(331) - Hemodynamic Response to Nitroprusside as Predictor of Right Ventricular Failure After LVAD Implantation

Abstract

Left ventricular assist devices (LVADs) have emerged as a standard of care for patients with end stage heart failure refractory to medical therapy. Right ventricular (RV) failure is a major cause of morbidity and mortality following LVAD implantation. This study aims to determine if nitroprusside (NTP) induced hemodynamic changes can predict acute right ventricular failure after LVAD implantation. A cohort of 100 patients who received NTP with hemodynamic monitoring prior LVAD implantation were retrospectively evaluated. Hemodynamic parameters included pulmonary vascular resistance (PVR), mean pulmonary (mPA), wedge, right atrial (RA), and mean arterial (MAP) pressures, cardiac index (CI), and RV stroke work index (RVSWI). A response to NTP was considered adequate by previously accepted parameters which include decreases in PCWP to 18 mmHg, mean pulmonary arterial pressure (mPAP) by at least 20%, and right atrial pressure to 8 mmHg, improvement in CI to 2.2 l/min/m2, and maintenance of MAP 65 mmHg. RV failure was defined as need for post-operative ionotropic support > 14 days, extracorporeal membrane oxygenation (ECMO) support, or right ventricular assist device (RVAD). Of 100 patients with LVAD implants and prior NTP administration with invasive hemodynamic monitoring, 28 developed RV failure. Prior to NTP administration, there was no difference in PVR (4.1mm Hg vs 4.0), RA (12mmHg vs 11 mmHg), Wedge (25 mmHg vs 25 mmHg), MAP, CI (2.1 vs 2.0), or RVSWI (15.3 vs 8.4) in patients who developed RV failure and those who did not, respectively. However, the group that developed RV failure did have a higher mPA pressure (30 mmHg vs 26 mmHg, p = 0.03) after NTP. PVR, RA pressure, wedge, MAP, and CI were similar after NTP administration in patients who developed RV failure and those who did not. Furthermore, comparing patients who had at least a 20% decrease in mPA pressure after NTP administration to those whose mPA pressure did not decrease, did not predict mortality during follow-up period of up to 1040 +/- 447 days, p=0.49. Multiple predictors of RV failure post LVAD implantation have been previously suggested. In this study, sustained elevation in mPA pressure after administration of NTP was associated with increased risk of RV failure. Otherwise, NTP induced hemodynamic changes in PVR, RA, and Wedge pressures did not predict RV failure.