Inhaled Pulmonary Vasodilator Therapy for Management of Right Ventricular Dysfunction after Left Ventricular Assist Device Placement and Cardiac Transplantation

Abstract

Right ventricular failure (RVF) after cardiac transplant (CTX) or implantation of a continuous-flow left ventricular assist device (CF-LVAD) is associated with significant postoperative morbidity and mortality. A variety of modalities have been used to treat postoperative RVF, including management of volume status, intravenous inotropes and vasodilators, and right-sided mechanical support. Inhaled vasodilator agents are a unique treatment option aimed at minimizing systemic absorption by delivering therapy directly to the pulmonary vasculature. Current LVAD and CTX guidelines endorse inhaled vasodilators for managing postoperative RVF; however, no guidance is offered regarding agent selection, dosing, or administration. A review of the current literature confirms that inhaled pulmonary vasodilator agents have been shown to decrease pulmonary artery pressure when used in the perioperative period of CF-LVAD implant or CTX. However, the literature regarding the potential impact on clinical outcomes (e.g., survival or risk of developing RVF) is lacking with these medications. Based on our assessment of the literature, we suggest that when RVF occurs in the setting of a normal pulmonary vascular resistance (PVR), traditional inotropic therapy (e.g., dobutamine) should be used. Conversely, if the PVR is elevated (> 250 dynes/sec/cm⁵ or 3 Wood units), or the patient has other evidence of a high right ventricular afterload (i.e., a transpulmonary gradient > 12 mm Hg), then an inhaled pulmonary vasodilator would be the preferred initial pharmacologic agent. Drug selection depends largely on the institution's capacity to safely prepare and administer the medication, along with formulary considerations, such as the high costs associated with inhaled iloprost and inhaled nitric oxide.

Keywords: heart transplantation; inhaled pulmonary vasodilators; left ventricular assist device; pulmonary arterial hypertension; right heart failure.