Coronary angioplasty as primary therapy for acute myocardial infarction 6 to 48 hours after symptom onset: Report of an initial experience

Abstract

Recent randomized trials in acute myocardial infarction suggest that infarct size reduction need not be achieved for intravenous streptokinase to improve patient survival. If this is the case, attempts to achieve late revascularization may be justified. To assess the results of late primary coronary angioplasty performed in the setting of acute myocardial infarction, the clinical and angiographic data as well as hospital outcome of 139 consecutive patients treated with coronary angioplasty without prior thrombolytic therapy 6 to 48 h after the onset of chest pain (late group) were compared with those of 117 patients treated with primary angioplasty <6 h after the onset of chest pain (early group); time to angioplasty was assessed as a covariate of survival.In the 139 patients treated ≥6 h after the onset of chest pain, the mean age (± SD) was 57 ± 12 years and the median time to angioplasty was 15 h; 61% had multivessel disease, 14% were in cardiogenic shock and the mean left ventricular ejection fraction was 44 ± 12%. Angioplasty was successful (final diameter stenosis <70% and Thrombolysis in Myocardial Infarction [TIMI] flow grade ≥2) in 78% of patients. Successful angioplasty was associated with a 5.5% in-hospital mortality rate, whereas unsuccessful angioplasty was associated with a 43% hospital mortality rate ( p < 0.001).Multivariate testing in all patients identified four independent predictors of in-hospital death: cardiogenic shock (p < 0.001), unsuccessful angioplasty (p = 0.001), ejection fraction ≤30% (p = 0.002) and patient age (p = 0.004). Time to angioplasty was not a predictor of outcome (p = 0.56). Unsuccessful angioplasty, however, was associated with a particularly high mortality rate in patients with anterior infarction or ejection fraction ≤30%. Thus, late emergency angioplasty may be justified when the likelihood of angioplasty success is very high. Randomized trials are needed to assess the utility of late coronary reperfusion in the setting of acute myocardial infarction.