Veterinary Surgery 28:83-90, 1999 Evaluation of a Technique to Occlude the Internal Carotid Artery of Horses HOYT S. CHERAMIE, DVM, R. SCOTT PLEASANT, DVM, MS, Diplomate ACVS, JOHN L. ROBERTSON, VMD, PhD, H. DAVID MOLL, DVM, MS, Diplomate ACVS, COLIN B. CARRIG, BVSc, PhD, Diplomate ACVR, DAVID E. FREEMAN, MVB, MRCVS, PhD, Diplomate ACVS, and MARY E. JENSEN, MD Objective—To evaluate an occlusion technique for the internal carotid artery of horses using an intravascular, detachable, self-sealing, latex balloon distally and ligatures proximally. Study Design—Experimental study. Animals—Six healthy adult horses. Methods—In each horse, the left internal carotid artery was occluded by placement of an intravascular, detachable, self-sealing, latex balloon distally and two ligatures proximally. Radio- graphs were taken on days 2, 5, 10, and 30 after surgery to evaluate balloon inflation and position. Endoscopic examination of the left guttural pouch was performed 10 days after surgery to evaluate the integrity of the internal carotid artery and surrounding tissues. At 30 days, the left and right, common, internal, and external carotid arteries were examined grossly and then processed for histologic evaluation. Results—Immediate and long-term occlusion of the left internal carotid artery was achieved in all horses. The surgical procedure was technically straightforward and no intraoperative or postoperative complications were encountered. The balloons remained inflated and in their original position throughout the study. Maturing to mature, organized thrombi were present in the left internal carotid artery in all horses at 30 days. The cerebral arterial circle and common carotid artery were patent at their junctions with the internal carotid artery in all horses. Conclusions—Use of an intravascular, detachable, self-sealing, latex balloon distally and ligatures proximally is an effective technique for occluding the internal carotid artery of horses. Clinical Relevance—This technique may be useful for prevention of fatal hemorrhage in horses with lesions of the internal carotid artery. ©Copyright 1999 by The American College of Veterinary Surgeons F UNGAL EROSION of the internal carotid artery and accompanying hemorrhage is common in horses with guttural pouch mycosis. 1-3 Because of the high mortality associated with this hemorrhage, it is recommended that the artery be occluded as soon as possible after the problem is recognized. Ligation of the internal carotid artery at its origin (proximal to the mycotic lesion) can be used to reduce the risk of hemorrhage. 4-7 Although successful in most cases, severe and fatal hemorrhage has occurred after this procedure, attributed to retrograde flow from the cerebral arterial circle. 4-7 Success with this technique relies on thrombosis distal to the point of ligation at some time after surgery. Consequently, horses treated From the Departments of Large Animal Clinical Sciences, Biomedical Sciences and Pathobiology, and Small Animal Clinical Sciences, Virginia-Maryland Regional College Veterinary Medicine, Virginia Tech, Blacksburg, VA; the Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois, Urbana, IL; and the Department of Radiology, University of Virginia Health Sciences Center, Charlottesville, VA. Supported by grants from the Virginia Veterinary Medical Association and the United States Department of Agriculture, Animal Health and Disease Fund. Presented at the 7th Annual American College of Veterinary Surgeons Symposium, Orlando, FL, October, 1997. No reprints available. ©Copyright 1999 by The American College of Veterinary Surgeons 0161-3499/99/2802-0001$3.00/0 83