Role of ST-Segment Resolution Alone and in Combination With TIMI Flow After Primary Percutaneous Coronary Intervention for ST-Segment-Elevation Myocardial Infarction

Abstract

Background To evaluate the role of ST-segment resolution (STR) alone and in combination with Thrombolysis in Myocardial Infarction (TIMI) flow in reperfusion evaluation after primary percutaneous coronary intervention (PPCI) for ST-segment-elevation myocardial infarction by investigating the long-term prognostic impact. Methods and Results From January 2013 through September 2014, we studied 5966 patients with ST-segment-elevation myocardial infarction enrolled in the CAMI (China Acute Myocardial Infarction) registry with available data of STR evaluated at 120 minutes after PPCI. Successful STR included STR ≥50% and complete STR (ST-segment back to the equipotential line). After PPCI, the TIMI flow was assessed. The primary outcome was 2-year all-cause mortality. STR < 50%, STR ≥50%, and complete STR occurred in 20.6%, 64.3%, and 15.1% of patients, respectively. By multivariable analysis, STR ≥50% (5.6%; adjusted hazard ratio [HR], 0.45 [95% CI, 0.36-0.56]) and complete STR (5.1%; adjusted HR, 0.48 [95% CI, 0.34-0.67]) were significantly associated with lower 2-year mortality than STR <50% (11.7%). Successful STR was an independent predictor of 2-year mortality across the spectrum of clinical variables. After combining TIMI flow with STR, different 2-year mortality was observed in subgroups, with the lowest in successful STR and TIMI 3 flow, intermediate when either of these measures was reduced, and highest when both were abnormal. Conclusions Post-PPCI STR is a robust long-term prognosticator for ST-segment-elevation myocardial infarction, whereas the integrated analysis of STR plus TIMI flow yields incremental prognostic information beyond either measure alone, supporting it as a convenient and reliable surrogate end point for defining successful PPCI. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01874691.

Keywords: ECG; acute myocardial infarction; outcome; reperfusion.

Figure 1. A flowchart for subject selection.

AMI indicates acute myocardial infarction; CABG, coronary artery bypass grafting; CAMI, China Acute Myocardial Infarction; NSTEMI, non–ST‐segment–elevation myocardial infarction; PPCI, primary percutaneous coronary intervention; STEMI, ST‐segment–elevation myocardial infarction; and STR, ST‐segment resolution.

Figure 2. Kaplan‐Meier curves for the 2‐year all‐cause mortality.

A, According to ST‐segment resolution (STR). B, According to concordant/discordant STR and Thrombolysis in Myocardial Infarction (TIMI) flow. Log‐rank test: P<0.001. Successful STR (SS) included STR ≥50% and complete STR.

Figure 3. Unadjusted hazard ratios (HRs) for the 2‐year all‐cause mortality according to clinical or angiographic subgroups.

*Successful ST‐segment resolution (STR) included STR ≥50% and complete STR. GPI indicates glycoprotein IIb/IIIa inhibitor; LVEF, left ventricular ejection fraction; and PCI, percutaneous coronary intervention.