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Cerebral revascularisation in stroke prophylaxis
Insights
Carotid endarterectomy can cause blood pressure instability due to carotid baroreceptor function changes. Risk factors for complications include hypertension and severe carotid artery disease, leading to the
Area of Science:
- Neurosurgery
- Vascular Surgery
- Neurology
Background:
- Cerebral vascular operations, primarily carotid endarterectomies, are performed for stroke prophylaxis.
- Postoperative blood pressure instability is a notable complication of carotid endarterectomy.
Purpose of the Study:
- To investigate the relationship between carotid baroreceptor function and postoperative blood pressure changes after carotid endarterectomy.
- To identify risk factors for complications following carotid endarterectomy.
- To evaluate the outcomes of extracranial-intracranial revascularization procedures.
Main Methods:
- Per-operative carotid sinus nerve recording to assess baroreceptor function.
- Computer analysis of complications in 425 carotid endarterectomies.
- Review of carotid angiograms in 200 patients to assess disease severity.
- Analysis of 79 extracranial-intracranial revascularization procedures.
Main Results:
- Carotid sinus nerve activity correlated with post-endarterectomy changes in carotid sinus mechanical properties.
- Hypertension, contralateral internal carotid artery disease, and lower limb vascular disease were identified as risk factors for carotid endarterectomy complications.
- Severe bilateral internal carotid artery stenosis or occlusion was associated with all severe complications, leading to the concept of the 'reperfusion syndrome'.
- Extracranial-intracranial revascularization showed very low morbidity.
Conclusions:
- Postoperative hypotension after carotid endarterectomy can be managed by local anesthetic near the carotid sinus nerve.
- The severity of internal carotid artery disease is a critical factor in operative complications.
- Extracranial-intracranial revascularization appears to have a low complication rate, but long-term efficacy for stroke and dementia requires further study.
Abstract:
Over 700 cerebral vascular operations have been undertaken on the Surgical Unit of St Bartholomew's Hospital, London, for stroke prophylaxis, the majority being carotid endarterectomies. One of the unique features of the latter procedure is the marked instability of postoperative blood pressure. The relation of this change to interference with carotid baroreceptor function was studied by per-operative carotid sinus nerve recording. It was possible to relate nerve activity to the postend-arterectomy changes in the mechanical properties of the vessel wall in the region of the carotid sinus. Postoperative hypotensive episodes could be reversed by the injection of local anaesthetic alongside the carotid sinus nerve through a cannula left in situ at operation.The complications of 425 carotid endarterectomies were analysed by computer and specific risk factors were found to be hypertension, the presence of contralateral internal carotid artery disease, and the presence of lower limb vascular disease. The carotid angiograms of 200 patients were studied with respect to the extent of the disease at the origin of the internal carotid arteries. The operative complication rate was found to be closely related to the severity of this disease, all severe complications occurring in patients with severe bilateral internal carotid artery stenosis or occlusion. This finding has led to the introduction of the term the ;reperfusion syndrome', and the mechanism of the complication is still under study.Seventy-nine extraintracranial revascularising procedures have been undertaken and this operation has been shown to carry a very low morbidity. The postoperative incidence of recurrent transitory ischaemic attacks (TIAs) and strokes is low, but the longest follow-up period is still only 4 years. The value of the procedure for TIAs and strokes is under study, as is its place in the treatment of patients with dementia.