Carotid endarterectomy: operative risks, recurrent stenosis, and long-term stroke rates in a modern series

To determine whether carotid endarterectomy (CEA) safely and effectively maintained a durable reduction in stroke complications over an extended period, we reviewed our data on 478 consecutive patients who underwent 544 CEA's since 1976. Follow-up was complete in 83% of patients (mean 44 months). There were 7 early deaths (1.3%), only 1 stroke related (0.2%). Perioperative stroke rates (overall 2.9%) varied according to operative indications: asymptomatic, 1.4%; transient ischemic attacks (TIA)/amaurosis fugax (AF), 1.3%; nonhemispheric symptoms (NH), 4.9%; and prior stroke (CVA), 7.1%. Five and 10-year stroke-free rates were 96% and 92% in the asymptomatic group, 93% and 87% in the TIA/AF group, 92% and 92% in the NH group, and 80% and 73% in the CVA group. Late ipsilateral strokes occurred infrequently (8 patients, 1.7%). Late deaths were primarily cardiac related (51.3%). Stroke-free rates were significantly (p less than 0.0001) greater than stroke-free survival rates, confirming a non-stroke related cause for late death. Restenoses greater than 50% according to duplex scanning developed in 13%, most (67%) within 2 years after CEA. Most of these (77%) were asymptomatic, and only 0.3% (1 patient) presented with a permanent neurologic deficit. The results of carotid endarterectomy are superior to those of optimal medical management in symptomatic and asymptomatic patients in terms of long-term stroke prevention. When low perioperative stroke mortality/morbidity rates are achieved, carotid endarterectomy is justified for treatment of patients with carotid bifurcation disease.

Identifying total carotid occlusion with colour flow duplex scanning

A major limitation of conventional duplex scanning is its inability reliably to differentiate severe stenosis from total occlusion of the internal carotid artery (ICA). Colour flow duplex scanning (CFS) facilitates the identification of internal and external carotid arteries, enables simultaneous evaluation of flow in multiple vessels in longitudinal and transverse views, and allows more accurate assessment of very low Doppler-shift frequencies with new "slow-flow" software technology. From July 1987 to January 1991, 9731 ICAs (4866 patients) were evaluated with CFS. Arteriography was performed in 483 of these patients (959 ICAs), and the results of the two studies were compared. Colour flow scanning was highly accurate in differentiating total occlusion from carotid stenosis. Eighty-two of 87 totally occluded ICAs were detected (sensitivity 94%) and 873 of 878 patient arteries were properly identified (specificity 99%). Positive and negative predictive values were 93 and 99%, respectively. False positive results (n = 6) were due to interpreter error (n = 4) and poor scanning technique (n = 2). All false negative results (n = 5) were the result of interpreter error. During the last 24 months of the study, no false positive or false negative results were detected, giving an accuracy of 100%. We conclude that CFS offers distinct advantages in the diagnosis of carotid occlusion, thereby overcoming the limitations of conventional duplex scanning in distinguishing total occlusion of the ICA from less severe disease, and is the method of choice for evaluating the carotid bifurcation.

Color-flow duplex scanning for the surveillance and diagnosis of acute deep venous thrombosis

Compared with conventional duplex imaging, color-flow scanning facilitates the identification of veins (especially below the knee), decreases the need to assess Doppler flow patterns and venous compressibility, and allows veins to be surveyed longitudinally. These advantages translate into a less demanding and time-consuming examination. This study was designed to determine the accuracy of color-flow scanning for detecting acute deep venous thrombosis in patients in whom the diagnosis is clinically suspected and in asymptomatic patients at high risk for developing postoperative deep venous thrombosis. The diagnostic group included 77 limbs of 75 patients, and the surveillance group included 190 limbs of 99 patients undergoing total hip or knee replacement. All patients were prospectively examined with color-flow scanning and phlebography. In the diagnostic group, the incidence of thrombi in below-knee veins (47%) was approximately equal to that in above-knee veins (43%); but in the surveillance group, the incidence of thrombi in below-knee veins (41%) far exceeded that in veins above the-knee (3%). Nonocclusive clots and clots isolated to a single venous segment were more common in the surveillance group. In symptomatic patients, color-flow scanning was 100% sensitive and 98% specific above the knee and 94% sensitive and 75% specific below the knee. In the surveillance group, color-flow scanning was significantly (p less than 0.001) less sensitive (55%) for detecting thrombi, 93% of which were confined to the tibioperoneal veins. Negative predictive values were 100% and 88% for the diagnostic and surveillance limbs, respectively. Positive predictive values were 80% for the diagnostic limbs and 89% for the surveillance limbs. Color-flow scanning effectively excludes above-knee deep venous thrombosis in symptomatic patients and asymptomatic high-risk patients and predicts the presence of above-knee thrombi in patients in the diagnostic group with reasonable accuracy (97%). We conclude that color-flow scanning is as accurate as conventional duplex imaging and, because of its advantages, is the noninvasive method of choice for evaluating patients with suspected deep venous thrombosis. Its role in the surveillance of patients at high risk remains to be determined and awaits further clinical evaluation.

Does color-flow imaging improve the accuracy of duplex carotid evaluation?

To determine whether color-flow imaging enhances the accuracy of noninvasive carotid evaluation, the results of carotid duplex examinations from two laboratories, one with color-flow and the other with standard duplex imaging were compared. The techniques used by both laboratories were identical. All studies were interpreted by one of the authors, using the same criteria. From October 1988 through December 1989, 307 internal carotid arteries were evaluated with both color-flow imaging and standard angiography; and 206 underwent routine duplex scanning and angiography. Perfect agreement between test and angiographic results was significantly better with color-flow (86.6%) than with conventional duplex scanning (79.6%), p = 0.034 (t test for independent samples). Significantly fewer vessels were over classified by one category with color-flow (8.5%) than with routine duplex scanning (16.5%), p = 0.006. However, no difference was found in the number under-classified by one category (4.5% vs 3.4%), p = 0.5. Although these data support the accuracy of both modalities, there appears to be a trend toward improved results with the newer method. We attribute this to more precise placement of the pulsed Doppler sample volume afforded by the color-flow image.

Infrapopliteal bypass for severe ischemia: comparison of autogenous vein, composite, and prosthetic grafts

Results of 253 consecutive bypass grafts to infrapopliteal arteries were reviewed. Most (92%) were placed for rest pain (103) or tissue loss (130). Autogenous veins were used in 175 (69%) cases, composite vein-prosthetic grafts were used in 45 (18%), and prosthetic grafts alone were used in 33 (13%). Follow-up ranged from 0 to 101 months (mean, 19 months); 37 grafts (15%) were lost to follow-up. The operative mortality rate was 4%, and 5-year patient survival rate was 44%. Limb salvage was 82% at 5 years. The 5-year patency of vein grafts (63%) exceeded that of both composite (28%) and prosthetic (7%) grafts (p = 0.005 and p = 0.00007, respectively); but the patency of composite and prosthetic grafts did not differ significantly (p = 0.29). The patency of reversed vein (59%) and in situ vein grafts (74%) was not significantly different at 5 years (p = 0.34). Patency was also not affected by the site of the proximal or distal anastomoses or diabetes. The major determinant of long-term patency in infrapopliteal reconstructions continues to be graft material. Composite grafts offered no clear advantage over prosthetic grafts, and both should be used only when there is no other alternative to amputation.

Initial experience with color-flow duplex scanning of infrainguinal bypass grafts

Seventy-eight infrainguinal grafts were evaluated by means of color-flow duplex imaging to demonstrate its utility in the routine surveillance of leg grafts as well as in the evaluation of grafts in which a problem is already suspected. Stenoses were identified in 15 (20%) of 76 grafts evaluated for screening purposes. Seven of these had confirmatory arteriograms, and five were revised. The remaining eight grafts with suspected stenoses were followed without angiography, and four (50%) subsequently failed. Only two (3.3%) of 61 grafts with normal scan outcomes have thrombosed. Fistulas were identified in 12 (37%) of 32 in situ grafts evaluated. Nine grafts with previously suspected problems based on decreased ankle-brachial indexes were scanned, and an explanation was found, confirmed by angiogram, and corrected in six. Detection of unsuspected stenoses in five grafts requiring revision and four grafts that later thrombosed without revision, as well as identification of fistulas in 37% of in situ grafts, confirms the importance of color-flow imaging as a screening tool.

Contralateral internal carotid artery stenosis or occlusion: pitfall of correct ipsilateral classification--a study performed with color-flow imaging

The records of 183 patients who had undergone color-flow imaging of the extracranial carotid arteries and subsequent bilateral cerebral arteriography were reviewed to determine whether contralateral carotid arterial disease adversely affects the accuracy of duplex scanning by increasing the velocity of flow in the ipsilateral artery. In 83 arteries the contralateral internal carotid artery had a diameter reduction greater than or equal to 80%; in the remaining 283, the contralateral artery was less severely diseased. Noninvasive findings correlated less well with arteriography in the group with contralateral disease (k = 0.69 +/- 0.06) than in the group with less severe contralateral stenosis (k = 0.78 +/- 0.03), and the incidence of false-positive errors was significantly (p = 0.02) higher (18% vs 7%). For all categories of ipsilateral stenosis, the mean peak systolic and end-diastolic velocities were elevated in the group with severe contralateral disease. This effect was most evident in the 50% to 79% diameter reduction category, especially in reference to the end-diastolic velocity (p = 0.2). However, the data correlating velocity with diameter reduction were widely scattered, indicating that the effect of contralateral disease is inconsistent. We conclude that severe disease of the contralateral carotid artery can lead to overreading ipsilateral disease and that velocity determinations should be interpreted cautiously under such circumstances.

Noninvasive assessment of lower extremity arterial disease

Although angiography is the accepted "gold standard" for demonstrating the presence of arterial occlusive disease, it is less accurate for grading the associated hemodynamic consequences and is prohibitively invasive and expensive to be used as a first-line investigation. Currently available noninvasive tests allow not only for the detection of perfusion abnormalities, but for an appreciation of their severity as well as their likely location. This information is invaluable for predicting the need for revascularization, guiding the choice of reconstructive procedure, and predicting the likelihood of healing of amputation wounds and ischemic lesions. Although some obstructive lesions are easily detected, others require more in-depth testing to reveal and quantify. Consequently, a thorough understanding of available noninvasive diagnostic modalities, including both their capabilities as well as their pitfalls, is paramount to the effective practice of vascular surgery.

Retroperitoneal approach to the Warren shunt

The Warren shunt, despite its recognized attributes, has several major obstacles to gaining widespread acceptance in the surgical community. These include its technical difficulty and the increased incidence of postoperative ascites. We have begun using a retroperitoneal approach for the performance of this procedure, which we believe is technically easier and may lessen postoperative ascites. In addition, blood loss, the need for ventilatory support and intensive care, and the occurrence of postoperative ileus have all been reduced in our experience. Herein, we have reported the details of this approach and discussed its major advantages over the classic transperitoneal approach to the distal splenorenal shunt.

Buttock claudication from isolated bilateral internal iliac arterial stenoses

An unusual case is reported of severe buttock claudication in a woman with normal ankle systolic pressures after exercise, for which the cause was eventually found to be isolated bilateral hypogastric arterial stenosis. Although a normal ankle pressure response to exercise usually rules out vascular obstruction in patients with symptoms suggestive of intermittent claudication, the diagnosis of isolated hypogastric arterial disease should be entertained when a neurogenic or orthopedic explanation can be excluded.

A simple technique for improving the cosmesis of excision of a melanoma and skin grafting

A simple technique is described to reduce the size of the skin defect resulting from excision of a malignant melanoma. An added advantage of this technique is the smoother contour at the native skin to skin graft junction. These effects are achieved by apposing the skin edge to the muscle using a simple pursestring suture technique which simultaneously draws the wound edges centrally. The resultant smaller area to be grafted, smaller donor site, better graft survival and superior cosmesis represent an improvement over conventional skin grafting techniques.

Abdominal aortic aneurysm causing duodenal and ureteric obstruction

We report a unique case of an abdominal aortic aneurysm complicated by both duodenal and ureteric obstruction and review the literature on these conditions. Duodenal obstruction is a consequence of compression of the duodenum in its fixed retroperitoneal course between the aneurysmal aorta and the superior mesenteric artery. Treatment should be based on replacement of the aneurysm as gastrointestinal bypass alone does not resolve the risk of aneurysm rupture. Ureteric obstruction is related to encasement of the ureters in an inflammatory perianeurysmal fibrosis of unresolved etiology rather than secondary to aneurysm compression. Although urinary tract symptoms are often seen with aortic aneurysms, they tend to be nonspecific and are often overlooked. As many as 71% of patients with abdominal aortic aneurysms may have radiologic evidence of ureteric involvement. Although aneurysm replacement alone may resolve the perianeurysmal fibrosis with resultant relief of ureteric obstruction, most authors advise simultaneous ureterolysis. Aortic aneurysm should be considered as a possible cause of duodenal or ureteral obstruction in the elderly, especially in the presence of a pulsatile abdominal mass.