Smoking linked to worse prognosis in STEMI patients after PCI

Recent smoking is not associated with infarct size or microvascular obstruction (MVO) but contributes to a worse prognosis after primary percutaneous coronary intervention in ST-segment elevation myocardial infarction (STEMI), a study has shown.

Ten randomized trials of patients with STEMI undergoing primary PCI provided individual patient-data that were pooled in this study. Cardiac magnetic resonance imaging or technetium-99m sestamibi single-photon emission computed tomography was used to assess infarct size at a median of 4 days.

Multivariable analysis was performed to examine the association between smoking, infarct size and the 1-year rates of death or heart failure (HF) hospitalization and reinfarction.

Less than half of 2,564 patients with STEMI were recent smokers (n=1,093; 42.6 percent), and these patients were 10 years younger and had fewer comorbidities than nonsmokers. Smokers and nonsmokers had similar infarct size (adjusted difference, 0.0 percent, 95 percent confidence interval [CI], –3.3 percent to 3.3 percent; p=0.99) and extent of MVO.

Smokers, compared with nonsmokers, showed lower crude 1-year rates of all-cause death (1.0 percent vs 2.9 percent; p<0.001) and death or HF hospitalization (3.3 percent vs 5.1 percent; p=0.009) but similar rates of reinfarction.

Adjustment for age and other risk factors showed similar 1-year risk of death (adjusted hazard ratio [aHR], 0.92, 95 percent CI, 0.46–1.84) between smokers and nonsmokers, but the former had higher risks of death or HF hospitalization (aHR, 1.49, 95 percent CI, 1.09–2.02) and reinfarction (aHR, 1.97, 95 percent CI, 1.17–3.33).

Younger age and fewer cardiovascular risk factors in smokers vs nonsmokers may explain the smoker’s paradox, according to the authors.