Timing, type, and impact of thromboembolic events caused by flow diversion: a 10-year experience.

OBJECTIVE: Thromboembolic (TE) events are among the most feared complications after flow diversion (FD) and have been reported to occur even with adequate dual antiplatelet therapy. Herein, the authors characterize thrombotic and embolic events that developed after FD, focusing on the morbidity of each of these events and the predisposing factors associated with their development. METHODS: A retrospective analysis of aneurysms treated with FD at a single institution in the US between 2013 and 2023 was performed. The authors documented the emergence of intraprocedural and postoperative TE events. A survival analysis and a Cox regression model was conducted to identify predictors associated with these events. RESULTS: The authors included 651 procedures performed in 591 patients to treat 746 aneurysms. TE events occurred in 38 of the procedures performed (5.8%), causing permanent deficit in 20 patients and death in 4 patients. Eleven cases presented with acute stent thrombosis, 11 with large-vessel occlusion, and 9 with perforator strokes. At a median follow-up of 9.5 months, 73.0% of patients with an ischemic event had a modified Rankin Scale score ≤ 2. Three of the deaths were secondary to occlusion at the basilar trunk and vertebral artery. In patients with TE events in the anterior circulation, 7 of 11 patients with middle cerebral artery occlusion and 9 of 12 patients with internal carotid artery occlusion achieved independence. Time-to-event Cox regression analysis demonstrated that TE events were more frequent in patients exhibiting aspirin resistance (hazard ratio 2.66; 95% CI 1.10-6.70). CONCLUSIONS: TE events after FD result from multiple factors, including age, aneurysm characteristics, aneurysm location, antiplatelet resistance, and procedural factors. In our cohort, we found the highest morbidity for patients with TE events presenting with large-vessel occlusion at the middle cerebral artery, and vertebrobasilar system.

Anterior choroidal artery aneurysms: a systematic review and meta-analysis of outcomes and ischemic complications following surgical and endovascular treatment.

OBJECTIVE: Anterior choroidal artery (AChA) aneurysms account for 2%-5% of all intracranial aneurysms. Treatment considerations include microsurgical clipping, flow diversion, or coiling with or without adjunctive devices. AChA aneurysms pose challenges in treatment due to the origination of the aneurysm from the origin or proximal segment of the AChA. The AChA is particularly susceptible to vasospasm and occlusion during treatment with devastating neurological deficits, including hemiparesis, hemianesthesia, lethargy, neglect, and hemianopia. In this study, the authors performed a meta-analysis to quantify the outcomes and complication rates across treatment modalities for AChA aneurysms and to identify risk factors reported in the literature. METHODS: The authors performed a systematic review of AChA aneurysms treated with surgical clipping, endovascular coiling, or flow diversion and reported in the PubMed, Embase, Scopus, and Cochrane search databases. Single-arm meta-analyses of the selected outcomes were performed in RStudio. RESULTS: Literature review yielded 25 studies that met the inclusion criteria. In total, 1627 patients were included in the analysis, with 554 males, 1009 females, and 64 unspecified. The rate of any complication in the full cohort was 11.6%, with a rate of ischemic complications of 5.5% and a favorable recovery rate of 90.3% of all patients treated. In total, 1064 patients underwent surgical clipping, 443 were treated with coiling, and 120 patients with flow diversion. In clipped patients, the rate of total surgical complications was 17.6%, with an ischemic complication rate of 9.4%. The rate of good functional recovery, defined on the basis of a Glasgow Outcome Scale score of 4-5 or modified Rankin Scale score of 0-2, was 88.0%, and complete obliteration was achieved in 84.5% of surgically clipped aneurysms. The complication rate in coiled patients was 10.3%, with an ischemic complication rate of 3.0%. Good functional recovery was achieved in 88.6% of coiled patients and complete aneurysm obliteration in 74.1%. Flow diversion resulted in a complication rate of 1.3%, with 0.7% rate of ischemic complications. Good functional recovery was achieved in 98.4% of patients and complete aneurysm obliteration in 79.0% in the flow diversion group. Aneurysm morphological features that impacted the complication rate were also identified to augment quantitative data and to help guide treatment selection for AChA aneurysms. CONCLUSIONS: Flow diversion showed significantly lower total and ischemic complications and improved outcomes compared to clipping and coiling. There may be differences in outcomes between treatment types, especially when considering the varied patient presentations that guide treatment selection.

Flow diversion of cerebral aneurysms in Type I osteogenesis imperfecta: A case report of the first two treatments in humans.

Osteogenesis imperfecta (OI) predisposes individuals to easy bone fracture, vessel fragility, and platelet dysfunction. We report the first known case of neurointerventional treatment with flow diversion of intracranial aneurysms in a patient with OI. A 62 year-old female with known OI Type I, history of >40 lifetime bone fractures and hypertension, underwent workup for transient ischemic attacks revealing a 4-mm right A1 segment aneurysm in 2016. Perioperative dual antiplatelet therapy was aspirin 81 mg and clopidogrel 37.5 mg daily. Tri-axial access was utilized to deploy a 3.5 × 16-mm Pipeline Flex device without complication. Two-month follow-up revealed Raymond I (O'Kelly Marotta I) obliteration of the aneurysm. Five-year follow-up revealed a de novo left-sided 3-mm A1-A2 junction aneurysm. A 4 × 12-mm Surpass Evolve was placed without complication. Six-month follow-up revealed Raymond I (O'Kelly Marotta I) obliteration of the second aneurysm. The patient remained asymptomatic at all follow-up visits.

Cost-effectiveness of platelet function testing in dual antiplatelet therapy decision-making after intracranial aneurysm treatment with flow diversion.

Dual antiplatelet therapy (DAPT) use is the standard of practice after flow diversion (FD) for intracranial aneurysms (IAs). Yet, no consensus exists in the literature regarding the optimal regimen. Certain institutions utilize various platelet function testing (PFT) to assess patient responsiveness to DAPT. Clopidogrel is the most commonly prescribed drug during DAPT; however, up to 52% of patients can be non-responders, justifying PFT use. Additionally, prices vary significantly among antiplatelet drugs, often further complicated by insurance restrictions. We aimed to determine the most cost-effective strategy for deciding DAPT regimens for patients after IA treatment. A decision tree with Monte Carlo simulations was performed to simulate patients undergoing various three-month postoperative DAPT regimens. Patients were either universally administered aspirin alongside clopidogrel, ticagrelor, or prasugrel without PFT, or administered one of the former thienopyridine medications based on platelet reactivity unit (PRU) results after clopidogrel. Input data for the model were extracted from the current literature, and the willingness-to-pay threshold (WTP) was defined as $100,000 per QALY as per standard practice in the US. The baseline comparison was with universal clopidogrel DAPT without any PFT. Probabilistic and deterministic sensitivity analyses were performed to evaluate the robustness of the model. Utilizing PFT and switching clopidogrel to prasugrel if resistance is documented was the most cost-effective regimen compared to universal clopidogrel, with a base-case incremental cost-effectiveness ratio (ICER) of $-35,255 (cost $2,336.67, effectiveness 0.85). Performing PFT and switching clopidogrel to ticagrelor (ICER $-4,671; cost $2,995.06, effectiveness 0.84), universal prasugrel (ICER $5,553; cost $3,097.30, effectiveness 0.84), or universal ticagrelor (ICER $75,969; cost $3,801.36, effectiveness 0.84) were all more cost-effective than treating patients with universal clopidogrel (cost $3,041.77, effectiveness 0.83). These conclusions remain robust in probabilistic and deterministic sensitivity analyses. The most cost-effective strategy guiding DAPT after FD for IAs is to perform PFTs and switch clopidogrel to prasugrel if resistance is documented, alongside aspirin. The cost of PFT is strongly justified and recommended when deciding patient-specific DAPT regimens.

Anatomical Flow Diversion by Hybrid Strategy for Intractable Large Cerebral Aneurysms.

BACKGROUND AND IMPORTANCE: Flow diverters (FDs) provide curative endovascular treatment for wide-necked sidewall aneurysms. The efficacy of FDs for bifurcation or branching sidewall aneurysms is probably limited. We used anatomical flow diversion (AFD) for intractable large cerebral aneurysms. We report our experiences with AFD. METHODS: The concept of AFD is the transformation from the bifurcation or branching sidewall type to the nonbranching sidewall type. Linearization of the parent artery by stenting, intentional branch occlusion, and aneurysmal coil embolization were performed. Furthermore, bypass surgery is performed for patients intolerant to branch occlusions. We evaluated the clinical outcomes of intractable aneurysms treated with AFD. RESULTS: AFD was performed in seven unruptured large aneurysms. Aneurysmal locations were the top of the basilar artery (BA), BA-superior cerebellar artery (SCA), internal carotid artery (IC)-posterior communicating artery (PcomA), and IC terminal. The mean dome diameter was 17.0 ± 4.6 mm. Six patients underwent bypass surgery. The occluded branches were the PCA + SCA, PcomA, and anterior cerebral artery (ACA) A1. An FD was used in three patients and a neck bridge stent in four patients. No intraprocedural complications occurred. Two postprocedural ischemic complications occurred in one patient. Six (86%) patients demonstrated a modified Rankin Scale (mRS) 0 at the 3-month follow-up, and one with an ischemic complication showed an mRS 5. Complete occlusion of all aneurysms was maintained with a median follow-up duration of 60 months. CONCLUSION: AFD is useful for intractable large cerebral aneurysms with high curability, although safety verification is required.

Endovascular Treatment of Basilar Apex Aneurysms: An Updated Systematic Review and Meta-Analysis in the Era of Flow Diversion.

BACKGROUND: Endovascular options for the treatment of basilar apex aneurysms (BAAs) are heterogeneous, and evidence is limited to retrospective cohorts and case series. We seek to evaluate the efficacy and complications associated with various endovascular treatment methods of BAAs. METHODS: Systematic review of PubMed, Embase, and Web of Science adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Retrospective and prospective studies evaluating endovascular treatment of BAAs between January 2010 and July 2024 were included. Relevant information including occlusion rates, aneurysm recurrence, retreatment rates, and complications were subjected to meta-analysis. RESULTS: Fifteen studies with 1049 BAAs were included. The median aneurysm diameter was 8.5 mm (range, 4.6-19.75), with a median follow-up of 33.7 months (range, 6.0-117.6). Residual aneurysm filling occurred in 24% after primary coiling (95% CI = 0.16-0.32), 25% after single stent-assisted coiling (s-SAC; 95% CI = 0.04-0.46), 25% after Y-stents (95% CI = 0.12-0.37), and 23% after flow diverter stent (FDS; 95% CI = 0.11-0.35). Recurrence rates were high for primary coiling (27%, 95% CI = 0.18-0.36) and s-SAC (19%, 95% CI = 0.13-0.26), but significantly lower for Y-stents (9%, 95% CI = 0.03-0.15) and FDS (4%, 95% CI = -0.04-0.11). Retreatment rates were 19% for primary coiling (95% CI = 0.12-0.26), 17% for s-SAC (95% CI = 0.07-0.27), 5% for Y-stents (95% CI = -0.03-0.12), and 13% for FDS (95% CI = -0.01-0.27). Meta-regression indicated larger aneurysms had higher complication rates (P = 0.02). Thromboembolic events were most frequent with FDS and Y-stents(12%). CONCLUSIONS: Occlusion rates were similar across treatments, but recurrence rates were significantly lower after Y-stents and FDS compared to primary coiling, although they carried a higher number of thromboembolic complications.

Flow Diversion for Endovascular Treatment of Intracranial Aneurysms: Past, Present, and Future Directions.

Flow diversion for intracranial aneurysms emerged as an efficacious and durable treatment option over the last two decades. In a paradigm shift from intrasaccular aneurysm embolization to parent vessel remodeling as the mechanism of action, the proliferation of flow-diverting devices has enabled the treatment of many aneurysms previously considered untreatable. In this review, we review the history and development of flow diverters, highlight the pivotal clinical trials leading to their regulatory approval, review current devices including endoluminal and intrasaccular flow diverters, and discuss current and expanding indications for their use. Areas of clinical equipoise, including ruptured aneurysms and wide-neck bifurcation aneurysms, are summarized with a focus on flow diverters for these pathologies. Finally, we discuss future directions in flow diversion technology including bioresorbable flow diverters, transcriptomics and radiogenomics, and machine learning and artificial intelligence.

Preliminary results of intracranial aneurysm treatment with derivo2heal embolization device.

INTRODUCTION: The Derivo 2 Heal Embolization Device (D2HED) is a novel flow diverter (FD) providing a fibrin-/heparin-based surface coating aiming at lower thrombogenicity. We evaluate periprocedural aspects and preliminary aneurysm occlusion efficacy for intracranial aneurysm treatment. METHODS: Thirty-four D2HEDs deployments (34 aneurysms, 32 patients) between 04/2021 and 10/2023 were analyzed. All patients were under dual antiplatelet therapy (dAPT). Periprocedural details, adverse events, and follow-up (FU) imaging were reviewed by consultant-level neuroradiologists. Complication rates and aneurysm occlusion efficacy are compared with performance data of other FDs based on literature research. RESULTS: Each intervention succeeded in the deployment of one D2HED. Significant and/or increased intraaneurysmal contrast stagnation immediately after D2HED deployment was seen in 73.5% of cases according to O'Kelly-Marotta (OKM) grading scale. Clinically relevant early adverse events occurred in three patients: Among them two cases with fusiform aneurysms in the posterior circulation (ischemic events, early in-stent-thrombosis) and one patient (ischemic event) out of the majority of 31 treated internal carotid artery aneurysms (3,2%). Regarding mid-term FU (> 165 days), one aneurysm did not show progressive occlusion presumably caused by a prominent A1 segment arising from the terminal ICA aneurysm itself. Apart from that, mid-term complete / partial occlusion rates of 80% / 20% could be demonstrated. CONCLUSION: Our case series - although suffering from restricted sample size - suggests a potential effectiveness of D2HED in managing intracranial aneurysms. Further studies with larger samples are warranted to quantify long-term occlusion efficacy and the impact of antithrombogenic surface coating on the necessary (d)APT.

The aneurysm occlusion and recurrence of posterior communicating artery aneurysms following the treatment with the pipeline embolization device.

Despite advancements in treatment modalities such as flow diverters, the optimal management of posterior communicating artery (PComA) aneurysms remains uncertain. While PComA aneurysms treated with the Pipeline Embolization Device (PED) has been reported, the characteristics and progression of incomplete occluded aneurysms remain unclear. Therefore, our study aims to investigate the occlusion status and recurrence rates of PComA aneurysms treated with PED. A retrospective review of consecutive PComA aneurysm patients treated with PED was conducted between January 2015 and December 2020. Only patients with radiological follow-up were included. PComA aneurysms were categorized into incomplete occlusion and complete occlusion group. The primary outcomes included the characteristics of incomplete occlusion at the follow-up angiography. Among 121 PComA aneurysms treated with PED at our institution, 80 aneurysms were eligible in our study. During the follow-up period, 19 (23.8%) aneurysms demonstrated incomplete occlusion. Notably, there were no instances of recurrence among the 80 followed-up cases. Baseline characteristics of patients and aneurysms were comparable between the groups with complete and incomplete occlusion. However, the incomplete occlusion group showed a lower rate of assisted coils embolization (21.2% vs. 55.7%, P = 0.017) and shorter median operative time (91.0 vs. 145.5 min, P = 0.039). Differences in functional outcomes, complications, and PComA occlusion status between the groups were not significant. Multivariate analysis revealed the use of coils was associated with lower odds of incomplete PComA aneurysm occlusion (OR 0.01, 95% CI 0.001-0.12; P = 0.001), while aneurysm size was associated with higher odds of incomplete occlusion (OR 1.25, 95% CI 1.10-1.46; P = 0.002). The treatment of PED for PComA aneurysm demonstrated favorable outcomes, with an acceptable rate of incomplete occlusion and no instances of recurrence observed. However, further research is needed to explore the optimal procedural strategy for large-sized PComA aneurysms.

Variability patterns in dual antiplatelet therapy following endovascular repair of intracranial aneurysms: Insight into regimen heterogeneity and the need for a consensus.

This comprehensive review delves into the evolving field of neurointervention for intracranial aneurysms, exploring the critical adjunct of Dual Antiplatelet Therapy (DAPT) to endovascular coiling, stent-assisted coiling (SAC), flow-diversion stents, and flow-disruption (intrasaccular) devices. Despite growing evidence supporting the success of DAPT in reducing thromboembolic events, the lack of consensus on optimal regimens, doses, and duration is evident. Factors contributing to this variability include genetic polymorphisms affecting treatment response and ongoing debates regarding the clinical significance of hemorrhagic complications associated with DAPT. This review analyzes pre- and post-procedural antiplatelet usage across various interventions. The imperative lies in ongoing research to define optimal DAPT durations, ensuring a nuanced approach to the delicate balance between thrombosis and hemorrhage in intracranial aneurysm management.

Endothelial Progenitor Cells: A Review of Molecular Mechanisms in the Pathogenesis and Endovascular Treatment of Intracranial Aneurysms.

This comprehensive review explores the multifaceted role of endothelial progenitor cells (EPCs) in vascular diseases, focusing on their involvement in the pathogenesis and their contributions to enhancing the efficacy of endovascular treatments for intracranial aneurysms (IAs). Initially discovered as CD34+ bone marrow-derived cells implicated in angiogenesis, EPCs have been linked to vascular repair, vasculogenesis, and angiogenic microenvironments. The origin and differentiation of EPCs have been subject to debate, challenging the conventional notion of bone marrow origin. Quantification methods, including CD34+ , CD133+ , and various assays, reveal the influence of factors, like age, gender, and comorbidities on EPC levels. Cellular mechanisms highlight the interplay between bone marrow and angiogenic microenvironments, involving growth factors, matrix metalloproteinases, and signaling pathways, such as phosphatidylinositol-3-kinase (PI3K) and mitogen-activated protein kinase (MAPK). In the context of the pathogenesis of IAs, EPCs play a role in maintaining vascular integrity by replacing injured and dysfunctional endothelial cells. Recent research has also suggested the therapeutic potential of EPCs after coil embolization and flow diversion, and this has led the development of device surface modifications aimed to enhance endothelialization. The comprehensive insights underscore the importance of further research on EPCs as both therapeutic targets and biomarkers in IAs.

Appraisal of the Flow Diversion Effect Provided by Braided Intracranial Stents.

Objective: Comparison of the results of stent-assisted coiling (SAC) with braided stents (BS), flow diverters (FD), and laser-cut stents (LCS) to determine the relative flow-diverting capacity of BS (Leo baby and Accero). Methods: Saccular intracranial aneurysms treated by SAC and FD-assisted coiling were retrospectively evaluated. Aneurysm occlusion, as graded per Raymond-Roy score, was categorized as either recanalization/stable residual filling (Group A; lacking a flow diversion effect) or stable/progressive occlusion (Group B with a "flow diversion effect"). Factors predicting the flow diversion effect were evaluated. Results: Of the 194 aneurysms included, LCS, BS, and FD were used in 70 (36.1%), 86 (44.3%), and 38 (19.6%) aneurysms, respectively. Aneurysms treated by FD were larger, had wider necks, and were located on larger parent arteries (p < 0.01, 0.02, and <0.01, respectively). The mean imaging follow-up duration was 24.5 months. There were 29 (14.9%) aneurysms in Group A and 165 (85.1%) in Group B. Among a spectrum of variables, including sex, age, aneurysm size, neck width, parent artery diameter, follow-up duration, and stent type, the positive predictors for stable/progressive aneurysm occlusion were aneurysm size and placement of an FD or BS (p < 0.01 and p < 0.01, respectively, and were positive predictors over LCS: ORs 6.34 (95% CI: 1.62-24.76) and 3.11 (95% CI: 1.20-8.07), respectively) in multivariate analysis. Conclusions: The placement of BS was a predictor of flow diversion over laser-cut stents. However, the flow diversion effect was approximately half that of FDs, suggesting that BS may only be considered to have some (partial) flow diversion effects.

Diluted contrast media combined with high-resolution C-arm CT for evaluating apposition of flow diversions in a porcine model.

BACKGROUND: In intracranial stenting, good stent apposition is crucial, and high-resolution C-arm computer tomography (CT) is utilized to assess whether stent apposition is complete. This study was aimed at finding optimal hypertonic or isotonic contrast media injection concentration for high-resolution C-arm CT to assess apposition of flow diversion (FD) after carotid artery stenting in swine. METHODS: Twelve FD stents were implanted into the left carotid artery of Bama swine through the endovascular method. During high-resolution C-arm CT scanning, 6%, 8%, 10%, 12%, and 14% dilution percentages of hypertonic contrast media (iopromide 370 mg/ml) and 10%, 12%, 14%, 16%, and 18% dilution percentages of isotonic contrast media (iodixanol 320 mg/ml) were separately injected. A radiologist and a neuro-interventional specialist evaluated and qualitatively scored the post-processed images, and intravascular ultrasound (IVUS) was used to verify the accuracy of these images. RESULTS: Overall, 12 FD stents were implanted into the left common carotid artery of 12 swine, with a technical success rate of 100%. The best reconstructed images used to observe stent apposition were achieved with iopromide diluted to a concentration of 12% (all P < .05) or iodixanol diluted to a concentration of 16% (all P < .05). Malapposition was noted in one case, and good apposition was noted in 11 cases. These results were consistent with IVUS observations. CONCLUSION: Injecting iopromide or iodixanol diluted to 12% or 16% during high-resolution C-arm CT scanning, respectively, can help evaluate FD stent apposition and obtain optimal image quality.

Delayed Iatrogenic Direct Carotid Cavernous Fistula Following Flow Diversion for Aneurysm With Spontaneous Healing: A Case Report.

An abnormal connection between the carotid artery and cavernous sinus is referred to as a carotid cavernous fistula (CCF). A direct CCF results when the connection occurs between the intracranial internal carotid artery (ICA) and the cavernous sinus. These events are typically the result of a head injury, but can also be iatrogenic, resulting from various intracranial procedures. Direct CCF occurrences rarely heal spontaneously due to the high flow rate across the fistula. In this report, we present an uncommon case involving a delayed iatrogenic direct CCF, which developed following the placement of a pipeline flow-diverting stent that was used to treat a cerebral aneurysm. Interestingly, this unusual iatrogenic direct CCF subsequently spontaneously resolved within a few months. To our knowledge, this is the only case of a delayed CCF occurring with the use of a flow-diverting sent, which then resolved on its own. This report recounts our experience with the case.

Defining light transmission aggregometry cutoff values for clopidogrel and aspirin resistance in flow diversion treatment of intracranial aneurysms.

OBJECTIVE: Concern about thromboembolic events after flow diversion (FD) warrants dual antiplatelet therapy for 3 to 6 months. Platelet function tests are routinely performed prior to the procedure to detect clopidogrel responsiveness, as resistance is associated with CYP2C19 gene polymorphisms. This study aimed to identify optimal cutoff values in light transmission aggregometry (LTA) for clopidogrel and aspirin as predictive indicators of thromboembolic complications. METHODS: The authors conducted a retrospective analysis of aneurysms treated with FD between 2013 and 2023 at a single academic institution. Patients with LTA data for adenosine diphosphate (ADP) and arachidonic acid (ARA) were included, excluding those with aborted procedures. Receiver operating characteristic curves were plotted for ADP and ARA assays to determine optimal cutoff values. RESULTS: A total of 442 patients harboring 552 aneurysms treated in 485 procedures were selected for this analysis. Complete and near-complete aneurysm occlusion on the last radiological follow-up was achieved in 81.8% of aneurysms in a median last imaging follow-up of 13.9 months. A good functional outcome (modified Rankin Scale score ≤ 2) was achieved in 96.3% of patients on the last follow-up. Thromboembolic complications occurred in 4.9% of procedures, and intracranial hemorrhagic complications in 1.9%. For the ADP assay, a value ≥ 40% reached a sensitivity of 82.1% and a specificity of 42.9% with a positive likelihood ratio (LR) of 1.50. For the ARA assay, a value ≥ 13.5% reached a sensitivity of 82.1% and a specificity of 45.6% with a positive LR of 1.51. CONCLUSIONS: This study analyzed the largest FD-treated cohort in which optimal LTA platelet function thresholds for clopidogrel were evaluated and is the first to assess LTA values for aspirin. The authors found that values ≥ 40% for clopidogrel and ≥ 13.5% for aspirin were optimal for predicting thromboembolic complications after FD in treating aneurysms.

Thromboembolic Events in the Posterior Circulation After Flow Diversion-A Closer Look at Coverage of the Posterior Cerebral Artery.

BACKGROUND: Flow diversion for bifurcation aneurysms requires excluding one of the branches from the parent artery, raising concern for ischemic events. We evaluated thromboembolic events and their relationship with covering the origin of the posterior cerebral artery (PCA). METHODS: This retrospective analysis included patients with confirmed basilar and proximal PCA aneurysms treated with flow diversion between 2013 and 2023. Procedures were classified according to the coverage of the origin of the PCA. Thromboembolic events associated with the excluded PCA were evaluated. RESULTS: Of the total 28 aneurysms included, 7 were at the basilar tip, 16 in the basilar trunk, and 5 in the first segment of the PCA; 15 were treated by excluding one of the PCAs. Dual antiplatelet therapy included aspirin and ticagrelor (57.1%), aspirin and clopidogrel (35.7%), or aspirin and prasugrel (3.57%). Complete and near-complete aneurysm occlusion was achieved in 80.8% of the aneurysms treated at a median follow-up of 12.31 months. Thromboembolic complications occurred in 3 patients (2 with basilar perforator stroke and 1 with basilar in-stent thrombosis). However, the difference in these events was not statistically significant between patients with PCA coverage and those without (P = 0.46). Diminished flow and a lack of flow was seen in 8 and 7 of the covered vessels, respectively. A modified Rankin scale score of ≤2 was reported for 89.3% of patients at a median clinical follow-up of 5.5 months. CONCLUSIONS: The incidence of thromboembolic events is high in distal basilar and proximal PCA aneurysms; however, PCA coverage was not associated with their occurrence. There was no difference in postprocedural disability between patients whose aneurysms were treated by excluding one of the PCAs and those who were not.

Thromboembolic Events After the Coverage of Anterior Cerebral Artery with Flow Diversion: A Single Institution Series and Systematic Review.

BACKGROUND: Advances in the use of flow diversion (FD) now extend to bifurcation aneurysms; herein, we compare thromboembolic events in patients with internal carotid artery (ICA) aneurysms treated with and without exclusion of the anterior cerebral artery (ACA). METHODS: Retrospective analysis of aneurysms in the terminal ICA treated with FD from 2013 to 2023 at a single-center study. Procedures were classified according to the coverage at the origin of the ACA and compared through bivariate-analysis. A review was also carried on PubMed, Web of Science, and EMBASE until April 2024, adhering to the PRISMA reporting guidelines. RESULTS: Ninety-five patients harboring 113 aneurysms treated in 102 procedures were evaluated. Fifty-eight were treated covering the ACA origin. Dual antiplatelet regimens included aspirin-clopidogrel (50%), aspirin-ticagrelor (44.1%), and aspirin-prasugrel (4.9%). Thromboembolic events occurred in 6 patients (5.9%), all of which presented with large vessel occlusion of the ICA, but without reaching statistical difference in the 2 treated cohorts (P = 0.46). At a median clinical follow-up of 5.95 months, there were no differences in the functional outcomes in the 2 groups (P = 0.22). Contralateral angiographic runs post-treatment after covering the ACA origin demonstrated increase in the A1 (median: 0.45 mm; IQR = 0.4-1.2) and ICA diameter (median: 0.55 mm; IQR = 0.1-1.2). After pooling data from literature and our cohort, complete side branch occlusion after the coverage of ACA was seen in 25% of branches (95%CI = 0.16-0.36), and thromboembolic events were observed after 3% (95%CI = 0.01-0.04) of procedures. CONCLUSIONS: Thromboembolic events can occur in distal ICA aneurysms treated with FD, but no significant association was seen with covering the ACA origin.

Use of a new low-profile coronary stent graft for the treatment of intracranial carotid blow-out.

A 50-year-old male patient with a history of transcranial surgery and subsequent radiotherapy for a pituitary adenoma presented with repetitive pulsatile nasal bleeding. A right cavernous segment pseudoaneurysm was discovered on the angiogram, and the patient failed the balloon occlusion test. A Papyrus (Biotronik, Berlin, Germany) stent graft, which is approved for coronary interventions, was successfully deployed over a coaxial guiding system during the emergent treatment of the false aneurysm. The patient tolerated the procedure well and nasal bleeding did not recur after the procedure. At one-year angiographic follow-up, the stent graft was patent and there was no evidence of recanalization of the false aneurysm.

Management of failed flow diversion for intracranial aneurysm beyond the first 6 months of follow-up: an international Delphi consensus.

OBJECTIVE: The placement of flow-diverting devices has become a common method of treating unruptured intracranial aneurysms of the internal carotid artery. The progressive improvement of aneurysm occlusion after treatment-with low complication and rupture rates-has led to a dilemma regarding the management of aneurysms in which occlusion has not occurred within 6-24 months. The authors aimed to identify clinical consensus regarding management of intracranial aneurysms displaying persistent filling 6-24 months after flow diversion and to ascertain questions that may drive future investigation. METHODS: An international panel of 67 experts was invited to participate in a multistep Delphi consensus process on the treatment of intracranial aneurysms after failed flow diversion. RESULTS: Of the 67 experts invited, 23 (34%) participated. Qualitative analysis of an initial survey with open-ended questions resulted in 51 statements regarding management of aneurysms showing persistent filling after flow diversion. The statements were grouped into 8 categories, and in the second round, respondents rated the degree of their agreement with each statement on a 5-point Likert scale. Flow diverters with surface modifiers did not influence administration of dual-antiplatelet therapy according to 83%. Consensus was also reached regarding the definition of treatment failure at specific time points, including at 6 months if there is aneurysm growth or persistent rapid flow through the entirety of the aneurysm (96%), at 12 months if there is aneurysm growth or symptom onset (78%), and at 24 months if there is persistent filling regardless of size and filling characteristics (74%). Although experts agreed that the degree of intimal hyperplasia or in-device stenosis could not be ascertained by noninvasive imaging alone (83%), only 65% chose digital subtraction angiography as the preferred modality. At 6 and 12 months, retreatment is preferred if there is persistent filling with aneurysm growth (96%, 96%), device malposition (48%, 87%), or a history of subarachnoid hemorrhage (65%, 70%), respectively, and at 24 months if there is persistent filling without reduction in aneurysm size (74%). Experts favored treatment with an additional flow diverter (87%) over aneurysm clipping, applying the same principles for follow-up (83%) and treatment failure (91%) as for the first flow diverter. CONCLUSIONS: The authors present the consensus practices of experts in the management of intracranial aneurysms without occlusion 6-24 months after treatment with a flow-diverting device.

Evaluation of flow diverter use in acutely ruptured vertebral artery dissecting Aneurysms: A focus on safety and efficacy for rapid Aneurysm obliteration.

OBJECTIVE: Flow diverter device (FDD) has emerged as the reconstruction technique for treating ruptured dissecting vertebral artery Aneurysms (VADA), but data on feasibility regarding re-rupture risk and timing of Aneurysm obliteration following FDD treatment is still limited. Therefore, this study aimed to evaluate the safety and efficacy of FDD in the treatment of VADAs presenting with subarachnoid hemorrhage (SAH). METHODS: We retrospectively reviewed patients with ruptured VADA presenting with subarachnoid hemorrhage who underwent FDD placement at our institution between 2015 and 2023. Patient demographic data, Aneurysm configuration, and occlusion status were analyzed. RESULTS: Thirteen patients with SAH from VADA rupture underwent FDD implantation. The average size of the largest diameter of the Aneurysm was 11.2 mm (range 6.5-21 mm). Eight of 13 (61.5 %) patients had their Aneurysms completely obliterated within 2 weeks after the procedure. The small dissecting Aneurysm (d = 0.636, p = 0.002) and degree of intra-Aneurysmal contrast stasis (d = 0.524, p = 0.026) were associated with rapid Aneurysm occlusion, according to the Somer's d coefficient. There were no ischemic or hemorrhagic complications at the average clinical follow-up of 28.4 months (range 5-67 months) and average angiographic follow-up of 20.1 months (range 3-60 months). A favorable outcome (mRS 0-2) was achieved in 12 patients (92.3 %). CONCLUSIONS: FDD is safe and effective for the reconstruction of acutely ruptured VADAs. In addition, our study emphasizes that small dissecting Aneurysms tend to be rapidly obliterated after flow diversion, which eliminates the risk of re-rupture during the acute phase of subarachnoid hemorrhage.