Objective: Rates of coronary angiography (CA) after myocardial infarction (MI) vary widely between institutions. Furthermore, the indications for CA are often in conflict with recognized guidelines. The present study sought to determine the characteristics and the one-year mortality in patients with MI, regardless of age and hospital facilities, according to the use of CA after MI.
Methods and results: Data were prospectively collected in all patients with MI admitted to all hospitals in three departments in the Rhône-Alpes region. Among 2493 patients, 1117 (45%) underwent CA. In multivariate analysis, CA rate was lower with increasing age, female sex, in patients with comorbidity or heart failure. CA was performed in 49% of patients admitted to hospitals with on-site CA vs. 32% in hospitals without on-site CA (OR: 3.54, after adjustment for patients' characteristics). One-year mortality rate was 6.5% for the CA group and 36.9% for the no-CA group. In multivariate analysis, age, history of angina pectoris, presence of Q waves, Killip class at admission II, III, or IV and CPK ratio > or = 9 were significant predictors of a higher one-year mortality, but performance of CA did not significantly influence it: RR: 0.79 (95% CI 0.58 to 1.07).
Conclusions: Among patients with MI in a large unselected cohort in a French region, the one-year mortality was significantly lower in those referred for angiography. However, after correction for the confounding effects of simple baseline clinical indicators of risk, this apparent benefit reflected the fact that angiography was performed in those at lowest risk.