Cardiac Power Output and Cardiac Power Efficiency Show Prognostic Value in LVAD Patients

Abstract

<h3>Purpose</h3> Hemocompatibility-related clinical adverse events (HRAE) are thought to be driven by the pump-patient interaction. We hypothesized that the hemodynamic variables cardiac power output (CPO) and cardiac power efficiency (CPE), which reflect underlying ventricular contribution, have prognostic value in patients with left ventricular assist devices (LVADs). <h3>Methods</h3> Prospectively collected hemodynamic data from patients with LVADs who had undergone invasive hemodynamic ramp study at our institution between 4/2014-7/2018 were analyzed. CPO [(mean arterial pressure x cardiac output)/451], cardiac power index (CPI) (CPO/body surface area), and CPE (CPI/ pulmonary capillary wedge pressure) were calculated. Patients were divided into groups of high and low CPO and CPE using ROC-derived cutoff values of 0.847W and 0.0552 WmmHg/m² respectively. Hemocompatibility scores (HCS) were also calculated for each patient based on their HRAE. Univariate and multivariate logistic regression analyses were performed to determine the association between CPO and CPE with primary endpoints of HRAE, HCS, heart failure readmissions, and mortality. <h3>Results</h3> 91 patients (average age 61 ± 11 years, 34% women, 40% Black, 38% ischemic cardiomyopathy) were included in the analysis. Low CPO was significantly associated with higher rates of HRAE, HR 2.02 (95% CI 1.12-3.66, p=0.02, Figure 1A). CPO was not significantly associated with mortality or heart failure readmission, HR 1.84 (95% CI 0.68-3.32, p=0.31) and HR 1.84 (95% CI 0.92-3.68, p=0.083), respectively. Low CPE was significantly associated with higher rates of HRAE, heart failure readmission (Figure 1B), and mortality (Figure 1C) when adjusted for LVAD type: HR 1.97 (95% CI 1.02-3.81, p=0.043), HR 3.11 (95% CI 1.28-7.58, p=0.012), and HR 3.41 (95% CI 1.18-9.88, p=0.024), respectively. <h3>Conclusion</h3> CPO and CPE demonstrate prognostic value in patients with LVADs, showing significant associations with HRAE, heart failure readmissions, and mortality.