Lung Transplantation for Pulmonary Hypertension and Strategies to Bridge to Transplant
Despite an expanded armamentarium of medical therapies, pulmonary arterial hypertension (PAH) remains a progressive disease associated with significant morbidity and premature mortality. Lung transplantation (LT) is the last safety net for patients failing medical therapy, providing excellent overall long-term survival and health-related quality-of-life outcomes in line with more common parenchymal lung disease indications. Waitlist mortality remains disproportionally elevated, however, reflecting an inability of the lung allocation score to completely capture PAH disease severity, and a propensity for PAH to deteriorate rapidly without warning, even in patients who appear externally “well.” Early referral to a LT center can mitigate these risks and facilitate rapid listing if necessary. Several bridging therapies are available to support severely unwell patients to LT, such as extracorporeal life support (ECLS) and atrial septostomy. Unique perioperative considerations include higher rates of primary graft dysfunction and dynamic right ventricular outflow obstruction which may, at least in part, reflect rapid afterload reduction in the face of a conditioned right ventricle. Extending ECLS into the perioperative period may ameliorate these risks by allowing more gradual adaptation of both ventricles to their new loading conditions. Chronic lung allograft dysfunction, particularly bronchiolitis obliterans syndrome, remains a major cause of long-term morbidity and mortality, and complications from corticosteroid and immunosuppressive therapy are common. Nevertheless, the morbidity, mortality, and burden of disease management after LT continue to improve and compare favorably to that of refractory PAH in carefully selected patients.