Acute myocardial infarction (MI) is invariably caused by near total or total occlusion of epicardial coronary arteries by a thrombus superimposed on an unstable atheromatous plaque. However, normal coronary arteries on angiograms performed in patients with acute myocardial infarction have been described. The aim of our study was to see if and how often myocardial infarction occurs in the setting of normal coronary arteries visualized by angiography in patients seen in a community hospital.
All coronary angiograms done in Coney Island hospital from January 1995 to July 2002 were reviewed. 1699 patients with normal coronary arteries were identified. These charts were reviewed for evidence of acute myocardial infarction based on EKG findings and presence of elevated cardiac enzymes. Potential causative factors for myocardial infarction and incidence of ST elevation MI (STEMI) versus non-ST elevation MI (NSTEMI) were also studied.
We identified 17/1699 (1%) patients who presented with acute myocardial infarction with normal coronary arteries by angiography. Mean age - 52.75; Age range - 24 to 81; Male - 10, Female 7, M/F - 1.5:1. 6/17 (35.3%) had STEMI. 5/6 (83.3%) had potential causative factors (3/5 had cocaine abuse, 1/5 had hyperviscosity due to polycythemia, 1/5 had hypercoaguable state due to lupus anticoagulant). 11/17 (64.7%) had NSTEMI. Only one of these 11 patients (9.1%) had an identifiable cause (cocaine abuse).
Normal coronary arteries on angiography essentially excludes acute myocardial infarction. In rare instances when it occurs, potential causative factors include cocaine abuse, hypercoaguable disorders and hyperviscosity states.
Patients with acute myocardial infarction and normal coronary angiogram must be evaluated for potential causative factors, such as cocaine abuse, hypercoaguable disorders and hyperviscosity states, specially in patients with STEMI.
Muhammad Rehman, None.