Hemodynamic Parameters That Predict Success with an Ambulatory Counterpulsation Heart Assist System in Advanced Congestive Heart Failure

Abstract

Purpose The intravascular ventricular assist system (iVAS) is a long-term, ambulatory counterpulsation heart assist system designed for long term use in patients with advanced congestive heart failure (aCHF). A feasibility trial has been conducted and early analysis showed several pre-implant parameters, particularly cardiac power efficiency (CPE), could predict hemodynamic success. The data has been reanalyzed with completion of the trial. Methods A multicenter, US FDA approved feasibility trial enrolled 44 patients with aCHF to receive the iVAS device as a bridge to transplant or decision. Hemodynamic parameters, including CPE, were collected pre-implantation. CPE is defined as the cardiac power index (CPI) divided by the pulmonary capillary wedge pressure (PCWP). Patients were optimized with inotropes or intra-aortic balloon pumps (IABP). Patients had hemodynamic success (HS) if they were weaned off inotropes and had clinically acceptable hemodynamics. The success (HS) and non-success (NHS) groups were compared. Results Demographics were as follows: the average age was 58.9 ± 7.7, 82% were male, 48% had ischemic cardiomyopathy, the mean pre-operative left ventricular ejection fraction was 23.6 ± 10.7, and 86% were on inotropes and/or an IABP. HS was achieved in 30 patients, 69.8%, with 13 NHS patients, 30.2%. Table 1 displays pre-implant hemodynamics in both groups. While many parameters differed between groups, the most predictive parameter was CPE with an area under the receiver operator curve of 0.986. A CPE cutoff of ≥ 0.0175 has a sensitivity of 92.6% and specificity of 100%. Conclusion Cardiac reserve is required for a counterpulsation device to be effective. This study further supports the use of CPE as a very accurate predictor of hemodynamic success with the iVAS device. This parameter combines power and preload to better assess a patient's cardiac reserve and improve patient selection.