Evaluation of acute ischemia in pre-procedure ECG predicts myocardial salvage after primary PCI in STEMI patients with symptoms > 12 hours

Background Primary percutaneous coronary intervention (pPCI) is recommended in patients with ST Elevation Myocardial Infarction (STEMI) and symptom duration < 12 hours. However, a considerable amount of myocardium might still be salvaged in STEMI patients with symptom durations > 12 hours (late-presenters). The Anderson-Wilkin's score (AW-score) estimates the acuteness of myocardial ischemia from the electrocardiogram (ECG) in STEMI patients. We hypothesized that the AW-score is superior to symptom duration in identifying substantial salvage potential in late-presenters. Methods The AW-score (range 1-4) was obtained from the pre-pPCI ECG in 55 late-presenters and symptoms 12-72 hours. Myocardial perfusion imaging was performed to assess area at risk before pPCI and after 30 days to assess myocardial salvage index (MSI). We correlated both the AW-score and pain-to-balloon with MSI and determined the salvage potential (MSI) according to AW-score ≥ 3 (acute ischemia) and AW-score < 3 (late ischemia). Results Late-presenters had median MSI 53% (inter quartile range (IQR) 27-89). The AW-score strongly correlated with MSI (β = 0.60, R² = 0.36, p < 0.0001), while pain-to-balloon time did not (β = - 0.21, R² = 0.04, p = 0.14). Patients with AW-score ≥ 3 (n = 16) compared to those with AW-score < 3 (n = 27) had significant larger MSI (82.7% vs 41.5%, p = 0.014). MSI > median was observed in 79% in patients with AW-score ≥ 3 vs 32% in patients with AW-score < 3 (adjusted OR 6.74 [95% CI 1.35-33.69], p = 0.02). Conclusion AW-score was strongly associated with myocardial salvage while pain-to-balloon time was not. STEMI patients with symptom duration between 12 -72 hours and AW-score ≥ 3 achieved substantial salvage after pPCI.