Supraorbital Opacity Pulses During Carotid Artery Compression: A Method for the Detection of Carotid Obstruction

Photoelectric plethysmography was employed to record amplitude changes in pulsatile blood flow from each of the supraorbital fields during carotid compression in 75 patients scheduled for carotid angiography. Tests were performed with patients in the supine position. Transducers were held in place with interposed translucent transfer tape. Circuitry was arranged to provide an upstroke during systole with sensitivity to record pulse waves between 10 and 20 mm in height. The common carotid arteries were compressed alternately for a duration of 4 to 6 pulses. Ratios of mean pulse wave amplitudes both before and during compression on the ipsilateral (I) and contralateral (C) sides were computed. Discriminatory analysis was employed to develop a test criterion with proper weights to ratios involving I and C. Employing this test criterion 67 percent (27 of 40) patients with radiologically significant carotid obstruction and 91 percent (32 of 35) without it were correctly identified. Tests on 11 additional patients correctly identified 4 of 5 with internal carotid obstruction and 6 of 6 without it. The results suggest that alteration of supraorbital opacity pulse amplitudes during carotid compression provides a rapid non-invasive test for unilateral carotid stenosis or occlusion.