Pulse waveform analysis of optic nerve head circulation for predicting carotid atherosclerotic changes

To evaluate the relationship between the parameters of pulse waveform analysis in the optic nerve head using laser speckle flowgraphy (LSFG) and intima-media thickness (IMT) and severity of carotid arterial plaque.

Prospective and cross-sectional study.

One hundred seventy-six subjects were studied. Mean IMT and plaque score obtained from high-resolution B-mode ultrasound were evaluated. If mean IMT was 1 mm or greater, abnormal carotid artery thickening was diagnosed; if the plaque score exceeded 10, severe atherosclerosis was diagnosed. Blowout time and blowout score, which are parameters of pulse waveform analysis using LSFG, were evaluated. Logistic regression analyses determined the independent factors for abnormal carotid artery thickening and severe atherosclerosis. The cutoff levels for abnormal carotid artery thickening and severe atherosclerosis were analyzed using a conventional receiver operating characteristic (ROC) curve.

Logistic regression analysis showed that blowout time and body mass index contributed independently to abnormal carotid artery thickening, and blowout score contributed independently to severe atherosclerosis. The ROC curve showed that sensitivity and specificity of the blowout time and blowout score were equivalent to or greater than those of other factors. The cutoff level of the blowout time for abnormal carotid artery thickening was 46.4; the cutoff level of the blowout score for severe atherosclerosis was 71.8.

Measurement of blowout time and blowout score in the optic nerve head by LSFG can be useful for evaluating mean IMT and plaque score, which are parameters of carotid atherosclerosis.