Elevated pre-transplant pulmonary vascular resistance is not associated with mortality in children without congenital heart disease: a multicenter study

Abstract

Background: Traditionally, an elevated pulmonary vascular resistance index (PVRI) has been a relative contraindication to pediatric orthotopic heart transplantation. This study examined the risk of elevated pre-transplant PVRI on early (30-day) and intermediate-term mortality in pediatric heart transplant recipients without congenital heart disease (CHD).

Methods: A review of the prospective multicenter Pediatric Heart Transplant Study registry identified all patients without CHD in whom a pre-transplant PVRI was recorded. Of 35 participating centers, 29 reported heart transplants in children with a markedly elevated PVRI (> 5 WU × m(2), corresponding to the highest quartile). Multiphase parametric analysis was performed, adjusting for potential risk factors to assess the association of PVRI with early and intermediate-term mortality.

Results: Between 1993 and 2011, 1,909 children without CHD underwent heart transplantation at a median age of 9.7 years (range, 1.6 months-18 years). Of those, 795 (42%) had a recorded or calculable pre-transplant PVRI, and PVRI > 5 WU × m(2) was present in 193 patients (24%). For all recipients, median pre-transplant PVRI was 3.15 WU × m(2) (range, 0.4-23 WU × m(2)); 2.8 WU × m(2) in infants < 1 year, 3.5 WU × m(2) in patients aged 1 to 10 years, and 3.0 WU × m(2) in patients aged > 10 years (p = 0.03). Multivariable hazard analysis controlling for graft ischemic time and pre-transplant ventilation showed no association of elevated PVRI with early mortality (relative risk, 1.2; p = 0.66), nor with intermediate mortality when controlled for year of transplant, age, race, and pre-sensitization (relative risk, 0.7; p = 0.27).

Conclusions: Elevation of PVRI did not affect post-transplant survival in this large, multicenter cohort of pediatric heart transplant recipients without CHD, suggesting that the barrier of elevated PVRI can be successfully overcome in this population.

Keywords: cardiomyopathy; heart transplant outcome; mortality; pediatric; pulmonary vascular resistance index.