Effects of Nitric Oxide on Hemodynamics After Transcatheter Mitral Valve Repair Complicated by Pulmonary Hypertension　― A Study Protocol ―

Abstract

Background: Elevated pulmonary arterial pressure (PAP) is associated with poor prognosis in patients with functional mitral regurgitation (MR) undergoing transcatheter mitral valve repair (TMVr). Nitric oxide (NO) inhalation therapy reduces PAP and pulmonary vascular resistance (PVR) after open-heart surgery, but its efficacy in patients with pulmonary hypertension (PH) undergoing catheter intervention remains unclear.

Methods and Results: This open-label, interventional, randomized controlled trial will investigate the efficacy of NO inhalation therapy after TMVr for MR complicated by PH. A total of 40 patients aged ≥18 years diagnosed with PH (mean PAP >20 mmHg) during preoperative right heart catheterization and scheduled for TMVr for MR are included in this study. Patients receiving pulmonary vasodilators, with NO contraindications, and with unstable conditions requiring intravenous catecholamines or mechanical circulatory support devices are excluded. Eligible patients are randomly allocated to the NO inhalation or control group in a 1 : 1 ratio. NO (20 ppm) is administered post-TMVr (D0) until the day after TMVr (D1). The control group is administered oxygen as necessary. The primary endpoint is the change in PVR (baseline to D1). The secondary endpoints include changes in cardiac index and mean PAP (baseline to D1), changes in PVR immediately before NO administration post-TMVr to D1, and postoperative complication rates.

Conclusions: This study will assess the efficacy of NO inhalation in patients with PH undergoing TMVr for MR.