A Phase 2, Randomized, Clinical Trial of Inhaled Nitric Oxide for Acute Severe Right Heart Failure With Pulmonary Hypertension (PHiNO Study).

BACKGROUND

Acute right heart failure (RHF) is life threatening in patients with pulmonary hypertension (PH). This study investigated the efficacy and safety of inhaled nitric oxide (iNO; INOflo®for inhalation 800 ppm), a rapid pulmonary vasodilator, in patients with acute severe RHF due to PH.

METHODS AND

RESULTS

In this Phase 2 randomized controlled trial, 30 patients with acute severe RHF due to PH (pulmonary arterial hypertension or chronic thromboembolic PH) were randomized 1 : 1 to either an iNO or control group (which did not receive iNO). The primary endpoint was the change in pulmonary vascular resistance (PVR) from baseline to 30 min after either iNO initiation or patient registration and assignment (control group), which differed significantly between the iNO and control groups (mean [±SD] -2.41±2.47 vs. 0.8±1.03 Wood units, respectively; between group difference -3.21 [95% confidence interval -4.633, -1.785] Wood units). Serum B-type natriuretic peptide (BNP) levels and inferior vena cava diameter (secondary endpoints) decreased significantly in the iNO group over the 7-day study period. No serious adverse events, including methemoglobinemia, were observed.

CONCLUSIONS

iNO significantly reduced PVR in patients with acute severe RHF due to PH, without serious adverse events. Serum BNP levels and inferior vena cava diameter improved in the iNO group. These findings suggest that iNO is a promising acute treatment option for RHF due to PH.