Impact of ST-segment resolution after primary angioplasty on outcomes after myocardial infarction in elderly patients: An analysis from the CADILLAC trial

Background Age is a strong independent predictor of outcomes after primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI). Whether lower rates of reperfusion success contribute to the poor prognosis in elderly patients is unknown. Methods A formal ST-segment analysis substudy was performed in 695 patients undergoing primary PCI for AMI in the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial. Reperfusion success (determined by the magnitude of ST-segment elevation resolution [STR] after PCI) was evaluated in 4 age groups: <50 years (n = 163), ≥50 to <60 years (n = 187), ≥60 to <70 years (n = 194), and ≥70 years (n = 151). Results There were no differences in the age groups for angiographic procedural success (>91% in all, P = .6), postprocedural Thrombolysis in Myocardial Infarction grade 3 flow (>94%, P = .8), and the proportions of patients with complete, partial, or absent STR (P >.8). However, rates of 30-day mortality (0.6%, 1.1%, 3.6%, 6.0%, respectively) and major adverse cardiac events (MACE; 2.5%, 4.8%, 6.2% 9.3%, respectively) increased with age. Rates of mortality and MACE were also inversely related to the magnitude of STR. Absent STR (hazard ratio, 3.00; 95% CI, 1.37-6.58; P = .006) and age (hazard ratio, 1.34; 95% CI, 1.01-1.77; P = .04) were independent predictors of 30-day MACE by using multivariable modeling. Conclusions Lack of effective myocardial reperfusion is not a contributory mechanism responsible for the high morbidity and mortality rates observed in elderly patients. Nevertheless, advanced age and absent STR are both independent predictors of adverse outcomes after primary PCI, emphasizing the importance of successful reperfusion in the elderly population.