Since the 1950s carotid endarterectomy has been performed in patients with symptomatic carotid artery stenosis, based on suggestive but inconclusive evidence for its effectiveness. Only during the last 5 years have randomized studies clarified the indications for surgery. In preparing this report, panel members used the same rules of evidence used in the previous report1 2 (Table⇓).

View this table:

 Table 1. 
Levels of Evidence and Grading of Recommendations



Few studies have analyzed control of risk factors in a randomized, prospective manner following carotid endarterectomy. However, a wealth of data are available regarding the general relationship between risk factor control and stroke risk. These data provide some guidance for the care of endarterectomy patients.

### Hypertension

Hypertension is the most powerful, prevalent, and treatable risk factor for stroke.3 Both systolic and diastolic blood pressure are independently related to stroke incidence. Isolated systolic hypertension, which is common in the elderly, also considerably increases risk of stroke. Reduction of elevated blood pressure significantly lowers risk of stroke. Meta-analyses of randomized trials found that an average reduction in diastolic blood pressure of 6 mm Hg produces a 42% reduction in stroke incidence.3 4 Treatment of isolated systolic hypertension in people older than 60 years also reduces stroke incidence by 36% without an excessive number of side effects such as depression or dementia.5 Long-term care of patients after endarterectomy should include careful control of hypertension (Grade A recommendation for treatment of hypertension in general; Grade C recommendation for postendarterectomy care).

Perioperative treatment of hypertension after carotid endarterectomy represents a special situation. Poor control of blood pressure after endarterectomy increases risk of cerebral hyperperfusion syndrome.6 7 8 9 This complication is characterized by unilateral headache, seizures, and occasionally altered mental status or focal neurological signs. Neuroimaging may show intracerebral hemorrhages10 11 12 or white …

Guidelines for carotid endarterectomy: a statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association

Objective: To review the use of transcranial Doppler ultrasonography (TCD) and transcranial color-coded sonography (TCCS) for diagnosis. Methods: The authors searched the literature for evidence of 1) if TCD provides useful information in specific clinical settings; 2) if using this information improves clinical decision making, as reflected by improved patient outcomes; and 3) if TCD is preferable to other diagnostic tests in these clinical situations. Results: TCD is of established value in the screening of children aged 2 to 16 years with sickle cell disease for stroke risk (Type A, Class I) and the detection and monitoring of angiographic vasospasm after spontaneous subarachnoid hemorrhage (Type A, Class I to II). TCD and TCCS provide important information and may have value for detection of intracranial steno-occlusive disease (Type B, Class II to III), vasomotor reactivity testing (Type B, Class II to III), detection of cerebral circulatory arrest/brain death (Type A, Class II), monitoring carotid endarterectomy (Type B, Class II to III), monitoring cerebral thrombolysis (Type B, Class II to III), and monitoring coronary artery bypass graft operations (Type B to C, Class II to III). Contrast-enhanced TCD/TCCS can also provide useful information in right-to-left cardiac/extracardiac shunts (Type A, Class II), intracranial occlusive disease (Type B, Class II to IV), and hemorrhagic cerebrovascular disease (Type B, Class II to IV), although other techniques may be preferable in these settings.

https://n.neurology.org/content/neurology/62/9/1468.full.pdf

Assessment: Transcranial Doppler ultrasonography: Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

Background and Purpose Indications for carotid endarterectomy have engendered considerable debate among experts and have resulted in publication of retrospective reviews, natural history studies, audits of community practice, position papers, expert opinion statements, and finally prospective randomized trials. The American Heart Association assembled a group of experts in a multidisciplinary consensus conference to develop this statement. Methods A conference was held July 16-18, 1993, in Park City, Utah, that included recognized experts in neurology, neurosurgery, vascular surgery, and healthcare planning. A program of critical topics was developed, and each expert presented a talk and provided the chairman with a summary statement. From these summary statements a document was developed and edited onsite to achieve consensus before final revision. Results The first section of this document reviews the natural history, methods of patient evaluation, options for medical management, results of surgical man...

Guidelines for Carotid Endarterectomy A Multidisciplinary Consensus Statement From the Ad Hoc Committee, American Heart Association

Microemboli detected by transcranial Doppler monitoring in patients during carotid angioplasty versus carotid endarterectomy.

Guidelines for carotid endarterectomy: a statement for healthcare professionals from a Special Writing Group of the Stroke Council, American Heart Association.

A study was performed to investigate the clinical significance of microembolization detected by transcranial Doppler ultrasonography (TCD) by determining the quantity and character of emboli and correlating these with neurological and psychometric outcome, fundoscopy, automated visual field testing and computed tomographic brain scans in 100 consecutive patients undergoing carotid endarterectomy. Embolization was detected in 92 per cent of successfully monitored operations. Most emboli were characteristic of air and not associated with adverse clinical outcome. However, more than ten particulate emboli during initial carotid dissection correlated with a significant deterioration in postoperative cognitive function. A relationship between persistent particulate embolization in the immediate postoperative period, and both incipient carotid artery thrombosis and the development of major neurological deficits was observed. Immediate intervention, based on TCD evidence of embolization, has the potential to avert neurological deficits resulting from particulate embolization.

Clinical relevance of intraoperative embolization detected by transcranial Doppler ultrasonography during carotid endarterectomy: A prospective study of 100 patients

A comparison of quality control methods applied to carotid endarterectomy

We were interested to read the prospective study by Levi et al. (1991) describing the transcranial Doppler (TCD) detection of emboli in the early postoperative phase of carotid endarterectomy. Their finding that embolization was significantly associated with the development of postoperative strokes strongly supports the findings in our own prospective study of perioperative embolization which the authors kindly referred to in their article (Gaunt et al., 1994). The results from their well-conducted study provide further confirmation of the importance of the early postoperative phase in the occurrence of perioperative strokes. However, it should not be ignored that TCD can detect and help prevent strokes occurring during all the phases of the operation, especially embolization of unstable plaque during the initial dissection of the carotid artery and haemodynamic stroke resulting from either inadequate cerebral blood supply at the time of clamping or shunt malfunction (Gaunt e al., 1994). There are two essential features of an effective monitoring method: (i) it can detect the majority of abnormalities; and (ii) abnormalities are detected soon enough to enable corrective action to prevent permanent neurological damage (Gauntet al., 1997). TCD detects embolization in the postoperative phase before the development of neurological deficits, and in our original study we advocated immediate reoperation to remove the thrombus from the carotid artery and prevent further embolization (Gaunt et al., 1994). However, the possibility that this may represent an overtreatment in some cases, and occasional practical difficulties in returning a patient to theatre, prompted us to investigate the alternative therapy of dextran 40 infusion. Our centre recently completed a prospective study of 100 consecutive patients undergoing carotid endarterectomy investigating the use of dextran 40 to arrest postoperative embolization detected by TCD monitoring. Overall, 48% of patients experienced emboli in the 6-h postoperative monitoring period; however, only 8% had .50 and 5%.100 emboli. An incremental dextran infusion was instituted in all patients with.25 emboli detected in any 10-min period of monitoring and this resulted in cessation of embolization in

/pdf/transcranial-doppler-detected-cerebral-microembolism-1pnm6c4amj.pdf

J.L. Smith

Papers

Clinical relevance of intraoperative embolization detected by transcranial Doppler ultrasonography during carotid endarterectomy: A prospective study of 100 patients

A comparison of quality control methods applied to carotid endarterectomy

Transcranial Doppler detected cerebral microembolism following carotid endarterectomy.

A Policy of Quality Control Assessment Helps to Reduce the Risk of Intraoperative Stroke During Carotid Endarterectomy

Transcranial Doppler directed dextran therapy in the prevention of carotid thrombosis: three hour monitoring is as effective as six hours.