Carotid Stenting as Definitive Treatment for Free Floating Thrombus-Review of 7 Cases

Optical Coherence Tomography-Guided Stenting for Common Carotid Free-Floating Thrombus

CLINICAL IMPACT

Digital subtraction angiography (DSA) has traditionally been considered an effective method for visualizing carotid free-floating thrombus (CFFT), but it falls short in providing detailed structures of the lumen and the composition of thrombi, making it challenging to determine the etiology. Intravascular optical coherence tomography (OCT) is a valuable adjunct to DSA that can precisely evaluate the characteristics of the intrinsic vessel wall and accurately distinguish between red and white thrombus, providing clues to the etiology of CFFTs. Moreover, OCT not only precisely determined the scope of a floating thrombus but also provided guidance for decision-making in endovascular treatment.

Anticoagulants versus Antiplatelet Treatment in the Medical Management of Carotid Floating Thrombus

BACKGROUND

Carotid free-floating thrombus (CFT) is a rare cause of stroke describing an intraluminal thrombus that is loosely associated with the arterial wall and manifesting as a filling defect fully surrounded by flow on vascular imaging. Unfortunately, there is no clear consensus among experts on the ideal treatment for this pathology.

METHODS

Retrospective analysis of acute ischemic stroke (AIS) and transient ischemic attack (TIA) patients diagnosed with CFT on computed tomography angiogram (CTA) between January 2015-March 2023. We aimed to compare two treatment regimens: anticoagulation (ACT) and antiplatelet (APT) in the treatment of CFT. APT regimens included the use of dual or single antiplatelets (DAPT or SAPT; aspirin, clopidogrel and ticagrelor) and ACT regimens included the use of direct oral anticoagulants, warfarin, heparin or low molecular weight heparin +/- ASA. Patients that underwent mechanical thrombectomy were excluded.

RESULTS

During study time there were 8252 acute ischemic stroke hospitalizations, of which 135 (1.63 %) patients were diagnosed with CFT. Sixty-six patients were included in our analysis. Patients assigned to APT were older (60.41years ± 12.82;p < 0.01). Other demographic variables were similar between ACT and APT groups. Complete CFT resolution on repeat vascular imaging was numerically higher at 30 days (58.8 vs 31.6 %, respectively; p = 0.1) and at latest follow-up (70.8 vs 50 %; p = 0.1) on ACT vs APT, respectively without reaching statistical significance. Similarly, there was numerically higher rates of any ICH with ACT compared to APT but it did not achieve statistical significance (27.6 % vs 13.5 %; p = 0.5). There were similar rates of PH1/2 hemorrhagic transformation, independence at discharge and similar hospital length of stay between ACT and APT groups. Patients assigned to APT were more likely to be discharged on their assigned treatment compared to those assigned to ACT (86.5 vs 55.2 %; p < 0.001). The rate of 30-day recurrent stroke was comparable among ACT and APT at 30 days (3.4 vs 0 %; p = 0.1, respectively). Subgroup analysis comparing exclusive ACT vs Dual APT lead to similar results.

CONCLUSION

Our study showed comparable efficacy and safety outcomes in CFT patients who were exclusively managed medically with ACT vs APT. Larger prospective studies are needed.

Findings of Angiography and Carotid Vessel Wall Imaging Associated with Post-Procedural Clinical Events after Carotid Artery Stenting

PURPOSE

Vessel wall imaging (VWI) for carotid plaque is better for detecting unstable carotid plaque such as intraplaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), and thin/ruptured fibrous cap. However, the role of VWI before carotid artery stenting (CAS) is unclear. Thus, this study aimed to determine the findings of symptomatic carotid stenosis before CAS on angiography and carotid VWI and to evaluate the imaging findings associated with post-procedural clinical events after CAS.

MATERIALS AND METHODS

This retrospective study included 173 consecutive patients who underwent carotid VWI, CAS, and post-procedural diffusion-weighted imaging (DWI) after CAS. Findings of unstable plaque on carotid VWI and unstable findings on angiography were analyzed. We also analyzed the incidence of post-procedural clinical events, any stroke, myocardial infarction (MI), and death within 30 days of CAS.

RESULTS

Of 173 patients, 101 (58.4%) had initial ischemic symptoms and positive findings on DWI. Symptomatic patients were significantly higher in patients with IPH than in patients without IPH (62.4% vs. 45.8%, P=0.031). Degree of stenosis, thrombus of the stenotic lesion, flow delay of internal carotid artery, and flow arrest by filter thrombus had significantly higher prevalence in the symptomatic group. Twenty patients (11.6%) had post-procedural clinical events such as any stroke, clinical symptoms, and/or MI. Hyperlipidemia and intraluminal thrombus on angiography were identified as significant factors influencing post-procedural events after CAS.

CONCLUSION

An intraluminal thrombus on angiography was identified as a significant factor influencing post-procedural clinical events after CAS.

Carotid Free-Floating Thrombus Treated With a Combined Technique Using Embotrap III for Distal Protection

Carotid free-floating thrombus (FFT) is a rare condition in patients with acute ischemic stroke. Recently, endovascular therapy for carotid FFT has been increasingly reported, but the strategy has not yet been established. We report a case of an acute stroke patient with a carotid FFT, who was successfully treated with a combination of the direct aspiration first-pass technique (ADAPT) and the Embotrap III (Cerenovus, Irvine, CA), specifically designed to prevent distal embolization. We propose the utility of distal embolic protection with Embotrap III for the treatment of patients with carotid FFT. A 71-year-old man who presented with sudden left hemiparesis was admitted to our hospital. Ultrasonography on admission revealed severe stenosis and an FFT at the origin of the right internal carotid artery. Thrombectomy with an aspiration catheter, accompanied by a stent retriever with distal basket Embotrap III for distal protection, was performed. After the FFT was safely aspirated, a carotid Wallstent (Boston Scientific, Marlborough, MA) was deployed in the stenosis. Follow-up ultrasonography showed neither FFT nor in-stent protrusion. The patient did not experience recurrence, as per clinical or radiological findings, and was discharged on day 11 without any neurological deficits. Embotrap III may be useful for a patient with a carotid FFT as distal protection during mechanical thrombectomies.

Contrast-enhanced ultrasound reveals free-floating thrombus in carotid artery: The cause of stroke is surprisingly plaque rupture

BACKGROUND

Acute stroke poses a serious threat to people's health. The occurrence of a thrombus following the rupture of vulnerable plaques in the carotid artery is a significant contributor to the development of stroke. In previous case reports, it has been challenging to visualize tiny ulcerations within carotid artery plaques using computed tomography angiography (CTA) and digital subtraction angiography (DSA), even when the rupture of the plaque leads to the formation of a free-floating thrombus (FFT). However, in this particular case, contrast-enhanced ultrasound (CEUS) was able to overcome this limitation and provide a more precise assessment, confirming that the FFT formation was indeed a result of plaque rupture rather than any other potential causes. Cases that utilize CEUS to visualize the formation of ulcers and FFT resulting from plaque rupture are even more rare. As such, we present this case to shed light on this infrequent phenomenon.

CASE SUMMARY

In this case study, we present a 65-year-old male patient who was admitted to the hospital due to headache and abnormal mental behavior for one day. During the routine cervical artery ultrasound examination upon admission, we detected the presence of plaque in the right internal carotid artery of the patient, resulting in luminal stenosis. Additionally, we observed suspected hypoechoic material at the distal end of the plaque. After undergoing CEUS examination, it was definitively determined that an ulcer had formed and a FFT had developed due to the rupture of carotid artery plaque. Subsequent CTA and DSA examinations further confirmed the presence of the FFT. The magnetic resonance imaging (MRI) reveals an acute lacunar infarction in the head of the right caput nuclei caudate, which strengthens the potential link between the patient's neurological and psychiatric symptoms observed during admission. The patient received prompt antiplatelet therapy and underwent cervical artery stenting surgery with the assistance of a distal embolic protection device. Following the procedure, the patient was discharged on the fourth day and experienced a complete recovery.

CONCLUSION

CEUS is a valuable tool for visualizing FFT resulting from the rupture of vulnerable plaques in the carotid artery.

Triple Stentriever "Bouquet" Deployment with Zoom 88 Large-Bore Aspiration and Walrus Balloon-Guide Catheter for the Definitive Thrombectomy of a Carotid Free-Floating Thrombus

Formation of a carotid free-floating thrombus (CFFT) is a rare and life-threatening condition without an optimal management plan. A 78-year-old woman with a history of prior right internal carotid artery (ICA) mechanical thrombectomy and antiplatelet noncompliance presented with transient ischemic attacks secondary to a recurrent CFFT in the right ICA. Given her symptoms and recurrent CFFT, endovascular mechanical thrombectomy was performed. A balloon guide-catheter (BGC) and a Zoom 88 distal access catheter were brought into the right distal common carotid artery and proximal ICA bulb, respectively. Three 0.021-inch microcatheters, each loaded with a unique stentriever, were navigated beyond the thrombus into the upper cervical ICA and deployed in a bouquet fashion. The BGC was inflated to achieve flow arrest, and the Zoom 88 aspiration catheter was tracked over the three bouquet stentrievers to ingest the thrombus. Follow-up angiography demonstrated recanalization of the proximal cervical ICA without evidence of residual thrombus. Twenty-four-hour postoperative computed tomography imaging did not reveal any evidence of new infarction. The patient was discharged home with an intact neurological examination, compliant on aspirin and apixaban. We demonstrate a novel technique utilizing a large-bore catheter with a triple stentriever "bouquet" to thrombectomize a CFFT.

Symptomatic carotid artery intraluminal thrombus: risk of medical management failure and distal embolization

BACKGROUND

Carotid artery intraluminal thrombus (ILT), or free-floating thrombus, is an uncommon cerebrovascular entity with considerable equipoise regarding its clinical management. Likewise, in patients treated with medical management (MM), distal embolization and/or intracranial hemorrhage (ICH) may still occur.

METHODS

All patients with symptomatic ILT from 2016 to 2023 were identified from our tertiary care institution. Patients with MM failure (recurrent cerebral ischemia and/or symptomatic ICH) were compared with patients with MM non-failure. Differences in ILT volume and length were calculated. Receiver operator characteristic (ROC) curve analysis was used to identify the cut-off volume and length for risk of MM failure.

RESULTS

In total, 45 patients with ILT were identified with 41 treated with frontline MM. Of these 41 patients treated with MM, seven (17%) had MM failure with six (14.6%) having new embolic stroke and one (2.3%) with symptomatic ICH. Patients with MM failure had a significantly higher mean thrombus volume than MM non-failure patients (257 mm3 vs 59.6 mm3, P=0.0006). Likewise, patients with MM failure had significantly longer thrombus on average (21 mm vs 6.6 mm, P=0.0009). ROC curve analysis showed that an ILT volume of 90 mm3 resulted in a sensitivity of 71.4% and specificity of 85.3% for MM failure (AUC 0.775; CI 0.55 to 1.0, P=0.023).

CONCLUSIONS

Carotid ILTs that fail MM are significantly larger and longer. These findings suggest that a thrombus volume of 90 mm3 may serve as a guide for intervention with good sensitivity and specificity for risk of MM failure.

Stent retrieval for free-floating thrombus attached to carotid artery stenosis: A report of two cases

Background

We report two cases who underwent mechanical thrombectomy using a stent retriever in advance of urgent carotid artery stenting (CAS) for carotid artery stenosis with free-floating thrombus (FFT).

Case Description

Two patients showing symptomatic carotid artery stenosis with FFT underwent urgent endovascular surgery due to progressive neurological symptoms. The first case showed an FFT with 70% internal carotid artery (ICA) stenosis. After the completion of the common and external carotid artery balloon and distal ICA filter protection, we deployed a 6-mm-diameter stent retriever in the distal part of the stenosis. The white thrombus was retrieved; the angiographic shadow of the FFT disappeared; and CAS was performed. In the second case, due to a 90% severe stenosis lesion with FFT, balloon angioplasty was performed on the lesion using the push wire of the stent retriever. After angioplasty, the stent retriever was smoothly retrieved, and CAS was performed. Postoperative magnetic resonance imaging showed an increase in cerebral embolism in the first case; however, the patient's neurological symptoms improved. The second case showed in-stent plaque protrusion and required two additional stent placements; the patient showed no worsening of his neurological symptoms.

Conclusion

In cases of carotid artery stenosis with FFT, it is technically possible to retrieve a thrombus with a stent retriever. Although thrombus removal may help reduce the risk of ischemic complications in a series of urgent CAS procedures, there are concerns such as mechanical irritation to the carotid artery plaque, and its indications and alternative treatments should be carefully considered.

Mechanical thrombectomy and carotid artery stenting for stenosis of the internal carotid artery with free-floating thrombosis: illustrative case

BACKGROUND

The authors report a case in which mechanical thrombectomy and carotid artery stenting (CAS) were performed for acute cerebral infarction with free-floating thrombosis (FFT) in left internal carotid artery (ICA) stenosis. Good results were obtained.

OBSERVATIONS

A 63-year-old man developed sudden disturbance of consciousness and right hemiplegia. He was transported to the authors’ hospital by an emergency vehicle. Head magnetic resonance imaging showed acute cerebral infarction in the left middle cerebral artery region, and magnetic resonance angiography showed poor vascular flow beyond the left ICA. Emergency angiography revealed severe stenosis at the origin of the left ICA and a free-floating thrombus attached to the stenosis and extending to the peripheral side. Percutaneous transluminal angioplasty (PTA) was performed on the stenosis with proximal protection, the thrombus was aspirated under reversal flow, and CAS was performed without exacerbation of clinical symptoms.

LESSONS

PTA, thrombus aspiration, and CAS under reversal flow may be effective treatments for FFT caused by ICA stenosis.

A Case of Internal Carotid Artery Occlusion Caused by En Bloc Distal Embolization of Carotid Free-Floating Thrombus Treated by Mechanical Thrombectomy

Objective

We report a case of internal carotid artery (ICA) occlusion caused by en bloc distal embolization of carotid free-floating thrombus (FFT) treated by mechanical thrombectomy.

Case Presentation

A 57-year-old woman was brought to our hospital with dysarthria, right hemiparesis, and motor aphasia. MRI and MRA revealed acute infarction due to middle cerebral artery occlusion. Carotid ultrasonography demonstrated a pedunculated mobile plaque in the left ICA. We diagnosed embolic infarction due to the carotid FFT and started medical treatment. However, on the second hospital day, the carotid FFT detached from the arterial wall en bloc, resulting in left ICA occlusion. The occluded ICA was successfully recanalized by mechanical thrombectomy.

Conclusion

FFT is associated with a high risk of embolic ischemic stroke and the primary treatment strategy must be carefully considered.

Huge Free-Floating Thrombus in the Internal Carotid Artery Under Duplex Ultrasound Surveillance

Carotid free-floating thrombus (FFT) is an unusual finding in acute ischemic stroke. Atherosclerosis is the most common etiology of FFT formation.

Free-Floating Thrombus in the Distal Internal Carotid Artery Causing a Stroke

We present a patient suffering from a stroke with a free-floating thrombus extending up to the distal internal carotid artery. The thrombus was totally resolved after a 2-week anticoagulation regimen without leaving behind any severe residual stenosis in the carotid bulb. The optimal treatment of this rare condition remains uncertain. We report some important treatment strategies that have been used in the literature, emphasizing the anticoagulation as the mainstay of therapy. Immediate surgical and interventional manipulations carry the risk of thrombus dislodgement and embolization and should be considered if there are recurrent symptoms despite medical management.

A Case of Coincidental Free Floating Thrombus in the Vertebral Artery in a Patient Presenting with an Anterior Circulation Stroke and Literature Review

Free-floating thrombus (FFT) is a rare condition with unknown etiology as described by many case reports presented in previous literature. The patients usually present symptomatically while the other few patients remain asymptomatic and are usually discovered incidentally on computed tomography angiography (CTA). Most of the cases reported in the literature are of FFT in the internal carotid artery. We present a 59-year-old female as a case of FFT in the vertebral artery which was coincidently discovered on CTA in a patient initially presenting with an anterior circulation stroke. This case highlights the importance of early contrast-based vascular imaging in patients presenting with large vessel strokes that are cardioembolic in nature and the unique utilization of a direct aspiration first pass technique (ADAPT) for revascularization. Included herein an extensive review of the literature about the decision making in patients with FFT and a devised proposed practical approach to this entity.