Cardiopulmonary recirculation in patients with chronic heart failure and preserved left ventricular ejection fraction: the "Monday Morning Phenomenon"

Cardiopulmonary recirculation in patients with chronic heart failure and preserved left ventricular ejection fraction: the "Monday Morning Phenomenon" | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Cardiopulmonary recirculation in patients with chronic heart failure and preserved left ventricular ejection fraction: the "Monday Morning Phenomenon" Alexey Zulkarnaev, Ekaterina Parshina, Ilya Dmitriev, Vadim Stepanov, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5635403/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Sep, 2025 Read the published version in BMC Nephrology → Version 1 posted 15 You are reading this latest preprint version Abstract Background. Cardiopulmonary recirculation (CPR) is a known risk factor for heart failure (HF). Typically, the assessment is performed on the interdialytic day. Hemodialysis (HD) sessions can induce significant hemodynamic changes, which may be important for patients with HF and preserved ejection fraction (EF), in whom the risk may be underestimated. Objective. To evaluate the dynamics of CPR due to a HD session following a long interdialytic gap in patients with HF and preserved EF. Methods. The prospective cohort single-arm study included 20 adult HD patients who met the inclusion criteria: EF ≥ 50%, NYHA I-II, AVF volume blood flow (Qa) ≥ 1 L/min, CPR < 30%, interdialytic weight gain 1.2. All patients underwent transthoracic echocardiography on the third day after the previous HD session (Monday/Tuesday), 1 hour prior to and 2 hours after the session. In addition, the Qa of the brachial artery was measured. ClinicalTrials Id: NCT06394986 (May 01, 2024). Results. A reduction in cardiac preload after HD was evidenced by a decrease in the volume of cardiac chambers, as well as a reduction in pulmonary artery systolic pressure and arterial blood pressure. The EF and Qa slightly decreased (2.46% [95% CI 1.47; 3.45], p < 0.001 and 0.12 l/min [95% CI 0.09; 0.14], p < 0.001, respectively), whereas cardiac output decreased significantly (1.71 L/min [95% CI 0.8; 2.6], p < 0.001). This led to an increase in CPR of 5.1% [95% CI 3.9; 6.4], p < 0.001. As a result, in 5 patients, the CPR exceeded 30% after HD. In the sensitivity analysis, no parameters significantly associated with the variance CPR were identified. Conclusions. Some patients experience a significant increase in CPR after HD. However, the prognostic value of this phenomenon remains unclear. For patients with HF and normal or subnormal CPR measured on the interdialytic day, it is advisable to determine the CPR shortly after HD. This may serve as a 'stress test' to identify hidden hemodynamic disorders and manifest the cardiotoxic effect of AVF. arteriovenous fistula hemodialysis cardiac output heart failure volume blood flow cardiopulmonary recirculation Figures Figure 1 Figure 2 Figure 3 Introduction Cardiopulmonary recirculation (CPR), i.e., the ratio of cardiac output (CO) to arteriovenous fistula (AVF) flow volume (Qa), is a well-known risk factor for adverse cardiovascular events in patients undergoing hemodialysis (HD) [1]. No clear threshold is currently established for CPR value to definitively indicate AVF cardiotoxicity. In the literature, the CPR for AVF cardiotoxicity is commonly defined as > 20% [2] or > 30% [3]. In clinical settings, it is often a conditional definition of low, moderate or high risk of AVF cardiotoxicity based on interval estimates of CFR of 30%, respectively. The CPR is directly dependent on two parameters, which are determined by the patients hemodynamics. HD sessions are associated with significant changes in the volume of the circulating blood, redistribution of fluid between compartments, and alterations in the electrolyte composition of the blood. All of these factors could result in hemodynamic changes. It is therefore expected that CPR will vary significantly during dialysis sessions. The decision to reduce Qa may be quite obvious in patients with severe symptoms of heart failure (HF), particularly those with a reduced ejection fraction (EF) and a CPR close to or above 30%. However, in patients with moderate symptoms or subclinical HF with preserved ejection fraction (EF), the risk of specific complications may be underestimated owing to the variability of CPR. Research question: Will a HD session for a patient with chronic HF of NYHA class I-II with preserved left ventricular EF who receives chronic HD be accompanied by an increase in CPR? Study objective To evaluate the dynamics of CPR due to a HD session following a long interdialytic period in patients with chronic heart failure of NYHA class I-II with preserved ejection fraction. Materials and methods Study design. This prospective cohort single-arm study included 20 adult patients receiving HD treatment (June 2018–February 2019). ClinicalTrials Id: NCT06394986 (May 01, 2024). The inclusion criteria were signed informed consent, age over 18 years, HD treatment using native AVF, HF with preserved EF (≥ 50%), NYHA class I-II, Qa ≥ 1 L/min, CPR < 30%, interdialytic weight gain 1.2). The exclusion criteria were arrhythmias (except for first-degree AV block), HF NYHA class III-IV, valvular disease (except for mitral regurgitation I-II), and intradialytic hypo-/hypertension. The standard dialysis solution consisted of 2 mmol/L potassium, 5.5 mmol/L glucose, 1.5 mmol/L calcium, and 0.5 mmol/L magnesium. Sodium and ultrafiltration (UF) profiling was not applied. The examinations were conducted on Mondays (HD schedule: Monday-Wednesday-Friday) or on Tuesdays (HD schedule: Tuesday-Thursday-Saturday). Patients received HD during the second shift. All patients underwent 2D transthoracic echocardiography (TTE) one hour prior to and two hours after the HD session. Cardiac output was measured as the end-diastolic/systolic volume. Qa was measured on the brachial artery at the mid-arm using Doppler ultrasound. All ultrasound assessments before and after HD were performed by the same specialist. The diagnosis of HF was confirmed by a cardiologist and categorized according to the NYHA classification. Sample size calculation. Five patients meeting the inclusion/exclusion criteria were examined to assess CPR. Prior to HD, the mean (SD) CPR was 20.6% (2.7%), ranging from 17–24%. The desired effect size was defined as a change in the mean CPR from 21% to ± 5%. The number of patients required to reject the null hypothesis in a two-sided test with a significance level α of 0.01 and a power of 90% was calculated to be 18.6. Therefore, 20 patients were included in the study. Statistical analysis. The fit of the distribution of quantitative variables to the Gaussian distribution was assessed by visual analysis of frequency plots and quantile (Q-Q) plots. As no significant deviations were found, they were described as the means and standard deviations (SDs) with minimum and maximum values. The difference between time points was described as the raw mean difference with a 95% confidence interval. The significance of changes in quantitative variables was analysed via paired t tests. When analysing the joint distribution of qualitative variables, Stuart-Maxwell marginal homogeneity test was used. Univariable analysis of variance was used to analyse the relationship between quantitative and qualitative variables with more than two levels. A mixed effects linear model with patient ID as a random effect was used to test the hypothesis of significance of differences in the dynamics of two quantitative variables. The statistical analysis was performed in R 4.4. A two-sided level of significance was used. A P value of < 0.05 was considered statistically significant. Results The baseline characteristics of the patients are presented in Table 1 . We observed significant changes in several echocardiography parameters, indicating a decrease in cardiac preload, including a decrease in ventricular volume and stroke volume (and their corresponding indices), as well as a decrease in systolic pressure in the pulmonary artery. Despite the slightly decreased EF, we observed a pronounced decrease in CO with relatively stable AVF blood flow (Qa). This led to a significant increase in CPR (from 0.9 to 10.7%), as shown in Table 2 . As a result, 5 out of 20 patients after dialysis had a CPR above 30%, placing them in the high-risk group for cardiovascular complications and death. As shown in Fig. 1 , in 4 out of the 5 patients with a post-HD CPR of more than 30%, the initial CPR was less than 25%; in 2 patients, the initial CPR was less than 22%. Cardiac output decreased significantly more than Qa, as evidenced by the statistical significance of the coefficient for the interaction between 'time' and 'parameter' factors in a model of the following form: lmer(value ~ time*parameter + (1|patients)) – Fig. 2 . Since it was not initially planned in the study, we intentionally did not extensively analyse the factors contributing to the significant increase in CPR. This issue warrants further investigation. We provide this exploratory analysis in the appendix as a basis for future research. The degree of increase in CPR following dialysis was not associated with sex, the NYHA class of HF, or the type of therapy (Table 3 ). Nonetheless, the lower limits of the 95% CI for certain Pearson correlation coefficients (such as serum sodium, sodium gradient, systolic, diastolic, and mean arterial pressure) are close to zero. These findings suggest that future studies should establish the relationships between several factors and the extent to which the CPR increases after dialysis (Fig. 3 ). The power of this study is likely insufficient for this purpose. Discussion It is well known that hemodynamic changes manifest in the form of dose-dependent (mainly on UF) dynamics of echocardiography parameters. These are a decrease in the volume of cardiac chambers [4, 5], progression of diastolic dysfunction of the right and left ventricles [5], a decrease in the left ventricular myocardial mass [6] (however, the magnitude of the change appears to depend significantly on the assessment method [7]), development of regional left ventricle systolic dysfunction, which in turn is associated with poorer survival [8], and others. CO decreases after HD, even at acceptable UF rates and volumes [4, 9]. An intriguing experimental study conducted on pigs, whose average weight of 65 kg was comparable to that of humans, demonstrated convincingly that, in response to separate infusions of dobutamine and norepinephrine, CO significantly increased, whereas Qa remained virtually unchanged [10]. The fact that UF has practically no effect on Qa was also established by earlier studies [11–13]. One of the main parameters determining Qa is systemic arterial blood pressure [10, 11, 13]. For understandable reasons, we do not expect to observe a significant decrease in blood pressure in most patients without pronounced hypervolemia. In our study, systolic and mean blood pressure significantly decreased, but within relatively small ranges (Table 2 ). Hence, a similar Qa value can be anticipated after HD as before the session, which, considering the decreased CO, may result in an increase in CPR. Notably, studies have shown insignificant changes in CO after HD during both long and short interdialytic intervals, despite a decrease in body mass as a result of UF [5]. The results of our study confirm this indirectly: the lower limit of the 95% CI for the difference in mean CO before and after HD was 0.8 L/min (Table 2 ), and the minimum value for the CO difference was 690 mL/min. A study frequently cited in the context of CPR convincingly demonstrated that the severity of the decrease in CO is closely related to the UF rate [14]. The relationship between the UF and CO is clear. It is important to answer the question: during the conventional 4-4.5 hours of a dialysis session, what proportion of patients require an UF rate that results in a significant CO decrease? A recent scoping review revealed that a decrease in CO can be expected in a significant proportion of patients receiving intermittent haemodialysis, even those with relatively stable blood pressure [15]. Notably, the cited study included a mixed cohort of patients with chronic kidney disease and acute kidney injury, but we are still inclined to consider a decrease in CO during a dialysis session to be a more probable event than its absence. In our study, a significant proportion of patients transitioned from their existing risk category to a higher-risk category because of hemodynamic changes during the HD session. The KDOQI recommendations and cumulative evidence suggest that this may have prognostic implications. We intentionally evaluated the hemodynamic parameters of patients after a long interdialytic period. It is logical that patients in this scenario would exhibit more pronounced changes in echocardiography parameters (including CO dynamics) than patients after a short period [16–18]. In practice, two principles determine the timing of echocardiography. From a physiological perspective, the optimal day would be the interdialytic day, when the fluid compartments reach a more or less stable equilibrium. However, the day of echocardiography is often determined by the patient's convenience and is therefore the same day that they attend the clinic for regular HD session. Depending on the HD shift, the examination can be performed prior to or after the session. It is expected that the patient will demonstrate signs of volume overload and relatively low values of CPR prior to the HD session, while the opposite will be observed after the session, with an averaged assessment obtained on the interdialytic day. It is essential to determine the indications for echocardiography. For routine periodic examinations, the interdialytic day seems to be optimal. If the examination is intended to identify hidden hypervolemia, performing echocardiography immediately before the HD session can help in a comprehensive evaluation of the volume status. If a patient demonstrates gradual and unexplained progression of HF despite an optimal HD regimen (even with Qa values of less than 1.5–2 L/min) and modest interdialytic weight gain, the question arises whether to reduce Qa, or AVF closure, or convert to alternative modalities of renal replacement therapy or vascular access. In such cases, it is advisable to assess CPR after a regular HD session. After a session, HF symptom severity may decrease as a result of dehydration, a reduction in pulmonary hypertension and valvular regurgitation, etc., potentially leading to a false sense of well-being. Several publications indicate that the risk of death is significantly greater after a long interdialytic interval than after a short interval [19–23]. The increase in CPR after HD may have a detrimental synergistic effect on other risk factors. If patients with CPR > 30% are at a much greater risk of adverse events, the strength of this negative impact probably depends not only on the degree of CO reduction and maximum CPR achieved but also on the rate of CO recovery (with a relatively stable Qa), and the latter is currently undefined. UF (especially its rate) and the sodium gradient between the blood and dialysate appear to be the main potential causes of the decrease in CO. Further research should focus on investigating the nature of the correlation between these parameters and CO and its recovery rate following HD. This will help identify patients who are expected to have a significant increase in CPR. Furthermore, it is essential to establish thresholds for CPR that have demonstrated prognostic value, as well as to quantify the detrimental impact. These thresholds may vary between specific patient groups (e.g., patients with reduced EF, patients with pronounced HF, etc.). Study limitations We did not consider possible changes in cardiac conduction and rhythm before and after HD, although they are expected to develop. [23–26]. However, these changes are likely dose dependent on UF and electrolyte disturbances [27, 28]. Before we recruited the study sample, inclusion criteria were established that partially reduced the risk of bias from these factors. The 2D TTE we used may provide a biased absolute estimate of true stroke volume (or ejection fraction), but it yields an inner-observer agreement comparable to that of 3D echocardiography [29] and cardiac magnetic resonance imaging [30]. Conclusion Some patients experience a significant increase in CPR after HD. However, the prognostic value of this phenomenon remains uncertain. For patients with HF and normal or subnormal CPR measured on the interdialytic day, it is advisable to determine the CPR shortly after HD. This may serve as a 'stress test' to identify hidden hemodynamic disorders and manifest the cardiotoxic effect of AVF. Declarations The study was approved by the local independent ethics committee of the Moscow Regional Research and Clinical Institute ("MONIKI"), protocol No. 5 dated May 25, 2018. All participants were informed about the study and gave their written informed consent. All authors have read and approved the final version of the manuscript. Availability of data and material: The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request. Funding: This study was sponsored by the Moscow Center for Innovative Technologies in Healthcare. The authors declare no conflict of interests. Authors’ contribution. AZ – study concept and design, statistical analysis, and supervision, manuscript editing. EP – critical analysis and manuscript editing. ID – data collection and control, manuscript editing. VS – study coordination, data collection and control, manuscript editing. NF – study coordination, manuscript writing and editing. References Agarwal AK. Systemic Effects of Hemodialysis Access. Adv Chronic Kidney Dis. 2015;22:459–65. Basile C, Lomonte C, Vernaglione L, Casucci F, Antonelli M, Losurdo N. The relationship between the flow of arteriovenous fistula and cardiac output in haemodialysis patients. Nephrol Dial Transplant. 2008;23:282–7. Blanchard V, Courtellemont C, Cariou E, Fournier P, Lavie-Badie Y, Pascal P, et al. Cardiac impact of arteriovenous fistulas: what tools to assess? Heart Vessels. 2020;35:1583–93. Guler HS, Tulunay Kaya C, Kumru G, Kosku H, Ozyuncu N, Sengul S, et al. Acute stunning effect of hemodialysis on myocardial performance: A three-dimensional speckle tracking echocardiographic study. Artif Organs. 2020;44:1081–9. Sarafidis PA, Kamperidis V, Loutradis C, Tsilonis K, Mpoutsiouki F, Saratzis A, et al. Haemodialysis acutely deteriorates left and right diastolic function and myocardial performance: an effect related to high ultrafiltration volumes? Nephrol Dial Transplant. 2017;32:1402–9. Ganda A, Weiner SD, Chudasama NL, Valeri AM, Jadoon A, Shimbo D, et al. Echocardiographic changes following hemodialysis initiation in patients with advanced chronic kidney disease and symptomatic heart failure with reduced ejection fraction. Clin Nephrol. 2012;77:366–75. Kristensen CB, Steensgaard-Hansen F, Myhr KA, Løkkegaard NJ, Finsen SH, Hassager C, et al. Left Ventricular Mass Assessment by 1- and 2-Dimensional Echocardiographic Methods in Hemodialysis Patients: Changes in Left Ventricular Volume Using Echocardiography Before and After a Hemodialysis Session. Kidney Med. 2020;2:578-588.e1. Assa S, Hummel YM, Voors AA, Kuipers J, Westerhuis R, de Jong PE, et al. Hemodialysis-Induced Regional Left Ventricular Systolic Dysfunction: Prevalence, Patient and Dialysis Treatment-Related Factors, and Prognostic Significance. Clin J Am Soc Nephrol. 2012;7:1615–23. Morales-Alvarez R, Martínez-Memije R, Becerra-Luna B, García-Paz P, Infante O, Palma-Ramírez A, et al. Hemodynamic Response to Hemodialysis With Ultrafiltration Rate Profiles Either Gradually Decreasing or Gradually Increasing. Artif Organs. 2016;40:684–91. Valerianova A, Mlcek M, Malik J, Grus T, Tejkl L, Kolosova B, et al. Comparing the hemodynamic effect of a large arteriovenous fistula during high and low cardiac output states. Front Physiol. 2023;14:1180224. Park HS, Kang SH, Chung BH, Choi BS, Park CW, Yang CW, et al. Effect of intradialytic change in blood pressure and ultrafiltration volume on the variation in access flow measured by ultrasound dilution. Kidney Res Clin Pract. 2013;32:16–20. Ronco C, Brendolan A, Crepaldi C, D’Intini V, Sergeyeva O, Levin NW. Noninvasive transcutaneous access flow measurement before and after hemodialysis: impact of hematocrit and blood pressure. Blood Purif. 2002;20:376–9. Sands J, Glidden D, Miranda C. Access flow measured during hemodialysis. ASAIO J. 1996;42:M530-532. Pandeya S, Lindsay RM. The relationship between cardiac output and access flow during hemodialysis. ASAIO J. 1999;45:135–8. Spano S, Maeda A, Lam J, Chaba A, See E, Mount P, et al. Cardiac Output Changes during Renal Replacement Therapy: A Scoping Review. Blood Purif. 2023. https://doi.org/10.1159/000534601. Obokata M, Negishi K, Marwick TH, Kurosawa K, Ishida H, Ito K, et al. Comparison of different interdialytic intervals among hemodialysis patients on their echocardiogram-based cardiovascular parameters. Am Heart J. 2015;169:523-530.e2. Tsilonis K, Sarafidis PA, Kamperidis V, Loutradis C, Georgianos PI, Imprialos K, et al. Echocardiographic Parameters During Long and Short Interdialytic Intervals in Hemodialysis Patients. Am J Kidney Dis. 2016;68:772–81. Loutradis C, Sarafidis PA, Papadopoulos CE, Papagianni A, Zoccali C. The Ebb and Flow of Echocardiographic Cardiac Function Parameters in Relationship to Hemodialysis Treatment in Patients with ESRD. J Am Soc Nephrol. 2018;29:1372–81. Vareesangthip K, Yincharoen P, Winijkul A, Chanchairujira T. Cardiac arrhythmia during early-week and mid-week dialysis in hemodialysis patients. Ther Apher Dial. 2021;25:890–8. Uwumiro FE, Okpujie VO, Oyesomi A, Madu FC, Ilelaboye A, Shielu ML, et al. Weekend Effect on Mortality, Access to Renal Replacement Therapy, and Other Outcomes Among Patients With End-Stage Renal Disease: A Retrospective Analysis of the Nationwide Inpatient Sample. Cureus. 2023;15:e34139. Zhang H, Schaubel DE, Kalbfleisch JD, Bragg-Gresham JL, Robinson BM, Pisoni RL, et al. Dialysis outcomes and analysis of practice patterns suggests the dialysis schedule affects day-of-week mortality. Kidney Int. 2012;81:1108–15. Foley RN, Gilbertson DT, Murray T, Collins AJ. Long interdialytic interval and mortality among patients receiving hemodialysis. N Engl J Med. 2011;365:1099–107. Green D, Roberts PR, New DI, Kalra PA. Sudden cardiac death in hemodialysis patients: an in-depth review. Am J Kidney Dis. 2011;57:921–9. Franczyk B, Gluba-Brzózka A, Bartnicki P, Rysz J. The occurrence of atrial fibrillation in dialysis patients and its association with left atrium volume before and after dialysis. Int Urol Nephrol. 2017;49:1071–7. Flythe JE, Liu S, Montez-Rath ME, Winkelmayer WC, Chang TI. Ultrafiltration rate and incident atrial fibrillation among older individuals initiating hemodialysis. Nephrol Dial Transplant. 2021;36:2084–93. Bignotto LH, Kallás ME, Djouki RJT, Sassaki MM, Voss GO, Soto CL, et al. Electrocardiographic findings in chronic hemodialysis patients. J Bras Nefrol. 2012;34:235–42. Joki N, Tokumoto M, Takahashi N, Nishimura M. Current Perspectives on Sudden Cardiac Death in Hemodialysis Patients. Contrib Nephrol. 2018;196:5–12. Ozportakal H, Ozkok A, Alkan O, Bulut AS, Boyraz M, Inanir M, et al. Hemodialysis-induced repolarization abnormalities on ECG are influenced by serum calcium levels and ultrafiltration volumes. Int Urol Nephrol. 2017;49:509–15. Lyng Lindgren F, Tayal B, Bundgaard Ringgren K, Ascanius Jacobsen P, Hay Kragholm K, Zaremba T, et al. The variability of 2D and 3D transthoracic echocardiography applied in a general population : Intermodality, inter- and intraobserver variability. Int J Cardiovasc Imaging. 2022;38:2177–90. Esenboğa K, Kılıçkap M, Peker E, Kozluca V, Koca Ç, Kaya CT, et al. Agreement between visually estimated left ventricular ejection fraction on echocardiography and quantitative measurements using cardiac magnetic resonance. Anatol J Cardiol. 2022;26:127–32. Tables Table 1: Baseline patient characteristics. Mean, standard deviation and range or absolute and relative frequency are given. N=20 Male 8 (40%) Age, years 53.7 (7.7), 41.0 to 67.0 Hemodialysis vintage, months 49.0 (11.1), 33.0 to 72.0 Body mass index, kg/m 2 28.2 (3.8), 22.9 to 36.0 Residual diuresis, ml / day 605 (256), 200 to 900 Interdialytic weight gain absolute, kg 3.2 (0.8), 1.9 to 4.7 relative to dry weight, % 4.1 (0.8), 2.9 to 5.0 Effective dialysis time, minutes 256.3 (5.3), 248.0 to 265.0 Ultrafiltration rate, mL/min/kg 0.159 (0.033), 0.110 to 0.195 Hemodialysis modality high-flux dialysis 15 (75%) hemodiafiltration 5 (25%) Serum albumin, g/l 42.8 (3.2), 38.0 to 48.0 Serum sodium, mmol/l 139.6 (1.2), 138.0 to 141.0 Dialysate / predialysis serum sodium gradient, mmol/l 0.1 (3.0), -4.0 to 4.0 Charlson comorbidity index, points 5.1 (1.6), 3.0 to 8.0 AVF (native) Forearm, lower third 12 (60%) 8 (40%) NYHA class I 9 (45%) class II 11 (55%) Antihypertensive therapy none 3 (15%) beta-blockers 7 (35%) beta-blockers + angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers 10 (50%) Table 2: Dynamics of echocardiographic parameters Before HD After HD Raw mean difference 95% CI P value Qa, l/min 1.4 (0,31), 1-2.1 1.3 (0.29). 0.95- 1.95 ↓ 0.12 0.09; 0.14 <0.001 Cardiac output, l/min 6.7 (1.5), 4.3-9.4 5 (1.3), 3.2-7.8 ↓ 1.71 1.41; 2.0 <0.001 Cardiac index, l/min/m 2 3.5 (0.67), 2.27-4.9 2.6 (0.59), 1.6-4 ↓ 0.89 0.74; 1.03 <0.001 CPR, % 21.3 (2.2), 17.5-27.3 26.4 (3.6), 20.8-31.7 ↑ 5.1 3.9; 6.4 <0.001 CPR <20% 7 0 0.002 20%-29.9% 13 15 NA NA ≥30 0 5 EDV, ml 147 (26.0), 106-182 112.5 (19.6), 76-141 ↓ 34.5 30.6; 38.3 <0.001 EDV index, ml/m 2 76.6 (10.6), 58.8-96.5 58.6 (8.1), 42.1-73.2 ↓17.9 16.2, 19.7 <0.001 ESV, ml 56.9 (12.4), 31-79 46.4 (10.0), 27-68 ↓ 10.5 8.9; 12.1 <0.001 ESV index, ml/m 2 29.7 (6), 17.8-41 24.2 (4.8), 15.5-34.4 ↓5.49 4.67, 6.32 <0.001 Ejection fraction, % 61.1 (6.6), 51.1-72.9 58.7 (6.4), 48.6-69.9 ↓ 2.46 1.47; 3.45 <0.001 Heart rate, beats per min 74.6 (7.6), 62-88 75.5 (7.9), 61-90 ↑ 0.85 -1.22; 2.92 0.4 Stroke volume, ml 90.1 (20.4), 65-132 66.2 (14.7), 42-95 ↓ 24 20.4; 27.5 <0.001 Stroke volume index, ml/m 2 46.9 (8.6), 34.3-62.6 34.5 (6.3), 23.3-48.7 ↓12.4 10.9, 14.0 <0.001 Systolic BP, mmHg 133 (15.1), 110-160 123.5 (10.5), 110-140 ↓9.5 3.48, 15.5 0.004 Diastolic BP, mmHg 82.5 (10.2), 60-100 77.5 (7.5), 60-90 ↓5 -0.37; 10.4 0.066 Mean BP, mmHg 107.8 (12.0), 87.5-130 100.5 (8.3), 85-115 ↓ 7.25 2.02; 12.5 0.0 09 ePASP, mmHg 36.6 (9.1), 25-55 29 (5.4), 22-42 ↓ 7.6 5.28; 9.92 <0.001 HD – Hemodialysis, Qa – AVF volume blood flow, CPR – cardiopulmonary recirculation, EDV – end-diastolic volume, ESV – end-systolic volume, BP – blood pressure, ePASP – estimated pulmonary artery systolic pressure Table 3: Association of nominal characteristics with the delta of the CPR. Mean, SD and range are given. T-test and analysis of variance were used to assess the significance of the association between cardio-fistula recirculation delta and categorical variables. Cardiopulmonary recirculation delta P value Sex Male 5.2 (3.2), 0.9-10.1 0.878 Female 5.0 (2.4), 1.5-10.7 NYHA I 4.8 (2.3), 1.5- 9.0 0.642 II 5.4 (3.0), 0.9-10.7 Therapy None 2.6 (1.1), 1.5-3.6 0.122 Beta-blockers 4.8 (2.7), 0.9-9.0 Beta-blockers + Angiotensin-converting enzyme inhibitors / Angiotensin II receptor blockers 6.1 (2.6), 2.6-10.7 Appendix Appendix is not available with this version Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 01 Sep, 2025 Read the published version in BMC Nephrology → Version 1 posted Editorial decision: Revision requested 07 Jul, 2025 Reviews received at journal 07 Jul, 2025 Reviews received at journal 06 Jul, 2025 Reviews received at journal 27 Jun, 2025 Reviewers agreed at journal 26 Jun, 2025 Reviewers agreed at journal 25 Jun, 2025 Reviewers agreed at journal 23 Jun, 2025 Reviewers agreed at journal 22 Jun, 2025 Reviews received at journal 13 Feb, 2025 Reviewers agreed at journal 05 Feb, 2025 Reviewers invited by journal 24 Jan, 2025 Editor invited by journal 19 Dec, 2024 Editor assigned by journal 18 Dec, 2024 Submission checks completed at journal 18 Dec, 2024 First submitted to journal 12 Dec, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5635403","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":392247521,"identity":"defb24e6-454c-4af9-a619-d8f160cfc2bb","order_by":0,"name":"Alexey Zulkarnaev","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA00lEQVRIiWNgGAWjYBAC+8P8Dx98qLCRA3EOPCBKz/EeZsMZZ9KMwVoSiNJy5gybNG/b4cQGEIcoLYwzco9Jzmw7nD4/7PBDoC12croNBLQwS+QlW3w4l5678XaaAVBLsrHZAQJa2CQSDG/OKLPO3Tg7AaTlQOI2Qlp4JBIMpHnYmNMNZ6d/IE6LBM8ZI2meNucEeekcIm0xYG9LBgWy4QbpnIIDCQZE+MWAmfkgKCrl5Wenb/7wocJOjqAWhF6wSgNilYOAfAMpqkfBKBgFo2BEAQCkcko4CCnl9gAAAABJRU5ErkJggg==","orcid":"","institution":"Moscow Regional Research and Clinical Institute (\"MONIKI\")","correspondingAuthor":true,"prefix":"","firstName":"Alexey","middleName":"","lastName":"Zulkarnaev","suffix":""},{"id":392247523,"identity":"00428120-a1c8-46ed-b82c-db4b58679145","order_by":1,"name":"Ekaterina Parshina","email":"","orcid":"","institution":"Saint Petersburg State University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Ekaterina","middleName":"","lastName":"Parshina","suffix":""},{"id":392247528,"identity":"333b20d4-7aa2-496f-9b2f-362697f50e59","order_by":2,"name":"Ilya Dmitriev","email":"","orcid":"","institution":"Pirogov Russian National Research Medical University","correspondingAuthor":false,"prefix":"","firstName":"Ilya","middleName":"","lastName":"Dmitriev","suffix":""},{"id":392247529,"identity":"dcdfecd2-0de9-483a-94f1-84d235561915","order_by":3,"name":"Vadim Stepanov","email":"","orcid":"","institution":"Moscow Regional Research and Clinical Institute (\"MONIKI\")","correspondingAuthor":false,"prefix":"","firstName":"Vadim","middleName":"","lastName":"Stepanov","suffix":""},{"id":392247532,"identity":"56bd10fb-adcc-4aee-b675-3e086c2d72ba","order_by":4,"name":"Natalia Fominykh","email":"","orcid":"","institution":"Moscow Regional Research and Clinical Institute (\"MONIKI\")","correspondingAuthor":false,"prefix":"","firstName":"Natalia","middleName":"","lastName":"Fominykh","suffix":""}],"badges":[],"createdAt":"2024-12-13 04:38:18","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5635403/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5635403/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12882-025-04431-6","type":"published","date":"2025-09-01T15:57:10+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":72334092,"identity":"8d7479e8-1342-479e-8598-5605158d2bdf","added_by":"auto","created_at":"2024-12-25 15:30:37","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1798997,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in cardiopulmonary recirculation as a result of a HD session. Mean, SD and individual values are given. HD – Hemodialysis\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-5635403/v1/42c855bf8f7f319abd802640.png"},{"id":72334710,"identity":"e6e00205-36e7-4ad9-a488-3f6df41ab0a7","added_by":"auto","created_at":"2024-12-25 15:38:37","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":352366,"visible":true,"origin":"","legend":"\u003cp\u003eChanges in cardiac output and AVF volume blood flow (Qa) as a result of a HD session. Mean, SD and significance of the coefficient for the interaction between 'time' and 'parameter' factors are given. HD – Hemodialysis\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-5635403/v1/e2112ccc3f165edb41cd5bec.png"},{"id":72334091,"identity":"57ae95f2-3f6d-408d-b706-ca4e730b895b","added_by":"auto","created_at":"2024-12-25 15:30:37","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":1621828,"visible":true,"origin":"","legend":"\u003cp\u003ePairwise correlations of the difference in CPR before and after HD (delta) with various parameters. Pearson correlation coefficient, [95% CI] are given.\u003c/p\u003e\n\u003cp\u003eHD – Hemodialysis, BMI - body mass index, BSA - body surface area, CCI – Charlson comorbidity index, Qa – AVF volume blood flow, CPR – cardiopulmonary recirculation, EDV – end-diastolic volume, ESV – end-systolic volume, ePASP – (estimated) systolic pulmonary artery pressure, BP –blood pressure\u003c/p\u003e","description":"","filename":"Fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-5635403/v1/b1303ad4e1aef6c63aab1cbb.png"},{"id":90827921,"identity":"583f8c47-6e86-45bd-85e5-a10d6c7f49ae","added_by":"auto","created_at":"2025-09-08 16:03:14","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4300433,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5635403/v1/76236060-001f-46da-a063-60fcf680bd38.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Cardiopulmonary recirculation in patients with chronic heart failure and preserved left ventricular ejection fraction: the \"Monday Morning Phenomenon\"","fulltext":[{"header":"Introduction","content":"\u003cp\u003eCardiopulmonary recirculation (CPR), i.e., the ratio of cardiac output (CO) to arteriovenous fistula (AVF) flow volume (Qa), is a well-known risk factor for adverse cardiovascular events in patients undergoing hemodialysis (HD) [1]. No clear threshold is currently established for CPR value to definitively indicate AVF cardiotoxicity. In the literature, the CPR for AVF cardiotoxicity is commonly defined as \u0026gt; 20% [2] or \u0026gt; 30% [3]. In clinical settings, it is often a conditional definition of low, moderate or high risk of AVF cardiotoxicity based on interval estimates of CFR of \u0026lt; 20%, 20–30% or \u0026gt; 30%, respectively.\u003c/p\u003e\u003cp\u003eThe CPR is directly dependent on two parameters, which are determined by the patients hemodynamics. HD sessions are associated with significant changes in the volume of the circulating blood, redistribution of fluid between compartments, and alterations in the electrolyte composition of the blood. All of these factors could result in hemodynamic changes. It is therefore expected that CPR will vary significantly during dialysis sessions.\u003c/p\u003e\u003cp\u003eThe decision to reduce Qa may be quite obvious in patients with severe symptoms of heart failure (HF), particularly those with a reduced ejection fraction (EF) and a CPR close to or above 30%. However, in patients with moderate symptoms or subclinical HF with preserved ejection fraction (EF), the risk of specific complications may be underestimated owing to the variability of CPR.\u003c/p\u003e\u003cp\u003eResearch question: Will a HD session for a patient with chronic HF of NYHA class I-II with preserved left ventricular EF who receives chronic HD be accompanied by an increase in CPR?\u003c/p\u003e\n\u003ch3\u003eStudy objective\u003c/h3\u003e\n\u003cp\u003eTo evaluate the dynamics of CPR due to a HD session following a long interdialytic period in patients with chronic heart failure of NYHA class I-II with preserved ejection fraction.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003e \u003cem\u003eStudy design.\u003c/em\u003e This prospective cohort single-arm study included 20 adult patients receiving HD treatment (June 2018–February 2019). ClinicalTrials Id: NCT06394986 (May 01, 2024).\u003c/p\u003e\u003cp\u003eThe inclusion criteria were signed informed consent, age over 18 years, HD treatment using native AVF, HF with preserved EF (≥ 50%), NYHA class I-II, Qa ≥ 1 L/min, CPR \u0026lt; 30%, interdialytic weight gain \u0026lt; 5% of dry weight, and an adequate HD dose (eKt/V \u0026gt; 1.2). The exclusion criteria were arrhythmias (except for first-degree AV block), HF NYHA class III-IV, valvular disease (except for mitral regurgitation I-II), and intradialytic hypo-/hypertension. The standard dialysis solution consisted of 2 mmol/L potassium, 5.5 mmol/L glucose, 1.5 mmol/L calcium, and 0.5 mmol/L magnesium. Sodium and ultrafiltration (UF) profiling was not applied.\u003c/p\u003e\u003cp\u003eThe examinations were conducted on Mondays (HD schedule: Monday-Wednesday-Friday) or on Tuesdays (HD schedule: Tuesday-Thursday-Saturday). Patients received HD during the second shift. All patients underwent 2D transthoracic echocardiography (TTE) one hour prior to and two hours after the HD session. Cardiac output was measured as the end-diastolic/systolic volume. Qa was measured on the brachial artery at the mid-arm using Doppler ultrasound. All ultrasound assessments before and after HD were performed by the same specialist.\u003c/p\u003e\u003cp\u003eThe diagnosis of HF was confirmed by a cardiologist and categorized according to the NYHA classification.\u003c/p\u003e\u003cp\u003e\u003cem\u003eSample size calculation.\u003c/em\u003e Five patients meeting the inclusion/exclusion criteria were examined to assess CPR. Prior to HD, the mean (SD) CPR was 20.6% (2.7%), ranging from 17–24%. The desired effect size was defined as a change in the mean CPR from 21% to ± 5%. The number of patients required to reject the null hypothesis in a two-sided test with a significance level α of 0.01 and a power of 90% was calculated to be 18.6. Therefore, 20 patients were included in the study.\u003c/p\u003e\u003cp\u003e\u003cem\u003eStatistical analysis.\u003c/em\u003e The fit of the distribution of quantitative variables to the Gaussian distribution was assessed by visual analysis of frequency plots and quantile (Q-Q) plots. As no significant deviations were found, they were described as the means and standard deviations (SDs) with minimum and maximum values. The difference between time points was described as the raw mean difference with a 95% confidence interval. The significance of changes in quantitative variables was analysed via paired t tests. When analysing the joint distribution of qualitative variables, Stuart-Maxwell marginal homogeneity test was used. Univariable analysis of variance was used to analyse the relationship between quantitative and qualitative variables with more than two levels. A mixed effects linear model with patient ID as a random effect was used to test the hypothesis of significance of differences in the dynamics of two quantitative variables.\u003c/p\u003e\u003cp\u003eThe statistical analysis was performed in R 4.4. A two-sided level of significance was used. A P value of \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e The baseline characteristics of the patients are presented in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eWe observed significant changes in several echocardiography parameters, indicating a decrease in cardiac preload, including a decrease in ventricular volume and stroke volume (and their corresponding indices), as well as a decrease in systolic pressure in the pulmonary artery. Despite the slightly decreased EF, we observed a pronounced decrease in CO with relatively stable AVF blood flow (Qa). This led to a significant increase in CPR (from 0.9 to 10.7%), as shown in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eAs a result, 5 out of 20 patients after dialysis had a CPR above 30%, placing them in the high-risk group for cardiovascular complications and death. As shown in Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e, in 4 out of the 5 patients with a post-HD CPR of more than 30%, the initial CPR was less than 25%; in 2 patients, the initial CPR was less than 22%.\u003c/p\u003e\u003cp\u003eCardiac output decreased significantly more than Qa, as evidenced by the statistical significance of the coefficient for the interaction between 'time' and 'parameter' factors in a model of the following form: lmer(value ~ time*parameter + (1|patients)) – Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003eSince it was not initially planned in the study, we intentionally did not extensively analyse the factors contributing to the significant increase in CPR. This issue warrants further investigation. We provide this exploratory analysis in the appendix as a basis for future research. The degree of increase in CPR following dialysis was not associated with sex, the NYHA class of HF, or the type of therapy (Table \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eNonetheless, the lower limits of the 95% CI for certain Pearson correlation coefficients (such as serum sodium, sodium gradient, systolic, diastolic, and mean arterial pressure) are close to zero. These findings suggest that future studies should establish the relationships between several factors and the extent to which the CPR increases after dialysis (Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e). The power of this study is likely insufficient for this purpose.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003e It is well known that hemodynamic changes manifest in the form of dose-dependent (mainly on UF) dynamics of echocardiography parameters. These are a decrease in the volume of cardiac chambers [4, 5], progression of diastolic dysfunction of the right and left ventricles [5], a decrease in the left ventricular myocardial mass [6] (however, the magnitude of the change appears to depend significantly on the assessment method [7]), development of regional left ventricle systolic dysfunction, which in turn is associated with poorer survival [8], and others.\u003c/p\u003e\u003cp\u003eCO decreases after HD, even at acceptable UF rates and volumes [4, 9]. An intriguing experimental study conducted on pigs, whose average weight of 65 kg was comparable to that of humans, demonstrated convincingly that, in response to separate infusions of dobutamine and norepinephrine, CO significantly increased, whereas Qa remained virtually unchanged [10].\u003c/p\u003e\u003cp\u003eThe fact that UF has practically no effect on Qa was also established by earlier studies [11–13]. One of the main parameters determining Qa is systemic arterial blood pressure [10, 11, 13]. For understandable reasons, we do not expect to observe a significant decrease in blood pressure in most patients without pronounced hypervolemia. In our study, systolic and mean blood pressure significantly decreased, but within relatively small ranges (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e). Hence, a similar Qa value can be anticipated after HD as before the session, which, considering the decreased CO, may result in an increase in CPR.\u003c/p\u003e\u003cp\u003eNotably, studies have shown insignificant changes in CO after HD during both long and short interdialytic intervals, despite a decrease in body mass as a result of UF [5]. The results of our study confirm this indirectly: the lower limit of the 95% CI for the difference in mean CO before and after HD was 0.8 L/min (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e), and the minimum value for the CO difference was 690 mL/min.\u003c/p\u003e\u003cp\u003eA study frequently cited in the context of CPR convincingly demonstrated that the severity of the decrease in CO is closely related to the UF rate [14]. The relationship between the UF and CO is clear. It is important to answer the question: during the conventional 4-4.5 hours of a dialysis session, what proportion of patients require an UF rate that results in a significant CO decrease? A recent scoping review revealed that a decrease in CO can be expected in a significant proportion of patients receiving intermittent haemodialysis, even those with relatively stable blood pressure [15]. Notably, the cited study included a mixed cohort of patients with chronic kidney disease and acute kidney injury, but we are still inclined to consider a decrease in CO during a dialysis session to be a more probable event than its absence.\u003c/p\u003e\u003cp\u003eIn our study, a significant proportion of patients transitioned from their existing risk category to a higher-risk category because of hemodynamic changes during the HD session. The KDOQI recommendations and cumulative evidence suggest that this may have prognostic implications. We intentionally evaluated the hemodynamic parameters of patients after a long interdialytic period. It is logical that patients in this scenario would exhibit more pronounced changes in echocardiography parameters (including CO dynamics) than patients after a short period [16–18].\u003c/p\u003e\u003cp\u003eIn practice, two principles determine the timing of echocardiography. From a physiological perspective, the optimal day would be the interdialytic day, when the fluid compartments reach a more or less stable equilibrium. However, the day of echocardiography is often determined by the patient's convenience and is therefore the same day that they attend the clinic for regular HD session. Depending on the HD shift, the examination can be performed prior to or after the session. It is expected that the patient will demonstrate signs of volume overload and relatively low values of CPR prior to the HD session, while the opposite will be observed after the session, with an averaged assessment obtained on the interdialytic day. It is essential to determine the indications for echocardiography. For routine periodic examinations, the interdialytic day seems to be optimal. If the examination is intended to identify hidden hypervolemia, performing echocardiography immediately before the HD session can help in a comprehensive evaluation of the volume status.\u003c/p\u003e\u003cp\u003eIf a patient demonstrates gradual and unexplained progression of HF despite an optimal HD regimen (even with Qa values of less than 1.5–2 L/min) and modest interdialytic weight gain, the question arises whether to reduce Qa, or AVF closure, or convert to alternative modalities of renal replacement therapy or vascular access. In such cases, it is advisable to assess CPR after a regular HD session. After a session, HF symptom severity may decrease as a result of dehydration, a reduction in pulmonary hypertension and valvular regurgitation, etc., potentially leading to a false sense of well-being.\u003c/p\u003e\u003cp\u003eSeveral publications indicate that the risk of death is significantly greater after a long interdialytic interval than after a short interval [19–23]. The increase in CPR after HD may have a detrimental synergistic effect on other risk factors. If patients with CPR \u0026gt; 30% are at a much greater risk of adverse events, the strength of this negative impact probably depends not only on the degree of CO reduction and maximum CPR achieved but also on the rate of CO recovery (with a relatively stable Qa), and the latter is currently undefined.\u003c/p\u003e\u003cp\u003eUF (especially its rate) and the sodium gradient between the blood and dialysate appear to be the main potential causes of the decrease in CO. Further research should focus on investigating the nature of the correlation between these parameters and CO and its recovery rate following HD. This will help identify patients who are expected to have a significant increase in CPR. Furthermore, it is essential to establish thresholds for CPR that have demonstrated prognostic value, as well as to quantify the detrimental impact. These thresholds may vary between specific patient groups (e.g., patients with reduced EF, patients with pronounced HF, etc.).\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eStudy limitations\u003c/strong\u003e\u003c/p\u003e\u003cp\u003e We did not consider possible changes in cardiac conduction and rhythm before and after HD, although they are expected to develop. [23–26]. However, these changes are likely dose dependent on UF and electrolyte disturbances [27, 28]. Before we recruited the study sample, inclusion criteria were established that partially reduced the risk of bias from these factors.\u003c/p\u003e\u003cp\u003eThe 2D TTE we used may provide a biased absolute estimate of true stroke volume (or ejection fraction), but it yields an inner-observer agreement comparable to that of 3D echocardiography [29] and cardiac magnetic resonance imaging [30].\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003e Some patients experience a significant increase in CPR after HD. However, the prognostic value of this phenomenon remains uncertain. For patients with HF and normal or subnormal CPR measured on the interdialytic day, it is advisable to determine the CPR shortly after HD. This may serve as a 'stress test' to identify hidden hemodynamic disorders and manifest the cardiotoxic effect of AVF.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eThe study was approved by the local independent ethics committee of the Moscow Regional Research and Clinical Institute (\u0026quot;MONIKI\u0026quot;), protocol No. 5 dated May 25, 2018. All participants were informed about the study and gave their written informed consent.\u003c/p\u003e\n\u003cp\u003eAll authors have read and approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003eAvailability of data and material: The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003eFunding: This study was sponsored by the Moscow Center for Innovative Technologies in Healthcare.\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interests.\u003c/p\u003e\n\u003cp\u003eAuthors\u0026rsquo; contribution. AZ \u0026ndash; study concept and design, statistical analysis, and supervision, manuscript editing. EP \u0026ndash; critical analysis and manuscript editing. ID \u0026ndash; data collection and control, manuscript editing. VS \u0026ndash; study coordination, data collection and control, manuscript editing. NF \u0026ndash; study coordination, manuscript writing and editing.\u0026nbsp;\u003c/p\u003e\n"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAgarwal AK. Systemic Effects of Hemodialysis Access. Adv Chronic Kidney Dis. 2015;22:459\u0026ndash;65.\u003c/li\u003e\n\u003cli\u003eBasile C, Lomonte C, Vernaglione L, Casucci F, Antonelli M, Losurdo N. The relationship between the flow of arteriovenous fistula and cardiac output in haemodialysis patients. Nephrol Dial Transplant. 2008;23:282\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003eBlanchard V, Courtellemont C, Cariou E, Fournier P, Lavie-Badie Y, Pascal P, et al. Cardiac impact of arteriovenous fistulas: what tools to assess? Heart Vessels. 2020;35:1583\u0026ndash;93.\u003c/li\u003e\n\u003cli\u003eGuler HS, Tulunay Kaya C, Kumru G, Kosku H, Ozyuncu N, Sengul S, et al. Acute stunning effect of hemodialysis on myocardial performance: A three-dimensional speckle tracking echocardiographic study. Artif Organs. 2020;44:1081\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eSarafidis PA, Kamperidis V, Loutradis C, Tsilonis K, Mpoutsiouki F, Saratzis A, et al. Haemodialysis acutely deteriorates left and right diastolic function and myocardial performance: an effect related to high ultrafiltration volumes? Nephrol Dial Transplant. 2017;32:1402\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eGanda A, Weiner SD, Chudasama NL, Valeri AM, Jadoon A, Shimbo D, et al. Echocardiographic changes following hemodialysis initiation in patients with advanced chronic kidney disease and symptomatic heart failure with reduced ejection fraction. Clin Nephrol. 2012;77:366\u0026ndash;75.\u003c/li\u003e\n\u003cli\u003eKristensen CB, Steensgaard-Hansen F, Myhr KA, L\u0026oslash;kkegaard NJ, Finsen SH, Hassager C, et al. Left Ventricular Mass Assessment by 1- and 2-Dimensional Echocardiographic Methods in Hemodialysis Patients: Changes in Left Ventricular Volume Using Echocardiography Before and After a Hemodialysis Session. Kidney Med. 2020;2:578-588.e1.\u003c/li\u003e\n\u003cli\u003eAssa S, Hummel YM, Voors AA, Kuipers J, Westerhuis R, de Jong PE, et al. Hemodialysis-Induced Regional Left Ventricular Systolic Dysfunction: Prevalence, Patient and Dialysis Treatment-Related Factors, and Prognostic Significance. Clin J Am Soc Nephrol. 2012;7:1615\u0026ndash;23.\u003c/li\u003e\n\u003cli\u003eMorales-Alvarez R, Mart\u0026iacute;nez-Memije R, Becerra-Luna B, Garc\u0026iacute;a-Paz P, Infante O, Palma-Ram\u0026iacute;rez A, et al. Hemodynamic Response to Hemodialysis With Ultrafiltration Rate Profiles Either Gradually Decreasing or Gradually Increasing. Artif Organs. 2016;40:684\u0026ndash;91.\u003c/li\u003e\n\u003cli\u003eValerianova A, Mlcek M, Malik J, Grus T, Tejkl L, Kolosova B, et al. Comparing the hemodynamic effect of a large arteriovenous fistula during high and low cardiac output states. Front Physiol. 2023;14:1180224.\u003c/li\u003e\n\u003cli\u003ePark HS, Kang SH, Chung BH, Choi BS, Park CW, Yang CW, et al. Effect of intradialytic change in blood pressure and ultrafiltration volume on the variation in access flow measured by ultrasound dilution. Kidney Res Clin Pract. 2013;32:16\u0026ndash;20.\u003c/li\u003e\n\u003cli\u003eRonco C, Brendolan A, Crepaldi C, D\u0026rsquo;Intini V, Sergeyeva O, Levin NW. Noninvasive transcutaneous access flow measurement before and after hemodialysis: impact of hematocrit and blood pressure. Blood Purif. 2002;20:376\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eSands J, Glidden D, Miranda C. Access flow measured during hemodialysis. ASAIO J. 1996;42:M530-532.\u003c/li\u003e\n\u003cli\u003ePandeya S, Lindsay RM. The relationship between cardiac output and access flow during hemodialysis. ASAIO J. 1999;45:135\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eSpano S, Maeda A, Lam J, Chaba A, See E, Mount P, et al. Cardiac Output Changes during Renal Replacement Therapy: A Scoping Review. Blood Purif. 2023. https://doi.org/10.1159/000534601.\u003c/li\u003e\n\u003cli\u003eObokata M, Negishi K, Marwick TH, Kurosawa K, Ishida H, Ito K, et al. Comparison of different interdialytic intervals among hemodialysis patients on their echocardiogram-based cardiovascular parameters. Am Heart J. 2015;169:523-530.e2.\u003c/li\u003e\n\u003cli\u003eTsilonis K, Sarafidis PA, Kamperidis V, Loutradis C, Georgianos PI, Imprialos K, et al. Echocardiographic Parameters During Long and Short Interdialytic Intervals in Hemodialysis Patients. Am J Kidney Dis. 2016;68:772\u0026ndash;81.\u003c/li\u003e\n\u003cli\u003eLoutradis C, Sarafidis PA, Papadopoulos CE, Papagianni A, Zoccali C. The Ebb and Flow of Echocardiographic Cardiac Function Parameters in Relationship to Hemodialysis Treatment in Patients with ESRD. J Am Soc Nephrol. 2018;29:1372\u0026ndash;81.\u003c/li\u003e\n\u003cli\u003eVareesangthip K, Yincharoen P, Winijkul A, Chanchairujira T. Cardiac arrhythmia during early-week and mid-week dialysis in hemodialysis patients. Ther Apher Dial. 2021;25:890\u0026ndash;8.\u003c/li\u003e\n\u003cli\u003eUwumiro FE, Okpujie VO, Oyesomi A, Madu FC, Ilelaboye A, Shielu ML, et al. Weekend Effect on Mortality, Access to Renal Replacement Therapy, and Other Outcomes Among Patients With End-Stage Renal Disease: A Retrospective Analysis of the Nationwide Inpatient Sample. Cureus. 2023;15:e34139.\u003c/li\u003e\n\u003cli\u003eZhang H, Schaubel DE, Kalbfleisch JD, Bragg-Gresham JL, Robinson BM, Pisoni RL, et al. Dialysis outcomes and analysis of practice patterns suggests the dialysis schedule affects day-of-week mortality. Kidney Int. 2012;81:1108\u0026ndash;15.\u003c/li\u003e\n\u003cli\u003eFoley RN, Gilbertson DT, Murray T, Collins AJ. Long interdialytic interval and mortality among patients receiving hemodialysis. N Engl J Med. 2011;365:1099\u0026ndash;107.\u003c/li\u003e\n\u003cli\u003eGreen D, Roberts PR, New DI, Kalra PA. Sudden cardiac death in hemodialysis patients: an in-depth review. Am J Kidney Dis. 2011;57:921\u0026ndash;9.\u003c/li\u003e\n\u003cli\u003eFranczyk B, Gluba-Brz\u0026oacute;zka A, Bartnicki P, Rysz J. The occurrence of atrial fibrillation in dialysis patients and its association with left atrium volume before and after dialysis. Int Urol Nephrol. 2017;49:1071\u0026ndash;7.\u003c/li\u003e\n\u003cli\u003eFlythe JE, Liu S, Montez-Rath ME, Winkelmayer WC, Chang TI. Ultrafiltration rate and incident atrial fibrillation among older individuals initiating hemodialysis. Nephrol Dial Transplant. 2021;36:2084\u0026ndash;93.\u003c/li\u003e\n\u003cli\u003eBignotto LH, Kall\u0026aacute;s ME, Djouki RJT, Sassaki MM, Voss GO, Soto CL, et al. Electrocardiographic findings in chronic hemodialysis patients. J Bras Nefrol. 2012;34:235\u0026ndash;42.\u003c/li\u003e\n\u003cli\u003eJoki N, Tokumoto M, Takahashi N, Nishimura M. Current Perspectives on Sudden Cardiac Death in Hemodialysis Patients. Contrib Nephrol. 2018;196:5\u0026ndash;12.\u003c/li\u003e\n\u003cli\u003eOzportakal H, Ozkok A, Alkan O, Bulut AS, Boyraz M, Inanir M, et al. Hemodialysis-induced repolarization abnormalities on ECG are influenced by serum calcium levels and ultrafiltration volumes. Int Urol Nephrol. 2017;49:509\u0026ndash;15.\u003c/li\u003e\n\u003cli\u003eLyng Lindgren F, Tayal B, Bundgaard Ringgren K, Ascanius Jacobsen P, Hay Kragholm K, Zaremba T, et al. The variability of 2D and 3D transthoracic echocardiography applied in a general population : Intermodality, inter- and intraobserver variability. Int J Cardiovasc Imaging. 2022;38:2177\u0026ndash;90.\u003c/li\u003e\n\u003cli\u003eEsenboğa K, Kılı\u0026ccedil;kap M, Peker E, Kozluca V, Koca \u0026Ccedil;, Kaya CT, et al. Agreement between visually estimated left ventricular ejection fraction on echocardiography and quantitative measurements using cardiac magnetic resonance. Anatol J Cardiol. 2022;26:127\u0026ndash;32.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003eTable 1: Baseline patient characteristics. Mean, standard deviation and range or\u0026nbsp;absolute and relative frequency are given.\u0026nbsp;\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003eN=20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e8 (40%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eAge, years\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e53.7 (7.7), 41.0 to 67.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eHemodialysis vintage, months\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e49.0 (11.1), 33.0 to 72.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eBody mass index, kg/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e28.2 (3.8), 22.9 to 36.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eResidual diuresis, ml /\u0026nbsp;day\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e605 (256), 200 to 900\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eInterdialytic weight gain\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eabsolute, kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e3.2 (0.8), 1.9 to 4.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003erelative to dry weight, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e4.1 (0.8), 2.9 to 5.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eEffective dialysis time, minutes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e256.3 (5.3), 248.0 to 265.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eUltrafiltration rate, mL/min/kg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e0.159 (0.033), 0.110 to 0.195\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eHemodialysis modality\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003ehigh-flux dialysis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e15 (75%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003ehemodiafiltration\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e5 (25%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eSerum albumin, g/l\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e42.8 (3.2), 38.0 to 48.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eSerum sodium, mmol/l\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e139.6 (1.2), 138.0 to 141.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eDialysate / predialysis serum sodium gradient, mmol/l\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e0.1 (3.0), -4.0 to 4.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eCharlson comorbidity index, points\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e5.1 (1.6), 3.0 to 8.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eAVF (native)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eForearm, lower third\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e12 (60%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e8 (40%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eNYHA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eclass I\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e9 (45%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eclass II\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e11 (55%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003eAntihypertensive therapy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003enone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e3 (15%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003ebeta-blockers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e7 (35%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 63px;\"\u003e\n \u003cp\u003ebeta-blockers + angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 36px;\"\u003e\n \u003cp\u003e10 (50%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eTable 2: Dynamics of echocardiographic parameters\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003eBefore HD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003eAfter HD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eRaw mean difference\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e95% CI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eQa,\u0026nbsp;l/min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e1.4 (0,31), 1-2.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e1.3 (0.29). 0.95- 1.95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr; 0.12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e0.09;\u0026nbsp;0.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eCardiac output, l/min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e6.7 (1.5), 4.3-9.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e5 (1.3), 3.2-7.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr; 1.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e1.41;\u0026nbsp;2.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eCardiac index, l/min/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e3.5 (0.67), 2.27-4.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e2.6 (0.59), 1.6-4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr; 0.89\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e0.74; 1.03\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eCPR, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e21.3 (2.2), 17.5-27.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e26.4 (3.6), 20.8-31.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026uarr; 5.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e3.9; 6.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eCPR\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003e\u0026lt;20%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.002\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003e20%-29.9%\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003eNA\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003e\u0026ge;30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eEDV, ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e147 (26.0), 106-182\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e112.5 (19.6), 76-141\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr; 34.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e30.6;\u0026nbsp;38.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eEDV index, ml/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e76.6 (10.6), 58.8-96.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e58.6 (8.1), 42.1-73.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr;17.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e16.2, 19.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eESV, ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e56.9 (12.4), 31-79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e46.4 (10.0), 27-68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr; 10.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e8.9;\u0026nbsp;12.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eESV index, ml/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e29.7 (6), 17.8-41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e24.2 (4.8), 15.5-34.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr;5.49\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e4.67,\u0026nbsp;6.32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eEjection fraction, %\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e61.1 (6.6), 51.1-72.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e58.7 (6.4), 48.6-69.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr; 2.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e1.47; 3.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eHeart rate, beats per min\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e74.6 (7.6), 62-88\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e75.5 (7.9), 61-90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026uarr; 0.85\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e-1.22; 2.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eStroke volume, ml\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e90.1 (20.4), 65-132\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e66.2 (14.7), 42-95\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr; 24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e20.4;\u0026nbsp;27.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eStroke volume index, ml/m\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e46.9 (8.6), 34.3-62.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e34.5 (6.3), 23.3-48.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr;12.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e10.9, 14.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eSystolic BP, mmHg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e133 (15.1), 110-160\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e123.5 (10.5), 110-140\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr;9.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e3.48, 15.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.004\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eDiastolic BP, mmHg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e82.5 (10.2), 60-100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e77.5 (7.5), 60-90\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr;5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e-0.37; 10.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e0.066\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eMean BP, mmHg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e107.8 (12.0), 87.5-130\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e100.5 (8.3), 85-115\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr; 7.25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e2.02;\u0026nbsp;12.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e0.0\u003c/strong\u003e\u003cstrong\u003e09\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 104px;\"\u003e\n \u003cp\u003eePASP, mmHg\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 123px;\"\u003e\n \u003cp\u003e36.6 (9.1), 25-55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 151px;\"\u003e\n \u003cp\u003e29 (5.4), 22-42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 76px;\"\u003e\n \u003cp\u003e\u0026darr; 7.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e5.28;\u0026nbsp;9.92\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 85px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026lt;0.001\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"6\" style=\"width: 623px;\"\u003e\n \u003cp\u003eHD \u0026ndash; Hemodialysis,\u0026nbsp;\u003cbr\u003e\u0026nbsp;Qa \u0026ndash; AVF volume blood flow, CPR \u0026ndash; cardiopulmonary recirculation, EDV \u0026ndash; end-diastolic volume, ESV \u0026ndash; end-systolic volume, BP \u0026ndash; blood pressure, ePASP \u0026ndash; estimated pulmonary artery systolic pressure\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eTable 3: Association of nominal characteristics with the delta of the CPR. Mean, SD and range are given. T-test and analysis of variance were used to assess the significance of the association between cardio-fistula recirculation delta and categorical variables.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 38px;\"\u003e\n \u003cp\u003eCardiopulmonary recirculation\u0026nbsp;delta\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21px;\"\u003e\n \u003cp\u003eP value\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eSex\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 38px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e5.2 (3.2), 0.9-10.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 21px;\"\u003e\n \u003cp\u003e0.878\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e5.0 (2.4), 1.5-10.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eNYHA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 38px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e4.8 (2.3), 1.5- 9.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"2\" style=\"width: 21px;\"\u003e\n \u003cp\u003e0.642\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eII\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e5.4 (3.0), 0.9-10.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eTherapy\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 38px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd style=\"width: 21px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eNone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e2.6 (1.1), 1.5-3.6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd rowspan=\"3\" style=\"width: 21px;\"\u003e\n \u003cp\u003e0.122\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eBeta-blockers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e4.8 (2.7), 0.9-9.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd style=\"width: 39px;\"\u003e\n \u003cp\u003eBeta-blockers + Angiotensin-converting enzyme inhibitors / \u0026nbsp; \u0026nbsp; Angiotensin II receptor blockers\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 38px;\"\u003e\n \u003cp\u003e6.1 (2.6), 2.6-10.7\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Appendix","content":"\u003cp\u003eAppendix is not available with this version\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-nephrology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bnep","sideBox":"Learn more about [BMC Nephrology](http://bmcnephrol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bnep/default.aspx","title":"BMC Nephrology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"arteriovenous fistula, hemodialysis, cardiac output, heart failure, volume blood flow, cardiopulmonary recirculation","lastPublishedDoi":"10.21203/rs.3.rs-5635403/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5635403/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cem\u003eBackground.\u003c/em\u003e Cardiopulmonary recirculation (CPR) is a known risk factor for heart failure (HF). Typically, the assessment is performed on the interdialytic day. Hemodialysis (HD) sessions can induce significant hemodynamic changes, which may be important for patients with HF and preserved ejection fraction (EF), in whom the risk may be underestimated.\u003c/p\u003e \u003cp\u003e \u003cem\u003eObjective.\u003c/em\u003e To evaluate the dynamics of CPR due to a HD session following a long interdialytic gap in patients with HF and preserved EF.\u003c/p\u003e \u003cp\u003e \u003cem\u003eMethods.\u003c/em\u003e The prospective cohort single-arm study included 20 adult HD patients who met the inclusion criteria: EF\u0026thinsp;\u0026ge;\u0026thinsp;50%, NYHA I-II, AVF volume blood flow (Qa)\u0026thinsp;\u0026ge;\u0026thinsp;1 L/min, CPR\u0026thinsp;\u0026lt;\u0026thinsp;30%, interdialytic weight gain\u0026thinsp;\u0026lt;\u0026thinsp;5%, and eKt/V\u0026thinsp;\u0026gt;\u0026thinsp;1.2.\u003c/p\u003e \u003cp\u003eAll patients underwent transthoracic echocardiography on the third day after the previous HD session (Monday/Tuesday), 1 hour prior to and 2 hours after the session. In addition, the Qa of the brachial artery was measured. ClinicalTrials Id: NCT06394986 (May 01, 2024).\u003c/p\u003e \u003cp\u003e \u003cem\u003eResults.\u003c/em\u003e A reduction in cardiac preload after HD was evidenced by a decrease in the volume of cardiac chambers, as well as a reduction in pulmonary artery systolic pressure and arterial blood pressure. The EF and Qa slightly decreased (2.46% [95% CI 1.47; 3.45], p\u0026thinsp;\u0026lt;\u0026thinsp;0.001 and 0.12 l/min [95% CI 0.09; 0.14], p\u0026thinsp;\u0026lt;\u0026thinsp;0.001, respectively), whereas cardiac output decreased significantly (1.71 L/min [95% CI 0.8; 2.6], p\u0026thinsp;\u0026lt;\u0026thinsp;0.001). This led to an increase in CPR of 5.1% [95% CI 3.9; 6.4], p\u0026thinsp;\u0026lt;\u0026thinsp;0.001. As a result, in 5 patients, the CPR exceeded 30% after HD.\u003c/p\u003e \u003cp\u003eIn the sensitivity analysis, no parameters significantly associated with the variance CPR were identified.\u003c/p\u003e \u003cp\u003e \u003cem\u003eConclusions.\u003c/em\u003e Some patients experience a significant increase in CPR after HD. However, the prognostic value of this phenomenon remains unclear. For patients with HF and normal or subnormal CPR measured on the interdialytic day, it is advisable to determine the CPR shortly after HD. This may serve as a 'stress test' to identify hidden hemodynamic disorders and manifest the cardiotoxic effect of AVF.\u003c/p\u003e","manuscriptTitle":"Cardiopulmonary recirculation in patients with chronic heart failure and preserved left ventricular ejection fraction: the \"Monday Morning Phenomenon\"","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-12-25 15:30:32","doi":"10.21203/rs.3.rs-5635403/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-07T14:25:31+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-07T04:53:33+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-06T19:52:54+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-06-28T01:30:41+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"228077959362715757897110548841029171992","date":"2025-06-26T11:57:01+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"189230153954013802633860449050372935603","date":"2025-06-25T22:34:32+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"154016002605921113444089333170416937707","date":"2025-06-23T18:37:00+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"52427687093385021233100417513095243371","date":"2025-06-23T02:16:18+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-02-13T21:42:38+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"234508092067688469902587482416388661175","date":"2025-02-05T20:51:24+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-01-24T07:15:27+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2024-12-19T07:55:18+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-12-18T13:54:14+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2024-12-18T13:53:45+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Nephrology","date":"2024-12-13T04:25:53+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-nephrology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bnep","sideBox":"Learn more about [BMC Nephrology](http://bmcnephrol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bnep/default.aspx","title":"BMC Nephrology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e78450b6-4fc7-4a67-ba1b-abdfe788e51f","owner":[],"postedDate":"December 25th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-09-08T15:59:16+00:00","versionOfRecord":{"articleIdentity":"rs-5635403","link":"https://doi.org/10.1186/s12882-025-04431-6","journal":{"identity":"bmc-nephrology","isVorOnly":false,"title":"BMC Nephrology"},"publishedOn":"2025-09-01 15:57:10","publishedOnDateReadable":"September 1st, 2025"},"versionCreatedAt":"2024-12-25 15:30:32","video":"","vorDoi":"10.1186/s12882-025-04431-6","vorDoiUrl":"https://doi.org/10.1186/s12882-025-04431-6","workflowStages":[]},"version":"v1","identity":"rs-5635403","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5635403","identity":"rs-5635403","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}