Abstract 10041: Cardiopulmonary Performance Among Heart Failure Patients Before and After Left Ventricular Assist Device Implantation

Abstract

Introduction: Continuous-flow left ventricular assist devices (CF-LVAD) improve survival and subjective assessments of health-related quality-of-life (HRqOL) when implanted into patients with advanced heart failure with reduced ejection fraction (HFrEF). However, functional capacity remains severely reduced. Hypothesis: LVAD flow during exercise contributes minimally to overall functional capacity. Exercise tolerance depends on intrinsic factors such as cardiac output (Qc) and arteriovenous oxygen difference (avo2 diff ). Methods: Ten patients (9 male, 60±10 years), underwent three invasive cardiopulmonary exercise tests on upright cycle ergometry. Visits were arranged 1) before (median, IQR: 0.3, 0.1-0.05 months) implantation, 2) after (4.2, 3.1-5.3 months) implantation with CF-LVAD speed held constant, and 3) with increases in pump speed during exercise (2.3, 1.9-3.0 months) after Visit 2. Submaximal functional capacity was measured by six-minute hall walk (6MHW). Fick Qc was measured via pulmonary artery catheter and gas exchange parameters determined by indirect calorimetry. Subjective assessments of HRqOL were obtained prior to and following implantation. Results: Following implantation, HRqOL and 6MHW improved. The avo2 diff and Qc predicted Watts achieved during exercise testing pre-implantation. The avo2diff, but not LVAD flow or Qc, predicted Watts achieved on multivariable analysis with both fixed and variable pumps speeds ( Table 1 ). Conclusions: Submaximal exercise performance and subjective HFrEF severity improved post implantation. The primary determinant of workload achieved during exercise testing, regardless of whether participants exercised at a fixed pump speed or with increases in pump speed, was the (A-V)O2 difference. LVAD flow contributes minimally to functional capacity.