Abstract

Aim. There are few studies comparing the treatment outcomes of different subtypes of acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI). We aimed to study the long-term outomes of patients with ST-elevation AMI (STEMI) and non-STEMI (NSTEMI) who have undergone PCI.

Methods. Patient data in the Estonian Myocardial Infarction Registry for years 2006−2009 in a tertiary care hospital, Tartu University Hospital, were linked with the Health Insurance Fund database and the Population Registry database. The primary outcome of the study was defined as non-fatal AMI, revascularization or death, whichever occurred first. All-cause mortal ity was studied as a secondary outcome. Hazard ratios (HR) with 95% confidence intervals (CI) for primary and secondary outcome were calculated using Cox regression adjusted for patients’ baseline characteristics and number of diseased coronary arteries.

Results. Of the 2330 AMI patients hospitalized during the study period, 1107 (82.9%) STEMI and 545 (54.8%) NSTEMI patients underwent PCI and were included in the final study sample. Compared to the NSTEMI patients, those with STEMI were more often current smokers and had acute heart failure at presentation to hospital; at the same time they had less often hypertension, previous AMI, chronic heart failure and revascularization. During the median follow-up of almost three years, compared to the NSTEMI patients, those with STEMI had higher rates of primary outcome (41.8% vs 34.8%, p = 0.007) and all-cause mortality (22.0% vs 15.4%, p = 0.001). The patients with STEMI had worse outcomes also after adjustment for basel ine characteristics ( HR for primary outcome 1.30 (95% CI 1.09−1.56)) and for all-cause mortality 1.57 (95% CI 1.19−2.08).

Conclusions. Among patients who have undergone PCI, those with STEMI have worse long-term outcomes than those with NSTEMI. This may be explained by the fact that NSTEMI patients who are referred to PCI have a lower cardiovascular risk than NSTEMI patients generally have.