Comparison of renin and catecholamine release in patients undergoing eversion or conventional carotid endarterectomy

Abstract

The two techniques for carotid endarterectomy (CEA)--conventional (C-CEA) and eversion (E-CEA)--have different effects on blood pressure. This study compared sympathetic activity after C-CEA and E-CEA, as measured by renin and catecholamine levels. E-CEA (n = 40) and C-CEA (n = 34) were performed in 74 patients with high-grade carotid stenosis. The choice of technique was made at the discretion of the operating surgeon. All patients received clonidine (150 μg) preoperatively. Regional anesthesia was used. The carotid sinus nerve was transected during E-CEA and preserved during C-CEA. Renin, metanephrine, and normetanephrine levels were measured preoperatively and at 24 and 48 hours postoperatively. Compared with baseline, levels of renin, metanephrine, and normetanephrine decreased at 24 and 48 hours after C-CEA (P < .0001). After E-CEA, however, renin and normetanephrine levels were unchanged at 24 hours, and metanephrine levels were increased (P < .0001). At 48 hours, levels of renin (P = .04), metanephrine (P < .0001), and normetanephrine (P = .02) were increased. Compared with C-CEA, E-CEA was associated with significantly increased sympathetic activity at 24 and 48 hours (P < .0001). Although the use of vasodilators for postoperative hypertension did not differ in the postanesthesia care unit (E-CEA 35% vs C-CEA 18%, P = .12), vasodilator use on the ward was more frequent after E-CEA (60% vs 32%, P = .02). E-CEA appears to be associated with greater postoperative sympathetic activity and vasodilator requirements than C-CEA, findings likely related to sacrifice of the carotid sinus nerve during E-CEA but not C-CEA.