Early Outcomes and Predictors of In-Hospital Mortality After Redo Cardiac Surgery: Impact of Combined Procedures

Early Outcomes and Predictors of In-Hospital Mortality After Redo Cardiac Surgery: Impact of Combined Procedures | 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 Early Outcomes and Predictors of In-Hospital Mortality After Redo Cardiac Surgery: Impact of Combined Procedures mohammad alsalaldeh This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9076756/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 20 You are reading this latest preprint version Abstract Background: Redo cardiac surgery is being performed more frequently as survival after initial cardiac operations continues to improve. However, repeat procedures remain technically demanding and carry higher perioperative risk, particularly when additional combined interventions are required. Methods: We conducted a retrospective observational study including 114 patients who underwent redo cardiac surgery between January 2010 and December 2023. Patients were divided into isolated redo procedures (n=68) and combined redo procedures (n=46). The primary outcome was in-hospital mortality, and early survival was assessed using the Kaplan–Meier method. Results: Compared with isolated redo surgery, combined redo procedures were associated with longer cardiopulmonary bypass and aortic cross-clamp times, increased postoperative drainage, longer ventilation duration, and a longer hospital stay. In-hospital mortality was significantly higher in the combined group (32.6% vs. 13.2%). On multivariable analysis, combined redo surgery remained an independent predictor of in-hospital mortality (OR 3.1, 95% CI 1.4–6.9; p=0.004). Mortality was also associated with cardiopulmonary bypass time ≥180 minutes (OR 2.4, 95% CI 1.1–5.3; p=0.021) and poorer functional status (NYHA class III–IV) (OR 2.0, 95% CI 1.0–4.1; p=0.048). Kaplan–Meier analysis demonstrated reduced early survival after combined redo surgery. Conclusions: Combined procedures during redo cardiac surgery are associated with higher early mortality and lower early survival, underscoring the importance of careful patient selection and preoperative risk stratification. Redo cardiac surgery Combined procedures Early outcomes In-hospital mortality Kaplan–Meier survival Figures Figure 1 Introduction This has resulted in improved survival after the initial operations. However, with the passage of time, an increasing number of these survivors are presenting with progressive coronary or valvular disease and are undergoing redo operations. More contemporary reports suggest that redo operations are an increasing portion of the workload of adult cardiac surgeons and are associated with a higher mortality than the initial operations.¹-³ Redo cardiac surgery is often complicated by several technical and physiological challenges. These include the need for resternotomies, the presence of dense mediastinal adhesions, altered cardiac anatomy, and the presence of patent bypass grafts, which often contribute to long cardiopulmonary and aortic cross-clamp times. These have been consistently implicated in contributing to early postoperative complications and mortality.¹,²,⁶ The complexity of redo procedures is further compounded in the context of the requirement for combined procedures. Patients undergoing redo procedures often have co-existent coronary artery disease and valvular disease; hence, the requirement for combined procedures such as CABG and valvular procedures or multiple valvular procedures arises. Combined procedures in the context of primary procedures are known to be associated with an increased risk of operation as compared to isolated procedures.⁴,⁵ However, literature addressing the issue of increased risk in the context of redo procedures is scarce.¹¹,¹² Prolonged cardiopulmonary bypass is recognized as an established predictor of post-operative morbidity and mortality following cardiac surgery, particularly when the procedure is technically demanding.⁷,⁸ In the context of redo procedures, the duration of bypass is commonly increased, which can have implications in relation to other patient factors, including the presence of severe pre-operative functional limitation and reduced ventricular reserve, as these have also been included in the risk stratification models.⁹,¹⁰ The issue of the relative contributions of the complexity of the procedure and the patient is of interest. Thus, the present study sought to assess the effect of combined surgical procedures on the early results after redo cardiac surgery, as well as the predictors of in-hospital mortality. In addition, the early survival results were also analyzed using the Kaplan-Meier method, which helps describe the time course of the risk.¹³,¹⁴ Methods Study Design and Patient Population The study is a retrospective observational study that was conducted in a tertiary referral center, where adult patients who have undergone redo cardiac surgery between January 2010 to December 2023 were enrolled in the study. The study defined redo cardiac surgery as “any cardiac surgical procedure performed after an individual has undergone an operation requiring resternotomy, where the resternotomy is performed on a patient who is an adult.” The study enrolled a total of 137 adult patients who have undergone either an isolated redo procedure or a combination procedure during the study period. After the exclusion criteria, a total of 114 adult patients were enrolled in the study. Ethical Considerations The study has been approved by the institutional ethics committee (approval date: December 10, 2024; approval no: 21), and the study has been carried out in accordance with the guidelines of the Declaration of Helsinki. As this study has a retrospective study design and uses anonymized information, consent from participants has not been required.. Definitions and Grouping The study subjects were divided into two groups based on the redo procedure that was done. Isolated redo surgery refers to the performance of a solitary cardiac surgery procedure such as isolated coronary bypass grafting and isolated valve procedures. Combined redo surgery refers to the simultaneous performance of two or more cardiac surgery procedures such as coronary bypass grafting with valve procedures and multiple valve procedures. Data Collection Demographic characteristics, comorbidities, and preoperative clinical risk variables were collected retrospectively from institutional electronic medical records using a pre-specified data extraction tool. Preoperative functional status was collected using the New York Heart Association functional classification system. Preoperative left ventricular ejection fraction values were collected from preoperative transthoracic echocardiograms. The operative variables included cardiopulmonary bypass time and aortic cross-clamp time. The early postoperative outcomes included postoperative drainage volume, mechanical ventilation time, hospital stay, and in-hospital mortality. Outcome Measures The principal outcome of interest was in-hospital mortality, which was defined as deaths that occurred during the initial hospital stay. Secondary outcome measures were operative and postoperative measures. Kaplan–Meier estimates of early survival were performed based on days from surgery to death or discharge; discharge was considered a censoring event. Statistical Analysis For continuous variables, the data is expressed as mean and standard deviation and compared by either the Student's t-test or the Mann-Whitney U-test as necessary. Categorical variables will be expressed as counts and percentages and compared by either the Chi-square test or Fisher's exact test as necessary.Multivariable logistic regression analysis was conducted to evaluate independent predictors for in-hospital mortality. The variables included in the multivariable model were based upon clinical importance and had a univariable p-value < 0.10. The results are expressed as odds ratios with 95% confidence intervals. Multicollinearity was checked before constructing the multivariable model. The Kaplan-Meier curves were compared using the log-rank test. A p-value < 0.05 was considered statistically significant for all calculations. All calculations were done using SPSS (IBM Corporation, Armonk, USA). Results Patient Characteristics A total of 114 redo cardiac surgical cases were included for the final analysis. The baseline demographic and clinical characteristics of the study participants are described in Table 1 . The study found that the mean age of the participants who underwent combined redo procedures was older compared to the group who underwent isolated redo procedures. The study also found that the participants who underwent combined redo procedures were more likely to have chronic obstructive pulmonary disease, advanced functional status, and lower LVEF. Table 1 Baseline Characteristics of Patients Undergoing Redo Cardiac Surgery Variable Overall (n = 114) Isolated Redo (n = 68) Combined Redo (n = 46) p value Age, years (mean ± SD) 57.2 ± 10.8 55.1 ± 10.2 60.3 ± 11.1 0.021 Male sex, n (%) 76 (66.7) 42 (61.8) 34 (73.9) 0.19 Diabetes mellitus, n (%) 39 (34.2) 20 (29.4) 19 (41.3) 0.18 Hypertension, n (%) 75 (65.8) 41 (60.3) 34 (73.9) 0.14 COPD, n (%) 21 (18.4) 9 (13.2) 12 (26.1) 0.048 Chronic renal failure, n (%) 6 (5.3) 2 (2.9) 4 (8.7) 0.21 NYHA class III–IV, n (%) 48 (42.1) 22 (32.4) 26 (56.5) 0.009 Ejection fraction, % (mean ± SD) 50.0 ± 9.7 52.3 ± 8.9 46.8 ± 10.1 0.006 Operative and Early Postoperative Outcomes Results for operative characteristics and early postoperative outcomes are shown in Table 2 . The cardiopulmonary bypass and aortic cross-clamp times were longer in the combined redo group compared to the isolated redo group. The postoperative drainage volumes, ventilation times, and length of stay were higher in the combined redo group compared to the isolated redo group. Table 2 Operative and Early Postoperative Outcomes Variable Overall (n = 114) Isolated Redo (n = 68) Combined Redo (n = 46) p value CPB time, min (mean ± SD) 187.5 ± 82.0 158.4 ± 61.7 229.6 ± 79.4 < 0.001 Cross-clamp time, min (mean ± SD) 113.4 ± 51.2 94.6 ± 39.1 141.2 ± 55.3 < 0.001 Ventilation time, hours (mean ± SD) 23.4 ± 38.0 16.8 ± 22.4 33.1 ± 48.6 0.041 Drainage volume, mL (mean ± SD) 634 ± 466 512 ± 321 814 ± 572 0.006 Hospital stay, days (mean ± SD) 16.1 ± 6.5 14.2 ± 5.1 18.9 ± 7.2 < 0.001 In-hospital mortality, n (%) 24 (21.1) 9 (13.2) 15 (32.6) 0.014 Mortality in the hospital was found to be significantly higher in patients who underwent combined redo surgery than in those who underwent isolated redo surgery (32.6% vs 13.2%, p = 0.014) (Table 2 ). Early Survival Analysis Early survival was analyzed in redo heart surgery patients using Kaplan-Meier analysis (Fig. 1 ). Patients who underwent redo heart surgeries in combination had lower early survival rates compared to those who underwent isolated redo heart surgeries. The separation in the Kaplan-Meier curves occurred early in the postoperative period, and the difference was statistically significant at p < 0.05. Patients who were discharged were censored. Predictors of In-Hospital Mortality The independent predictors for in-hospital mortality are presented in Table 3 . Combined redo surgery was an independent predictor for in-hospital mortality after adjusting for other covariates, and the odds ratio was 3.1 (95% CI 1.4 to 6.9; p = 0.004). A prolonged cardiopulmonary bypass time (> 180 minutes) was also an independent predictor for mortality after adjusting for other covariates, and the odds ratio was 2.4 (95% CI 1.1 to 5.3; p = 0.021). Advanced functional class was also an independent predictor for mortality after adjusting for other covariates, and the odds ratio was 2.0 (95% CI 1.0 to 4.1; p = 0.048). Reduced left ventricular ejection fraction was a trend for mortality but did not quite reach statistical significance. Table 3 Multivariable Logistic Regression Analysis for In-Hospital Mortality Variable Odds Ratio 95% CI p value Combined redo procedure 3.1 1.4–6.9 0.004 CPB time > 180 min 2.4 1.1–5.3 0.021 NYHA class III–IV 2.0 1.0–4.1 0.048 EF < 40% 1.8 0.9–3.8 0.087 Footnote: Variables entered into the multivariable model were selected based on clinical relevance and univariable p < 0.10. Discussion The results of the present study reveal the association of combined surgical procedures with increased risk of early mortality and decreased survival during the initial postoperative period of redo cardiac surgeries. Combined redo surgeries were associated with substantially increased risk of adverse outcomes during the initial postoperative period when compared to isolated redo surgeries, even when adjusting for clinically relevant risk factors. This may highlight the role of procedural complexity in the risk of adverse outcomes during the initial postoperative period.¹¹,¹²Redo cardiac surgeries are always challenging due to the factors of resternotomies, mediastinal adhesions, changed anatomy, and presence of a PFG. These factors usually resulted in an extended cardiopulmonary bypass time and aortic cross-clamp time, which were consistently associated with worse early outcomes. Prolonged cardiopulmonary bypass time was found to be an independent predictor of in-hospital mortality in the current study, emphasizing its status as a predictor of operative complexity and physiological stress. The incremental risk associated with the combination of redo procedures is clinically significant. Patients who require redo procedures frequently have coexisting coronary and valvular diseases, thereby necessitating multiple procedures within the same operation. Combined procedures have previously been documented to increase the risk of mortality during primary cardiac surgical procedures.⁴,⁵ However, the impact of the combination of redo procedures on mortality risk has not previously been well documented.¹¹,¹² The results of the study expand on previous knowledge by showing the impact of the combination of redo procedures on the risk of mortality during redo cardiac surgical procedures.Functional status was also an important determinant in the early outcome measures. Advanced NYHA functional class was independently related with in-hospital mortality rates, possibly because patients with poorer functional status have lesser physiological reserve or tolerance to the perioperative strain of complex redo procedures. This is supported by existing cardiac surgery risk algorithms that list functional status as a major predictor of perioperative risk.⁹,¹⁰ Early survival analysis further clarified the temporal pattern of risk. Kaplan–Meier curves demonstrated early separation between combined and isolated redo groups, indicating that the excess risk associated with combined procedures manifests predominantly during the immediate postoperative period. Early survival analysis is particularly relevant in redo populations, where early postoperative events largely determine overall prognosis.¹³,¹⁴ From a clinical standpoint, the results support a judicious approach to the patient group that requires a combination of redo cardiac surgery. While the combination of operations cannot always be avoided in a selected group of patients, the risk associated with the combination should always be taken into consideration. In selected high-risk patients, other approaches that are less invasive or staged may also be considered.¹¹,¹²There were several limitations to the study, including the following: the retrospective single-institution study limits the generalizability of the results, as well as the fact that confounding variables cannot be fully controlled despite adjustment. Another limitation is the fact that the results only measured the short-term outcomes, while long-term survival was not evaluated. However, short-term outcomes were particularly relevant to the setting of redo cardiac surgery, while the consistency of the results across the different analyses supports the validity of the observed associations.¹¹,¹² In conclusion, combined procedures are independently linked to increased early mortality and reduced early survival after redo cardiac surgery. Procedural complexity, cardiopulmonary bypass times, and functional limitations are important predictors of early outcome after combined procedures. Careful patient selection and meticulous planning of combined procedures are essential to optimize outcome in this high-risk population.¹–³,⁷–¹² Conclusion Simultaneous surgery has an independent association with increased mortality and decreased survival in the early period following redo surgery. The complexity of the surgery, the cardiopulmonary bypass times, and the functional limitations are major factors that contribute to the risk in the perioperative period. These factors are critical and need to be taken into consideration in the perioperative period. Limitations There are some limitations in this study. For one, the design of the study being retrospective in nature limits the external validity of the data presented in this paper. Second, the focus of the data was only on early in-hospital complications, while long-term survival was not measured in this paper. Third, the perioperative care strategy used in the management of patients with AMI has changed over the long period of the study, which could have affected the early outcome of the patients in this series. Declarations Funding The authors declare that no external funding was received for this study. Conflict of Interest: The authors declare no conflicts of interest related to this work. Data Availability: The data that support the findings of this study are available from the corresponding author upon reasonable request. Data Availability Statement : All data supporting the findings of this study are available without restriction. The data are stored in the university hospital patient database and can be provided by the corresponding authors upon reasonable request. Declaration of Conflicting Interests : The authors declare that there are no conflicts of interest related to the authorship or publication of this study. Funding : This research received no specific grant or financial support for the conduct of the study or the preparation of this manuscript. Ethics Committee Approval : The study was approved by the Institutional Medical Ethics Committee and conducted in accordance with the principles of the Declaration of Helsinki (Approval No: E-60116787-020-622743). Author Contribution All authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by the authors. The first draft of the manuscript was written by the authors, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript. References LaPar DJ, Ailawadi G, Isbell JM, et al. Outcomes of reoperative cardiac surgery in the modern era. Ann Thorac Surg. 2012;94(2):458–64. Roselli EE, Pettersson GB, Blackstone EH. Reoperative cardiac surgery: challenges and outcomes. J Thorac Cardiovasc Surg. 2010;140(3):598–603. Jones JM, O’Kane H, Gladstone DJ, et al. Repeat heart valve surgery: risk factors for operative mortality. Heart. 2001;85(6):633–7. Fukui T, Takanashi S, Hosoda Y. Impact of combined valve and coronary procedures on operative mortality. Eur J Cardiothorac Surg. 2013;44(6):e296–302. Gammie JS, Sheng S, Griffith BP, et al. Trends in mitral valve surgery in the United States: outcomes of isolated versus combined procedures. Circulation. 2009;120(11 Suppl):S124–30. Jamieson WR, Burr LH, Miyagishima RT, et al. Reoperation for cardiac valvular disease: risk assessment. J Thorac Cardiovasc Surg. 2003;126(3):681–90. Ranucci M, Castelvecchio S, Menicanti L, et al. Cardiopulmonary bypass duration and postoperative mortality. J Thorac Cardiovasc Surg. 2012;144(4):875–81. Al-Sarraf N, Thalib L, Hughes A, et al. Cross-clamp time and postoperative outcomes in cardiac surgery. Eur J Cardiothorac Surg. 2011;39(1):e24–30. Nashef SA, Roques F, Sharples LD, et al. EuroSCORE II. Eur J Cardiothorac Surg. 2012;41(4):734–44. Shahian DM, O’Brien SM, Filardo G, et al. The Society of Thoracic Surgeons 2008 cardiac surgery risk models. Ann Thorac Surg. 2009;88(1 Suppl):S2–22. Filsoufi F, Rahmanian PB, Castillo JG, et al. Early outcomes of reoperative cardiac surgery. Ann Thorac Surg. 2006;82(3):803–10. Benedetto U, Melina G, Angeloni E, et al. Predictors of early mortality after redo cardiac surgery. J Thorac Cardiovasc Surg. 2014;148(5):2206–12. Altman DG, Bland JM. Time to event analyses: survival analysis. BMJ. 1998;317:468–9. Bradburn MJ, Clark TG, Love SB, et al. Survival analysis methods in medical research. Br J Cancer. 2003;89(2):232–8. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 29 Apr, 2026 Reviews received at journal 25 Apr, 2026 Reviews received at journal 23 Apr, 2026 Reviews received at journal 22 Apr, 2026 Reviews received at journal 21 Apr, 2026 Reviews received at journal 18 Apr, 2026 Reviewers agreed at journal 15 Apr, 2026 Reviews received at journal 15 Apr, 2026 Reviewers agreed at journal 14 Apr, 2026 Reviewers agreed at journal 14 Apr, 2026 Reviewers agreed at journal 14 Apr, 2026 Reviewers agreed at journal 14 Apr, 2026 Reviewers agreed at journal 12 Apr, 2026 Reviewers agreed at journal 08 Apr, 2026 Reviewers agreed at journal 07 Apr, 2026 Reviewers invited by journal 07 Apr, 2026 Editor invited by journal 18 Mar, 2026 Editor assigned by journal 16 Mar, 2026 Submission checks completed at journal 16 Mar, 2026 First submitted to journal 09 Mar, 2026 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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Patients undergoing combined redo surgery showed significantly reduced early survival compared with those undergoing isolated redo surgery (log-rank test, p \u0026lt; 0.05). Discharge was treated as a censored event.\u003c/p\u003e","description":"","filename":"floatimage1.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-9076756/v1/f0aa71d3ed5d1d789493c3de.jpeg"},{"id":106973619,"identity":"71b4985c-3cdd-4304-be9d-0c213d76a911","added_by":"auto","created_at":"2026-04-15 10:28:30","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":760596,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9076756/v1/3db61147-0b48-46f8-ad55-11f815ec51ae.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Early Outcomes and Predictors of In-Hospital Mortality After Redo Cardiac Surgery: Impact of Combined Procedures","fulltext":[{"header":"Introduction","content":"\u003cp\u003eThis has resulted in improved survival after the initial operations. However, with the passage of time, an increasing number of these survivors are presenting with progressive coronary or valvular disease and are undergoing redo operations. More contemporary reports suggest that redo operations are an increasing portion of the workload of adult cardiac surgeons and are associated with a higher mortality than the initial operations.\u0026sup1;-\u0026sup3;\u003c/p\u003e \u003cp\u003eRedo cardiac surgery is often complicated by several technical and physiological challenges. These include the need for resternotomies, the presence of dense mediastinal adhesions, altered cardiac anatomy, and the presence of patent bypass grafts, which often contribute to long cardiopulmonary and aortic cross-clamp times. These have been consistently implicated in contributing to early postoperative complications and mortality.\u0026sup1;,\u0026sup2;,⁶\u003c/p\u003e \u003cp\u003eThe complexity of redo procedures is further compounded in the context of the requirement for combined procedures. Patients undergoing redo procedures often have co-existent coronary artery disease and valvular disease; hence, the requirement for combined procedures such as CABG and valvular procedures or multiple valvular procedures arises. Combined procedures in the context of primary procedures are known to be associated with an increased risk of operation as compared to isolated procedures.⁴,⁵ However, literature addressing the issue of increased risk in the context of redo procedures is scarce.\u0026sup1;\u0026sup1;,\u0026sup1;\u0026sup2;\u003c/p\u003e \u003cp\u003eProlonged cardiopulmonary bypass is recognized as an established predictor of post-operative morbidity and mortality following cardiac surgery, particularly when the procedure is technically demanding.⁷,⁸ In the context of redo procedures, the duration of bypass is commonly increased, which can have implications in relation to other patient factors, including the presence of severe pre-operative functional limitation and reduced ventricular reserve, as these have also been included in the risk stratification models.⁹,\u0026sup1;⁰ The issue of the relative contributions of the complexity of the procedure and the patient is of interest.\u003c/p\u003e \u003cp\u003eThus, the present study sought to assess the effect of combined surgical procedures on the early results after redo cardiac surgery, as well as the predictors of in-hospital mortality. In addition, the early survival results were also analyzed using the Kaplan-Meier method, which helps describe the time course of the risk.\u0026sup1;\u0026sup3;,\u0026sup1;⁴\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eStudy Design and Patient Population\u003c/h2\u003e \u003cp\u003eThe study is a retrospective observational study that was conducted in a tertiary referral center, where adult patients who have undergone redo cardiac surgery between January 2010 to December 2023 were enrolled in the study. The study defined redo cardiac surgery as \u0026ldquo;any cardiac surgical procedure performed after an individual has undergone an operation requiring resternotomy, where the resternotomy is performed on a patient who is an adult.\u0026rdquo; The study enrolled a total of 137 adult patients who have undergone either an isolated redo procedure or a combination procedure during the study period. After the exclusion criteria, a total of 114 adult patients were enrolled in the study.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eEthical Considerations\u003c/h3\u003e\n\u003cp\u003eThe study has been approved by the institutional ethics committee (approval date: December 10, 2024; approval no: 21), and the study has been carried out in accordance with the guidelines of the Declaration of Helsinki. As this study has a retrospective study design and uses anonymized information, consent from participants has not been required..\u003c/p\u003e\n\u003ch3\u003eDefinitions and Grouping\u003c/h3\u003e\n\u003cp\u003eThe study subjects were divided into two groups based on the redo procedure that was done. Isolated redo surgery refers to the performance of a solitary cardiac surgery procedure such as isolated coronary bypass grafting and isolated valve procedures. Combined redo surgery refers to the simultaneous performance of two or more cardiac surgery procedures such as coronary bypass grafting with valve procedures and multiple valve procedures.\u003c/p\u003e\n\u003ch3\u003eData Collection\u003c/h3\u003e\n\u003cp\u003eDemographic characteristics, comorbidities, and preoperative clinical risk variables were collected retrospectively from institutional electronic medical records using a pre-specified data extraction tool. Preoperative functional status was collected using the New York Heart Association functional classification system. Preoperative left ventricular ejection fraction values were collected from preoperative transthoracic echocardiograms.\u003c/p\u003e \u003cp\u003eThe operative variables included cardiopulmonary bypass time and aortic cross-clamp time. The early postoperative outcomes included postoperative drainage volume, mechanical ventilation time, hospital stay, and in-hospital mortality.\u003c/p\u003e\n\u003ch3\u003eOutcome Measures\u003c/h3\u003e\n\u003cp\u003eThe principal outcome of interest was in-hospital mortality, which was defined as deaths that occurred during the initial hospital stay. Secondary outcome measures were operative and postoperative measures. Kaplan\u0026ndash;Meier estimates of early survival were performed based on days from surgery to death or discharge; discharge was considered a censoring event.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eFor continuous variables, the data is expressed as mean and standard deviation and compared by either the Student's t-test or the Mann-Whitney U-test as necessary. Categorical variables will be expressed as counts and percentages and compared by either the Chi-square test or Fisher's exact test as necessary.Multivariable logistic regression analysis was conducted to evaluate independent predictors for in-hospital mortality. The variables included in the multivariable model were based upon clinical importance and had a univariable p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.10. The results are expressed as odds ratios with 95% confidence intervals. Multicollinearity was checked before constructing the multivariable model. The Kaplan-Meier curves were compared using the log-rank test. A p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant for all calculations. All calculations were done using SPSS (IBM Corporation, Armonk, USA).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003ePatient Characteristics\u003c/h2\u003e \u003cp\u003eA total of 114 redo cardiac surgical cases were included for the final analysis. The baseline demographic and clinical characteristics of the study participants are described in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The study found that the mean age of the participants who underwent combined redo procedures was older compared to the group who underwent isolated redo procedures. The study also found that the participants who underwent combined redo procedures were more likely to have chronic obstructive pulmonary disease, advanced functional status, and lower LVEF.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eBaseline Characteristics of Patients Undergoing Redo Cardiac Surgery\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eOverall (n\u0026thinsp;=\u0026thinsp;114)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eIsolated Redo (n\u0026thinsp;=\u0026thinsp;68)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eCombined Redo (n\u0026thinsp;=\u0026thinsp;46)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003ep value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAge, years (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e57.2\u0026thinsp;\u0026plusmn;\u0026thinsp;10.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e55.1\u0026thinsp;\u0026plusmn;\u0026thinsp;10.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e60.3\u0026thinsp;\u0026plusmn;\u0026thinsp;11.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.021\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eMale sex, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e76 (66.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e42 (61.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e34 (73.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eDiabetes mellitus, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e39 (34.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20 (29.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e19 (41.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eHypertension, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e75 (65.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e41 (60.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e34 (73.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.14\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eCOPD, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21 (18.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e9 (13.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e12 (26.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.048\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eChronic renal failure, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6 (5.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2 (2.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 (8.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.21\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNYHA class III\u0026ndash;IV, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e48 (42.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e22 (32.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e26 (56.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.009\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eEjection fraction, % (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e50.0\u0026thinsp;\u0026plusmn;\u0026thinsp;9.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e52.3\u0026thinsp;\u0026plusmn;\u0026thinsp;8.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e46.8\u0026thinsp;\u0026plusmn;\u0026thinsp;10.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.006\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eOperative and Early Postoperative Outcomes\u003c/h2\u003e \u003cp\u003eResults for operative characteristics and early postoperative outcomes are shown in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The cardiopulmonary bypass and aortic cross-clamp times were longer in the combined redo group compared to the isolated redo group. The postoperative drainage volumes, ventilation times, and length of stay were higher in the combined redo group compared to the isolated redo group.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eOperative and Early Postoperative Outcomes\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003eOverall (n\u0026thinsp;=\u0026thinsp;114)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eIsolated Redo (n\u0026thinsp;=\u0026thinsp;68)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eCombined Redo (n\u0026thinsp;=\u0026thinsp;46)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003ep value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCPB time, min (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003e187.5\u0026thinsp;\u0026plusmn;\u0026thinsp;82.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e158.4\u0026thinsp;\u0026plusmn;\u0026thinsp;61.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e229.6\u0026thinsp;\u0026plusmn;\u0026thinsp;79.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCross-clamp time, min (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003e113.4\u0026thinsp;\u0026plusmn;\u0026thinsp;51.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e94.6\u0026thinsp;\u0026plusmn;\u0026thinsp;39.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e141.2\u0026thinsp;\u0026plusmn;\u0026thinsp;55.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVentilation time, hours (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003e23.4\u0026thinsp;\u0026plusmn;\u0026thinsp;38.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e16.8\u0026thinsp;\u0026plusmn;\u0026thinsp;22.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e33.1\u0026thinsp;\u0026plusmn;\u0026thinsp;48.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.041\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrainage volume, mL (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003e634\u0026thinsp;\u0026plusmn;\u0026thinsp;466\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e512\u0026thinsp;\u0026plusmn;\u0026thinsp;321\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e814\u0026thinsp;\u0026plusmn;\u0026thinsp;572\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.006\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHospital stay, days (mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003e16.1\u0026thinsp;\u0026plusmn;\u0026thinsp;6.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14.2\u0026thinsp;\u0026plusmn;\u0026thinsp;5.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e18.9\u0026thinsp;\u0026plusmn;\u0026thinsp;7.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIn-hospital mortality, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003e24 (21.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e9 (13.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e15 (32.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.014\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eMortality in the hospital was found to be significantly higher in patients who underwent combined redo surgery than in those who underwent isolated redo surgery (32.6% vs 13.2%, p\u0026thinsp;=\u0026thinsp;0.014) (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eEarly Survival Analysis\u003c/h2\u003e \u003cp\u003eEarly survival was analyzed in redo heart surgery patients using Kaplan-Meier analysis (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Patients who underwent redo heart surgeries in combination had lower early survival rates compared to those who underwent isolated redo heart surgeries. The separation in the Kaplan-Meier curves occurred early in the postoperative period, and the difference was statistically significant at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05. Patients who were discharged were censored.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003ePredictors of In-Hospital Mortality\u003c/h2\u003e \u003cp\u003eThe independent predictors for in-hospital mortality are presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. Combined redo surgery was an independent predictor for in-hospital mortality after adjusting for other covariates, and the odds ratio was 3.1 (95% CI 1.4 to 6.9; p\u0026thinsp;=\u0026thinsp;0.004). A prolonged cardiopulmonary bypass time (\u0026gt;\u0026thinsp;180 minutes) was also an independent predictor for mortality after adjusting for other covariates, and the odds ratio was 2.4 (95% CI 1.1 to 5.3; p\u0026thinsp;=\u0026thinsp;0.021). Advanced functional class was also an independent predictor for mortality after adjusting for other covariates, and the odds ratio was 2.0 (95% CI 1.0 to 4.1; p\u0026thinsp;=\u0026thinsp;0.048). Reduced left ventricular ejection fraction was a trend for mortality but did not quite reach statistical significance.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eMultivariable Logistic Regression Analysis for In-Hospital Mortality\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVariable\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOdds Ratio\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003ep value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCombined redo procedure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.4\u0026ndash;6.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCPB time\u0026thinsp;\u0026gt;\u0026thinsp;180 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.1\u0026ndash;5.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.021\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNYHA class III\u0026ndash;IV\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.0\u0026ndash;4.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.048\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEF\u0026thinsp;\u0026lt;\u0026thinsp;40%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.9\u0026ndash;3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.087\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eFootnote: Variables entered into the multivariable model were selected based on clinical relevance and univariable p\u0026thinsp;\u0026lt;\u0026thinsp;0.10.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe results of the present study reveal the association of combined surgical procedures with increased risk of early mortality and decreased survival during the initial postoperative period of redo cardiac surgeries. Combined redo surgeries were associated with substantially increased risk of adverse outcomes during the initial postoperative period when compared to isolated redo surgeries, even when adjusting for clinically relevant risk factors. This may highlight the role of procedural complexity in the risk of adverse outcomes during the initial postoperative period.\u0026sup1;\u0026sup1;,\u0026sup1;\u0026sup2;Redo cardiac surgeries are always challenging due to the factors of resternotomies, mediastinal adhesions, changed anatomy, and presence of a PFG. These factors usually resulted in an extended cardiopulmonary bypass time and aortic cross-clamp time, which were consistently associated with worse early outcomes. Prolonged cardiopulmonary bypass time was found to be an independent predictor of in-hospital mortality in the current study, emphasizing its status as a predictor of operative complexity and physiological stress.\u003c/p\u003e \u003cp\u003eThe incremental risk associated with the combination of redo procedures is clinically significant. Patients who require redo procedures frequently have coexisting coronary and valvular diseases, thereby necessitating multiple procedures within the same operation. Combined procedures have previously been documented to increase the risk of mortality during primary cardiac surgical procedures.⁴,⁵ However, the impact of the combination of redo procedures on mortality risk has not previously been well documented.\u0026sup1;\u0026sup1;,\u0026sup1;\u0026sup2; The results of the study expand on previous knowledge by showing the impact of the combination of redo procedures on the risk of mortality during redo cardiac surgical procedures.Functional status was also an important determinant in the early outcome measures. Advanced NYHA functional class was independently related with in-hospital mortality rates, possibly because patients with poorer functional status have lesser physiological reserve or tolerance to the perioperative strain of complex redo procedures. This is supported by existing cardiac surgery risk algorithms that list functional status as a major predictor of perioperative risk.⁹,\u0026sup1;⁰\u003c/p\u003e \u003cp\u003eEarly survival analysis further clarified the temporal pattern of risk. Kaplan\u0026ndash;Meier curves demonstrated early separation between combined and isolated redo groups, indicating that the excess risk associated with combined procedures manifests predominantly during the immediate postoperative period. Early survival analysis is particularly relevant in redo populations, where early postoperative events largely determine overall prognosis.\u0026sup1;\u0026sup3;,\u0026sup1;⁴\u003c/p\u003e \u003cp\u003eFrom a clinical standpoint, the results support a judicious approach to the patient group that requires a combination of redo cardiac surgery. While the combination of operations cannot always be avoided in a selected group of patients, the risk associated with the combination should always be taken into consideration. In selected high-risk patients, other approaches that are less invasive or staged may also be considered.\u0026sup1;\u0026sup1;,\u0026sup1;\u0026sup2;There were several limitations to the study, including the following: the retrospective single-institution study limits the generalizability of the results, as well as the fact that confounding variables cannot be fully controlled despite adjustment. Another limitation is the fact that the results only measured the short-term outcomes, while long-term survival was not evaluated. However, short-term outcomes were particularly relevant to the setting of redo cardiac surgery, while the consistency of the results across the different analyses supports the validity of the observed associations.\u0026sup1;\u0026sup1;,\u0026sup1;\u0026sup2;\u003c/p\u003e \u003cp\u003eIn conclusion, combined procedures are independently linked to increased early mortality and reduced early survival after redo cardiac surgery. Procedural complexity, cardiopulmonary bypass times, and functional limitations are important predictors of early outcome after combined procedures. Careful patient selection and meticulous planning of combined procedures are essential to optimize outcome in this high-risk population.\u0026sup1;\u0026ndash;\u0026sup3;,⁷\u0026ndash;\u0026sup1;\u0026sup2;\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eSimultaneous surgery has an independent association with increased mortality and decreased survival in the early period following redo surgery. The complexity of the surgery, the cardiopulmonary bypass times, and the functional limitations are major factors that contribute to the risk in the perioperative period. These factors are critical and need to be taken into consideration in the perioperative period.\u003c/p\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eThere are some limitations in this study. For one, the design of the study being retrospective in nature limits the external validity of the data presented in this paper. Second, the focus of the data was only on early in-hospital complications, while long-term survival was not measured in this paper. Third, the perioperative care strategy used in the management of patients with AMI has changed over the long period of the study, which could have affected the early outcome of the patients in this series.\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003eThe authors declare that no external funding was received for this study.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eConflict of Interest:\u0026nbsp;\u003c/em\u003eThe authors declare no conflicts of interest related to this work.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eData Availability:\u0026nbsp;\u003c/em\u003eThe data that support the findings of this study are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eData Availability Statement\u003c/em\u003e\u003cem\u003e:\u0026nbsp;\u003c/em\u003eAll data supporting the findings of this study are available without restriction. The data are stored in the university hospital patient database and can be provided by the corresponding authors upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eDeclaration of Conflicting Interests\u003c/em\u003e\u003cem\u003e:\u0026nbsp;\u003c/em\u003eThe authors declare that there are no conflicts of interest related to the authorship or publication of this study.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eFunding\u003c/em\u003e\u003cem\u003e:\u0026nbsp;\u003c/em\u003eThis research received no specific grant or financial support for the conduct of the study or the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cem\u003eEthics Committee Approval\u003c/em\u003e\u003cem\u003e:\u0026nbsp;\u003c/em\u003eThe study was approved by the Institutional Medical Ethics Committee and conducted in accordance with the principles of the Declaration of Helsinki (Approval No: E-60116787-020-622743).\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eAll authors contributed to the study conception and design. Material preparation, data collection, and analysis were performed by the authors. The first draft of the manuscript was written by the authors, and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLaPar DJ, Ailawadi G, Isbell JM, et al. Outcomes of reoperative cardiac surgery in the modern era. Ann Thorac Surg. 2012;94(2):458\u0026ndash;64.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRoselli EE, Pettersson GB, Blackstone EH. Reoperative cardiac surgery: challenges and outcomes. J Thorac Cardiovasc Surg. 2010;140(3):598\u0026ndash;603.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJones JM, O\u0026rsquo;Kane H, Gladstone DJ, et al. Repeat heart valve surgery: risk factors for operative mortality. Heart. 2001;85(6):633\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFukui T, Takanashi S, Hosoda Y. Impact of combined valve and coronary procedures on operative mortality. Eur J Cardiothorac Surg. 2013;44(6):e296\u0026ndash;302.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGammie JS, Sheng S, Griffith BP, et al. Trends in mitral valve surgery in the United States: outcomes of isolated versus combined procedures. Circulation. 2009;120(11 Suppl):S124\u0026ndash;30.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJamieson WR, Burr LH, Miyagishima RT, et al. Reoperation for cardiac valvular disease: risk assessment. J Thorac Cardiovasc Surg. 2003;126(3):681\u0026ndash;90.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRanucci M, Castelvecchio S, Menicanti L, et al. Cardiopulmonary bypass duration and postoperative mortality. J Thorac Cardiovasc Surg. 2012;144(4):875\u0026ndash;81.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAl-Sarraf N, Thalib L, Hughes A, et al. Cross-clamp time and postoperative outcomes in cardiac surgery. Eur J Cardiothorac Surg. 2011;39(1):e24\u0026ndash;30.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNashef SA, Roques F, Sharples LD, et al. EuroSCORE II. Eur J Cardiothorac Surg. 2012;41(4):734\u0026ndash;44.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShahian DM, O\u0026rsquo;Brien SM, Filardo G, et al. The Society of Thoracic Surgeons 2008 cardiac surgery risk models. Ann Thorac Surg. 2009;88(1 Suppl):S2\u0026ndash;22.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFilsoufi F, Rahmanian PB, Castillo JG, et al. Early outcomes of reoperative cardiac surgery. Ann Thorac Surg. 2006;82(3):803\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBenedetto U, Melina G, Angeloni E, et al. Predictors of early mortality after redo cardiac surgery. J Thorac Cardiovasc Surg. 2014;148(5):2206\u0026ndash;12.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAltman DG, Bland JM. Time to event analyses: survival analysis. BMJ. 1998;317:468\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBradburn MJ, Clark TG, Love SB, et al. Survival analysis methods in medical research. Br J Cancer. 2003;89(2):232\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-cardiovascular-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcar","sideBox":"Learn more about [BMC Cardiovascular Disorders](http://bmccardiovascdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcar/default.aspx","title":"BMC Cardiovascular Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Redo cardiac surgery, Combined procedures, Early outcomes, In-hospital mortality, Kaplan–Meier survival","lastPublishedDoi":"10.21203/rs.3.rs-9076756/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9076756/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eRedo cardiac surgery is being performed more frequently as survival after initial cardiac operations continues to improve. However, repeat procedures remain technically demanding and carry higher perioperative risk, particularly when additional combined interventions are required.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods: \u003c/strong\u003eWe conducted a retrospective observational study including 114 patients who underwent redo cardiac surgery between January 2010 and December 2023. Patients were divided into isolated redo procedures (n=68) and combined redo procedures (n=46). The primary outcome was in-hospital mortality, and early survival was assessed using the Kaplan–Meier method.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003eCompared with isolated redo surgery, combined redo procedures were associated with longer cardiopulmonary bypass and aortic cross-clamp times, increased postoperative drainage, longer ventilation duration, and a longer hospital stay. In-hospital mortality was significantly higher in the combined group (32.6% vs. 13.2%). On multivariable analysis, combined redo surgery remained an independent predictor of in-hospital mortality (OR 3.1, 95% CI 1.4–6.9; p=0.004). Mortality was also associated with cardiopulmonary bypass time ≥180 minutes (OR 2.4, 95% CI 1.1–5.3; p=0.021) and poorer functional status (NYHA class III–IV) (OR 2.0, 95% CI 1.0–4.1; p=0.048). Kaplan–Meier analysis demonstrated reduced early survival after combined redo surgery.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions: \u003c/strong\u003eCombined procedures during redo cardiac surgery are associated with higher early mortality and lower early survival, underscoring the importance of careful patient selection and preoperative risk stratification.\u003c/p\u003e","manuscriptTitle":"Early Outcomes and Predictors of In-Hospital Mortality After Redo Cardiac Surgery: Impact of Combined Procedures","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-15 10:12:04","doi":"10.21203/rs.3.rs-9076756/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-04-29T22:37:24+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-25T13:36:53+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-23T15:53:43+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-22T09:59:01+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-21T21:22:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-19T01:23:21+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"251848379882480608853201883814220821301","date":"2026-04-15T13:22:02+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-04-15T11:32:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"182701354381676437823160398265844159260","date":"2026-04-14T14:04:57+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"41072086373072746755957043610031115427","date":"2026-04-14T13:47:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"275363710275233306362550962962513809999","date":"2026-04-14T13:18:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"29665230460635874769780278358621177769","date":"2026-04-14T12:35:59+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"210612953422309856149707514422656480772","date":"2026-04-12T12:50:04+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"307279721406589051890615476321300394990","date":"2026-04-08T05:54:10+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"42098007361068029197683781633840402678","date":"2026-04-07T20:00:00+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-07T12:28:49+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-03-18T16:59:01+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-03-16T10:16:16+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-03-16T10:15:51+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Cardiovascular Disorders","date":"2026-03-09T20:31:45+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-cardiovascular-disorders","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcar","sideBox":"Learn more about [BMC Cardiovascular Disorders](http://bmccardiovascdisord.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcar/default.aspx","title":"BMC Cardiovascular Disorders","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"492a602c-18bf-466c-9ae7-5d954bd664d3","owner":[],"postedDate":"April 15th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-04-29T22:37:24+00:00","index":71,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-15T10:12:11+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-15 10:12:04","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9076756","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9076756","identity":"rs-9076756","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}