CAROTID PLAQUE FEATURES ON ANGIOGRAPHY AND ASYMPTOMATIC CEREBRAL MICROEMBOLISM

We studied 110 carotid arteries of 55 patients with unilateral or bila teral carotid stenosis diagnosed with selective angiography, by using Transcranial Doppler to detect high intensity transient signals (HITS) in the middle cerebral arteries (MCAs). HITS identified as embolic si gnals were prevalent (P < 0.05) in the MCAs on the same side as severe (70-99%) stenosis (22 of 51 = 43.1%) compared to moderate (30-69%) st enosis (5 of 37 = 13.5%). No HITS were observed in the MCA on the same side as normal control carotid arteries (n = 17) [occluded arteries ( n = 5) were not considered]. HITS were more prevalent (P < 0.05) in th e MCAs on the same side as ulcerated plaques (14 of 23 = 60.9%) compar ed to non-ulcerated plaques (13 of 65 = 20%), and all moderate stenose s producing HITS presented ulceration of the plaque. Ulcerated plaque groups showed a higher mean number of HITS than non-ulcerated plaque g roups and no significant difference was noted between moderate and sev ere stenosis, between superficial or deep ulcerations and between ulce rations with flap or without flap. Therefore, severe carotid stenosis and moderate stenosis with plaque ulceration result in angiographic fi ndings most frequently associated with HITS. Further studies are neces sary to evaluate the clinical significance of this finding.