Monitoring middle cerebral artery blood velocity during carotid endarterectomy

510

Journal of VASCULAR SURGERY

Abstmts

sue culture has shown the secretion of proteases, which could be responsible for endothelial sloughing. The demonstration of substantially less inflammation and endothelial loss in the high flow grafts may be due to either more rapid dilution of chemoattractant agents or to the effects of higher shear stress on the vessel wall. In this model, the benefit of steroid administration results directly from inhibition of i&rnrnation and its injury to endothelium. It is hoped that reduction of the acute inflammation will reduce the fibrosis and subintimal hyperplasia and thus improve patency of vein grafts, especially in low flow situations. J. Dennis Baker, MD. UCLA School of Medicine

The authors conclude that the use of the sutureless intraluminal prosthesis may be of value in the patient with a friable infrarenal aorta but acknowledge that the value of the graft would be greatly enhanced if the technical problems associated with the iliac anastomoses could be overcome. Charles Lye, M.D. University of Manitoba

Monitoring middle cerebral artery blood velocity during carotid endarterectomy Padayachee T, Gossling S, Biship RG, et al. Br J Surg 1986;73:98-100. The authors report that intraoperative monitoring of middle cerebral blood velocity duiing crotid endarterectomy has been achieved by means of a transcranial pulsed Doppler ultrasound. The spectral analysis of the blood flow ofthe middle cerebral arterv was correlated with the various stages of the operation. In 19 patients, the authors demonstrate that there is a decrease in the middle cerebral artery blood velocity during carotid clamping. Blood velocity returns to normal or increases with placement of a carotid shunt. In several patients, during back-bleeding of the internal carotid artery, there was a reversal of flow in the middle cerebral artery, suggesting a shunt phenomenon. This is the first report of a study of intraoperative middle cerebral artery blood flow in the literature and it is remarkable for observing intracerebral blood flow changes during the maneuvers of carotid surgery. The authors do not know whether there is any particular significance regarding the changes of blood velocity of the middle cerebral artery. Specifically, it is too early to know whether this technique will be able to select which patients will have cerebral ischemia with carotid clamping since there were no concomitant measurements of cerebral ischemia in this study. Further studies will be needed to determine whether this technique will provide a means of monitoring patients during carotid surgery. I

Use of a ringed intraluminal graft in the operative management of abdominal aortic aneurysms Cave-Bigley DJ, Harris PL. Br J Surg 1985; 72:825-7. The authors report their early experience with a nonsutured intraluminal aortoiliac graft for the treatment of aortic aneurysm. Steel rings covered with double-velour Dacron are added to the three ends of a Dacron bifurcation graft. The proximal end of the graft is anchored within the aortic ring, which in turn is grooved around its outer surface to allow an encircling Dacron tape to anchor the neck of the aneurysm to the ring. The iliac rings are adjustable over the iliac limbs to facilitate choice of an appropriate limb length. Alternatively, the iliac rings could be discarded to allow for conventional suture anastomoses. The intent of the procedure is to allow for reduced technical difficulty, operating time, and blood loss in high-risk patients. Grafts were placed in 20 patients, including 12 patients with ruptured aneurysms. Placement of the proximal ring was generally straightforward and significantly aided by the use of proximal intra-aortic balloon control rather than conventional cross-clamping. Dacron tape was used to anchor the aortic wall in the groove of the ring and hemostasis was invariably secure. The iliac anastomoses could be accomplished with the sutureless technique in only 42% of the cases, the remaining anastomoses being completed in the conventional fashion. Major difficulties were encountered with associated iliac aneurysms and occlusive disease. Eight postoperative deaths occurred, all in the rupture group. The mean operating time was 134 minutes, with mean blood loss of 3500 ml. Autopsies conducted in six of the eight patients revealed well-secured grafts with no evidence of early technical failure or graft-related complications. The obvious concern for avascular necrosis of the aortic wall under the securing tape has been addressed by the authors who note that their preliminary animal experiments failed to show any related complications over a relatively short 6-month term. They also note that conventional anastomoses can result in similar extensive areas of ischemic necrosis.

Tbowm S. Riles, M.D. New York Univemiq Medical

Center

Rupture of splanchnic artery aneurysms Salo JA, Salmenkivi K, Tenhumen A, et al. World 1986;10:123-7.

J Surg

Splanchnic artery aneurysms are unusual. Intra-abdominal hemorrhage is a frequent symptom (22%) associated with a high mortality rate (20°h to 75%). Six patients were treated for acute rupture of splanchnic artery aneurysm at Helsinki University Central Hospital between 1964 and 1984. This series included aneurysms of splenic artery (three patients), hepatic artery (two patients), and a superior mesenteric branch artery (one patient). Two of three splenic artery aneurysms occurred in female patients. One