Effects of inhaled nitric oxide during mechanical circulatory support: a prospective pilot study.

Among patients with cardiogenic shock receiving Impella-based mechanical circulatory support, pulmonary vascular load and right ventricular dysfunction may affect left ventricular preload and device flow. Prospective data on the acute hemodynamic effects of inhaled nitric oxide (iNO) in this setting are limited. We evaluated short-term hemodynamic changes after iNO initiation in patients receiving Impella or Impella combined with veno-arterial extracorporeal membrane oxygenation (ECPELLA) support. We conducted a prospective single-center pilot study of adult patients receiving Impella or ECPELLA support who were treated with iNO. iNO was initiated at 20 ppm after initial circulatory resuscitation once pulmonary artery pulse pressure could be reliably assessed. Hemodynamic variables were recorded immediately before iNO initiation (T0) and 30 min (T1) and 24 h (T2) after initiation. The primary endpoint was the change in mean pulmonary artery pressure (mPAP) from T0 to T1. We enrolled 11 patients, and 10 were analyzed. mPAP decreased from 19.0 (14.8-20.3) mmHg at T0 to 16.5 (12.8-19.3) mmHg at T1 (P = 0.004). The T0-T2 difference was not significant. Lactate levels decreased, but this temporal change could not be attributed directly to iNO without a control group. Methemoglobin levels increased slightly at T2 without clinical methemoglobinemia. iNO was temporally associated with an early reduction in mPAP in patients receiving Impella-based support, without clear improvement in systemic hemodynamic indices. These hypothesis-generating findings require confirmation in larger controlled studies.