Non-invasive evaluation of endothelial function in healthy Indian participants using tonometry

Abstract

Background: Vascular endothelium releases number of biological active mediators, including nitric oxide (NO) that regulates vessel tone. Endothelial dysfunction is independent risk factor for cardiovascular disease. The study was done to assess endothelial function by augmentation index (AIx) calculated from derived aortic wave forms using radial pulse wave analysis (PWA) with provocative pharmacological testing, measured in response to endothelium independent, direct stimulus with nitrovasodilator nitroglycerine (NTG) and endothelium dependent activation of L-arginine-NO-pathway by salbutomol. Methods: Eighteen healthy subjects participated in the study. Radial artery wave forms were recorded with a high-fidelity tonometer (Sphygmocor, AtCor medicals, Australia). Recordings were taken at baseline and after 3, 5, 10, 15 and 20 minutes of NTG (0.5 mg) sublingual administration, and at baseline and after 5, 10, 15 and 20 minutes of salbutomol (400 µg) inhalation. Results: Mean age was 25±2.4 years and body mass index 24±2.5 kg/m 2 of study subjects. Salbutomol and NTG significantly reduced AIx at all-time points (salbutomol: baseline 7.6%, 5 minutes -3.6%, 10 minutes -5.8%, 15 minutes -7.8% and 20 minutes -3.6%, p ≤0.05 and NTG baseline 8.4%, 3 minutes -3.2%, 5 minutes -7.7%, 10 minutes -9.7%, 15 minutes -11.2% and 20 minutes -8.6%, p ≤0.001). The effect of provocative pharmacological testing on heart rate, aortic and radial pressures, mean arterial pressure and pulse pressure was not altered (p≥0.05). Conclusions: This method of assessing endothelial function, which appears before onset of clinical signs and symptoms and is a simple, convenient, quick method.