Rescuing the Right Ventricle: Mechanical Support After Pediatric Heart Transplantation

Abstract

Background: Right ventricular (RV) failure after heart transplantation (HT) is common in those with pretransplantation elevated pulmonary vascular resistance (PVR). Mechanical circulatory support has been used as a bridge to recovery, with mixed outcomes. We describe a patient with failed single-ventricle palliation in whom severe RV failure developed after HT. We review the current literature and outline our post-HT strategy.

Methods: An infant with trisomy 21, severely unbalanced right dominant atrioventricular septal defect, and hypoplastic aortic arch was palliated with a hybrid procedure. At 6 months of age, cardiac catheterization measured PVR index of 5.47 Wood units × m² on maximal medical therapy. The patient was deemed unsuitable for second-stage palliation and underwent HT at 18 months of age. Despite preemptive medical therapies, acute RV failure developed, necessitating extracorporeal membrane oxygenation. He was quickly converted to main pulmonary artery to left atrial cannulation. Unloaded RV function normalized; he was weaned from support and discharged home 5 weeks after HT.

Results: Failure of medical therapy in RV failure after HT requires escalation to mechanical circulatory support. We review the literature on RV failure and support after HT. We also describe a novel cannulation strategy to provide a reliable way to directly reduce RV afterload, to allow physiologic training of the right ventricle to a higher PVR, and to maintain normal left ventricular coupling and loading.

Conclusions: In pediatric patients with elevated PVR undergoing HT, advanced therapies can be used effectively to treat acute RV failure. Unique cannulation strategies may play a role in improving survival of similar patients.

Graphical abstract

Figure 1

Schematic for pulmonary artery (PA) to left atrium (LA) extracorporeal membrane oxygenation. Note: In addition to the depicted setup, a Dacron chimney tube graft can be employed for improved cannula positioning.

Figure 2

Echocardiographically obtained right ventricular systolic pressure (RVSP) measurements using the tricuspid regurgitation jet are shown (solid blue line). Corresponding simultaneous systolic blood pressure (SBP) measurements are shown by the orange line. In addition, the vasoactive inotropic score (VIS) is shown on the gray line. Linear trend line for the RVSP measurement is shown by the dashed blue line. Significant events are shown by dashed black arrows. (ECCO₂R, extracorporeal carbon dioxide removal; ECMO, extracorporeal membrane oxygenation; iNO, inhaled nitric oxide; LPA, left pulmonary artery; PA-LA, pulmonary artery–left atrium; POD, postoperative day; VA, venoarterial.)