Pre-Explant Stability of Unloading-Promoted Cardiac Improvement Predicts Outcome After Weaning From Ventricular Assist Devices

Abstract

Background— Detection of cardiac recovery that allows long-term cardiac stability after ventricular assist device (VAD) explantation is a major goal. After normalization of ventricular diameters during unloading, the pre-explant left ventricular ejection fraction (LVEF) allows the detection of patients with the potential to remain stable after VAD explantation. However, some patients with LVEF >45 before VAD explantation show early recurrence of heart failure (HF). We aimed to find out if unstable improvement can be recognized before VAD explantation. Methods and Results— Among 96 patients weaned from VADs since 1995, a relatively homogenous group of 53 patients with nonischemic chronic cardiomyopathy (CCM) was selected for the study. The pre-explant stability of major parameters of LV function, size, and geometry that were measured by echocardiography during serial “off-pump” trials was tested for relationship with cardiac stability after VAD explantation. LVEF, systolic peak wall motion velocity (Sm), end-diastolic diameter (LVEDD), end-diastolic relative wall thickness (RWT ED ) and end-diastolic short/long-axis ratio (S/L ED ) were selected for evaluation. In postweaning unstable patients, the selected parameters showed relevant instability already before VAD explantation during the time period between best cardiac improvement and VAD explantation and also during the final off-pump trial just before VAD explantation. For all parameters, there were significant differences ( P <0.05) in pre-explant changes between patients with and without postweaning cardiac stability. Using the optimal cutoff values obtained from receiver-operating characteristic analysis, we found for our selected parameters predictive values for postexplant cardiac stability of ≥1 year, ≥3 years, and ≥5 years, ranging between 94 and 100, 92, and 100, and 78 and 100, respectively. Using for all parameter changes the cutoff value of 10, we found similar predictive values for cardiac stability of ≥1 year, ≥3 years, and ≥5 years, ranging between 93 and 97, 90 and 96, and 83 and 92, respectively. Conclusions— Our results strongly suggest the possibility to improve the prediction of postexplant transplant/VAD-free outcome in CCM patients with cardiac improvement during VAD support by analyzing the pre-explant stability of several LV off-pump echocardiographic parameters during serial off-pump trials.