Intracerebral haemorrhage after carotid endarterectomy

Intracerebral hemorrhage as a manifestation of cerebral hyperperfusion syndrome after carotid revascularization: systematic review and meta-analysis

BACKGROUND

Intracerebral hemorrhage (ICH) in the context of cerebral hyperperfusion syndrome (CHS) is an uncommon but potentially lethal complication after carotid revascularization for carotid occlusive disease. Information about its incidence, risk factors and fatality is scarce. Therefore, we aimed to perform a systematic review and meta-analysis focusing on the incidence, risk factors and outcomes of ICH in the context of CHS after carotid revascularization.

METHODS

We searched the PubMed and EBSCO hosts for all studies published in English about CHS in the context of carotid revascularization. Two reviewers independently assessed each study for eligibility based on predefined criteria. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and the PROSPERO register was made (register no. CRD42016033190), including the pre-specified protocol.

RESULTS

Forty-one studies involving 28,956 participants were deemed eligible and included in our analysis. The overall quality of the included studies was fair. The pooled frequency of ICH in the context of CHS was 38% (95% CI: 26% to 51%, I2 = 84%, 24 studies), and the pooled case fatality of ICH after CHS was 51% (95% CI: 32% to 71%, I2 = 77%, 17 studies). When comparing carotid angioplasty with stenting (CAS) with carotid endarterectomy (CEA), post-procedural ICH in the context of CHS was less frequent in CEA. ICH following CHS occurred less often in large series and was rare in asymptomatic patients. The most common risk factors were periprocedural hypertension and ipsilateral severe stenosis.

CONCLUSIONS

ICH as a manifestation of CHS is rare, more frequent after CAS and associated with poor prognosis. Periprocedural control of hypertension can reduce its occurrence.

Intraventricular Hemorrhage after Carotid Stenting

Purpose:

To report an important complication related to carotid stenting.

Methods and Results:

A 71-year-old man with symptomatic subtotal occlusion of the left internal carotid artery had a 30-mm lesion treated percutaneously with implantation of 2 stents. Although the procedure was completed satisfactorily, left intraventricular hemorrhage occurred 4 hours later, possibly related to hyperperfusion injury. The patient expired 30 days after the stent procedure. Preoperative single-photon emission computed tomography revealed severely reduced vasoreactivity in the affected territory after acetazolamide challenge.

Conclusions:

The risk of hyperperfusion injury must be considered and minimized in patients with significant restriction of regional vasoreactivity. We recommend that cerebral hemodynamic status be determined prior to carotid stenting.

Changes in middle cerebral artery velocity after carotid endarterectomy do not identify patients at high-risk of suffering intracranial haemorrhage or stroke due to hyperperfusion syndrome

OBJECTIVES

To determine if significant increases in middle cerebral artery velocity (MCAV) or pulsatility index (PI) during and immediately after carotid endarterectomy (CEA) were predictive of patients suffering a stroke due to the hyperperfusion syndrome (HS) or intracerebral haemorrhage (ICH).

METHODS

Transcranial Doppler (TCD) mean/peak MCAV and PI were recorded pre-operatively; pre-clamp; 1-min post-declamping; 10-min post-declamping and 30-min post-operatively. The study was divided into two time periods; Group 1 (1995-2007); where there was no formal guidance for managing post-CEA hypertension (PEH) and Group 2 (2008-2012); where written guidelines for treating PEH were available.

RESULTS

11/1024 patients in Group 1 (1.1%) suffered a stroke due to HS/ICH, compared to 0/426 patients (0.0%) in Group 2 (p = 0.02). In Group 1; intra-operative increases >100% in mean/peak MCAV and PI at 1 and 10-min post-clamp release had positive predictive values (PPV) of 1.2%, 6.3% and 20.0% and 2.9%, 8.0% and 16.6% respectively. Post-operatively; a >100% increase in mean and peak MCAV had a PPV of 6.3% and 2.7% respectively.

CONCLUSION

We were unable to demonstrate that significant increases in MCAV and PI were able to predict patients at increased risk of suffering a post-operative stroke due to HS or ICH. The provision of written guidance for managing PEH in Group 2 patients was associated with virtual abolition of ICH/HS.

Rapid formation of cerebral microbleeds after carotid artery stenting

Background

Recent studies reported that cerebral microbleeds (CMBs), i.e. small areas of signal loss on T₂*-weighted gradient-echo (GE) imaging, could develop rapidly after acute ischemic stroke. We hypothesized that CMBs rapidly emerge after carotid artery stenting (CAS).

Objective

We investigated the frequency of and predisposing factors for CMBs after CAS.

Methods

We retrospectively examined MRI before and after CAS in 88 consecutive patients (average age: 71.7 ± 7.2 years, average rates of carotid stenosis: 72.6 ± 12.8%) who underwent CAS for carotid artery stenosis between March 1, 2009, and September 30, 2010. We defined new CMBs as signal losses that newly appeared on the follow-up GE. We examined the association of new CMBs with demographics, risk factors, and baseline MBs.

Results

Among 88 patients, 18 (20.5%) had CMBs initially, and 7 (8.0%) developed new CMBs right after CAS. New CMBs appeared on the same side of CAS in all of the 7 patients. New CMBs appeared significantly more frequently in the CMB-positive group than in the CMB-negative one (22% vs. 4%, p = 0.03) on the pre-CAS MRI. Multivariate analysis also revealed that the presence of CMBs before CAS was an independent predictor of new development of CMBs after CAS (odds ratio: 8.09, 95% confidence interval: 1.39–47.1).

Conclusion

CMBs can develop rapidly after CAS, especially in patients with pre-existing CMBs. Since the existence of CMBs prior to CAS suggests a latent vascular damage which is vulnerable to hemodynamic stress following CAS, particular attention should be paid to the prevention of intracerebral hemorrhage due to hyperperfusion after CAS.

Clinical application of arterial spin-labeling MR imaging in patients with carotid stenosis: quantitative comparative study with single-photon emission CT

BACKGROUND AND PURPOSE

Arterial spin-labeling is an emerging technique for noninvasive measurement of cerebral perfusion, but concerns remain regarding the reliability of CBF quantification and clinical applications. Recently, an ASL implementation called QUASAR was proposed, and it was shown to have good reproducibility of CBF assessment in healthy volunteers. This study aimed to determine the utility of QUASAR for CBF assessment in patients with cerebrovascular diseases.

MATERIALS AND METHODS

Twenty patients with carotid stenosis underwent CBF quantification by ASL (QUASAR) within 3 days of performance of (123)I-iodoamphetamine-SPECT. CVR to acetazolamide also was assessed by ASL and SPECT. In surgically treated patients, the respective scans before and after the procedures were compared.

RESULTS

Regional CBF and CVR values measured by ASL were significantly correlated and agreed with those measured by SPECT (r(s) = 0.92 and 0.88, respectively). A Bland-Altman plot demonstrated good agreement between 2 methods in terms of CBF quantification. Furthermore, ASL could detect pathologic states such as hypoperfusion, impaired vasoreactivity, and postoperative hyperperfusion, equivalent to SPECT. However, ASL tended to overestimate CBF values especially in high-perfusion regions.

CONCLUSIONS

ASL perfusion MR imaging is clinically applicable and can be an alternative method for CBF assessment in patients with cerebrovascular diseases.

Effect of internal carotid artery reperfusion in combination with Tenecteplase on clinical scores and hemorrhage in a rabbit embolic stroke model

In the present study, we used a modification of the rabbit small clot embolic stroke model (RSCEM), a multiple infarct ischemia model to achieve reperfusion (REP) through the internal carotid artery (ICA) following small clot embolization. We determined if increasing regional cortical blood flow (RCBF) following an embolic stroke is beneficial to neurological outcome. We compared this to cerebral reperfusion induced by the administration of the thrombolytic Tenecteplase (TNK, 1.5 mg/kg, IV bolus) in the presence or absence of REP. In this study, we also measured the incidence of ICH following REP and thrombolytic treatment. Following embolization, RCBF was reduced to 48-55% of baseline. When REP was induced by removal of a CCA ligature, RCBF initially increased to 185% of baseline. REP (P(50)=1.18+/-0.43 mg) had no effect on embolization-induced behavior measured 24 h following embolization compared to control (P(50)=1.01+/-0.48 mg). However, TNK treatment (2-hours post-embolization) in the absence or presence of REP (initiated 2 h following embolization) significantly (p<0.05) increased the group P(50) to 2.92+/-0.55 mg and 2.42+/-0.40 mg, respectively. In addition, ICH was increased in the REP (42%, p<0.05) and REP-TNK (35%, p>0.05) group compared to either the control group (5.5%) or TNK group (10%). This study show that reperfusion of ICA can increase RCBF following embolization, but this is not associated with improved neurological outcome measured using quantal analysis. However, TNK administration significantly increased behavioral outcome when given 2 h following embolization; an increase that is not affected by combining TNK with REP.

Magnetic resonance imaging in patients with cerebral hyperperfusion and cognitive impairment after carotid endarterectomy

Object

Cerebral hyperperfusion after carotid endarterectomy (CEA) impairs cognitive function and is often detected on cerebral blood flow (CBF) imaging. The purpose of the present study is to investigate structural brain damage seen on magnetic resonance (MR) images obtained in patients with cerebral hyperperfusion and cognitive impairment after CEA.

Methods

One hundred and fifty-eight patients with ipsilateral internal carotid artery stenosis (≥ 70%) underwent CEA. Neuropsychological testing was performed preoperatively and at the 1st postoperative month. Cerebral blood flow was measured using single-photon emission computed tomography before, immediately after, and 3 days after surgery. Magnetic resonance imaging was performed before and 1 day after surgery. In patients with post-CEA hyperper-fusion (defined as a CBF increase ≥ 100% compared with preoperative values) on CBF imaging, MR images were also obtained on the 3rd postoperative day, the day on which hyperperfusion syndrome developed, and 1 month after the operation.

Results

The incidence of postoperative cognitive impairment was significantly higher in patients with post-CEA hyperperfusion on CBF imaging (12 [75%] of 16 patients) than in those without (6 [4%] of 142 patients; p < 0.0001). Only 1 of 5 patients with cerebral hyperperfusion syndrome developed reversible brain edema in the cerebral hemisphere ipsilateral to the CEA on MR images obtained on the day hyperperfusion syndrome occurred. However, postoperative cognitive impairment developed in all 5 patients with cerebral hyperperfusion syndrome regardless of the presence or absence of new lesions on MR images. In addition, postoperative cognitive impairment developed in 5 (45%) of 11 patients with asymptomatic cerebral hyperperfusion on CBF imaging despite the absence of new lesions on any postoperative MR images.

Conclusions

Although cerebral hyperperfusion syndrome after CEA sometimes results in reversible brain edema visible on MR imaging, postoperative cerebral hyperperfusion—even when asymptomatic—often results in impaired cognitive function without structural brain damage on MR imaging.

Probable blood-brain barrier disruption after carotid artery stenting

A 74-year-old man presented with prolonged reversible neurological deficits caused by internal carotid artery stenosis. He underwent carotid artery stenting (CAS) and developed persistent neurological deficits shortly following the intervention. Delayed gadolinium enhancement of the cerebrospinal fluid space on fluid-attenuated inversion recovery images indicated probable blood-brain barrier (BBB) disruption. Post-procedural perfusion-weighted magnetic resonance images could not demonstrate distinct areas of hyperperfusion or hypoperfusion. The neurological deficits probably resulted from BBB disruption secondary to sudden hemodynamic change occurring during CAS.

Intracranial hemorrhage associated with cerebral hyperperfusion syndrome following carotid endarterectomy and carotid artery stenting: retrospective review of 4494 patients

Object

Intracranial hemorrhage associated with cerebral hyperperfusion syndrome (CHS) following carotid endarterectomy (CEA) or carotid artery stenting (CAS) is a rare but potentially devastating complication. In the present study the authors evaluated 4494 patients with carotid artery stenosis who had undergone CEA or CAS to clarify the clinicopathological features and outcomes of those with CHS and associated intracranial hemorrhage.

Methods

Patients with postoperative CHS were retrospectively selected, and clinicopathological features and outcomes were studied.

Results

Sixty-one patients with CHS (1.4%) were identified, and intracranial hemorrhage developed in 27 of them (0.6%). The onset of CHS peaked on the 6th postoperative day in those who had undergone CEA and within 12 hours in those who had undergone CAS. Results of logistic regression analysis demonstrated that poor postoperative control of blood pressure was significantly associated with the development of intracranial hemorrhage in patients with CHS after CEA (p = 0.0164). Note, however, that none of the tested variables were significantly associated with the development of intracranial hemorrhage in patients with CHS after CAS. Mortality (p = 0.0010) and morbidity (p = 0.0172) rates were significantly higher in patients with intracranial hemorrhage than in those without.

Conclusions

Cerebral hyperperfusion syndrome after CEA and CAS occurs with delayed classic and acute presentations, respectively. Although strict control of postoperative blood pressure prevents intracranial hemorrhage in patients with CHS after CEA, there appears to be no relationship between blood pressure control and intracranial hemorrhage in those with CHS after CAS. Finally, the prognosis of CHS in patients with associated intracerebral hemorrhage is poor.

Preoperative cerebral hemodynamic impairment and reactive oxygen species produced during carotid endarterectomy correlate with development of postoperative cerebral hyperperfusion

BACKGROUND AND PURPOSE

The purpose of the present study was to determine whether preoperative cerebral hemodynamic impairment and reactive oxygen species produced during carotid endarterectomy (CEA) correlate with development of postoperative cerebral hyperperfusion.

METHODS

Concentrations of malondialdehyde-modified low-density lipoprotein (MDA-LDL), a biochemical marker of oxidative damage, were measured in serum samples obtained from 90 patients undergoing CEA for ipsilateral ICA stenosis (>70%). Serum samples were obtained from a venous catheter inserted into the ipsilateral jugular bulb before clamping of the internal carotid artery (ICA), 10 minutes after clamping of the ICA, and 5 and 20 minutes after declamping of the ICA. Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide were also measured using single-photon emission computed-tomography before CEA. In addition, CBF was measured postoperatively.

RESULTS

Hyperperfusion (CBF increase >100% compared with preoperative values) was observed immediately after CEA in 12 patients (13%). Logistic regression analysis demonstrated that reduced preoperative CVR (95% CIs, 1.053 to 1.453; P=0.0097) and an increase in MDA-LDL (calculated as a percentage of the preclamp values) after ICA declamping (95% CIs, 0.862 to 0.980; P=0.0098) were significantly associated with development of postoperative cerebral hyperperfusion among the variables tested. Ten of 11 patients with reduced preoperative CVR and increased MDA-LDL after ICA declamping developed post-CEA hyperperfusion, and 2 of these patients developed cerebral hyperperfusion syndrome.

CONCLUSIONS

Both preoperative cerebral hemodynamic impairment and reactive oxygen species produced during surgery correlate with development of cerebral hyperperfusion after CEA.

Case report: Aggressive blood pressure management for carotid endarterectomy hyperperfusion syndrome

PURPOSE

Cerebral hyperperfusion syndrome (CHS) is a rare but potentially devastating complication following cerebral revascularization. Management of CHS requires aggressive blood pressure control to prevent stroke and intracerebral hemorrhage. This case report documents a severe case of CHS, and outlines a successful outcome associated with aggressive blood pressure control.

CLINICAL FEATURES

A 67-yr-old gentleman, nine days post left carotid endarterectomy, required tracheal intubation and intensive care unit admission following seizures and acute right-sided weakness. A computed tomography scan and magnetic resonance imaging revealed significant vasogenic edema in the left middle cerebral artery territory, without evidence of infarction. The history and radiographic findings suggested CHS. As such, a systolic blood pressure target was set at 90-140 mmHg. This blood pressure parameter was lower than typically targeted following acute ischemic or hemorrhagic stroke. Rapid clinical improvements were seen by day five, and tight blood pressure control was maintained throughout. Repeat computed tomography and magnetic resonance imaging revealed improved edema and no evidence of infarct or hemorrhage.

CONCLUSION

Cerebral hyperperfusion syndrome is believed to occur following restoration of blood flow to a brain with impaired autoregulation due to chronic hypoperfusion. Massive brain edema and hemorrhage can result from higher pressures. Clinicians should be aware of this potential complication following cerebral revascularization procedures, and the importance of establishing blood pressure targets which are considerably lower than for other patients with similar clinical presentations.

Hemorrhagic Complications after Endovascular Therapy for Atherosclerotic Intracranial Arterial Stenoses

OBJECTIVE:

Hemorrhagic complications were analyzed in 106 procedures of 99 patients treated with percutaneous transluminal angioplasty (PTA) or stenting for intracranial arterial stenoses.

METHODS:

Ninety-nine patients with intracranial arterial stenosis were treated with PTA or stenting 106 times from January 1995 to December 2003. Fifty-seven patients had intracranial internal carotid artery stenosis, 23 had middle cerebral artery stenosis, and 19 had vertebrobasilar stenosis. Evaluation of hemodynamic compromise via single-photon emission computed tomography was performed 50 times for 50 patients before the treatment.

RESULTS:

Four hemorrhagic complications occurred in 106 procedures. Two of these cases involved intracerebral hemorrhage after PTA or stenting in the treated vascular territory 30 minutes and 16 hours after the treatment, respectively. One case showed subarachnoid hemorrhage, which appeared 6 hours after treatment. Hemodynamic compromise was found on single-photon emission computed tomography in these three cases. The last case with a hemorrhagic complication was a hemorrhagic infarction after recanalization of stent thrombosis, which appeared 3 days after stenting. Hyperperfusion syndrome was strongly suggested as the cause of hemorrhage in the two cases associated with intracerebral hemorrhage.

CONCLUSION:

The rate of hemorrhagic complication directly related to the procedure of PTA or stenting was 3%, and hyperperfusion syndrome was suggested as the cause of hemorrhage in two cases (2%), from the perspective of clinical characteristics and single-photon emission computed tomographic findings.

Reversible cerebral hyperperfusion syndrome after stenting of the carotid artery—Two case reports

Hyperperfusion syndrome can complicate carotid revascularization, be it endarterectomy or carotid artery stenting (CAS). Although extensive effort has been devoted to reducing the incidence of ischemic stroke complicating CAS, little is known about the incidence, etiology, and prevention strategies for hyperperfusion following CAS. We report two cases (female patients 72 and 81 years) presenting severe internal carotid stenosis (> 90%), who underwent presurgical and therapeutic intervention with CAS. Both patients developed hyperperfusion symptoms at 2 hours and at 30 minutes, respectively, following stenting, in both cases unilateral hyperperfusion was CCT confirmed. Case 1 was presenting with acute edema of the right hemisphere, case 2 with distended focal edema (left fronto-temporoparietally). Hyperperfusion syndrome and neurological symptoms retroceded in both cases (conservative therapy) and both patients returned to full activity (case 2 within 48 hours).

Cerebral hyperperfusion syndrome

Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy is characterised by ipsilateral headache, hypertension, seizures, and focal neurological deficits. If not treated properly it can result in severe brain oedema, intracerebral or subarachnoid haemorrhage, and death. Knowledge of CHS among physicians is limited. Most studies report incidences of CHS of 0-3% after carotid endarterectomy. CHS is most common in patients with increases of more than 100% in perfusion compared with baseline after carotid endarterectomy and is rare in patients with increases in perfusion less than 100% compared with baseline. The most important risk factors in CHS are diminished cerebrovascular reserve, postoperative hypertension, and hyperperfusion lasting more than several hours after carotid endarterectomy. Impaired autoregulation as a result of endothelial dysfunction mediated by generation of free oxygen radicals is implicated in the pathogenesis of CHS. Treatment strategies are directed towards regulation of blood pressure and limitation of rises in cerebral perfusion. Complete recovery happens in mild cases, but disability and death can occur in more severe cases. More information about CHS and early institution of adequate treatment are of paramount importance in order to prevent these potentially severe complications.

Postcarotid Endarterectomy Hyperperfusion or Reperfusion Syndrome

Background and Purpose— Hyperperfusion syndrome (HS) after carotid endarterectomy (CEA) has been related to impaired cerebrovascular autoregulation in a chronically hypoperfused hemisphere. Our aim was to provide new insight into the pathophysiology of the HS using magnetic resonance imaging (MRI) studies with diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI).

Methods— Five out of 388 consecutive patients presented 2 to 7 days after CEA, partial seizures (n=5), focal deficits (n=5), and intracerebral hemorrhage (n=3). In 4 patients, using sequential examinations, we identified vasogenic or cytotoxic edema by DWI; we assessed relative interhemispheric difference (RID) of cerebral blood flow (CBF) by PWI; and we measured middle cerebral artery mean flow velocities (MCA Vm) by transcranial Doppler (TCD).

Results— None of the patients presented pathological DWI hyperintensities, consistent with the absence of acute ischemia or cytotoxic edema. In 2 patients, we found an MRI pattern of reversible vasogenic edema similar to that observed in the posterior leukoencephalopathy syndrome. Middle cerebral artery (MCA) mean flow velocities (Vm) were not abnormally increased at any time. PWI documented a 20% to 44% RID of CBF in favor of the ipsilateral to CEA hemisphere.

Conclusions— HS can occur in the presence of moderate relative hyperperfusion of the ipsilateral hemisphere. MCA Vm values may not accurately reflect RID of CBF over the cortical convexity. We suggest that the hemodynamic pathogenetic mechanisms of the HS are more complicated than hitherto believed and that they may be more accurately described by the term “reperfusion syndrome.”

Postoperative cerebral hyperperfusion associated with impaired cognitive function in patients undergoing carotid endarterectomy

Object. Cognitive impairment occurs in 20 to 30% of patients following carotid endarterectomy (CEA). The purpose of the present study was to determine whether postoperative cerebral hyperperfusion is associated with impairment of cognitive function in patients undergoing that procedure.

Methods. Cerebral blood flow (CBF) was measured using single-photon emission computerized tomography scanning before and immediately after CEA and on the 3rd postoperative day in 92 patients with ipsilateral internal carotid artery stenosis of 70% or greater. Hyperperfusion post-CEA was defined as a 100% increase or greater in CBF compared with preoperative values. Neuropsychological testing was also performed preoperatively and at the 1-, 3-, and 6-month follow-up examinations.

At the 1-month postoperative neuropsychological assessment, 11 patients (12%) displayed evidence of cognitive impairment. In addition, the incidence of postoperative cognitive impairment in patients with post-CEA hyperperfusion (seven [58%] of 12 patients) was significantly higher than that in patients without post-CEA hyperperfusion (four [5%] of 80 patients; p < 0.0001). A logistic regression analysis demonstrated that post-CEA hyperperfusion was the only significant independent predictor of postoperative cognitive impairment. Of the seven patients in whom post-CEA hyperperfusion and cognitive impairment were identified 1 month postoperatively, four (including three patients with hyperperfusion syndrome) remained cognitively impaired at the 3- and 6-month follow-up examinations.

Conclusions. Postoperative cerebral hyperperfusion is associated with impairment of cognitive function in patients undergoing CEA. Furthermore, the development of hyperperfusion syndrome is associated with the persistence of postoperative cognitive impairment.

Pretreatment with the Free Radical Scavenger Edaravone Prevents Cerebral Hyperperfusion after Carotid Endarterectomy

OBJECTIVE:

Cerebral hyperperfusion syndrome after carotid endarterectomy (CEA) is a rare but potentially devastating complication. The purpose of the present study, which was not a randomized controlled trial but a case cohort study with historical control, was to determine whether pretreatment with a novel free radical scavenger, edaravone, could prevent occurrence of cerebral hyperperfusion after CEA.

METHODS:

Fifty patients with ipsilateral internal carotid artery stenosis (≥70%) underwent CEA with administration of edaravone before internal carotid artery clamping. Preoperative cerebral blood flow and cerebrovascular reactivity (CVR) to acetazolamide were assessed with single-photon emission computed tomography (SPECT). Cerebral blood flow also was measured immediately after CEA and on the 3rd postoperative day.

RESULTS:

Cerebral hyperperfusion (cerebral blood flow increase ≥100% compared with preoperative values) was revealed by SPECT performed immediately after CEA in only one patient (2%), who also exhibited reduced preoperative CVR. The incidence of post-CEA hyperperfusion as revealed by SPECT in the control group (51 CEA patients without administration of edaravone) was significantly higher (16%) (P= 0.0310, control versus treatment group). In addition, in a subgroup of patients with reduced preoperative CVR, the incidence of post-CEA hyperperfusion as revealed by SPECT in the edaravone group (7%) was significantly lower than that in the control group (67%) (P= 0.0029). Logistic regression analysis demonstrated that reduced preoperative CVR and absence of pretreatment with edaravone were significant independent predictors of post-CEA hyperperfusion as revealed by SPECT.

CONCLUSION:

Pretreatment with edaravone can prevent occurrence of cerebral hyperperfusion after CEA.

Intracerebral Haemorrhage Following Carotid Endarterectomy

OBJECTIVES

To determine risk factors for the development of hyperperfusion and intra-cerebral haemorrhage following carotid endarterectomy and formulate potential protocols for prevention.

METHODS

MEDLINE database search of the English language literature (1966-2002) was performed using the words 'cerebral haemorrhage', 'intracranial haemorrhage' and 'carotid endarterectomy'. Other articles were cross-referenced by hand.

RESULTS

There are no data from randomised trials confirming the significance of any single risk factor. The evidence suggests that the following may have a role: pre-operative hypertension, recent ipsilateral non-haemorrhagic stroke, previous ischaemic cerebral infarction, surgery for a > 90% ipsilateral internal carotid artery (ICA) stenosis, impaired cerebrovascular reserve, intra-operative haemodynamic or embolic ischaemia, post-operative hypertension, an ipsilateral increase of > or =175% in peak middle cerebral artery velocity (MCAV) and/or a > or =100% increase in pulsatility index.

CONCLUSIONS

A critical ICA stenosis with impaired cerebrovascular reserve resulting in maximal intracerebral vasodilatation and post-operative hyperperfusion (impaired autoregulation) appear to be central to the development of ICH. Appropriate pre-operative screening and post-operative monitoring in high risk patients might identify those who would benefit from manipulation of the haemodynamic events that appear to promote ICH.

Prediction and monitoring of cerebral hyperperfusion after carotid endarterectomy by using single-photon emission computerized tomography scanning

OBJECT

The purpose of this study was to determine whether the preoperative measurement of acetazolamide-induced changes in cerebral blood flow (CBF), which is performed using single-photon emission computerized tomography (SPECT) scanning, can be used to identify patients at risk for hyperperfusion following carotid endarterectomy (CEA). In addition, the authors investigated whether monitoring of CBF with SPECT scanning after CEA can be used to identify patients at risk for hyperperfusion syndrome.

METHODS

Cerebral blood flow and cerebrovascular reactivity (CVR) to acetazolamide were measured before CEA in 51 patients with ipsilateral internal carotid artery stenosis (> or = 70% stenosis). Cerebral blood flow was also measured immediately after CEA and on the 3rd postoperative day. Hyperperfusion (an increase in CBF of > or = 100% compared with preoperative values) was observed immediately after CEA in eight of 12 patients with reduced preoperative CVR. Reduced preoperative CVR was the only significant independent predictor of post-CEA hyperperfusion. Forty-three patients in whom hyperperfusion was not detected immediately after CEA did not exhibit hyperperfusion on the 3rd postoperative day and did not experience hyperperfusion syndrome. In two of eight patients in whom hyperperfusion occurred immediately after CEA, CBF progressively increased and hyperperfusion syndrome developed, but intracerebral hemorrhage did not occur. In the remaining six of eight patients in whom hyperperfusion was detected immediately after CEA, the CBF progressively decreased and the hyperperfusion resolved by the 3rd postoperative day.

CONCLUSIONS

Preoperative measurement of acetazolamide-induced changes in CBF, which is performed using SPECT scanning, can be used to identify patients at risk for hyperperfusion after CEA. In addition, post-CEA monitoring of CBF performed using SPECT scanning results in the timely and reliable identification of patients at risk for hyperperfusion syndrome.

Transcranial regional cerebral oxygen saturation monitoring during carotid endarterectomy as a predictor of postoperative hyperperfusion

OBJECTIVE

Hyperperfusion syndrome is a rare but potentially devastating complication that can occur after carotid endarterectomy (CEA). The purpose of this study was to determine whether intraoperative transcranial regional cerebral oxygen saturation (rSO(2)) monitoring via near-infrared spectroscopy could be reliably used to identify patients at risk for post-CEA hyperperfusion.

METHODS

rSO(2) was intraoperatively monitored for 50 patients undergoing CEA for treatment of ipsilateral internal carotid artery stenosis (>/=70%). Cerebral blood flow (CBF) was also assessed, with single-photon emission computed tomography, before and immediately after CEA.

RESULTS

Post-CEA hyperperfusion (CBF increase of >/=100%, compared with preoperative values) was observed for six patients. A significant linear correlation was observed between the rSO(2) increases immediately after declamping of the internal carotid artery and the CBF increases immediately after CEA (r(2) = 0.247, P = 0.0002). The sensitivity and specificity of the rSO(2) increases for detection of post-CEA hyperperfusion were 100 and 86.4%, respectively, with a cutoff point of 5%. A strong linear correlation was observed between the rSO(2) increases at the end of the procedure and the CBF increases immediately after CEA (r(2) = 0.822, P < 0.0001). Both the sensitivity and the specificity of the rSO(2) increases for detection of post-CEA hyperperfusion were 100% with a cutoff point of 10%. Hyperperfusion syndrome developed for one patient with post-CEA hyperperfusion, but intracerebral hemorrhage did not occur.

CONCLUSION

Intraoperative rSO(2) monitoring can reliably identify patients at risk for hyperperfusion after CEA.

Seizures after carotid endarterectomy: hyperperfusion, dysautoregulation or hypertensive encephalopathy?

OBJECTIVES

Presentation, management and outcome following seizure after carotid endarterectomy (CEA). MATERIALS AND DESIGN: Prospective audit.

RESULTS

Eight patients (0.8%) suffered a seizure (three bilateral) <30 days following 949 CEAs. Seizure was not associated with age, gender or presentation. Seven were treated hypertensives but four had labile BP pre-operatively. Five had severe bilateral carotid disease and four had vertebral/subclavian stenoses. Six had a >50% drop in middle cerebral artery blood flow velocity (MCAV) with clamping. Only three had >100% increase in MCAV with flow restoration. Five required treatment for post-operative hypertension. Two suffered seizures <36 hrs of CEA, the remainder were at 3-8 days. All eight had significantly elevated blood pressure at onset of seizures. Four underwent immediate MCAV monitoring and each was elevated. Emergency CT scanning/autopsy showed normal scans (n = 3), white matter oedema (n = 3), oedema and diffuse haemorrhage (n = 1), intracranial haemorrhage (n = 1). Seven developed a post-ictal neurological deficit (stroke = 5, TIA = 2). Overall, two patients either died or suffered a disabling stroke.

CONCLUSIONS

Post-CEA seizure was associated with adverse outcome. Most were labile hypertensives with severe bilateral carotid/vertebral disease. MCAV changes suggested poor collateral recruitment, but no consistent pattern of early hyperperfusion emerged. It remains uncertain whether high MCAVs and severe hypertension after seizure onset are cause or effect. Clinicians treating these patients in acute medical units were generally unaware of the "post-CEA hyperperfusion syndrome" and tended to treat the hypertension less aggressively.

Cerebral hyperperfusion after angioplasty and stenting of a totally occluded left subclavian artery: a case report

Cerebral hyperperfusion syndrome is documented after angioplasty of carotid and vertebral artery lesions. The authors report the first instance of cerebral hyperperfusion syndrome in the posterior cerebral circulation after angioplasty and stenting of a totally occluded left subclavian artery.

Increased cerebral blood flow after brain arteriovenous malformation resection is substantially independent of changes in cardiac output

Brain arteriovenous malformation (BAVM) resection can result in an acute increase in cerebral blood flow (CBF) of unclear etiology. This observational study investigated the relationship between changes in CBF and cardiac output (CO) in patients undergoing microsurgical resection of BAVMs. In 20 patients undergoing a BAVM resection during an isoflurane-based anesthesia, we measured CBF and systemic cardiovascular parameters immediately before and after BAVM resection. CBF was measured on the hemisphere ipsilateral to the lesions and on the contralateral side, using intravenous cold 133Xe washout. Cardiac output was measured using thermodilution technique via a pulmonary artery catheter. There was an increase in global CBF after resection (25 +/- 8 versus 31 +/- 13 mL/100 g/min, preresection versus postresection, mean +/- SD, P =.002), ipsilateral CBF (25 +/- 8 versus 31 +/- 13 mL/100 g/min, P =.002), and contralateral CBF (24 +/- 7 versus 30 +/- 13 mL/100 g/min, P =.003). There was no change in CO, mean systemic arterial pressure, central venous pressure, or pulmonary artery diastolic pressure. The change in CBFGLOBAL was not correlated with changes in CO (r =.154, P =.517). BAVM resection resulted in global increases in CBF that was not substantially related to changes in CO or other systemic parameters.

An observational study of pre-operative transcranial Doppler examinations to predict cerebral hyperperfusion following carotid endarterectomies

The objective of this observational study was to determine whether pre-operative transcranial Doppler measurements could identify patients at risk for early cerebral hyperperfusion following carotid endarterectomies. Fifty-five patients (mean age 64.4 years) with symptomatic internal carotid artery stenosis were included. Pre-operative transcranial Doppler measurements included middle cerebral artery blood flow velocities at normocapnia, pulsatility indices and estimation of the cerebro-vascular reserve capacity ipsilateral to the internal carotid artery stenosis. The percentage change in blood flow velocities before and at the end of the procedure was calculated. Early cerebral hyperperfusion was defined as an increase of mean blood flow velocity of more than 100% at the end of the carotid endarterectomy. Early cerebral hyperperfusion was observed in 9.2%. Cerebral hyperperfusion was seen in patients with a subtotal carotid artery stenosis in combination with reduced pre-operative blood flow velocity and pulsatility. The post-operative stroke incidence in patients with an early cerebral hyperperfusion was tenfold higher compared to patients who did not experience early hyperperfusion. A prospective clinical trial is warranted to determine whether transcranial Doppler parameters can be used to indicate patients at risk for reperfusion strokes following carotid endarterectomies.

Early carotid endarterectomy for critical carotid artery stenosis after thrombolysis therapy in acute ischemic stroke in the middle cerebral artery

BACKGROUND AND PURPOSE

Tissue plasminogen activator (tPA) has been shown to be effective for acute ischemic stroke. However, if a high-grade cervical carotid stenosis remains despite tPA therapy, patients are at risk for recurrent stroke. Carotid endarterectomy (CEA) has been shown to be effective in symptomatic patients with high-grade cervical carotid stenosis in reducing the risk of stroke, but it is unknown whether CEA can be performed safely after tPA thrombolysis. We describe our experience with 5 patients who underwent early (<48 hours) CEA for residual high-grade cervical carotid stenosis after thrombolytic therapy for acute ischemic stroke in the middle cerebral artery territory.

METHODS

All patients had a critical (>99%) carotid artery stenosis on the symptomatic side after tPA therapy. All patients received intravenous tPA; 3 patients also received intra-aortic tPA. Three patients received intravenous heparin infusion immediately after administration of tPA. All patients showed marked improvement in their National Institutes for Health Stroke Scale scores after treatment with tPA. CEA was then performed within 45 hours (6 hours in 1 patient, 23 hours in 2, 26 hours in 1, and 45 hours in 1).

RESULTS

All 5 patients underwent successful CEA. There were no complications related to surgery. At discharge, 2 patients had a normal examination, and the remaining patients had mild deficits. In a long-term follow-up of 5 to 22 months, no patient had a recurrent cerebrovascular event.

CONCLUSIONS

Early CEA can be performed safely and successfully in patients after tPA treatment for acute ischemic stroke in appropriately selected patients.

Cerebral vasoreactivity and internal carotid artery flow help to identify patients at risk for hyperperfusion after carotid endarterectomy

BACKGROUND AND PURPOSE

Hyperperfusion syndrome is a rare but potentially devastating complication after carotid endarterectomy (CEA). The aim of this study was to investigate whether preoperative measurement of cerebral vasoreactivity (CVR) and intraoperative measurement of internal carotid artery (ICA) flow could identify patients at risk for hyperperfusion after CEA.

METHODS

For 26 patients with unilateral ICA stenosis >/=70%, cerebral blood flow (CBF) and CVR were investigated before and 1 month after CEA, with resting and acetazolamide-challenge single-photon emission CT. CBF on the first postoperative day was also measured. ICA flow was measured before and after reconstruction by electromagnetic flowmeter during surgery.

RESULTS

Ipsilateral CBF on the first postoperative day significantly increased relatively (56.6+/-53.2%) as well as absolutely (37.9+/-8.8 to 57.7+/-18.0 mL/100 g per minute) in the reduced CVR group (CVR <12%) but not in the normal CVR group (CVR >/=12%) (10.3+/-15.5% and 40.6+/-7.9 to 43.9+/-5.7 mL/100 g per minute, respectively). One month later, this difference almost disappeared. Two patients showed ipsilateral CBF increase of >/=100%. A significant association of intracerebral steal with hyperperfusion (CBF increase >/=100%) on the first postoperative day was also observed. ICA flow increase after reconstruction significantly correlated with CBF increase on the first postoperative day in the reduced CVR group but not in the normal CVR group. The threshold of ICA flow increase for hyperperfusion was estimated to be 330 mL/min in the reduced CVR group.

CONCLUSIONS

Single-photon emission CT with acetazolamide challenge and ICA flow measurement during surgery could identify patients at risk for hyperperfusion after CEA, in whom careful monitoring and control of blood pressure should be initiated even intraoperatively.

Carotid endarterectomy in diabetic patients

OBJECTIVE

The purpose of the current study was to identify the possible short- and long-term effects of diabetes on the outcome of carotid endarterectomy.

METHODS

Medical records were reviewed for 781 carotid endarterectomies (in 734 patients) performed by the same vascular surgeon in a university medical center between January 1994 and December 1998. Patients were divided two groups: those with diabetes (n = 181 patients; 193 operations) and those without diabetes (n = 553; 588 operations). The two groups were similar with respect to mean age, male-female ratio, and contralateral lesions. The only significant differences were a higher prevalence of peripheral vascular disease and dyslipidemia in the diabetic group and a higher prevalence of hemispheric transient ischemic attacks among the nondiabetic patients. Carotid color duplex ultrasound scan had been performed in all patients, and in 56 patients from the diabetic group and 56 patients from the nondiabetic group (matched for age, sex, and contralateral lesions), the distal extension of the lesion from the carotid bifurcation had also been defined. Both of these subgroups were fully representative of their respective groups of origin. Carotid endarterectomy was performed after the induction of general anesthesia; electroencephalographic monitoring was continuous.

RESULTS

Except for the significantly higher prevalence of calcified plaques in the diabetic patients (P <.0001), the characteristics of the carotid disease in the two groups were similar. In the 56-member subgroups, 73.2% of the diabetic and 35.7% of the nondiabetic patients (P <.0001) had lesions extending more than 2 cm beyond the carotid bifurcation. Mean length of plaque beyond the bifurcation was 2.3 +/- 0.09 cm for the diabetic and 1.7 +/- 0.08 cm for the nondiabetic patients (P <.0001). Diabetes was the only factor significantly correlated with plaque length. In the diabetic subgroup, surgery was characterized by significantly longer carotid arteriotomies (P =.03) and clamp times (P <.003). Operative mortality was 1.5% in the diabetic group (2 myocardial infarctions + 1 stroke) and 0.5% in the nondiabetic group (1 myocardial infarction + 2 strokes; P value not significant); stroke rates were 1.5% (3 major strokes) and 0.5% (2 major strokes + 1 minor stroke), respectively (P = not significant). Long-term survival (5 years) was not significantly lower among the diabetic patients.

CONCLUSIONS

Diabetes mellitus does not seem to significantly increase the surgical risk for carotid endarterectomy. The presence of more extensive plaques has no significant effect on the results of surgery.

Cerebral hyperperfusion syndrome after percutaneous transluminal stenting of the craniocervical arteries

OBJECTIVE

Cerebral hyperperfusion syndrome is a recognized complication of carotid endarterectomy, with a reported incidence of 0.3 to 1.2%. The incidence of cerebral hyperperfusion after endovascular revascularization procedures of the craniocervical arteries remains unknown. We evaluated the incidence of cerebral hyperperfusion syndrome in our endovascular revascularization series. To our knowledge, there are no previous studies evaluating the incidence of hyperperfusion syndrome after percutaneous transluminal angioplasty/stenting.

METHODS

Between March 1996 and February 2000, 140 patients underwent percutaneous transluminal angioplasty/stenting of the craniocervical arteries at our institution. In all patients, selective bilateral arteriography of the carotid and vertebral arteries was performed to document the sites of craniocervical stenosis and collateral blood flow and the results of the endovascular revascularization procedure. We then reviewed all pertinent medical records, arteriographic films, and sectional imaging studies to determine the incidence of cerebral hyperperfusion in this series.

RESULTS

Seven patients (5.0%) developed clinical or radiological manifestations of cerebral hyperperfusion. In the target group, percutaneous transluminal stenting achieved a 90 to 100% reduction in stenotic lesions (mean stenosis, 91%) of the carotid (n = 5) and vertebral (n = 2) arteries. All seven patients remained neurologically stable immediately after treatment. There was delayed development of clinical and radiographic findings, suggestive of cerebral hyperperfusion. Six patients showed evidence of ipsilateral hemispheric edema, including two patients who developed intracranial hemorrhage (one parenchymal, one parenchymal and subarachnoid) documented by computed tomographic brain scans. Symptoms resolved within 72 hours in the four patients without hemorrhage. The two patients with hemorrhage recovered during a more protracted period (range, 3 wk to 6 mo). There were no long-term sequelae or deaths during a cumulative follow-up of 84 months (mean follow-up, 12 mo).

CONCLUSION

Hyperperfusion syndrome is an uncommon but potentially serious complication of extracranial and intracranial angioplasty and stenting procedures. The clinical manifestations are similar to hyperperfusion syndrome after carotid endarterectomy; however, the prevalence may be greater in the high-risk cohort commonly referred for endovascular treatment. Our findings suggest that patients undergoing endovascular stenting procedures should be closely monitored for evidence of hyperperfusion, with careful monitoring of blood pressure, heart rate, and anticoagulation. Further research is needed to confirm that cerebral hyperperfusion is the pathogenesis of this condition.

Intraventricular hemorrhage after carotid stenting

PURPOSE

To report an important complication related to carotid stenting.

METHODS AND RESULTS

A 71-year-old man with symptomatic subtotal occlusion of the left internal carotid artery had a 30-mm lesion treated percutaneously with implantation of 2 stents. Although the procedure was completed satisfactorily, left intraventricular hemorrhage occurred 4 hours later, possibly related to hyperperfusion injury. The patient expired 30 days after the stent procedure. Preoperative single-photon emission computed tomography revealed severely reduced vasoreactivity in the affected territory after acetazolamide challenge.

CONCLUSIONS

The risk of hyperperfusion injury must be considered and minimized in patients with significant restriction of regional vasoreactivity. We recommend that cerebral hemodynamic status be determined prior to carotid stenting.

Transcranial Doppler monitoring during carotid endarterectomy helps to identify patients at risk of postoperative hyperperfusion

OBJECTIVES

to investigate whether transcranial Doppler (TCD) monitoring can identify patients at risk of hyperperfusion, and whether active postoperative treatment of selected patients decreases the risk of intracerebral haemorrhage (ICH).

DESIGN

a case cohort study of 688 patients undergoing carotid endarterectomy (CEA) with intraoperative TCD monitoring.

METHODS

sixty-two patients (9%) fulfilled the TCD criteria for hyperperfusion, i.e. >100% increase of peak blood flow velocity or pulsatility index of the middle cerebral artery, compared to preclamp baseline values. In these patients, blood pressure was closely monitored and controlled postoperatively.

RESULTS

postoperatively, seven of these patients (11%) exhibited clinical signs or symptoms of hyperperfusion but no cerebral haemorrhage (ICH). This is a significantly better outcome (p <0.005) compared to a 2% incidence of ICH after CEA in previous years in our hospital.

CONCLUSIONS

patients at risk of hyperperfusion syndrome after CEA can be identified intraoperatively by TCD monitoring. In these selected patients, immediate and adequate postoperative treatment of hypertension results in a decreased risk of intracerebral haemorrhage.

Timing of carotid endarterectomy after stroke

BACKGROUND

Timing of carotid endarterectomy after stroke in a patient with a fixed neurological deficit remains an important but unresolved question. Early surgery has been associated with cerebral hemorrhage and infarct extension. Delayed endarterectomy exposes the patient to recurrent stroke and carotid occlusion. This review investigates the hypothesis that timing of surgery after stroke influences outcome and complications.

SUMMARY OF REVIEW

This analysis critically evaluates peer-reviewed reports that retrospectively examined outcome after surgery performed "early" and "late" after stroke. The basis for intracerebral hemorrhage after endarterectomy is discussed. Clinical features that influence outcome are investigated.

CONCLUSIONS

Patients undergoing carotid endarterectomy are considered a heterogeneous group based on the following features: presence of low density on cranial CT, vascular territory of the infarct, brain shift, and level of consciousness. While critical review of these retrospective studies suggests that some patients with an acute stroke can safely undergo endarterectomy shortly after the diagnosis is made, direct answers to these questions of timing of endarterectomy after stroke are best addressed by prospective studies. Nevertheless, the present review provides a basis for decision making in certain patients and for the design of future investigations.

Application of transcranial Doppler sonography to evaluate cerebral hemodynamics in carotid artery disease. Comparative analysis of different hemodynamic variables

BACKGROUND AND PURPOSE

Transcranial Doppler sonography in combination with manipulation of cerebral resistance vessels is widely used to screen patients with suspected intracranial hemodynamic disturbances. Maximal flow velocity (Vmax), mean flow velocity (Vmean), cerebral pulsatility index (CPi), and cerebral resistance index (CRi) have all been used to describe cerebral hemodynamics. The present study examined CO2 reactivity of the above hemodynamic variables with respect to its variability between different age groups and its capability to discriminate between normal and abnormal findings.

METHODS

Absolute and relative CO2 reactivity of Vmax, Vmean, CRi, and CPi were determined in both hemispheres in 30 young and 37 elderly control subjects and in 245 consecutive patients with strictly unilateral symptomatic (n = 101) or asymptomatic (n = 144) carotid artery disease (> 80% stenosis or occlusion).

RESULTS

Hemispheric reactivities of Vmean, CRi, and CPi were significantly age dependent. Hemispheric Vmax reactivity and interhemispheric differences of individual reactivities (except absolute CPi reactivity) did not vary with age and could therefore be used to define normal values. Patient classification according to these values revealed different frequencies of subjects with pathological findings (3% for hemispheric Vmax reactivity, 5% to 7% for interhemispheric differences of Vmax or Vmean reactivity, 39% and 45% for interhemispheric differences of relative CRi and CPi reactivity, respectively).

CONCLUSIONS

Hemispheric reactivities are less suitable to evaluate cerebral hemodynamics than interhemispheric differences, since most of the latter do not vary with age. However, interhemispheric differences vary with respect to their discriminatory power. Power is low for interhemispheric differences of Vmax and Vmean reactivity, since the corresponding frequencies of abnormal findings do not differ from the 5% frequency expected in the reference population (reference range defined as mean +/- 2 SD). With respect to the discriminatory power, interhemispheric differences of relative CRi and CPi reactivity may be superior to other parameters.

Carotid endarterectomy--when to do it, how to do it?

With the completion of the major carotid endarterectomy trials the indications for this procedure can be defined. The procedure, if done by experienced teams, has been shown to improve the chance of stroke free survival in symptomatic and asymptomatic patients with a high-grade stenosis of the internal carotid artery. In asymptomatic patients the risk reduction gained by prophylactic carotid endarterectomy may be small in relation to the risk of coincident factors particularly coronary artery disease. The benefit gained by carotid endarterectomy depends closely on the risk of the procedure itself, and a single little flaw during the management can annulate the benefit of the operation in asymptomatic patients. There are still considerable controversies with regard to peri-operative management and surgical technique, e.g., the necessity of routine pre-operative arteriography has recently been questioned. Quality control programmes become a requirement with the publication of performance standards for carotid endarterectomy. According to a consensus of the American Heart Association, the surgical morbidity/mortality must be less than 6% for symptomatic carotid lesions and less than 3% for asymptomatic lesions. The present review discusses the steps of the pre-operative work-up, the procedure itself and the post-operative management with the aim to identify accepted safety standards as well as areas of uncertainty.

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.

Prediction of intracerebral haemorrhage after carotid endarterectomy by clinical criteria and intraoperative transcranial Doppler monitoring

Intracerebral haemorrhage is a serious complication after carotid endarterectomy. We tried to identify predictors of this event. Two-hundred-and-thirty-three operations were selected from a total of 280 because of reliable intraoperative transcranial Doppler data with regards to the increase of peak blood flow velocities and pulsatility indices in the ipsilateral middle cerebral artery after release of the internal carotid artery cross-clamp. We also recorded the occurrence of unilateral throbbing headache or hypertension after the operation. Five patients developed an intracerebral haemorrhage after the operation. Seventeen patients developed headache or hypertension after surgery, four of whom developed an intracerebral haemorrhage (p < 0.001; Fisher's exact test). The positive predictive value of headache, hypertension, or both, for intracerebral haemorrhage was 24% (diagnostic gain 22%). The negative predictive value, sensitivity and specificity were 99, 80 and 94%, respectively. The increase of peak blood flow velocities and pulsatility indices in patients who developed intracerebral haemorrhage was significantly higher than in patients who did not (p < 10(-5); one-way ANOVA). With appropriate cut-off levels for the increase of peak blood flow velocities (> or = 175% increase) or pulsatility indices (> or = 100% increase) after release of the cross-clamps, the positive predictive value of intraoperative transcranial Doppler for intracerebral haemorrhage was 100% (diagnostic gain 98%). The negative predictive value, sensitivity and specificity were 99, 80 and 100%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Prediction of intracerebral haemorrhage after carotid endarterectomy by clinical criteria and intraoperative transcranial Doppler monitoring: results of 233 operations

OBJECTIVE

Identification of predictors of intracerebral haemorrhage after carotid endarterectomy.

DESIGN

Retrospective comparison of patients who developed intracerebral haemorrhage and patients who did not, with special attention to intraoperative transcranial Doppler monitoring of the ipsilateral middle cerebral artery and postoperative signs and symptoms of hypoperfusion.

SUBJECTS AND MATERIALS

Two-hundred and thirty-three patients were studied with regard to the increase of peak blood flow velocities and pulsatility indices after endarterectomy and to the occurrence of unilateral throbbing headache or hypertension.

RESULTS

Intracerebral haemorrhage occurred in five cases. Seventeen patients complained of headache or showed hypertension, four of whom developed an intracerebral haemorrhage (p < 0.001; Fisher's exact test). The positive predictive value of headache, hypertension, or both, was 24% (diagnostic gain 22%). The negative predictive value, sensitivity and specificity were 99, 80 and 94%, respectively. The increase of peak blood flow velocities and pulsatility indices in patients who developed intracerebral haemorrhage was significantly higher than in patients who did not (p < 10(-5); one-way ANOVA). When cut-off levels for the increase of peak blood flow velocities and pulsatility indices were set to 175 and 100%, respectively, the positive predictive value of intraoperative transcranial Doppler was 100% (diagnostic gain 98%). The negative predictive value, the sensitivity and specificity were 99, 80 and 100%, respectively.

CONCLUSION

An increase of peak blood flow velocity > or = 100% or pulsatility index > or = 100% after declamping predicts intracerebral haemorrhage more accurately than the occurrence of headache or hypertension. Transcranial Doppler monitoring can be used to identify patients at risk for intracerebral haemorrhage, in whom control of blood pressure and modest degrees of anticoagulation may be appropriate.

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.

Hyperperfusion syndrome after carotid endarterectomy. CT changes

This article describes the CT scans of two patients who, following carotid endarterectomy, developed headache and seizures suggestive of hyperperfusion syndrome. Their CT scans demonstrated ipsilateral mass effect and white matter hypodensity. One patient progressed to hemorrhage and died. Although infarction is described as the commonest neurologic event to occur after carotid endarterectomy, autopsy or cerebral blood flow studies in these patients suggests that the changes were due to hyperperfusion rather that infarction.

Site and pathogenesis of infarcts associated with carotid endarterectomy

We analyzed perioperative strokes in 658 carotid endarterectomies with the purpose of explaining the pathogenesis from the morphologic aspect of the infarct on cerebral computed tomograms. All endarterectomies were performed with continuous electroencephalographic monitoring. Of the 42 ischemic strokes (6.4% of all endarterectomies), 34 could be studied. Seven infarcts were hemodynamically induced (five watershed infarcts, two patients with bilateral ischemia); all seven occurred during surgery. Twenty-three of the remaining 27 infarcts were within the territory of the middle cerebral artery (20) or anterior cerebral artery (three) and were probably of thromboembolic origin; 13 of these 23 occurred during surgery (57%). If intraoperative stroke was heralded by permanent electroencephalographic changes, these were not related to the moment of cross-clamping. In four patients the computed tomogram was normal. We believe these facts favor the hypothesis that thromboembolism is the most important factor in the pathogenesis of perioperative stroke associated with carotid endarterectomy under conditions of optimal cerebral monitoring.

Haemodynamic evaluation of carotid artery disease

Cerebral ischaemia in the region of an internal carotid artery (ICA) stenosis may be caused by embolism or cerebral hypoperfusion. A severe ICA stenosis may be well compensated by collateral blood supply, however, in some patients the capacity of the collateral blood supply is insufficient. Studies evaluating therapeutic modalities or natural history of carotid artery disease should therefore include a test capable of assessing cerebral haemodynamics. However, most studies, invasive as well as non-invasive, have focused on the ability of the test to diagnose the ICA lesions itself, rather than the haemodynamic changes induced by the stenosis. This paper reviews non-invasive methods for haemodynamic evaluation of carotid artery disease. Haemodynamic evaluation of ICA stenoses may be performed accurately by different techniques. Analysis of Doppler waveforms obtained distal to the ICA lesion and CBF reactivity tests may identify patients with severe reduction in ICA perfusion pressure. Periorbital Doppler examination and OPG identifies ICA lesions causing minor pressure gradients, however, they are unable to discriminate between minor and moderate to severe pressure reduction. Transcranial Doppler examination may prove to be useful in haemodynamic assessment of ICA stenoses, but, this remains to be evaluated. Presently, in addition to direct evaluation of the carotid arteries, we use a combination of periorbital Doppler examination and analysis of distal ICA waveforms. In cases of an ICA stenosis and orthograde flow any severe pressure reduction may be ruled out. In cases of inverted flow, analysis of distal ICA waveforms may identify patients with severe reduction in ICA perfusion pressure.

Hemodynamic significance of internal carotid artery disease

Neurologic symptoms in the region of an internal carotid artery stenosis are considered to be embolic in most instances. Only in a subgroup has carotid occlusive disease with impairment of the collateral supply, caused a state of hemodynamic failure with marked reduction of perfusion pressure. Though unproven, it is reasonable to assume that without surgical intervention, the risk is higher than average for patients with hemodynamic failure. Equally, should there be any postoperative improvement of cerebral blood flow or neurologic deficits, it should be looked for in this group. Thus, it is necessary to distinguish those with low perfusion pressure from the population of patients with carotid artery disease. Preoperative clinical evaluation and direct visualization of the carotid bifurcation should be supplemented by indirect physiological tests which allow assessment of collateral perfusion. Examination of periorbital flow direction or oculoplethysmography could be used as a screening procedure. Negative tests most certainly rule out any severe pressure gradient across the stenosis, irrespective of the luminal reduction. A positive result, on the other hand, should be further quantified since most indirect tests become positive at relatively small pressure gradients. Studies of cerebral blood flow at rest and during cerebral vasodilation makes it possible to identify patients with severe reduction of cerebral perfusion pressure. Such hemodynamic failure of one hemisphere may be identified in most cases by a conventional non-invasive xenon-133 technique and stationary detectors. Smaller focal regions of hypoperfusion may be identified by computer emission tomography, either by the detection of single-photon emission or by paired detection of annihilation photons. Endarterectomy does improve cerebral hemodynamics in terms of increased flow through the reconstructed vessel and elimination of pressure gradients. The cerebral blood flow, though remains unchanged in the majority of patients, at least when measured at baseline. Only in those patients with a reduction in perfusion pressure can a significant improvement in baseline flow occur. Flow reserve determined by cerebral vasodilation, however, will improve in most patients with hemodynamic failure. In addition, some patients in the low-pressure group develop marked, but temporary, hyperperfusion after reconstruction of very high grade carotid stenosis. This is considered a result of chronic low perfusion pressure with subsequent loss of autoregulation, and autoregulatory control is first regained after some days.(ABSTRACT TRUNCATED AT 400 WORDS)