Systemic and pulmonary hemodynamic effects of inhaled high-concentration nitric oxide in patients with coronary artery disease

Abstract

Aim.  To evaluate the acute hemodynamic effects of inhaled nitric oxide (iNO) 200 ppm for prevention of nosocomial pneumonia (NP) in patients with coronary artery disease (CAD) after bypass grafting (CABG), as well as to confirm the beneficial effect of high-concentration iNO on pulmonary circulation and rule out any adverse effects on systemic circulation. Material and methods.  A subanalysis of the randomized, single-blind RECORD study (www.clinicaltrials.gov, № NCT06162455) was conducted. We analyzed 12 patients with CAD and risk factors for NP. Two days after CABG, they underwent the first iNO procedure in a cycle of 200 ppm inhalations for 30 minutes twice daily for 5 days to prevent CAD. NO inhalations were performed using a Tianox-V system (Russia). During iNO, blood pressure, heart rate, and blood oxygen saturation (SpO 2 ) were continuously monitored. Left and right cardiac parameters, systemic and pulmonary hemodynamics were assessed using a Vivid 95 ultrasound diagnostic system (GE HealthCare, USA). Parameters were recorded at baseline and at 10 and 30 minutes of iNO. Statistical analysis was performed using SPSS. Results.  Against the background of iNO, we revealed a decrease in the tricuspid regurgitation velocity (TRV) (p=0,007), right ventricular systolic pressure (RVSP) (p<0,001), an increase acceleration time/ejection time ratio (AT/ET) in the right ventricular (RV) outflow tract (p=0,012), an increase in tricuspid annular plane systolic excursion (TAPSE) (p<0,001), a decrease in inferior vena cava (IVC) diameter and increase in percentage of inspiratory collapse (p=0,045) by the 10 th  minute of iNO. Changes in right heart and pulmonary artery pressure (TRV, RVSP, AT/ET ratio) were recorded by the 10 th  minute of iNO administration and remained unchanged as inhalation continued. Increases in TAPSE and changes in IVC loading parameters became significant by the 30 th  minute. Blood pressure, heart rate, and SpO 2  remained unchanged throughout the inhalation period. Conclusion.  Inhalation of nitric oxide at a concentration of 200 ppm for 30 minutes does not affect systemic hemodynamic parameters, demonstrating its safety profile in CAD patients after CABG. This leads to selective vasodilation of the pulmonary artery and its branches, which revealed a decrease in systolic and mean pressure and an indirect decrease in RV afterload with an improvement in its systolic function. ere detected.