Non-invasive assessment of myocardial recovery on chronic left ventricular assist device: results associated with successful device removal.

BACKGROUND

Myocardial recovery may occur in patients with heart failure who are receiving left ventricular assist-device support, but identification of candidates for device removal remains challenging. We hypothesized that on-line quantitative echocardiography during trials of decreased device support alone or in combination with exercise cardiopulmonary testing can assess cardiac recovery to predict successful device removal.

METHODS

We studied 18 patients with severe heart failure, aged 45 +/- 19 years, who received 234 +/- 169 days of assist-device support as a bridge to transplantation. We used echocardiographic automated border detection from mid-ventricular short-axis images and non-invasive arterial pressure to measure beat-to-beat responses in 2 to 5 minute trials of decreased device flow. We also assessed maximal oxygen consumption in 14 patients who could exercise.

RESULTS

Six patients experienced myocardial recovery and underwent successful device removal; 12 remained device dependent. With transient, low assist-device flow, patients with device removal had increased echocardiographic stroke area of 27% +/- 36% vs -24% +/- 12% (p < 0.05) and fractional area change of 51% +/- 13% vs 23% +/- 11% (p < 0.05) in the patients who were device dependent. Estimates of pre-load-adjusted maximal power, a relatively load-independent index, were 6.7 +/- 2.1 mW/cm(4) in patients with successful device removal vs 1.2 +/- 1.2 mW/cm(4) in patients who were device dependent (p < 0.005). Maximal oxygen consumption was 17.2 +/- 1.4 ml/kg/min in patients with myocardial recovery vs 13.1 +/- 1.9 ml/kg/min in patients who were device dependent (p < 0.005) and correlated with pre-load-adjusted maximal power (r = 0.89, p < 0.001). Maximal oxygen consumption >16 ml/kg/min, increased stroke area, >40% increase in fractional area change, or pre-load-adjusted maximal power >4.0 mW/cm(4) with low device flow were associated with successful device removal (p < 0.05).

CONCLUSIONS

On-line quantitative echocardiography alone or combined with exercise cardiopulmonary testing can assess myocardial recovery of patients receiving left ventricular assist-device support and has the potential to identify patients who are clinical candidates for device removal.