OBJECTIVES:Â PatientsÂ withÂ acuteÂ coronaryÂ syndrome (ACS) have a higher incidence of recurrent ischemic events. The aim of this study was to compare the plaque characteristics ofÂ nonculpritÂ lesions between ACS and non-ACSÂ patientsÂ using optical coherence tomography (OCT) imaging.
METHODS: PatientsÂ who had 3-vessel OCT imaging were selected from the Massachusetts General Hospital (MGH) OCT Registry. MGH registry is a multicenter registry ofÂ patientsÂ undergoing OCT. The prevalence and characteristics ofÂ nonculpritÂ plaquesÂ wereÂ comparedÂ between ACS and non-ACSÂ patients.
RESULTS: A total of 248Â nonculpritÂ plaquesÂ were found in 104Â patients: 45Â plaquesÂ in 17 ACSÂ patientsÂ and 203Â plaquesÂ in 87 non-ACSpatients.Â ComparedÂ withÂ plaquesÂ of non-ACSÂ patients,Â plaquesÂ of ACSÂ patientsÂ had a wider lipid arc (147.3 Â± 29.5Â° versus 116.2 Â± 33.7Â°, P<0.001), a longer lipid length (10.7 Â± 5.9 mm versus 7.0 Â± 3.7 mm, P=0.002), a larger lipid volume index [averaged lipid arcÃ—lipid length] (1605.5 Â± 1013.1 versus 853.4 Â± 570.8, P<0.001), and a thinner fibrous cap (70.2 Â± 20.2 Âµm versus 103.3 Â± 46.8 Âµm, P<0.001). Moreover, thin-cap fibroatheroma (64.7% versus 14.9%, P<0.001), macrophage (82.4% versus 37.9%, P=0.001), and thrombus (29.4% versus 1.1%, P<0.001) wereÂ moreÂ frequent in ACSÂ patients. Although the prevalence of microchannel did not differ between the groups, the closest distance from the lumen to microchannel was shorter in ACS subjects than in non-ACS (104.6 Â± 67.0 Âµm versus 198.3 Â± 133.0 Âµm, P=0.027).
CONCLUSIONS:Â NonculpritÂ lesions inÂ patientsÂ with ACS haveÂ moreÂ vulnerableÂ plaque characteristicsÂ comparedÂ with those with non-ACS. Neovascularization wasÂ moreÂ frequently located close to the lumen inÂ patientsÂ with ACS.