Effects of inhaled nitric oxide on endothelial function in patients with ischemic stroke

Abstract

BACKGROUND: A crucial pathogenetic link in the development of stroke is the deterioration of endothelial function, which is a pathological condition characterized by an imbalance between endothelium-dependent relaxing and constricting factors. An example of an endothelium-dependent relaxing factor is nitric oxide, a substance synthesized by the body’s cells that has a vasodilating, antithrombogenic, anti-inflammatory, and antiproliferative effect. Studies have shown the neuroprotective function of inhaled nitric oxide after ischemia; however, determining the minimum effective dose of inhaled nitric oxide in patients who have suffered an acute cerebrovascular accident remains challenging. AIM: To analyze the protective effect of exogenous nitric oxide using the TIANOX device on the vascular endothelium in patients who have had an ischemic stroke in the early and late recovery period during medical rehabilitation. MATERIALS AND METHODS: The study involved 21 patients (10 people in the main group, 56.9±8.9 years old, 11 people in the control group, 57.2±8.8 years old) in the early or late recovery period after an ischemic stroke. Patients in the main group underwent an individual medical rehabilitation program and a course of 8–10 inhalations of a gas mixture with nitric oxide at 20 ppm for 20 minutes. Those in the control group underwent an individual rehabilitation course without nitric oxide therapy. Flow-dependent vasodilation of the brachial artery was evaluated to assess endothelial function. RESULTS: In the main group, a statistically insignificant (p 0.05) increase was found in the diameter of the brachial artery (3.68±0.64 mm), whereas in the control group, this indicator at rest during repeated diagnostics was less than the initial one (3.09±0.87 mm). During repeated diagnostics, the average endothelial shear velocity in patients of the control group increased from 141.53±52.62 to 159.3±82 versus from 143.17±43.53 to 143.48±46.37 in the main group; however, the results were not statistically significant (p=0.753). CONCLUSION: The increase in the diameter of the brachial artery during flow-dependent vasodilation in patients in the main group may indicate a prosthetic effect of the exogenous form of nitric oxide when using the Tianox device on the vascular endothelium, owing to the possibility of depositing nitric oxide in the body. To confirm the obtained data, a larger sample size of patients is critical in order to further divide the groups of patients into early and late recovery periods after ischemic stroke.