Complete revascularization of non-culprit lesions in stemi is associated with improved myocardial salvage and reduced microvascular obstruction: a cardiac magnetic resonance study

Abstract

Background The COMPLETE trial showed that routine and complete Percutaneous Coronary Intervention (PCI) of non-infarct related artery (non-IRA) lesions in STEMI was associated with a significant reduction in the rates of death or new myocardial infarction. However, whether this benefit is related to improved myocardial salvage and left ventricular (LV) function is unknown. Methods We prospectively included 465 patients with first STEMI reperfused by primary PCI. Late gadolinium-enhanced Cardiac Magnetic Resonance (CMR) was obtained during admission to measure the area at risk (AAR), IRA-infarct size (IS) as % LV mass, and myocardial salvage index (MSI) as % of AAR. The study was repeated in 392 of them at 6 months follow-up to compute LV volumes and ejection fraction (EF). Results Patients with three-vessel disease had larger IS than those with two or single vessel disease (25.4±14.5% vs 19.0±13.1% vs 19.0±12.8% LV mass respectively, p<0.05), despite no differences in AAR (33±11% LV mass for all). Accordingly, MSI decreased progressively for one, two or three-vessel disease (42.4±31.4 vs 41.5±30.6 vs 25.1±31.3% AAR respectively, p<0.01). The number of myocardial segments with microvascular obstruction (MVO) was also higher for three-vessel disease (1.9±1.9) than for two (1.1±1.7) or single-vessel disease (1.2±1.8), p<0.05. Mean follow-up EF also decreased progressively with the number of vessels involved (50.7±9.4, 49.1±11.4 and, 44.4±11.2% respectively, p<0.01). A total of 183 patients had multivessel disease. Among them, those with complete revascularization (n=51) had larger MSI (46.4±35.2 vs 34.5±29.3% AAR, p<0.04) and were less likely to have MVO phenomenon (28.6 vs 49.2%, p<0.05). However, no significant differences in the change in EF was observed between both groups (ΔEF:+4.4±6.2 vs +4.3±6.2%, p=0.985 for the interaction). Conclusion The presence and extent of multivessel disease influence myocardial salvage and MVO following primary PCI in STEMI. Improvement in myocardial salvage in the IRA territory and a reduction in microvascular obstruction may mediate the beneficial effects of complete revascularization. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Fundaciό La Marato TV3 2015303132, FIS PI15/00531. Partially funded with FEDER funds.