Top Things to Know: Top Things to Know
Published: December 09, 2024
- In pulmonary hypertension (PH) due to left heart disease, the primary driver is systolic or diastolic dysfunction of the left ventricle, leading to left atrial hypertension and pulmonary venous congestion. Over time, the pulmonary arterial bed may remodel, causing elevated pulmonary vascular resistance (PVR).
- Elevated PVR after heart transplant may increase strain on the right ventricle, potentially leading to acute right heart failure—an important factor for heart transplant eligibility.
- While some studies have correlated post-transplant mortality with elevated pre-transplant PVR, few studies have examined whether mortality actually resulted from PH/right heart failure. The degree of risk associated with elevated pre-transplant PVR in children undergoing heart transplantation remains unknown.
- PVR assessment is standard in heart transplant evaluations, but there's little consensus on thresholds for listing, especially in children. As a result, some children with elevated PVR may undergo a combined heart-lung transplant, which has a worse long-term survival prognosis.
- Many centers consider a PVR of <6 indexed Woods Units as required for heart transplant eligibility, which may be obtained by acute vasodilator testing with nitric oxide or other agents. However, many centers do not use a cutoff and considerable practice heterogeneity exists.
- PVR and response to acute vasodilator testing are important to consider in the context of complete hemodynamic data. Some centers include both transpulmonary pressure gradient (mean or diastolic) and indexed PVR as criteria for heart transplant evaluation.
- While most published adult-based guidelines do not recommend routine use of pulmonary vasodilators in PH associated with left heart disease due to lack of evidence and risk of clinical worsening, some pediatric centers have reported successful use of pulmonary vasodilators to reduce PVR prior to heart transplant in children.
- Optimization of left heart failure management is imperative prior to consideration of pulmonary vasodilator use in children awaiting heart transplant, given the risks of clinical worsening and that PVR may improve by reducing left atrial pressure alone.
- Insufficient data exist to guide the approach to serial cardiac catheterization for children awaiting heart transplantation in terms of frequency, utility of repeat acute vasodilator testing, and overall prognostic value. When evaluating cardiac catheterization, it's important to consider the potential risks and benefits on an individual basis.
- PVR typically drops quickly after heart transplantation, often within weeks. Pulmonary vasodilators may be used to treat elevated PVR post-transplant but specific indications for therapy and duration of treatment still need to be defined.
Citation
Hopper RK, Hansmann G, Hollander SA, Dipchand AI, van der Have O, Iler C, Herrington C, Rosenzweig EB, Alejos JC, Tran-Lundmark K; on behalf of the American Heart Association Council on Cardiopulmonary, Critical Care, Perioperative & Resuscitation; Council on Clinical Cardiology; and Council on Cardiovascular Stroke Nursing. Clinical management and transplant considerations in pediatric pulmonary hypertension due to left heartdisease: a scientific statement from the American Heart Association. Circ Heart Fail. Published online December 9, 2024. doi: 10.1161/HHF.0000000000000086