Peak Oxygen Consumption and Six-Minute Walk Distance in Patients with an HVAD Left Ventricular Assist Device at Discharge from Cardiac Rehabilitation

Purpose: Physical capacity is an important precondition for participation and integration in everyday life following LVAD implantation. At discharge from a cardiac rehabilitation (CR) the patient should once more become capable to manage the necessary tasks autonomously. Measurement of peak oxygen consumption and six-minute walk distance (6MWD) is well established in order to evaluate the individual situation.Methods: Retrospective analysis of data from a German cardiac rehabilitation center between 2013 and 2015: The results from 47 HVAD patients (57.7 ± 9.6 yrs, BMI 25.5 ± 5.3, 87 % male, 55 % ICM) were included. During CR a cardiopulmonary exercise test (bicycle ergometer; ramp protocol; 10W/min) and two six-minute walk tests were performed. Statistical analysis was performed using IBM SPSS Statistics Version 23.Results: At discharge from CR (52 ± 17 days after implantation), the mean peak work load achieved was 63 ± 19 W (40 % of predicted values) and the peak oxygen consumption averaged 10.8 ± 3.0 ml/kg/min (38 % of predicted values). 6MWD improved significantly during CR (325 ± 107 m to 416 ±73 m; p < 0.01) and reached 70 % of predicted values (resp. 94 % of Lower Limit of Normal). Correlations between 6MWD and peak work load (r = 0.626, p < 0.01) as well as peak oxygen consumption (r = 0.422, p < 0.01) were evidenced.Conclusion: The results show that peak oxygen consumption and peak work load remain markedly limited shortly after LVAD implantation. In contrast 6MWD reaches very acceptable levels. This may indicate that submaximal loads could be significantly better mastered than peak loads. Easy daily activities can be accomplished by the patients so that a discharge from CR is possible. However, physically demanding tasks are not feasible in LVAD patients, at least shortly after implantation. For further evaluation long-term studies are needed.