Presence of Plaque Neovascularization on Optical Frequency Domain Imaging Predicts Progression of Carotid Artery Stenosis

Abstract

Neovascularization (NV) is regarded to be one of the important features of vulnerable plaque. The purpose of this study was to evaluate associations between the presence of NV, detected using optical frequency domain imaging (OFDI), and ischemic events and the progress of carotid artery stenosis. Carotid artery plaques were evaluated using an OFDI system before angioplasty. NV was defined as no-signal tubuloluminal structures recognized on at least 3 consecutive images. The total number of NVs was compared between symptomatic and asymptomatic plaques and between progressive and nonprogressive plaques. Carotid plaque was diagnosed as "progressive" when peak systolic velocity increased between serial carotid duplex scans. A total of 36 patients (17 symptomatic, 16 progressive) were included. The percentage of patients with smoking habits was significantly higher with progressive carotid plaque than with nonprogressive carotid plaque (P= 0.003). NV was detected in 34 patients (94%), and the total number of NVs was significantly higher with progressive carotid plaque (10.2 ± 4.8 vs. 3.7 ± 2.8; P<0.0001). There was no relationship between the number of NVs and ischemic events (symptomatic 6.0 ± 5.1 vs. asymptomatic 7.1 ± 5.0; P= 0.47). In multivariate logistic regression analysis, the number of NVs was an independent predictor of progressive carotid plaque (odds ratio 1.64 per 1 increase [95% confidence interval 1.19-2.64]; P= 0.0005). NV was more frequently observed in progressive carotid plaques. Evaluation of NV using OFDI may be useful in predicting progressive carotid plaques.