High intensity transient signals in patients with carotid stenosis may persist after carotid endarterectomy.
BACKGROUND
This study was undertaken to elucidate the natural history of high intensity transient signals (HITS) after carotid endarterectomy (CEA) and to determine whether this differs between patients with and without HITS detected preoperatively.


METHODS
A 30-min transcranial Doppler (TCD) recording was performed to detect HITS in 141 patients at 0-1 h, 2-3 h, 4-6 h and 24-36 h following CEA. 104 of these patients also had 30-min TCD monitoring within 48 h prior to CEA.


RESULTS
In the preoperative HITS-negative group, the proportion with postoperative HITS fell from 53% at 0-1 h to 17% at 24-36 h. In the preoperative HITS-positive group, the proportion with postoperative HITS remained steady (43% at 0-1 h, 52% at 24-36 h). During the 24-36 h postoperative epoch, 11 of 21 (52%) of the preoperative HITS-positive group had at least one HITS compared to 11 of 66 (17%) of the preoperative HITS-negative group (p = 0.001). In a multiple logistic regression analysis, preoperative HITS was the only factor associated with persistent postoperative HITS.


CONCLUSIONS
The proportion of cases with postoperative HITS diminished in the 24-36 h after CEA except for preoperative HITS-positive patients. About half of our patients undergoing CEA with preoperative HITS might have another embolic source.
Kimura
Kazumi
K
National Stroke Research Institute, Austin & Repatriation Medical Centre, Melbourne, Australia.
Stork
Jacinda L
JL
Levi
Christopher R
CR
Abbott
Anne L
AL
Donnan
Geoffrey A
GA
Chambers
Brian R
BR
D000368:Aged; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D016894:Endarterectomy, Carotid; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D017585:Ultrasonography, Doppler, Transcranial