Poor Left Ventricular Unloading is Associated with Increased Mortality after Continuous Flow Left Ventricular Assist Device Implantation

Abstract

Purpose The role of routine right heart catheterization (RHC) to evaluate for left ventricular (LV) unloading remains unclear in patients with continuous flow left ventricular assist devices (CF-LVAD). We hypothesized that persistently elevated pulmonary capillary wedge pressure (PCWP) would be associated with increased mortality on CF-LVAD support. Methods A single center continuous flow LVAD cohort (n=451) was queried for patients with follow-up RHC data at 6 months +/- 3 months (n=179). To determine the relationship between follow-up PCWP and mortality, a multivariable cox regression analysis was performed. Results The mean age of the study cohort was 57±13 years. 79% (141/179) were males, 56% (101/179) had ischemic cardiomyopathy and 74% (133/179) were designated bridge to transplant (BTT). The median follow-up time on LVAD support after RHC was 4.4 years. The only pre-implant variables that were associated with elevated PCWP in the multivariate analysis were renal function and BMI (each 2.5 unit increase in BMI was associated with an adjusted 0.6 mmHg increase in follow-up PCWP, 95% CI 0.2-0.9 mmHg, p=0.004; each 0.5 mg/dL increase in creatinine was associated with a 1.2 mmHg increase in follow-up PCWP, 95% CI 0.4-2.1, p=0.003). In the final multivariate models, each 5 mmHg increase in PCWP at the time of RHC was associated with a 22% increase in the hazards rate of death during follow-up (adjusted HR 1.2, 95% CI 1.01-1.47, p=0.039). All models were adjusted for age, sex, INTERMACS profile, body mass index, bridge to transplant status and renal function. Conclusion Incomplete LV unloading following CF-LVAD implantation is associated with increased all-cause mortality. Our results emphasize the importance of invasive hemodynamic optimization in this patient population. Further studies are warranted to determine the optimal filling pressures in patients with CF-LVAD.