Intra-operative control of carotid thromboendoarterectomy by Doppler spectrum analysis

The authors report their experience with intraoperative Doppler spectrum analysis of carotid flow after thromboendoarterectomy. The method seems to be useful in the early localisation of technical defects potentially responsible for postoperative stroke. In 22 patients operated on consecutively, three major abnormalities were detected, one of the internal and two of the external carotid. This enabled immediate reexploration of the involved artery with restoration of normal flow. This kind of examination is also safe, quick and highly accurate. The authors propose it as a substitute to intraoperative arteriography which is routinely performed by some surgeons after carotid thromboendoarterectomy.

[Intraoperative sonography following endarterectomy of the carotid artery]

The application of intraoperative sonography during carotid endarterectomy will give additional information in vascular diseases, in control of vascular anastomoses in localization of residual arterioma, intima flaps and instrumental damage. Intraoperative sonography is a new device for the vascular surgeon, and should be used to reduce the risk of early restenosis after carotid endarterectomy.

[Stage-III cerebrovascular insufficiency in stenoses and occlusions of the extracranial A. carotis. An indication for surgery?]

Reconstructive surgery was performed on 93 patients with stage III cerebrovascular insufficiency, extracranial stenoses and (or) occlusions of the cerebral blood flow. Compared with the spontaneous course in acute stroke, results of surgery point towards recommending an aggressive procedure provided certain criteria are observed (time limit, absence of haemorrhagia), particularly in view of the potential mortality of the condition. Late prognosis, assessed on the basis of 40 patients subjected to neurological follow-up 4 1/2 years after the operation, can be considered favourable.

[Indications for surgery of carotid artery stenosis with contralateral carotid occlusion]

In a retrospective study the course of 69 patients of the Surgery Department of the University of Heidelberg (66 men, 3 women, mean age 60 years) with carotid artery stenosis with contralateral carotid occlusion has been reported. 10% of the patients with carotid artery stenosis had a contralateral occlusion. Corresponding to the side of occlusion most patients had a preoperative neurological stage IV (55%, 19% stage II, 26% stage I) and corresponding to the side of stenosis most patients had a stage I (57%, 28% stage II, 4% stage III, 12% stage IV). In addition to the stenosis the occlusion had been operated on in 7 patients, in 5 of them the revascularisation was not possible. In 88% the arteriotomy could be closed using a venous patch and in 97% a intraluminal shunt was used. All operations were done under general anesthesia. The early lethality rate was 10%, in one patient a postoperative neurological deficit occurred. The late mortality rate was 21%, in 5% a new neurological deficit could be found (n = 57, mean follow-up: 3.0 years). In relation to the preoperative neurological stage corresponding to the side of stenosis the highest mortality rate was found in patients with stage IV. In a separate analysis of two periods (1962-1978 and 1979-1981) it can be demonstrated that the high early mortality rate is nearly entirely found in the first period with a low operative frequency. In the second period 1979-1981, 33 carotid endarterectomies in patients with contralateral occlusion were operated with a mortality rate of 3%.(ABSTRACT TRUNCATED AT 250 WORDS)

Patency of external and internal carotid artery in the presence of an occluded common carotid artery: noninvasive evaluation with combined cerebrovascular Doppler examination and sequential computertomography

The patency of the external carotid artery (ECA) and internal carotid artery (ICA) in the presence of an occlusion of the common carotid artery (CCA) was evaluated in 7 patients with a symptomatic CCA occlusion by the combined application of cerebrovascular Doppler examination (cv-Doppler) based on continuous-wave equipment and sequential computertomographic scans with intravenous bolus injection of contrast material (sequential CT-scans). Occlusion of the CCA was demonstrated by cv- Doppler and sequential CT-scans and confirmed by routine angiography. A patent ECA was found in all 7 patients by the combined method, but could not be demonstrated by routine angiography in one of these patients. A patent ICA was found in 2 patients by the combined method, while routine angiographic findings concerning the patency of the ICA were equivocal. An occluded ICA was found in 5 patients by the cv-Doppler-sequential CT-scans method, where routine angiographic findings also were equivocal. Operation to restore blood flow in the CCA was performed in 5 patients and successful in 3 patients in whom blood flow from the CCA to the ECA could be achieved in 2 patients, and to the ECA and ICA in one patient, as predicted by the combined cv-Doppler-sequential CT-scans method. Thus, the patency of the ICA in the presence of a CCA occlusion can be reliably evaluated by the combined diagnostic procedure. The method may help to decide for further diagnostic work-up, e.g., specific selective injections and projections in more than two plans during cerebral angiography, and/or successful surgical intervention in a given patient with a CCA occlusion, even if angiographic findings are equivocal.

Current status of carotid endarterectomy for atheromatous disease

The authors discuss the indications for both elective and emergency carotid endarterectomy. Reports on the surgical treatment of asymptomatic bruit and contralateral carotid stenosis are reviewed. The results of endarterectomy for symptomatic carotid disease, including transient ischemic attacks, acute neurological deficit, and complete carotid occlusion, are discussed. The complications and risks of carotid surgery are also presented.

[Must acute carotid thrombosis be surgically treated? 1962-1973: long-term results]

A study of long-term results (mean follow-up: 10.6 years) in 22 patients operated on for acute carotid thrombosis between 1962 and 1973 is reported. In most instances, surgery was performed at the acute phase of a massive cerebrovascular occlusion, usually more than 8 hours after onset (10 cases). Five of these patients (22%) died in the postoperative period. Eight (35%) recovered without residual disease. In six, the condition improved, while it remained unchanged or worsened in three (14%). There were ten delayed deaths, including two from a recurrent cerebrovascular episode and four from cardiac disease. The actuarial survival curve does not differ from that of patients treated conservatively, with rates being 60% at five years, 36% at ten years and 28% at thirteen years. The quality of certain postoperative results suggests that surgical indications at the acute stage of carotid occlusion be reviewed. The study of thirty series from the literature (1 046 cases) shows a 17% mortality rate, while 50% of patients recover or improve. This mortality is significantly lower in recent statistics, under 10%: this improvement may be ascribable to more rigid surgical indications (delay under 6 hours, operation in variable neurologic deficiencies, early diagnosis by the Doppler procedure, better postoperative management). The authors conclude that surgical management of acute carotid thrombosis should no longer be systematically dismissed.

[Intra-operative EEG surveillance during carotid artery desobliteration]

In 35 patients intraoperative EEG-monitoring during carotid desobliteration under general anesthesia was performed. 15 of these patients had preoperatively focal EEG-changes, coinciding frequently with a cerebral infarct or with carotid changes also contralateral to the side of the desobliteration. 18 patients had during the carotid clamping EEG-changes (slowing of frequency and decrease in amplitude) or a worsening of preoperative changes. 15 of these patients had a complete recovery of these changes after unclamping. The EEG changes do occur more frequent in patients who had a cerebral infarct or bilateral carotid changes preoperatively. Since the EEG-changes during the carotid clamping do signal a critical lowering of the brain perfusion, an ischemic etiology has to be assumed. The use of a shunt during the procedure to prevent irreversible ischemic damage seems therefore to be justified.

The critical manipulable variables of hemispheric low flow during carotid surgery

A significant EEG change, 40% power attentuation in anesthetic-induced fast activity, was documented with a tracing record, compressed spectral analysis, and PSA-1 in this series of 195 patients. Interpretation of the change was simplified by the use of the compressed spectral analysis or PSA-1. Quantification of the change was aided by use of the PSA-1, and the graphic output form of this instrument minimized user error. Also, it provided the needed information to those members of the operative team not skilled in EEG interpretation. No immediate postoperative deficits were missed by the monitoring technique. There were no postoperative deficits upon awakening in the 138 patients without processed EEG change. Shunt placement, depth of anesthesia, and intraoperative blood pressure levels were accurately guided throughout the operative procedure by these monitoring techniques. Accurate documentation of an acute significant change permits prompt treatment for restoration of necessary collateral flow. The monitoring technique described continuously provides information for efficacy of treatment. Attention to blood pressure level, which seems to passively determine cerebral collateral flow during clamping, was a very important clinically manipulable variable. Manipulation of this variable with processed EEG control may prove efficacious not only in patients undergoing carotid procedures but in nonsurgical cases of acute carotid occlusion or middle cerebral stem occlusion. Manipulation of identifiable critical variables has a positive impact on the clinical outcome when continuous monitoring is employed. The detection of hemispheric low flow in 34 patients during the preclamp, clamp, and postclamp periods suggests that shunting will not prevent all low flow deficits. Finally, perfection of surgical therapy for stroke prevention necessitates detection and treatment of hemispheric low flow.

Extreme pseudo-occlusion of the internal carotid artery

Angiographic criteria for the identification of patients with angiographic internal carotid artery occlusion but with anatomical patency are presented. The presence of retained contrast material in a caudal atherosclerotic internal carotid artery stump, especially when accompanied by visualization of the internal carotid artery at the base of the skull, suggests that the internal carotid artery may be patent. Two cases of "extreme" pseudo-occlusion are presented, and the indications for extracranial-intracranial bypass and caudal internal carotid artery stump resection are reviewed.

Carotid endarterectomy without angiography

Three patients with unilateral hemispheric symptoms suggestive of extracranial carotid occlusive disease and one patient with bilateral symptoms who were allergic to radiographic contrast media were studied by pulsed Doppler ultrasonic arteriography and real time spectrum analysis. Four high grade (greater than 50% diameter reduction) internal carotid stenoses and one low grade (less than 50% diameter reduction) stenosis were identified. The noninvasive findings were confirmed at endarterectomy in all five arteries. Pulsed Doppler ultrasonic imaging combined with real time spectrum analysis can accurately quantitate the degree of atherosclerotic stenosis at the carotid bifurcation. Experience with these four patients suggests that these techniques can be used in lieu of angiography to evaluate patients who are unable to undergo standard radiographic examination.

[Transluminal dilatation of innominate stenosis in aortic arch syndrome]

Successful percutaneous transluminal dilatation of an anonyma stenosis is reported. The patient was a 40 year-old male with the aortic arch syndrome. Five years before an occlusion of the central carotid artery, as well as anonyma and left subclavian stenoses were treated by means of vascular grafts. On recurrence of the neurological symptoms, reocclusion of the right graft to the anonyma artery and subtotal stenosis of the left carotid bifurcation was noted. The anonyma stenosis was dilated by means of PTD. Haemodynamic success was demonstrated by Doppler sonography.

[Repair of internal carotid artery stenosis. Results of reconstruction in 129 patients]

128 Patients were operated upon consecutively since 1965 for lesions of the carotid bulb (stadium I.: n = 21;stadium II: n = 45;stadium III: n = 33; stadium IV:n - 29), a postoperative neurological deficit was noted in 4,7%, the cerebral lethality was 1,9%. The procedure was done in general anesthesia with moderate elevation of the systemic blood pressure. In case the pressure readings obtained in the stump of the internal carotid artery were below the level of 50 mm of mercury an intraluminal shunt was used. Considered an average lethality of 7% per year 48 patients died during follow-up, 5 for cerebral. 10 for internal medical reasons, in 33 cases the results of post mortem examination was not available. After a mean follow-up time of 7 years 41 patients were re-evaluated 4,8 recurrent stenoses, 2,4% intracranial and 9,4% changes in the contralateral carotid artery were detected. Only 4,8% showed abnormalities on neurological examination, which underscores the importance of non invasive diagnostic tools.