Heart transplantation in children with markedly elevated pulmonary vascular resistance: impact of right ventricular failure on outcome.

BACKGROUND: Pulmonary hypertension causes increased morbidity and mortality in adults after heart transplantation. The effect of markedly elevated pulmonary vascular resistance (PVR) on post-transplant outcomes in children has not been well described.
METHODS: Outcomes were compared in a retrospective study between 58 children with an elevated PVR index (PVRI) ≥ 6 U/m(2) and 205 children with a PVRI < 6 U/m(2). Patients who did and did not respond to acute vasodilator testing and patients who underwent transplant before (pre-1995) and after (post-1995) the availability of inhaled nitric oxide (iNO) were compared.
RESULTS: The pre-transplant diagnoses, and cardiopulmonary bypass and donor ischemic times were similar between the high and low PVRI groups. High PVRI patients were older at transplant (12 ± 6.2 vs 8 ± 7.1 years, p = 0.002). The post-transplant inotrope score was higher in the high PVRI group (12 ± 12 vs 2 ± 2, p = 0.0001) and 1-year survival was worse (76% vs 81%, p = 0.03). The PVRI fell to < 6 U/m(2) with acute vasodilator testing in 21 of 49 (42%) high PVRI patients. RV failure occurred in 4 (19%) of the responders and in 14 (50%) of the non-responders (p = 0.037). One responder (5%) and 4 non-responders (14%) died of RV failure. In the period after 1995, the year iNO became clinically available, the select group of high PVRI patients who received iNO preemptively had a lower incidence of post-transplant RV failure than the group that did not receive preemptive iNO (13% vs 54%, p = 0.04).
CONCLUSIONS: Pre-transplant vasodilator testing identified patients at higher risk for RV failure. Patients who did not respond to vasodilator testing had an increased incidence of RV failure and death from RV failure. Preemptive use of iNO was associated with a decreased incidence of RV failure.