Concomitant coiling reduces metalloproteinase levels in flow diverter-treated aneurysms but anti-inflammatory treatment has no effect

Topographic distribution of inflammation factors in a healing aneurysm

BACKGROUND

Healing of intracranial aneurysms following endovascular treatment relies on the organization of early thrombus into mature scar tissue and neointima formation. Activation and deactivation of the inflammation cascade plays an important role in this process. In addition to timely evolution, its topographic distribution is hypothesized to be crucial for successful aneurysm healing.

METHODS

Decellularized saccular sidewall aneurysms were created in Lewis rats and coiled. At follow-up (after 3 days (n = 16); 7 days (n = 19); 21 days (n = 8)), aneurysms were harvested and assessed for healing status. In situ hybridization was performed for soluble inflammatory markers (IL6, MMP2, MMP9, TNF-α, FGF23, VEGF), and immunohistochemical analysis to visualize inflammatory cells (CD45, CD3, CD20, CD31, CD163, HLA-DR). These markers were specifically documented for five regions of interest: aneurysm neck, dome, neointima, thrombus, and adjacent vessel wall.

RESULTS

Coiled aneurysms showed enhanced patterns of thrombus organization and neointima formation, whereas those without treatment demonstrated heterogeneous patterns of thrombosis, thrombus recanalization, and aneurysm growth (p = 0.02). In coiled aneurysms, inflammation markers tended to accumulate inside the thrombus and in the neointima (p < 0.001). Endothelial cells accumulated directly in the neointima (p < 0.0001), and their presence was associated with complete aneurysm healing.

CONCLUSION

The presence of proinflammatory cells plays a crucial role in aneurysm remodeling after coiling. Whereas thrombus organization is hallmarked by a pronounced intra-thrombotic inflammatory reaction, neointima maturation is characterized by direct invasion of endothelial cells. Knowledge concerning topographic distribution of regenerative inflammatory processes may pave the way for future treatment modalities which enhance aneurysm healing after endovascular therapy.

Safety and Efficacy of Coils in Conjunction With the Pipeline Flex Embolization Device for the Treatment of Cerebral Aneurysms

Background: Flow diverters (FD) have shown promising results in the treatment of intracranial aneurysms (IAs). However, there is still controversy whether pipeline flex embolization device (PED flex)-assisted coils can facilitate the curing of aneurysms. Our aim was to assess the safety and effectiveness of PED flex adjunctive with coils (PED flex + coil) in the treatment of IAs. Method: Patients who underwent PED flex treatment in combination with coiling between January 2018 and June 2020 were included in this study. The clinical and radiographic characteristics before and after treatments were retrospectively evaluated. The study cohort comprised of 125 patients with 140 IAs, which was subdivided into two subgroups: one group included patients treated only through PED alone, and the other group included patients treated through PED flex adjunctive with coil. Patient baseline characteristics, aneurysm characteristics, treatment-related factors, and outcomes were analyzed to determine the effectiveness of both techniques. Results: Aneurysms in the PED flex + coil group were larger (10.0 ± 5.8 mm, P < 0.001) and wider (7.2 ± 4.6 mm, P = 0.002) compared with those in the PED flex group. There was no statistical difference in the perioperative complication rate between the two groups. The overall complete occlusion rate was 75.7% at 6.2 months, with 71.7% at 6.2 ± 1.7 months in the PED flex group and 85.4% at 6.2 ± 1.8 months in the PED flex + coil group, respectively. A higher percentage of satisfactory angiography results was found in the PED flex + coil group during follow-up (92.7 vs. 78.8%, P = 0.047). Conclusion: PED flex placement with adjunctive coil embolization represents a safe alternative option for the treatment of IAs. In these cases, coil embolization increases the occlusion rate in PED flex-treated patients without increasing the periprocedural complications.

Growth of unruptured aneurysms: A meta-analysis of natural history and endovascular studies

The growth of unruptured intracranial aneurysms (UIAs) is a strong predictor of rupture. Clinical observations suggest that some UIAs might grow faster after endovascular treatment than untreated UIAs. There are no head-to-head comparisons of incidence rates of UIAs thus far.

METHODS

We searched PubMed, Embase and Google Scholar for relevant articles from the inception of the databases to March 2020. We pooled and compared the incidence rates for the growth of aneurysms from natural history studies and endovascular treatment studies. Generalized linear models were used for confounder adjustment for the prespecified confounders age, size and location.

RESULTS

Twenty-five studies (10 describing growth in natural history and 15 reporting growth after endovascular therapy) considering 6325 aneurysms were included in the meta-analysis. The median size of aneurysms was 3.7 mm in the natural history studies and 6.4 mm in endovascular treatment studies (p = 0.001). The pooled incidence rate (IR) of growth was significantly higher in endovascular treatment studies (IR 52 per 1000 person-years, with a 95% confidence interval (CI) 36-79) compared to natural history studies (IR 28 per 1000 person-years, 95% CI 17 - 46, p-value < 0.01) after adjustment for confounders.

CONCLUSION

Our results suggest that the incidence rate of cerebral aneurysm growth might be higher after endovascular therapy than the incidence rates reported in natural history studies. These results should be viewed in light of the risk of bias of the individual studies and the risk of ecological bias.

Construction of biological factor-coated stent and its effect on promoting endothelialization

Recently, just taking endothelialization of stent as an interventional treatment of aneurysms is unsatisfactory. This treatment also has impacts the occlusion rate of the aneurysm. In accordance with that, the authors aims to construct a novel biological factor-coated stent with dual biological effects of anticoagulation and endothelialization for the improvement of the occlusion rate of aneurysms and reduction of the risk for treatment of aneurysm with intravascular interventional therapy. The Ni-Ti alloy sheets loaded with VEGF and anti-CD34 antibody were put into use for stimulating the construction of the biological factor-coated stents, for the Ni-Ti alloy sheets could help improve the proliferation of endothelial cell (EC), recognize effectively and adhere to endothelial progenitor cell (EPC). Blood compatibility characterization methods (water contact angle, platelet activation test, clotting time evaluation and protein adsorption test) were applied for study the influence of the interaction between the Ni-Ti alloy sheets and blood. Cell experiments (HUVEC proliferation experiment, migration experiment and EPC capture experiment) were resorted to investigate the ability of the sheets to promote the proliferation of HUVEC and to capture EPCs. With the mature of the construction technology, the Enterprise stent with the biological factors were optimized accordingly, the biological function of that were verified by cell experiments. Studies showed that Ni-Ti alloy sheets and enterprise stents can successfully load with VEGF and anti-CD34 antibody. The below achievements can be realized including a better blood compatibility and effects of the constructed sheets and enterprise stents on promoting HUVEC proliferation and adhesion of EPC. It was meaningful of conversion to clinical application to improve the cure rate of the aneurysm and the safety of the intravascular treatment.

The p48_HPC antithrombogenic flow diverter: initial human experience using single antiplatelet therapy

Objective

The p48 is a low-profile, intermediate-porosity flow diverter. phenox GmbH-trademarked hydrophilic polymer coating (pHPC) is a hydrophilic coating that has been shown in vitro to reduce the thrombogenicity of nitinol device surfaces. We performed the present study to determine whether the p48_HPC can be implanted using prasugrel alone.

Methods

We retrospectively identified all patients who were treated with the p48_HPC from January 2017 to December 2018 (n = 5) and underwent single antiplatelet therapy (SAPT) with prasugrel. P2Y12 inhibition was confirmed by the VerifyNow assay. The occurrence of thromboembolic and haemorrhagic complications was recorded alongside the occlusion rates of the treated aneurysms.

Results

All patients achieved adequate occlusion (Raymond–Roy Occlusion Classification I or II) during the follow-up period. No thromboembolic complications occurred. One patient developed a contained haematoma within the Sylvian fissure from the treated aneurysm 2 weeks postoperatively without clinical sequelae.

Conclusions

In this small series, no thromboembolic complications occurred in patients treated with the surface modified p48_HPC flow diverter and SAPT. Further studies with longer follow-up periods and larger cohorts should be performed.

Large Basilar Apex Aneurysms Treated with Flow-Diverter Stents

BACKGROUND AND PURPOSE

The treatment of wide-neck, large basilar apex aneurysms is challenging with either an endovascular or a surgical approach. The aim of the present study was to report our experience treating basilar apex aneurysms with flow-diverter stents and to evaluate their efficacy and safety profile in this specific anatomic condition.

MATERIALS AND METHODS

We retrospectively analyzed data from all consecutive patients treated with flow-diverter stents at our institution between January 2011 and January 2015. Patients with large basilar apex aneurysms treated with a flow-diverter stent were included in the study. Clinical presentations, technical details, intra- and perioperative complications, and clinical and angiographic outcomes were recorded, with a midterm follow-up.

RESULTS

Of the 175 aneurysms treated with flow-diverter stents at our institution, 5 patients (2 women and 3 men; age range, 44-58 years) received flow-diverter stent for basilar apex aneurysms. The mean follow-up after stent deployment was 21 months (range, 15-24 months). One patient died on day 31 from an early postprocedural midbrain hemorrhage. One patient had a right cerebellar hemispheric ischemic lesion with a transient cerebellar syndrome resolved within 24 hours without neurologic sequelae at the latest follow-up. The mRS was 0 in 4 patients and 6 in 1 patient at last follow-up.

CONCLUSIONS

Flow diversion is a feasible technique with an efficacy demonstrated at a midterm follow-up, especially in the case of basilar apex aneurysm recurrences after previous endovascular treatments. Concern about its safety profile still exists.

Treatment of Intra- and Extracranial Aneurysms Using the Flow-Redirection Endoluminal Device: Multicenter Experience and Follow-Up Results

BACKGROUND AND PURPOSE

Flow diversion emerged as a crucial treatment option for intracranial aneurysms. We report a multicenter retrospective analysis of the safety and efficacy in the treatment of intracranial aneurysms with the Flow-Redirection Endoluminal Device (FRED) flow diverter, a dual-layer flow-modulation device.

MATERIALS AND METHODS

All intracranial aneurysms treated with the FRED between March 2013 and February 2016 at 4 neurovascular centers were included. Angiographic and clinical results were retrospectively analyzed, including all follow-up examinations. Aneurysms were unruptured in 44 cases, whereas 8 treatments were due to an acute SAH from the target aneurysm.

RESULTS

Successful implantation of the FRED was possible in 96.2% (50/52) of cases. At 3-month follow-up, complete occlusion was determined in 58.1% (25/43) and near-complete in 25.6% (11/43). At 12-month follow-up, aneurysm occlusion was complete in 75.0% (27/36) and near-complete in 22.2% (8/36). The overall acute and late thromboembolic and hemorrhagic complication rate was 17.3% (9/52), with a permanent treatment-related morbidity and mortality of 4.0% (2/50) and 2.0% (1/50), respectively, to date.

CONCLUSIONS

The FRED device offers an effective tool in the treatment of intracranial aneurysms. The dual-layer design promotes contemporary and stable long-term occlusion rates. Sufficient device expansion should be documented by angiographic CT. Further studies might help to identify a more optimal antiplatelet regimen to avoid thromboembolic complications during the follow-up period.