International Practice Heterogeneity in Pediatric Left Heart Disease Related Pulmonary Hypertension

Purpose

Elevated pulmonary vascular resistance (PVR) in left heart disease contributes to poor outcomes after pediatric heart transplant (HT). Medical management of high PVR pre-HT is controversial and insufficiently described.

Methods

We sought to characterize practice internationally by surveying physicians at pediatric HT centers via ISHLT and other networks.

Results

We received 49 complete responses from 39 centers in 16 countries. The majority of respondents were pediatric cardiologists (90%) practicing at centers offering pediatric heart (86%) and lung (55%) transplant. In patients with left heart failure and elevated baseline PVR, most centers (88%) perform acute vasoreactivity testing (AVT) during catheterization. Only half (51%) have established a maximum PVR for transplant eligibility, with most citing 6 WU*m² or lower (80%) [range 4-8 WU], obtained after AVT (84%). The highest post-AVT PVR ever listed ranged from 4-14.4, median 6 WU*m² (Figure). Pre-HT, phosphodiesterase 5 inhibitors are most frequently used to treat high PVR (65%); however, 31% never use pulmonary vasodilators. Implantation of a left ventricular assist device (LVAD) increases likelihood of medical therapy for PVR, though timing of initiation (pre- vs post-HT) and duration of therapy varies. Case scenarios demonstrate HT listing with post-transplant pulmonary vasodilator therapy is the favored approach for restrictive cardiomyopathy and elevated PVR, whereas LVAD +/- pulmonary vasodilators is favored for patients with dilated cardiomyopathy or postop LV dysfunction and high PVR, regardless of vasoreactivity. Most continue vasodilator therapy until PVR normalizes or short term (<6 months) post-transplant.

Conclusion

Practice regarding medical management of elevated PVR in children awaiting HT is heterogenous, with variable use of pulmonary vasodilators and a wide range of acceptable PVR cutoffs. Evidence-based guidelines are needed to ensure standardized care and equitable organ allocation.