Intraluminal clot of the carotid artery detected radiographically

Intraluminal Thrombus of the Extracranial Cerebral Arteries in Acute Ischemic Stroke: Manifestations, Treatment Strategies, and Outcome

Background

Intraluminal thrombus (ILT) of the cervical arteries is an uncommon finding that can lead to acute or recurrent ischemic stroke. Currently, antithrombotic therapy in the form of antiplatelet and/or anticoagulation is considered the mainstay of treatment, but evidence of which one has a better outcome is lacking.

Methods

A retrospective cohort study included 28 patients diagnosed with acute stroke or transient ischemic attack with ILT of the extracranial arteries from 2013 to 2022. The primary efficacy outcome was assessed as recurrent stroke, and the primary safety outcome was assessed as hemorrhagic complications. Secondary outcomes were assessed as the resolution of thrombi by CT angiography (CTA) and clinical improvement by the Modified Rankin Scale (mRS) and NIH Stroke Scale (NIHSS).

Results

Out of 28 patients, more than half (57.1%; n = 16) were males with a mean age of 57.8 ± 9.5 years and an average BMI of 26.9 ± 4.5 kg/m2. As initial treatment, twenty-four patients received anticoagulation and four received antiplatelet agents. Recurrent strokes were found in four patients (14.29%), and all were initially treated with anticoagulation. One patient in the anticoagulation group had a significant retroperitoneal hemorrhage. None of the patients in the antiplatelets group had a recurrent stroke or bleeding event. Initial treatment with antiplatelet agents significantly improved the NIHSS on day 7 (P = 0.017). A significant improvement in NIHSS on day 90 was observed in the anticoagulant group (P = 0.011). In the follow-up CTA performed on 24 patients, 18 (75%) showed complete resolution (3 out of 3 (100%) in the antiplatelet group and 15 out of 21 (71.43%) in the anticoagulant group).

Conclusion

Initial treatment with anticoagulants improves neurologic outcomes in patients with ILT-induced acute ischemic stroke but carries the risk of recurrent stroke and bleeding. However, initial treatment with dual antiplatelet agents appears to have comparable efficacy without sequelae, particularly in atherosclerosis-induced ILT.

Natural history of carotid artery free-floating thrombus—A single center, consecutive cohort analysis

Introduction

Carotid free-floating thrombus (CFFT) is a rare cause of stroke and is thought to be associated with a high risk of recurrent cerebrovascular ischaemic events. The existing data on the natural history and optimal treatment modalities of CFFT is scanty and no clear recommendations exist.

Objective

A retrospective analysis, single-center cohort of consecutive patients diagnosed with CFFT was conducted, investigating the risk for recurrent cerebrovascular ischaemic events.

Methods

We performed a single-center retrospective analysis including all patients presenting at our tertiary center between January 2005 and December 2020 with symptoms consistent with ischaemic stroke and/or transient ischaemic attack. Digital subtraction angiography (DSA), computed tomography angiography (CTA) or magnetic resonance angiography (MRA) were used to diagnose CFFT. In all included patients, CFFT was confirmed with a second imaging modality. CFFT was defined on imaging as a defect in contrast filling extending into the carotid lumen. We gathered information on vascular risk factors, diagnosis and follow-up methods, modality of treatment and neurological outcome. A survival analysis was performed, assessing the risk for recurrent cerebrovascular events.

Results

In total, N = 62 patients presenting with symptomatic CFFT were included. Mean age was 68 years, 69% (43/62) of patients were male, 52% (32/62) current or previous smokers, 76% (47/62) suffered from arterial hypertension, 68% (42/62) from dyslipidaemia, and 31% (19/62) from diabetes mellitus. Overall, 71% (44/62) of patients received any kind of intervention [endovascular or surgical carotid thrombo-endartectomy (CEA)] at any time point during follow-up. Sixteen percent of patients (10/62) received intervention within 48 h after diagnosis of CFFT. The survival analysis and Kaplan-Meier model censoring patients at the time of intervention or last follow-up showed that the risk for any recurrent ischaemic stroke was 19.7% within the first 7 days and 27.4% within 3 months after diagnosis. No patients experienced a new ischaemic stroke beyond 11 days after diagnosis of CFTT (n = 17).

Conclusion

The risk of recurrent ischaemic events in patients with CFFT is high, especially in the first week after diagnosis. Prospective studies are needed to further investigate the optimal management of these patients.

Intracranial non-occlusive intraluminal thrombus may indicate underlying etiology of large vessel occlusion in patients undergoing endovascular therapy

BACKGROUND

The underlying etiology of intracranial non-occlusive intraluminal thrombus (iNOT) remains unknown. This study aimed to investigate whether the presence of iNOT can indicate the underlying etiology of large vessel occlusion (LVO) in patients undergoing endovascular therapy (EVT).

METHODS

Among patients who underwent EVT at three comprehensive stroke centers, we included those with intracranial LVO in the anterior circulation. The presence of iNOT was determined by pretreatment DSA. We investigated the association between iNOT and intracranial atherosclerotic stenosis (ICAS) related LVO.

RESULTS

Of 546 patients, 44 (8.1%) had iNOT. Patients with iNOT were younger, had less hypertension, atrial fibrillation, and a history of antiplatelet use. In addition, the involvement of the M1 segment of the middle cerebral artery (MCA) was more frequent. However, they had a lower National Institutes of Health Stroke Scale (NIHSS) score on admission and longer onset to recanalization time compared with patients with no iNOT. In a logistic regression model adjusting for age, sex, atrial fibrillation, smoking, prior antiplatelet and anticoagulant use, intravenous tissue plasminogen activator, NIHSS on admission, number of technical trials, intraprocedural re-occlusion, and the location of LVO (p<0.10 in the univariate analysis), the presence of iNOT was significantly associated with ICAS related LVO (adjusted OR 3.04; 95% CI 1.33 to 6.90; p=0.007).

CONCLUSIONS

The presence of iNOT may reflect an underlying ICAS related LVO in patients undergoing EVT.

Intraluminal Thrombi in the Cervico-Cephalic Arteries

Background and Purpose- Intraluminal thrombus (ILT) is an uncommon finding among patients with ischemic stroke. We report clinical-imaging manifestations, treatment offered, and outcome among patients with ischemic stroke/transient ischemic attack and ILT in their cervico-cephalic arteries. Methods- Sixty-one of 3750 consecutive patients with acute ischemic stroke/transient ischemic attack (within 24 hours of onset) and ILT on initial arch-to-vertex computed tomography angiography from April 2015 through September 2017 constituted the prospective study cohort. Functional outcome was assessed using the modified Rankin Scale score with functional independence at discharge defined as modified Rankin Scale score ≤2. Results- Prevalence of ILT on computed tomography angiography was 1.6% (95% CI, 1.2%-2.1%). Median age was 67 years (interquartile range, 56-73), and 40 subjects (65%) were male. The initial clinical presentation included transient ischemic attack in 12 (20%) and stroke in 49 patients (80%); most strokes (76%) were mild (National Institutes of Health Stroke Scale ≤5). The most common ILT location was cervical carotid or vertebral artery (n=48 [79%]) followed by intracranial (n=11 [18%]) and tandem lesions (n=2 [3%]). The most common initial treatment strategy was combination antithrombotics (heparin with single antiplatelet agent) among 57 patients (93%). Follow-up computed tomography angiography (n=59), after a median 6 days (interquartile range 4-10 days), revealed thrombus resolution in 44 patients (75% [completely in 27%]). Twenty four of 30 patients (80%) with >50% residual carotid stenosis underwent carotid revascularization (endarterectomy in 15 and stenting in 9 patients) without peri-procedural complications a median of 9 days after symptom onset. In-hospital stroke recurrence occurred in 4 patients (6.6%). Functional independence was achieved in 46 patients (75%) at discharge. Conclusions- Patients presenting with acute stroke/transient ischemic attack with ILT on baseline imaging have a favorable clinical course in hospital with low stroke recurrence, high rate of thrombus resolution, and good functional outcome when treated with combination antithrombotic therapy.

Diagnosis and management of carotid free-floating thrombus: A systematic literature review

Background

There is no consensus regarding the management of carotid free-floating thrombi in patients with acute ischemic stroke and transient ischemic attack.

Aims

This systematic review aims to (1) describe the current imaging methods for diagnosis of carotid free-floating thrombi and its associated risk factors, (2) estimate the proportion of carotid free-floating thrombi diagnosed in stroke patients, (3) estimate the proportion of carotid free-floating thrombi patients treated medically and surgically, and (4) evaluate 30-day outcomes.

Methods

We searched MEDLINE, EMBASE, and manually for references reporting carotid free-floating thrombi from 1960 until June 2017. We estimated the frequency of carotid free-floating thrombi and evaluated 30-day outcomes using Cox regression. We defined the timing of surgical intervention as early (less than 72 h) and delayed (more or equal to 72 h).

Summary of review

We retrieved 525 carotid free-floating thrombi cases from 58 case series and 83 case reports. Carotid free-floating thrombi were present in 1.53% of stroke patients. Carotid free-floating thrombi diagnosis was made by digital subtraction angiography (38.1%), carotid duplex ultrasound (29.5%), and computed tomography angiography (29.5%). The 30-day risk of transient ischemic attack, silent brain ischemia, any stroke or death was 17.1%. In multivariate analyses, there were no differences in outcome for any anticoagulation regime or timing of revascularization procedure.

Conclusions

The diagnosis of carotid free-floating thrombi is more common due to the increased use of early noninvasive vascular imaging in transient ischemic attack and stroke. It poses a high short-term risk of stroke and death, but there is as yet no established treatment. The low quality of evidence in the carotid free-floating thrombi literature limits the interpretation of our results and warrants a large-scale prospective cohort study in carotid free-floating thrombi.

Plateletpheresis: Nonoperative Management of Symptomatic Carotid Thrombosis in a Patient with Reactive Thrombocytosis

BACKGROUND

The most common pathology associated with an intraluminal carotid thrombus is underlying atherosclerosis. In rare cases, it may be associated with thrombocytosis. Currently there are no clear recommendations for the treatment of ischemic stroke associated with thrombocytosis. Our present case illustrates the use of plateletpheresis for the acute management of thrombocytosis complicated by an internal carotid artery thrombus resulting in a right middle cerebral artery stroke.

CASE DESCRIPTION

A 55-year-old female who presented with symptoms of acute, transient left hemiparesis and a National Institutes of Health Stroke Scale (NIHSS) score of 1. Initial head computed tomography (CT) scan was nonrevealing. Laboratory results revealed a mild hypochromic anemia and a platelet count of 1014 × 10³/mL. The patient was not a candidate for thrombolytic therapy due to the time window. Soon after admission, she experienced acute worsening of symptoms, with an NIHSS score of 18. CT angiography of the head and neck showed acute ischemic infarction involving the right middle cerebral artery territory with a nonocclusive intraluminal thrombus within the right carotid bulb. Aspirin 325 mg and intravenous heparin infusion were initiated. After a thorough workup, reactive thrombocytosis secondary to iron deficiency anemia was diagnosed. Plateletpheresis was started, and after 1 cycle the platelet count stabilized at 400 × 10³/mL. Complete thrombus resolution was confirmed on follow-up CT angiography on day 10 after admission without the need for surgical revascularization.

CONCLUSIONS

The role for plateletpheresis in treating secondary thrombocytosis is not well established. In cases with extreme thrombocytosis, immediate surgical thrombectomy may be contraindicated owing to a high risk of rethrombosis. Urgent cytoreduction with correction of the putative mechanism for thrombocytosis should be undertaken to provide optimal management.

Resolution of Occlusive Carotid Artery Thrombus Treated with Anticoagulation as Demonstrated on Duplex Ultrasonography

BACKGROUND AND PURPOSE

While the majority of cerebral ischemic events due to carotid occlusive disease result from atherosclerotic plaque rupture, intraluminal carotid artery thrombus occasionally occurs in patients without preexisting carotid atherosclerosis. Identification of nonatherosclerotic thrombus as the cause of the carotid occlusive disease can obviate the need for an interventional procedure, and resolution of thrombus can be monitored with B-mode duplex ultrasonography.

METHODS

We reviewed 3 patients treated on The Mount Sinai Hospital Stroke Unit with anticoagulation for nonatherosclerotic carotid thrombi and followed with serial Doppler ultrasonogrpahy for resolution of thrombus.

RESULTS

Occlusive carotid thrombus was successfully treated in all 3 patients with systemic anticoagulation. B-mode duplex ultrasonography allowed for demonstration of resolving thrombus.

CONCLUSION

Differentiation between a stenotic plaque and occlusive thrombus can be achieved by ultrasonographic analysis of thrombus morphology, attachment site potential, and characteristics of a resolving thrombus. Systemic anticoagulation can safely and effectively eliminate the risk for future embolization and complete occlusion of the carotid artery in patients who present with transient ischemic events or completed infarcts of small size.

Cancer-related Stroke due to Mural Thrombus in the Extracranial Carotid Artery

A 41-year-old man was admitted to our hospital because of a cancer-related stroke (CRS) caused by a thrombus of the extracranial carotid artery. He had undergone neoadjuvant radiochemotherapy for metastatic colorectal adenocarcinoma. The serum D-dimer values were within the normal range. We treated him with intravenous unfractionated heparin followed by warfarin. There were no recurrent stroke events over six months. The leading cause of a CRS is an embolism caused by hypercoagulopathy, mainly represented by non-bacterial thrombotic endocarditis. However, it was unusual that, in the current case, a thrombus of the extracranial carotid artery was formed with no significant residual stenosis, thus resulting in an artery-to-artery embolism.

Free-floating thrombus in stroke patients with nonstenotic internal carotid artery-an ultrasonographic study

BACKGROUND

There are multiple causes of free-floating thrombus (FFT) formation in carotid arteries. The purpose of this study was to evaluate the incidence and natural history of FFT in nonstenotic internal carotid arteries of patients with acute ischemic stroke.

METHODS

During a 50-month period, 3,200 consecutive patients with acute ischemic stroke were evaluated for internal carotid artery stenosis and the presence of FFT by color-coded duplex ultrasonography. Diagnostic workup included brain CT, transthoracic echocardiography, Holter electrocardiogram, and hypercoagulability state evaluation.

RESULTS

We found an FFT in 5 (0.18%) of 2,757 patients with acute stroke and nonstenotic internal carotid artery (mean age 44 years). The underlying pathology was hypercoagulable state in active pulmonary tuberculosis (n = 1), essential thrombocythemia (n = 1), thrombotic complications of nonstenotic plaques (n = 1), unknown (n = 2). All patients clinically improved under antiplatelet therapy. Follow-up color-coded duplex ultrasonography showed complete dissolution of FFT in all cases. There was no stroke recurrence.

CONCLUSIONS

Internal carotid artery FFT could be found in young stroke patients without identifiable arterial disease and could be resolved with antithrombotic treatment.

Iron-Deficiency Anemia Leading to Transient Ischemic Attacks due to Intraluminal Carotid Artery Thrombus

Reactive thrombocytosis secondary to iron-deficiency anemia (IDA) is a rare but recognized cause of stroke. We report the case of a patient with iron-deficiency anemia presenting with multiple transient ischemic attacks (TIA) due to intraluminal thrombus of an internal carotid artery. The putative mechanisms underlying anemia and stroke syndromes are not completely understood, and it is believed that iron deficiency may cause ischemic stroke by several potential mechanisms. Thrombocytosis is often associated with iron deficiency, and microcytosis produces a reduction in the red cell deformability and could produce a hypercoagulable state. The platelet count and function observed in iron-deficiency anemia could act synergistically to promote thrombus formation, especially in the setting of an underlying atherosclerotic disease. The presence of floating thrombus in a patient with clinical and MRI evidence of stroke represents a significant therapeutic dilemma and requires immediate decision about treatment.

Symptomatic patients with intraluminal carotid artery thrombus: outcome with a strategy of initial anticoagulation

OBJECT

The aim of this study was to define the optimal treatment for patients with symptomatic intraluminal carotid artery thrombus (ICAT).

METHODS

The authors performed a retrospective chart review of patients who had presented with symptomatic ICAT at their institution between 2001 and 2011.

RESULTS

Twenty-four patients (16 males and 8 females) with ICAT presented with ischemic stroke (18 patients) or transient ischemic attack ([TIA], 6 patients). All were initially treated using anticoagulation with or without antiplatelet drugs. Eight of these patients had no or only mild carotid artery stenosis on initial angiography and were treated with medical management alone. The remaining 16 patients had moderate or severe carotid stenosis on initial angiography; of these, 10 underwent delayed revascularization (8 patients, carotid endarterectomy [CEA]; 2 patients, angioplasty and stenting), 2 refused revascularization, and 4 were treated with medical therapy alone. One patient had multiple TIAs despite medical therapy and eventually underwent CEA; the remaining 23 patients had no TIAs after treatment. No patient suffered ischemic or hemorrhagic stroke while on anticoagulation therapy, either during the perioperative period or in the long-term follow-up; 1 patient died of an unrelated condition. The mean follow-up was 16.4 months.

CONCLUSIONS

Results of this study suggest that initial anticoagulation for symptomatic ICAT leads to a low rate of recurrent ischemic events and that carotid revascularization, if indicated, can be safely performed in a delayed manner.

Unusual positional compression of the internal carotid artery causes carotid thrombosis and cerebral ischemia

This article reports an unusual case of positional compression of internal carotid artery resulting in carotid thrombosis and stroke in a 37-year-old man. A patient was operated urgently for a free-floating thrombotic mass in the internal carotid artery. Open thrombectomy was performed in acute phase of stroke for prevention of the recapitulative cerebral thromboembolism. Hemiplegia completely disappeared within 7 months.

Floating thrombus as a marker of unstable atheromatous carotid plaque

Floating thrombus in a carotid artery is an uncommon pathology with a high risk of embolism. We present three patients diagnosed with acute stroke, with a floating thrombus complicating an atheromatous plaque, who were treated with anticoagulants and statins. Although two patients had satisfactory results, one patient suffered a stroke related to plaque progression nearly 3 years after initial presentation. Medical treatment seems to be a good initial option, although late cerebral ischemic complications may be seen due to carotid plaque instability. Delayed carotid endarterectomy or stenting should be considered in cases with subsequent plaque progression.

Intravenous thrombolytic treatment in a patient with transient ischemic attack associated with mural carotid thrombi

A 77-year old man experiencing frequent transient ischemic attacks for five days was admitted to our hospital. Radiological examinations including brain computed tomography, supraaortic computed tomography angiography were performed. Supraaortic computed tomography angiography revealed two thrombi in common carotid artery. Thrombi were located proximally, one of which was elongated and adhared to the arterial wall and the other one was located below bifurcation of left carotid artery. Since the case has been categorized as a high risk patient for ischemic stroke despite the normal neurological status, intravenous recombinant tissue plasminogen activator was given. Ischemic attacks completely ceased soon after thrombolysis. Control computed tomography angiography revealed normal findings with patent carotid artery, without any clot. To our knowledge this is the only case of transient ischemic attack treated with intravenous recombinant tissue plasminogen activator in the literature with the score of 0 on the National Institutes of Health Stroke Scale.

Distal migration of a floating carotid thrombus in a patient using oral contraceptives: a case report

Introduction

We report the case of a patient with distal migration of a floating carotid thrombus caused by oral contraceptives.

Case presentation

A 48-year-old woman using oral contraceptives suffered from dysarthria and gait disturbance. Examinations, including ultrasound and cerebral arteriogram, revealed a floating thrombus at the left carotid bifurcation with no stenosis. Despite antithrombotic therapy, the floating carotid thrombus migrated to the ipsilateral middle cerebral artery, resulting in a severe stroke.

Conclusion

Some floating thrombi are resistant to conservative therapy and have a risk of distal migration, which may cause a major stroke in the acute stage.

"Internal cross-clamping" for symptomatic internal carotid artery thrombus. Report of two cases

Both carotid endarterectomy and carotid artery stent placement with filter embolic protection present a higher risk for patients with internal carotid artery (ICA) lesions containing intraluminal thrombus. Despite the risk associated with intervention, patients with symptomatic intraluminal thrombus who were enrolled in the North American Symptomatic Endarterectomy Trial did better with surgical than medical treatment. We describe the novel use of an endovascular "internal cross-clamping" technique in two patients with symptomatic intraluminal thrombus in the ICA. A 57-year-old woman presented with a history of multiple episodes of left upper-extremity numbness, mild dysarthria, and agraphia occurring over the previous 24 hours. Cranial magnetic resonance imaging revealed a scattered watershed infarction of the right hemisphere and a critical stenosis of the right ICA. An 81-year-old man awoke with hemiplegia and inability to follow commands after undergoing a complicated carotid endarterectomy. Computed tomographic perfusion imaging demonstrated an increased time to peak in the left middle cerebral territory, and emergent angiography demonstrated both intimal flaps and thrombus in the endarterectomy bed. The lesions in both patients were treated with endovascular stent placement using both proximal and distal flow occlusion--a functional "internal cross-clamping"--for embolic protection. To our knowledge, this is the first report of internal trapping and stent placement for symptomatic carotid stenosis containing intraluminal thrombus. This treatment strategy should be added to the armamentarium of endovascular surgeons in selected patients with symptomatic carotid intraluminal thrombus.

Free-floating thrombus of the carotid artery: Literature review and case reports

BACKGROUND

Free-floating thrombus (FFT) of the carotid artery is an uncommon entity that usually presents as an acute emergency. Management is based on case reports and series because the natural history and optimal treatment are unknown. This study was conducted to systematically review the world literature in an attempt to better understand FFT, its presentation, distribution, management, and outcome.

METHOD

A literature search in all languages was performed of the PubMed database (> or =1950s) and Medline database (1966-November 2004). All relevant articles were reviewed and their references analyzed in a similar manner for further literature. Cases from the authors' institutions were reviewed as well. All cases within the reports were individually assessed for inclusion or exclusion. Inclusion required that the FFT originate or anchor within the carotid artery (ie, excluding emboli, arch thrombi with extensions into the carotid artery), be partially occluding (ie, excluding occlusions, "string-sign," microscopic thrombus), and ideally have an elongated or protrusive morphology, circumferential flow around the distal portion, and cyclical motion with the cardiac cycles.

RESULTS

There were 61 reports reviewed, of which 43 contained FFT cases. These reports had 342 cases (including the current series) that were reviewed, of which 145 met our inclusion criteria. A database was created for qualitative and quantitative assessment of all cases. When data were pooled, appropriate statistical analysis was performed. A limitation of the study is that FFT is under-reported and ill defined, which limited the analysis in quantity and quality. In addition, reporting is not uniform, and therefore, significant data were not always present. In attempting to define FFT and include or exclude cases, subjectivity is inherent.

CONCLUSIONS

FFT is more frequently reported in men than women, with a ratio of nearly 2:1 (P < .0001), and at a younger age than in most patients with carotid disease (P < .0001 when compared with North American Symptomatic Carotid Endarterectomy Trial, European Carotid Surgery Trial, and Asymptomatic Carotid Surgery Trial). Symptoms are present in 92% of patients. There was a trend for patients with FFT to be hypercoagulable (47% of those serologically tested). The internal carotid artery was the most commonly affected (75%), with atherosclerosis being the most common associated pathology. Medical and surgical management have both been used, with neither clearly superior to the other. Medical management for stabilizing neurologic deficits has less risk and less benefit than surgical intervention.

Thrombus endoluminal de l’artère carotide sans lésion sous-jacente

Strokes are rarely secondary to spontaneous carotid artery thrombosis. The objectives of this retrospective analysis were to define characteristic features and the clinical course. The study population included eight patients (6 females/2 males) seen at six university neurological centers. Age of onset was 46.5 years (range 38-52). Half of the patients had no vascular risk factor. Symptoms were TIA (n=1), strokes (n=7). Echotomography revealed intraluminal thrombus, with occlusion in 2 cases. Thrombi were found in common carotid artery (n=3), carotid bifurcation (n=2) and internal carotid artery (n=3). The thrombus was mobile in 4 cases. Seven patients were treated by anticoagulation therapy, one by surgery because of recurrent TIA. Further echotomographic exams revealed total resolution (3 cases) or decrease of the thrombus (3 cases). Occlusion was definitive in one patient. A cause was identified in six patients: acute leukemia (n=1), thrombocytopenic purpura (n=1), iron deficiency anemia (n=4).

Idiopathic free-floating thrombus of the common carotid artery

BACKGROUND

The observation of an intraluminal common carotid artery thrombus overlying a wall defect at ultrasonography or angiography is unusual. To our knowledge, there are no previous reports of a free-floating thrombus in the common carotid artery.

CASE REPORT

A 45-year-old woman who was previously healthy and on no medications presented with acute hemiparesis and aphasia. Following testing that included carotid duplex and transcranial Doppler ultrasonography, diffusion-weighted magnetic resonance imaging, and digital subtraction angiography, the patient underwent emergency open embolectomy. No underlying wall defect was seen at the time of imaging or surgery. No obvious hypercoagulable state could be identified. Her NIH Stroke Scale score improved from 26 at admission to 2 at three months and 1 at one year.

CONCLUSIONS

Multimodal imaging may have improved diagnosis and management in this patient with a unique finding. The source of the thrombus remains obscure.

Reconstructive surgery of the extracranial arteries

The first carotid endarterectomy (CEA) is usually accredited to Eastcott who reported in 1954 the successful incision of a diseased carotid bulb with end-to-end anastomosis of the internal carotid artery (ICA) to the common carotid artery (CCA). During the following years surgeons were quick to adopt and improve the intuitively attractive procedure. But by the early to mid 1980s several leading neurologists began to question the growing number of CEAs performed at that time. Six major CEA trials were then designed which are now completed or nearing completion. Most conclusive data are available from the North American Symptomatic Carotid Endarterectomy Trial (NASCET) for symptomatic carotid disease, and from the Asymptomatic Carotid Atherosclerosis Study (ACAS) for asymptomatic carotid disease. The key result of these studies is that CEA is beneficial to high grade symptomatic and asymptomatic carotid stenosis. While the benefit in symptomatic disease is clear, it may be negligible in asymptomatic patients suffering from other medical conditions, the most important being coronary artery disease. Since the conclusions from the different studies vary significantly, guidelines and recommendations with regard to CEA have been issued by a number of interest groups, so-called consensus conferences. The best known guidelines are published by the American Heart Association (AHA). However, the practice of interest groups to issue guidelines is currently being criticized, the main reason being that interest groups have different ideas and all claim the right to issue guidelines. At present we recommend CEA for symptomatic high-grade stenosis in patients without significant coincident disease. With regard to asymptomatic stenosis we suggest surgery to otherwise healthy patients if the stenosis is very narrow or progressive. Preoperative evaluation has changed over the years. Currently we recommend duplex sonography in combination with intra- and extracranial magnetic resonance angiography (MRA). Concurrent coronary artery disease is a major consideration in the perioperative management, and the use of a specific algorithm is recommended. Surgery is performed under general anaesthesia with intraoperative monitoring such as electroencephalography (EEG) and transcranial Doppler (TCD). A temporary intraluminal shunt is used selectively if after cross-clamping the flow velocity in the middle cerebral artery (MCA) falls to below 30 to 40% of baseline. For years we employed routine barbiturate neuroprotection during cross-clamping. At the present time we use barbiturate selectively, if the flow velocity in the MCA falls to below 30 to 40% of baseline and if the use of a temporary intraluminal shunt is not possible due to difficult anatomic conditions. The reason to abandon systematic barbiturate protection was to accelerate recovery from anaesthesia. Our patients are monitored overnight on the ICU or a surveillance unit. Routine hospitalization after surgery is 5 to 7 days with a control duplex sonography being performed prior to discharge. A number of details with regard to surgical technique and perioperative management are a matter of discussion. Our surgical routine is described here step by step. Such management resulted in 6 major complications among the 402 cases with 4 of cardiopulmonary and 2 of cerebrovascular origin. For the future we can expect the development of percutaneous transluminal techniques competing with standard carotid endarterectomy. At the present time several comparative studies are under way. Irrespective of the technical approach to treat carotid stenosis, several other issues have to be clarified before long. One of the major unresolved items is the timing of treatment after completed stroke. In this regard prospective trials need to be performed. Although numerically not as important as carotid stenosis, vertebral artery (VA) and subclavian artery (SA) stenoses are more and more accepted as indication for surgical

Association of cerebral arteriovenous malformations and spontaneous occlusion of major feeding arteries: clinical and therapeutic implications

OBJECTIVE

The spontaneous occlusion of a cerebral arteriovenous malformation (AVM) occurs rarely. Occlusion of a parent artery feeding the AVM is even more rare, and its incidence is unknown. We undertook this study to determine the incidence of occlusion of a major artery feeding an AVM and to recommend a management strategy for such an AVM.

METHODS

We identified AVMs associated with an occluded artery by performing a retrospective angiographic analysis of 500 patients with AVMs who presented to Henry Ford Hospital from 1976 to 1998.

RESULTS

A review of the angiograms revealed that 7 (1.4%) of 500 patients with an AVM had occlusion of one or more major arteries feeding the nidus. In four patients, an internal carotid artery and its bifurcation were occluded; in two patients, the M1 segment of the middle cerebral artery was occluded, and in one patient, a vertebral artery was occluded. Pial collaterals and/or a moyamoya pattern of anastomoses developed in all patients, with the exception of one who had vertebral artery occlusion. Five patients underwent definitive treatment: one received radiosurgery, and four underwent surgical excision. One of the surgically treated patients died of complications from excessive blood loss and coagulopathy, but the other three had no postoperative complications.

CONCLUSION

The occlusion of a major artery feeding an AVM occurs rarely (1.4%). These AVMs are moderate to large in size (>3 cm). To prevent collateral flow-related complications of cortical "steal" and hemorrhage, as well as the usual risk of hemorrhage from the AVM itself, surgical management should be considered for these AVMs.

Carotid artery thrombus associated with severe iron-deficiency anemia and thrombocytosis

BACKGROUND

Thrombus within the carotid artery usually occurs in vessels with severe atherosclerotic disease and may embolize to cause transient ischemic attacks and cerebral infarctions. The risk factors for carotid artery thrombus formation in the absence of atherosclerosis are not well characterized. A case series is presented that suggests an association of carotid artery thrombus with severe iron-deficiency anemia and thrombocytosis.

CASE DESCRIPTIONS

We describe three women with severe iron-deficiency anemia and thrombocytosis secondary to menorrhagia who developed carotid artery thrombi. Thrombi were detected radiographically. The patients were treated with anticoagulation and antiplatelet therapy. In two patients, follow-up neuroimaging 10 to 14 days later demonstrated resolution of the thrombus and no identifiable vascular disease.

CONCLUSIONS

Severe iron-deficiency anemia with thrombocytosis may be a risk factor for carotid artery thrombus formation. Medical management with anticoagulation and antiplatelet therapy is a reasonable approach for these patients while the thrombus resolves.

Free-floating thrombus of the extracranial internal carotid artery

Free-floating clots of the extracranial internal carotid artery are generally considered as surgical emergencies. This retrospective study analyzes six free-floating clots diagnosed by arteriography. Three of these patients had a fixed stroke while the other three had an evolving stroke. Three patients had antecedent ocular or hemispheric transient ischemic attacks. The causes of free-floating clots in the internal carotid artery were atheromatous stenosis in two cases, ulcerated plaque in three cases, and carotid artery dissection in one. All six patients were seen late, approximately 15 hours after their neurologic accident. They were treated with intravenous heparin over a two to five week period. Repeat arteriograms demonstrated complete clot lysis in four instances, while partial lysis was seen in one case. Moderate extension of thrombus occurred in one case only. No further neurologic complications were noted during the treatment by heparin. As indicated by follow-up arteriographic findings, secondary surgery was performed for major carotid lesions and residual clots in five cases. The free-floating thrombus syndrome of the carotid artery should not be considered as a surgical emergency when discovered late in the wake of an acute neurologic accident.

Prospective study of the effectiveness and durability of carotid endarterectomy

In a series of 252 consecutive patients who underwent 282 carotid endarterectomies, we conducted clinical and angiographic follow-up for 2 to 6 years (mean, 3.2 years). Digital subtraction angiography (DSA) was done postoperatively in 95% of cases. Clinical follow-up was achieved in 97% of cases, and DSA follow-up was obtained in 66% of cases. The overall group had a 1% operative minor morbidity (three cases of minimal new neurologic deficit), no major morbidity, and a 0.7% mortality (one death from stroke and one from myocardial infarction). Complications correlated well with the patient's preoperative risk category. During follow-up, 10 minor strokes, only 1 of which was attributable to the reconstructed artery, and 10 transient ischemic attacks, 3 of which were presumably related to recurrent stenosis, occurred. Asymptomatic mild to moderate restenosis of the internal carotid or common carotid artery was identified in 10% of follow-up DSAs and severe stenosis or occlusion in 3%. Stenosis in the opposite common carotid or internal carotid artery progressed in 48 cases (26% of follow-up DSAs and ultrasound studies), and 10 of these became symptomatic. An actuarial analysis of patients who had endarterectomy indicated that the cumulative probability of ipsilateral stroke was 1.5% at 1 month and 2% at 5 years. The cumulative probability of ipsilateral stroke, transient ischemic attack, or reversible ischemic neurologic deficit was 4% at 1 month and 8% at 5 years or less than 1% per year after the first month, with censoring at the time of the second surgical procedure.

Local fibrinolytic therapy in ischemic carotid pathology

Sixteen patients underwent local fibrinolytic therapy for thrombosis or embolism of the main trunk or intracranial branches of the internal carotid artery. There were eight cases of complete thrombosis of the internal carotid artery, five proximal stenoses of the internal carotid artery with extensive thrombus, one thrombus of the carotid siphon and two middle cerebral artery emboli. Indications for treatment included transient ischemic attacks in 11 cases, cerebral ischemia after carotid arteriography in two cases, and after surgery for atheromatous lesions of the carotid bifurcation in three cases. The fibrinolytic therapy was initiated during carotid surgery in three cases, where extended thrombosis of the internal carotid artery was discovered, which was inaccessible to a Fogarty catheter. The other 13 cases were treated during arteriography procedures. Lysis of the clot was always obtained. One patient died of hematoma of the frontal lobe. All other patients survived and showed neurologic improvement. The neurologic outcome was dependent on the duration and the degree of initial ischemia. Fibrinolytic therapy appears to be beneficial therapy for certain cases of cerebral ischemia.

Intraluminal thrombus in the cerebral circulation. Implications for surgical management

Thrombi defined as intraluminal filling defects detected by angiography were identified in 30 patients (29 in the carotid system, one in the vertebral artery). Stroke was the presentation ipsilateral to the thrombus in 22 patients (12 had previous transient ischemic attacks), transient ischemic attacks occurred alone in seven cases, and one patient was asymptomatic. Angiography revealed a severe stenosis in association with the thrombus in 23 patients, a moderate stenosis in four patients, and, in the three patients with only minimal stenosis presumably due to atherosclerosis, there was evidence for a coagulopathy. Sixteen of the 30 patients were operated on urgently, 10 within 24 hours of detection of the thrombus. Twelve of these 16 surgical patients were given anticoagulation before surgery. At endarterectomy, thrombus was identified in 11 of the 14 surgical patients in whom the thrombus was accessible; the other two surgical patients had intracranial thrombus only. In this group, four of 11 surgical patients with accessible thrombi suffered perioperative episodes of new or larger infarction. Fourteen of the 30 patients initially received medical management with no complication. Eight of these 14 medical patients had repeat angiography; seven exhibited complete resolution of thrombus, and six of these seven patients subsequently underwent delayed endarterectomy for the stenosis. No thrombus was identified at surgery in any of the six. One of the six delayed surgery patients suffered a perioperative stroke. Although these numbers are small, reflecting the rarity of thrombus demonstrated by angiography, undetected thrombus is often found at endarterectomy. Its presence may increase operative risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraluminal clot of the carotid artery. A clinical-angiographic correlation of nine patients and literature review

Between March 1980 and March 1985, intraluminal thrombi of the carotid artery were noted in 9 of 2250 patients undergoing arteriography for symptoms of cerebral ischemia. Five patients had transient ischemic attacks, and four had acute cerebral infarctions. Six patients had surgery, but a thrombus was only found in five. Two patients had new neurological deficits after surgery. Three patients received only medical therapy, and all remained stable. Intraluminal thrombus is an uncommon radiographic finding in patients with cerebral ischemia. Not all clots are confirmed at operation. The optimal treatment of this situation is not known. Both surgical and medical treatments deserve further investigation.