BARCELONA — North Americans and Europeans have been presenting with milder acute MIs for the last 2 decades—and a new Swedish study suggests the declining popularity of smoking may be a factor.
The study, which involved 121,032 consecutive admissions for acute MI to Swedish coronary care units in 1996–2004, showed that smoking was an independent predictor of presentation with a more extensive ST-elevation MI (STEMI) rather than a non-ST-elevation MI (NSTEMI), Dr. Lena Bjorck reported at the joint congress of the European Society of Cardiology and the World Heart Federation.
This relationship makes theoretical sense. Smoking is known to promote coagulation and interfere with thrombolysis. Since thrombosis plays a key role in MI, smoking might be expected to result in increased likelihood of a larger STEMI when MI occurs, explained Dr. Bjorck of Sahlgrenska University Hospital, Goteborg, Sweden.
In all, 35% of acute MI patients in this large consecutive series gleaned from the Register of Information and Knowledge about Swedish Heart Intensive Care Admissions presented with STEMI; 27% of STEMI patients were current smokers, vs. just 19% in the NSTEMI group.
The trend was strongest in patients under age 65, in whom 44% of men and 54% of women who presented with STEMI were current smokers, compared with 34% of men and 37% of women with NSTEMI.
Current smoking independently predicted STEMI in MI patients. Among current smokers, men younger than 65 years old who presented with MI were 40% more likely than nonsmokers to have STEMI; women were 90% more likely. Dr. Bjorck noted that besides smoking, improved medical interventions and diagnosis probably also contribute to milder MIs.