Carotid thromboendarterectomy for recent total occlusion of the internal carotid artery.

BACKGROUND: The efficacy of emergency carotid thromboendarterectomy (CTEA) for acute internal carotid artery (ICA) thrombosis has been questioned. We evaluated the use of CTEA in patients with recent ICA occlusion. METHODS: From August 1989 to December 1999 patients who underwent urgent CTEA for recent ICA thrombosis were retrospectively evaluated. Patient data analyzed included age, sex, comorbid risk factors, diagnostic evaluation, operative procedure, and long-term follow-up with clinical assessment and carotid duplex scan. Neurologic status was evaluated with the Modified Rankin Scale (MRS) before the operation, immediately after the operation, and at 3- to 6-months' follow-up. RESULTS: Twenty-nine patients underwent emergency ipsilateral CTEA for acute ICA thrombosis over the last 10 years. The average age of the patients was 69.9 +/- 1.7 years, and 66% were men. Patient risk factors included diabetes (7 [24%]), hypertension (21 [72%]), coronary artery disease (8 [29%]), and history of tobacco abuse (20 [69%]). Presenting symptoms included cerebrovascular accident (7 [24%]), transient ischemic attack (nonamaurosis) (10 [34%]), crescendo transient ischemic attack (7 [24%]), stroke in evolution (2 [7%]), and amaurosis fugax (3 [10%]). Diagnostic evaluation included computed tomographic scan (29 [100%]), magnetic resonance imaging/magnetic resonance angiography (4 [14%]), duplex scan evaluation of the carotid arteries (23 [79%]), and cerebral angiography (18 [64%]). Antegrade flow in the ICA was successfully established in 24 (83%) of 29 patients and confirmed with intraoperative angiography or duplex sonography. Postoperative morbidity included 2 hematomas (7%), 4 transient cranial nerve deficits (14%), and 1 conversion to hemorrhagic stroke (3.6%), which resulted in the only death (3.6%). MRS scores averaged 3.4 +/- 0.2 preoperatively. Follow-up averaging 74.1 +/- 21 months (range, 3-140 months) was obtained in 27 (93%) patients. Improvement or deterioration was defined as a change in MRS +/- 1. Immediately postoperatively, 14 (48%) patients were improved, 2 (7%) deteriorated, and 13 (45%) had no change. At 3 to 6 months, 20 (74%) of 27 patients were improved, seven (26%) had no change, and none deteriorated. Of patients with successful CTEA, 23 (96%) of 24 had a patent ICA on follow-up duplex scan evaluation, and there was no evidence of recurrent ipsilateral neurologic events at an average of 49 months. CONCLUSION: These data support an aggressive early surgical intervention for acute ICA thrombosis in carefully selected patients. In the previous decade we reported a 46% success rate for establishing antegrade flow in the ICA long term. Data from this decade show a 79% (P =.0114) success rate for establishing antegrade flow long term in all patients undergoing emergency CTEA. New and improved imaging modalities have allowed better patient selection, resulting in improved outcomes.

Effects of completion angiography on the outcome of carotid endarterectomy.

The carotid endarterectomy results of a single surgeon were analyzed over an 8-year period to determine how routine completion angiography affected endarterectomy outcome. Completion angiography was performed in 80% of cases. A total of 145 patients (86%) were symptomatic while 23 (14%) were symptom-free. Of 131 completion angiographies performed, 94 were interpreted as normal and 37 abnormal. The arteries were reopened in 23 patients with abnormal results. In the 14 patients with abnormal angiograms who were not reopened, two showed no flow into the internal carotid artery and the vessels were ligated. The remaining 12 patients had abnormalities in the external carotid artery or normal Doppler signals along the common carotid artery and internal carotid artery segments. Among the 37 patients with abnormal angiograms, arteries were re-explored in four; there were no neurologic complications. In the entire group, there were three mortalities, one stroke, one transient ischemic attack, two wound complications, four myocardial infarctions, two occurrences of cerebral edema, two pneumonias and nine transient local nerve injuries. Completion angiography has allowed an improved technique while also enhancing the ability to identify technical problems during surgery without increasing morbidity. These results support the use of intraoperative completion angiography to evaluate carotid endarterectomy sites.

Venous and arterial anomalies of the lower extremities diagnosed by duplex scanning.

The complex embryologic development of the vascular system often results in a myriad of clinically relevant anomalies. It has been stated that the classic anatomic venous pattern in the lower extremity is found in only 16 percent of patients. Previous studies on this topic are limited to isolated venous dissections or phlebography that lack complete anatomic detail. The recent introduction of high resolution duplex scanners for the assessment of veins of the lower extremity provides a unique opportunity to determine the incidence of anatomic variation. The current prospective study was done to identify venous or arterial anomalies apparent during routine duplex scanning of the lower extremity performed to rule out deep venous thrombosis (DVT). Limbs that had evidence of acute or chronic extensive DVT were excluded. Of 1,600 consecutive extremity scans, 946 extremities (59 percent) had no evidence of DVT. Of these, there were 43 patients with 64 anomalies in 57 extremities. The mean age of the group was 53.4 years. There were 24 women (55.8 percent) and 19 men (44.2 percent). There were 59 (92.2 percent) venous and five (7.8 percent) arterial anomalies. Duplication of the superficial femoral vein was the most common anomaly noted. Duplication of the deep femoral and popliteal vein was also noted. Unilateral anomalies were more common than bilateral anomalies, namely 67.4 versus 32.6 percent, respectively. Pain and swelling, common complaints in the patients with an anomaly, were noted in 71.4 and 45.7 percent, respectively. The frequency of deep venous anomalies of the lower extremities may be less than previously reported. Knowledge concerning the incidence and distribution of venous anomalies may lead to improved assessment and treatment of venous disease.

Operative management of greater saphenous thrombophlebitis involving the saphenofemoral junction.

Forty-three consecutive patients with greater saphenous vein (GSV) thrombosis extending to the saphenofemoral junction (SFJ) were treated. Twenty-three patients had extension of thrombus into the common femoral vein (CFV). Twenty patients had thrombus extending to but not within the CFV. Symptoms, risk factors, and physical examination were not predictive of CFV thrombus extension. When compared with the operative record, duplex scans accurately located the extent of the thrombosis 100% of the time. Forty-one surgical procedures were performed. No patients had pulmonary emboli during the procedures. Thirty-seven patients were treated as outpatients or were discharged within 3 days of their surgical procedures. The two patients who did not undergo operative procedures in this series had complete occlusion of the CFV with extension into the external iliac vein. Thrombus within 3 cm of the SFJ is an indication for surgical intervention. Disconnection of the GSV from the CFV prevents extension of the thrombus, and a limited CFV thrombectomy can be performed when necessary. This is considerably more cost-effective than treatment with anticoagulation.

Superficial thrombophlebitis diagnosed by duplex scanning.

Since July 1982, this noninvasive vascular laboratory has performed 12,856 lower extermity venous duplex examinations. All cases of acute venous thrombosis have been categorized and entered into a computer data base. One thousand four hundred twelve examinations were positive for acute venous thrombosis. This report analyzes the laboratory's entire experience with superficial thrombophlebitis (SVT). One hundred eighty-six patients were diagnosed by duplex scanning to have SVT. Women outnumbered men 99 to 87. They were slightly older (average age 58.4 +/- 16.2 years) compared with the men (53.8 +/- 14.2 years). Men were more likely to have a complicated course of SVT (40% vs 22%; p less than 0.01). Complications included either radiographically documented pulmonary embolism or deep venous involvement. Fifty-seven (31%) patients had at least one complication of SVT. A series of predisposing factors was analyzed and six factors were associated with an increased risk of complications. They are bilateral SVT (p less than 0.01), age greater than 60 years (p less than 0.01), male sex (p less than 0.01), history of deep venous thrombosis (p less than 0.01), bed rest (p less than 0.02), and presence of infection (p less than 0.02). Location of thrombus within the greater saphenous vein (35%) was most likely to be associated with complications. Isolated varicosities (8%) were least likely to be associated with complications. Duplex scanning identifies a significant number of complications of patients with SVT and should be obtained in cases of saphenous vein involvement or in the presence of associated risk factors.

Upper extremity venous thrombosis diagnosed by duplex scanning.

The incidence of axillary-subclavian venous thrombosis continues to rise, while reports of noninvasive methods to diagnose this condition have been sparse. A review of the records of 693 consecutive upper extremity duplex scans was performed, and a diagnosis of acute venous thrombosis was made in 123 of these patients. Of these, 85 involved the axillary or subclavian vein. Use of a central venous catheter was the most common risk factor for axillary-subclavian venous thrombosis. Within this group, 8% had a pulmonary embolism, of which 25% were fatal. Follow-up of patients with axillary-subclavian venous thrombosis at a mean of 2 years revealed that 49% of these patients had died. Of the remaining patients, more than one third had evidence of the post-thrombotic syndrome. Duplex scanning of the venous system provides a safe, reliable, and repeatable method of evaluating and following patients with suspected venous thrombosis of the upper extremity.

Comparison of autogenous fistula versus expanded polytetrafluoroethylene graft fistula for angioaccess in hemodialysis.

A hundred patients with RCAV fistulas we compared with 100 patients with expanded PTFE fistulas created during the same time period. The fistulas were analyzed to compare early and late thrombosis, life table patency, infection rate, venous hypertension, and vascular steal. There was a significantly greater incidence of early thrombosis in the RCAV fistula group. Late thrombosis was seen with equal frequency in both groups. Thirty month patency by life table analysis favored the RCAV group to a significant degree, whereas infections, pseudoaneurysms, venous hypertension, and vascular steal were all more common in the expanded PTFE group. The RCAV fistula remains the ideal form of access but it is less frequently available for women and patients with peripheral vascular disease. Utilization of the expanded PTFE loop fistula requires closer observation and maintenance to keep it functional. Improved methods of patient selection for RCAV fistula using ultrasonographic imaging may allow for increased use of this form of access. Improvement in early patency in RCAV fistulas will magnify the superiority of RCAV fistulas in comparison to expanded PTFE fistulas, however, a prolonged period of venous maturation may be necessary to improve early function.

Ischemic colitis following repair of ruptured abdominal aortic aneurysm.

Seven patients--six of whom died--underwent surgical repair of a ruptured abdominal aortic aneurysm and developed postoperative ischemic colitis. All patients were male, with a mean age of 62 years. Resection of the necrotic colon with a colostomy was necessary within the first postoperative week for the six patients who did not survive and on the 40th postoperative day for the patient who lived. The colon is vulnerable to ischemic necrosis after an aortic rupture because of tissue hypoperfusion and impaired mesenteric artery circulation due to preexistent occlusive disease. In high-risk patients, fiberoptic colonoscopy and examination of stool for occult blood, with immediate abdominal exploration, if necessary, are important in the early postoperative period. Symptoms may develop insidiously when tissue damage is limited to the mucosal layer, but delay in resecting the ischemic segment allows for the extension of necrosis, with perforation.

Endothelial cell seeding of a new PTFE vascular prosthesis.

Previous attempts to line polytetrafluoroethylene (PTFE) prostheses with enzymatically derived endothelial cells have not been as successful as similar work with Dacron grafts because of the failure of such prostheses to develop a satisfactory subendothelium. This article reports our experience with a new, highly porous, unreinforced PTFE prosthesis that appears to circumvent this problem. Segments (4 mm I.D., 10 cm in length) of this new graft were implanted in 41 mongrel dogs as carotid interposition grafts. One graft in each dog was seeded with the dog's own endothelial cells, whereas the contralateral graft was treated in an identical fashion except for the inclusion of endothelium. After a mean period of 7 weeks of implantation, the grafts were harvested, their patencies were noted, the thrombus-free area of their luminal surface was calculated with computerized quantitative planimetry, and graft segments were submitted for scanning and transmission electron microscopy. In seven dogs the luminal surface was scraped from each graft and measured quantitatively. Although seeded grafts failed to show a statistically significant increase in patency during the short course of this experiment, a trend in that direction was quite striking. Furthermore, seeded grafts had a significant increase in thrombus-free area on their luminal surface as well as a significant reduction in the volume of luminal thrombus. Histologically, seeded grafts developed a substantial 75 to 100 microns cellular subendothelium beneath a confluent endothelial lining. No endothelial lining was noted in control grafts. We believe that the superior handling characteristics of this new prosthesis and its ability to develop a substantial subendothelium with a confluent endothelial lining suggest potential future applications and warrant further investigation.

Efficacy of low-dose streptokinase in acute arterial occlusion and graft thrombosis.

In a review of 35 patients undergoing local thrombolysis using selective infusion of low-dose streptokinase, the overall success rate was 43%. Streptokinase appears to be most effective in occlusion of native arteries, in high-flow segments, and in autogenous saphenous vein grafts. Local streptokinase was least effective in occluded prosthetic grafts in the femoropopliteal segment (19% success). Distal embolization and progression of thrombosis of the distal arterial tree may occur while the patient is undergoing local thrombolysis and may result in limb loss. Hence, local thrombolysis is not recommended when surgical treatment is an alternative. Despite the low dose, systemic fibrinolytic effects and hemorrhagic complications were common occurrences; hence, routine hematologic monitoring is mandatory in patients undergoing lytic therapy with local infusion of streptokinase.

Surgical therapy for recent total occlusion of the internal carotid artery.

From January 1980 until May 1983, 24 patients had surgical exploration of the carotid bifurcation for suspected recent total occlusion of the internal carotid artery (ICA). All patients had recent onset of neurologic symptoms related to the ipsilateral cerebral hemisphere. Selective carotid angiography determined preoperative total occlusion of the ICA. Because surgery failed to reopen the ICA in nine patients, they had endarterectomy of the external carotid artery. Fifteen patients had initially successful thromboendarterectomy of the ICA. Prior to patient dismissal, patency was documented by B-mode ultrasound or digital subtraction angiography (DSA). All 15 patients had another B-mode ultrasound scan or DSA at least 45 days after thromboendarterectomy. On reexamination four ICAs were reoccluded, but only one patient became symptomatic. There were no operative deaths and no increase in preoperative neurologic deficits. The natural history of patients with total occlusion of the ICA is variable. The most important factor influencing a therapeutic decision is the patient's neurologic status. This study supports an aggressive, early surgical intervention for recent total occlusion in carefully selected patients.

Effects of aspirin and dipyridamole on expanded polytetrafluoroethylene graft patency.

A randomized, double-blind clinical trial was designed to assess the effect of aspirin (ASA) alone or in combination with dipyridamole (DIP) on the patency rates of expanded PTFE grafts placed in the infrainguinal position. Forty-nine patients were randomized into three groups who received three times daily either two placebos (17 patients), 325 mg ASA and placebo (16 patients), or 325 mg ASA and 75 mg DIP (16 patients). The patients were seen at 3-month intervals for 1 year, and coded medication bottles were dispensed and returned pills counted to assess patient compliance. Treatment failure was defined as the first graft occlusion. The data were analyzed using the Breslow statistic for progressively censored survival type data. The 1-year cumulative patency rate for the entire series was 59%. The rates for above-knee grafts in the ASA group (100%) and the ASA/DIP group (100%) were significantly higher than the rates for the placebo group (50%) (P = 0.05). The 1-year cumulative patency rates for patients with below-knee grafts were not statistically different among the groups, although the patients who received ASA alone had a higher rate than did the other two groups (65% versus 21% for placebo and 19% for ASA/DIP). There were fewer occlusions in the above-knee grafts as compared to below-knee grafts in all groups, but the differences were statistically significant only in the ASA/DIP group. There were no statistical differences between the two active treatment groups.

Doppler evaluation of the pedal arch.

The association of a patent pedal arch with early distal bypass patency has recently been emphasized. Unfortunately, in many patients information about the pedal arch can only be obtained with intraoperative angiography. An 8 mHz Doppler probe was used to noninvasively evaluate the pedal arch in 62 patients with various degrees of vascular disease. The probe was placed in the first metatarsal space, and the presence of a Doppler signal was taken as evidence of a patent pedal arch. Digital pressure was then applied over each tibial artery at the malleolar level to determine each vessel's communication with the pedal arch. Fifty-two patients were found to have patent pedal arches, while 10 did not. Preoperative hyperemic angiography or intraoperative arteriography was used to study the pedal arch in 22 of these patients. The arteriographic and Doppler findings were the same in 21 of 22 cases (96 percent accuracy). In the one case in which the results conflicted, the Doppler examination also gave information about which calf vessel contributed the most flow to the pedal arch. Preoperative Doppler evaluation of the foot combined with arteriography allows better selection of patients for distal bypass grafts.

Predicted hyperemic angiography: a technique of distal arteriography in the severely ischemic leg.

A technique of distal arteriography in the severely ischemic leg has been developed by modifying hyperemic angiography. The postischemic hyperemic response can be measured for a given patient and the time fo maximum glow predicted. A study of 35 patients with severe ischemia has shown the maximum hyperemic response time (MHRT) to vary greatly among patients. Knowing the specific MHRT in advance has enabled us to inject contrast during maximum flow periods. The resulting predicted hyperemic angiograms provided visualization of the pedal arch in four extremities not visualized by conventional angiography. Predicted hyperemic angiography appears to provide a means of evaluating calf and pedal circulations in severely ischemic legs prior to surgery.

Comparison of platelet adherence and aggregation in modified human umbilical vein and autogenous vein grafts.

The use of glutaraldehyde-tanned human umbilical vein as a vascular conduit has recently become popular. In previous studies in our laboratory, neointimal fibrous hyperplasia was responsible for poor long-term patency of this material in a canine model. The present study was undertaken to compare the platelet-adhering characteristics of autogenous vein and modified human umbilical vein. After platelets were labelled with chromium-51, 10 mongrel dogs underwent bilateral end-to-side femoral artery bypass grafts. Human umbilical vein and autogenous jugular vein were placed in opposing groins of each dog. Two hours after graft implantation, the animals were killed and the grafts retrieved along with 1 cm of the host artery at each anastomosis. These specimens and an aliquot of blood were placed in a scintillation counter and radioactivity levels were determined. The human umbilical vein had significantly more platelet adherence than the autogenous veins as determined by counts per gram per 10 minutes. The handling characteristics of human umbilical vein were also suboptimal. Separation of the graft layers was occasionally observed, sometimes resulting in intramural hematomas and graft dissection. The previously reported poor performance of human umbilical vein in the canine model is most likely a result of its platelet-adhering surface and poor handling characteristics.

Goretex and autogenous vein in the canine model.

Thirty Goretex grafts of 6 mm internal diameter, 30 mu fibril length, 30 mg/cc density and 0.5 mm wall thickness were placed as end-to-side bypass grafts in canine femoral arteries. Handling characteristics, patency and healing properties were compared with autogenous jugular veins which were anastomosed into the opposing femoral arteries. Autogenous veins were easier to anastomose and they showed a patency rate of 87% over a 16 week observation period. The Goretex grafts had a 50% patency rate during the same period. Goretex grafts failed because of technical errors (9), graft kinks (5), infection (3) and neointimal fibrous hyperplasia (2). This canine model has previously been used to evaluate all currently available biologic and synthetic vascular grafts. Goretex grafts demonstrated the highest rate of technical failures, but the lowest incidence of neointimal fibrous hyperplasia when compared to other grafts previously tested in this model.