Effect of Smoking Cessation on Left Ventricular Ejection Fraction after Acute ST Elevation Myocardial Infarction.

Background: Acute Myocardial Infarction (AMI) is the leading cause of global mortality. Moreover, Left Ventricular Ejection Fraction (LVEF) is the most important predictor of post-AMI mortality. Thus, the present study aimed to investigate the relationship between smoking cessation and LVEF following one year from the STEMI.

Method: The present study was a part of the Kermanshah STEMI Registry and included 825 smokers admitted to Imam Ali Hospital, Kermanshah, Iran, with AMI during a 2-year study period. Data collection was performed using the standardized case report form by the European Observational Registry Program (EORP). Moreover, multiple logistic regression was used to compare LVEF between the patients who had quit smoking post-AMI and those who were still smokers after one year. Also, one-to-one Propensity Score Matching (PSM) was used to reduce the assessment error and selection bias, increase the result accuracy, and minimize the effects of confounders on the LVEF-smoking relationship.

Results: Following one year after AMI, 219 (26.55%) patients had quit smoking, while 606 (73.45%) still smoked. Using the PSM, a total of 168 ex-smokers were matched to 168 current smokers. Moreover, it was shown that LVEF was higher in current smokers compared to ex-smokers. However, the difference was not significant. Also, multiple logistic regression showed that the Odds Ratio (OR) of LVEF reduction was insignificantly higher in ex-smokers (OR=1.13; 95% CI: 0.98-1.29) compared to current smokers. Multivariate regression analysis found similar results even after the application of PSM (OR = 1.02; 95% CI: 0.82-1.22).

Conclusions: Given the low rate of smoking cessation after MI, physicians are recommended to ask about the smoking status of MI patients at each office visit or re-admission and strongly recommend quitting smoking.