Longitudinal Monitoring of Flow-Diverting Stent Tissue Coverage After Implant in a Bifurcation Model Using Neurovascular High-Frequency Optical Coherence Tomography

The DERIVO 2 Heal Embolization Device in the Treatment of Ruptured and Unruptured Intracranial Aneurysms: a Retrospective Multicenter Study

BACKROUND

The use of flow diverting stents in the treatment of intracranial aneurysms is associated with a risk of neurological morbidity due to their thrombogenicity. To reduce this risk different surface modifications have been developed. The Derivo 2 Embolization Device (Acandis, Pforzheim, Germany) has proven to be a safe and effective flow diverter. To overcome the risk of thrombo-embolism, the device was modified by adding an anti-thrombogenic fibrin-heparin coating. We aimed to assess the safety and effectiveness of the Derivo 2 heal Embolization Device.

METHODS

Retrospective multicenter data from nine German neurovascular centers between February 2022 until December 2023 were used. Patients treated with the Derivo 2 heal Embolization Device for unruptured or ruptured intracranial aneurysms were included. Peri- and postprocedural adverse events, clinical outcomes, and angiographic follow-up results were evaluated.

RESULTS

84 patients (73.8% female; mean age 58.7 years) with 89 aneurysms (mean size 9.8 mm) were included. 87.6% were located in the anterior circulation. Most of them were sidewall aneurysms (88.8%). 96 flow diverters were used. 99.0% were successfully implanted. An in-stent balloon angioplasty was performed in 6.0% of the cases. An additional coiling was performed in 28.6%. Technical difficulties were present in 12.0% of the cases. Thrombotic events occurred in 4.8% with no neurological sequelae. Mortality and morbidity were 0 and 1.2% respectively. Adequate aneurysm occlusion was achieved in 80.7% with a mean follow-up time of 6.6 months.

CONCLUSION

The Derivo 2 heal Embolization Device showed a satisfying aneurysm occlusion and safety with a low rate of neurological morbidity.

Neqstent coil-assisted flow diverter (NQS) for the treatment of bifurcation aneurysms: the coil-assisted flow diversion safety and performance study (CAFI)

BackgroundThe Neqstent coil-assisted flow diverter (NQS) is a neck bridging device to facilitate coil occlusion of intracranial aneurysms. CAFI is a prospective, single-arm, multicenter study on the safety and performance of the NQS adjunctive therapy device together with platinum coils for treatment of unruptured intracranial aneurysms.

METHODS

Thirty-eight patients were enrolled. Primary endpoints were occlusion at 6 months for efficacy, and any major stroke or non-accidental death up to 30 days or major disabling stroke within 6 months for safety. Secondary endpoints were re-treatment rate, procedure time, and procedure/device-related adverse events. Procedural and follow-up imaging was reviewed by an independent core laboratory. Adverse events were reviewed and adjudicated by a clinical events committee.

RESULTS

The NQS was successfully implanted in 36/38 aneurysms, 2/38 in the intention-to-treat group did not receive a NQS and were excluded from follow-up after 30 days. In the per protocol group (PP), 33/36 patients were available for angiographic follow-up. Device related adverse events were recorded in 4/38 (10.5%) patients, one hemorrhagic and three thromboembolic. In the PP group, immediate post-treatment adequate occlusion (RR1 and RR2) was seen in 9/36 (25%) and progressed to 28/36 (77.8%) at 6 months. Complete occlusion (RR1) was achieved in 29/36 (80.6%) at the last available angiogram (3/36 were post procedure). The mean procedure time was 129 min (50-300 min, median 120 min).

CONCLUSION

The NQS in conjunction with coils appears to be effective in the treatment of intracranial wide-neck bifurcation aneurysms, but its safety remains to be proved in larger series.

TRIAL REGISTRATION NUMBER

NCT04187573.

Management of aneurysmal recurrence after Woven EndoBridge (WEB) treatment

BACKGROUND

Around 10% of Woven EndoBridge device (WEB)-treated intracranial aneurysms will need retreatment, and it is generally believed to be more challenging than retreatment after an initial coiling. We aim to report retreatment strategies and outcomes after initial WEB embolizations.

METHODS

Databases from four treatment centers, containing consecutive aneurysms treated with a WEB between 2013 and 2022, were reviewed. Demographics, aneurysm characteristics, retreatment strategies and outcomes were collected and analyzed.

RESULTS

From a 756 WEB database, 57 aneurysms were included. The global retreatment rate was 7.5% (95% CI 5.6% to 9.4%). The retreatment rate was significantly higher in the ruptured compared with the unruptured population (13% vs 3.9%, respectively, P<0.0001). Aneurysms were retreated on average 21.2 months after the initial WEB treatment (range 4.8-70 months). Surgery was performed in 11% and endovascular treatment in 89% of cases, consisting of flow diversion (48%), stent-assisted coiling (30%), coiling (12%), and second WEB placement (10%). Imaging follow-up was available in 88% of all WEB retreatments (50/57) (average 17 months, 49% digital subtraction angiography), demonstrating complete occlusion in 56% and 'adequate' occlusion in 88%. Morbidity was 5.3% (95% CI 0% to 12.0%) and mortality 0%. No patient experienced rebleeding during the follow-up period.

CONCLUSION

The retreatment rate after an initial WEB treatment seems to compare favorably with that of coiling. Endovascular treatment of recurrence following WEB implantation is feasible in most situations; it generally requires the use of a stent and leads to a high rate of satisfactory occlusion.

High-frequency optical coherence tomography predictors of aneurysm occlusion following flow diverter treatment in a preclinical model

BACKGROUND

High-frequency optical coherence tomography (HF-OCT) is an intravascular imaging method that allows for volumetric imaging of flow diverters in vivo.

OBJECTIVE

To examine the hypothesis that a threshold for both volume and area of communicating malapposition can be predictive of early aneurysm occlusion.

METHODS

Fifty-two rabbits underwent elastase aneurysm formation, followed by treatment with a flow diverter. At the time of implant, HF-OCT was acquired to study the rate and degree of communicating malapposition. Treated aneurysms were allowed to heal for either 90 or 180 days and euthanized following catheter angiography. Healing was dichotomized into aneurysm remnant or neck remnant/complete occlusion. Communicating malapposition was measured by HF-OCT using a semi-automatic algorithm able to detect any points where the flow diverter was more than 50 µm from the vessel wall. This was then summed across image slices to either a volume or area. Finally, a subsampled population was used to train a statistical classifier for the larger dataset.

RESULTS

No difference in occlusion rate was found between device type or follow-up time (p=0.28 and p=0.67, respectively). Both volume and area of malapposition were significantly lower in aneurysms with a good outcome (p<0.001, both). From the statistical model, a volume of less than 0.56 mm3 or a normalized area less than 0.69 as quantified by HF-OCT was predictive of occlusion (p<0.001, each).

CONCLUSIONS

HF-OCT allows for measurements of both volume and area of malapposition and, from these measurements, an accurate prediction for early aneurysm occlusion can be made.

Persistent Opacification of the Woven EndoBridge Device: A Conebeam CT Analysis of the Bicêtre Occlusion Scale Score 1 Phenomenon

BACKGROUND AND PURPOSE

Some Woven EndoBridge devices present a persistent intradevice opacification at imaging follow-up, described as the Bicêtre Occlusion Scale Score 1 (BOSS 1) phenomenon. The clinical implications remain unknown. We aimed here to analyze the factors influencing this occurrence and to precisely describe the evolution of BOSS 1 with time using conebeam CT.

MATERIALS AND METHODS

We retrospectively analyzed a prospectively maintained Woven EndoBridge database at our tertiary center and included all patients with isolated BOSS 1 and BOSS 1 associated with small neck remnant (BOSS 1 + 2).

RESULTS

Two hundred sixty-seven aneurysms were treated with a Woven EndoBridge device between July 2012 and December 2021. Follow-up with DSA was available for 220 aneurysms (median, 5 months), among which BOSS 1 and 1 + 2 were found in 9.1% (20/220) (95% CI, 5.5%-12.7%). A second DSA follow-up (median, 17 months) was performed in 15 of these 20 aneurysms, which revealed that 40% had evolved to complete Woven EndoBridge occlusion, 33% showed a decreased persistent opacification, and 27% remained stable. BOSS 1 was significantly associated with postoperative antiplatelet medication, a lower aneurysm aspect ratio, and the use of the Woven EndoBridge 17 (P  < .05). The average Woven EndoBridge shape modification was less pronounced in the BOSS 1 population (P  < .02). None of the BOSS 1 or 1 + 2 aneurysms required retreatment or were associated with hemorrhage occurrence.

CONCLUSIONS

Isolated persistent flow inside the Woven EndoBridge device at follow-up is rare and notably associated with antiplatelet prescription. It seems to present a benign course in most cases.

The Safety and Effectiveness of the Contour Neurovascular System (Contour) for the Treatment of Bifurcation Aneurysms: The CERUS Study

BACKGROUND

The Contour is a novel intra-aneurysmal flow disrupting device to treat intracranial aneurysms.

OBJECTIVE

To evaluate the safety and effectiveness of the Contour device for treatment of nonruptured intracranial bifurcation aneurysms through a prospective, multicenter, single-arm study.

METHODS

Thirty-four patients were enrolled. Primary end points were successful occlusion at 6 mo for efficacy and any major stroke or nonaccidental death up to 30 d or major disabling stroke within 6 mo for safety. Secondary end points were occlusion at 12 mo, retreatment rate, procedure time, and procedure-related/device-related adverse events. Procedural and follow-up imaging was reviewed by an independent core laboratory. Adverse events were reviewed and adjudicated by a clinical events committee.

RESULTS

In total, 32 of 34 aneurysms were successfully implanted and, 2 of 34 in the intention-to-treat (ITT) group did not receive the Contour and were excluded from follow-up after 30 d. In addition, 2 of 32 were lost to angiographic follow-up and regarded as treatment failure. The primary safety end point was met in 2 patients in the ITT group. In the perprotocol (PP) group, complete occlusion was seen in 14 of 32 (44%) at 6 mo and 22 of 32 (69%) at 12 mo. Adequate occlusion (Raymond-Roy [RR] 1 and 2) was reached in 84% at a last available follow-up. One patient from the ITT group and 1 from the PP group received additional treatment during follow-up.

CONCLUSION

The Contour seems to be both safe and effective in the treatment of intracranial bifurcation aneurysms.

Optical Coherence Tomography for Neurovascular Disorders

Diagnosis of cerebrovascular disease includes vascular neuroimaging techniques such as computed tomography (CT) angiography, magnetic resonance (MR) angiography (with or without use of contrast agents) and catheter digital subtraction angiography (DSA). These techniques provide mostly information about the vessel lumen. Vessel wall imaging with MR seeks to characterize cerebrovascular pathology, but with resolution that is often insufficient for small lesions. Intravascular imaging techniques such as ultrasound and optical coherence tomography (OCT), used for over a decade in the peripheral circulation, is not amendable to routine deployment in the intracranial circulation due to vessel caliber and tortuosity. However, advances in OCT technology including the probe profile, stiffness and unique distal rotation solution, holds the promise for eventual translation of OCT into the clinical arena. As such, it is apropos to review this technology and present the rationale for utilization of OCT in the cerebrovasculature.