Background: Acute myocardial infarction (MI) in patients with chronic coronary artery disease is usually associated with a rupture of atherosclerotic plaque with subsequent thrombus formation and reduction or block of blood flow what leads to necrosis of myocardium supplied by occluded artery. In some patients with MI, there are no significant lesions in coronary arteries.
Aim: The comparative analysis of ST-segment elevation MI (STEMI) vs non-ST-segment elevation MI (NSTEMI) patients without significant angiographic lesions in short and long-term observation as well as identification of predictors of adverse long-term prognosis.
Methods: We analysed all subsequent patients hospitalised due to STEMI and NSTEMI, included in the Polish Registry of Acute Coronary Syndromes in years 2003-2006. Only patients without significant lesions in coronary arteries (stenosis ≤ 50%) were included. Patients were divided into two groups: STEMI and NSTEMI. In these groups we analysed in-hospital parameters, the frequency of cardiac adverse events during hospitalisation and mortality at 30 days, 6 months and 1 year.
Results: Patients with MI and no angiographically significant lesions in coronary arteries comprised 2.9% (n = 972) of all patients hospitalised due to MI (n = 32,959). Risk factors of coronary disease were observed more often in patients with NSTEMI. Mortality during hospitalisation, as well as after 30 days, 6 months, and 1 year was significantly higher in STEMI vs NSTEMI patients (3.5% vs 0.8%, 5.4% vs 0.8%, 8.15% vs 3.3%, 9.2% vs 4.6%).
Conclusions: 1. In-hospital and long-term prognosis was worse in STEMI vs NSTEMI patients. 2. The independent predictors of adverse long-term prognosis during 1 year observation are: older age, risk factors of coronary disease like diabetes mellitus and obesity, depressed left ventricular systolic function, cardiogenic shock and STEMI.