Carotid endarterectomy for cerebrovascular insufficiency: long-term results in 592 patients followed up to thirteen years

Concomitant cerebral and myocardial revascularization

Patients who present with concomitant coronary artery disease and hemodynamically significant carotid artery occlusive disease represent a subset of individuals at high risk for myocardial infarction and stroke. Whether the combined surgical approach favorably influences the outcome of patients requiring major cardiovascular surgical procedures remains controversial. However, it is clear that coronary artery bypass procedure and carotid endarterectomy are each beneficial to patients who have the appropriate indications for each procedure individually. The coincidence of carotid and coronary occlusive disease varies with the type of diagnostic tests involved. Angiographic data suggest a coincidence in the range of 1 to 6 per cent, while vascular laboratory screening data in some studies have indicated a coincidence as high as 12 to 14 per cent--a range that appears to be higher than one might expect from clinical experience. It is clear from analyzing the patient profile of this subset of patients from large clinical reviews that in general they are older and sicker and have a higher incidence of cardiovascular risk factors representing more extensive atherosclerosis. It is also well documented that the neurologic complication rate for all patients undergoing coronary bypass is in the range of 2 per cent. Therefore, it should not be expected that the operative mortality rate and risk of perioperative stroke in patients undergoing the combined reconstructive procedure can equal those for either procedure alone. These patients represent a separate clinical subset at higher risk for perioperative complications and need to be evaluated individually.

Recurrent carotid stenosis. Results and complications of 57 operations

Among 1992 patients undergoing carotid endarterectomy from January 1972 through December 1984, 57 operations were performed in 51 patients for recurrent carotid stenosis. Thirty-four of these cases had undergone initial surgery at this institution while 23 had endarterectomy elsewhere. Fifty-two of the 57 operations were for symptomatic disease while five were for evidence of a progressing lesion. All operative procedures were monitored with intracerebral blood flow measurements and continuous electroencephalograms. Twenty-three patients required intraoperative shunting. There were no complications related to shunt usage or to the period of temporary occlusion in patients who did not require shunting. Recurrent stenosis was related to intimal hyperplasia in 14 cases, recurrent atherosclerosis with interluminal thrombi or degenerated plaque in 27, unexplained soft thrombus in eight, proximal scarring in six, and to aneurysms in two. Intimal hyperplasia was the most common cause for restenosis within 2 years from the date of surgery and developed earlier in patients with a primary closure than in patients closed with a patch graft. The operative complication rate was 10.5% or 4 times the risk of surgery for primary atherosclerosis at this institution. Complications were attributed primarily to intraoperative and postoperative thromboembolic events related to apparent increased thrombogenicity of these vessels. The highest complication rate occurred in the group of patients undergoing surgery for thrombotic material in the internal carotid artery, either primary or with underlying atherosclerosis. There were no neurological complications in the group with myointimal hyperplasia. The authors' experience suggests that on-lay patch grafting without endarterectomy should be used in patients with myointimal hyperplasia. Patients with complicated recurrent atherosclerosis can be treated with endarterectomy and patch grafting, but interposition vein grafts should be considered in cases in which the vessels are extensively damaged by the recurrent plaque or with an unexplained thrombus at the site of previous endarterectomy.

Emergency carotid endarterectomy for patients with acute carotid occlusion and profound neurological deficits

Emergency revascularization procedures for patients with acute stroke are controversial. Thirty-four patients with acute internal carotid artery occlusion documented at the time of emergency endarterectomy were analyzed. Before operation, all these patients had profound neurological deficits including hemiplegia and aphasia. There was a 94% success rate in restoring patency. In follow-up, nine patients (26.5%) had a normal neurological exam, four (11.8%) had a minimal deficit, 10 (29.4%) had a moderate hemiparesis, which was improved over their preoperative deficit, 4 (11.8%) remained hemiplegic, and seven (20.6%) died. The natural history of patients with acute carotid occlusion and profound neurological deficits is dismal. In comparison, 13 patients (38%) made a dramatic recovery. The surgical mortality rate compares favorably with the natural history. Good collateral flow was a good prognostic factor, while a simultaneous middle cerebral artery embolus was associated with a poorer prognosis. An emergency carotid endarterectomy may be indicated in selected patients with acute internal carotid artery occlusion with profound neurological deficits. Full preoperative angiography may identify those patients who would benefit from surgical intervention and reduce the operative mortality rate.

Correlation of postoperative and two-year follow-up angiography with neurological function in 99 carotid endarterectomies in 86 consecutive patients

Eighty-six consecutive patients in 1982 underwent 99 endarterectomies and routine postoperative digital subtraction angiography. Ten vessels were closed primarily and 89 with a patch graft. Minor morbidity was 2%, major morbidity 0%, and mortality 1%, but these varied according to the patient's preoperative medical and neurological function and angiographic findings. Postoperative patency for the common carotid artery (CCA) and internal carotid artery (ICA) was 100% and for the external carotid artery (ECA) 97%. Seventy-nine vessels were evaluated by a DSA 2 years after surgery. There was one asymptomatic occlusion in follow-up and one symptomatic re-stenosis in a patient with a proven heparin induced hypercoagulability state. The three postoperative ECA occlusions were associated with a lethal postoperative stroke, the only ICA occlusion in follow-up, and a 50% stenosis of the CCA in follow-up at the site of ECA occlusion. Vein patch grafting protected the ICA but not the CCA from recurrent stenosis. The carotid slim sign on preoperative angiograms is judged to indicate a patient at high risk of stroke morbidity.

Use of computerized cerebral tomography in selection of patients for elective and urgent carotid endarterectomy

The charts of 181 patients who underwent computerized cerebral tomography (CCT) prior to carotid endarterectomy were reviewed. Findings on cerebral tomography were correlated with clinical presentation, frequency of intraoperative changes in the electroencephalogram (EEG), and occurrence of postoperative neurologic deficits. In the elective group (154 patients), while there was a significant (p less than 0.001) increase of positive ipsilateral CCT findings in stroke patients, 36% of patients with clinical stroke had a negative CCT scan and 21% of patients who were clinically asymptomatic had a positive CCT scan. Results of CCT did not correlate with the incidence of EEG changes (p greater than 0.2) or postoperative stroke rate (3.2%) (p greater than 0.5). Results of urgent carotid endarterectomy were directly related to the findings on preoperative CCT scan. A negative CCT scan was associated with clinical improvement in 88% of patients, one case of neurologic deterioration (5.8%) and no mortality (p less than 0.05). Only 50% of patients operated on acutely with a positive CCT scan showed neurologic improvement while there was a 40% increase in neurologic morbidity and 10% mortality in this group (p less than 0.01). CCT plays a limited role in the preoperative evaluation of patients with clear-cut clinical evidence of thrombo-embolic stroke or transient cerebral ischemia. Findings on CCT scan were of no help prognostically in selecting patients for elective carotid endarterectomy. In contrast, CCT scans have been extremely helpful in planning therapy for patients with acute neurologic problems and evidence of significant extracranial vascular disease.

[Recurrent stenoses following carotid TEA]

Follow-up of 798 patients by Duplex scanning or digital venous angiography 6 months to 13 years after carotid endarterectomy revealed a recurrent stenosis rate of 3.4%. The incidence of the recurrent lesions showed a clear correlation with the operative technique: after closure of the arteriotomy directly (continuous suture) or with a vein patch (303 pat.) the recurrent stenosis rate was 4 times higher than after closure with a dacron patch (495 pat.). Our investigations indicate that recurrent stenosis and occlusions after carotid endarterectomy are largely avoidable. Sufficient length of arteriotomy (5-8 cm), dilatation of the distal internal carotid artery and lumen congruent closure of the arteriotomy with a dacron patch are the pivots of success.

A survey of carotid surgery

One hundred consecutive case notes of patients undergoing internal carotid thrombendarterectomy (TEA) were reviewed in each of seven major teaching hospitals to establish the pattern of practice of carotid surgery. In particular, details of risk factors, indications for surgery, operative details and results of surgery were available for comparison for each hospital compared to the remaining group. An overall mortality rate of 3.3%, which varied between hospitals, from 1% to 6%, was noted. Similar mortality rates were observed when the indication for surgery was transient ischaemic attack (TIA), pre-existing stroke or asymptomatic stenosis.

Review of a community hospital experience with carotid endarterectomy

Carotid endarterectomy was performed 743 times during 56 months in a community hospital by 24 surgeons. The mortality rate was 2.7% and permanent stroke occurred in 1.8%. Temporary postoperative neurologic deficit occurred in 3.5%. The frequency with which the surgeon performed the procedure did not appear significant in the incidence of postoperative morbidity and mortality.

The practice of carotid endarterectomy in a large metropolitan area

All carotid endarterectomies performed in the greater Cincinnati metropolitan area during 1980 were reviewed. For the 431 procedures performed in 16 hospitals, the operative stroke rate was 8.6% (37 of 431), and the operative mortality rate was 2.8% (12 of 431). The combined morbidity and mortality was 9.5% (41 of 431). Fifty percent of the procedures were done for asymptomatic carotid disease (216 of 431) and 50% were done for symptomatic carotid disease (215 of 431). The stroke rate was 5.6% for the asymptomatic patients and 11.6% for the symptomatic patients (difference significant, p less than 0.05). Neurosurgeons and vascular surgeons had similar surgical morbidity. All of the operative strokes involved the hemisphere ipsilateral to the endarterectomy. Fifty-seven percent of the operative strokes (21 of 37) occurred after a neurologically intact interval lasting hours to days. Four occurred following combined endarterectomy-coronary bypass surgery, and one was an intracerebral hemorrhage. The other late strokes (17) occurred without evidence for cardiac embolus or hemorrhage, consistent with a thrombogenic-embologenic operative site, and raising the question of need for adjunctive perioperative medical therapy.

The patient with transient ischemic attacks--is this the time for a new therapeutic approach?

Current and future improvements in treatment to prevent cerebral infarction among patients with transient ischemic attacks may reduce neurological morbidity but may not lead to a proportional improvement in life expectancy. Because the long-term primary cause of death in these patients is myocardial infarction, it is most likely that the most important way to prolong survival may be the vigorous investigation of their cardiac status and the treatment of their coronary artery disease, even if asymptomatic.

Routine electroencephalographic (EEG) monitoring during carotid endarterectomy

Controversy continues concerning the advisability of routine shunting, no shunting, or selective shunting during carotid endarterectomy. Because of its reflection of the physiologic state of the end organ, the authors chose routine 18 lead EEG monitoring as a guide to selective shunting and as an indication of adequate shunt function during all carotid endarterectomies performed from December 1977 through July 1982. In that period, 200 patients underwent 219 endarterectomies under general anesthesia and EEG monitoring. Ischemic EEG changes at the time of carotid cross clamping suggested the need for intraluminal shunts in 16% of patients. Insertion of shunts restored the EEG pattern to normal in all instances, although in two patients, adjustment of the shunt was required to maintain this results. EEG changes requiring shunting occurred in 10% of patients with unilateral disease, in 27% of patients with bilateral disease, and in 42% of patients with unilateral stenosis and contralateral occlusion. Twenty-seven patients had small fixed neurologic deficits before operation. Surgery was not delayed in these individuals who demonstrated no increased requirement for shunts and no new postoperative neurologic deficits. In the group of 150 endarterectomies performed as separate procedures, there was one (0.7%) fixed neurologic deficit after operation, one transient deficit (0.7%), and one death (0.7%). Sixty-nine endarterectomies were performed simultaneously with open heart surgery and were associated with one fixed neurologic deficit (1.4%) and two transient deficits (2.9%). All four deaths in this group were attributable to the cardiac surgical procedures. These results indicate that selective shunting based on EEG monitoring permits the safe performance of carotid endarterectomy, even in patients considered to be at high risk for postoperative neurologic deficit.

Early versus delayed heparin reversal after carotid endarterectomy in the dog. A scanning electron microscopy study

The present study investigates the hematological reaction to arterial injury during the first 10 minutes after endarterectomy in dogs to determine if heparin reversal during this early period predisposes to thrombus formation. Known platelet physiology would predict that heparinization during this early period would be useful to allow a fibrin-free platelet monolayer to form. After systemic heparinization (145 mu/kg) of the experimental animals, 42 endarterectomies were performed. Blood flow was then resumed for specific periods of time, and the vessels were prepared for scanning electron microscopy. Group 1 vessels (from the unheparinized control group) revealed mural thrombus formation after 10 minutes of blood flow. Group 2 vessels revealed the progressive formation of a fibrin-free platelet monolayer after 2, 5, or 10 minutes of blood flow resumption under systemic heparinization. Group 3 arteries, harvested at 10 minutes, underwent immediate (within 1 to 2 minutes after resumption of flow) heparin reversal with protamine sulfate, and demonstrated numerous patches of fibrin covering the platelet monolayer. Group 4 arteries, studied after 3 hours of blood flow, also underwent immediate heparin reversal. Two of these seven specimens had clumps of fibrin overlying the platelet monolayer. The Group 5 vessels had heparin reversal at 10 minutes, and demonstrated no fibrin overlying the platelet monolayer after 3 hours of blood flow. This study demonstrates the formation of a fibrin-free platelet monolayer over the endarterectomized vessel wall within 10 minutes of resumption of flow under systemic heparinization. These findings suggest that heparin may safely be reversed following a carotid endarterectomy if one awaits the initial critical 10 minutes of blood flow.

The influence of ultrasonic Duplex scanning on the management of carotid artery disease

In order to assess the influence of a non-invasive test such as Duplex scanning on the management of patients with suspected carotid artery disease, we reviewed the data on all new referrals (n = 491) during a year. The patients were grouped according to the reason for the referral: 1, patients with focal neurological symptoms lasting less than 24 h (n = 156); 2, patients with focal neurological symptoms lasting longer than 24 h (n = 107); 3, patients with non-focal neurological symptoms (n = 147); 4, patients with asymptomatic bruits (n = 81). For all four groups there was a statistically significant relationship (chi 2; P less than 0 . 005) between the reporting of the presence of a high grade stenosis (more than 50 per cent diameter reduction) and the likelihood that the patient would undergo arteriography. The finding of a high grade stenosis on the arteriogram resulted in a greater number of patients undergoing carotid artery surgery. The results of this study indicate that the report of the non-invasive test influenced the decision-making process in the management of patients with suspected carotid artery disease.

Post-endarterectomy carotid ultrasonic duplex scanning concordance with contrast angiography

The results of ultrasonic duplex scanning combined with spectral analysis are compared with the results of contrast angiography in patients after endarterectomy in which recurrence of carotid arterial disease was suspected. Thirty-six patients underwent a duplex scan study within 3 months of their post-operative angiogram, performed at their physician's discretion (44 studies). The overall accuracy of the method was 80%. Our ability to predict a greater than 50% diameter reduction along with total occlusion was 94%. The measure of agreement corrected for chance between arteriography and duplex scanning as expressed by the Kappa statistic was 0.675 +/- SE (K) 0.096. This level of agreement compared favorably to that of inter- and intra-observer variability in reading cerebral angiograms. The accuracy reported justifies the clinical use of ultrasonic duplex scanning in the detection of recurrent stenosis after carotid endarterectomy.

Carotid artery surgery in patients with minor stroke

Of 229 carotid artery reconstructions, 67 were performed in patients after a minor stroke. In this group of patients the operative mortality was 5.9 per cent, compared with 1.8 per cent in the group of patients without preoperative minor stroke operated upon during the same period of time. The 5-year survival in the stroke group was 86 per cent and in the non-stroke group it was 65 per cent. Excluding the postoperative mortality, the survival increases to 90 and 68 per cent respectively. The difference, which is significant at 6 years (P less than 0.05), is explained by a higher incidence of coronary artery disease in the non-stroke group. The postoperative annual stroke frequency was 2.3 per cent in the stroke group and 2.4 per cent in the non-stroke group. The stroke frequency on the operated side during follow-up was 1.6 per cent per year for both groups together. It seems that a minor stroke is no contraindication to carotid artery reconstruction provided the timing of the operation is correct and other contraindications are considered.

Carotid endarterectomy under regional (conductive) anesthesia

Carotid endarterectomy is reliable in the prevention of strokes due to arteriosclerotic disease at the carotid bifurcation. This is a retrospective review of 314 carotid endarterectomies performed at the University Health Center of Pittsburgh. The objectives of the study were to determine if regional anesthesia was a safe technique for carotid endarterectomy and to determine whether the neurologic complications that occurred were embolic or ischemic in origin. In patients who were neurologically intact before operation, the perioperative mortality was 0.88% and the incidence of neurologic complications was 3.1%. This is comparable to the current literature. Observations of the awake patient suggested that half the neurologic deficits that occurred in this series were due to embolization rather than to cerebral ischemia. Further more, the incidence of non-neurologic complications under general anesthesia was 12.9%. Under regional anesthesia, the incidence of non-neurologic complications was 2.8%. The data supports carotid endarterectomy under regional block as safe and reliable method.

Concomitant carotid and coronary artery reconstruction

Data are presented on 68 patients who underwent concomitant carotid endarterectomy (CE) and coronary artery bypass surgery (CAB) at Emory University Hospital from January 1974 to February 1981. This group is then compared with a randomly selected, matched population without known carotid disease who underwent CAB alone. Asymptomatic bruit was the reason for investigation in 40 patients (59%); another 23 patients (34%) experienced transient cerebral ischemic attacks (TIAs); and five patients (7%) had TIA and prior stroke. Carotid stenoses (>75% luminal narrowing) were demonstrated as follows: isolated left, 24 patients; isolated right, 27 patients; and bilateral lesions, 16 patients. One patient had innominate artery stenosis. Associated total occlusion of one or both vertebral arteries was demonstrated in six patients. Ninety-seven per cent of patients had disabling angina pectoris prior to operation; the angina was unstable in 57%, 15% had congestive heart failure, and 54% had had at least one prior myocardial infarction (MI). Single-vessel coronary disease was present in 12.5% of patients, double in 37.5%, triple in 41.1%, and left main stenosis in 9%; 43% of patients had abnormal ventricular contractility. CE was performed on 67 patients (36 left and 31 right); aortocarotid bypass was performed on one. The CE procedures were performed immediately prior to the sternotomy for CAB under the same anesthesia. CAB consisted of single bypass in eight patients (11.8%); double in 16 patients (23.5%); triple in 22 patients (32.4%); and quadruple or more in 22 patients (32.4%) (mean = 2.9 grafts per patient). There was no hospital mortality. Perioperative MI occurred in 2.0% and stroke with residual deficit in 1.3%. Cumulative survival is 98.5% at two years. Sixty-three patients (92%) reported improvement or elimination of anginal symptoms after operation. Rehospitalization for stroke was necessary in 3.7% patients. Postoperative activity levels are; self-care only, 3.9%; normal daily activity only, 17.6%; moderate exercise capability, 45%; and vigorous exercise capability, 33%. Comparison was made with a group of 84 randomly selected patients who underwent CAB alone during the same time interval. Data revealed no significant difference between the groups regarding sex, angina subset, ventricular function, coronary anatomy, vessels grafted, perioperative stroke or MI, mortality, or postoperative activity capability. Older age (59.8 vs. 55.6, p < 0.01) and less complete coronary revascularization possible (66 vs. 84%, p < 0.05) in the CECAB group were the only significant differences. Carotid stenosis co-existing in patients requiring CAB should be concomitantly corrected with the same risk and results expected from CAB alone.

The current status of carotid artery surgery

The natural history of extracranial cerebrovascular disease and available alternatives in its treatment are reviewed. An evaluation of the evidence suggests that carotid endarterectomy is the treatment of choice in patients with transient ischemic deficits, provided that an anatomically appropriate lesion can be identified. These patients have a 25-38% chance of stroke if untreated, which can be reduced to 5-10% by carotid endarterectomy. Patients with asymptomatic carotid stenosis who are good operative risks are also candidates for surgery, although this issue remains controversial. Patients with small asymptomatic ulcerated carotid plaques have a relatively benign prognosis and should not undergo preventive carotid surgery. Carotid surgery is occasionally indicated in patients with vertebral basilar insufficiency and carotid stenoses, fibromuscular dysplasia, or carotid kinks associated with symptoms of ischemia. Carotid endarterectomy may be performed with an overall mortality of 1-2% and morbidity of 2-5% if the patients are carefully selected and the surgical team is expert.

Noncardiac operations after coronary revascularization

In 35 patients who had had earlier myocardial revascularization, a total of 44 noncardiac operations under general or spinal anesthesia were carried out. There was one cardiac death and three postoperative complications. Compared with the risk of general anesthesia and noncardiac surgical procedures in patients with coronary artery disease who have not had coronary revascularization, this is a major improvement. We conclude that myocardial revascularization provides significant protection against the risk of cardiac complications and death for patients with ischemic heart disease in whom general anesthesia and noncardiac procedures are needed.

The effect of heparin reversal after carotid endarterectomy in the dog. A scanning electron microscopy study

The purpose of this study was to determine reversal of heparin, immediately after carotid endarterectomy would have an adverse effect on the thrombogenicity of the endarterectomized vessel wall. After systemic heparinization, unilateral common carotid endarterectomies were performed under the operating microscope on 14 dogs. Half of the animals were given protamine sulfate to reverse the heparin. Three hours after resumption of blood flow, these arteries, as well as contralateral vessels used as controls for fixation technique, were perfused with glutaraldehyde and prepared for scanning electron microscopy (SEM). Thrombin clotting times were measured throughout the experiments. Sections of the endarterectomized portions viewed by SEM showed nearly total coverage of the exposed collagen of the media with flattened platelets. There were scattered leukocytes, but few erythrocytes, little fibrin, and no true thrombus. There were no difference between the animals that received heparin reversal and those that did not. A group of five additional arteries underwent the same procedure except that no heparin was given. As expected, large amount of thrombus had formed within the lumina of these control vessels by 3 hours. Since previous studies suggest that arterial thrombosis usually occurs within 3 hours of endothelial injury, the authors conclude that total reversal of heparin does not increase thrombogenicity of the endarterectomized vessel. This suggests that heparin may be safely reversed in patients to help maintain postoperative hemostasis.

Fatal myocardial infarction following carotid endarterectomy: three hundred thirty-five patients followed 6-11 years after operation

Routine coronary angiography has been recommended to all patients undergoing carotid endarterectomy at the Cleveland Clinic since 1978. Patients found to have severe, correctable coronary artery disease (CAD) have been advised to undergo myocardial revascularization as a staged or combined procedure in conjunction with carotid endarterectomy in an attempt to reduce the incidence of fatal myocardial infarction during the postoperative period, and during the late follow-up interval. In order to provide an historic standard with which the results of this approach may eventually be compared, complete follow-up information has been obtained for 95% of 335 consecutive patients who underwent carotid endarterectomy between 1969 and 1973. Fatal myocardial infarction accounted for 60% of early deaths within 30 days of operation and occurred in 1.8% of the entire series. Among the patients who survived operation, the five-year mortality rate was 27%, and the 11-year mortality rate was 48%. Myocardial infarction caused 37% of the deaths that occurred within five years after operation and 38% of the deaths that have occurred within 11 years. Differences in the incidence of fatal myocardial infarction within five years after operation between a group of 116 patients who had no clinical evidence of CAD and a group of 209 patients suspected to have CAD attained statistical significance (p less than 0.1) despite the fact that 67 patients suspected to have CAD eventually underwent myocardial revascularization. Improvement in actuarial survival (p less than 0.05) and reduction in the late mortality rate (p less than 0.01) were statistically significant for the subset of patients with suspected CAD who had aortocoronary bypass graft procedures.

Use of combined oculoplethysmography, carotid phonoangiography and Doppler in the non-invasive diagnosis of extracranial carotid occlusive disease

One hundred and eight patients were studied with fluid-filled oculoplethysmography and carotid phonoangiography (OPG-CPA) and by arteriography. Thirty-two patients also had "Doppler evaluation" of supraorbital arterial flow. The OPG-CPA correctly predicted the degree of occlusion in 76% of the involved vessels, including the degree of occlusion of each carotid for each patient (63%). The OPG-CPA identified at least one obstructing carotid lesion in 51 of the 56 (91%) patients with obstructing lesions demonstrated by arteriography. On a per patient basis, which requires that both carotids be correctly assessed, the OPG-CPA had a false negative rate of 9.6% and false positive rate of 50%. The supraorbital artery "Doppler evaluation" had an accuracy rate of 66%, a per patient false negative rate of 50%, and a per patient false positive rate of 12%. The OPG-CPA and supraorbital artery "Doppler evaluation" are adjunctive tests for evaluating patients with cerebral vascular insufficiency and should not, at present, replace arteriography in symptomatic patients or in certain asymptomatic patients.

Carotid thromboendarterectomy: a reappraisal. Criteria for patient selection

Thromboendarterectomy performed in 35 patients with symptoms distal and ipsilateral to an occluded internal carotid artery resulted in patency in 19 cases (53%). Two factors that influence successful operation are early intervention following occlusion and good collateral circulation. In only 12 patients (34%) could the interval from occlusion to surgery be confidently determined. Four of these vessels, occluded for up to 7 days (100%), and five of eight vessels (63%), occluded for up to 4 weeks, were reopended. In the remaining patients, where the duration of occlusion was indefinite, greater reliance was placed on the evaluation and grading of angiographic collateral supply distal to the occlusion. Patients with Grade 1 to 3 collateral supply should not be explored unless occlusion occurred very recently. Patients with Grades 4 and 5 collateral supply are considered for carotid exploration regardless of the duration of the occlusion, as an alternative to other methods of revascularization.

Postoperative stroke in cardiac and peripheral vascular disease

The postoperative stroke rate in 330 patients requiring coronary artery (170) or peripheral vascular (160) surgery was compared with the presence of carotid bruits and the results of noninvasive screening (Doppler imaging and spectral analysis of flow) to determine prevalence and significance of carotid lesions) and their relationship to perioperative stroke. Carotid lesions were suspected because of bruits in 70 patients with peripheral vascular disease (PVD) and in 28 patients with coronary artery disease (CAD). Noninvasive tests showed high grade stenosis or occlusion in 62 patients with PVD and in 14 with CAD. Forty-four patients with PVD and 101 patients with CAD had normal Doppler studies. The rest in both groups had plaquing without major stenosis. Noninvasive tests uncovered severe, occult lesions in only 13 patients (9 PVD, 4 CAD). Postoperative neurologic complications occurred in 16 patients (13 strokes: 5 PVD, 8 CAD and 3 TIAs: 2 PVD, 1 CAD). Thirteen neurologic complications occurred in patients having nonstenotic plaques or normal carotids without bruits. Only three of the strokes and 1 TIA occurred in patients with bruits and detectable carotid stenosis. Few of the postoperative strokes or TIAs were focal (2 PVD, 1 CAD), and the rest were nonfocal. None of the postoperative strokes or TIAs were associated with postoperative carotid occlusion. Physical examination is not an accurate method of determining severity of carotid disease. Severe carotid stenosis is more common in PVD patients than in CAD patients, but there is no significant difference in postoperative stroke rate. No direct relationship has been found between a bruit, severity of disease, and incidence of perioperative stroke.

[Late results of reconstructive surgery for supraaortic occlusions (author's transl)]

Internal carotid endarterectomy is an effective and longlasting means of preventing cerebrovascular accidents. After 1-16 years it was entirely successful in 97.8% of asymptomatic patients; 79.3% of patients with transient ischemic attacks experienced no further symptoms, 13% were improved. In patients with acute strokes 20% were cured, 70% improved, and 10% unchanged. The follow-up of patients with completed stroke yielded no further neurological deficit. The late results 1-14 years ater reconstruction of the other supraaortic vessels were good in 92,5% of cases.

David M. Hume Memorial Lecture. An overview of the stroke problem in the carotid territory

In a review of 1,000 carotid endarterectomies performed over a 20 year period, there was relief of transient ischemic attacks in approximately 85% of patients, an operative mortality of 1.3%, due almost exclusively to myocardial infarction, and a recurrent stenosis rate of 3.1%. Coexisting cardiac disease constitutes the greatest operative hazard. Continuous electroencephalographic monitoring is a reliable method of detecting inadequate cerebral perfusion during carotid cross clamping and for the selective use of a temporary inlying carotid shunt. An atherosclerotic plaque in the carotid system constitutes a greater risk than elsewhere in the peripheral arterial system and should not be considered an innocent lesion. Prophylactic carotid endarterectomy can be performed with almost no mortality and morbidity. Antiplatelet agents, while useful in reducing the incidence of transient ischemic attacks, do not seem to provide equal protection against stroke and death from stroke.