Impact of smoking cessation on cardiovascular outcomes in patients with myocardial infarction with nonobstructive coronary arteries.

Background: : Smoking is a preventable risk factor for incident cardiovascular disease. The impact of smoking status and potential benefits of smoking cessation in a distinct population with myocardial infarction with nonobstructive coronary arteries (MINOCA) remain poorly understood. Methods: : In this prospective single-center cohort study, 1179 patients with MINOCA were classified as non-, ex-, or current smokers based on smoking status at baseline. Current smokers were further categorized as persistent smokers or quitters due to their continued tobacco use or cessation within 1 year after MI. The primary endpoint was major adverse cardiovascular events (MACE), a composite of death, nonfatal MI, stroke, revascularization, and hospitalization for unstable angina or heart failure. Results: : At multivariate Cox analysis, current smoking was independently associated with an increased risk of MACE compared to non-smokers over the median follow-up of 41.7 months [adjusted hazard ratio (aHR) 1.53; 95 % confidence interval (CI): 1.22-1.89, p < 0.001], whereas ex-smokers had a similar risk of MACE to non-smokers. Current smokers with ≥10 pack-years of exposure had a higher risk of MACE, and a near-linear trend was noted between cumulative smoking and MACE risk. Individuals who continued smoking had a significantly higher risk of MACE compared to quitters (aHR 1.70; 95 % CI: 1.17-2.47, p = 0.005). The benefits of smoking cessation remained consistent in subgroup and sensitivity analyses. Smokers who had substantial cigarette reduction or switched to E-cigarettes might also have a lower risk of MACE. Conclusions: : Current smokers had worse outcomes as compared to non-smokers after MINOCA. Smoking cessation was associated with a reduced risk of adverse events, indicating the necessity of sustained smoking cessation in MINOCA population.