Abstract 11886: Unique Insights of Pressure-Volume Loop Analysis During LVAD Ramp Study

Abstract

Introduction: Late right ventricular (RV) failure in left ventricular assist device (LVAD) patients leads to poor outcomes and mortality. Traditional hemodynamic assessment of RV function may lack sensitivity. Invasive pressure-volume loop assessment of RV function may prove more enlightening than currently available measures. Methods: Pressure-volume loop-derived RV end-systolic elastance (Ees) and effective arterial elastance (Ea)—indices of load-independent RV contractility and summated pulmonary arterial (PA) afterload respectively—were determined for control (n=14), PH (n=38), and LVAD (n=12) patients referred for right heart catheterization. LVAD patients were further dichotomized by referral reason: routine assessment vs. clinical heart failure (HF) (n=6 each). Results: At baseline, LVAD patients had lower RV Ees versus both PH (0.21 vs 0.41 mmHg/mL, p<0.001) and control (0.21 vs. 0.36 mmHg/mL, p=0.05) patients. Adjusting for age and afterload, RV-PA coupling, indexed by the ratio of Ees/Ea, was significant lower in LVAD vs matched non-LVAD patients (0.37 vs 0.65, p=0.01). Among LVAD patients, RV-PA coupling was significantly worse in those with clinical HF (0.26 vs 0.49, p=0.002), corresponding with depressed cardiac index (1.6 vs 2.3 L/min/m 2 , p=0.04) and a trend towards higher biventricular filling pressures. RV-PA coupling also responded differently with respect to speed change: while Ees/Ea improved with speed increase in well-compensated LVAD patients, it declined in those with HF (p=0.02 for interaction term, see Figure), driven by declining Ees. Conclusion: Intrinsic RV contractility is worse in LVAD patients versus control and non-LVAD PH; this drives significantly worse RV-PA coupling in LVAD patients. In LVAD patients with HF, RV-PA coupling is significantly reduced and not necessarily improved by increases in speed.