Comparison of in-hospital outcomes following early or delayed angioplasty for acute myocardial infarction

Background. Studies of primary angioplasty for treatment of acute myocardial infarction (AMI) have not appeared to demonstrate a reduction in efficacy as a function of time to treatment. We sought to compare the outcomes of patients treated in New York State with primary angioplasty within 6 hours of symptom onset to those treated between 6 and 23 hours after the onset of AMI.Methods. We used data from the 1995 Coronary Angioplasty Reporting System of the New York State Department of Health to compare the in-hospital outcomes of patients treated with early (within 6 hours) or delayed angioplasty (6-23 hours) for AMI. Results. Early angioplasty (within 6 hours after onset of chest pain) was attempted in 957 patients (71.3%), while 385 patients (28.7%) had a delayed procedure (6-23 hours after the onset of chest pain). Patients who underwent delayed angioplasty were older (mean age, 62.6 years versus 60.4 years in the early group; p < 0.01) and more often female (36% vs. 28% in the early treatment group; p < 0.001). Patients treated early more frequently demonstrated hemodynamic instability (13.6% versus 9.1% in the late treatment group; p = 0.02), malignant ventricular arrhythmia (8.5% versus 2.9% in the late treatment group; p < 0.001) and cardiogenic shock (6.6% versus 1.8% in the late treatment group; p < 0.001). Overall in-hospital mortality was 63/1,342 (4.7%) with no difference based on early or delayed angioplasty (5.2% versus 3.4%, respectively; p = NS). The composite of the major adverse cardiac events including in-hospital death, reinfarction and emergency bypass surgery did not differ significantly between the early and delayed groups (7.7% versus 5.5%, respectively; p = NS). In multivariable models, delayed angioplasty was not an independent predictor of either in-hospital mortality or major adverse cardiac events. Conclusion. Delayed reperfusion does not influence inhospital clinical outcomes following PTCA for acute myocardial infarction.