Abstract 4186: Impact of Culprit Lesion Characteristics on Microvascular Obstruction in Patients With Acute Coronary Syndrome: An Optical Coherence Tomography and Cardiac Magnetic Resonance Imaging Study
Background: The degree of myocardial damage is an important determinant of clinical outcomes in patients with acute coronary syndrome (ACS). We have reported that lesion characteristics are associated with slow flow phenomenon. The aim of this study was to investigate whether culprit lesion characteristics identified by optical coherence tomography (OCT) were associated with microvascular obstruction (MVO) assessed by contrast-enhanced magnetic resonance imaging (ce-MRI) in patients with ACS.
Methods: We enrolled 46 patients with ACS who were successfully recanalized with primary percutaneous coronary intervention (PCI). They were divided into a thin-cap fibroatheroma (TCFA) group (n=17) and a non-TCFA group (n=29) according to pre-intervention OCT findings of the culprit lesion. Using ce-MRI, we assessed transmural extent of infarction (TEI) that was graded from 1 to 4 based on the transmural extent of hyperenhanced tissue (1=0% to 25% of left ventricular wall thickness, 2=26% to 50%, 3=51% to 75%, and 4=76% to 100%) and MVO.
Results: There were no significant differences in patient’s characteristics between the two groups except for peak CK-MB (141±172 IU/L vs. 47±76 IU/L, p=0.01). Angiographical slow flow phenomenon was more frequently observed in the TCFA group compared with the non-TCFA group (35% vs. 9%, p=0.04). The TCFA group showed significantly higher TEI-grade (1.9±1.3 vs. 0.8±1.0, p=0.004). Furthermore, the frequency of MVO was significantly higher in patients with the TCFA group (35% vs. 3%, p=0.007).
Conclusions: Culprit lesion characteristics are associated with MVO after PCI, resulting in diminished coronary flow and high TEI-grade.