[Smoking paradox in acute coronary syndrome without ST-segment elevation]

Abstract

Background and objective: Although smoking habit is a well-known cardiovascular risk factor, it has been described that smokers admitted because of myocardial infarction have better prognosis than non smoker patients, which is known as "the smoking paradox". The purpose of our work is to investigate whether this phenomenon occurs among patients admitted because of acute coronary syndrome without ST-segment elevation (NSTACS), and which factors help to explain it.

Patients and methods: We analysed 563 consecutive patients admitted because of NSTACS on the Coronary Unit of our hospital from January 2005 to December 2006. We analysed clinic and angiographic characteristics and their relationship with in-hospital complications and prognosis.

Results: 155 Patients were smokers (27.53%). Smoker patients were younger, more often male, had less risk factors, and more often had a Killip I class at admission (91.6% vs. 79.3%). They had less commonly the combined endpoint of death, reinfarction or Killip Class IV (6.5 vs 13.6%, odds ratio 0.439, confidence interval 0.218 a 0.885, P=.018). This relationship was lost after adjusting to other significant clinical and angiographic data by logistic regression.

Conclusions: Our study confirms the "smoking paradox" amongst NSTACS patients, which is explained by the lower prevalence of previous myocardial infarction, diabetes or multivessel disease. It is essential to recommend quitting the smoking habit.