Role of arteriography in the preoperative evaluation of carotid artery disease

Article Abstract:

Carotid endarterectomy is a surgical procedure used to remove the cholesterol-plaque-thickened inner lining of the carotid artery; the carotid arteries provide the main blood supply to the brain. Traditionally, before endarterectomy is performed the patient will undergo arteriography (X-ray study of the artery using contrast dye). This procedure is expensive, is uncomfortable for the patient, and is also a potential source of complications. Duplex scanning is accurate in diagnosing lesions of the carotid artery that affect the blood flow. This is a noninvasive procedure which combines ultrasound and Doppler study; it accurately measures blood flow and provides detail of the vessel wall structure. A study was undertaken to determine how frequently findings on arteriography changed the patient's treatment, and to determine if endarterectomy can be performed without preoperative arteriography. Medical records of 83 patients were reviewed; these patients were candidates for endarterectomy who had duplex scanning performed and then underwent arteriography. Findings on duplex scanning agreed with results of arteriography in 87 percent of cases, or were within one category of the arteriography findings in 98 percent of cases. In 12 cases (13 percent), the findings of arteriography appear to have changed the treatment that the patient received. However, if the duplex scan was technically satisfactory, the findings on the arteriogram did not usually change the patient's treatment. These results indicate that most patients who undergo carotid endarterectomy do not need routine preoperative arteriography. (Consumer Summary produced by Reliance Medical Information, Inc.)

Evaluation, Carotid artery, Carotid arteries, Duplex ultrasonography

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Mechanism of long-term degeneration of arterialized vein grafts

Article Abstract:

Within the first five years, 30 percent of saphenous vein grafts used in femoropopliteal (leg) and aortocoronary (heart) operations fail. This is due to progressive narrowing of the graft. During the first year, the vein grafts thicken and narrow. This is an adaptive response that reduces the stress on the wall of the vein graft to the level of its adjacent artery. The graft wall does not have the elastin layers that permit arteries to respond to changes in systemic pressure. After one year, the grafts may show deposits of lipid (fat), as well as ulceration, calcification and cholesterol clefts. A study was undertaken of rabbit vein grafts to characterize the time at which the atherosclerotic changes in the graft begin to develop. At one year after graft placement, the circumference and thickness of the graft wall was similar to that found at 12 weeks after graft placement. About three months after graft placement, the wall stress had returned to normal arterial levels; this was a result of vein graft wall thickening caused by intimal hyperplasia (thickening of the inner layer of the vein). There were degenerative changes noted at one year. These included increased permeability, hemorrhage within the internal layer (intima) of the vein graft, subendothelial foam cells, and deposits of fibrin (clotting element). These degenerative changes, which may be early beginnings of atherosclerosis (cholesterol plaque formation on the inner layer of the wall), may be caused by increased wall tension or by low shear rates at the wall. (Consumer Summary produced by Reliance Medical Information, Inc.)

Models, Physiological aspects, Veins, Vascular grafts, Venous grafts

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Injuries to the portal triad

Article Abstract:

Deep within the upper right part of the abdomen, near the liver, gallbladder, stomach, right kidney and small intestine, lies the portal triad. The portal triad consists of the portal vein of the liver, the hepatic (liver) artery, and the hepatic and common bile ducts. Injury to this area may threaten these vital structures. A review was undertaken of 21 patients treated at a Level I trauma center for portal triad injury over an 11-year period. Portal triad injuries accounted for only 0.21 percent of all patients treated for multiple trauma during this period. Eight patients had suffered blunt injury as a result of falls, motor vehicle accidents or pedestrian accidents, and 13 patients had gunshot or stab wounds. Injury to the portal triad was never diagnosed prior to surgery. Eleven of 21 patients (52 percent) died, all due to uncontrolled bleeding during surgery. The portal vein was injured in 14 patients, the hepatic artery in seven patients, and the bile duct in four patients (three patients had injury to more than one structure). Ten of the 14 patients (71 percent) with portal vein injury died. The rate of complications requiring additional surgery or drainage procedures was high (80 percent), occurring in 8 of the 10 patients who lived. Portal triad injuries are rare and difficult to diagnose, yet they require prompt treatment. Rapid control of bleeding is the first priority of treatment. (Consumer Summary produced by Reliance Medical Information, Inc.)

Injuries, Bile ducts, Portal vein, Hepatic artery

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