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Objective: To evaluate the efficacy of a novel coated stent in the treatment of intracranial pseudoaneurysm. Methods: MEDLINE, EMBASE, and PubMed databases were searched for literature published between 1990 and April 2022 according to PRISMA guidelines. All studies with ≥10 patients reporting successful implantation of Willis covered stent, therapeutic effect, complications, and postoperative follow-up were included. The combined incidence and corresponding 95% confidence intervals were assessed using a generalized linear mixed method and random effects model. Results: Five studies (116 patients with pseudoaneurysms) were included. The experimental groups in the selected studies showed a combined technical success rate of 81.03% (OR=18.31, 95% CI=9.39-35.69, I2=79%, P

Blood blister-like aneurysms (BBAs) are fragile and difficult to treat. However, the optimal treatment has yet to be determined. Pipeline embolization devices and Willis covered stent implementation are still controversial strategies for treating BBA. Herein, we report a case of recurrent BBA successfully treated with a Willis covered stent. A long-term follow-up angiography after the procedure indicated complete occlusion of the aneurysm. This case demonstrates the safety and efficacy of applying the Wills cover stent in the treatment of recurrent BBA after Pipeline implantation.

Background: More data is needed on the short- and medium-term efficacy and safety of the Willis covered stent in treating distal internal carotid artery (DICA) aneurysms and vertebral artery dissecting aneurysms (VADAs). Methods: Records of all 42 patients with DICA aneurysms or VADAs treated with the Willis covered stents at our institute between July 2014 and January 2019 were retrospectively examined. The patients' demographic information, symptoms, diagnosis, treatment procedure, immediate and follow-up clinical and angiographic outcomes were extracted. Results: 46 Willis covered stents were successfully implanted in all of the 42 patients (total 43 aneurysms). Immediate complete aneurysm occlusion was achieved in 37 patients (38 aneurysms) (88.4%), and endoleak occurred to 5 patients (5 aneurysms) (11.6%). 2 patients died post-operatively from procedure-related complications, another one died from reasons unrelated to the procedure. Among the remaining 39 patients, non-lethal complications occurred in 4 patients including ptosis and diplopia of the right eye, intra-operative hemorrhage and carotid cavernous fistulas (CCF). Angiographic and clinical follow-ups (means ± standard deviation: 8.8 ± 5.3 months) were done for 32 patients (33 aneurysms). Complete occlusion was maintained in all of the 33 aneurysms. 2 of the 32 patients had significant though asymptomatic parent artery (PA) occlusion. No ischemic or hemorrhagic event occurred during the follow-up period. The modified Rankin Scale (mRS) score was 0 in 31 patients and 1 in the remaining 1 patient. Conclusions: The Willis covered stent could be a safe and effective treatment for complex DICA aneurysms with excellent durability. In addition, the Willis covered stent treated all of the 3 cases of VADAs in the study with complete success without any complications, however, as the number of the VADA cases was small, more cases are needed to further confirm the efficacy and safety of the Willis covered stent in treating VADAs. [ABSTRACT FROM AUTHOR]

Dan Lu,1,* Tao Ma,1,* Gemin Zhu,2,* Tao Zhang,3 Naibing Wang,1 Hui Lei,2 Jing Sui,1 Zhiguo Wang,1 Shiming He,1 Lei Chen,1 Jianping Deng3 1Department of Neurosurgery, Xi’an International Medical Center Hospital, Xi’an, People’s Republic of China; 2Department of Neurology, Xi’an Central Hospital, Xi’an, People’s Republic of China; 3Department of Neurosurgery, Tangdu Hospital, Air Force Medical University, Xi’an, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jianping DengDepartment of Neurosurgery, Tangdu Hospital, Air Force Medical University, Xi’an, People’s Republic of China, Email 13991139395@163.com; Lei ChenDepartment of Neurosurgery, Xi’an International Medical Center Hospital, Xi’an, People’s Republic of China, Email clzx1986@126.comObjective: This work aimed to retrospectively analyze Willis covered stent (WCS)’s therapeutic efficacy in intracranial pseudoaneurysms (PSAs) of the internal carotid artery (ICA).Methods: Between June 2018 and July 2021, 56 individuals with intracranial PSAs of the ICA treated with WCS in three centers were included to analyze information regarding medical records, operative parameters, imaging findings and follow-up data.Results: All WCSs were successfully targeted to the ICA lesions. Total exclusion of PSA was found in 53 cases (94.6%) right upon surgery, and mild endoleak into the aneurysm remained in 3 cases (5.4%). Intraoperative thrombosis occurred in 1 case (1.8%), and tirofiban was utilized for recanalization. Follow-up by angiography showed total aneurysm occlusion in the total number of individuals, including in the 3 above cases with residual endoleak. In-stent stenosis occurred in 7 (12.5%) patients. No stent-related ischemic event was encountered. Predictive factors of late in-stent stenosis following WCS implantation in this patient group were irregular post-operative antiplatelet treatment (p = 0.015) and C4-C5 segment of the ICA (p = 0.043).Conclusion: WCSs are effective in treating intracranial PSAs of the ICA.Keywords: Willis covered stent, intracranial pseudoaneurysms, internal carotid artery, endoleak, in-stent stenosis

The optimal treatment for blood blister-like aneurysm (BBA) has not yet been determined, and BBA has a high recurrence rate after stent-assisted embolization. The purpose of the present study was to evaluate the safety and feasibility of patients with BBA rupture in the acute phase or patients with BBA who have recurrence after stent-assisted coil embolization. Eight patients (8 women, mean age 50.3 ± 3.7 years) who presented with ruptured BBA or recurrence BBA that had been treated by stent-assisted embolization (5 patients after primary treatment of stent-assisted embolization) were retrospectively reviewed. Clinical follow-up was performed at 1 year after endovascular treatment. All patients were successfully treated with the WCS, and immediate postoperative angiography showed that the aneurysms were completely isolated. The ophthalmic artery was covered by WCS in one patient; however, this patient did not show any clinical visual field or vision symptoms. Procedure-related complications such as aneurysm rupture, vasospasm, acute thrombosis, or thromboembolism did not occur in any case. All patients were followed up for 1 year after endovascular treatment, and they were in good condition without recurrence. One patient developed delayed bleeding at the right temporal lobe. All patients had good clinical prognosis (modified Rankin Scale score ≤ 2). WCS implantation may be a safe and feasible strategy for patients with BBA rupture in the acute phase and patients with BBA who have recurrence after stent-assisted coil embolization and is a promising option worth exploring. [ABSTRACT FROM AUTHOR]

Background: Symptomatic vertebral artery dissecting aneurysm (VADA) is a challenging disease with controversy on treatment strategy due to anatomic configuration and their nature. Moreover, the outcomes of reconstructive treatment have not been well established. Objective: To evaluate the safety and efficacy of reconstructive endovascular treatment (EVT) for symptomatic VADAs with Willis covered stent. Methods: We evaluated retrospectively 13 patients with symptomatic VADAs who treated with Willis covered stent, compared with stent-assisted coiling (SAC) on the characteristics, posttreatment course, angiographic and clinical follow-up outcomes at an average of 14.4 months (range, 3–48 months). Results: A total of 33 patients with symptomatic VADAs were reviewed, 23 of these patients with ruptured VADAs. The technical successful rate is 100% respectively in Willis covered stent (Group A) and SAC (Group B, n ​= ​20). The initial complete occlusion rate was significant higher in group A (100%) than group B (30%) (p ​ ​0.05). No obvious in-stent stenosis and no re-hemorrhage and delayed ischemic symptoms during the follow-up period. The final angiograms of all survived patients demonstrated the complete occlusion rate was higher in group A (100%) than group B (80%), but no significant statistical difference (p ​> ​0.05). Clinical outcomes were favorable in 31 (93.9%), severe disability occurred in one in group B, and only one death in group A. The final clinical outcomes were also not significant difference in the two groups (p ​> ​0.05). Conclusions: Our initial result demonstrated reconstructive EVT with Willis covered stent provides a viable approach for selected symptomatic VADAs involving the intracranial and extracranial segments, which is similar to favorable results with SAC. However, an expanded clinical experiences and larger cohort studies are needed.

Objective: To investigate the safety and efficacy of Willis covered stents (WCS) in the treatment of traumatic pseudoaneurysm of the cranial internal carotid artery (CICA).Methods: Fifteen patients with traumatic pseudoaneurysm of the intracranial segment of the ICA treated with the WCS system at our institution from 2013 to 2019 were analyzed retrospectively. Follow-up observation and digital subtraction angiography (DSA) examination were conducted ~6 months after the treatment.Results: DSA performed immediately after stent deployment revealed that complete occlusion of the lesion was achieved in 13 patients and that endoleak occurred in two patients. In 12 patients, postoperative DSA examination indicated that the lesions were completely occluded. In two patients who had a second stent implantation at the break of the ICA, traumatic ICA rupture was essentially completely obstructed in 1 patient. The endoleak remained in one patient with carotid cavernous sinus fistula because the placement of the second stent system was difficult with his ICA tortuosity. No recurrence of aneurysms, hemorrhage, or other lesions was observed, and the patients' parent arteries were patent without stenosis. No procedure-related complications or ischemic strokes occurred during the follow-up period of ~6 months.Conclusions: For treatment of traumatic pseudoaneurysm of the CICA, Willis covered stent implantation in some appropriate cases, is safe and effective. However, large-sample controlled studies and multicenter studies are needed for further confirmation.

Objective: To investigate the safety and efficacy of Willis covered stents (WCS) in the treatment of traumatic pseudoaneurysm of the cranial internal carotid artery (CICA). Methods: Fifteen patients with traumatic pseudoaneurysm of the intracranial segment of the ICA treated with the WCS system at our institution from 2013 to 2019 were analyzed retrospectively. Follow-up observation and digital subtraction angiography (DSA) examination were conducted ~6 months after the treatment. Results: DSA performed immediately after stent deployment revealed that complete occlusion of the lesion was achieved in 13 patients and that endoleak occurred in two patients. In 12 patients, postoperative DSA examination indicated that the lesions were completely occluded. In two patients who had a second stent implantation at the break of the ICA, traumatic ICA rupture was essentially completely obstructed in 1 patient. The endoleak remained in one patient with carotid cavernous sinus fistula because the placement of the second stent system was difficult with his ICA tortuosity. No recurrence of aneurysms, hemorrhage, or other lesions was observed, and the patients' parent arteries were patent without stenosis. No procedure-related complications or ischemic strokes occurred during the follow-up period of ~6 months. Conclusions: For treatment of traumatic pseudoaneurysm of the CICA, Willis covered stent implantation in some appropriate cases, is safe and effective. However, large-sample controlled studies and multicenter studies are needed for further confirmation. [ABSTRACT FROM AUTHOR]

Abstract Background The purpose of this study is to report the treatment approaches and postoperative outcomes of extracranial carotid artery aneurysms (ECAAs) and discuss the symptoms, related risk factors, etiology, diagnostic methods, treatments, and follow-up period complications. Case presentation We describe three patients with symptomatic extracranial carotid artery aneurysms; one of them was treated with end-to-end anastomosis of the extracranial internal carotid artery (EICA) after the resection of the aneurysm, while the other two patients were deployed with Willis covered stents in the extracranial internal carotid artery. All of the patients were in good condition when discharged home. After a mean follow-up period of 8 months, all the patients were alive and only one of them had the neurologic deficit. Additionally, we reviewed the relative literatures. Conclusion Both of the surgical and endovascular treatments have relatively satisfactory outcomes in ECAA patients. However, it is necessary to provide individualized treatments to different patients according to the characteristics of the aneurysms.

• Willis covered stent can achieved an satisfying complete occlusion rate for internal carotid artery aneurysms. • Procedure-related hemorrhagic and ischemic complications are not higher than other series with Willis covered stent. • Stent navigation failure, endoleak, and balloon occlusion test before procedure are not negligible. The purpose of this study was to retrospectively analyse the clinical and angiographic outcomes of Willis covered stent placement for unruptured aneurysms in internal carotid artery. Forty-six consecutive patients with internal carotid artery aneurysms (49 cases) were included to evaluate clinical and angiographic outcomes. Covered stent placement was successful in 47 cases, whereas stent navigation failed in 2 cases. Of the 49 aneurysms (mean aneurysm size, 7.9 mm), 5, 6, and 38 were located in the petrous, cavernous, and ophthalmic segments, respectively. Immediate angiography revealed complete aneurysm exclusion in 36 (76.6%) cases, whereas minimal endoleak was observed in 11 cases. Four patients had procedure-related complications, including 1 patient with acute in-stent thrombosis, 2 with a post-operative subarachnoid haemorrhage, and 1 with artery rupture. Angiographic and clinical follow-up was available for 36 patients (38 aneurysms). Complete aneurysm occlusion was achieved in 34 (89.5%) cases, endoleak was present in 2 cases, and aneurysm recurrence occurred in 2 cases. Asymptomatic in-stent stenosis was observed in 3 patients. No hemorrhagic or ischemic events occurred during the follow-up period. At follow-up, the modified Rankin scores were 0–2 for 35 patients and >2 for 1 patient. Satisfactory angiographic outcomes were achieved in our study. However, the risks of stent navigation failure, endoleak after balloon re-inflation, procedure-related complications and coverage of side branches should be considered when choosing the best therapeutic option for internal carotid artery aneurysms. [ABSTRACT FROM AUTHOR]

The Willis covered stent (WCS) may prolapse into the aneurysmal sac due to device migration or foreshortening. We present a useful salvage strategy that can reorient a prolapsed WCS into a more suitable alignment. An intra-procedural prolapse of a WCS into a large cavernous aneurysm occurred in a 70-year-old female patient. A pipeline embolization device (PED) was used to retrieve the WCS and successfully accomplish flow diversion. Maintaining proximal access and ensuring that the microwire is securely held within the central axis of the herniated stent are critical until the entire parent vessel can be reconstructed. This salvage technique may help to regain proximal access and reposition the flow diversion constructs following WCS prolapse.

Treatment of selective intracranial aneurysms treated with a Willis covered stent is safe and effective. We describe a previously unreported case of a large, irregular, carotid-ophthalmic aneurysm that was treated with a Willis covered stent. An immediate angiogram after the procedure showed complete occlusion of the aneurysm. However, a six-month follow-up angiogram demonstrated contrast media filling of the aneurysm neck. To the best of our knowledge, this is the first report of a recurrent aneurysm treated with a Willis covered stent because of a membrane partially isolated with the stent. This case suggests that an aneurysm that is treated with a Willis covered stent might recanalise, and the risk of aneurysm rupture persists when the membrane of the stent is isolated with the stent. Therefore, follow-up angiography is necessary, even if an immediate angiogram shows complete aneurysm occlusion. Long-term follow-up is required, and the final outcome of such a case is still unknown. [ABSTRACT FROM AUTHOR]

The Willis covered stent (WCS) may prolapse into the aneurysmal sac due to device migration or foreshortening. We present a useful salvage strategy that can reorient a prolapsed WCS into a more suitable alignment. An intra-procedural prolapse of a WCS into a large cavernous aneurysm occurred in a 70-year-old female patient. A pipeline embolization device (PED) was used to retrieve the WCS and successfully accomplish flow diversion. Maintaining proximal access and ensuring that the microwire is securely held within the central axis of the herniated stent are critical until the entire parent vessel can be reconstructed. This salvage technique may help to regain proximal access and reposition the flow diversion constructs following WCS prolapse. [ABSTRACT FROM AUTHOR]

We report a case of late type IIIb endoleak with Willis covered stent (WCS) developed 14 months after endovascular paraclinoid aneurysm repair. A 52-year-old woman presented with episodic headache, caused by a giant paraclinoid aneurysm. She underwent a successful 3.5 x 16mm WCS positioning to treat the aneurysm. Fourteen months later, the patient was admitted with the same symptoms. Digital subtraction angiography examination showed recurrence of the aneurysm, which was similar to the preoperative one. DynaCT (Siemens, Erlangen, Germany) indicated the intact of the metal structure of the stent without migration. Type IIIb endoleak (defect in the graft fabric) was confirmed with a whole aneurysm neck located in the middle part of the stent. The type IIIb endoleak was treated with another WCS (4.0 x 16mm). The immediate digital subtraction angiography imaging indicated that the endoleak disappeared and the aneurysm was completely occluded. Re-examination done 1 year after the second treatment showed a complete exclusion of the aneurysm sac. Type IIIb endoleaks can be safely treated by the endovascular positioning of another WCS. Continuous surveillance after endovascular paraclinoid aneurysm repair for intracranial aneurysms is warranted to make ensure the safety of WCS. [ABSTRACT FROM AUTHOR]

Objective: Preliminary studies suggest that Willis covered stents may be suitable for the treatment of aneurysms of the internal carotid artery (ICA), but their efficacy and safety in vertebral artery (VA) dissecting aneurysms need further investigation. Methods: Consecutive patients who underwent placement of a Willis covered stent for treatment of an aneurysm of the V4 segment of the VA between September 2015 and December 2017 at our institution were retrospectively reviewed. The efficacy, complications, angiographic and clinical follow-up results were collected and analyzed. Results: Sixteen covered stents were successfully implanted into the VA in 12 patients with 12 dissecting aneurysms. The technical success rate of stenting placement was 100%. Complete occlusion was achieved in 11 patients immediately after stent placement, with transient endoleak in one aneurysm. Angiographic follow-up (9.9 ± 4.0 months, mean±SD) was performed in nine patients and demonstrated complete stabilization of the obliterated aneurysm. Clinical follow-up (20.1 ± 9.6 months, mean±SD) demonstrated full recovery in 11 patients, and one patient suffered from acute myocardial infarction. Conclusion: Reconstruction using a Willis covered stent is an efficient, safe and attractive alternative for the definitive treatment of intracranial VA dissecting aneurysms; longer follow-up and expanded clinical trials are needed for further validation of this technique. [ABSTRACT FROM AUTHOR]

A 46-year-old male presented to our hospital suffering from right mastoid pulsatile tinnitus secondary to traffic trauma. Digital subtraction angiography was remarkable for a vertebro-vertebral arteriovenous fistula fed by the right vertebral artery at the C1 level. Dual platelet therapy was administrated before and after the operation, then a Willis covered stent was deployed at the orifice of the fistula. Post-operative angiography showed proper stent localization but some contrast agent leaking from the fistula. Angiography performed 6 months post-operatively demonstrated no leak from the fistula and the patency of the right vertebral artery. This case demonstrated that an intracranial covered stent could be used as an alternative, successful treatment for vertebro-vertebral arteriovenous fistula. [ABSTRACT FROM AUTHOR]

The use of Willis covered stent (WCS) for intracranial aneurysms has increased based on the promising results of previous studies about its safety and effectiveness. With the accumulation of cases, reports about peri-procedural complications are emerging. In our department, 25 patients were treated with WCS during December 2015 to March 2017. We here reported an unexpected technical complication occurred in the treatment with the WCS for a blood blister-like aneurysm (BBA). During the procedure, the distal end of the stents detached from the dilating balloon partially or as a whole. This was attributed to the tortuosity of the access route and the extracorporeal gas exhaust maneuver. Then we applied a half-dilating technique to retrieve the detached stent. The procedures were detailed in this report and the possible reasons and approaches to avoid it were explored.

Objective To evaluate the safety and efficacy of Willis covered stent implantation for treating complex vascular diseases in the distal internal carotid artery. Methods 14 patients with complex vascular diseases of the distal internal carotid arteries were treated with 15 Willis covered stents from July 2015 through January 2017. Clinical records including technical success, initial and final digital subtraction angiography (DSA)results, mortality, morbidity and clinical outcome within 3〜18months after treatment were retrospectively analyzed. Results The 14 vascular diseases of the distal internal carotid arteries included blood blister-like aneurysms (8), pseudoaneurysms (3), multiple aneurysms (1), and large wide-necked aneurysms (2). The release sites of Willis covered stents were C7 (3), C6 (8), C5 (2), and C4 (2) segments of the internal carotid arteries. The technical success rate was 100%. In 10 patients, angiography performed immediately after stent release showed complete disappearance of the aneurysm and the parent arteries remained patent. Endoleak was observed in 4 patients, which resolved completely (2) or partially with minor leak (1) after balloon dilatation. Another stent was implanted to eliminate the endoleak on the fourth patient. Occlusion of the ophthalmic artery (2) and anterior choroidal artery (1) occurred after stent implantation with no obvious neurologic symptoms. There were no significant procedural events during the perioperative period. No new neurological deficits were observed on follow-up with mRS score of 0 in 12 patients and 1in2 patients. Postoperative DSA showed patent(13) or mildly stenotic (1) parent arteries, completely occluded (13) or recurrent (1)aneurysms. Conclusion Willis covered stent implantation is safe and effective for treating complex vascular diseases in the distal internal carotid artery with good short and mid-term outcomes. [ABSTRACT FROM AUTHOR]

Internal carotid artery dissection (ICAD) is a major cause of ischemic stroke in young and middle-aged patients. Patients may be asymptomatic or present with symptoms ranging from headache and neck pain to severe cerebral ischemic events. Conventional treatment is medical anticlotting therapy or involves the use of interventional tools, such as endovascular treatment. Anticoagulation or antiplatelet therapy are the primary treatment modalities used to prevent thromboembolic complications from arterial dissections, however, they are unsuitable in certain cases of dissecting aneurysms. In the current study reports the case of a 52-year-old male patient presenting with the primary complaint of left limb weakness. Computed tomography angiography revealed a right ICAD located in the oropharyngeal segment. Subsequently, digital subtraction angiography was performed to assess the oropharyngeal segment. Antithrombotic therapy resulted in no improvement; therefore, endovascular treatment with the insertion of a Willis covered stent was performed, resulting in an improved outcome. [ABSTRACT FROM AUTHOR]

Background Despite the current availability of flow diverter devices (FDD), problems remains regarding optimal endovascular treatment (EVT) for blood blister-like aneurysms (BBAs) of the internal carotid artery (ICA). Objective To evaluate the safety and efficacy of EVT of BBAs in the ICA with a Willis covered stent. Methods 20 consecutive patients (5 men and 15 women) with ruptured BBAs underwent EVT using a Willis covered stent in two institutions from March 2013 to March 2018. Clinical observations, angiographic characteristics, and procedural and follow-up outcomes were retrospectively evaluated. Results 20 consecutive patients (5 men and 15 women) with ruptured BBAs underwent EVT using a Willis covered stent in two institutions from March 2013 to March 2018. Clinical observations, angiographic characteristics, and procedural and follow-up outcomes were retrospectively evaluated. Conclusion Our initial results demonstrate that reconstructive EVT using a Willis covered stent provides a viable approach to treat ICA BBAs. However, an expanded clinical evaluation and larger cohort are needed to confirm the results., (© 2018 Shanghai Journal of Interventional Medicine Press. Production and hosting by Elsevier B.V. on behalf of KeAi.)

Objective: The purpose of the present study was to introduce our initial experience with the use and feasibility of the Willis covered stent (WCS) in the treatment of blood blister-like aneurysms (BBAs) and to present a systematic review of the reported data on the treatment of BBAs with covered stents., Methods: Fourteen consecutive patients with BBAs had been treated with WCSs at West China Hospital from January 2015 to August 2017. The patient medical records, angiographic findings, and endovascular treatment reports were reviewed by interventional neuroradiologists and neurosurgeons to obtain relevant clinical and angiographic information. We conducted a systematic review of all reports of BBAs treated with covered stents. We searched the reported data using PubMed, Embase, China National Knowledge Infrastructure, and Wanfang databases and commercial Internet search engines. We included BBAs located at nonbranching portions of the internal carotid artery (ICA)., Results: The present study included 9 men and 5 women, with a mean age of 54.5 years (range, 30-79). All patients had complete occlusion found on immediate postoperative angiography. The ophthalmic artery was occluded in 2 patients (14.3%). No mortality or morbidity had occurred during the procedure. Two patients (14.3%) experienced a mild recurrence. One patient (7.1%) had developed mild in-stent stenosis. The clinical follow-up period was 6-15 months for all the patients. Of the 14 patients, 11 (78.6%) had a modified Rankin scale score of 0, and 1 (7.1%) had a modified Rankin scale score of 1 during the follow-up period. One patient (7.1%) experienced subarachnoid hemorrhage at 7 days postoperatively and had died 10 days after surgery. None of the patients experienced visual defects. Of our 14 patients, 13 (92.9%) survived, as determined by outpatient department visits or telephone interviews. A total of 8 reports, including 38 patients, met our criteria. Of these 38 patients, 37 (97.3%) had successful delivery to the diseased ICA, and 34 (89.5%) had experienced complete occlusion during follow-up. The overall rate of complete occlusion was 83.0% (95% confidence interval, 68%-91%)., Conclusions: Patients with ruptured BBAs treated with WCSs can achieve satisfactory clinical results. Therefore, for BBAs, the implementation of the WCS could be safe and feasible. This strategy could be a promising option for this type of high-risk aneurysm. However, patients with tortuous ICAs or aneurysms close to essential branch arteries should be carefully evaluated before the WCS is used., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objective: To report the clinical results and initial clinical experience of endovascular isolation with the Willis covered stent for carotid siphon aneurysms., Methods: Between November 2013 and December 2016, a total of 57 patients who presented with carotid siphon aneurysms were treated with the Willis covered stent. Results of the procedures, technical events, and complications were recorded. Clinical and imaging follow-ups were performed at 3 months following the endovascular procedures., Results: Placement of the Willis covered stent was successful in all patients. Immediate angiography revealed complete exclusion of aneurysms in 48 patients (84%), while endoleak occurred in nine patients (16%). Procedure-related complications occurred in three cases, including displacement of the covered stent in one patient, acute in-stent thrombosis in one patient, and microwire-related intracranial hemorrhage in one patient. Angiographic follow-ups were done in 49 patients, with complete exclusion of aneurysms in 47 patients. Endoleak was present in two patients. No aneurysm recurrence occurred. Forty-four patients showed good parent artery patency, while the other five patients showed mild to moderate asymptomatic in-stent stenosis. During the follow-up period, no ischemic or hemorrhagic event occurred. The modified Rankin Scale scores at follow-up were 0-2 in 56 patients and >2 in one patient., Conclusions: The treatment of siphon aneurysms with Willis covered stent implantation resulted in satisfactory clinical outcomes. The Willis covered stent seems safe and feasible for the treatment of siphon aneurysms, which still needs to be confirmed by longer follow-up periods and controlled studies with larger samples., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)