Faculty Bibliography

The effects of hetastarch and human albumin solutions on perioperative bleeding and coagulation parameters during abdominal aortic aneurysm repair were compared. In two randomized groups of 20 patients, albumin 5% (group 1) or hetastarch 6% (group 2) 1 g/kg was given during surgery. The remaining perioperative fluids consisted of lactated ringers and packed red blood cells. Perioperative coagulation measurements included partial thromboplastin time, prothrombin time, activated clotting time, platelet count, and bleeding time. Estimated blood loss and the total amount of crystalloid and blood infused were also measured. The surgeon, blind to the colloid used, subjectively rated bleeding on a scale of 1 to 10. There was no significant difference between groups for any measured parameter at any time. Measurements of coagulation function were within normal limits for both groups. Hetastarch does not cause clotting disorders in patients undergoing abdominal aortic aneurysm repair, at least if the quantities used in this study are not exceeded.

Vein patch closure after carotid endarterectomy has been used to reduce the incidence of residual and recurrent stenosis at the carotid bifurcation. A rare but potential serious complication is rupture of the vein patch during the early postoperative period. In our experience of 2359 carotid operations performed from 1962 through 1986, saphenous vein was used for closure in 2275 (96.5%) operations. In three patients out of 75 in whom the vein patch had been harvested from the ankle, rupture of the patch occurred 2 to 5 days after uneventful carotid surgery. At emergency reoperation, the central portion of the vein was necrotic, with no evidence of infection. In each case the carotid artery was closed again with fresh thigh saphenous vein, and recovery was uneventful. The use of ankle vein was discontinued in December 1983 in favor of groin saphenous vein, and similar complications have not occurred in more than 600 carotid endarterectomies performed since. Early noninfectious ruptures of the saphenous vein patches have been mentioned in other reported series of carotid operations and have often been related to the use of ankle vein, but they remain unexplained

1. Asymptomatic carotid stenosis up to 80% do not require prophylactic surgery, but should be followed non-infasively. 2. Stenoses of 80-99% are associated with a significant incidence of stroke which is estimated to be 4-10%/year. 3. Occlusion is considered to be an unfavorable end point, since the risk of stroke remains higher than those with patent arteries. 4. The role of carotid endarterectomy is related to the stroke morbidity and mortality of the procedure. To show significant benefits of surgical therapy during the first two years, it is necessary to have a stroke/death rate of less than 3%

Real-time electrocardiographic monitoring for silent myocardial ischemia was performed on 200 patients undergoing peripheral vascular surgery to try to better define those at high risk of perioperative myocardial infarction. The patients were divided into those undergoing abdominal aortic aneurysm or lower extremity revascularization procedures (group I, n = 120) and those undergoing carotid artery endarterectomy (group II, n = 80). Silent ischemia was detected during the preoperative, intraoperative, or post-operative periods in 60.8% of group I and 67.5% of group II patients. Six group I and three group II patients suffered an acute perioperative myocardial infarction with two cardiac deaths. In both groups I and II a variety of parameters based on monitoring of silent myocardial ischemia were compared between the subgroups of patients who had myocardial infarction and those who did not. The results show that in both groups there was a significantly (p less than or equal to 0.05) greater total duration of perioperative ischemic time, total number of perioperative ischemic episodes, and total duration of perioperative ischemic time as a percent of total monitoring time in patients who suffered a perioperative myocardial infarction compared to those who did not. Multivariate logistic regression analysis of preoperative characteristics in all 200 patients showed the occurrence of preoperative silent myocardial ischemia and angina at rest to be the only significant predictors of perioperative myocardial infarction. Thus perioperative monitoring for silent myocardial ischemia might noninvasively identify those patients undergoing peripheral vascular surgery who are at increased risk for perioperative myocardial infarction, permitting implementation of timely preventive measures in selected patients

The incidence and duration of intraoperative silent myocardial ischemia have been shown to be significantly correlated with the incidence of perioperative myocardial infarction in patients undergoing peripheral vascular surgery. To assess the effectiveness of intraoperative beta blockade in limiting such silent myocardial ischemia, a group of 48 patients was treated with oral metoprolol immediately prior to peripheral vascular surgery. The total duration of intraoperative silent myocardial ischemia, the percentage of intraoperative time silent myocardial ischemia was present, the number of intraoperative episodes of silent myocardial ischemia, and the intraoperative heart rate in the treated patients were compared with those in 152 similar but untreated peripheral vascular surgery patients. The patients treated with oral metoprolol had significantly less intraoperative silent ischemia with respect to relative duration and frequency of episodes, a significantly lower intraoperative heart rate, and less intraoperative silent myocardial ischemia in terms of total absolute duration. These results suggest that beta-adrenergic activation may play a major role in the pathogenesis of silent myocardial ischemia during peripheral vascular surgery

Recent reports have suggested that cerebral angiography may not be necessary before carotid endarterectomy is performed in selected patients. To determine if arteriography provides additional information that might influence the decision to operate or the conduct of the operation, a retrospective review was performed of 100 consecutive patients undergoing cerebral angiography and carotid duplex scanning. Eighty of the 100 patients subsequently underwent carotid endarterectomy for neurologic symptoms or asymptomatic stenosis greater than 80%. Among the 20 patients not operated on, three would have undergone unnecessary surgery for mistaken diagnoses had the arteriogram not been obtained. Two other patients in this group of 20 would have had carotid endarterectomy for asymptomatic stenosis in the presence of an equally stenotic tandem lesion. Among the 80 patients operated on, an additional three had the operative procedure altered because arteriographic studies revealed pathologic findings outside the area of duplex scan examination. Thus the use of arteriography altered the management of eight (8%) patients in this group of 100

The evaluation of clinical reports on vascular disease is often made difficult by variations in descriptive terms, clinical classification, and outcome criteria. In 1983 the Joint Council of the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery created the Ad Hoc Committee on Reporting Standards to address these problems and recommend solutions. Some general problems were addressed in the initial report dealing with lower extremity ischemia. This article concerns clinical standards for reports dealing with cerebrovascular disease, suggests a scheme for clinical classification, and recommends standardized reporting practices for grading risk factors, angiographic and other diagnostic findings, and the results and complications of therapeutic intervention

Numerous reports describe the relative effectiveness of external carotid artery (ECA) revascularization in patients with ipsilateral internal carotid artery occlusion. Most, however, suffer from small numbers of patients or lack of detailed follow-up data. In addition, controversy persists regarding the safety with which this procedure can be performed. Twenty-two patients underwent a total of 27 ECA revascularizations. There were no perioperative strokes or deaths. During a mean follow-up period of 46 months, no strokes occurred and only two patients suffered transient ischemic attacks. Revascularization of the ECA is an effective means of treating the patient with ipsilateral internal carotid artery occlusion and may be performed with minimal morbidity and mortality

Among 1500 carotid endarterectomies performed between 1975 and 1984, 11 ipsilateral intracranial hemorrhages (IH) occurred between the first and tenth postoperative days for an incidence of 0.7%. The mortality rate among these patients was 36%. The only recognizable predisposing factor was relief of high-grade carotid stenosis (greater than 90%) whereas other factors such as age (58 to 81 years), preoperative hypertension (systolic blood pressure 120 to 160 mm Hg), preoperative head CT scans showing recent infarction (only one in five positive), and preoperative cerebral infarction (only 1 of 11 patients) did not play a role. All patients had normal coagulation studies. No patient required a shunt because all tolerated cross-clamping of the carotid artery. Postoperative systolic blood pressures were 200 to 240 mm Hg in 6 of 11 patients. The time of occurrence of IH extended from the immediate postoperative period to the tenth postoperative day (mean interval 3.3 days). Treatment consisted of craniotomy in five patients; four survived and one recovered completely. Of the six patients treated nonoperatively, three survived and two completely recovered. IH shares equal incidence with recurrent thrombosis, cross-clamping ischemia, and embolization as a cause of perioperative stroke. Although all except IH can be prevented by current practice, the means of preventing IH are not apparent; however, careful monitoring of blood pressure to prevent uncontrolled hypertension deserves consideration

To assess the intraoperative and postoperative hemodynamic effects of beta-blockade and its benefits in limiting myocardial ischemia and infarction, a group of 32 patients scheduled for abdominal aortic aneurysm (AAA) surgery (group 1) was treated with oral metoprolol immediately before surgery and with intravenous metoprolol during the postoperative period. Mean age was 71 years, and mean ejection fraction was 56% (range 36% to 83%). Eight patients had a preoperative history of angina, 13 had a history of myocardial infarction, and five had electrocardiographic evidence of prior myocardial infarction. A group of 51 closely matched patients with AAA who did not receive metoprolol served as controls (group 2). In group 1, overall hemodynamic tolerance of metoprolol intraoperatively and postoperatively was good, and there was no incidence of congestive heart failure, hypotension, or asthma. Furthermore, in group 1 significant reduction of systolic blood pressure and heart rate was consistently noted at frequent intraoperative intervals and for 48 hr after surgery, with only a transient reduction of cardiac index. In group 1, only one patient (3%) suffered an acute myocardial infarction. In contrast, nine group 2 patients (18%; p less than .05) suffered perioperative myocardial infarction. Furthermore, only four (12.5%) group 1 patients developed significant cardiac arrhythmias as opposed to 29 group 2 patients (56.9%; p less than .001). These data demonstrate that beta-blockade with metoprolol is effective in controlling systolic blood pressure and heart rate both intraoperatively and postoperatively in patients undergoing repair of AAA and can significantly reduce the incidence of perioperative myocardial infarction and arrhythmias