Hemodynamic Reserve Predicts Early Right Heart Failure After LVAD Implantation

Abstract

Background Right heart failure (RHF) remains a major source of morbidity and mortality after left ventricular assist device (LVAD) implantation, yet efforts to predict RHF have proved only modestly successful. Acute pharmacologic unloading of the LV to assess ventricular and hemodynamic reserve may better predict post-implant RHF. Objectives To compare pre-implant baseline and post-vasodilator hemodynamic predictors of INTERMACS defined severe or severe-acute RHF after LVAD implantation. Methods After IRB approval, we performed a retrospective analysis of all subjects implanted with a durable LVAD at our institution between February 2017 and April 2020 (n=108). Only those who underwent vasodilator testing with nitroprusside during their pre-implant right heart catheterization were ultimately included (n=29). Continuous variables were compared with t-test and Levene's test of equality of variances; categorical via Fisher's Exact test. Logistic regression was used to determine predictors of severe or severe-acute RHF. Results Ten subjects met criteria for severe or severe-acute RHF (34%) after implant. There were no significant differences in demographics, HF etiology, INTERMACS profile, echo assessment of LV/RV function, or pre-implant baseline hemodynamics including RAP:PAWP ratio and PAPi between groups (TABLE). Both groups saw a similar reduction in systemic mean arterial pressure with nitroprusside, which led to significant and similar reductions in PAWP and pulmonary pressures. Compared to the group with severe or severe-acute RHF, those without significant RHF achieved higher peak cardiac index (CI) with nitroprusside infusion, suggesting better cardiac reserve. Peak CI was a significant predictor of RHF (p= 0.022), even after controlling for baseline values (p=0.048). No subject achieving a peak CI > 2.66 L/min/m2 developed severe or severe-acute RHF, and every 0.25 L/min/m2 decrease in peak CI was associated with 2.3 fold increased risk. Mortality was higher and hospital length of stay longer in the severe or severe-acute RHF group. Conclusion Peak CI with nitroprusside infusion predicts post-implant LVAD RHF better than resting hemodynamics in this small cohort. Hemodynamic reserve measurements may prove to be an important risk stratification tool when assessing LVAD candidacy.