Background: Reperfusion therapy by primary coronary angioplasty has been shown to be beneficial for patients who present themselves up to 12 h after the onset of symptoms. However, the relationship between outcome and ischaemic time for patients who present relatively late after the onset of symptoms is still uncertain. The aim of this study was to investigate differences in patient characteristics, left ventricular function and clinical outcome among early (< 3 h), intermediate (3-6 h) and late (6-24 h) treated patients.
Methods and results: From August 1990 until December 1995, we studied 496 patients who underwent primary coronary angioplasty for acute myocardial infarction. Patients who underwent reperfusion therapy between 6 and 24 h were more often of female gender and more often had diabetes. Primary coronary angioplasty was less successful with later time to reperfusion. Patients who had reperfusion therapy within 6 h showed recovery of left ventricular function at 6 months follow-up, while the left ventricular function of patients treated late had deteriorated. Reocclusion of the infarct-related vessel at follow-up coronary angiography was highest for patients with an ischaemic time of more than 6 h. They more often suffered a repeat myocardial infarction and had a significantly higher 6 months mortality. After adjustment for age, heart rate at presentation, gender, and the presence of diabetes by multi-variate analysis, ischaemic time remained an independent predictor of both left ventricular function recovery and 6 month mortality.
Conclusions: The time from symptom onset to reperfusion is related to some baseline clinical characteristics, procedural success rate, left ventricular function and clinical outcome.