Vascular Functional and Morphological Alterations in Smokers during Varenicline Therapy.

Background: Varenicline has been reported to achieve high rates of smoking cessation. It remains undetermined whether varenicline therapy improves vascular function in smokers.
Methods: Consecutive Seventy-two smokers (age 57 ± 12 years) who succeeded in complete smoking cessation and 46 normal healthy volunteers (age 24 ± 3 years) with no cardiovascular risk factors were enrolled into this study. Vascular function and structure were assessed by flow-mediated dilation (FMD), nitroglycerin-induced vasodilation, and brachial artery intima-media thickness (baIMT) at baseline and 20 weeks after the initiation of varenicline therapy in smokers. FMD and baIMT were measured simultaneously using a semi-automatic vessel wall-tracking software program. 75 μg dose of a nitroglycerin tablet were sublingually administered for the nitroglycerin-induced vasodilation measurement.
Results: Exhaled-carbon monoxide concentration decreased significantly (20.0 ± 11.1 ppm at baseline vs 1.9 ± 1.5 ppm after 20 weeks, p < 0.001). FMD was significantly improved after 20 weeks (4.09% ± 1.83% at baseline vs 4.77% ± 2.33% after 20 weeks, p = 0.010), whereas nitroglycerin-induced vasodilation and baIMT were not significantly changed.
Conclusions: Smoking cessation with varenicline therapy significantly increased FMD without significant changes of nitroglycerin-induced vasodilation or baIMT from baseline to 20 weeks. It appears to improve vascular function in smokers, which depends on endothelial function rather than on vascular smooth muscle function or changes in vascular structure.