["Smoker's paradox" in patients with acute myocardial infarction receiving primary coronary intervention].
OBJECTIVE
Smokers with acute myocardial infarction have lower mortality rates than non-smokers despite increased risk for coronary artery disease. This study assessed the effects of smoking on complications and outcomes after acute myocardial infarction, and investigated the relationship between the clinical factors and the paradoxical effects of smoking in patients receiving primary coronary intervention.


METHODS
Subjects were 367 consecutive patients with acute myocardial infarction who were admitted within 24 hr of onset and underwent successful coronary intervention, 165 (45%) of whom were smokers.


RESULTS
The smoking group contained significantly more male patients, and the smoking group was significantly younger than the non-smoking group (p < 0.0001). The value of acute phase brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) were significantly lower (BNP: 250 +/- 366 vs 448 +/- 513pg/ml, p = 0.0002; ANP: 48 +/- 77 vs 74 +/- 82pg/ml, p = 0.005) in the smoking group. Peak creatine kinase time from onset was significantly earlier (12.9 +/- 9.3 vs 16.1 +/- 10.0 hr, p = 0.049) in the smoking group. Left ventricular ejection fraction in the chronic phase was significantly better in the smoking group (58 +/- 13% vs 52 +/- 14%, p = 0.03). The early ST-segment resolution rate was higher in the smoking group (81% vs 67%, p = 0.003), and there were significantly fewer patients with heart failure in the smoking group than in the non-smoking group (28% vs 41%, p = 0.01). The cardiac mortality rate during 6 months was significantly lower in the smoking group (3% vs 9%, p = 0.01). The beneficial effects of smoking on the prognosis were related with the differences in sex and age of the study group.


CONCLUSIONS
The reason why smokers with acute myocardial infarction have lower mortality rates than non-smokers, the "smoker's paradox", may be related to less damage to the microvascular function after primary coronary intervention, with lower BNP and better left ventricular ejection fraction.
Katayama
Toshiro
T
Department of Cardiology, Kouseikai Hospital, Nagasaki. snowman-kt@syd.odn.ne.jp
Iwasaki
Yoshihiro
Y
Yamamoto
Tadashi
T
Yoshioka
Masato
M
Nakashima
Hiroshi
H
Suzuki
Shin
S
Honda
Yukiharu
Y
Yano
Katsusuke
K
D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D009320:Atrial Natriuretic Factor / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D020097:Natriuretic Peptide, Brain / Q000097:blood; D011379:Prognosis; D012907:Smoking; D013318:Stroke Volume; D016896:Treatment Outcome
D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor