Changes in the functional status measures of heart failure patients with mechanical assist devices

Continuous-flow left ventricular assist devices (cfLVADs) have been proven safe and effective for bridge-to-transplant and destination therapy (DT) in patients with advanced heart failure. However, the fixed pump speed of these devices may lack response to activity and oxygen demand, thereby limiting exercise tolerance. The objective of this observational study was to describe exercise capacity as measured by peak oxygen consumption (peak VO2) that may be expected during support with a cfLVAD. Peak VO2 was measured in patients (mean age: 58.3 ± 11.7 years; 66.7% ischemic and 33.3% DT) before cfLVAD support (11.2 ± 3.0 ml/kg/min, n = 25), between 3 and 6 months (12.7 ± 3.5 ml/kg/min, n = 31), at 1 year (10.7 ± 2.6 ml/kg/min, n = 16), and longer than 1 year (11.2 ± 1.7 ml/kg/min, n = 10). There was no statistical improvement in peak VO2 at any time point after implantation. In addition, ventilatory efficiency remained poor after LVAD implantation at all time points. Although studies have shown an increase in survival and patient's quality of life, exercise capacity as measured by cardiopulmonary exercise testing remains low during cfLVAD support.