Nonculprit Plaques in Patients With Acute Coronary Syndromes Have More Vulnerable Features Compared With Those With Non–Acute Coronary Syndromes

OBJECTIVES: Patients with acute coronary syndrome (ACS) have a higher incidence of recurrent ischemic events. The aim of this study was to compare the plaque characteristics of nonculprit lesions between ACS and non-ACS patients using optical coherence tomography (OCT) imaging.

METHODS: Patients who had 3-vessel OCT imaging were selected from the Massachusetts General Hospital (MGH) OCT Registry. MGH registry is a multicenter registry of patients undergoing OCT. The prevalence and characteristics of nonculprit plaques were compared between ACS and non-ACS patients.

RESULTS: A total of 248 nonculprit plaques were found in 104 patients: 45 plaques in 17 ACS patients and 203 plaques in 87 non-ACS patients. Compared with plaques of non-ACS patients, plaques of ACS patients had a wider lipid arc (147.3 ± 29.5° versus 116.2 ± 33.7°, P<0.001), a longer lipid length (10.7 ± 5.9 mm versus 7.0 ± 3.7 mm, P=0.002), a larger lipid volume index [averaged lipid arc×lipid length] (1605.5 ± 1013.1 versus 853.4 ± 570.8, P<0.001), and a thinner fibrous cap (70.2 ± 20.2 µm versus 103.3 ± 46.8 µm, 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) were more frequent in ACS 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 ± 67.0 µm versus 198.3 ± 133.0 µm, P=0.027).

CONCLUSIONS: Nonculprit lesions in patients with ACS have more vulnerable plaque characteristics compared with those with non-ACS. Neovascularization was more frequently located close to the lumen in patients with ACS. 

PMID: 22679059

Posted in Computed Tomography and tagged , , , .

2 Comments

  1. Nice study by Ik-Kyung Jang, MGH cardiologist, evaluating the vulnerable plaque with OCT. Our challenge is to use CT and MR to identify plaques with higher lipid content, thinner fibrous cap, and other signs of vulnerability. With higher resolution CT and better temporal resolution, as well as dual-energy CT we may be able to characterize the composition of many noncalcified plaques….

  2. Found this concept really intriguing!
    On OCT images, neovascularization was observed as a small black hole or a tubular structure within a plaque, similar to a microchannel. In the present study, the overall prevalence of microchannels in nonculprit lesions was not significantly different between ACS and non-ACS patients (64.7% versus 55.2%, respectively, P=0.647). However, the closest distance from the lumen to microchannel in the patient was shorter in ACS subjects than in non-ACS.” Somewhat reminiscent of the concept of ruptured vasa vasorum in aortic IMH… at a much more smaller level.

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