Application of the Willis covered stent in the treatment of internal carotid artery blood blister-like aneurysms

Endovascular treatment of intracranial blood blister-like aneurysms with the Willis covered stent: a case series

BACKGROUND AND PURPOSE

To evaluate the safety, feasibility, and effectiveness of the Willis covered stent (WCS) in treating blood blister-like aneurysms (BBAs).

MATERIALS AND METHODS

Twenty-one consecutive patients with BBAs treated with the WCS were identified between July 2017 and July 2022. The demographic, clinical, and angiographic data and procedural-related complications were collected from the medical records and the operative reports.

RESULTS

The present study included six men and fifteen women, with a mean age of 51.6 years (31-70 years). The immediate postoperative angiography demonstrated that the complete occlusion rate was 100%, with no endoleak. Ophthalmic artery (OA) occlusion occurred in five patients (23.8%). One patient developed delayed stent thrombosis on the third postoperative day. The mean angiographic follow-up time was 9.2 months (range 3-21 months). All twenty-one BBAs were occluded entirely, and the patency of the parent arteries was preserved. No aneurysm rupture or recurrence was found, and no retreatment was needed. Two patients developed mild to moderate asymptomatic in-stent stenosis. The clinical follow-up time was 20.0 months (range 15-33 months). Twenty patients had an mRS score of zero, and one had an mRS score of one.

CONCLUSIONS

Our series indicates that treating BBAs with WCSs was relatively safe and efficacious. However, the incidence of stent delivery failure and complications should not be neglected.

Comparison of a covered stent and pipeline embolization device in intracranial aneurysm: a propensity score matching analysis

BACKGROUND

The Willis covered stent (WCS) and pipeline embolization device (PED) have partly overlapping therapeutic indications. However, the differences of effect between these two treatments remain unclear.

OBJECTIVE

To compare clinical outcome, angiographic outcome, and complications following treatment with a WCS versus PED.

METHODS

Patients with intracranial aneurysms treated by a WCS or PED between January 2015 and December 2020 were included. The primary outcomes were complications, clinical outcome (modified Rankin Scale score >2), and angiographic outcome (incomplete aneurysm occlusion). Propensity score matching was conducted to adjust for potential confounding factors.

RESULTS

A total of 94 aneurysms treated by WCS and 698 aneurysms by PED were included. Compared with the PED group, patients in the WCS group are younger, a greater number have a poor condition at admission, a larger proportion of ruptured, non-saccular, and anterior circulation aneurysms, a smaller aneurysm neck width, and less coiling assistance is required. A total of 42 (44.7%) branches were covered by WCS. After adjustment for age, sex, aneurysm type, rupture status, neck size, aneurysm location, and coiling, 50 WCS and PED pairs were examined for internal carotid artery aneurysms. No significant differences were observed in clinical (10.4% vs 2.1%, P=0.206) and angiographic outcomes (12.8% vs 18.2%, P=0.713). However, 27 branches covered by WCS, including 22 ophthalmic arteries and five posterior communicating arteries. Patients in the WCS group had a higher intraoperative complication rate than those in the PED group (28% vs 6%, P=0.008), especially in the occlusion rate of covered branches (51.9% vs 11.1%, P<0.001).

CONCLUSION

The comparable clinical and angiographic outcomes of WCS or PED demonstrate the therapeutic potential of WCS as a viable alternative for aneurysms. However, the complication of occlusion of covered branches might not be negligible.

Impact of Stent Size Selection and Vessel Evaluation on Skull Base Cerebrovascular Diseases Treated With Willis Covered Stents: A Multicenter Retrospective Analysis

PURPOSE

This study aimed to evaluate the impact of the diverse stent size selection on the clinical and angiographic outcomes of Willis covered stent (WCS) for the treatment of skull base cerebrovascular diseases.

MATERIALS AND METHODS

A total of 147 patients with 151 skull base cerebrovascular diseases treated with WCS in 3 centers between January 2015 and July 2022 were included in this study. Several parameters depicting stent size and parent artery condition were incorporated into the analysis of the outcomes.

RESULTS

Complete occlusion was found in 106 cases (68.2%) immediately after deployment and 126 cases (83.4%) after technical adjustment. In the multivariate logistics analysis, the difference between stent diameter and parent artery diameter (DD) was significantly associated with immediate endoleak without adjustment (odds ratio [OR]=0.410; p=0.005) and late endoleak (OR=0.275; p=0.028). In addition, differences between stent diameter and parent artery diameter at wide landing point (DSW) and differences between stent diameter and parent artery diameter at narrow landing point (DSN) was also was significant associated with immediate endoleak without adjustment and balloon re-dilation respectively.

CONCLUSIONS

This study demonstrated that the diameter selection of the WCS was associated with the occurrence of endoleak during the treatment of skull base cerebrovascular diseases. Precise selection and evaluation of stent size and vessel condition were significant factors for skull base cerebrovascular diseases treated by WCS.

CLINICAL IMPACT

This study demonstrates a significant association between the diameter selection of the Willis covered stent (WCS) and the occurrence of endoleak in the management of skull base cerebrovascular diseases. The results offer valuable medical evidence that can inform stent selection for WCS. The study emphasizes the significance of precise evaluation of stent size and vessel condition as crucial factors in WCS procedures. These findings underscore the importance of meticulous consideration and individualized approaches to stent selection, ultimately improving treatment outcomes in clinical practice.

Willis covered stent treatment for blood blister-like aneurysm: A meta-analysis of efficacy and safety

Background

Blood blister-like aneurysm (BBA) is a rare and special type of intracranial aneurysm with extremely high rates of rupture, morbidity, mortality, and recurrence. Willis Covered Stent (WCS) is a new device that is specifically designed for the treatment of intracranial complex aneurysms. However, the efficacy and safety of WCS treatment for BBA remain controversial. Thus, a high level of evidence is required to prove the efficacy and safety of WCS treatment.

Methods

A systematic literature review was performed using a comprehensive literary search in Medline, Embase, and Web of Science databases to identify studies related to WCS treatment for BBA. A meta-analysis was then conducted to incorporate the efficacy and safety outcomes, including intraoperative situation, post-operative situation, and follow-up data.

Results

Eight non-comparative studies containing 104 patients with 106 BBAs met the inclusion criteria. In the intraoperative situation, the technical success rate was 99.5% [95% confidence interval (CI), 0.958, 1.000], the complete occlusion rate was 98.2% (95% CI, 0.925, 1.000), and the side branch occlusion rate was 4.1% (95% CI, 0.001, 0.114). Vasospasm and dissection occurred in 9.2% (95% CI, 0.000, 0.261) and 0.1% (95% CI, 0.000, 0.032) of the patients, respectively. In the post-operative situation, the rebleed and mortality rates were 2.2% (95% CI, 0.000, 0.074) and 1.5% (95% CI, 0.000, 0.062), respectively. In the follow-up data, recurrence and parent artery stenosis occurred in 0.3% (95% CI, 0.000, 0.042) and 9.1% (95% CI, 0.032, 0.168) of the patients, respectively. Ultimately, 95.7% (95% CI, 0.889, 0.997) of the patients had a good outcome.

Conclusions

Willis Covered Stent could be effectively and safely applied for BBA treatment. The results provide a reference for clinical trials in the future. Well-designed prospective cohort studies must be conducted for verification.

Advantages of Extradural Anterior Clinoidectomy and Extradural Approach with Dural Incision for Blood Blister Aneurysm or Pseudoaneurysm in the Internal Carotid Artery: Two Case Reports

Blood blister aneurysms (BBAs) or pseudoaneurysms (PAs) in the internal carotid artery (ICA) have fragile necks; therefore, conventional neck clipping is difficult. The standard treatment for BBAs or PAs is trapping with high or low flow bypass. However, there is no consensus on whether or not anterior clinoidectomy should be performed together. Two patients with ruptured ICA PA (anterior protrusion) or BBA (posterior protrusion) were presented to our hospital. Complete trapping was safely performed for both types of aneurysms via extradural anterior clinoidectomy and the extradural approach with dural incision. The advantages of the procedure are 1) safe proximal clipping, 2) early identification of the ICA C3 portion, 3) minimized frontal lobe retraction, 4) optic canal opening to allow mobility of the optic nerve, and 5) dural ring incision to allow mobility of the ICA.

Retreatment with a flow diverter for recurrent blood blister-like aneurysms after embolization: A single-center case series

Background and purpose

Treatment of blood blister-like aneurysms (BBAs) has been a significant challenge mainly due to their high recurrence rate even after stent-assisted coiling (SAC) embolization. This study aims to evaluate the safety and efficacy of treating recurrent BBAs after SAC with a flow diverter (FD).

Methods

A retrospective series of patients with recurrent BBAs who underwent the retreatment with the FD from June 2018 to December 2021 was included to analyze perioperative safety and immediate postoperative and follow-up outcomes.

Results

The study enrolled 13 patients with recurrent BBAs previously treated with SAC. Within previous stents, an FD was deployed for retreatment, including eight Tubridge FDs and five PEDs. The time interval between initial treatment and FD implantation was 14–90 days. A total of 11 cases were treated with a single FD alone; two cases were treated with further endovascular coiling embolization, followed by FD implantation. The angiographic follow-up (6–12 months) was available in 12 patients, and all 12 recurrent BBAs were completely occluded. No perioperative complication was detected, and no rebleeding was found during the clinical follow-up (6–36 months).

Conclusion

The use of the FD to manage recurrent BBAs after SAC is technically feasible, safe, and effective. The key to the success of the procedure is to ensure that the FD stent is fully open and has good apposition with the previously implanted stent.

Application of the Willis Covered Stent in the Treatment of Blood Blister-Like Aneurysms: A Single-Center Experience

Objective

To evaluate the effectiveness of the Willis covered stent (WCS) in the treatment of ruptured blood blister-like aneurysms (BBAs) of the internal carotid artery (ICA).

Method

The clinical data of 16 patients consecutively treated with WCSs from December 2015 to January 2019 were retrospectively analyzed. Clinical data and angiographic findings were analyzed by two experienced neuroradiologists and neurosurgeons, including age, sex, Hunt and Hess (H&H) grade at admission, modified Rankin scale (mRS) score, aneurysm size, and location, the diameter of the patent artery in proximal and distal ends, stent size, rate of aneurysm occlusion, procedure-related complications, and follow-up.

Results

All the 16 patients (five males, 11 females) with ICA BBAs underwent WCS deployment successfully. The median age was 49 years (range, 29–72). All patients had complete aneurysm occlusion on immediate postoperative angiography. Anterior choroidal artery (AChA) was occluded in one patient accidentally while no obvious neurological dysfunction was observed. However, this patient underwent subarachnoid hemorrhage 1 day after the treatment; endoleak and aneurysm recurred, and the patient died 10 days later. Therefore, the effective rate of WCS treatment was 93.8% (15/16), and procedure-related complications rate was 6.3% (1/16). Moreover, one patient was urgently treated because of accidental aneurysm rupture after anesthesia, and external ventricular drainage was then performed postoperatively. Another patient developed coma and hemiplegia 3 days after treatment, with emergency angiography showing in-stent thrombosis and ICA occlusion which was recanalized with arterial rt-PA thrombolysis; the patient recovered completely. The clinical follow-up period was 3–30 months in 14 patients. The mRS scores were 0 in 12 patients (85.7%) and 4 in 1 case (7.1%), while 1 patient (7.1%) died 6 months postoperatively for unknown reasons. Angiographic follow-up was performed in 13 patients, and no recurrence was observed. However, ICA occlusion without neurological deficit was observed in one patient.

Conclusion

Based on careful preoperative evaluation, appropriate WCS size selection, and precise surgical operation, WCSs may provide an alternative and effective solution for blood BBAs via aneurysm isolation and ICA reconstruction immediately; However, further follow-up studies with larger samples are required.