3D echocardiographic optimization of residual native myocardial function in patients with left ventricular assist devices

摘要

Preservation of native left ventricular (LV) function in patients supported with left ventricular assist device (LVAD) may be beneficial to attain optimal hemodynamics and theoretically enhance potential recovery. Currently, LVAD speed optimization is based on hemodynamic parameters, without considering residual native LV function. We hypothesized that, alternatively, LV rotational mechanics can be quantified by 3D echocardiography (3DE), and may help preserve native LV function while optimizing LVAD speed. We sought to: (1) test the feasibility of quantifying the effects of LVAD implantation on LV rotational mechanics, and (2) determine whether conventional speed optimization maximally preserves native LV function. We studied 55 patients with LVADs, who underwent transthoracic 3DE imaging (Philips) and quantitative analysis of LV twist (TomTec). Thirty patients were studied before and after LVAD implantation. The remaining 25 patients were studied during hemodynamics ramp studies. The pump speed at which LV twist was maximal was compared with the hemodynamics based optimal speed. LV twist decreased following LVAD implantation from 4.2±2.7 to 2.3±1.9° (p<;0.01), reflecting the constricting effects on native function. During the lower speeds of the ramp studies, no significant changes were noted in LV twist, which peaked at a higher pump speed. In 11/25 (44%) patients, the conventional hemodynamic+2DE methodology and 3DE assessment of maximal residual function did not indicate the same optimal conditions, suggesting that at a higher pump speed would have better preserved native function. Quantitative 3DE analysis of LV rotational mechanics provides information, which together with hemodynamics may help select optimal pump speed, while better preserving native LV function.