Effects of smoking cessation on endothelial function assessed by flow-mediated dilation and reactive hyperemia peripheral artery tonometry

Abstract

Abstract Background Smoking predisposes individuals to endothelial dysfunction. Both flow-mediated dilation (FMD) and reactive hyperemia peripheral artery tonometry (RH-PAT) are used to assess endothelial function. However, there are differences in the physiology of vascular beds being tested and in the response of conduit and resistive vessels to RH. Therefore, whether smoking cessation demonstrates comparable effects on endothelial function evaluated by FMD and by RH-PAT remains unclear. Purpose We aimed to evaluate the effects of smoking cessation on endothelial function evaluated simultaneously by FMD and RH-PAT. Methods Thirty-eight consecutive current smokers (mean±standard deviation; age, 65±10 years) who visited our smoking cessation outpatient department and succeeded in smoking cessation with varenicline were enrolled. Clinical variables, FMD, and natural logarithmic transformation of the reactive hyperemia index (Ln-RHI) were examined before and 20 weeks after treatment initiation. Fifteen current smokers who failed in smoking cessation were enrolled as age- and sex-matched controls. The Spearman's rank correlation coefficient and intraclass correlation coefficient (ICC) for a two-way mixed effects model were performed to assess the agreement of changes in FMD and Ln-RHI. Multivariate logistic regression analysis was performed to examine the associations between the presence of increase in FMD or Ln-RHI and clinical variables. Results FMD significantly improved after smoking cessation (3.42%±1.96% to 4.45%±2.28%; p=0.019), whereas Ln-RHI did not (0.53±0.25 to 0.59±0.21; p=0.223). The Spearman's rank correlation coefficient between changes in FMD and Ln-RHI was −0.013, and the ICC was −0.002 (p=0.506). In the multivariate logistic regression analysis, an increase in FMD or Ln-RHI was predicted based on the baseline FMD (odds ratio = 0.54, p=0.013) or Ln-RHI (odds ratio = 0.36, p=0.012), respectively, after adjusting for age and sex. Conclusions There was significant improvement in the endothelial function assessed by FMD, but not by Ln-RHI, after smoking cessation. In addition, there was disagreement between changes in FMD and those in Ln-RHI. Smoking cessation may have varying effects on the endothelial function of the conduit and digital vessels. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-aid for scientific research from the ministry of education, science and culture of Japan