Time Delay, Infarct Size, and Microvascular Obstruction After Primary Percutaneous Coronary Intervention for ST-Segment-Elevation Myocardial Infarction.

BACKGROUND: Symptom-to-balloon time (SBT) and door-to-balloon time (DBT) are both considered important metrics in patients undergoing primary percutaneous coronary intervention (pPCI) for ST-segment-elevation myocardial infarction (STEMI). We sought to assess the relationship of SBT and DBT with infarct size and microvascular obstruction (MVO) after pPCI. METHODS: Individual patient data for 3115 ST-segment-elevation myocardial infarction patients undergoing pPCI in 10 randomized trials were pooled. Infarct size (% left ventricular mass) was assessed within 1 month after randomization by technetium-99 m sestamibi single-photon emission computerized tomography (3 studies) or cardiac magnetic resonance imaging (7 studies). MVO was assessed by cardiac magnetic resonance. Patients were stratified by short (≤2 hours), intermediate (2-4 hours), or long (>4 hours) SBTs, and by short (≤45 minutes), intermediate (45-90 minutes), or long (>90 minutes) DBTs. RESULTS: Median [interquartile range] SBT and DBT were 185 [130-269] and 46 [28-83] minutes, respectively. Median [interquartile range] time to infarct size assessment after pPCI was 5 [3-12] days. There was a stepwise increase in infarct size according to SBT category (adjusted difference, 2.0% [95% CI, 0.4-3.5] for intermediate versus short SBT and 4.4% [95% CI, 2.7-6.1] for long versus short SBT) but not according to DBT category (adjusted difference, 0.4% [95% CI, -1.2 to 1.9] for intermediate versus short DBT and -0.1% [95% CI, -1.0 to 3.0] for long versus short SBT). MVO was greater in patients with long versus short SBT (adjusted difference, 0.9% [95% CI, 0.3-1.4]) but was not different between patients with intermediate versus short SBT (adjusted difference, 0.1 [95% CI, -0.4 to 0.6]). There was no difference in MVO according to DBT. Results were similar in multivariable analysis with SBT and DBT included as continuous variables. CONCLUSIONS: Among 3115 patients with ST-segment-elevation myocardial infarction undergoing infarct size assessment after pPCI, SBT was more strongly correlated with infarct size and MVO than DBT.

Duke Scholars

Author Manesh Raman Patel Medicine, Cardiology

Author Christopher Bull Granger Medicine, Cardiology