Relationship between ST-segment recovery and clinical outcomes after primary percutaneous coronary intervention: the HORIZONS-AMI ECG substudy report.

BACKGROUND In patients with ST-segment elevation myocardial infarction undergoing thrombolytic therapy, the degree of ST-segment resolution (STR) correlates with long-term cardiovascular mortality. The long-term predictive value of STR after primary percutaneous coronary intervention (PCI) is less well understood. We sought to determine the long-term prognostic value of STR after primary PCI in ST-segment-elevation myocardial infarction. METHODS AND RESULTS In a formal substudy from the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, 2484 patients with ST-segment-elevation myocardial infarction undergoing primary PCI with interpretable baseline and 60-minute post-PCI electrocardiograms had at least 1 mm of baseline ST-segment elevation in ≥2 contiguous leads. Patients were categorized by the degree of STR at 60 minutes: (1) complete (>70%); (2) partial (30%-70%); and (3) absent (<30%). Absent, incomplete, and complete STR were achieved in 514 (20.7%), 712 (28.7%), and 1258 (50.5%) patients, respectively. STR <30% was associated with a greater likelihood of hypertension, diabetes mellitus, longer symptom onset to balloon time, lower left ventricular ejection fraction, and final thrombolysis in myocardial infarction flow <3. At 3 years, patients with STR<30% experienced a higher rate of major adverse cardiovascular events (death, reinfarction, ischemia-driven target vessel revascularization or stroke; 29.9% versus 20.1% versus 19.6%; P<0.0001), ischemia-driven target vessel revascularization (20.4% versus 14.0% versus 11.7%; P<0.001), and mortality (8.4% versus 5.0% versus 5.6%; P=0.03) than those with partial and complete STR, respectively. By multivariable analysis, STR<30% was an independent predictor of 3-year major adverse cardiovascular events (hazard ratio, 1.58; 95% confidence interval, 1.24-2.00; P=0.0002) and 3-year ischemia-driven target vessel revascularization (hazard ratio, 1.87; 95% confidence interval, 1.41-2.48; P<0.0001). CONCLUSIONS In this large international study, absent STR 60 minutes after primary PCI was present in ≈1 in 5 patients with ST-segment-elevation myocardial infarction and was a significant independent predictor of major adverse cardiovascular events and target vessel revascularization at 3 years.