Choroidal vascularity index of patients with coronary artery disease

Abstract

We investigated the changes in subfoveal choroidal thickness and choroidal vascularity index (CVI) and their relationship with the severity of coronary artery stenosis in patients with cardiovascular risk factors and symptoms suggestive of coronary artery disease (CAD). Ninety patients who underwent coronary angiography (CAG) for evaluation of their coronary artery status and cardiac symptoms were included. Forty-two patients showed no evidence of CAD; 31 patients had one to two vessel disease; and 17 had a triple vessel disease. There were no significant differences in the subfoveal choroidal thickness among the three groups; however, the CVI in the triple vessel disease group was lower than those in the other groups. The CVI values were good predictors of the presence of triple-vessel disease (p = 0.020). Multivariate logistic regression analysis results revealed that male sex (odds ratio 5.4, p = 0.049), hypertension (odds ratio 4.9, p = 0.017), and CVI (%, odds ratio 0.8, p = 0.016) were significant factors associated with the presence of triple vessel disease. Although CVI may not be a sensitive marker for detecting early changes in the coronary artery, it may be helpful in indicating severe CAD.

Figure 1

Choroidal vascularity index measurements. (A) The center of the fovea is marked with a built-in arrow tool (yellow arrow). (B) The outer boundary of the choroid is manually drawn (red line). (C) The lower border of the hyperreflective band of RPE/Bruch's membrane complex (upper red line) and the choroidal area of a predetermined range centered on the fovea are automatically extracted (green border area). (D) The subfoveal choroidal thickness (SCT) is automatically calculated. (E) Binarized images are obtained using the Niblack thresholding. (F) Despeckled image with the removal of particles with less than 20-pixels in size. (G–I) The choroidal vascularity index (CVI) is calculated as the ratio of the luminal area (dark area) to the total choroidal area in various choroidal ranges (1500 μm, 3000 μm, and 5000 μm) using both the original (CVI₁) and despeckled (CVI₂) binarized images.

Figure 2

Receiver operating characteristic curve for predicting triple vessel disease using the choroidal vascularity index. The maximum sum of sensitivity and specificity was observed with CVI value cut-off points of 0.604, 0.601, and 0.600 for CVI without despeckling in 1500 μm, 3000 μm, and 5000 μm range analyses, respectively, and CVI value cut-off points of 0.624, 0.630, and 0.628 for CVI with despeckling in 1500 μm, 3000 μm, and 5000 μm range analyses, respectively. CI = confidence interval.