Angiographic and magnetic resonance imaging evaluation of in-hospital delay in primary percutaneous intervention delivery on myocardial salvage

Shortening symptom-to-reperfusion time improves prognosis in patients with ST-segment elevation myocardial infarction. Accordingly, current guidelines target a door-to-balloon time <90 minutes, irrespective of symptom-to-door time; nevertheless, the relation between door-to-balloon and symptom-to-door time and its potential impact on myocardial salvage remains largely unknown. We investigated the influence of door-to-balloon guideline fulfillment on myocardial salvage in patients presenting with different symptom-to-door times. Contrast-enhanced magnetic resonance study was performed acutely to measure infarct size in 172 patients admitted for primary percutaneous coronary intervention of their first ST-segment elevation myocardial infarction to 2 tertiary hospitals. The Bari score was adapted to quantify the angiographic area at risk, and the myocardial salvage index (MSI) was computed as percent area at risk that spared necrosis. Increased symptom-to-balloon time was associated with a significant decrease in MSI only within the first 5 hours (p <0.001). Accomplishment of a target door-to-balloon <90 minutes was associated with a significant increase in MSI only in patients presenting within the first hour of symptom onset (48.5 ± 30.9 vs 29.6 ± 22.3%, p <0.05). Achieving a door-to-balloon time <60 minutes further increased MSI in patients presenting within the second hour of symptoms (43.5 ± 8.6 vs 26.3 ± 20.5%, p <0.01). In conclusion, myocardial salvage progressively decreases up to 5 hours after symptom onset. However, the benefit of the recommended door-to-balloon time appears to be confined to patients presenting within 1 hour of symptom onset.