Left Ventricular Assist Device Explantation Evaluation Protocol Using Comprehensive Cardiopulmonary Exercise Testing
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Left ventricular assist devices (LVADs) provide decongestion of the left ventricle (LV) with associated reversal of cardiomyocyte hypertrophy, restoration of adrenergic receptor density, and improvement in calcium handling. Unfortunately, translation of these changes into definitive functional recovery at the organ level is infrequent. Reports of LVAD explantation rates because of cardiac recovery are highly variable depending on heart failure (HF) pathogenesis and weaning criteria used, with reported rates ranging from 4.5% to 45%.1 Institution-specific LVAD explantation evaluation protocols exist that use various hemodynamic, imaging, and gas exchange measurements in any combination. However, protocols that provide comprehensive assessment of myocardial performance under dynamic loading conditions and in response to the highly relevant physiological stress of exercise are lacking. The high reported rates of HF recurrence after LVAD explantation provide further motivation to carefully assess cardiac reserve capacity before explantation. This case series describes the use of a novel protocol in 2 patients, which integrates assessments of hemodynamic, imaging, and gas exchange measures during the state of rest, LVAD speed reduction, and exercise to uniquely characterize cardiac reserve capacity and guide LVAD explantation decision making.
A 44-year-old man underwent coronary bypass graft surgery in the setting of severe LV systolic dysfunction related to anabolic steroid use and coronary artery disease. Despite prolonged, postoperative mechanical support, there was no evidence of LV function recovery, and the patient underwent insertion of a Heartware LVAD (HVAD). Six months later, a transthoracic echo on full LVAD support revealed a low normal LV ejection fraction (LVEF), normal LV end-diastolic dimension, and aortic valve opening with each beat. These data prompted a LVAD explantation …