Mildly Elevated Pulmonary Artery Systolic Pressure is Associated with Extracorporeal Membrane Oxygenation Support after Heart Transplantation

Abstract

Background. Pulmonary hypertension is a well-known risk factor for hemodynamic instability after heart transplantation. However, it remains unclear whether a mild elevation of pulmonary artery systolic pressure (PASP) is associated with higher risks of graft dysfunction and resultant extracorporeal membrane oxygenation (ECMO) support. Methods. From 2016 to 2021, 102 adult recipients undergoing orthotopic heart transplantation at our institution were investigated (mean age, 48.5 ± 13.2 years; 22.5% female). This study cohort was stratified into 3 groups based on the PASP measured by right heart catheterization before surgery: >50 mmHg, 35–50 mmHg, and <35 mmHg. The primary end point was ECMO support after procedure. Results. ECMO was implemented in 24 (23.5%) patients due to difficult weaning from cardiopulmonary bypass or cardiac low output in the intensive care unit, which was likely to be associated with higher mortality ( $P=0.053$ ). Age, gender, comorbidities, preoperative medications, and graft ischemia time were comparable across the 3 groups. The use of ECMO was significantly more common in patients with baseline PASP >50 mmHg (11/36, 30.6%) and 35–50 mmHg (12/38, 31.6%), while only 1 (3.6%) patient with baseline PASP <35 mmHg required ECMO support after transplant ( $P=0.007$ ). Multivariate logistic models demonstrated that PASP (odds ratio = 2.34; $P=0.028$ ) and cardiopulmonary bypass time (odds ratio = 1.01; $P<0.001$ ) were independent risk factors for postoperative ECMO. Conclusions. A mild elevation of pretransplant PASP (e.g., 35–50 mmHg) is related to low cardiac output and subsequent ECMO after heart transplantation, for which prompt administration of vasodilators before transplant may be protective.