Prognostic implication of ST-segment resolution following primary percutaneous transluminal coronary angioplasty for ST-elevation acute myocardial infarction

Background : ST‐segment changes have been shown to correlate with myocardial tissue perfusion. Complete ST‐segment resolution after thrombolysis in acute myocardial infarction is associated with lower mortality and better left ventricular function. Primary percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction restores better epicardial coronary flow to the infarct‐related artery than thrombolysis. However, ST changes may persist and flow can remain poor despite a patent vessel. Aim : To examine the prognostic implication of ST‐segment resolution immediately following primary and rescue PTCA for ST‐elevation acute myocardial infarction (STEMI). Methods: Records of 201 consecutive primary and rescue PTCA performed at Westmead Hospital for STEMI from January 2000 to December 2001 were reviewed. ST‐segment elevation (taken 20 ms after the end of the QRS complex) was measured immediately before and after the procedure. ST‐segment resolution of greater than 70% after the procedure was considered as ­‘complete’ ST‐segment resolution, whereas ST‐segment resolution of less than 70% was considered as ‘incomplete’ ST‐segment resolution. Results : Of the 201 patients, 117 (58%) had complete ST‐elevation resolution and 84 (42%) did not. There was a significant difference in survival free of major adverse cardiovascular events; 60% of those with complete ST‐segment resolution were event‐free at 2 years compared with 35% of those patients without complete ST‐segment resolution. Conclusion : ST‐segment resolution after primary and rescue PTCA for STEMI is associated with significantly higher event‐free survival. The goal of primary angio­plasty should be the restoration of normal epicardial flow with normalization of ST‐segments. (Intern Med J 2004; 34: 551−556)