Bilateral Partial Anomalous Pulmonary Venous Return with Intact Interatrial Septum: A Case Report and Review of Literature

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Abdelaziz, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7729632/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 02 Dec, 2025 Read the published version in SN Comprehensive Clinical Medicine → Version 1 posted 18 You are reading this latest preprint version Abstract Introduction: Partial anomalous pulmonary venous return (PAPVR) is a rare congenital anomaly that results in a left-to-right shunt. Bilateral PAPVR is extremely rare and is usually accompanied by an atrial septal defect (ASD). Case presentation: We present a rare case of bilateral PAPVR without ASD. A 56-year-old male patient presented to the cardiology department with atypical chest pain and congested neck veins. The patient underwent echocardiography, which revealed dilated right-sided cardiac chambers and a significant left-to-right shunt. There were no signs of intracardiac shunting by echocardiography as both atrial and ventricular septa were intact. An extra-cardiac left-to-right shunt was suspected, and the patient underwent an electrocardiogram (ECG)-gated cardiac computed tomography (CT), which revealed bilateral PAPVR. In this article, we highlight the role of ECG-gated CT in detecting complex congenital heart diseases, particularly when extra-cardiac blood shunting is suspected. Conclusions: Although it is a rare cause of left-to-right shunt in the elderly, PAPVR should be considered, particularly when there is no evidence of an intracardiac shunt. It is important to note that PAPVR can occur without showing signs of pulmonary hypertension. ECG-gated CT is the preferred imaging modality when suspecting complex congenital cardiac anomalies due to its excellent spatial resolution. Anomalous Pulmonary Venous Return Echocardiography Computed Tomography Congenital Heart Disease Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Background Partial anomalous pulmonary venous return is a rare congenital left-to-right shunt which results from abnormal drainage of one or more of the pulmonary veins to the systemic veins (usually the superior vena cava [SVC]) or directly into the right atrium (RA). The prevalence of PAPVR in autopsy is estimated to be 0.4% to 0.7%. PAPVR may be isolated or associated with ASD, particularly sinus venosus defects ( 1 ) . Unlike total anomalous pulmonary venous return (TAPVR), which is usually diagnosed since birth, PAPVR may be undiscovered until adult life. The left-to-right shunt resulting from the PAPVR can result in pulmonary vascular remodelling and, consequently, PAH. The patient may develop shunt reversal (Eisenmenger’s syndrome) in the presence of an ASD as a result of increased right-sided pressure ( 2 ) . The main differences between TAPVR and PAPVR are summarized in Table 1 ( 3 ) . Transthoracic echocardiography (TTE) has a low sensitivity for the detection of mixed varieties of anomalous pulmonary venous return ( 4 ) . Transesophageal echocardiography is more accurate than conventional TEE; however, certain variants, such as left-sided PAPVR into the innominate vein, may be difficult to detect. ECG-gated cardiac CT allows a superior delineation of pulmonary veins and their drainage patterns. It provides an accurate detection of the anomalous vein and its spatial relationship with the cardiac structures (5) . Cardiac magnetic resonance (CMR) is a reliable method for anatomic evaluation of PAPVR, quantification of the right ventricular (RV) function & volume and quantification of shunt fraction ( 1 ) . An isolated single anomalous pulmonary vein is usually considered hemodynamically insignificant. However, an isolated PAPVR may cause significant shunting if the pulmonary to systemic flow ratio (QP/QS) ≥ 1.5, even in the presence of a single anomalous vein ( 1 ) . In asymptomatic patients with no significantly increased pulmonary blood flow and no signs of RV dysfunction, conservative treatment is recommended. In case of a significant left-to-right shunt [QP/QS ≥ 1.5], RV enlargement and development of symptoms, surgical management is indicated. In patients undergoing surgical repair, the 2018 adult congenital heart disease (ACHD) guidelines recommend the systolic pulmonary artery (PA) pressure to be < 50% of the systemic pressure and pulmonary vascular resistance (PVR) to be < 1/3 of the systemic vascular resistance ( 2 ) . This manuscript presents a challenging case of an adult patient with an atypical presentation of PAPVR. The echocardiographic findings indicated a significant left-to-right shunt (QP/QS = 3.2) and showed dilated right-sided cardiac chambers. This raised suspicion of an extracardiac shunt, especially since the interatrial septum (IAS) was intact, a finding confirmed by ECG-gated CT. Notably, this case involved bilateral PAPVR, which is uncommon, as PAPVR typically presents as right-sided with an ASD. We also emphasize the importance of cardiac CT as a valuable complementary tool to traditional cardiology investigations, such as echocardiography and catheter angiography. Case presentation History and clinical presentation: A male patient, 56 years old, came to the cardiology outpatient clinic complaining of atypical chest pain and recurrent palpitation for 7 months. The patient had no relevant past medical history. He was not diabetic or hypertensive. General and cardiac examination The general examination revealed congested, pulsating neck veins, a normal liver span, and no lower limb oedema. Oxygen saturation was maintained at 96% in the supine, sitting, and erect positions, with no other remarkable signs. Local cardiac examination revealed a diffuse apical impulse in the left fifth intercostal space in the anterior axillary line. ECG findings A 12-lead ECG was done and revealed a sinus rhythm (75 BPM), incomplete right bundle branch block, normal PR and QTc intervals. Imaging findings : 1. Echocardiogram Echocardiography revealed a dilated RV [Fig. 1 ] (RV basal, mid and longitudinal diameters were 5.2,4.7, and 9 cm in order) and RA (RA area was 27 cm), as well as signs of volume overload on the right side. QP: QS was calculated and found to be 3.2 [Fig. 1 ]. RV fractional area change (FAC) was 45% and tricuspid annular plane systolic excursion (TAPSE) was 22 mm. There were no signs of pulmonary hypertension, Pulmonary arterial systolic pressure (PASP) 35 mmHg calculated from the TR (tricuspid regurge) signal. Normal morphology of the tricuspid and pulmonary valves was also observed. The IAS was intact [Fig. 1 ] and stretched with a normal coronary sinus diameter and intact roof with diastolic septal flattening of the interventricular septum (IVS). There were no signs of patent ductus arteriosus (PDA). Injection of a 10 ml bolus of agitated saline in the left antecubital vein with and without Valsalva manoeuvre and bimanual hepatic compression revealed non-opacification of the left side chambers after 12 cycles [Fig. 2 ], excluding intracardiac shunts and the possibility of arteriovenous malformations. Subcostal bicaval and suprasternal views revealed dilated SVC with exaggerated flow. The remaining possibility was pulmonary to systemic venovenous shunt. The patient was referred to ECG-gated CT for more anatomical delineation. 2. ECG-gated cardiac CT : Equipment The patient underwent ECG-gated cardiac CT on a multidetector CT scan (GE Healthcare). 150 ml of (350 mg/ml) of iohexol contrast media was injected through the automatic injector. Findings The right-sided cardiac chambers were enlarged, and the IAS was intact [Fig. 3 ]. Abnormal drainage of the right superior & middle pulmonary veins (RSPV&RMPV) into the SVC was identified [Figs. 4 & 5 ]. Anomalous drainage of the left superior pulmonary vein (LSPV) into the innominate vein was also seen [Figs. 4 & 5 ]. Based on the previously mentioned findings. The patient was diagnosed with bilateral PAPVR with intact ASD. There was also a significant narrowing in the mid-segment of the left anterior descending (LAD) coronary artery [Fig. 6 ]. Discussion During embryogenesis, the left atrium and the pulmonary veins develop independently. The lung buds emerge from the foregut and drain into a vascular network through the cardinal and umbilicovitelline veins, which are part of the systemic circulation. The primitive atrium then connects to the pulmonary vascular bed. Over time, the links between the pulmonary vascular bed and the systemic venous system regress. Failure of this regression leads to PAPVR or TAPVR ( 6 ) . The age of presentation of PAPVR is variable according to the degree of left-to-right shunt. El-Kersh et al. presented various cases in their case series, some of which were middle-aged, while others were of a young age ( 2 ) . Ebrahimi et al. also presented a patient aged 58 years with a late presentation of PAPVR ( 7 ) . In our case, the patient was 56 years old, agreeing with both of the previously mentioned. It is inferred from the previous that PAPVR should be suspected at any age in the presence of a significant left-to-right shunt. Partial anomalous pulmonary venous return has a diverse symptomatology. Our patient presented with atypical chest pain and had no past medical history. In the case presented by Ebrahimi et al., the patient presented with progressive dyspnea that continued over two years ( 7 ) . The patient in the latter had a history of uncontrolled hypertension, unlike our patient, who had no relevant medical history. The patient, aged 66 years, who was presented in the case series of El-Kersh et al. and belonged to the same age of our patient, also suffered from exertional dyspnea ( 2 ) . Patel et al. presented a patient with morbid obesity, in whom PAPVR was discovered during pre-operative cardiac risk stratification before gastric bypass surgery ( 8 ) . The patient also suffered from dyspnea in the latter, yet the patient was morbidly obese and was 33 years old. The dyspnea sustained by the patient might have been related to the morbid obesity, not the right-to-left shunt. The other younger patients presented in the case series of El-Kersh et al. suffered from signs of PAH ( 2 ) . From the previous, we can conclude that PAPVR may be presented at a young age due to significant shunting of blood to the pulmonary circulation. The PAPVR can also present at an elderly age, coupled with other comorbidities such as right-sided heart failure due to chronic volume overload, as in the case of our patient. In their study, which was focused on PAPVR, Rahnama et al. mentioned an insignificant number of patients with ischemic heart disease [p-value = 0.99] ( 9 ) . In our case, significant LAD narrowing was concomitantly discovered with the PAPVR [Fig. 6 ]. From the previous, we can conclude that the superadded ischemic burden of the myocardium may unmask the occult PAPVR. The establishment of a probable association between significant coronary artery disease and PAPVR presentation in adult age needs to be emphasized in future dedicated studies. The incidence of left-sided PAPVR is estimated to be only 10% of the cases with anomalous drainage, with the anomalous drainage of the left superior lobe pulmonary vein (LSPV) being even rarer, accounting for only 3% (10) . In their study, Rahnama et al. mentioned zero incidence of bilateral anomalous pulmonary venous drainage ( 9 ) . The latter also mentioned that among the other types of anomalous pulmonary venous drainage, the anomalous drainage of the right superior pulmonary vein (RSPV) is the most prevalent (76%). In the case series of El-Kersh et al., no cases were mentioned with bilateral PAPVR ( 2 ) . Lei and Zhou presented a case of bilateral PAPVR with the RSPV and right middle pulmonary vein (RMPV) draining into the SVC and the LSPV draining into the innominate vein ( 5 ) , which was exactly the same in our case [Figs. 4 & 5 ]. However, their patient had an ASD, contradicting ours, which lacked ASD [Figs. 1 & 3 ]. Another difference is the age of presentation. As in our case, the patient presented late (at 56 years old) despite the significant left-to-right shunt (QP/QS = 3.2), while in their case, the patient was 13 years old. We can infer that the presentation of PAPVR may be delayed even in the presence of significant shunting of blood to the pulmonary circulation. According to Alsoufi et al, there is a frequent association between PAPVR and ASD, especially sinus venosus (in 80% of the cases) ( 11 ) . This association was also confirmed by the study conducted by Rahnama et al. The latter also found that the QP/QS ratio was significantly higher in the group of patients with ASD than in those without ASD ( 9 ) . In our case, the patient was found to have a markedly elevated QP/QS ratio (3.2) [Fig. 1 ], despite the absence of an ASD [Figs. 1 & 3 ]. It is concluded from the previous that the significant left-to-right shunt in PAPVR is contributed solely by the anomalous drainage, which may contribute independently to the volume and pressure overload on the RV. The patient in our case had no signs of PAH by TTE; however, there were signs of RV volume and pressure overload. Rahnama et al. mentioned that the QP/QS ratio is the most important factor determining the presence of PAH ( 9 ) . Despite the significant left-to-right shunt in our case, there were no signs of PAH. We can conclude that although PAH is the most dreaded complication of chronic pulmonary shunting due to endothelial dysfunction and the subsequent vasoconstriction, there may be certain cases exhibiting a high QP/QS ratio with long-term tolerance of RV overload, which may be compensated by the RV remodelling in response to chronic altered hemodynamics. In our study, a significant left-to-right shunt was suspected, and the diagnosis of PAPVR was established by ECG-gated cardiac CT [Figs. 4 & 5 ]. We didn’t need to perform CMR as the QP/QS was already calculated in advance [Fig. 1 ]. In all the previously mentioned case reports, cardiac CT was performed ( 2 , 5 , 7 , 8 ) . From this, we can conclude that ECG-gated cardiac CT is a valuable investigation that should be used for accurate delineation of complex cardiac anomalies, complementary to the other conventional imaging modalities. We encountered several challenges in diagnosing our case. First, the patient presented at an atypical age, as most individuals with bilateral PAPVR are diagnosed early in life. Second, despite the significant left-to-right shunt, the patient showed no signs of PAH, while most adults with chronic PAPVR typically exhibit PAH symptoms. Lastly, the presence of an intact IAS [Figs. 1 & 3 ] was extremely rare, particularly in a case of bilateral PAPVR. Conclusions Despite its rarity, PAPVR should be considered in any case with unexplained signs of left-to-right shunt, particularly in the absence of intracardiac shunting. Although the PAPVR and the ASD are frequently associated, there may be some cases with absent ASD. Bilateral PAPVR is an extremely rare, complex cardiac anomaly that needs a high index of suspicion and a diagnosis to consider, especially in the case of atypical age of presentation. A significant left-to-right shunt may occur without signs of PAH. The ECG-gated cardiac CT is the primary modality for diagnosing complex congenital heart disease, including PAPVR. Abbreviations PAPVR: Partial anomalous pulmonary venous return ASD: Atrial septal defect PAH: Pulmonary arterial hypertension ECG: Electrocardiogram CT: Computed tomography SVC: Superior vena cava RA: Right atrium TAPVR: Total anomalous pulmonary venous return TTE: Transthoracic echocardiography CMR: Cardiac magnetic resonance RV: Right ventricle QP/QS: Pulmonary to systemic flow ratio ACHD: Adult congenital heart disease PVR: Pulmonary vascular resistance IAS: Interatrial septum BPM: Beat per minute TAPSE: Tricuspid annular plane systolic excursion PASP: Pulmonary arterial systolic pressure TR: Tricuspid regurge IVS: Interventricular septum RSPV: Right superior pulmonary vein RMPV: right middle pulmonary vein LSPV: Left superior pulmonary vein LAD: Left anterior descending MIP: Maximum intensity projection VR: Volume rendering MPR: Multiplanar reformat Declarations Ethics approval and consent to participate: Not applicable. Consent for publication: Though the patient’s anonymity was preserved, informed consent was obtained from the patients (consent model is available on reasonable request). Availability of data and materials: The datasets are available from the corresponding author on reasonable request. Competing interests: The authors declare that they have no competing interests. Funding: The authors declare that they have no funding sources. Code availability: The authors declare that all data, materials, and software applications support their published claims and comply with field standards. Authors' contributions: MSA: Analysed the patient’s data, wrote the manuscript, interpreted the imaging findings and prepared the figures. DF: Interpreted the imaging findings and reviewed the manuscript. AA: Reviewed the manuscript and contributed to the background section. AAB: Reviewed the manuscript and contributed to the discussion section. AM: Reviewed the manuscript and contributed to the discussion section. SM: Reviewed the manuscript and contributed to the discussion section. NM: Reviewed the manuscript and contributed to the background section. FM: Reviewed the manuscript and contributed to the background section. AE: Reviewed the manuscript and contributed to the discussion section. KS: Reviewed the manuscript, performed the echocardiography and wrote the case presentation section. Acknowledgements: Not applicable References Hatipoglu S, Almogheer B, Mahon C, Houshmand G, Uygur B, Giblin GT, Krupickova S, Baksi AJ, Alpendurada F, Prasad SK, Babu-Narayan SV. Clinical significance of partial anomalous pulmonary venous connections (isolated and atrial septal defect associated) determined by cardiovascular magnetic resonance. Circulation: Cardiovascular Imaging. 2021 Aug;14(8):e012371. El-Kersh K, Homsy E, Daniels CJ, Smith JS. Partial anomalous pulmonary venous return: a case series with management approach. Respiratory medicine case reports. 2019 Jan 1;27:100833. Abbara S, Kligerman S. Diagnostic Imaging: Cardiovascular-E-Book. Elsevier Health Sciences; 2025 May 6. Ali F, Qureshi S, Amanullah M, Atiq M. Accuracy of echocardiography in diagnosing total anomalous pulmonary venous return. Pakistan Journal of Medical Sciences. 2018 Sep;34(5):1094. Lei L, Zhou Y. Bilateral Partial Anomalous Pulmonary Venous Return. Radiology. 2025 Jun 10;315(3):e242606. Latson LA, Prieto LR. Congenital and acquired pulmonary vein stenosis. Circulation. 2007 Jan 2;115(1):103-8. Ebrahimi P, Mandegar MH, Jafari Fesharaki M, Ghasemloo N, Ramezani P, Akbari T, Naderi F. Unusual presentation of a patient with partial anomalous pulmonary venous connections without a septal defect: a case report and literature review. International Journal of Emergency Medicine. 2025 Jan 7;18(1):6. Patel HR, Bhutani S, Shamoon F, Virk H. Deciphering a case of pulmonary hypertension in a young female: Partial anomalous pulmonary venous drainage the culprit. Annals of Thoracic Medicine. 2018 Jan 1;13(1):55-8. Rahnama N, Kubangumusu L, Pasquet A, Robert A, Pouleur AC, Carbonez K, Kefer J, Moniotte S, Poncelet A, de Becco G, Ghaye B. Partial anomalous pulmonary venous return in adults: Insight into pulmonary hypertension. International Journal of Cardiology Congenital Heart Disease. 2023 Mar 1;11:100426. Nath R, Murphy W, Aronson B. Rare case of left upper lobe partial anomalous pulmonary venous connection. Journal of Radiology Case Reports. 2013 Jun 1;7(6):9. Alsoufi B, Cai S, Van Arsdell GS, Williams WG, Caldarone CA, Coles JG. Outcomes after surgical treatment of children with partial anomalous pulmonary venous connection. The Annals of thoracic surgery. 2007 Dec 1;84(6):2020-6. Table 1 Table [1]: Comparison between total and partial anomalous pulmonary venous return PAPVR TAPVR Presentation Later in adult life Since birth Pathophysiology and hemodynamics Anomalous connection of one or more of the pulmonary veins (more on the right side) to the systemic veins or the right atrium. Anomalous connection of all pulmonary veins directly to the systemic veins or the right atrium. Classification and sub-categories Classified according to the number of anomalous veins and bilaterality into: PAPVR of the right pulmonary veins to the right atrium associated with secondum ASD. PAPVR of the right pulmonary veins to the SVC or IVC with sinus venosus ASD. PAPVR of the right pulmonary veins to the IVC with scimitar syndrome (Hypoplastic right lung and congenital venolobar syndrome). Mixed drainage to multiple sites with more than one anomalous pulmonary vein. Classified according to the site of insertion of pulmonary veins: Supracardiac (the most common): Left innominate vein, SVC and Azygous vein. Cardiac: Right atrium and Coronary sinus. Infracardiac: IVC. Portal vein or left gastric vein. Mixed pattern. Association Horseshoe lung. Anomalies of the right hemidiaphragm. Anomalies of the bony thorax and soft tissues. Visceral heterotaxy (right-sided isomerism) PAPVR: partial anomalous pulmonary venous return TAPVR: total anomalous pulmonary venous return SVC: superior vena cava IVC: inferior vena cava ASD: atrial septal defect Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 02 Dec, 2025 Read the published version in SN Comprehensive Clinical Medicine → Version 1 posted Editorial decision: Revision requested 22 Oct, 2025 Reviews received at journal 22 Oct, 2025 Reviews received at journal 19 Oct, 2025 Reviews received at journal 15 Oct, 2025 Reviewers agreed at journal 14 Oct, 2025 Reviewers agreed at journal 14 Oct, 2025 Reviewers agreed at journal 11 Oct, 2025 Reviewers agreed at journal 11 Oct, 2025 Reviews received at journal 11 Oct, 2025 Reviews received at journal 10 Oct, 2025 Reviewers agreed at journal 10 Oct, 2025 Reviewers agreed at journal 09 Oct, 2025 Reviewers agreed at journal 09 Oct, 2025 Reviewers agreed at journal 09 Oct, 2025 Reviewers invited by journal 09 Oct, 2025 Editor assigned by journal 06 Oct, 2025 Submission checks completed at journal 05 Oct, 2025 First submitted to journal 27 Sep, 2025 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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02:45:39","extension":"html","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":68239,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-7729632/v1/410460e4266b96b5ae0f0913.html"},{"id":94155319,"identity":"43096fda-bc21-457a-b01d-c24d052c578e","added_by":"auto","created_at":"2025-10-23 02:45:39","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":1143166,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u0026nbsp;\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-7729632/v1/964786a91aa1b2a06d8d6cc8.png"},{"id":94155328,"identity":"0db6f15b-9dad-417d-8e3c-6bd5dc192003","added_by":"auto","created_at":"2025-10-23 02:45:39","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":759504,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u0026nbsp;\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-7729632/v1/c0a1575318eef730b0f59474.png"},{"id":94155321,"identity":"232bd3aa-1878-4c36-82e8-4bca2ef560fa","added_by":"auto","created_at":"2025-10-23 02:45:39","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":611788,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u0026nbsp;\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-7729632/v1/51df8b7a166df1d2a2c71167.png"},{"id":94155323,"identity":"efbe7d93-2ffe-4029-b8fa-80de2df1a490","added_by":"auto","created_at":"2025-10-23 02:45:39","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1714522,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u0026nbsp;\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-7729632/v1/3a547fe50fcdffe0959c6932.png"},{"id":94156634,"identity":"ed3aaff6-2f90-4c69-afc3-4c221eb27cae","added_by":"auto","created_at":"2025-10-23 02:53:39","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":1433808,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u0026nbsp;\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-7729632/v1/735eb3e37f96621c01a95dd6.png"},{"id":94155337,"identity":"a3eb5a62-f4e7-40c6-898f-720955dd3f59","added_by":"auto","created_at":"2025-10-23 02:45:39","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":807959,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend\u0026nbsp;\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-7729632/v1/9b08899c39274808226b3511.png"},{"id":97724094,"identity":"641ad667-bbcd-4075-ae02-7097b907f3f7","added_by":"auto","created_at":"2025-12-08 16:11:49","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":11152818,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7729632/v1/fd8bc3e4-9b39-4a43-ba80-892e2b38e660.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Bilateral Partial Anomalous Pulmonary Venous Return with Intact Interatrial Septum: A Case Report and Review of Literature","fulltext":[{"header":"Background","content":"\u003cp\u003ePartial anomalous pulmonary venous return is a rare congenital left-to-right shunt which results from abnormal drainage of one or more of the pulmonary veins to the systemic veins (usually the superior vena cava [SVC]) or directly into the right atrium (RA). The prevalence of PAPVR in autopsy is estimated to be 0.4% to 0.7%. PAPVR may be isolated or associated with ASD, particularly sinus venosus defects \u003csup\u003e(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/sup\u003e. Unlike total anomalous pulmonary venous return (TAPVR), which is usually diagnosed since birth, PAPVR may be undiscovered until adult life. The left-to-right shunt resulting from the PAPVR can result in pulmonary vascular remodelling and, consequently, PAH. The patient may develop shunt reversal (Eisenmenger\u0026rsquo;s syndrome) in the presence of an ASD as a result of increased right-sided pressure \u003csup\u003e(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/sup\u003e. The main differences between TAPVR and PAPVR are summarized in Table\u0026nbsp;1 \u003csup\u003e(\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e)\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eTransthoracic echocardiography (TTE) has a low sensitivity for the detection of mixed varieties of anomalous pulmonary venous return \u003csup\u003e(\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e)\u003c/sup\u003e. Transesophageal echocardiography is more accurate than conventional TEE; however, certain variants, such as left-sided PAPVR into the innominate vein, may be difficult to detect. ECG-gated cardiac CT allows a superior delineation of pulmonary veins and their drainage patterns. It provides an accurate detection of the anomalous vein and its spatial relationship with the cardiac structures \u003csup\u003e(5)\u003c/sup\u003e. Cardiac magnetic resonance (CMR) is a reliable method for anatomic evaluation of PAPVR, quantification of the right ventricular (RV) function \u0026amp; volume and quantification of shunt fraction \u003csup\u003e(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eAn isolated single anomalous pulmonary vein is usually considered hemodynamically insignificant. However, an isolated PAPVR may cause significant shunting if the pulmonary to systemic flow ratio (QP/QS)\u0026thinsp;\u0026ge;\u0026thinsp;1.5, even in the presence of a single anomalous vein \u003csup\u003e(\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e)\u003c/sup\u003e. In asymptomatic patients with no significantly increased pulmonary blood flow and no signs of RV dysfunction, conservative treatment is recommended. In case of a significant left-to-right shunt [QP/QS\u0026thinsp;\u0026ge;\u0026thinsp;1.5], RV enlargement and development of symptoms, surgical management is indicated. In patients undergoing surgical repair, the 2018 adult congenital heart disease (ACHD) guidelines recommend the systolic pulmonary artery (PA) pressure to be \u0026lt;\u0026thinsp;50% of the systemic pressure and pulmonary vascular resistance (PVR) to be \u0026lt;\u0026thinsp;1/3 of the systemic vascular resistance \u003csup\u003e(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThis manuscript presents a challenging case of an adult patient with an atypical presentation of PAPVR. The echocardiographic findings indicated a significant left-to-right shunt (QP/QS\u0026thinsp;=\u0026thinsp;3.2) and showed dilated right-sided cardiac chambers. This raised suspicion of an extracardiac shunt, especially since the interatrial septum (IAS) was intact, a finding confirmed by ECG-gated CT. Notably, this case involved bilateral PAPVR, which is uncommon, as PAPVR typically presents as right-sided with an ASD. We also emphasize the importance of cardiac CT as a valuable complementary tool to traditional cardiology investigations, such as echocardiography and catheter angiography.\u003c/p\u003e"},{"header":"Case presentation","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\n \u003ch2\u003eHistory and clinical presentation:\u003c/h2\u003e\n \u003cp\u003eA male patient, 56 years old, came to the cardiology outpatient clinic complaining of atypical chest pain and recurrent palpitation for 7 months. The patient had no relevant past medical history. He was not diabetic or hypertensive.\u003c/p\u003e\n\u003c/div\u003e\n\u003ch3\u003eGeneral and cardiac examination\u003c/h3\u003e\n\u003cp\u003eThe general examination revealed congested, pulsating neck veins, a normal liver span, and no lower limb oedema. Oxygen saturation was maintained at 96% in the supine, sitting, and erect positions, with no other remarkable signs. Local cardiac examination revealed a diffuse apical impulse in the left fifth intercostal space in the anterior axillary line.\u003c/p\u003e\n\u003ch3\u003eECG findings\u003c/h3\u003e\n\u003cp\u003eA 12-lead ECG was done and revealed a sinus rhythm (75 BPM), incomplete right bundle branch block, normal PR and QTc intervals.\u003c/p\u003e\n\u003cp\u003e\u003cspan type=\"BoldItalicUnderline\" class=\"BoldItalicUnderline\" name=\"Emphasis\"\u003eImaging findings\u003c/span\u003e:\u003c/p\u003e\n\u003ch3\u003e1. Echocardiogram\u003c/h3\u003e\n\u003cp\u003eEchocardiography revealed a dilated RV [Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e] (RV basal, mid and longitudinal diameters were 5.2,4.7, and 9 cm in order) and RA (RA area was 27 cm), as well as signs of volume overload on the right side. QP: QS was calculated and found to be 3.2 [Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e]. RV fractional area change (FAC) was 45% and tricuspid annular plane systolic excursion (TAPSE) was 22 mm. There were no signs of pulmonary hypertension, Pulmonary arterial systolic pressure (PASP) 35 mmHg calculated from the TR (tricuspid regurge) signal. Normal morphology of the tricuspid and pulmonary valves was also observed. The IAS was intact [Fig. \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e] and stretched with a normal coronary sinus diameter and intact roof with diastolic septal flattening of the interventricular septum (IVS). There were no signs of patent ductus arteriosus (PDA). Injection of a 10 ml bolus of agitated saline in the left antecubital vein with and without Valsalva manoeuvre and bimanual hepatic compression revealed non-opacification of the left side chambers after 12 cycles [Fig. \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e], excluding intracardiac shunts and the possibility of arteriovenous malformations. Subcostal bicaval and suprasternal views revealed dilated SVC with exaggerated flow. The remaining possibility was pulmonary to systemic venovenous shunt. The patient was referred to ECG-gated CT for more anatomical delineation.\u003c/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003c/span\u003e\u003c/p\u003e\n\u003cp\u003e\u003cspan type=\"Underline\" class=\"Underline\" name=\"Emphasis\"\u003e2. ECG-gated cardiac CT\u003c/span\u003e:\u003c/p\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEquipment\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe patient underwent ECG-gated cardiac CT on a multidetector CT scan (GE Healthcare). 150 ml of (350 mg/ml) of iohexol contrast media was injected through the automatic injector.\u003c/p\u003e\n\u003ch3\u003eFindings\u003c/h3\u003e\n\u003cp\u003eThe right-sided cardiac chambers were enlarged, and the IAS was intact [Fig. \u003cspan class=\"InternalRef\"\u003e3\u003c/span\u003e]. Abnormal drainage of the right superior \u0026amp; middle pulmonary veins (RSPV\u0026amp;RMPV) into the SVC was identified [Figs. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e \u0026amp; \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e]. Anomalous drainage of the left superior pulmonary vein (LSPV) into the innominate vein was also seen [Figs. \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e \u0026amp; \u003cspan class=\"InternalRef\"\u003e5\u003c/span\u003e]. Based on the previously mentioned findings. The patient was diagnosed with bilateral PAPVR with intact ASD. There was also a significant narrowing in the mid-segment of the left anterior descending (LAD) coronary artery [Fig. \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eDuring embryogenesis, the left atrium and the pulmonary veins develop independently. The lung buds emerge from the foregut and drain into a vascular network through the cardinal and umbilicovitelline veins, which are part of the systemic circulation. The primitive atrium then connects to the pulmonary vascular bed. Over time, the links between the pulmonary vascular bed and the systemic venous system regress. Failure of this regression leads to PAPVR or TAPVR \u003csup\u003e(\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e)\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThe age of presentation of PAPVR is variable according to the degree of left-to-right shunt. El-Kersh et al. presented various cases in their case series, some of which were middle-aged, while others were of a young age \u003csup\u003e(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/sup\u003e. Ebrahimi et al. also presented a patient aged 58 years with a late presentation of PAPVR \u003csup\u003e(\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e)\u003c/sup\u003e. In our case, the patient was 56 years old, agreeing with both of the previously mentioned. It is inferred from the previous that PAPVR should be suspected at any age in the presence of a significant left-to-right shunt.\u003c/p\u003e\u003cp\u003ePartial anomalous pulmonary venous return has a diverse symptomatology. Our patient presented with atypical chest pain and had no past medical history. In the case presented by Ebrahimi et al., the patient presented with progressive dyspnea that continued over two years \u003csup\u003e(\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e)\u003c/sup\u003e. The patient in the latter had a history of uncontrolled hypertension, unlike our patient, who had no relevant medical history. The patient, aged 66 years, who was presented in the case series of El-Kersh et al. and belonged to the same age of our patient, also suffered from exertional dyspnea \u003csup\u003e(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/sup\u003e. Patel et al. presented a patient with morbid obesity, in whom PAPVR was discovered during pre-operative cardiac risk stratification before gastric bypass surgery \u003csup\u003e(\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e)\u003c/sup\u003e. The patient also suffered from dyspnea in the latter, yet the patient was morbidly obese and was 33 years old. The dyspnea sustained by the patient might have been related to the morbid obesity, not the right-to-left shunt. The other younger patients presented in the case series of El-Kersh et al. suffered from signs of PAH \u003csup\u003e(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/sup\u003e. From the previous, we can conclude that PAPVR may be presented at a young age due to significant shunting of blood to the pulmonary circulation. The PAPVR can also present at an elderly age, coupled with other comorbidities such as right-sided heart failure due to chronic volume overload, as in the case of our patient. In their study, which was focused on PAPVR, Rahnama et al. mentioned an insignificant number of patients with ischemic heart disease [p-value\u0026thinsp;=\u0026thinsp;0.99] \u003csup\u003e(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e)\u003c/sup\u003e. In our case, significant LAD narrowing was concomitantly discovered with the PAPVR [Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e]. From the previous, we can conclude that the superadded ischemic burden of the myocardium may unmask the occult PAPVR. The establishment of a probable association between significant coronary artery disease and PAPVR presentation in adult age needs to be emphasized in future dedicated studies.\u003c/p\u003e\u003cp\u003eThe incidence of left-sided PAPVR is estimated to be only 10% of the cases with anomalous drainage, with the anomalous drainage of the left superior lobe pulmonary vein (LSPV) being even rarer, accounting for only 3% \u003csup\u003e(10)\u003c/sup\u003e. In their study, Rahnama et al. mentioned zero incidence of bilateral anomalous pulmonary venous drainage \u003csup\u003e(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e)\u003c/sup\u003e. The latter also mentioned that among the other types of anomalous pulmonary venous drainage, the anomalous drainage of the right superior pulmonary vein (RSPV) is the most prevalent (76%). In the case series of El-Kersh et al., no cases were mentioned with bilateral PAPVR \u003csup\u003e(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e)\u003c/sup\u003e. Lei and Zhou presented a case of bilateral PAPVR with the RSPV and right middle pulmonary vein (RMPV) draining into the SVC and the LSPV draining into the innominate vein \u003csup\u003e(\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e)\u003c/sup\u003e, which was exactly the same in our case [Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e \u0026amp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e]. However, their patient had an ASD, contradicting ours, which lacked ASD [Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u0026amp; \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e]. Another difference is the age of presentation. As in our case, the patient presented late (at 56 years old) despite the significant left-to-right shunt (QP/QS\u0026thinsp;=\u0026thinsp;3.2), while in their case, the patient was 13 years old. We can infer that the presentation of PAPVR may be delayed even in the presence of significant shunting of blood to the pulmonary circulation.\u003c/p\u003e\u003cp\u003eAccording to Alsoufi et al, there is a frequent association between PAPVR and ASD, especially sinus venosus (in 80% of the cases) \u003csup\u003e(\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e)\u003c/sup\u003e. This association was also confirmed by the study conducted by Rahnama et al. The latter also found that the QP/QS ratio was significantly higher in the group of patients with ASD than in those without ASD \u003csup\u003e(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e)\u003c/sup\u003e. In our case, the patient was found to have a markedly elevated QP/QS ratio (3.2) [Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e], despite the absence of an ASD [Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u0026amp; \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e]. It is concluded from the previous that the significant left-to-right shunt in PAPVR is contributed solely by the anomalous drainage, which may contribute independently to the volume and pressure overload on the RV.\u003c/p\u003e\u003cp\u003eThe patient in our case had no signs of PAH by TTE; however, there were signs of RV volume and pressure overload. Rahnama et al. mentioned that the QP/QS ratio is the most important factor determining the presence of PAH \u003csup\u003e(\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e)\u003c/sup\u003e. Despite the significant left-to-right shunt in our case, there were no signs of PAH. We can conclude that although PAH is the most dreaded complication of chronic pulmonary shunting due to endothelial dysfunction and the subsequent vasoconstriction, there may be certain cases exhibiting a high QP/QS ratio with long-term tolerance of RV overload, which may be compensated by the RV remodelling in response to chronic altered hemodynamics.\u003c/p\u003e\u003cp\u003eIn our study, a significant left-to-right shunt was suspected, and the diagnosis of PAPVR was established by ECG-gated cardiac CT [Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e \u0026amp; \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e]. We didn\u0026rsquo;t need to perform CMR as the QP/QS was already calculated in advance [Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e]. In all the previously mentioned case reports, cardiac CT was performed \u003csup\u003e(\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e)\u003c/sup\u003e. From this, we can conclude that ECG-gated cardiac CT is a valuable investigation that should be used for accurate delineation of complex cardiac anomalies, complementary to the other conventional imaging modalities.\u003c/p\u003e\u003cp\u003eWe encountered several challenges in diagnosing our case. First, the patient presented at an atypical age, as most individuals with bilateral PAPVR are diagnosed early in life. Second, despite the significant left-to-right shunt, the patient showed no signs of PAH, while most adults with chronic PAPVR typically exhibit PAH symptoms. Lastly, the presence of an intact IAS [Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e \u0026amp; \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e] was extremely rare, particularly in a case of bilateral PAPVR.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eDespite its rarity, PAPVR should be considered in any case with unexplained signs of left-to-right shunt, particularly in the absence of intracardiac shunting. Although the PAPVR and the ASD are frequently associated, there may be some cases with absent ASD. Bilateral PAPVR is an extremely rare, complex cardiac anomaly that needs a high index of suspicion and a diagnosis to consider, especially in the case of atypical age of presentation. A significant left-to-right shunt may occur without signs of PAH. The ECG-gated cardiac CT is the primary modality for diagnosing complex congenital heart disease, including PAPVR.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cul\u003e\n \u003cli\u003ePAPVR: Partial anomalous pulmonary venous return\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eASD: Atrial septal defect\u003c/li\u003e\n \u003cli\u003ePAH: Pulmonary arterial hypertension\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eECG: Electrocardiogram\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eCT: Computed tomography\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eSVC: Superior vena cava\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eRA: Right atrium\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eTAPVR: Total anomalous pulmonary venous return\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eTTE: Transthoracic echocardiography\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eCMR: Cardiac magnetic resonance\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eRV: Right ventricle\u003c/li\u003e\n \u003cli\u003eQP/QS: Pulmonary to systemic flow ratio\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eACHD: Adult congenital heart disease\u0026nbsp;\u003c/li\u003e\n \u003cli\u003ePVR: Pulmonary vascular resistance\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eIAS: Interatrial septum\u003c/li\u003e\n \u003cli\u003eBPM: Beat per minute\u003c/li\u003e\n \u003cli\u003eTAPSE: Tricuspid annular plane systolic excursion\u0026nbsp;\u003c/li\u003e\n \u003cli\u003ePASP: Pulmonary arterial systolic pressure\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eTR: Tricuspid regurge\u003c/li\u003e\n \u003cli\u003eIVS: Interventricular septum\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eRSPV: Right superior pulmonary vein\u003c/li\u003e\n \u003cli\u003eRMPV: right middle pulmonary vein\u003c/li\u003e\n \u003cli\u003eLSPV: Left superior pulmonary vein\u003c/li\u003e\n \u003cli\u003eLAD: Left anterior descending\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eMIP: Maximum intensity projection\u003c/li\u003e\n \u003cli\u003eVR: Volume rendering\u003c/li\u003e\n \u003cli\u003eMPR: Multiplanar reformat\u0026nbsp;\u003c/li\u003e\n\u003c/ul\u003e\n"},{"header":"Declarations","content":"\u003cul\u003e\n \u003cli\u003e\u003cstrong\u003eEthics approval and consent to participate:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eConsent for publication:\u0026nbsp;\u003c/strong\u003eThough the patient\u0026rsquo;s anonymity was preserved, informed consent was obtained from the patients (consent model is available on reasonable request).\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eAvailability of data and materials:\u0026nbsp;\u003c/strong\u003eThe datasets are available from the corresponding author on reasonable request.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eCompeting interests:\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no competing interests.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no funding sources.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eCode availability:\u0026nbsp;\u003c/strong\u003eThe authors declare that all data, materials, and software applications support their published claims and comply with field standards.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eAuthors\u0026apos; contributions:\u003c/strong\u003e\n \u003col\u003e\n \u003cli\u003eMSA: Analysed the patient\u0026rsquo;s data, wrote the manuscript, interpreted the imaging findings and prepared the figures.\u003c/li\u003e\n \u003cli\u003eDF: Interpreted the imaging findings and reviewed the manuscript.\u003c/li\u003e\n \u003cli\u003eAA: Reviewed the manuscript and contributed to the background section.\u003c/li\u003e\n \u003cli\u003eAAB: Reviewed the manuscript and contributed to the discussion section.\u003c/li\u003e\n \u003cli\u003eAM: Reviewed the manuscript and contributed to the discussion section.\u003c/li\u003e\n \u003cli\u003eSM: Reviewed the manuscript and contributed to the discussion section.\u003c/li\u003e\n \u003cli\u003eNM: Reviewed the manuscript and contributed to the background section.\u003c/li\u003e\n \u003cli\u003eFM: Reviewed the manuscript and contributed to the background section.\u003c/li\u003e\n \u003cli\u003eAE: Reviewed the manuscript and contributed to the discussion section.\u003c/li\u003e\n \u003cli\u003eKS: Reviewed the manuscript, performed the echocardiography and wrote the case presentation section.\u003c/li\u003e\n \u003c/ol\u003e\n \u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eAcknowledgements: Not applicable\u003c/strong\u003e\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eHatipoglu S, Almogheer B, Mahon C, Houshmand G, Uygur B, Giblin GT, Krupickova S, Baksi AJ, Alpendurada F, Prasad SK, Babu-Narayan SV. Clinical significance of partial anomalous pulmonary venous connections (isolated and atrial septal defect associated) determined by cardiovascular magnetic resonance. Circulation: Cardiovascular Imaging. 2021 Aug;14(8):e012371.\u003c/li\u003e\n\u003cli\u003eEl-Kersh K, Homsy E, Daniels CJ, Smith JS. Partial anomalous pulmonary venous return: a case series with management approach. Respiratory medicine case reports. 2019 Jan 1;27:100833.\u003c/li\u003e\n\u003cli\u003eAbbara S, Kligerman S. Diagnostic Imaging: Cardiovascular-E-Book. Elsevier Health Sciences; 2025 May 6.\u003c/li\u003e\n\u003cli\u003eAli F, Qureshi S, Amanullah M, Atiq M. Accuracy of echocardiography in diagnosing total anomalous pulmonary venous return. Pakistan Journal of Medical Sciences. 2018 Sep;34(5):1094.\u003c/li\u003e\n\u003cli\u003eLei L, Zhou Y. Bilateral Partial Anomalous Pulmonary Venous Return. Radiology. 2025 Jun 10;315(3):e242606.\u003c/li\u003e\n\u003cli\u003eLatson LA, Prieto LR. Congenital and acquired pulmonary vein stenosis. Circulation. 2007 Jan 2;115(1):103-8.\u003c/li\u003e\n\u003cli\u003eEbrahimi P, Mandegar MH, Jafari Fesharaki M, Ghasemloo N, Ramezani P, Akbari T, Naderi F. Unusual presentation of a patient with partial anomalous pulmonary venous connections without a septal defect: a case report and literature review. International Journal of Emergency Medicine. 2025 Jan 7;18(1):6.\u003c/li\u003e\n\u003cli\u003ePatel HR, Bhutani S, Shamoon F, Virk H. Deciphering a case of pulmonary hypertension in a young female: Partial anomalous pulmonary venous drainage the culprit. Annals of Thoracic Medicine. 2018 Jan 1;13(1):55-8.\u003c/li\u003e\n\u003cli\u003eRahnama N, Kubangumusu L, Pasquet A, Robert A, Pouleur AC, Carbonez K, Kefer J, Moniotte S, Poncelet A, de Becco G, Ghaye B. Partial anomalous pulmonary venous return in adults: Insight into pulmonary hypertension. International Journal of Cardiology Congenital Heart Disease. 2023 Mar 1;11:100426.\u003c/li\u003e\n\u003cli\u003eNath R, Murphy W, Aronson B. Rare case of left upper lobe partial anomalous pulmonary venous connection. Journal of Radiology Case Reports. 2013 Jun 1;7(6):9.\u003c/li\u003e\n\u003cli\u003eAlsoufi B, Cai S, Van Arsdell GS, Williams WG, Caldarone CA, Coles JG. Outcomes after surgical treatment of children with partial anomalous pulmonary venous connection. The Annals of thoracic surgery. 2007 Dec 1;84(6):2020-6.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table 1","content":"\u003cp\u003eTable [1]: Comparison between total and partial anomalous pulmonary venous return\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"678\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 19.469%;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 39.823%;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePAPVR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40.708%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eTAPVR\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 19.469%;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePresentation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 39.823%;\"\u003e\n \u003cp\u003eLater in adult life\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40.708%;\"\u003e\n \u003cp\u003eSince birth\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 19.469%;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePathophysiology and hemodynamics\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 39.823%;\"\u003e\n \u003cp\u003eAnomalous connection of one or more of the pulmonary veins (more on the right side) to the systemic veins or the right atrium.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40.708%;\"\u003e\n \u003cp\u003eAnomalous connection of all pulmonary veins directly to the systemic veins or the right atrium.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 19.469%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eClassification and sub-categories\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 39.823%;\"\u003e\n \u003cp\u003e\u003cu\u003eClassified according to the number of anomalous veins and bilaterality into:\u003c/u\u003e\u003c/p\u003e\n \u003cul\u003e\n \u003cli\u003ePAPVR of the right pulmonary veins to the right atrium associated with secondum ASD.\u003c/li\u003e\n \u003cli\u003ePAPVR of the right pulmonary veins to the SVC or IVC with sinus venosus ASD.\u003c/li\u003e\n \u003cli\u003ePAPVR of the right pulmonary veins to the IVC with scimitar syndrome (Hypoplastic right lung and congenital venolobar syndrome).\u003c/li\u003e\n \u003cli\u003eMixed drainage to multiple sites with more than one anomalous pulmonary vein.\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40.708%;\"\u003e\n \u003cp\u003e\u003cu\u003eClassified according to the site of insertion of pulmonary veins:\u003c/u\u003e\u003c/p\u003e\n \u003col\u003e\n \u003cli\u003eSupracardiac (the most common): Left innominate vein, SVC and Azygous vein.\u003c/li\u003e\n \u003cli\u003eCardiac: Right atrium and Coronary sinus.\u003c/li\u003e\n \u003cli\u003eInfracardiac: IVC. Portal vein or left gastric vein.\u003c/li\u003e\n \u003cli\u003eMixed pattern.\u003c/li\u003e\n \u003c/ol\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 19.469%;\"\u003e\n \u003cp\u003e\u003cstrong\u003eAssociation\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 39.823%;\"\u003e\n \u003cul\u003e\n \u003cli\u003eHorseshoe lung.\u003c/li\u003e\n \u003cli\u003eAnomalies of the right hemidiaphragm.\u003c/li\u003e\n \u003cli\u003e\u0026nbsp;Anomalies of the bony thorax and soft tissues.\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 40.708%;\"\u003e\n \u003cp\u003eVisceral heterotaxy (right-sided isomerism)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 100%;\"\u003e\n \u003cul\u003e\n \u003cli\u003e\u003cem\u003ePAPVR: partial anomalous pulmonary venous return\u003c/em\u003e\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eTAPVR: total anomalous pulmonary venous return\u003c/em\u003e\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eSVC: superior vena cava\u003c/em\u003e\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eIVC: inferior vena cava\u003c/em\u003e\u003c/li\u003e\n \u003cli\u003e\u003cem\u003eASD: atrial septal defect\u003c/em\u003e\u003c/li\u003e\n \u003c/ul\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n"}],"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":"sn-comprehensive-clinical-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sncm","sideBox":"Learn more about [SN Comprehensive Clinical Medicine](https://www.springer.com/journal/42399)","snPcode":"42399","submissionUrl":"https://submission.nature.com/new-submission/42399/3","title":"SN Comprehensive Clinical Medicine","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Anomalous Pulmonary Venous Return, Echocardiography, Computed Tomography, Congenital Heart Disease","lastPublishedDoi":"10.21203/rs.3.rs-7729632/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7729632/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eIntroduction:\u003c/b\u003e\u003c/p\u003e\u003cp\u003ePartial anomalous pulmonary venous return (PAPVR) is a rare congenital anomaly that results in a left-to-right shunt. Bilateral PAPVR is extremely rare and is usually accompanied by an atrial septal defect (ASD).\u003c/p\u003e\u003cp\u003e\u003cb\u003eCase presentation:\u003c/b\u003e\u003c/p\u003e\u003cp\u003eWe present a rare case of bilateral PAPVR without ASD. A 56-year-old male patient presented to the cardiology department with atypical chest pain and congested neck veins. The patient underwent echocardiography, which revealed dilated right-sided cardiac chambers and a significant left-to-right shunt. There were no signs of intracardiac shunting by echocardiography as both atrial and ventricular septa were intact. An extra-cardiac left-to-right shunt was suspected, and the patient underwent an electrocardiogram (ECG)-gated cardiac computed tomography (CT), which revealed bilateral PAPVR. In this article, we highlight the role of ECG-gated CT in detecting complex congenital heart diseases, particularly when extra-cardiac blood shunting is suspected.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusions:\u003c/b\u003e\u003c/p\u003e\u003cp\u003eAlthough it is a rare cause of left-to-right shunt in the elderly, PAPVR should be considered, particularly when there is no evidence of an intracardiac shunt. It is important to note that PAPVR can occur without showing signs of pulmonary hypertension. ECG-gated CT is the preferred imaging modality when suspecting complex congenital cardiac anomalies due to its excellent spatial resolution.\u003c/p\u003e","manuscriptTitle":"Bilateral Partial Anomalous Pulmonary Venous Return with Intact Interatrial Septum: A Case Report and Review of Literature","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-23 02:45:34","doi":"10.21203/rs.3.rs-7729632/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-10-22T12:51:02+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-22T05:40:33+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-19T20:30:43+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-15T18:45:42+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"237978097373171330909992685861477005190","date":"2025-10-14T09:54:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"302057652997838131532408445407097328881","date":"2025-10-14T08:31:45+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"47960562032718618161048726250062293351","date":"2025-10-11T14:54:07+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"50062434327499277015433048601110114614","date":"2025-10-11T14:13:34+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-11T13:53:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-10-11T00:31:53+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"242957698313684718130040171565943679314","date":"2025-10-10T21:27:03+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"37229812870236251069495620963773023711","date":"2025-10-09T23:26:04+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"243860639575684801357060273595623401222","date":"2025-10-09T16:56:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"305610123383150968837400707661251031212","date":"2025-10-09T14:19:17+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-10-09T08:22:18+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-06T08:23:24+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-06T01:38:28+00:00","index":"","fulltext":""},{"type":"submitted","content":"SN Comprehensive Clinical Medicine","date":"2025-09-27T16:10:00+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"sn-comprehensive-clinical-medicine","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"sncm","sideBox":"Learn more about [SN Comprehensive Clinical Medicine](https://www.springer.com/journal/42399)","snPcode":"42399","submissionUrl":"https://submission.nature.com/new-submission/42399/3","title":"SN Comprehensive Clinical Medicine","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"6f440986-72d1-47b1-b5c8-90a2b8dd2c23","owner":[],"postedDate":"October 23rd, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-08T16:06:05+00:00","versionOfRecord":{"articleIdentity":"rs-7729632","link":"https://doi.org/10.1007/s42399-025-02184-9","journal":{"identity":"sn-comprehensive-clinical-medicine","isVorOnly":false,"title":"SN Comprehensive Clinical Medicine"},"publishedOn":"2025-12-02 15:57:12","publishedOnDateReadable":"December 2nd, 2025"},"versionCreatedAt":"2025-10-23 02:45:34","video":"","vorDoi":"10.1007/s42399-025-02184-9","vorDoiUrl":"https://doi.org/10.1007/s42399-025-02184-9","workflowStages":[]},"version":"v1","identity":"rs-7729632","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7729632","identity":"rs-7729632","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}