Seizures following carotid endarterectomy

Perioperative Stroke

PURPOSE OF REVIEW

This review overviews perioperative stroke as it pertains to specific surgical procedures.

RECENT FINDINGS

As awareness of perioperative stroke increases, so does the opportunity to potentially improve outcomes for these patients by early stroke recognition and intervention. Perioperative stroke is defined to be any stroke that occurs within 30 days of the initial surgical procedure. The incidence of perioperative stroke varies and is dependent on the specific type of surgery performed. This chapter overviews the risks, mechanisms, and acute evaluation and management of perioperative stroke in four surgical populations: cardiac surgery, carotid endarterectomy, neurosurgery, and non-cardiac/non-carotid/non-neurological surgeries.

Rare Complication of Carotid Stenting: New-Onset Refractory Status Epilepticus: A Study of Five Patients

Introduction:

New-onset refractory status epilepticus (NORSE) is uncommon and almost 50% of cases are cryptogenic. We report the rare development of NORSE following carotid artery stenting (CAS), a procedure which is increasingly being used to treat the carotid stenosis.

Materials and Methods:

Patients who developed NORSE following CAS for the prevention of stroke over a period of 5 years were analyzed retrospectively. The degree of internal carotid artery stenosis (ICA) was estimated as per the NASCET criteria.

Results:

We analyzed five patients (age: 56–83 years). NORSE was reported within 30 min to 14 days post-CAS. Status epilepticus was focal in two patients, generalized in two, and one had nonconvulsive status epilepticus. All patients were treated with multiple antiepileptic drugs. Four patients recovered and survived and one succumbed. Two patients had comorbid hypertension and two had diabetes and hypertension. Four patients had hemiparesis due to the contralateral middle cerebral artery territory infarction and one patient had syncope. Two patients had postinfarction gliosis.

Conclusions:

We report a new cause of NORSE, following CAS. Stroke resulting in gliosis and cerebral hyperperfusion syndrome are the proposed mechanisms.

Neurologic complications of cardiac and vascular surgery

This chapter will provide an overview of the major neurologic complications of common cardiac and vascular surgeries, such as coronary artery bypass grafting and carotid endarterectomy. Neurologic complications after cardiac and vascular surgeries can cause significant morbidity and mortality, which can negate the beneficial effects of the intervention. Some of the complications to be discussed include ischemic and hemorrhagic stroke, seizures, delirium, cognitive dysfunction, cerebral hyperperfusion syndrome, cranial nerve injuries, and peripheral neuropathies. The severity of these complications can range from mild to lethal. The etiology of complications can include a variety of mechanisms, which can differ based on the type of cardiac or vascular surgery that is performed. Our knowledge about neuropathology, prevention, and management of surgical complications is growing and will be discussed in this chapter. It is imperative for clinicians to be familiar with these complications in order to narrow the differential diagnosis, start early management, anticipate the natural history, and improve outcomes.

Hyperperfusion Syndrome After Stenting for Intracranial Artery Stenosis

Hyperperfusion syndrome (HPS) is a rare but potentially devastating postoperative complication developing after endarterectomy and carotid stenting. Limited information is available about this complication. The aim of this study was to assess the incidence of HPS and risk factors leading to its development. We retrospectively reviewed 178 consecutive cases of patients who underwent stenting of intracranial artery revascularization. We analyzed the association between HPS and patient's age, collateral vascular supply of the lesion, the interval between operation and the last occurrence of ischemic symptom, adequacy of blood pressure control after the operation, and other risk factors such as diabetes, smoking, hypertension, and gender. Of 178 included patients, we found HPS in six cases (3.4%). Failure to strictly control postoperative blood pressure, a less than 3-week long interval between operation and the last occurrence of ischemic symptom, and poor collateral circulation were significantly associated with the development of HPS. The aforementioned factors are predictors for HPS. We argue that nitroprusside should not be used to control blood pressure after the operation because its use permits considerable blood pressure fluctuations.

Cerebral Hyperperfusion Syndrome

Cerebral reperfusion following carotid endarterectomy occasionally causes cerebral hyperperfusion syndrome. This is a rare but important complication and this case report acted as a stimulus for a literature review of this problem.

A 60-year-old businessman had a right carotid endarterectomy for a severe stenosis which had caused recurrent attacks of amaurosis fugax. The left internal carotid artery had occluded asymptomatically. The operation and his immediate postoperative recovery were entirely uneventful but he developed right-sided headaches and focal sensory motor seizures. He subsequently recovered.

Hemodynamically compromised patients appear to be at greater risk and as the mortality of the operation is reduced and more complex patients are treated, it is likely that this unusual complication will increase in incidence.

Seizures and the neurosurgical intensive care unit

The cause of seizures in the neurosurgical intensive care unit (NICU) can be categorized as emanating from either a primary brain pathology or from physiologic derangements of critical care illness. Patients are typically treated with parenteral antiepileptic drugs. For early onset ICU seizures that are easily controlled, data support limited treatment. Late seizures have a more ominous risk for subsequent epilepsy and should be treated for extended periods of time or indefinitely. This review ends by examining the treatment algorithms for simple seizures and status epilepticus and the role newer antiepileptic use can play in the NICU.

Stepwise revascularization by carotid endarterectomy after balloon angioplasty for symptomatic severe carotid artery stenosis

The authors report a novel stepwise carotid revascularization method to prevent perioperative complication. A 68-year-old man presented with left hemiparesis and dysarthria caused by severe stenosis of the right cervical internal carotid artery. According to the preoperative cerebral blood flow evaluation and plaque characterization, the patient was at risk for postoperative hyperperfusion and ischemic complications after carotid artery stenting. Initially, the patient underwent percutaneous angioplasty using an undersized balloon. Fifteen days later, the patient underwent a carotid endarterectomy. The surgical specimen obtained during the carotid endarterectomy showed the presence of typical vulnerable plaque. Of note was the complete preservation of the thin fibrous cap. The postoperative single-photon emission tomography images showed no signs of hyperperfusion, and the patient developed no neurological symptoms after each of the procedures.

[Delayed post-operative epileptic seizure after carotid endarterectomy: a case of cerebral hyperperfusion syndrome?]

The so-called cerebral hyperperfusion syndrome is basically due to a lack of cerebral autoregulation, inability to control the restoring of flow after revascularisation surgery. It present clinically as intense migraine, epileptic seizures, or neurological focality. It may even progress to an intracerebral haemorrhage. It usually appears a few days after surgery. We present the case of a patient subjected to a carotid endarterectomy, who had an epileptic episode in the late post-operative period. We attributed a cerebral hyperperfusion syndrome as the most likely cause. Knowledge of this syndrome may help to correctly orientate and treat the neurological complications that appear after this type of surgery.

Treatment of seizures in the neurologic intensive care unit

Seizures occur more often in the neurologic intensive care unit (NICU) than in general or other specialty ICUs, in part because of the patient population, but also due to the enhanced neurologic monitoring undertaken in such units. Especially important for the detection of seizures is the use of specialty trained personnel and the use of continuous electroencephalographic monitoring. The etiology of seizures often can be categorized either by primary brain pathology, at macro- or microscopic level, or by physiologic derangements of critical care illness, such as toxic or metabolic abnormalities. Particular etiologies at risk for seizures include hemorrhagic stroke and traumatic brain injury. The use of prophylactic antiepileptic drug administration remains controversial. If seizures occur, patients are typically treated with parenteral antiepileptic drugs. The duration of treatment is unclear in most situations, but data support limited treatment for early-onset ICU seizures that are easily controlled, with treatment not extending beyond a few weeks or a month. Late seizures, which occur more than 2 weeks after the insult, have a more ominous correlative risk for subsequent epilepsy and should be treated for extended periods of time or indefinitely. Electrolyte and glucose abnormalities, when corrected, usually lead to seizure control. This review concludes by examining the treatment algorithms for simple seizures and status epilepticus and the role newer antiepileptic use can play in the NICU.

Staged angioplasty for carotid artery stenosis to prevent postoperative hyperperfusion

OBJECTIVE

Hyperperfusion (HP) is a rare but potentially devastating complication after carotid revascularization. This report describes the clinical efficacy of staged angioplasty (SAP) for carotid artery stenosis to prevent HP after carotid revascularization.

METHODS

Eighteen of 143 patients with high-grade internal carotid artery stenosis scheduled for angioplasty were considered at high risk of postprocedure HP based on their severely impaired cerebral blood flow (CBF) and cerebral vasoreactivity, which were determined using single-photon emission computed tomography with acetazolamide. Nine of the high-risk patients were treated with carotid artery stenting and the other 9 were treated with SAP, which consisted of balloon angioplasty with undersized balloon catheters (Stage 1) followed by carotid artery stenting 1 to 2 months later (Stage 2).

RESULTS

In the regular carotid artery stenting group, 5 of 9 patients (56%) showed HP phenomenon on single-photon emission computed tomography just after stenting, and 1 patient (11%) developed status epilepticus owing to HP. In the SAP group, none of the 8 patients treated by SAP or the 1 patient who required stent placement during the first stage owing to a wall dissection developed postprocedure HP phenomenon or HP syndrome.

CONCLUSION

SAP decreased the HP phenomenon on single-photon emission computed tomography after performing these procedures in selected patients. Although additional intervention is needed, SAP is considered a relatively simple and effective method to avoid HP in patients at high risk of HP after carotid revascularization.

Seizures and status epilepticus in the critically ill

Seizures represent stereotypic electroencephalographic (EEG) and behavioral paroxysms as a consequence of electrical neurologic derangement. Seizures are usually described as focal or generalized motor convulsions; however, nonconvulsive seizures that occur in the absence of motor activity may escape clinical detection. Because of the admission diagnoses and dramatic physiologic and metabolic derangements common to critically ill patients, the entire spectrum of seizure disorders may be encountered in the ICU. Seizures in the ICU are attributable to primary neurologic pathology or secondary to critical illness and clinical management. For optimal treatment, early diagnosis of the seizure type and its cause is important to ensure appropriate therapy. Convulsive status epilepticus requires emergent treatment before irreversible brain injury and severe metabolic disturbances occur.

Hyperperfusion Syndrome after Carotid Endarterectomy

The hyperperfusion syndrome is a rare delayed postoperative complication of carotid endarterectomy (CEA) characterized by headache and seizure, with or without intracranial edema or hemorrhage. Between January 1996 and December 2003, 1,602 CEAs were performed. Six patients (0.4%) developed symptoms of hyperperfusion within 2 weeks of surgery. All patients had critical stenoses, five > or =90% and one 80-90%, with poor backbleeding from the distal internal carotid artery noted at operation in all cases. Five patients were asymptomatic prior to operation; one had a hemispheric transient ischemic attack. Three patients had severe contralateral internal carotid disease (two occlusions and one severe stenosis). Two patients developed severe, self-limiting headache that prolonged hospitalization. Three patients had ipsilateral intracranial bleeding, two occurring after an uneventful postoperative course. After initial discharge from the hospital, severe intracranial hemorrhage caused death in two patients. One patient experienced focal seizures 1 week after discharge. Hypertension did not appear to be related to the symptoms in any case. During the study period, the hyperperfusion syndrome caused three of five perioperative strokes (60%) and two of seven deaths (29%) in the entire endarterectomy population. Although rare, the hyperperfusion syndrome accounts for a significant percentage of the neurological morbidity and mortality following CEA.

Drug therapy of neurovascular disease

Recent advances in the prevention and pharmacotherapy of cerebrovascular disease have provided more favorable clinical outcomes. For the treatment of an acute ischemic stroke, the early use of thrombolytic agents can reduce the degree of brain damage while improving functional outcomes. However, trials evaluating various classes of other neuroprotective agents have not shown benefit to date. For the prevention of second stroke, the use of antiplatelet drugs, HMG-CoA reductase inhibitors, and angiotensin-converting enzyme inhibitors with a diuretic have shown benefit in reducing new events. In patients with underlying heart disease or atrial fibrillation, warfarin appears to be the drug of choice in preventing stroke. Early treatment of hemorrhagic stroke with calcium channel blockers can improve the functional outcome. Innovative therapies are now available for the treatment of migraine and vascular dementia. Primary prevention of stroke remains the optimal therapeutic strategy and includes treatment of systemic hypertension and hypercholesterolemia.

Cerebral hyperperfusion syndrome after carotid endarterectomy: predictive factors and hemodynamic changes

PURPOSE

It is believed that cerebral hyperperfusion syndrome (CHS) is caused by loss of cerebral autoregulation resulting from chronic cerebral ischemia and that factors including increased intraoperative cerebral blood flow, ipsilateral or contralateral carotid disease, and postoperative hypertension may cause CHS. We describe our experience with CHS, which diverges from published reports.

MATERIALS AND METHODS

From March 2000 to February 2002 we performed 455 carotid endarterectomy (CEA) procedures in 404 patients at our institution. CHS developed 1 to 8 days (mean, 3.2 +/- 2.5 days) postoperatively in 9 patients (2%), 6 women and 3 men, whose age ranged from 52 to 84 years (mean, 69 +/- 8 years). Indications for surgery in 8 patients without neurologic symptoms were ipsilateral internal carotid artery (ICA) stenoses ranging from 70% to 99% (mean, 80% +/- 7%); the remaining patient had an ipsilateral stroke, with good clinical recovery, 7 weeks before CEA. Only 1 patient had significant contralateral ICA stenosis (70%). However, 5 patients had undergone contralateral CEA within the previous 3 months. CHS symptoms were severe headache in 5 patients, seizures in 3 patients (1 stroke), and visual disturbance and ataxia in 1 patient. All 404 patients (455 cases) underwent intraoperative and early (2 weeks) postoperative carotid artery duplex scanning. The 9 patients with CHS also underwent carotid artery duplex scanning at the time of the neurologic event.

RESULTS

Mean intraoperative ICA volume flow (MICAVF) in the 9 CHS cases was not significantly different from that in the other 446 cases (170 +/- 47 mL/min and 182 +/- 81 mL/min, respectively). However, mean ICA volume flow (481 +/- 106 mL/min) and peak systolic velocity (PSV) (108 +/- 33 cm/s) for the 9 CHS cases measured at onset of symptoms were higher than those for the remaining 446 cases (267 +/- 87 mL/min and 80 +/- 26 cm/s, respectively) (P <.01). Of the 9 patients with CHS, only 3 had systolic blood pressures more than 160 mm Hg at onset of symptoms. Severity of ipsilateral and contralateral ICA stenoses was not significantly different between the 9 CHS cases and the remaining 446 cases.

CONCLUSIONS

These data do not corroborate the common belief that CHS occurs preferentially in patients with severe ipsilateral or contralateral carotid disease, increased intraoperative cerebral perfusion, or severe hypertension. Recently performed contralateral CEA (<3 months) appears to be predictive of CHS.

Three cases of hyperperfusion syndrome identified by daily transcranial Doppler investigation after carotid surgery

BACKGROUND

cerebral hyperperfusion syndrome (HS), occurs in 0.5-1% of patients undergoing carotid endarterectomy (CEA), and may result in intracerebral haemorrhage and death.

AIM

to diagnose HS by means of postoperative Transcranial Doppler (TCD).

METHODS

between 1998 and 2001 nearly all 112 patients who underwent CEA were monitored for four days postoperatively by Transcranial Doppler.

RESULTS

there were 3 patients with HS. All three showed TCD abnormalities hours before developing symptoms. One patient developed a full blown HS. Presumably, symptoms in the other two patients could be prevented by timely starting or restoring anti-hypertensive treatment.

CONCLUSION

daily TCD investigation in all patients undergoing CEA seems an effective strategy for the presymptomatic detection of HS.

Postoperative hyperperfusion syndrome in elderly patients with chronic subdural hematoma

BACKGROUND

Temporary acute agitated delirium is a frequent complication after surgery for chronic subdural hematoma (CSH) in elderly patients. To clarify the pathogenic mechanism underlying this complication, we measured cerebral blood flow before and after surgery in elderly patients with CSHs.

METHODS

Twenty-seven patients aged 75 years or older with unilateral CSH underwent treatment involving a single burr hole craniostomy with continuous catheter drainage. Cerebral blood flow was measured using single photon emission computed tomography 1 day before surgery, and at 1 hour and 24 hours after surgery. Acute agitated delirium was diagnosed by the characteristic behavioral abnormality.

RESULTS

SPECT imaging 1 hour after surgery demonstrated hyperperfusion in the cerebral cortex beneath the CSH in 14 patients (51.9%). Of these 14 patients, five showed acute agitated delirium a few hours after surgery that persisted for 10 to 12 hours. A hematoma was detected in the right hemisphere in all five patients. Hyperperfusion was significantly more intense in patients with acute agitated delirium both 1 hour and 24 hours after surgery than in patients (n = 9) without acute agitated delirium. Moreover, mean arterial blood pressure during the first postoperative hour was significantly higher in patients with acute agitated delirium.

CONCLUSION

In elderly patients with CSH, intense and prolonged hyperperfusion after surgery induces temporary acute agitated delirium. This postoperative hyperperfusion syndrome is exacerbated by hypertension.

Forebrain ischemia: effect on pharmacologically induced seizure thresholds in the rat

Seizures are common after severe cerebral ischemia. To examine the mechanisms underlying these seizures, we determined the impact of prior forebrain ischemia on the seizure thresholds of four convulsants with differing modes of action: lidocaine, pentylenetetrazol (PTZ), N-methyl-D-aspartate (NMDA), and picrotoxin. Anesthetized Sprague-Dawley rats were chronically instrumented with screw electrodes and vascular catheters, and then subjected to 10 min of forebrain ischemia, produced by carotid occlusion and hypotension (mean arterial pressure to 30 mmHg). Animals were then awakened. 6, 24 or 48 h later, groups of awake animals received intravenous infusions of the four drugs. The total dose of drug infused prior to either electrical seizures (lidocaine, PTZ, and picrotoxin) or tonic-clonic convulsions (all drugs) were noted. For each drug, a group of Sham animals (no ischemia) served as controls. There were markedly different patterns of changes in the convulsant thresholds for the drugs. For example, at 6 h post-ischemia, rats treated with lidocaine died before convulsing, while the threshold for PTZ increased by 86%. There was no change in the picrotoxin threshold at 6 h, but the dose of NMDA needed to induce tonic-clonic seizure activity was reduced by 70%. By 48 h, lidocaine and PTZ thresholds had returned to values similar to those in Shams, but the NMDA threshold had now increased to a value 62% greater than Sham. Ten minutes of cerebral ischemia is followed by a complex and changing pattern of susceptibility to chemical convulsants. Finding suggests that early post-ischemic seizures may be related to increased NMDA receptor sensitivity.

Epilepsy in patients with multiple sclerosis: radiological-clinical correlations

PURPOSE

To determine potential mechanisms of epilepsy in patients with multiple sclerosis (MS).

METHODS

Among 402 patients with clinically and radiologically defined MS, including de novo cases, presenting to the Neurology Service, University Hospital of Dijon, we identified 17 with epileptic seizures (4.25%). Among them, the percentage with partial seizures (50%) was greater than that in the reference population.

RESULTS

In most of the patients with MS, plaques were localized in the frontal region, associated with frontal and callosal atrophy, a frontal syndrome, and severe disability status (as assessed by a standard scale). Magnetic resonance imaging (MRI) showed numerous subcortical plaques. Seizures generally were well controlled with antiepileptic drugs (AEDs).

CONCLUSIONS

Our data suggest that the subcortical plaques of MS underlie seizure activity in patients with MS and epilepsy.

Diagnosis and monitoring of cerebral hyperfusion after carotid endarterectomy with single photon emission computed tomography: case report

OBJECTIVE AND IMPORTANCE

Focal neurological deficits after carotid endarterectomy may result from ischemia or hyperperfusion. The usefulness of single photon emission computed tomography (SPECT) for differentiating between these two mechanisms has not been previously emphasized.

CLINICAL PRESENTATION

An 83-year-old man experienced dysarthria and left-sided weakness immediately after undergoing endarterectomy of the right internal carotid artery. The results of computed tomography of the head were normal, and transcranial Doppler sonography showed symmetrically elevated velocities in both middle cerebral arteries. On the 1st postoperative day, the patient's deficits worsened in parallel with spontaneous increases in blood pressure, and blood pressure reduction with labetalol resulted in clinical improvement.

INTERVENTION

On the 2nd postoperative day, technetium-99-hexametazime SPECT demonstrated markedly increased flow in the right basal ganglia and inferior frontal cortex, confirming the diagnosis of cerebral hyperperfusion. The patient's deficits continued to improve with antihypertensive therapy, and SPECT performed 7 and 48 days after surgery showed gradual normalization of the focal hyperemia.

CONCLUSION

SPECT can be used to diagnose and monitor cerebral hyperperfusion after carotid endarterectomy and may be of particular value for differentiating hyperperfusion from ischemia when characteristic computed tomographic and transcranial Doppler sonographic findings are absent.

Periodic lateralized epileptiform discharges--a critical review

It is the purpose of this review to critically consider and organize the literature dealing with the ephemeral electroencephalographic (EEG) pattern periodic lateralized epileptiform discharges (PLEDs). Although the retrospective nature of these studies limits their ability to discuss accurately the clinical and pathophysiological aspects of this EEG entity, the available data strongly emphasize stroke as the dominant etiology and its high association with seizures. Recent evidence, particularly from functional neuroimaging studies, strongly suggests that PLEDs might reflect a key pattern for focal hyperexcitability in the penumbra zone of ischemic stroke. The authors prefer to consider PLEDs as an EEG signature of a dynamic pathophysiological state in which unstable neurobiological processes create an ictal-interictal continuum, with the nature of the underlying neuronal injury, the patient's preexisting propensity to have seizures, and the co-existence of any acute metabolic derangements all contributing to whether seizures occur or not. This review underlines the need for further sophisticated prospective controlled studies implementing early continuous EEG monitoring in order to contribute to an understanding of the incidence, dynamics, and relevance of this pattern.

Imaging studies of cerebral hyperperfusion after carotid endarterectomy. Case report

A case is reported of severe unilateral hemispheric edema and localized hemorrhage associated with seizures following endarterectomy of an ipsilateral high-grade carotid stenosis. Imaging studies including angiography, computerized tomography (CT), magnetic resonance imaging/angiography, and xenon-CT, suggested postoperative ipsilateral cerebral hyperperfusion. Cerebral hyperperfusion syndromes caused by a probable failure of vascular autoregulation are rare but potentially serious complications after endarterectomy. The literature on this type of complication is briefly reviewed, and the role of various imaging modalities in identification of the syndrome and in guiding management decisions is emphasized.

Seizures following carotid endarterectomy in patients with severely compromised cerebral circulation

OBJECTIVES

To determine the incidence of postoperative neurological complications following carotid endarterectomy in patients with severely compromised cerebral circulation.

DESIGN

Prospective open clinical study.

SETTING

Department of Vascular Surgery, University Hospital.

MATERIALS AND METHODS

We determined the incidence of postendarterectomy seizures related to haemodynamic impairment in terms of intraoperatively measured perfusion pressure in 151 patients undergoing 153 carotid endarterectomies.

MAIN RESULTS

Cerebral perfusion pressure index (ICA/CCA pressure ratio) was significantly reduced (25% or more) in 47% (55/118) of patients with 70-99% stenosis compared to 6% (2/35) of patients with 30-69% stenosis (p < 0.00005). Among the 57 haemodynamically compromised patients five developed seizures considered due to cerebral hyperperfusion five to seven days after surgery. The seizures were associated with headache in two, focal neurological deficits in four and hypertensive episodes in all cases. The symptoms remitted within 2 weeks and no patients suffered cerebral haemorrhage.

CONCLUSIONS

Seizures following correction of high grade stenoses causing severe pressure reduction may be more common than previously assumed. Patients at risk should be identified and postoperative blood pressure controlled meticulously.

Seizures due to multiple sclerosis: seven patients with MRI correlations

The MRI data of seven patients with clinically definite multiple sclerosis who developed epileptic seizures are presented. Six of these cases demonstrated new or enhancing lesions. Cerebral biopsy in one of these lesions confirmed inflammation with myelin breakdown products. Lesions implicated in the causation of seizures involved the cortex or subcortical area. In one patient, a new lesion was associated with EEG abnormalities which resolved as the lesion reduced in size. In three patients epileptic activity was the only clinical manifestation of disease. Large, unresolving lesions tended to be associated with continuing seizures.

Defective cerebrovascular autoregulation after carotid endarterectomy

Correction of high grade carotid artery stenosis may result in cerebral hyperperfusion because of defective vascular autoregulation. Thus, transcranial Doppler was used to determine mean arterial flow velocity (Vmean) of the middle cerebral artery in 95 patients before and after carotid endarterectomy. Attention was focused on postoperative episodes of ipsilateral headache and hypertension. Symptoms of cerebral hyperperfusion lasted for 3 (1.5-5) h (median and range) in nine patients, and for 12 (8-14) days in nine other patients. Of these later patients, two developed seizures on the 5th and 6th postoperative day, respectively. The mean pressure difference across the stenosis was 31 (0-63) mmHg in the symptomatic group (n = 18) as opposed to only 10 (0-60) mmHg in the asymptomatic group (n = 77) (p < 0.01). In the 18 patients with headache after surgery, ipsilateral Vmean increased to 177 (130-332)% of the preoperative value (p < 0.0001), while the contralateral Vmean remained unchanged. After blood pressure was reduced in symptomatic patients with labetalol, ipsilateral Vmean decreased from 92 (69-124) to 56 (32-93) cm s-1 (p < 0.0001) as systemic arterial pressure decreased from 101 (80-128) to 88 (60-103) mmHg, with no change in contralateral Vmean. Normalisation of Vmean via reduction of arterial pressure ended episodes of headache and seizure in symptomatic patients. Thus, in patients who developed post-endarterectomy hyperperfusion, these findings clearly demonstrated that ipsilateral middle cerebral artery mean flow velocity was pressure dependent. This substantiates the hypothesis of defective autoregulation in the ipsilateral hemisphere after carotid endarterectomy, and in turn demonstrates an immediate cessation of symptoms with reduction of arterial pressure even in normotensive patients.

Headache following carotid endarterectomy: a prospective study

The occurrence of headache in the 28 days following surgery was studied in 50 consecutive patients (14F and 36M, mean aged 70 years) who underwent carotid endarterectomy for atheromatous carotid stenosis. Thirty-one patients (62%) reported headache. Headache occurred in the first five days after surgery in 87% of cases. Its characteristics and temporal profile were highly variable but it was mostly bilateral (74%), mild or moderate (78%), requiring no treatment (77%). No correlation was found between the occurrence of headache and degree of stenosis, intraoperative characteristics and past history of headache. In none of our patients was severe ipsilateral headache, cerebral hyperperfusion syndrome, or cluster-like hemicrania encountered and only five patients met the IHS criteria for post-endarterectomy headache. Post-endarterectomy headache is frequent when specifically looked for and is therefore not a single entity. The present IHS criteria are unsatisfactory and should be modified accordingly.