Relation of Left Ventricular Infarct Transmurality and Infarct Size After Primary Percutaneous Coronary Angioplasty to Time from Symptom Onset to Balloon Inflation

This study was performed to evaluate the impact of time to reperfusion on infarct size and transmurality after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). In 73 patients undergoing primary PCI for STEMI, contrast-enhanced magnetic resonance imaging was performed. Infarct size and transmurality on delayed-enhancement imaging were measured. Infarct size was not associated with symptom onset-to-balloon time (23 ± 9% for <180 minutes, 22 ± 9% for 180 to 360 minutes, and 24 ± 11% for >360 minutes, p = 0.62) or door-to-balloon time (23 ± 8% for <90 minutes, 23 ± 10% for 90 to 120 minutes, and 22 ± 11% for >120 minutes, p = 0.88). Infarct transmurality increased significantly with a delay of symptom onset-to-balloon time (73 ± 22% for <180 minutes, 78 ± 14% for 180 to 360 minutes, and 86 ± 14% for >360 minutes, p = 0.04), but not for door-to-balloon time (79 ± 15% for <90 minutes, 76 ± 19% for 90 to 120 minutes, and 81 ± 18% for >120 minutes, p = 0.62). In multivariate analysis, anterior infarction (odds ratio 4.15, 95% confidence interval 1.31 to 13.18, p = 0.02) and myocardial blush grade 0/1 (odds ratio [OR] 3.89, 95% confidence interval [CI] 1.13 to 13.51, p = 0.03) independently predicted a large infarct (infarct size ≥25%). Symptom onset-to-balloon time (OR per 30 minutes 1.26, 95% CI 1.04 to 1.53, p = 0.02) was an independent predictor of transmural infarct (average transmural extent ≥75%) and use of glycoprotein IIb/IIIa inhibitors showed a protective effect (OR 0.09, 95% CI 0.02 to 0.53, p = 0.007). In conclusion, symptom onset-to-balloon time was significantly associated with infarct transmurality but not infarct size in patients undergoing primary PCI for STEMI.