Relation between electrocardiographic ST-segment resolution and early and late outcomes after primary percutaneous coronary intervention for acute myocardial infarction.

ST-segment resolution (STR) is a surrogate end point in reperfusion trials of acute myocardial infarction, but there are few data regarding the optimum methods of measurement, clinical predictors, and correlation with late cardiac mortality. Consecutive patients (n = 1,005) who had acute myocardial infarction and >/=2 mm ST-segment elevation controlled with primary percutaneous coronary intervention (PCI) constituted our study group. Follow-up was obtained in 97% of patients at a median of 6.2 years. STR measured as maximum ST-segment elevation after PCI provided better discrimination of late cardiac mortality than did STR measured as percent resolution. Complete STR (<1.0 mm ST-segment elevation after PCI) was achieved in only 42% of patients. Anterior infarction, Killip's class 3 to 4, and Thrombolysis In Myocardial Infarction flow grades <2 before PCI and <3 after PCI were strong independent predictors of partial or poor STR. STR (complete [<1.0 mm] vs partial [1.0 to 2.0 mm] vs poor [>2.0 mm]) correlated with in-hospital mortality (4.0% vs 6.7% vs 11.6%, p = 0.005), reinfarction (1.4% vs 3.4% vs 6.1%, p = 0.01), and late cardiac mortality (17% vs 25% vs 44%, p <0.0001). Correlation with late mortality was stronger for nonanterior than for anterior infarction. Poor STR was a strong independent predictor of late mortality (hazard ratio 1.63, 95% confidence interval 1.06 to 2.50, p = 0.028), even after adjusting for Thrombolysis In Myocardial Infarction flow. These data support the use of STR as a simple method to stratify patients by risk after primary PCI for acute myocardial infarction and support the use of STR as a surrogate end point in reperfusion trials of acute myocardial infarction.

Importance of time-to-reperfusion in patients with acute myocardial infarction with and without cardiogenic shock treated with primary percutaneous coronary intervention.

BACKGROUND: Time-to-treatment is important for survival in patients with acute myocardial infarction (AMI) treated with fibrinolytic therapy, but the importance of time-to-treatment with primary percutaneous coronary intervention (PCI) is controversial. Previous studies evaluating the importance of time-to-treatment with primary PCI have not analyzed patients with cardiogenic shock separately. METHODS: Consecutive patients with AMI (n = 1843) treated with primary PCI were prospectively enrolled in the LeBauer Cardiovascular Research Foundation Registry. Late clinical follow-up was obtained in 98% of patients, at a mean time of 6.1 years. RESULTS: Reperfusion times were longer in women and patients with diabetes mellitus and shorter in patients with prior myocardial infarction. In patients with shock (n = 138), the inhospital mortality rate increased progressively with increasing time-to-reperfusion (<3 hours, 31%; 3-<6 hours, 50%; > or =6 hours, 62%; P =.01), whereas in patients without shock (n = 1705), inhospital and late mortality rates were similar across 3 categories of time to reperfusion (<3 hours, 5.8%; 3-<6 hours, 4.6%; > or =6 hours, 4.8%; P =.46). After adjusting for differences in baseline variables, reperfusion time was a significant independent predictor of inhospital mortality in patients with shock, but not in patients without shock. CONCLUSIONS: Reperfusion time with primary PCI is important for survival in patients with shock, but appears to be less important in patients without shock. These data emphasize the importance of achieving early reperfusion in patients with shock and have implications on the triage of patients without shock for mechanical reperfusion and the mechanism of benefit of reperfusion therapy with primary PCI.

Effect of treatment delay on outcomes in patients with acute myocardial infarction transferred from community hospitals for primary percutaneous coronary intervention.

Outcomes were evaluated in 1,841 consecutive patients with acute myocardial infarction treated with primary percutaneous coronary intervention from 1984 to 2000 comparing patients transferred from community hospitals (n = 680) with patients presenting locally (n = 1,161). Baseline variables were similar except transferred patients had fewer prior infarctions (13% vs 21%, p <0.001) and underwent less prior bypass surgery (2.8% vs 6.0%, p = 0.002). Median times from symptom onset to emergency department arrival were similar, but door-to-balloon times and reperfusion times were approximately 1 hour longer in transferred patients (2.8 vs 1.9 hours [p <0.001] and 4.5 vs 3.5 hours [p <0.001], respectively). Despite longer treatment times, there were no significant differences between transferred and nontransferred patients in 30-day mortality (7.6% vs 8.1%, p = 0.73), reinfarction, urgent target vessel revascularization, stroke, and late mortality. After adjusting for differences in baseline variables, mortality remained similar between transferred and nontransferred patients (odds ratio 0.90, 95% confidence interval 0.59 to 1.36). Peak cardiac enzyme values were higher in transferred patients, but there were no differences in 6-month ejection fractions between groups. In conclusion, patients transferred from community hospitals for primary percutaneous coronary intervention have almost 1-hour additional treatment delay, but this does not appear to have a major adverse effect on clinical outcomes. These data should encourage further randomized trials to evaluate the role of transfer for mechanical reperfusion in patients presenting to community hospitals with acute myocardial infarction.