Abstract 4183: Assessment of Morphological Features of Non-culprit Plaques in Patients With Acute Coronary Syndrome Using Optical Coherence Tomography
Background: Previous studies have shown that the culprit lesion in patients (pts) with acute coronary syndrome (ACS) had thinner fibrous cap and higher incidence of plaque rupture and thrombus formation. Although plaque instability might be expected to develop in a multifocal pattern, morphological features including fibrous cap thickness of non-culprit plaques have not been well established. Therefore, we assessed the morphological features of non-culprit plaques in pts with ACS using optical coherence tomography (OCT).
Methods: A total of 48 culprit and non-culprit coronary plaques (non-culprit vessel) in pts with coronary artery disease were interrogated by OCT before PCI. Pts were categorized according to their clinical presentation and location of the plaque: 19 culprit plaques in pts with ACS (ACS-C), 11 non-culprit plaques in pts with ACS (ACS-NC), and 18 culprit plaques in pts with stable angina pectoris (SAP). Minimal lumen diameter (MLD) and percent diameter stenosis (%DS) was measured by QCA. The fibrous cap thickness was measured at its thinnest part of the plaque, and the incidence of plaque rupture, thrombus formation, and thin-cap fibroatheroma (TCFA) was assessed by OCT.
Results: ACS-C group had smaller MLD and greater %DS than the others, while these parameters were similar between ACS-NC and SAP groups. The incidence of thrombus was higher in ASC-C group than in ACS-NC and SAP groups. Plaque rupture was more commonly observed in ACS-C, and less in SAP group. There was a trend for higher frequency of TCFA in ACS-C group. The fibrous cap thickness was thinner in both ACS-C and ASC-NC groups compared with SAP group, with lowest thickness in ACS-C group.
Conclusion: Although the incidence of thrombus in non-culprit lesion in pts with ACS was similar to culprit lesion in pts with SAP, the incidence of plaque rupture was higher and the fibrous cap thickness was thinner than those with SAP, which may account for the increased pan-coronary plaque vulnerability.