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

Abstract

BackgroundPrimary percutaneous coronary intervention (pPCI) is recommended in patients with ST Elevation Myocardial Infarction (STEMI) and symptom duration <12hours. However, a considerable amount of myocardium might still be salvaged in STEMI patients with symptom durations >12hours (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. MethodsThe 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 30days 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). ResultsLate-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). ConclusionAW-score was strongly associated with myocardial salvage while pain-to-balloon time was not. STEMI patients with symptom duration between 12 –72hours and AW-score ≥3 achieved substantial salvage after pPCI.