Epidemiology of acute myocardial infarction in the Italian CCU network: the BLITZ study

A large number of descriptive data on patients with acute myocardial infarction are based on clinical trials and registries on non consecutive patients: these data may give only a partial picture on treatment delay, patient characteristics, treatment and outcome of acute myocardial infarction in the real world.

The BLITZ survey prospectively enrolled all of the patients with acute myocardial infarction admitted in 296 (87%) Italian Coronary Care Units from 15-29 October 2001. Data on treatment delay, therapeutic strategies, duration of hospitalization and 30-day outcome were collected. One thousand nine hundred and fifty-nine consecutive patients (mean age 67+/-12 years, 70% males) were enrolled, 65% with ST-segment elevation (STEMI), 30% with no ST-segment elevation (NSTEMI) and 5% with undetermined ECG. The median delay between symptom onset and hospital arrival was 2h and 9 min with 76% of patients hospitalized within the sixth hour (26% within the first hour, 48% within the second). The median delay from hospital arrival to reperfusion therapy in STEMI was 45 min (IQR 26-85) for thrombolysis (50% of the patients) and 85 min (IQR 60-135) for primary angioplasty (15% of the patients). Coronary angiography was performed during hospital stay in 46% of the patients (STEMI 48%, NSTEMI 43%, undetermined AMI 35%), coronary angioplasty in 25% (STEMI 26%, NSTEMI 15%, undetermined AMI 13%) and coronary bypass in 1.4% (1%, 2.2% and 1% respectively). Twenty-two percent of the patients admitted to hospitals without cath-lab were transferred to a tertiary care hospital for invasive procedures. The overall median hospital stay was 10 days (IQR 7-12, STEMI 10, NSTEMI 9, undetermined AMI 11) and was not significantly different between hospitals with or without cath-lab (respectively, 9 and 10 days, P=0.38). After discharge and up to 30 days, coronary angiography was performed in 11% (STEMI 11%, NSTEMI 11%, undetermined MI 9%), angioplasty in 10% (STEMI 10%, NSTEMI 11%, undetermined MI 7%), bypass surgery in 7% (STEMI 5%, NSTEMI 11%, undetermined AMI 7%). The in-hospital and 30-day case fatality rates were 7.4% and 9.4%, respectively (7.5% and 9.5% for STEMI, 5.2% and 7.1% for NSTEMI, 18.2% and 21.2% for undetermined MI).

Patients with acute myocardial infarction admitted to the Italian CCUs, are older than those represented in clinical trials. A high proportion of these cases has the chance to receive early reperfusion therapy. Short-term mortality is lower than expected for patients with STEMI, but higher than reported for NSTEMI.