Acute impact of left ventricular unloading by left ventricular assist device on the right ventricle geometry and function: Effect of nitric oxide inhalation

Objective: Left ventricular assist device (LVAD) implantation is an established option for treatment of patients with end-stage heart failure, but outcome may be worsened by right ventricular failure. The aim of this study was to evaluate the acute effect of LVAD on right ventricular geometry and function and the pulmonary circulation. The effect of inhaled nitric oxide (iNO) was assessed. Methods: We evaluated pre- and postoperatively obtained transesophageal echocardiography images and hemodynamics of patients participating in a randomized trial on the effect of inhaled nitric oxide during LVAD implantation. Twenty-four patients were randomized to the iNO group and 23 to the placebo group. Results: After LVAD implantation marked decreases in pulmonary capillary wedge pressure (P < .01) and mean pulmonary artery pressure (P < .01) were observed in both groups. Pulmonary vascular resistance decreased only in the iNO group (311 +/- 35 to 225 +/- 17, P < .01). Transesophageal echocardiography measurements show significant improvement of right ventricular geometry (right ventricular end-diastolic diameter: 50 +/- 2 to 45 +/- 2, P < .01 and 48 +/- 2 to 44 +/- 2 mm, P < .05 in iNO and placebo groups) and function (right ventricular fractional area change: 24% +/- 2% to 31% +/- 2%, P < .05 and 23% +/- 2% to 29% +/- 2%, P < .05 in iNO and placebo groups) without any difference between the iNO and placebo groups. The overall incidence of postoperative right ventricular failure was 4 of 47 (8.5%). Conclusions: LVAD implantation markedly improved right ventricular geometry and function in most of the patients, probably by resolving left ventricular congestion and thus reducing right ventricular afterload. Beneficial effects of iNO may have been masked by more pronounced consequences of left ventricular unloading on right ventricular function. (J Thorac Cardiovasc Surg 2011;141:1009-14)