Optimal duration of dual antiplatelet therapy for stent-assisted coiling or flow diverter placement

Trans-arterial approach for neural recording and stimulation: Present and future

Neural recording and stimulation are fundamental techniques used for brain computer interfaces (BCIs). BCIs have significant potential for use in a range of brain disorders. However, for most BCIs, electrode implantation requires invasive craniotomy procedures, which have a risk of infection, hematoma, and immune responses. Such drawbacks may limit the extensive application of BCIs. There has been a rapid increase in the development of endovascular technologies and devices. Indeed, in a clinical trial, stent electrodes have been endovascularly implanted via a venous approach and provided an effective endovascular BCI to help disabled patients. Several authors have reviewed the use of endovascular recordings or endovascular BCIs. However, there is limited information on the use of trans-arterial BCIs. Herein, we reviewed the literature on the use of trans-arterial neural recording and stimulation for BCIs, and discuss their potential in terms of anatomical features, device innovations, and clinical applications. Although the use of trans-arterial recording and stimulation in the brain remains challenging, we believe it has high potential for both scientists and physicians.

Prediction and SHAP Analysis Integrating Morphological and Hemodynamic Parameters for Unruptured Intracranial Aneurysm Occlusion After Flow Diverter Treatment

BACKGROUND

Although most unruptured intracranial aneurysms (UIAs) have good prognosis after flow diverter (FD) treatment, some remain unoccluded for extended periods, posing a persistent rupture risk. This study aims to develop a predictive model for UIA occlusion after FD treatment through integrating morphological and hemodynamic parameters, which may be critical for personalized postoperative management.

METHODS

Data from patients with single UIAs treated with stand-alone FD were collected from June 2018 to December 2022 in four cerebrovascular disease centers. Morphological parameters were obtained from 3D reconstructed aneurysm models, and hemodynamic parameters were derived by computational fluid dynamics (CFD) analysis. A predictive model for aneurysm occlusion was constructed using various machine learning algorithms, including logistic regression, Random Forest, XGBoost, and K-Nearest Neighbors. Model performances were evaluated through repeated cross-validation, 0.632 bootstrap, and 0.632+ bootstrap. Shapley additive explanation (SHAP) analysis was employed to assess the contribution of each parameter to UIA occlusion.

RESULTS

Seventy-nine patients were reviewed; a total of 51 cases met the criteria, with an average age of 53.9 ± 9.9 years. The average aneurysm diameter was 3.72 ± 2.72 mm, comprising 29 occlusions and 22 non-occlusions. Five variables were selected for further modeling, including follow-up time > 6 months, aneurysm rupture ratio (ArR), occlusion ratio (OsR), parent artery wall shear stress (WSS), and the change of parent artery WSS. Logistic regression outperformed other algorithms, achieving an area under the curve (AUC) above 0.75, indicating good predictive performance. SHAP analysis revealed that the change of parent artery WSS contributed most significantly to accurate and early prediction. Additionally, a web application software was developed to assist clinicians in real-time aneurysm occlusion prediction.

CONCLUSIONS

This study developed a robust predictive model for UIA occlusion following FD treatment by integrating morphological and hemodynamic parameters, which may provide potentially valuable decision-making support for optimizing treatment strategies.

Imaging follow-up of unruptured intracranial aneurysms treated with flow diverter: Insights from a French collaborative survey

PURPOSE

The absence of standardized guidelines for imaging follow-up of unruptured intracranial aneurysms treated with flow diverters (FD) results in significant variability across centers. This survey aims to provide a comprehensive overview of current imaging follow-up practices in French academic centers.

METHODS

In April 2024, a 49-question survey was distributed to interventional neuroradiology centers in France through the trainee-led research collaborative network, Jeunes En Neuroradiologie Interventionnelle-Research Collaborative (JENI-RC). The survey covered follow-up protocols for digital subtraction angiography (DSA), magnetic resonance imaging (MRI), and computed tomography (CT), as well as potential modifications for specific cases.

RESULTS

Twenty interventional neuroradiology centers responded to the survey. Most centers (n = 14, 70 %), conducted a single systematic DSA either at 6 or 12 months post-procedure. In most centers (n = 13, 65 %), a second DSA was scheduled only based on the results of the first, specifically in cases of non-occluded aneurysm, intimal hyperplasia, or in-stent stenosis. MRI follow-up varied, with most centers (n = 12, 60 %) performing three MRIs over five years. Only two centers included CT scans in their protocols.

CONCLUSION

This survey highlights the substantial heterogeneity in imaging follow-up protocols for FD-treated unruptured intracranial aneurysms among French academic centers. The findings underscore the urgent need for standardized guidelines to harmonize practices, optimize patient outcomes, and improve resource utilization. Additionally, innovations in FD technology, advancements in MRI sequences, and the advent of photon-counting CT will likely influence follow-up practices in the near future.

Effects of calcium channel blockers on perioperative ischemic events in hypertensive patients with intracranial aneurysms undergoing neurointervention

BACKGROUND

Although calcium channel blockers (CCBs) are useful in stroke prevention, their specific role in preventing stroke in hypertensive patients with intracranial aneurysms undergoing endovascular stent placement remains unclear.

METHODS

We retrospectively examined 458 hypertensive patients with intracranial aneurysms who underwent stent treatment, drawn from a larger multicenter cohort comprising 1326 patients across eight centers. Patients were dichotomized into two groups according to use of a CCB. Propensity score matching (PSM) was performed to balance group differences in patient and aneurysm characteristics. We conducted a comparison of patient and aneurysm characteristics, ischemic complications, and clinical outcomes between the two groups.

RESULTS

The CCB and non-CCB groups comprised 279 and 179 patients, respectively. PSM resulted in 165 matched pairs. After PSM, the incidence of ischemic events within 1 month of the procedure (4.2% vs 10.9%; P=0.022) and proportion of patients with modified Rankin Scale score >2 at last follow-up (1.5% vs 7.8%; P=0.013) were significantly lower in the CCB group. Among patients treated with combination therapy, inclusion of a CCB was associated with a lower incidence of ischemic events (1.5% vs 13.3%; P=0.345), but the difference was not statistically significant after correction.

CONCLUSIONS

CCB use in hypertensive patients undergoing endovascular stenting for treatment of intracranial aneurysms is associated with a lower incidence of ischemic events and a lower incidence of unfavorable neurological outcomes, especially when used in combination therapy.

Longitudinal evaluation of neointimal formation using optical coherence tomography for an intracranial aneurysm with flow diverter placement in vivo: preliminary experience

Placement of a flow diverter (FD) has been a mainstream treatment for intracranial aneurysms. Neointimal formation in the aneurysmal neck and stent struts is important for promoting aneurysm healing and reducing ischemic complications. Although several animal studies have reported the longitudinal evaluation of neointimal formation post-FD placement using optical coherence tomography (OCT), no human studies have been published. We describe the first case of a patient with follow-up longitudinal angiography and OCT examination at 1 and 3 months post-FD placement for an internal carotid artery aneurysm. At 1 month, the OCT images showed complete neointimal formation on stent struts of the parent artery and partial neointimal formation on the neck. The aneurysm was occluded on angiography at 3 months and all stent struts were covered with neointima on OCT images. An OCT examination may provide insights regarding the mechanism underlying the healing process of aneurysms treated by an FD.

Impact of duration of dual anti-platelet therapy on risk of complications after stent-assisted coiling of unruptured aneurysms

BACKGROUND

The optimal duration for dual antiplatelet therapy (DAPT) after stent-assisted coiling (SAC) of intracranial aneurysms is unclear. Longer-term therapy may reduce thrombotic complications but increase the risk of bleeding complications.

METHODS

A retrospective review of prospectively maintained data at 12 institutions was conducted on patients with unruptured intracranial aneurysms who underwent SAC between January 1, 2016 and December 31, 2020, and were followed ≥6 months postprocedure. The type and duration of DAPT, stent(s) used, outcome, length of follow-up, complication rates, and incidence of significant in-stent stenosis (ISS) were collected.

RESULTS

Of 556 patients reviewed, 450 met all inclusion criteria. Nine patients treated with DAPT <29 days after SAC and 11 treated for 43-89 days were excluded from the final analysis as none completed their prescribed duration of treatment. Eighty patients received short-term DAPT. There were no significant differences in the rate of thrombotic complications during predefined periods of risk in the short, medium, or long-term treatment groups (1/80, 1.3%; 2/188, 1.1%; and 0/162, 0%, respectively). Similarly, no differences were found in the rate of hemorrhagic complications during period of risk in any group (0/80, 0%; 3/188, 1.6%; and 1/162, 0.6%, respectively). Longer duration DAPT did not reduce ISS risk in any group.

CONCLUSIONS

Continuing DAPT >42 days after SAC did not reduce the risk of thrombotic complications or in-stent stenosis, although the risk of additional hemorrhagic complications remained low. It may be reasonable to discontinue DAPT after 42 days following non-flow diverting SAC of unruptured intracranial aneurysms.

Managing thrombosis risk in flow diversion: A review of antiplatelet approaches

Flow diversion is a transformative approach in neurointerventional surgery for intracranial aneurysms that relies heavily on effective antiplatelet therapy. The ideal approach, including the timing of treatment, the use of dual antiplatelet therapy (DAPT), and the number of flow-diverter devices to use, remains unknown. DAPT, which combines aspirin with a thienopyridine like clopidogrel, prasugrel, or ticagrelor, is the standard regimen, balancing thromboembolic protection and hemorrhagic risk. The variable response to clopidogrel, influenced by genetic polymorphisms, necessitates personalized treatment strategies. Alternatives like prasugrel and ticagrelor provide superior efficacy in specific scenarios but require careful consideration of bleeding risks and costs. Platelet function testing plays a critical role in tailoring antiplatelet regimens for patients undergoing flow diversion for intracranial aneurysms. Special considerations were made for ruptured aneurysms, and the implications of the extensive metallic surface of flow diverters on platelet activation were noted. Emerging technologies such as drug-eluting flow diverters and reversal agents for P2Y12 inhibitors suggest a potential shift toward more refined antiplatelet strategies in the future. Personalized medication that is compatible with the stent structure and metal is essential for optimizing patient outcomes in cerebral flow diversion procedures. Ongoing research and multidisciplinary collaboration will be key in refining these strategies and enhancing the safety and efficacy of neurointerventional treatments.

Comparative Analysis of Stent-Assisted Versus Non-Stent-Assisted Coiling in the Management of Ruptured Intracranial Aneurysms: A Systematic Review and Meta-Analysis

OBJECTIVE

To systematically evaluate the safety and efficacy of SAC compared to non-SAC in the treatment of RIA, integrating evidence from high-quality studies to guide clinical practice.

METHODS

A meta-analysis was conducted to compare SAC with coiling alone and BAC in the treatment of RIA. Primary outcomes were immediate and follow-up aneurysm occlusion rates, along with perioperative hemorrhagic and ischemic complication rates.

RESULTS

A total of thirteen retrospective cohort studies were included, comprising 3,086 patients, with 1,078 in the SAC group and 2,008 in the non-SAC group. The immediate complete occlusion rates were similar between the SAC and non-SAC groups (59.1% vs. 61.4%; RR = 1.00; 95% CI [0.94, 1.07]; p = 0.92). However, the SAC group demonstrated a significantly higher long-term complete occlusion rate (61.3% vs. 40.6%; RR = 1.44; 95% CI [1.22, 1.69]; p < 0.001). The incidence of ischemic complications was greater in the SAC group (12.2% vs. 10.0%; RR = 1.68; 95% CI [1.37, 2.07]; p < 0.001), as was the incidence of hemorrhagic complications (7.3% vs. 5.1%; RR = 1.55; 95% CI [1.15, 2.08]; p = 0.004). Perioperative mortality was also elevated in the SAC group (6.7% vs. 6.8%; RR = 1.37; 95% CI [1.00, 1.88]; p = 0.048), with a non-significant trend towards higher long-term mortality (9.8% vs. 9.2%; RR = 1.35; 95% CI [0.98, 1.87]; p = 0.068). Functional outcomes at discharge (76.0% vs. 71.0%; RR = 0.97; 95% CI [0.92, 1.02]; p = 0.237), six months (57.8% vs. 60.8%; RR = 0.93; 95% CI [0.81, 1.07]; p = 0.296), and at the last follow-up (RR = 1.01; 95% CI [0.97, 1.06]; p = 0.592) were comparable between the two groups.

CONCLUSIONS

SAC significantly improves long-term occlusion rates for RIA compared to non-SAC, despite a higher incidence of complications. Careful patient selection and optimization of antiplatelet therapy may enhance the safety and efficacy of SAC for RIA treatment.

Evaluating the Safety of Stent-Assisted Endovascular Treatment for Unruptured Cerebral Aneurysms in Older Adults: Emphasizing the Role of Antiplatelet Therapy

INTRODUCTION

This study aimed to compare the outcomes and safety in patients aged ≥75 years and those aged <75 years who underwent stent-assisted endovascular treatment for unruptured cerebral aneurysms, specifically focusing on perioperative antiplatelet therapy (APT).

METHODS

This multicenter retrospective study comprised patients who underwent stent-assisted coiling (SAC) or flow diverter stent (FDS) placement for unruptured cerebral aneurysms. The primary outcome was defined as the composite outcomes of perioperative thromboembolic events, bleeding events, or death.

RESULTS

Among 632 patients, 533 (84.3%) were aged <75 years and 99 (15.6%) were aged ≥75 years. No significant differences were observed in the dual APT duration. The primary outcome occurred in 14.3% of patients aged <75 years and in 14.1% of those aged ≥75 years, with no significant difference (p = 1.0). The composites of the primary outcome, including thromboembolic events, bleeding events, and death differed insignificantly. Similar findings were observed when the primary outcomes for SAC (12.7% vs. 11.5%, p = 0.95) and FDS (17.5% vs. 18.4%, p = 1.0) were analyzed. The 30-day, 1-year, and 2-year cumulative event-free survival rates for the primary outcome were 89.5, 87.2%, and 85.2%, respectively, in patients aged <75 years, and 90.9%, 88.7%, and 87.0%, respectively, in those aged ≥75 years. These trends were similar (log-rank test, p = 0.92).

CONCLUSION

No significant differences were observed in the rates of the primary outcomes between patients aged <75 years and those aged ≥75 years. Therefore, refraining from stent-assisted treatment for unruptured aneurysms based solely on age might be inappropriate.

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.

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.

Antiplatelet Therapy in Endovascular Treatment of Cerebral Aneurysms

Thromboembolism is one of the main causes of severe complications in the endovascular treatment of cerebral aneurysms, and antiplatelet therapy (APT) is necessary to prevent such complications. Conversely, prolonged APT has the potential risk of hemorrhagic complications; therefore, the timing of dose reduction or discontinuation is an important aspect of periprocedural APT. However, no clinical evidence of an optimal regimen of APT for cerebral aneurysms exists, and the selection, dosage, duration, or combination of antiplatelets has been dependent on physicians for unruptured or ruptured cerebral aneurysms. Many reports have shown that preoperative APT can reduce ischemic complications without increasing hemorrhagic complications, and some reports have shown that the P2Y12 reaction unit (PRU) value measured using the VerifyNow (Werfen, Barcelona, Spain) system is associated with periprocedural ischemic and hemorrhagic complications. Appropriate dose and duration management adjustments based on the platelet reactivity test, aneurysm morphology, treatment, and patient background may contribute to good outcomes. Although accumulating evidence exists regarding the efficacy of preoperative APT, there is no evidence regarding the optimal duration or discontinuation of APT.

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.

Duration of dual-antiplatelet therapy after stent-assisted coil for unruptured intracranial aneurysm: A nationwide cohort study

BACKGROUND

Stent-assisted coil (SAC) is increasingly used to treat unruptured intracranial aneurysm (UIA). However, the optimal duration of dual-antiplatelet therapy (DAPT) after SAC insertion remains unknown.

AIM

To assess the time-dependent effect of DAPT on the risk of ischemic and hemorrhagic complications after SAC.

METHODS

This is a retrospective cohort study among patients with UIA treated with SAC using the nationwide health claims database in South Korea between 2009 and 2020. Multivariate Cox regression analysis was used, which included the use of DAPT as a time-dependent variable. The effect of DAPT was investigated for each period of "within 90 days," "91 to 180 days," "181 to 365 days," and "366 to 730 days" after SAC. The primary outcome was a composite of ischemic stroke and major bleeding in each period within two years after SAC.

RESULTS

Of the 15,918 patients, mean age at SAC was 57.6 ± 10.8 years, and 3815 (24.0%) were men. The proportion of patients on DAPT was 79.4% at 90 days, 58.3% at 180 days, and 28.9% at 1 year after SAC. During the 2 years after SAC, the primary composite outcome occurred in 356 patients (2.2%). DAPT significantly reduced the primary composite outcome within 90 days after SAC (adjusted hazard ratio (aHR), 0.44; 95% confidence interval (CI), 0.28-0.69; p < 0.001); however, this was not the case after 90 days (all p > 0.05). DAPT reduced ischemic stroke risk within 90 days (aHR, 0.31; 95% CI 0.18-0.54; p < 0.001), and 91 to 180 days after SAC (aHR 0.40; 95% CI 0.18-0.88; p = 0.022); however, after 180 days, DAPT was no longer beneficial.

CONCLUSIONS

In patients with UIA treated with SAC, 3 months of DAPT was associated with a decreased risk of the composite of ischemic and hemorrhagic complications.