Abstract
A retrospective analysis of 1500 patient records was performed to assess the validity and reliability of combined oculoplethysmography and carotid phonoangiography (OPG/CPA) as indicators of carotid arterial occlusive disease. The tests were interpreted by means of a five-level grading system based on percentage of flow reduction. Reliability statistics were calculated by using arteriography as a comparison in 10% (152) of the patients.
Of the 1500 tests, 477 (32%) were abnormal, but only 252 (17%) were graded as hemodynamically significant (levels II-V). Arteriography confirmed total carotid occlusion in 16 of 19 (84%) grade V patients; the remaining 3 (16%) had significant stenosis but on a less severe level (III or IV). In the inter mediate grade II-IV results, 39 of 44 (89%) were accurate; 2 (4%) false positive and 3 (7%) overestimated cases were in this group. In the normal- grade I patients, 81 of 89 (91%) interpretations were confirmed. The false negatives (9%) in the latter group were attributable to nonstenosing ulcera tive plaques (6 patients) and moderately significant stenosis (2 patients). Overall reliability was 90%, with 1% false positives, 4% false negatives, and about 5% erroneous assessment of severity within the abnormal grades II-V. Thus OPG/GPA testing is a valuable, reliable, noninvasive screening and diagnostic tool for carotid disease detection, but it is sensitive only to stenotic lesions, not to ulcerative plaques.
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