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. Conclusion: 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. Copyright (C) 2004 S. Karger AG, Basel.