Abstract 249: Impact of Primary Coronary Angioplasty Delay on Myocardial Salvage, Infarct Size and Microvascular Damage in Patients With ST-Elevation Myocardial Infarction: Insight From Cardiovascular Magnetic Resonance
Background: Previous studies evaluating the influence of time-to-reperfusion on infarct size (IS) and myocardial salvage in patients with ST-segment elevation myocardial infarction (STEMI) yielded conflicting results. We aimed to investigate the extent and nature of myocardial damage using cardiovascular magnetic resonance (CMR) in relation to different time-to-reperfusion intervals.
Methods: Seventy patients with STEMI successfully treated with primary PCI within 12 hours from symptom onset, underwent CMR 3±2 days after hospital admission. Patients were subcategorized into 4 time-to-reperfusion (symptom onset to balloon) quartiles: >90 minutes (group I, n= 19), >90 –150 minutes (group II, n= 17), >150 –360 minutes (group III, n= 17), and >360 minutes (group IV, n= 17). T2w-STIR and LGE CMR was used to characterize reversible and irreversible myocardial injury (area at risk and infarct size, respectively); salvaged myocardium was defined as the normalized difference between extent of T2w-STIR and LGE.
Results: Shorter time-toreperfusion (group I) was associated with smaller IS and MVO and larger salvaged myocardium. Mean IS progressively increased overtime: 8% (group I), 11.7% (group II), 12.7% (group III), 17.9% (group IV), p=0.005; similarly MVO was larger in later reperfused patients (0.5%, 1.5%, 3.7%, 6.6%, p=0.039, respectively). Accordingly, salvaged myocardium markedly decreased when reperfusion occurred > 90 minutes of coronary occlusion (8.5%, 3.2%, 2.4%, 2.1%, p =0.003, respectively).
Conclusions: In patients with STEMI treated with primary PCI, time-to-reperfusion determines the extent of reversible and irreversible myocardial injury assessed by CMR. In particular, salvaged myocardium is markedly reduced when reperfusion occurs >90 minutes of coronary occlusion. CMR could be a potentially valuable tool to be used in large clinical trials assessing the efficacy of different reperfusion strategies.