Quitting smoking has varied effects on endothelial function

Smoking cessation appears to have varying effects on endothelial function, eliciting different changes in flow-mediated dilation (FMD) and the reactive hyperemia index (RHI), a recent study has found.

The study included 58 successful quitters (mean age, 64±11 years; 31.0 percent female) who underwent FMD and RH-peripheral artery tonometry. For data analysis, RHI was expressed as the natural logarithm (ln-RHI), and multivariate logistic regression analysis was used to detect correlates of increases in FMD and ln-RHI. A parallel group of 21 continuing smokers was also included for comparison.

FMD significantly increased in those who had successfully quit, suggesting improved endothelial functions (3.80±2.24 percent vs 4.60±2.55 percent; p=0.013). However, no such differences were reported for ln-RHI (0.59±0.28 vs 0.66±0.22; p=0.092).

Spearman’s rank correlation analysis revealed low agreement between the change values of FMD and ln-RHI (coefficient, –0.004), which was confirmed by a intraclass correlation coefficient value <0.001 (p=0.499).

In turn, predictive valuables for either measure of endothelial function also differed. Increases in FMD, for example, were significantly associated with the Brinkman index (p=0.043), baseline FM (p=0.03), and changes in systolic blood pressure (SBP; p=0.04).

On the other hand, an increase in ln-RHI was predicted by baseline ln-RHI (p=0.001), changes in SBP (p=0.047), and baseline body mass index (p=0.032).

“To the best of our knowledge, this is the first study to assess endothelial function by FMD and RH-PAT simultaneously before and after smoking cessation and demonstrate different serial changes in endothelial function between FMD and RH-PAT assessments,” the researchers said.

They added that the different correlated factors “may be able to predict the varying effects of smoking cessation on the endothelial function of the conduit and digital vessels.”