High Afterload Driving Poor Cardiac Output in LVAD Patients is Rectified with Nitrate Therapy

Abstract

Purpose There is a paucity of data describing influences on cardiac output in patients supported on LVAD therapy. We describe, for the first time, the independent impact of afterload on cardiac output in the LVAD population. Methods Between 2015 and 2018, 54 patients on LVAD therapy were evaluated with simultaneous left and right heart catheterization ramp study. All patients with significant aortic regurgitation or device malfunction/thrombosis were excluded. Hemodynamic parameters from the 30 remaining patients undergoing speed optimization were analyzed. Results Mean central aortic pressure (MAP) was 87 ± 13 mmHg at baseline and correlated significantly with RPM for each pump type (R > 0.24, p ≤ 0.05 for all). No association between MAP or RPM and cardiac index (CI) was found. However, there was a significant correlation between systemic vascular resistance (SVRi) and CI (R = -0.76, p 90, n=8) received nitrate therapy and experienced a mean increase in cardiac index from 2.3 L/min/m2 to 2.8 L/min/m2 (mean increase of 23%) at a given RPM, validating the physiologic afterload findings. Conclusion Afterload as measured by LV-EA or SVRi negatively influences cardiac output in LVAD therapy and is ameliorated by nitrates. These findings serve as a foundation to evaluate the dynamic effects of high afterload and chronic vasodilator therapy in patients with durable LVADs.