The Challenge of Pediatric Heart Transplantation in a Failing Fontan Patient With Dextrocardia and Heterotaxy Syndrome

Introduction

Dextrocardia with heterotaxy syndrome and single ventricle represents a rare and heterogeneous subset of congenital heart disease (CHD). For these patients, the surgical journey typically involves multiple staged operations culminating in a Fontan circulation. However, long-term complications such as protein-losing enteropathy(PLE), ventricular dysfunction, and elevated pulmonary vascular resistance (PVR) may ultimately necessitate cardiac transplantation. ¹ We present a case of successful orthotopic heart transplantation (OHT) in a 12-year-old patient with dextrocardia, heterotaxy syndrome with right atrial isomerism, and single ventricle physiology following Fontan palliation.

Case Report

A 12-year-old female with complex CHD, including dextrocardia, heterotaxy with right atrial isomerism (RAI), and single ventricle physiology, presented with multiple congenital anomalies. These included right ventricular-dominant atrioventricular septal defect, total anomalous pulmonary venous return, malposed great arteries, and pulmonary stenosis. She had undergone staged palliation, which included a bilateral bidirectional Glenn procedure (BDG) in 2012, followed by an 18 mm nonfenestrated Fontan procedure and pulmonary venous confluence repair in 2018. Her clinical course was complicated by PLE, leading to thoracic duct decompression procedure in 2024.

Due to progressive heart failure with symptomatic tachycardia, worsening cyanosis, and poor functional status, the patient was listed for heart transplantation. Pretransplant imaging demonstrated dextrocardia, bilateral superior vena cavae (SVC), and a midline inferior vena cava (IVC) draining into the right atrium (Figure 1). Additionally, the patient's pulmonary veins drained anomalously into the right atrium. Pretransplant volumetric analysis using computed tomography (CT) imaging was performed to assess the available space for the donor heart. The patient underwent OHT, using a donor heart from a suitable donor.

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Figure 1.

Three-dimensional reconstructed cardiac CT images demonstrating pretransplantation and posttransplantation anatomy. CT, computed tomography.

The surgical approach included a midline sternotomy, with establishment of cardiopulmonary bypass through aortic, bilateral SVC, and IVC cannulation. Cardiectomy was performed in the standard fashion. The right and left SVC were transected. The extracardiac Fontan conduit was disconnected from both the main pulmonary artery (MPA) and the atrial cuff, which connected the left-sided hepatic veins and the midline IVC. The common atrium, including the confluence of pulmonary veins, was preserved. The MPA defects were joined to create a single large defect, which was reconstructed using a 24 mm PECA graft tailored to patch the area. The PECA graft was chosen due to its low risk of kinking and its capacity to accommodate future dilatation if necessary. The conduit was intentionally left long in anticipation of donor heart implantation.

The donor aorta was separated from the MPA as proximally as possible to reduce the risk of pulmonary artery kinking after implantation. Given the extracardiac position of the native heart, leftward location of the hepatic veins, and rightward location of the pulmonary venous confluence, the donor heart was positioned with the left anterior descending artery oriented slightly rightward. The heart was rotated counterclockwise to optimize alignment with the recipient's IVC. The left atrial cuff anastomosis was performed first using a running 4-0 Prolene suture in a clockwise fashion, beginning near the anticipated site of the recipient IVC. A left heart vent was placed via the left atrial appendage using a purse-string suture with a snare. To accommodate the diameter discrepancy and complex anatomy of the recipient's hepatic veins and IVC, an incision was made from the donor IVC onto the right atrium. The donor IVC was then anastomosed to the recipient's IVC using a 5-0 Prolene suture.

The donor aorta was trimmed to the appropriate length and anastomosed to the recipient's ascending aorta in proper orientation. The left heart was de-aired, and the aortic cross-clamp was removed to allow reperfusion. Rewarming was initiated, and the donor heart resumed spontaneous sinus rhythm. The donor MPA was appropriately oriented and anastomosed to the previously constructed PECA graft. The graft was slightly trimmed for appropriate fit and orientation. This alignment was necessary due to the posterior and rightward position of the MPA relative to the aortic root following implantation.

The donor heart had been procured with both right and left brachiocephalic veins. The right brachiocephalic vein was anastomosed to the recipient's right SVC. The left SVC was anastomosed to a 14 mm Gore-Tex tube graft using a running Prolene suture (Figure 2). This graft was tunneled in a retro aortic position and anastomosed end-to-side to the recipient's innominate vein.

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Figure 2.

Intraoperative stages of donor heart implantation in a patient with dextrocardia; (A) Dissection of the Fontan conduit, (B) Separation of the central pulmonary artery (PA) from the Fontan and Glenn anastomoses, (C) Anastomosis of the pulmonary graft to the central PA, (D) Completion of the inferior vena cava anastomosis, (E) Anastomosis between the donor pulmonary artery and the pulmonary graft, (F) Retroaortic view of the left superior vena cava graft and final appearance of the transplant. Abbreviations: IVC, inferior vena cava; LSVC, left superior vena cava; PA, pulmonary artery.

Delayed sternal closure was performed on postoperative day 3. The patient was maintained on low molecule weight heparin for systemic anticoagulation postoperatively. The patient's chest x-ray demonstrated persistent dextrocardia postoperatively (Figure 3). She was discharged on postoperative day 16 in stable condition.

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Figure 3.

Imaging of preoperative and postoperative cardiac position in dextrocardia; (A) Preoperative CT slice showing dextrocardic orientation, (B) Preoperative chest X-ray, (C,D) Posttransplant imaging showing maintained dextrocardic position.

Discussion

Dextrocardia is a rare form of CHD characterized by the abnormal positioning of the heart, where the heart is positioned with its apex pointing toward the right side of the chest. This anomaly significantly complicates heart transplantation because it creates a mismatch between the donor heart and the recipient's anatomical configuration. ² Various surgical techniques have been developed to address these challenges. Reinhartz et al ³ presented their experience with 5 patients with dextrocardia and reported 1 case of transplant-time mortality. In a case report by Pradegan et al, ⁴ they described performing heart transplantation in a 44-year-old patient with dextrocardia, who was discharged in the 3rd postoperative month. Boston et al, ⁵ in another report, emphasized the importance of detailed preoperative planning—including CT volumetric analysis to determine appropriate donor size and meticulous reconstruction of venous pathways—as critical factors for successful OHT in small infants with dextrocardia and heterotaxy syndrome. By rotating the donor heart to accommodate the abnormal positioning of the recipient's chest, surgeons can avoid complications such as pericardial resection, lung compression, and right ventricular compromise—common issues encountered in previous transplantation techniques.

Furthermore, our approach emphasized the importance of leaving a sufficiently long portion of the aorta and pulmonary artery during donor heart excision, which aids in ensuring that the heart can be positioned correctly in the recipient's chest without excessive tension on the vascular connections. The use of vascular prostheses and systemic atrial cuffs in the venous anastomoses also allowed for optimal reconstruction of the systemic venous pathways, an essential step in ensuring proper venous return to the newly transplanted heart. Huddleston et al ⁶ reported employing a different surgical approach to avoid the use of synthetic grafts. In their technique, the right and left pulmonary arteries are left attached to the MPA. The strategy for redirecting the left SVC to the right is to utilize this mediastinal pulmonary artery as an “innominate vein.”

While the technical success of this approach is promising, the morbidity and mortality rates for Fontan patients undergoing heart transplantation are higher than for patients with non-Fontan CHD, primarily due to the unique hemodynamic challenges posed by the Fontan circulation. Preoperative evaluation is critical to identify potential complications, such as pulmonary arteriovenous fistulas and increased PVR, that could complicate the transplantation process. For these patients, the decision between heart transplantation alone or heart-lung transplantation is a subject of ongoing debate, and more research is needed to determine the most appropriate approach. Early postoperative complications, such as infections or rejection, can exacerbate the already fragile hemodynamics of Fontan failure patients, making close monitoring essential.

In our case, despite the technical challenges presented by dextrocardia and Fontan failure, the patient had a successful transplantation. We would like to express the importance of accurate preoperative imaging and pulmonary evaluation to ensure that these conditions are addressed during surgery. Postoperative outcomes for patients with Fontan failure remain difficult to predict, and more long-term data are needed to assess the viability of transplantation in this patient population fully.

Conclusion

Heart transplantation in patients with dextrocardial CHD is a rare and complex procedure that presents significant challenges. Our approach, which involves rotating the left atrium, performing an end-to-end aortic anastomosis, and using vascular prostheses for venous reconstruction, has proven to be a straightforward and effective method. Early outcomes in our patient have been promising, particularly for those with dextroversion. However, further long-term follow-up is necessary to fully assess the outcomes of this technique.

While heart transplantation for patients with dextrocardial CHD remains technically challenging, our experience suggests that with careful planning and attention to detail, favorable results can be achieved. The long-term survival and quality of life for these patients require ongoing monitoring and tailored interventions to address the unique complexities of their conditions.