Effect of smoking on endothelium-independent vasodilatation.

Overview

BACKGROUND: Smoking induces an impairment of endothelium-dependent vasodilatation. In this study we assessed whether smoking also causes an impairment of endothelium-independent vasodilatation. METHODS: We studied 2 groups of young healthy subjects: 1) 12 medical students (24.5 ± 0.9 years; 6 male) without cardiovascular risk factors (CVRFs), except smoking (≥10 cigarettes/day); 2) 12 matched controls (24.5 ± 1.1 years; 6 male) without any CVRF. Nitrate-mediated dilatation (NMD) of the brachial artery was assessed in response to the random administration of 4 different doses (10, 20, 30 and 40 μg) of sublingual nitroglycerin (NTG). Flow-mediated dilatation (FMD) was also assessed. RESULTS: The increasing doses of NTG determined a progressive increase of NMD in both groups, but the dose-response curve was significantly lower in smokers compared to controls (p < 0.001). FMD was also lower in smokers, compared to controls (6.12 + 0.6 vs. 8.06 + 0.9%, p < 0.001). CONCLUSIONS: Our data show that smoking induces an early impairment of endothelium-independent arterial dilatation.