Acute Carotid Occlusion Research Articles

Bilateral internal carotid artery occlusions resulting in near total acute brain infraction

Acute bilateral acute carotid arteries occlusion is a very rare condition. We describe a patient with initial right middle cerebral artery syndrome who developed coma and quadriplegia 1 h after thrombolysis with intravenous tPA and was found to have bilateral cervical internal carotid artery occlusion.

Brain Injury Secondary to Carotid Intervention

Causes of brain injury during endovascular carotid intervention are protean. Mechanisms of injury include embolic and hemodynamic events, acute carotid occlusions occurring through a variety of means, and the relatively rare contrast-induced encephalopathy. Embolic injury may result from micro- and macroembolization and most commonly causes ischemic stroke when sufficiently severe. Hemodynamic injury may proceed from hemodynamic depression and hypoperfusion (which may result in watershed infarction) or the hyperperfusion syndrome, which may, if severe, result in hemorrhagic stroke. Embolic and dynamic causes of stroke may either occur intraprocedurally or at a variable time after stent placement and may be co-related. Impaired clearance of emboli due to relative hypoperfusion may exacerbate their clinical relevance. Other causes of stroke include acute carotid occlusions, which most commonly occur procedurally due to flow-limiting spasm, acute dissection, and, if a filter-type cerebral protection device has been used, filter occlusion due to a large trapped embolic load. These scenarios may result in stroke if not recognized and dealt with appropriately. Acute stent thrombosis may occur within 24 hours of the procedure as a result of adverse hemodynamic factors or suboptimal patient response to procedural heparin and antiplatelet agents, or it may occur after the procedure, again perhaps as a result of suboptimal response to antiaggregate drugs.

Revascularization Procedure Mainly by Suction Thrombectomy for Acute Cervical Carotid Occlusion

In many cases, the prognosis for acute cervical carotid artery occlusion is poor. However, a standard treatment for the acute stage is not yet established. We report here the results of eight consecutive patients (mean age 71.5 years old) in which revascularization mainly by suction thrombectomy was performed under proximal protection during the acute phase. The occlusion sites were the intracranial internal carotid artery in five patients, tandem lesions of the internal carotid origin and intracranial vessel in two patients, and the common carotid artery in one patient. In addition, the subjects who received the treatment had an extent of infarction in MRI/DWI that was 1/3 or less of the internal carotid artery territory. The mean time from the onset to treatment commencement was 7.25 hours (2-28 hours). For the endovascular treatment, a guiding catheter with a balloon was used for proximal protection of the carotid artery. Revascularization was performed mainly by suction thrombectomy, and if a stenosed lesion was observed, PTA/stenting was added. Local fibrinolysis was not performed in combination with the above procedure. The treatment results were complete recanalization in three patients and partial recanalization in three patients. However, recanalization was not achieved in two patients. No hyperfusion syndrome or hemorrhagic infarction was observed postoperatively. All four patients in whom thrombi were successfully aspirated had occlusions proximal to the ophthalmic artery branch. In three of these four patients, complete recanalization was achieved. The revascularization procedure using suction thrombectomy under proximal protection was considered effective against the acute cervical carotid occlusions, in particular, those proximal to the ophthalmic artery branch.

Clot Removal Therapy by Aspiration and Extraction for Acute Embolic Carotid Occlusion

s of Oral Proceedings: 2006 Joint Annual Meeting of the AANS/CNS Cerebrovascular Section and the American Society of Interventional & Therapeutic Neuroradiology Caribe Royale Orlando—Orlando, Florida February 17–20, 2006: Anatomy: Cerebrovascular

Clot Removal Therapy by Aspiration and Extraction for Acute Embolic Carotid Occlusion

BACKGROUND AND PURPOSE: The purpose of our retrospective study was to investigate the feasibility, safety, and efficacy of clot removal therapy by aspiration and extraction for patients with acute stroke with embolic internal carotid artery (ICA) occlusion. METHODS: Of 814 consecutive patients with acute ischemic stroke admitted to our institution from March 2003 to April 2005, clot removal therapy was performed for 14. Inclusion criteria were patients (1) presenting within 6 hours of onset of cardioembolic stroke, (2) with serious neurologic symptoms defined by a National Institutes of Health Stroke Scale (NIHSS) score of at least 11, (3) without extensive high signal intensity on diffusion-weighted MR images but with decreased ipsilateral hemispheric cerebral blood flow on perfusion-weighted images (perfusion/diffusion mismatch), and (4) with total ICA occlusion on angiograms. We removed clots by aspiration and extraction with a microsnare through either a guiding or balloon guide catheter. Radiographic results, 7-day NIHSS, 3-month modified Rankin Scale, and procedure-related complications were evaluated. RESULTS: Of 10 patients treated with the balloon guide catheter to temporarily interrupt proximal flow, 7 obtained complete or partial recanalization. The 4 patients treated with the guiding catheter had no recanalization. Of the 7 patients with recanalization, 6 had favorable 7-day neurologic and 3-month functional outcome; all showed anatomic crossflow via the anterior communicating artery. A procedure-related complication, distal embolization into the ipsilateral anterior cerebral artery, occurred in 1 patient. CONCLUSION: Balloon guide catheter-assisted clot removal therapy for embolic ICA occlusion may provide a high recanalization rate and good clinical outcome in patients with anatomic crossflow.

Endovascular Treatment of Urgent Carotid Occlusion

Emergency revascularization of acute carotid artery occlusion is still controversial.We treated 15 patients (13 men and two women, mean age of 67.3 years) with acute atherosclerotic carotid occlusion by endovascular procedures and evaluated the usefulness of this treatment. All of the patients were evaluated with emergency MRI and MRA before treatment. Intracranial tandem arterial occlusion due to distal embolism was observed in nine patients, and contralateral carotid stenosis (> 70%) was observed in seven. The mean NIHSS score of the patients was 15.4 +/- 7.4 (mean +/- SD) before treatment. Treatment modality included local intraarterial fibrinolysis (LIF), percutaneous transluminal angioplasty (PTA), and carotid artery stenting (CAS). A protective balloon was successfully placed in the distal carotid artery through the plaque before recanalization in seven patients. Three patients were treated with LIF+PTA, five with PTA+CAS, six with LIF+PTA+CAS, and one with PTA only. Successful recanalization of the carotid artery was obtained in 14 of the 15 patients, and distal tandem middle cerebral artery occlusion was also successfully recanalized in eight of the nine patients. GOS was four or five in eight patients (good outcome group) and 1-3 in seven patients (poor outcome group). Mean NIHSS score of the 15 patients was (6.9 +/- 7.4) after treatment. Preoperative NIHSS score (10.3 +/- 7.4) in the good outcome group was significantly lower than that (21.3 +/- 5.4) in the poor outcome group. The protective balloon technique, PTA with stenting, seems to be useful for acute revascularization of urgent carotid occlusion. Simultaneous treatment of the intracranial tandem occlusive lesion is essential to achieve good clini-cal results. Patients with acute carotid occlusion with NIHSS scores of less than 16 could be good candidates for this advanced treatment.

Surgical management of acute carotid thrombosis after carotid stenting: A report of three cases

We report three cases of symptomatic acute carotid thrombosis occurring after carotid artery stenting (CAS). CASE 1: A patient presented with crescendo transient ischemic attacks on the second day after CAS. Ultrasound images demonstrated incomplete in-stent thrombosis due to plaque protrusion. The urgent surgical procedure consisted of stent removal and carotid thromboendarterectomy. CASE 2: A case of complete thrombosis of a carotid stent occurred 4 days after implantation in a patient with essential thrombocythemia diagnosed by chance. The surgical strategy included stent removal and carotid thromboendarterectomy. CASE 3: Cardiac multiple embolisms in a patient with chronic atrial fibrillation caused concomitant leg ischemia and acute carotid stent occlusion 2 hours after CAS. Cerebral reperfusion was established by embolectomy, without removing the stent. At the same time, the right leg ischemia was resolved by a thromboembolectomy with a Fogarty catheter. These three cases demonstrate that acute thrombosis after carotid stenting can be managed successfully with emergent surgical intervention. Thromboendarterectomy with stent removal or in selected cases, simple thromboembolectomy, can minimize neurologic sequelae in patients suffering from acute post-stenting carotid thrombosis.

Management strategy for carotid artery steno-occlusion

Recently the role of surgical and interventional therapy has been increasing in the management of ischemic stroke due to carotid artery stenosis or occlusion. Various treatment modalities have been reported to be beneficial if these procedures are performed within therapeutic window and with optimal indication: intravascular thrombolysis for acute carotid occlusion, extracranial–intracranial (EC–IC) bypass surgery for hemodynamic ischemic stroke, and carotid endarterectomy (CEA) or percutaneous transluminal angioplasty and stenting (PTAS) for severe symptomatic carotid artery stenosis or occlusion. Recent management strategies will be described from literature review and our limited experience for enhancing the effectiveness of treatment modalities for carotid artery stenosis or occlusion.

Response to intra-arterial and combined intravenous and intra-arterial thrombolytic therapy in patients with distal internal carotid artery occlusion.

The objective of this study was to determine the clinical features, angiographic findings, and response to treatment with thrombolytic therapy in patients with ischemic stroke caused by acute occlusion of the distal internal carotid artery. This is a retrospective case series from a prospectively collected stroke database for patients with acute internal carotid occlusion presenting within 6 hours of stroke onset to evaluate safety, feasibility, and response to thrombolytic therapy. The University Hospital-based brain attack database was reviewed over a 5-year period. Demographics, clinical features, stroke mechanisms, severity, imaging findings, type of thrombolysis, treatment responses, mortality, and long-term outcome using modified Rankin Scale and Barthel Index were determined. The short-term outcome was assessed using the National Institutes of Health Stroke Scale (NIHSS). Acute thrombolytic therapy was administered using recombinant tissue plasminogen activator or urokinase given intra-arterially or in combination with intravenous (IV) routes. Two hundred seven patients treated with thrombolysis between 1995 and 2000 were reviewed, and of these, 101 were studied with cerebral angiography. Eighteen patients were identified with acute ischemic stroke and ipsilateral occlusion of the distal internal carotid artery. Time to treatment was the most powerful predictor of response to thrombolytic therapy (P<0.001). The response to therapy also correlated well with the severity of the initial clinical deficit as judged by the NIHSS (P<0.001). There was no difference in recanalization rate, symptomatic hemorrhage, and NIHSS for IV/intra-arterial (IA) versus IA alone (P=NS). Complete angiographic recanalization was accomplished in 80% of those who received combined IV/IA thrombolysis and in 62% of those who received IA therapy (P=NS). Those with distal occlusions extending to the middle and anterior cerebral arteries were the least likely to respond to thrombolysis. Symptomatic intracerebral hemorrhage occurred in 20% of the patients receiving IV/IA therapy, and in 15% of the IA only (P=NS). At 24 hours, the NIHSS dropped by 3 points in the IA group and 4 points in the IV/IA group (P=NS). Mild disability with independence was found in 77% of the survivors at 3-month follow-up. The mortality rate was 50% in this group despite thrombolysis. Thrombolytic therapy using a combination of IV and IA routes and using the IA-only route may be effective in improving outcome for the patients suffering from occlusion of the distal internal carotid artery. Shorter intervals between onset and treatment seem to be correlated with higher rate of recanalization and improved outcome.

Combined therapeutic approach of intra-arterial thrombolysis and carotid endarterectomy in selected patients with acute thrombotic carotid occlusion

Purpose: The feasibility and clinical outcome of intra-arterial thrombolysis followed by carotid endarterectomy (CEA) for acute thrombotic occlusion of the internal carotid artery (ICA) were evaluated. Methods: Intra-arterial thrombolysis and CEA were performed in four patients with acute thrombotic ICA occlusion. Computed tomography scans, cerebral angiograms, and the severity of carotid plaques were examined, and the patients' clinical outcome was evaluated. Results: All 4 patients had severe hemiparesis; 3 patients were alert, and 1 patient was lethargic at the time of hospital admission. New lesions were not shown by means of the initial computed tomography scan. ICA occlusion was indicated in all four patients by means of cerebral angiograms; in three patients, middle cerebral artery occlusion was noted. Collateral circulation was manifested in all patients. Partial recanalization of the occluded ICA was obtained in all patients. Two patients with severe residual ICA stenosis underwent an emergency CEA soon after thrombolysis; the other two patients were treated by means of CEA in the subacute or chromic stage. Plaque rupture and intraplaque hemorrhage were seen in all four patients. All four patients recovered completely, and restenosis of the ICA was not shown by means of follow-up angiograms. Conclusion: Intra-arterial thrombolysis followed by CEA may be an effective therapeutic approach for treating acute thrombotic ICA occlusion. The optimal timing of CEA remains controversial. (J Vasc Surg 2001;34:532-40.)

Laser Doppler imaging of changes in cerebral blood flow during acute carotid occlusion.

To determine by laser Doppler imaging (LDI) the spatial and temporal characteristics of the changes in cerebral blood flow (CBF) in response to electrical forepaw stimulation in rats before and during acute unilateral carotid occlusion. Single laser Doppler (LD) probes provide a minimally invasive approach for measuring CBF changes due to functional stimulation. Using an electrical forepaw stimulation model in rats, we have previously demonstrated a prolongation in the temporal dynamics of the CBF response during acute mechanical carotid occlusion. However, the spatial resolution of this model system was limited by the diameter of the single LD probe. Recently, we have successfully used LDI, which uses an optically driven low power laser beam to measure CBF changes in two dimensions, to investigate the spatial and temporal changes in CBF due to forepaw stimulation. LDI was used to measure the spatial and temporal characteristics of the changes in CBF response in a-chloralose anesthetized rats (n = 5) both before and during acute unilateral occlusion of the common carotid contralateral to the forepaw stimulated. Acute mechanical occlusion of the common carotid contralateral to the forepaw stimulated did not affect the area of activation due to functional stimulation. However, the amplitude of the CBF response was significantly reduced compared to prior to occlusion. Further, acute occlusion led to a significant prolongation of temporal dynamics of the CBF response. These observations are in agreement with previous results we have obtained using a single LD probe. Our results suggest a promising role for the application of LDI to study the spatial and temporal characteristics of CBF changes in animal models and may allow a diagnostic technique for testing patients with carotid occlusion.

Acute carotid occlusion alters the activation flow coupling response to forepaw stimulation in a rat model.

To determine whether the hemodynamic response to functional stimulation is sensitive to proximal arterial occlusion, we measured the activation flow coupling response in a rat model of acute reversible vascular occlusion. In alpha-chloralose-anesthetized rats (n=18), laser Doppler measurements were made through a thinned skull over the somatosensory cortex in response to electrical forepaw stimulation. Signal-averaged responses to 4 and 8 seconds of electrical forepaw stimulation were obtained before, during, and shortly after acute unilateral or bilateral carotid occlusion produced with the use of a surgically placed snare. Baseline cerebral blood flow was significantly decreased over the forepaw region of the somatosensory cortex after both occlusion of the carotid contralateral to the stimulated forepaw and bilateral occlusion compared with preocclusion (P<0.05). Postocclusion and ipsilateral occlusion led to a nonsignificant increase in baseline cerebral blood flow compared with preocclusion. Contralateral carotid occlusion and bilateral occlusion significantly prolonged the temporal characteristics of the flow response, especially the delay to peak (P<0.05), compared with preocclusion, whereas ipsilateral carotid occlusion significantly shortened the delay to peak (P<0.05). Only contralateral carotid occlusion produced a significant reduction in the peak amplitude of the flow response compared with preocclusion (P<0.05). These findings suggest that temporal characteristics of functional activation responses are sensitive to alterations in the proximal arterial supply and, conversely, that functional activation studies must be interpreted with consideration of proximal arterial disease.

Predicting the effect of carotid artery occlusion during carotid endarterectomy: comparing transcranial doppler measurements and cerebral angiography.

We correlated the mean transcranial Doppler blood flow velocity (FVm) during carotid endarterectomy with the functional collateral pathway(s) documented by angiography. Three patient groups were established: group 1 was dependent on the anterior communicating artery, group 2 on the anterior communicating artery and ipsilateral posterior communicating artery, and group 3 on the ipsilateral posterior communicating artery. Continuous middle cerebral artery FVm and electroencephalographic monitoring were performed in 45 patients during carotid endarterectomy. Clamped FVm was lowest in group 3 at 17+/-9 cm/s versus 36+/-16 and 33+/-11 cm/s for groups 1 and 2 (P<0.01). FVm values in groups 1 and 2 were similar. There was significant cerebral arterial vasodilation in group 3 patients on the basis of a pulsatility index of 0.38+/-0.15. The maximum FVm after clamp release was similar among the 3 groups. Normalized blood flow velocity 1 minute before release of the clamp was increased from the minimum flow velocity after clamping only in group 1 and 2 patients. The ipsilateral posterior communicating artery is a minor collateral pathway during acute carotid occlusion that contributes little to the collateral flow if there is a functional anterior communicating artery. Collateral flow through the middle cerebral artery is not recruited during occlusion in group 3 patients. The reperfusion FVm transient is independent of the primary collateral pathway. Documentation of functional collateral pathways on the basis of Doppler or angiographic examination may be advantageous in future studies since it can provide the basis for comparison among studies.

Thrombolytic therapy by pro-Urokinase combined with tissue plasminogen activator in an acute internal carotid occlusion

Acute occlusion of the internal carotid artery by a cardiac embolus was quickly recanalized by the new thrombolytic agent, pro-Urokinase, combined with tissue plasminogen activator, without any side-effects. This is the first reported case of thrombolytic therapy of a cerebral artery using these agents in combination.

Carotid surgery: the past is prologue. The John Homans lecture.

Carotid surgery: the past is prologue. The John Homans lecture.

Intracranial intraarterial thrombolysis facilitated by microcatheter navigation through an occluded cervical internal carotid artery

This report covers a series of four patients with acute cervical carotid occlusion and profound neurological deficits who were treated with intracranial intraarterial thrombolysis. All of the patients presented with arm plegia with variable leg involvement and two of them had global aphasia. Angiography identified occlusion of the proximal internal carotid artery (ICA) in each case and intracranial thromboembolus of the supraclinoid ICA and/or its branches. Catheter navigation through the occluded ICA segment was straightforward in three patients and somewhat difficult in one patient with an 80% ICA stenosis. Intraarterial urokinase infusion along with mechanical clot disruption was performed at the clot site in the middle cerebral artery, supraclinoid ICA, and/or anterior cerebral artery. All patients had recanalization of the treated artery after urokinase infusion. Antegrade flow through the ICA was reestablished in two patients, and good collateral filling across the anterior communicating artery was established in the other two. All patients had major pretreatment deficits (mean National Institutes of Health (NIH) Stroke Score 24 +/-4) with significant improvement noted at 3 months posttreatment (NIH Stroke Score 7 +/-6;p=0.03). Two patients made a dramatic early recovery. Postprocedure computerized tomography revealed no abnormality in one and asymptomatic basal ganglia high density from repeated local contrast injections in two patients. On the basis of their findings in this small study group the authors suggest that catheter navigation through a presumably occluded carotid artery is feasible and possibly effective in thrombolytic therapy of intracranial thrombolysis. Further study with clinical trials is necessary to determine the safety and efficacy of this technique.

Endovascular Treatment of Urgent Carotid Occlusion

Emergency revascularization of acute carotid artery occlusion is still controversial. We treated 15 patients (13 men and two women, mean age of 67.3 years) with acute atherosclerotic carotid occlusion by endovascular procedures and evaluated the usefulness of this treatment. All of the patients were evaluated with emergency MRI and MRA before treatment. Intracranial tandem arterial occlusion due to distal embolism was observed in nine patients, and contralateral carotid stenosis (&gt;70%) was observed in seven. The mean NIHSS score of the patients was 15.4±7.4 (mean±SD) before treatment. Treatment modality included local intraarterial fibrinolysis (LIF), percutaneous transluminal angioplasty (PTA), and carotid artery stenting (CAS). A protective balloon was successfully placed in the distal carotid artery through the plaque before recanalization in seven patients. Three patients were treated with LIF+PTA, five with PTA+CAS, six with LIF+PTA+CAS, and one with PTA only. Successful recanalization of the carotid artery was obtained in 14 of the 15 patients, and distal tandem middle cerebral artery occlusion was also successfully recanalized in eight of the nine patients. GOS was four or five in eight patients (good outcome group) and 1–3 in seven patients (poor outcome group). Mean NIHSS score of the 15 patients was (6.9 ± 7.4) after treatment. Preoperative NIHSS score (10.3 ± 7.4) in the good outcome group was significantly lower than that (21.3 ± 5.4) in the poor outcome group. The protective balloon technique, PTA with stenting, seems to be useful for acute revascularization of urgent carotid occlusion. Simultaneous treatment of the intracranial tandem occlusive lesion is essential to achieve good clini-cal results. Patients with acute carotid occlusion with NIHSS scores of less than 16 could be good candidates for this advanced treatment.

Carotid endarterectomy and local intraarterial thrombolysis: Simultaneous procedure in acute occlusion of the internal carotid artery and middle cerebral artery embolism

Patients with severe neurologic deficits caused by acute occlusion of the internal carotid artery represent a prognostically unfavorable group with a persistent neurologic deficit of 40% to 69% and a mortality rate of 16% to 55%.1Meyer FB Sundt Jr, TM Piepgras DG Sandok BA Forbes G. Emergency carotid endarterectomy for patients with acute carotid occlusion and profound neurological deficits.Ann Surg. 1986; 203: 82-89Crossref PubMed Scopus (199) Google Scholar We report a case of a 66-year-old man with symptomatic stenosis of the left internal carotid artery (> 90%). Two weeks before he was admitted, he had two left hemispheric transient ischemic attacks with right arm and facial weakness. At the first neurologic examination a 90% stenosis of the internal carotid artery was diagnosed by Doppler study and magnetic resonance angiography. The computed tomography scan of the brain revealed small lacunar infarctions but no fresh cortical ischemia. Carotid endarterectomy of the symptomatic carotid artery stenosis was recommended, but the patient refused any treatment until a third episode of brachiofacial weakness occurred. After he was admitted to the Department of Vascular Surgery, the patient had a severe left hemispheric stroke even though he was given therapeutic levels of heparin (25,000 IU intravenously daily), with complete hemiplegia of the right side, global aphasia, and progressing lack of consciousness. Acute carotid artery occlusion was diagnosed (Doppler study, loss of bruit), and emergency operation by carotid endarterectomy was performed. Intraoperative needle-angiography after eversion endarterectomy revealed partial occlusion of the middle cerebral artery ( Fig. 1 ). We performed additional intraoperative lysis-therapy via the reconstructed internal carotid artery (500,000 IU urokinase). Three hours after operation the patient's hemiplegia and aphasia diminished step-by-step, and after 24 hours the patient recovered almost completely from his neurologic deficits. A selective carotid angiogram obtained 3 days later showed evidence of a normal intracerebral vascular architecture with no residual thromboembolism ( Fig. 2 ). Fig. 2Selective angiography of left carotid artery 3 days after eversion endarterectomy: extracranial part of internal carotid artery (A), intracerebral internal carotid artery with patent middle cerebral artery (B,C).View Large Image Figure ViewerDownload (PPT)Fig. 2Selective angiography of left carotid artery 3 days after eversion endarterectomy: extracranial part of internal carotid artery (A), intracerebral internal carotid artery with patent middle cerebral artery (B,C).View Large Image Figure ViewerDownload (PPT)Fig. 2Selective angiography of left carotid artery 3 days after eversion endarterectomy: extracranial part of internal carotid artery (A), intracerebral internal carotid artery with patent middle cerebral artery (B,C).View Large Image Figure ViewerDownload (PPT)At discharge from the hospital, the patient was free of complaint. A last neurologic examination indicated only a slight weakness of a facial branch and signs of dysdiadochokinesia of the right arm. Although several series of emergency carotid endarterectomies with sometimes dramatic recovery have been presented, acute stroke is generally considered as a contraindication to carotid endarterectomy, with rare exceptions in individual cases.2Gertler JP Blankensteijn JD Brewster DC et al.Carotid endarterectomy for unstable and compelling neurologic conditions: Do results justify an aggressive approach.J VASC SURG. 1994; 19: 32-42Abstract Full Text Full Text PDF PubMed Scopus (52) Google Scholar, 3Moore WS Mohr JP Najafi H Robertson JT Stoney RJ Toole JF. Carotid endarterectomy: practice guidelines—report of the Ad Hoc Committee to the Joint Council of the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery.J VASC SURG. 1992; 15: 469-479Abstract Full Text Full Text PDF PubMed Scopus (125) Google Scholar The reasons for this include neurologic instability and fear of clinical deterioration by secondary hemorrhage in the infarcted area. It has been demonstrated that acute cerebrovascular arterial occlusion could be treated successfully by local intraarterial and systemic lysis-therapy.4Del Zoppo GJ Pessin MS Mori E Hacke W. Thrombolytic interventions in acute thrombotic and embolic stroke.Semin Neurol. 1991; 11: 368-384Crossref PubMed Scopus (85) Google Scholar, 5Higashida RT Van Halbach V Barnwell SL Dowd CF Hieshima GB. Thrombolytic therapy in acute stroke.J Endovasc Surg. 1994; 1: 4-15Crossref PubMed Scopus (35) Google Scholar Failure of lysis-therapy of an acute carotid artery occlusion can occur in patients with a preexisting high-grade stenosis. Also thrombolysis is not able to treat atherosclerotic carotid artery stenosis sufficiently from a surgical point of view because a high-grade carotid artery stenosis remains, causing the risk of ongoing embolism. Therefore simultaneous carotid endarterectomy and intraoperative lysis-therapy may be a therapeutic alternative in the treatment of acute ischemic stroke by carotid artery occlusion and middle cerebral artery thromboembolism. This is the first case of a simultaneous emergency carotid endarterectomy and intraoperative thrombolysis in the treatment of acute carotid artery occlusion and middle cerebral artery embolism in the literature. This procedure should be taken into consideration in the treatment of acute stroke in patients with a preexisting high-grade carotid artery stenosis.

Correlation of experimental rCBF determinations in goats with flow measurements from a Doppler-modified carotid artery shunt.

A carotid artery shunt system has been developed that continuously monitors blood flow rates by embedding a Doppler crystal in the shunt wall. The crystal ranges through a "liquid lens" that enables it to be placed without violation of the shunt lumen. Because the crystal is at a fixed angle (45 degrees) to the axis of blood flow and the diameter of the lumen remains constant, a linear relationship exists between flow rates and the Doppler velocity signal. This shunt system was previously tested in vitro using a pulsatile pump and was found to be accurate to within 4.7% of the actual flow rate. In the present study, animal (goat) experiments were performed consisting of simultaneous carotid shunt flow and bilateral rCBF measurements by the radiolabeled microsphere technique to determine in vivo the accuracy of this Doppler modified shunt and to ascertain the ability of shunt flow to increase in the face of acute contralateral carotid occlusion. Data from five animals show that in vivo shunt flow can be recorded to within 13% of control rCBF and that shunt flow increases nearly 50% under conditions of distal demand (contralateral carotid occlusion). This device may prove useful in laboratory studies of carotid shunt dynamics and in clinical practice to quickly detect correctable shunt flow abnormalities.

Cerebral hyperperfusion syndrome: A cause of neurologic dysfunction after carotid endarterectomy

Neurologic deficits evident when patients initially awaken from surgery are generally due to intraoperative embolization or inadequate cerebral protection in patients with marginal cerebral perfusion; neurologic deficits occurring in the immediate postoperative period are usually related to acute carotid occlusion or embolization. However, in a small subset of patients, transient postoperative neurologic dysfunction seems to be related to a syndrome of cerebral hyperperfusion rather than a lack of adequate cerebral blood flow. This study describes the courses of 10 patients with classic findings of cerebral hyperperfusion syndrome. Typically, this syndrome occurred in patients with longstanding severe chronic cerebral ischemia and occurred after correction of a very high-grade carotid stenosis. Intraoperatively, there was often a dramatic increase in xenon-labeled cerebral blood flows, with postocclusion flows sometimes attaining three to four times baseline levels. Postoperatively, the patients initially did well. However, over the next several days, many of them began to complain of unilateral headache on the operated side and subsequently had seizures. Electroencephalography obtained during this period uniformly revealed periodic lateralizing epileptiform discharges on the side of the brain ipsilateral to the endarterectomy. Although neurologic dysfunction fully resolved in all of the patients in this group, it is possible that intracerebral hemorrhage may occur in some patients with hyperperfusion syndrome. The pathophysiology of this syndrome is believed to be related to preoperative loss of cerebral autoregulatory mechanisms caused by chronic cerebral ischemia.