Results from 88 consecutive prophylactic carotid endarterectomies in cerebral infarction and transitory ischemic attacks

One year of prospective follow-up after carotid thrombendarterectomy--a clinical and duplex study

OBJECTIVES

The aim of this study was to make a prospective evaluation of the carotid arteries after thrombendarterectomy by combined clinical and duplex examination, to define an exact time of development of postoperative restenosis/occlusion and to relate early morphological changes to occurrences of new neurological events.

MATERIAL AND METHODS

Sixty-four patients (66 operations), 48 men and 16 women, mean age of 63+/-8 (SD) years, with transient ischaemic attacks or minor stroke were examined clinically 1 day before and after the carotid surgery. All except 3 patients had stenosis > or =50%. Duplex scanning and periorbital Doppler were performed before aortic arch angiography, within 2 weeks after operation and thereafter at 3, 6 and 12 months.

RESULTS

10 patients experienced minor stroke and one major stroke after operation, in 5 patients connected with occlusion on the operated side, which differed (P<0.01) from 56 patients with open vessels in whom 6 ipsilateral minor strokes occurred. Four of 6 patients with minor stroke, in whom the operated vessels were open, recovered, whereas the neurological deficits were permanent in all 5 patients with occlusion (P<0.05). Duplex scanning confirmed 10 new occlusions and 2 high grade stenoses >75% postoperatively. Persisting morbidity was 11% and no mortality at 3 months' control. At 12 months' control, 1 patient had stroke related to preoperatively diagnosed occlusion on the non-operated side and 14 flow reducing lesions >75% (11 occlusions and 3 stenoses >75%) were found in 57 (24.6%) of examined vessels.

CONCLUSION

occlusion occurs in immediate postoperative period and seems to be a serious complication connected with significantly higher number of persistent neurological events than open vessels.

A systematic review of the risks of stroke and death due to endarterectomy for symptomatic carotid stenosis

BACKGROUND AND PURPOSE

Carotid endarterectomy reduces the risk of carotid territory ischemic stroke ipsilateral to a recently symptomatic severe carotid stenosis. However, the benefit is limited by the risks of stroke and death associated with the operation. Although reported surgical risks vary enormously, there has been no systematic review of the published literature.

METHODS

We performed a systematic review of mortality and the risk of stroke and/or death due to endarterectomy for symptomatic carotid stenosis in studies published since 1980.

RESULTS

Fifty-one studies fulfilled our criteria. Overall mortality was 1.62% (95% confidence interval [CI], 1.3 to 1.9), and the risk of stroke and/or death was 5.64% (95% CI, 4.4 to 6.9). However, there was significant heterogeneity of risk of stroke and/or death (P < .001). The risk varied systematically with the methods and the authorship of the study. The risk of stroke and/or death was highest in studies in which patients were assessed by a neurologist after surgery (7.7%; 95% CI, 5.0 to 10.2) and lowest in studies with a single author affiliated with a department of surgery (2.3%; 95% CI, 1.8 to 2.7). After correcting for study methodology, there was no temporal trend in the risk of stroke and/or death between 1980 and 1995.

CONCLUSIONS

The reported risks of endarterectomy for symptomatic carotid stenosis show significantly greater variability than would be expected by chance. However, much of this variability can be accounted for by differences in methodology and authorship. The 5.6% overall risk of stroke and/or death is consistent with present guidelines.

Risk factors in carotid artery surgery: an evaluation of 414 operations

Four hundred and fourteen carotid reconstructions performed on 352 patients during the years 1971-82 were analysed retrospectively. Fifty-eight percent of the patients were operated on because of hemispheric transient ischaemic attacks (TIA). Twenty-eight percent had suffered a stroke before surgery. The overall combined mortality and morbidity was 7.7%. The procedure mortality was 2.9% with a slightly higher mortality i.e. 5.9% in the stroke group although not significantly higher than among non-stroke patients with a mortality of 1.4%. Patients of more than 70-years had a significantly higher operative mortality (11.1%) than the rest of the patients (1.7%). Non-fatal strokes occurred in 20 patients (4.8%). No correlation was found with the degree of stenosis of the contralateral artery.

Prognosis of high-risk patients with nonoperated symptomatic extracranial carotid tight stenosis

Forty-five patients with symptomatic (20 with transient ischemic attack, 25 with minor stroke) greater than or equal to 75% stenosis of the cervical internal carotid artery had no endarterectomy and received only medical therapy because the surgical risks (severe cardiac disease, chronic obstructive pulmonary disease, hypertension or diabetes with systemic complications, aortic aneurysm) were believed to be unacceptable. During follow-up (mean 48 months), occlusion of the internal carotid artery developed without symptoms in two patients and with symptoms in three patients. The cumulative stroke and/or death rate was 24% at 2 years and 50% at 6 years. The ipsilateral infarct rate was 10% after the first year, but decreased markedly thereafter (2.4% per year), and one third of these infarcts were probably lacunes due to hypertensive small vessel disease. Overall, stroke related to previously symptomatic internal carotid artery stenosis was not the major problem during follow-up but was largely overcome by other strokes and cardiac death.

IMPS (intact months of patient survival): an analysis of the results of carotid endarterectomy

The literature on carotid surgery for lesions appropriate to prior episodes of ischemia has been reviewed. Only one randomized study and six non-controlled reports give useful data (this despite more than thirty years of surgical activity in this field). When analyzed by the IMPS (intact months of patient survival) criterion, the randomized study failed to show benefit from surgery. This failure can be attributed to a high (35%) operative stroke and death rate. That sufficiently low operative stroke and death rates are readily achievable is not clear, however, only two of six relevant non-controlled series reported in the literature had operative stroke and death rates below the 10.4% level calculated as necessary for a "break-even" situation. Three of the six non-controlled series contain sufficient follow-up data to permit IMPS comparison against the "standard" of the control group of the randomized study. Against this "standard" only one of the three non-controlled studies would have "shown benefit" from surgery. Barnett, Plum, and Walton have called for audits of endarterectomy results in institutions in which such surgery is performed. It is suggested that such audits be done by the IMPS method, which gives appropriate weight to the effects of operative, as well as of long-term follow-up, strokes and deaths.

A proposed method for using a reimbursement moratorium to encourage recruitment for a randomized study of carotid endarterectomy

As indicated by Barnett, Plum and Walton, a definitive clinical trial to resolve the issue of the effectiveness of carotid endarterectomy is clearly needed. A proposal to foster such a trial, through a moratorium on third-party reimbursement other than for randomized patients, has herein been presented.

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.

Enteric-coated acetylsalicylic acid plus dipyridamole compared with anticoagulants in the prevention of ischemic events in patients with transient ischemic attacks

From December 1976 through March 1982, 188 patients entered an open non-random study carried out on hospitalized patients with a history of transient ischemic attacks or amaurosis fugax. Ninety-two patients received peroral anticoagulants usually combined with heparin treatment during the first days of treatment, and 96 patients enteric-coated acetylsalicylic acid 0,5 g twice daily plus dipyridamole 75 mg twice daily. The patients were followed up to March 1983, irrespective of whether treatment was changed or not. Recurrent transient ischemic attack or amaurosis fugax occurred more frequently (P less than 0.01) from 2 months of follow-up and throughout the observation period in the antiplatelet-treated group. There were no statistically significant differences between the 2 groups on the originally given treatment for endpoints such as stroke (6 patients on anticoagulants, 12 patients on antiplatelet therapy) or stroke or death (11 patients on anticoagulants, 17 patients on antiplatelet therapy). The findings from this trial suggest that anticoagulant treatment is superior to antiplatelet therapy given in the prevention of ischemic attacks and that this difference mainly exists during the first one to 2 months after onset of transient ischemic attacks or amaurosis fugax.

Evaluation of anticoagulants in patients with cerebral infarction with slight to moderate neurological deficit

In a non-randomized controlled study carried out on 238 hospitalized patients with cerebral infarction, anticoagulant treatment (AC) was compared with the natural course in the prevention of transient ischemic attacks (TIA), cerebral infarction, stroke, stroke or death. 137 patients were allocated to AC, mean follow-up 30.5 months, and 101 patients were allocated to the controls (untreated group), mean follow-up 25.2 months. There were no statistically significant differences among the patients in the group who had suffered TIA (AC treated group 10.2%, untreated group 5.9%), cerebral infarction (AC treated group 10.2%, untreated group 11.9%), stroke (AC treated group 14.6%, untreated group 12.9%), stroke or death (AC treated group 22.6%, untreated group 19.8%). Minor bleedings occurred significantly more frequently (P less than 0.01) in the treated group. Severe bleedings occurred in 8 patients in the treated group (5.8%) compared to 1 of the controls (1%). It is concluded from the trial that AC can only seldom be recommended as prophylactic against new strokes in patients with cerebral infarction due to arterial thromboembolism.

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.