Early postoperative morphology of the carotid artery following endarterectomy: systematic prospective studies with a high resolution ultrasound real-time imaging system

Abstract

The ultrasonic morphology of the carotid artery following 55 endarterectomies in 50 patients was systematically studied using a high resolution ultrasound duplex system. The typical findings were: At the site of endarterectomy the new vessel wall showed: lack of the "sonographic tunica intima"; the thickness of the vessel wall was reduced with less pronounced ultrasonic structure compared with healthy subjects; the surface toward the lumen was less smooth; "ultrasonically soft" thrombotic layers with irregular surface, individual distribution (sometimes only spots) and thickness (0.5 to 4.0 mm) were seen in the majority of patients. The edge of the tunica intima was always visible in the common carotid (edge of endarterectomy), whereas in the internal carotid artery there was often an interference of the jaw. The change of caliber at the site of the edge of the tunica intima was dependant on the thickness of the "sonographic intima" as well as on the layer of the vessel wall in which endarterectomy was done. At the site of arterial clamping intramural haematomas, lesions of the tunica intima with thrombotic layers causing some stenosis were observed after 9 of 55 procedures. Vascular sutures were always visible as bright spots. A "normalisation" of the pulsatory motion of the vessel wall as well as "normalisation" of local flow patterns could be seen in dependence on the morphological "normalisation". The soft thrombotic layers of the new vessel wall were especially pronounced at sites of incomplete endarterectomy, in one case with change of the vessel geometry and in another case were the opposite carotid was operated on 3 days later. Obviously, a short phase of high instability of the endarterectomy site (3 days, development of the platelet-fibrin layer) is followed by a period of relative instability of the new vessel wall, which lasted for 4 to 8 weeks. In 5 patients with central neurological deficits following surgery, especially pronounced soft thrombotic layers of the new vessel wall including 2 complete occlusions and 1 near-occlusion were observed.