Nitric oxide inhalation in the treatment of right ventricular dysfunction following left ventricular assist device implantation

Background Following left ventricular assist device (LVAD) implantation in end-stage heart failure, the management of right ventricular dysfunction presents a therapeutic problem unresolved by conventional drug therapy (catecholamines, nitrates, and prostacyclin). This study was performed to investigate the effects of supplemental inhalation of nitric oxide (NO), a selective pulmonary vasodilator, postoperatively and prospectively. Methods and Results Intraindividual dose titration of NO was performed (0 to 40 ppm) according to a standardized protocol. Thereafter treatment was continued with the individually most effective dose of NO (25 to 40 ppm). In 8 consecutive male patients presenting with right ventricular dysfunction postoperatively, a significant dose-dependent improvement in hemodynamic function was observed: pulmonary vascular resistance decreased from 336 +/- 110 to 210 +/- 59 dynes.s.cm(-5) (P < .0001), cardiac index rose from 2.0 +/- 0.4 to 2.7 +/- 0.4 L.min(-1).m(-2) (P < .003) at 40 ppm; doses of > 20 ppm were effective in increasing cardiac index (P < .05). With continuous NO inhalation up to 48 hours, pulmonary vascular resistance decreased further to 155 +/- 33 dynes.s.cm(-5) (P < .0001) as the cardiac index increased to 3.3 +/- 0.6 L.min(-1).m(-2) (P < .003). Pulmonary artery pressure decreased (P < .0001) as did systemic vascular resistance with hemodynamic improvement (P < .01). Central venous pressure and mean arterial pressure remained unchanged. Right ventricular ejection fraction at transesophageal echocardiography increased from 24 +/- 7% to 44 +/- 7% (P < .01) at the end of the study, and right ventricular end-diastolic volume decreased (P < .05). Weaning from NO therapy was successful at 2 to 8 days, and all patients were extubated. Right ventricular function remained stable thereafter. Conclusions In the treatment of right ventricular dysfunction following LVAD implantation, inhalation of NO markedly decreased right ventricular afterload by its selective vasodilating effects on the pulmonary circulation without producing systemic hypotension; this merits further evaluation.