Smoking is a major and reversible risk factor for coronary artery disease. The present work aims to define the risk factors, angiographic and clinical characteristics and evolution of acute coronary syndromes in smokers.
Methods: We studied 521 consecutive patients with acute coronary syndrome admitted to the intensive care unit who underwent catheterization. We assessed the population in terms of risk factors, pathology (unstable angina or acute myocardial infarction), coronary morphology, left ventricular function, the need for intervention, evolution and complications over a one-year period. The characteristics of smokers were then compared with those of non-smokers.
Results: Of the 521 patients with acute coronary syndrome (391 men), 182 (35 %) were smokers. The smokers were younger than the non-smokers (56.3+/-9.5 versus 66.4 +/- 7.8; p < 0.001), were more frequently male (91 versus 66%; p < 0.001), and presented more risk factors (43% with 3 or more risk factors versus 17% in non-smokers; p < 0.001), more obesity (11 versus 5%; p < 0.01), and less diabetes (19 versus 37%; p < 0.001). Smokers presented greater prevalence of acute myocardial infarction (57 versus 40%; p < 0.001) and less unstable angina. Coronary morphology was not significantly different in smokers compared to non- smokers and left ventricular function after the aculte coronary syndrome was similar in both groups. Smokers less frequently underwent surgery during hospitalization (22% versus 35%; p < 0.01) but needed angioplasty as often as non-smokers (48% versus 16%; NS). Smokers presented more frequent complications (angina, heart failure, re-infarction or CABG) than non-smokers (26% versus 17%; p < 0.01), during the first year of follow-up. One-year mortality was similar in both groups. The results were not significantly different when adjusted for gender.
Conclusions: On average, acute coronary syndrome occurred 10 years earlier in smokers than in non-smokers. The former generally presented more risk factors, lower prevalence of diabetes and higher of obesity, more myocardial infarctions and less unstable angina. After the acute coronary syndrome, at one year, smokers presented more complications than non-smokers but had similar mortality.