Clinical characteristics, aetiological factors and long-term prognosis of myocardial infarction with an absolutely normal coronary angiogram - A 3-year follow-up study of 91 patients

Objectives The purpose of this study was to evaluate the clinical outcome o f a large cohort of patients who suffered an acute myocardial infarction wi th absolutely normal epicardial coronary arteries at the post-myocardial in farction coronary angiogram. The aetiological and prognostic factors in thi s population were also analysed. Background Few data exist concerning the outcome, and aetiological and prog nostic factors, of patients with myocardial infarction and angiographically absolutely normal coronary arteries. Methods Ninety-one patients (34 females/57 males; mean age 50 +/- 13 years, range 24-78 years) admitted with an acute myocardial infarction had absolu tely normal coronary arteries at the angiogram performed 6.2 +/-4 days (ran ge 1-15 days) after the myocardial infarction, defined by smooth contours a nd no focal reduction (NC). Of the 91 NC patients, 71 were evaluated prospe ctively, alongside a systematic search of all aetiological factors reported in the literature. The NC patients were matched for age, sex, and the same period of myocardial infarction onset with a group of 91 patients with cor onary artery stenosis (>50% diameter stenosis) at the angiogram performed 7 .3 +/-4 days (range 1-15 days) after the myocardial infarction (SC). Results The percent of smokers was similar between the two groups; higher p revalence rates of coronary heart disease family history, obesity, hyperten sion, hypercholesterolaemia and diabetes mellitus were found in SC (P=0.043 to 0.0001). In NC, coronary spasm was found in 15.5%, congenital coagulati on disorders in 12.8%, collagen tissue disorders in 2.2%, embolization in 2 .2%, and oral contraceptive use in 1.1%. Left ventricular ejection fraction at hospital discharge was higher in NC (60%+/- 13%) than in SC (55%+/- 13% , P=0.04). The mean follow-up was 35 months (range 1-100 months). Kaplan-Me ier event-free survival, with the combined end-point defined as death, rein farction, heart failure and stroke was 75% in NC vs 50% in SC (P<0.0001). S urvival rate was 94.5% in NC compared to 92% in SC (ns). Univariate predict ors of events in NC were left ventricular ejection fraction (P=0.03), age ( P=0.02), diabetes (P=0.01), and smoking (P=0.03). Using Cox multivariate an alysis, independent predictors of longterm outcome in NC patients were left ventricular ejection fraction (P=0.003) and diabetes (P=0.004). Conclusion Aetiological factors, predominantly coronary spasm and inherited coagulation disorder, can be detected in only one third of the patients wi th myocardial infarction and absolutely normal coronary angiograms despite a systematic search in a prospective population. Mortality rates are simila r but morbidity is lower in myocardial infarction patients with absolutely normal coronary angiography compared with those with coronary artery stenos is. The only two independent factors predictive of poor outcome in myocardi al infarction patients with normal coronary arteries are left ventricular f unction and diabetes. (Ear Heart J 2001; 22: 1459-1465, doi:10.1053/euhj.20 00.2553) (C) 2001 The European Society of Cardiology.