Introduction and methods
Patients with acute coronary syndrome (ACS) examined in Zagreb Clinical Centre Emergency Room can be admitted either to the coronary unit (CU), the general medical ICU (ICU) or one of cardiology wards (CW). For all the patients there has been a unique coronary intervention unit available on a 24-hour basis since January 2001. In the year 2002 there were 5731 emergency admissions (33.8% of 16,924 patients examined). All 681 patients with ACS, 318 with myocardial infarction (MI) and 363 with unstable angina (UA) were retrospectively analysed. The aim was to determine predictors of mortality and differences in treatment and hospital mortality (as a measure of quality of care) in the CU, the ICU and the CW. Number of admissions and diagnoses varied due to different unit profiles and capacities: 237 (195 MI, 41 UA) to the CU, 87 (60 MI, 27 UA) to the ICU, and 237 (60 MI, 286 UA) to the CW. Chi-square and nonparametric tests were used in statistical analyses.
There were no statistically significant age (P = 0.265) or sex (P = 0.386) differences between patients in different units. No statistically significant difference (P = 0.659) in hospital mortality of patients with MI in the CU (14.3%), the ICU (13,9%) or the CW (21,4%) was found. The proportion of patients with AMI on which coronary angiographies and subsequent percutaneous coronary intervention (PCI) was performed did not differ significantly (P = 0.635) in the CU, the ICU and the CW (74.7%, 65.52% and 44.44%, respectively). The proportion of patients with UA to whom PCI was performed in the same hospital stay did not differ significantly (P = 0.59). All patients undergoing PCI were treated with clopidogrel 1 month following. Age, sex, hypertension, smoking, diabetes, coronary artery disease (CAD), previous MI, high cholesterol, localisation of MI were tested (through univariate analysis) for association with hospital mortality. The following were found to be associated: age (P = 0.0001), female sex (P = 0.0471), history of CAD (P = 0.0196) or MI (P = 0.012), high cholesterol (P = 0.0276) and smoking (P = 0.0142). Patients treated with PCI had significantly (P = 0.0001) lower hospital mortality (6.3%) than those not treated (32.0%). Not-treated patients were significantly older, but lower mortality of treated patients was significant in every 10-year age range tested (highest P = 0.012).
PCI significantly decreases hospital mortality of patients with MI. Although patients with ACS could be admitted to different types of units, no significant difference was found in hospital mortality or treatment strategy. Several hospital morality risk factors were identified: age, female sex, previous MI or CAD, high cholesterol and smoking.