Faculty Bibliography

OBJECTIVE: To determine whether there is an advantage of thoracic over lumbar epidural narcotics for postoperative analgesia in patients undergoing abdominal aortic aneurysm repair. DESIGN: A prospective randomized study. SETTING: Subjects were inpatients at an academic medical center. PARTICIPANTS: Fifty-two patients scheduled for elective abdominal aortic aneurysm repair. INTERVENTIONS: Subjects were randomly assigned to receive lumbar or thoracic epidural narcotics. Group 1 (n = 26) had lumbar, and group 2 (n = 26) had thoracic epidural catheters placed preoperatively. All patients were monitored with pulmonary artery catheters and arterial catheters, and had general endotracheal anesthesia, in addition to epidural anesthesia with 2% lidocaine. All patients received 5 mg of epidural morphine after intubation. Pain scores were monitored hourly for 36 hours using a visual analog scale, and additional narcotics were given, depending on the level of pain. Complications caused by epidural narcotics were recorded. RESULTS: There was no difference between groups as to the daily dose of narcotics or the time between narcotic doses. Hourly pain scores showed significant differences during hours 6, 7, 8, 20, 34, and 36, with pain scores being lower in group 1. There was no difference in the rate of complications between the groups. CONCLUSION: There is no advantage of thoracic over lumbar epidural analgesia using morphine in patients undergoing abdominal aortic aneurysm repair

PURPOSE: Although it has been widely accepted as the evidence supporting prophylactic carotid endarterectomy, aspects of the Asymptomatic Carotid Atherosclerosis Study have left unease among clinicians who must decide which individuals without symptoms should undergo surgery. Additional confusion has been created by the fact that the several large randomized trials investigating the efficacy of carotid endarterectomy have classified and analyzed different categories of carotid stenosis. In an effort to provide more information on the natural history of asymptomatic, moderate carotid artery stenosis (50% to 79%), we have reviewed data on approximately 500 arteries. METHODS: Records of our vascular laboratory from 1990 to 1992 were reviewed. We identified 425 patients with asymptomatic, moderate carotid artery stenosis; 71 patients had bilateral stenoses in this category, resulting in 496 arteries for study. RESULTS: The mean length of follow-up was 38 +/- 18 months. New ipsilateral strokes occurred in 16 (3.8%) patients. New ipsilateral transient ischemic attacks occurred in 25 (5.9%) patients. Documented progression of stenosis occurred in 48 (17%) of the 282 arteries for which a repeat duplex examination was available. Arteries that progressed to > 80% stenosis were significantly more likely to have caused strokes than those that remained in the 50% to 79% range (10.4% vs 2.1%, p < 0.02). Conversely, arteries that remained stable in the degree of stenosis were significantly more likely to have remained asymptomatic than those that progressed (92.7% vs 62.5%, p < 0.001). With life-table analysis the estimated cumulative ipsilateral stroke rate was 0.85% at 1 year, 3.6% at 3 years, and 5.4% at 5 years. The respective estimated cumulative transient ischemic attack rates were 1.9%, 5.5%, and 6.3%. The respective estimated cumulative rates for progression of stenosis were 4.9%, 16.7%, and 26.5%. Life-table comparison of ipsilateral stroke revealed a significantly higher cumulative rate among arteries that progressed in the degree of stenosis than among those that remained stable (p < 0.001). CONCLUSIONS: Based on the low rate of permanent neurologic events in these cases, prophylactic carotid endarterectomy for the asymptomatic, moderately stenotic internal carotid artery cannot currently be recommended. The only factor that appears to predict increased risk for future stroke is progression of stenosis. Careful follow-up with serial repeat duplex examinations must be performed in these patients. Until there are widely accepted duplex parameters that can provide all clinicians with accurate identification of arteries with narrowing corresponding to 60% stenosis as defined by the Asymptomatic Carotid Atherosclerosis Study, all surgeons will need to be aware of specifically how their noninvasive laboratories are deriving their results. For the many laboratories that continue to use the University of Washington criteria, 80% should remain the level above which prophylactic carotid endarterectomy is warranted

Patients who have sustained a preoperative stroke are at increased risk for perioperative stroke after carotid endarterectomy. At our institution this risk was recently shown to be increased two-to threefold. The purpose of this study was to investigate the reasons for the increased surgical risk in these patients. Records of 606 patients undergoing 704 consecutive carotid endarterectomies from 1988 through 1993 were reviewed. Patients who suffered preoperative strokes (n = 183) were compared to those who were either asymptomatic or experienced only transient ischemic attacks (TIAs) preoperatively (n = 423). Of the 183 patients who had suffered preoperative strokes, eight patients who experienced perioperative strokes after endarterectomy were compared with 175 who successfully underwent surgery. Patients with a prior stroke had an increased perioperative stroke rate (4.4% versus 1.2%, p = 0.01). They had a significantly higher incidence of hypertension (62.6% versus 47.9%, p < 0.001), cardiac disease (54.7% versus 40.7%, p = 0.001), and positive smoking history (52% versus 40.6%, p = 0.01) than did the asymptomatic/TIA patients. The presence of contralateral total occlusion was also significantly increased (22% versus 10.3%, p < 0.001). Although not statistically significant due to the overall small number of patients who sustained perioperative strokes, the preoperative stroke patients who sustained perioperative strokes had a higher incidence of hypertension (87.5% versus 61.5%) and contralateral total occlusion (37.5% versus 21.3%) than did those who successfully underwent surgery. Patients with both a prior stroke and contralateral total occlusion had a 7.5% perioperative stroke rate. Patients with both a prior stroke and hypertension had a 6.1% perioperative stroke rate. The perioperative strokes in patients with prior strokes were not related to the severity of the prior stroke, the interval between the stroke and surgery, the use of a shunt, or the type of anesthesia employed. Patients who have sustained preoperative strokes have a higher incidence of significant medical illnesses and overall cerebrovascular disease. Hypertension and total occlusion of the contralateral carotid artery appear to be particularly poor prognostic indicators of outcome after endarterectomy in these patients. Patients who have sustained preoperative strokes may be more likely to display clinical neurologic symptoms in response to any form of cerebral ischemia. In this higher risk subgroup, intraoperative and surgeon-dependent factors appear to play less of a role

PURPOSE: The optimal anesthetic for use during carotid endarterectomy is controversial. Advocates of regional anesthesia suggest that it may reduce the incidence of perioperative complications in addition to decreasing operative time and hospital costs. To determine whether the anesthetic method correlated with the outcome of the operation, a retrospective review of 3975 carotid operations performed over a 32-year period was performed. METHODS: The records of all patients who underwent carotid endarterectomy at our institution from 1962 to 1994 were retrospectively reviewed. Operations performed with the patient under regional anesthesia were compared with those performed with the patient under general anesthesia with respect to preoperative risk factors and perioperative complications. RESULTS: Regional anesthesia was used in 3382 operations (85.1%). There were no significant differences in the age, gender ratio, or the rates of concomitant medical illness between the two patient populations. The frequency of perioperative stroke in the series was 2.2%; that of myocardial infarction, 1.7%; and that of perioperative death, 1.5%. There were no statistically significant differences in the frequency of perioperative stroke, myocardial infarction, or death on the basis of anesthetic technique. A trend toward higher frequencies of perioperative stroke (3.2% vs 2.0%) and perioperative death (2.0% vs 1.4%) in the general anesthesia group was noted. In examining operative indications, however, there was a significant increase in the percentage of patients receiving general anesthesia who had sustained preoperative strokes when compared with the regional anesthesia patients (36.1% vs 26.4%; p < 0.01). There was also a statistically significant higher frequency of contralateral total occlusion in the general anesthesia group (21.8% vs 15.4%; p = 0.001). The trend toward increased perioperative strokes in the general anesthesia group may be explicable either by the above differences in the patient populations or by actual differences based on anesthetic technique that favor regional anesthesia. CONCLUSIONS: In a retrospective review of a large series of carotid operations, regional anesthesia was shown to be applicable to the vast majority of patients with good clinical outcome. Although the advantages over general anesthesia are perhaps small, the versatility and safety of the technique is sufficient reason for vascular surgeons to include it in their armamentarium of surgical skills. Considering that carotid endarterectomy is a procedure in which complication rates are exceedingly low, a rigidly controlled, prospective randomized trial may be required to accurately assess these differences

BACKGROUND: A history of therapeutic irradiation to the neck complicates the management of carotid artery occlusive disease. Serious surgical concerns are raised regarding alternative incisions, difficult dissections, and adequate wound closure. Pathology may be typical atherosclerotic occlusive disease or radiation-induced arteritis. In order to establish guidelines for the treatment of these patients, we have reviewed our operative experience. PATIENTS AND METHODS: A review of our operative experience over the past 15 years revealed 10 patients with a history of prior irradiation to the neck who underwent 14 carotid operations. RESULTS: The indications for radiation included laryngeal carcinoma and lymphoma. Five patients had undergone previous radical neck dissections, and four patients had permanent tracheostomies. The surgical indications were asymptomatic high-grade stenosis in 7 cases, transient ischemic attack in 4 cases, stroke in 2 cases, and a pseudoaneurysm in 1 case. Conventional carotid endarterectomy with patch angioplasty was used in 10 of the 14 operations. In the remaining four operations, saphenous vein interposition grafting was utilized to replace the diseased segment of carotid artery secondary to a panarteritis. Wound closure required dermal grafting in two of five cases where surgery was performed ipsilateral to a prior radical neck dissection. One perioperative cerebral infarction occurred; there were no other neurologic or non-neurologic complications. All patients are doing well in one- to five-year follow-up, with serial postoperative duplex scans demonstrating no signs of recurrent stenosis. CONCLUSIONS: Patients with a history of irradiation to the neck should be screened for the presence of carotid disease. Carotid occlusive disease should be treated surgically in these patients with the usual indications. Intraoperative surgical management is similar to that of non-irradiated patients. Concerns about difficulty in achieving an adequate endarterectomy plane and about problems with wound closure have generally been unfounded