Alterations of baroreflex sensitivity after carotid endarterectomy according to the preoperative carotid plaque echogenicity

Abstract

Baroreflex sensitivity is lower in patients with echogenic carotid plaques compared with patients with echolucent ones. The purpose of our study was to compare the baroreflex function after carotid endarterectomy (CEA) between patients with different plaque echogenicity. Spontaneous baroreflex sensitivity (sBRS), heart rate, and systolic and diastolic arterial pressure were calculated in 51 patients with a severe carotid stenosis (70%-99%) 24 hours before CEA, as well as 24 and 48 hours after CEA. Carotid plaque echogenicity was graded from 1 to 4 according to Gray-Weale classification, after duplex examination, and the patients were divided into two groups: the echolucent (grade 1 or 2) and the echogenic (grade 3 or 4). The postoperative mean systolic arterial pressure values in all 51 patients at 24 and 48 hours (143.2 and 135.5 mm Hg, respectively) were found to be significantly increased compared with the preoperative value (132.5 mm Hg; x2=32, P<.001). Mean sBRS value, in all patients, was significantly reduced postoperatively to 2.1 ms mm Hg(-1), from the mean preoperative value, 3.7 ms mm Hg(-1), independently of plaque echogenicity. Twenty patients (39%) were included in the echolucent group and 31 (61%) in the echogenic. The two groups had significant differences in two parameters: the rate of diabetes mellitus and the rate of symptomatic plaques. After adjusting the two groups for these differences, we found that the preoperative difference in sBRS between the two groups (F[1,51]=11, P<.003) was eliminated 24 and 48 hours after CEA (F[1,51]=.007, P<.9 and F[1,51]=.4, P<.5 for 24 and 48 hours, respectively). Before the removal of carotid atheroma, baroreflex sensitivity, which is a well established cardiovascular risk factor, seems to be affected by carotid plaque echogenicity. However, CEA has as a result a similar baroreflex response in all patients, regardless of plaque echogenicity, implying no association of plaque morphology and postoperative baroreflex sensitivity.