Computed tomography angiography evaluation of internal carotid artery free-floating thrombus—single-center diagnosis, false-positives, and follow-up

Endovascular Thrombectomy for a Progressive Stroke Patient With a High-Burden Carotid Free-Floating Thrombus

Carotid free-floating thrombus (FFT) is a rare cause of acute ischemic events. The optimal management of carotid FFT remains unclear. The optimal and individualized management of carotid FFT should be determined based on the underlying etiology, clinical manifestation, and imaging characteristics. we reported a case with endovascular thrombectomy for a progressive stroke patient with a high-burden carotid free-floating thrombus. ANN NEUROL 2024;95:362-364.

Differentiating Carotid Free-Floating Thrombus From Atheromatous Plaque Using Intraluminal Filling Defect Length on CTA: A Validation Study

OBJECTIVE

To validate a previously proposed filling defect length threshold of >3.8 mm on CT angiography (CTA) to discriminate between free-floating thrombus (FFT) and plaque of atheroma.

METHODS

This was a prospective multicenter observational study of 100 participants presenting with TIA/stroke symptoms and a carotid intraluminal filling defect on initial CTA. Follow-up CTA was obtained within 1 week and at weeks 2 and 4 if the intraluminal filling defect was unchanged in length. Resolution or decreased length was diagnostic of FFT, whereas its static appearance after 4 weeks was indicative of plaque. Diagnostic accuracy of FFT length was assessed by receiver operating characteristic analysis.

RESULTS

Ninety-five participants (mean [SD] age 68 [13] years, 61 men, 83 participants with FFT, 12 participants with a plaque) were evaluated. The >3.8-mm threshold had a sensitivity of 88% (73 of 83) (95% confidence interval [CI] 78%-94%) and specificity of 83% (10 of 12) (95% CI 51%-97%) (area under the curve 0.91, p < 0.001) for the diagnosis of FFT. The optimal length threshold was >3.64 mm with a sensitivity of 89% (74 of 83) (95% CI 80%-95%) and specificity of 83% (10 of 12) (95% CI 51%-97%). Adjusted logistic regression showed that every 1-mm increase in intraluminal filling defect length is associated with an increase in odds of FFT of 4.6 (95% CI 1.9-11.1, p = 0.01).

CONCLUSION

CTA enables accurate differentiation of FFT vs plaque using craniocaudal length thresholds.

TRIAL REGISTRATION INFORMATION

ClinicalTrials.gov Identifier: NCT02405845.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that in patients with TIA/stroke symptoms, the presence of CTA-identified filling defects of lengths >3.8 mm accurately discriminates FFT from atheromatous plaque.

Surgical Thromboendarterectomy for Free-Floating Thrombus Associated with Cervical Carotid Artery Dissection: A Case Report

BACKGROUND

Free-floating thrombus (FFT) of the cervical carotid artery is a rare but critical condition leading to stroke. The most common underlying pathology is atherosclerotic plaque; nonatherosclerotic pathologies are much rarer. Here we report a case of FFT associated with cervical carotid artery dissection that was successfully treated by surgical thromboendarterectomy.

METHODS

A 51-year-old man presented with headache, pain in the left neck, and amaurosis fugax. Magnetic resonance angiography revealed mild stenosis in the bifurcation of the left carotid artery. The stenotic lesion was considered as a possible dissection because of the normal appearance of the vessel 2 years ago and its clinical presentation. Oral aspirin was initiated with the diagnosis of transient ischemic attack. Two weeks later, ultrasound was planned for further examination, which demonstrated a massive FFT with intramural hematoma in the lesion. Because FFT was present despite taking aspirin, surgical thromboendarterectomy was performed to prevent further ischemic events.

RESULTS

Intraoperative findings revealed that FFT was the thrombus protruding from the intramural hematoma caused by arterial dissection. After the whole dissected layer was removed, the residual lumen was reinforced by multiple tacking sutures to prevent recurrence of dissection. No further ischemic events and recurrence occurred during the 1-year of follow-up after the surgery.

CONCLUSIONS

When managing patients with carotid artery dissection, the formation of FFT should be considered as a possible critical feature. Surgical thromboendarterectomy with intimal tacking sutures might be an option for the treatment, ensuring immediate, preventive effects against the risk of cerebral embolism.

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.

Management of free-floating thrombus within the arcus aorta and supra-aortic arteries

INTRODUCTION

Clinical management strategy and the best treatment option of free floating thrombus (FFT), detected in patients with acute ischemic cerebrovascular diseases is still uncertain due to the rarity of these conditions. Recent studies emphasize that FFT within cerebral vessels may not be a surgical emergency since complete dissolution without any further neurologic progression occurred in 86% of patients treated medically. The aim of this study was to investigate the effect of medical treatment on the fate of thrombus and the clinical status in acute cerebrovascular event patients with detected FFT in the artery feeding the compromised brain territory at the time of diagnosis.

MATERIALS AND METHODS

We have retrospectively reviewed the initial and follow up computed tomography angiography, diffusion-weighted magnetic resonance imaging examinations of 37 acute ischemic stroke patients with detected FFT and treated medically. The patients were evaluated for any change of the FFT, residual stenosis after the FFT shrunk or disappeared and neurologic outcome.

RESULTS

FFT was located in cervical carotid artery, intracranial artery and arcus aorta in 23, 6 and 5 of the patients respectively. Dissection accompanied the FFT in 3 patients. Recanalization was maintained in 34 patients however, three of them suffered from new infarctions. A total occlusion was detected in three patients. Two of them had new infarcts while one was stable during clinical follow-up period.

CONCLUSION

The results of our retrospective study have shown that FFT in the proximal aorta and supra-aortic arteries tend to resolve with anticoagulant and/or antiplatelet treatment without causing recurrent adverse events in most of the cases. Furthermore, resolution of the clot seems to provide a safer ground for a recanalization procedure like stenting or endarterectomy if needed.

Can shape analysis differentiate free-floating internal carotid artery thrombus from atherosclerotic plaque in patients evaluated with CTA for stroke or transient ischemic attack?

RATIONALE AND OBJECTIVES

Patients presenting with transient ischemic attack or stroke may have symptom-related lesions on acute computed tomography angiography (CTA) such as free-floating intraluminal thrombus (FFT). It is difficult to distinguish FFT from carotid plaque, but the distinction is critical as management differs. By contouring the shape of these vascular lesions ("virtual endarterectomy"), advanced morphometric analysis can be performed. The objective of our study is to determine whether quantitative shape analysis can accurately differentiate FFT from atherosclerotic plaque.

MATERIALS AND METHODS

We collected 23 consecutive cases of suspected carotid FFT seen on CTA (13 men, 65 ± 10 years; 10 women, 65.5 ± 8.8 years). True-positive FFT cases (FFT+) were defined as filling defects resolving with anticoagulant therapy versus false-positives (FFT-), which remained unchanged. Lesion volumes were extracted from CTA images and quantitative shape descriptors were computed. The five most discriminative features were used to construct receiver operator characteristic (ROC) curves and to generate three machine-learning classifiers. Average classification accuracy was determined by cross-validation.

RESULTS

Follow-up imaging confirmed sixteen FFT+ and seven FFT- cases. Five shape descriptors delineated FFT+ from FFT- cases. The logistic regression model produced from combining all five shape features demonstrated a sensitivity of 87.5% and a specificity of 71.4% with an area under the ROC curve = 0.85 ± 0.09. Average accuracy for each classifier ranged from 65.2%-76.4%.

CONCLUSIONS

We identified five quantitative shape descriptors of carotid FFT. This shape "signature" shows potential for supplementing conventional lesion characterization in cases of suspected FFT.