Antiplatelet Premedication for Stent-Assisted Coil Embolization of Intracranial Aneurysms: Low-Dose Prasugrel vs Clopidogrel

Clopidogrel versus newer P2Y12 inhibitors in the dual antiplatelet therapy for stent-assisted coil embolization of intracranial aneurysms: A meta-analysis

INTRODUCTION

Stent-assisted coil embolization (SACE) for cerebral aneurysms requires dual antiplatelet therapy (DAPT), commonly clopidogrel plus aspirin is preferable to ticagrelor or prasugrel plus aspirin. However, there are few studies assessing the safety of the association of ticagrelor or prasugrel plus aspirin.

OBJECTIVES

Compare the safety of newer P2Y12 inhibitors with clopidogrel in patients that underwent a SACE for cerebral aneurysms.

METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we searched PubMed and Embase for studies comparing newer P2Y12 inhibitors with clopidogrel in patients undergoing DAPT for SACE. Outcomes were total number of complications, number of hemorrhagic complications, and number of thromboembolic complications both intraoperative and follow-up. A random effects model was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

We included 1026 patients from six studies. Newer P2Y12 inhibitors were used in 562 (54,77%) patients. There were no significant differences between groups in total number of complications (OR 0.80; 95% CI 0.32, 1.99; p < 0.01; I2 = 78%), in intraoperative hemorrhagic complications (OR 0.66; 95% CI 0.09, 4.71; p = 0.68; I2 = 0%), follow-up hemorrhagic complications (OR 1.23; 95% CI 0.70, 2.15; p = 0.49; I2 = 0%), intraoperative thromboembolic complications (OR 0.43; 95% CI 0.14, 1.35; p = 0.25; I2 = 24%), and in follow-up thromboembolic complications (OR 0.89; 95% CI 0.33, 2.39; p = 0.03; I2 = 59%).

CONCLUSION

In patients who underwent a SACE, newer P2Y12 inhibitors showed no differences in intraoperative and follow-up complications compared with clopidogrel.

Efficacy and Safety of Dual Antiplatelet Therapy with the Routine Use of Prasugrel for Flow Diversion of Cerebral Unruptured Aneurysms

PURPOSE

Prasugrel is not approved for patients treated with flow diverters, which have a high metal coverage ratio. However, robust antiplatelet therapy with prasugrel may prevent thromboembolic complications. We administered prasugrel and aspirin to all patients treated with flow diverters and reported the safety of the antiplatelet therapy regimen.

METHODS

This retrospective, single-center study evaluated the angiographic and clinical data of consecutive patients treated with flow diverters for cerebral unruptured aneurysms between June 2020 and May 2022. All patients received dual antiplatelet therapy, including prasugrel and aspirin. The administration of prasugrel ended 3 or 6 months after the procedure, whereas aspirin use continued for at least 12 months. Periprocedural complications (< 30 days post-procedure) and delayed complications (> 30 days post-procedure) were recorded.

RESULTS

During the study period, 120 unruptured aneurysms were treated with flow diverters in 110 patients. All patients, except one, survived longer than 12 months after the procedure. The rate of thromboembolic complications was 6.4%, and more than half of the patients had transient symptoms; one (0.9%) had a major ischemic stroke. One patient (0.9%) each had an asymptomatic, small subarachnoid hemorrhage and significant hemorrhagic complications with melena. The rate of permanent neurological deficits was 1.8%, and the mortality rate was 0.9%.

CONCLUSIONS

Dual antiplatelet therapy comprising routine use of prasugrel and aspirin for flow diverter-implanted patients possibly contributed to a low rate of thromboembolic complications and low risk of hemorrhagic complications.

Trends in the Age of Patients Treated for Unruptured Intracranial Aneurysms from 1990 to 2020

BACKGROUND

The decision for treatment for unruptured intracranial aneurysms (UIAs) is often difficult. Innovation in endovascular devices have improved the benefit-to-risk profile especially for elderly patients; however, the treatment guidelines from the past decade often recommend conservative management. It is unknown how these changes have affected the overall age of the patients selected for treatment. Herein, we aimed to study potential changes in the average age of the patients that are being treated over time.

METHODS

A systematic search of the literature was performed to identify all studies describing the age of the UIAs that were treated by any modality. Scatter diagrams with trend lines were used to plot the age of the patients treated over time and assess the presence of a potential significant trend via statistical correlation tests.

RESULTS

A total of 280 studies including 83,437 UIAs treated between 1987 and 2021 met all eligibility criteria and were entered in the analysis. Mean age of the patients was 55.5 years, and 70.7% were female. There was a significant increasing trend in the age of the treated patients over time (Spearman r: 0.250; P < 0.001), with a 1-year increase in the average age of the treated patients every 5 years since 1987.

CONCLUSIONS

The present study indicates that based on the treated UIA patient data published in the literature, older UIAs are being treated over time. This trend is likely driven by safer treatments while suggesting that re-evaluation of certain UIA treatment decision scores may be of great interest.

Safety and efficacy of tailored antiplatelet therapy using prasugrel or ticagrelor based on clopidogrel responsiveness in endovascular treatment for intracranial aneurysms: a meta-analysis

BACKGROUND

Clopidogrel (CPG)-based dual antiplatelet therapy (DAPT) in combination with aspirin has been widely used before endovascular procedures for intracranial aneurysms to prevent procedural thromboembolic complication (TEC). However, the main drawback of CPG is the high proportion of hyporesponders. This study sought to investigate the usefulness of tailored DAPT using novel P2Y12 inhibitors (prasugrel or ticagrelor, (PSG/TCG)) guided by a platelet reactivity test (PRT), compared with CPG-based conventional DAPT.

METHOD

Data were extracted from PubMed, Embase, and Cochrane Central Register of Controlled Trials by two independent reviewers. A random effects model was used to investigate the procedural TEC and hemorrhagic complications (HEC) of the tailored DAPT and conventional therapy by risk ratios (RR) and 95% confidence intervals (95% CI). Additionally, we performed subgroup analyses to directly compare prasugrel/ticagrelor with CPG.

RESULTS

Six studies comprising 2557 patients were included in the analysis. Compared with conventional non-tailored therapy, PRT-guided tailored DAPT with PSG/TCG was associated with a lower risk of TEC (RR 0.40, 95% CI 0.22 to 0.74, P=0.004) without increasing HEC rates. The subgroup analysis showed that the switch to PSG/TCG in CPG hyporesponders was related to a lower incidence of TEC (RR 0.46, 95% CI 0.23 to 0.95, P=0.03) without a difference in HEC, compared with maintenance of CPG in CPG responders.

CONCLUSION

Evidence from this analysis supports PRT-guided tailored DAPT (using PSG/TCG) as a better choice for preparation towards endovascular procedures to treat aneurysms. Furthermore, it suggests that PSG/TCG is not limited to the role of a substitute for CPG but may be a first-line agent for DAPT.

Variability of response on prophylactic prasugrel for endovascular treatment of intracranial aneurysms: Clinical implications

BACKGROUND AND PURPOSE

Prophylactic prasugrel for endovascular treatment of intracranial aneurysms has been introduced and increased, but HTPR (high on-treatment platelet reactivity) or LTPR (low on-treatment platelet reactivity) of prasugrel is not uncommon in clinical circumstances. To investigate the predisposing factors of HTPR and LTPR on prasugrel premedication in the neurointerventional field and to determine its clinical implications.

MATERIALS AND METHODS

Between February 2016 and December 2020, 191 patients treated with coil embolization using prophylactic prasugrel in 234 intracranial aneurysms were the final candidates for this study. Patient and aneurysm characteristics, clinical status, and laboratory study values were carefully reviewed retrospectively. We performed risk factor analyses for HTPR and LTPR on prasugrel.

RESULTS

Ultimately, 20 patients (10.5%) had HTPR, and 74 patients (38.7%) were categorized as having LTPR. In multivariable analyses, the factors related to HTPR were BMI (adjusted OR 1.21, 95% CI 1.04-1.41, p = 0.01), history of antithrombotics (adjusted OR 3.79, 95% CI 1.39-10.34, p = 0.01), and hematocrit (adjusted OR 0.91, 95% CI 0.84-0.99, p = 0.03). Low BMI was the only risk factor for LTPR (adjusted OR 0.84, 95% CI 0.76-0.94, p = 0.001).

CONCLUSION

In the neurointerventional field, high BMI and prior use of antithrombotic agents were related to HTPR, and low BMI was associated with LTPR on prophylactic prasugrel. High hematocrit levels decreased the risk of HTPR. When preparing endovascular treatment for intracranial aneurysms, attention to patients with these clinical features is required to address the possibility of ischemic or bleeding complications.

Effect of Stent Porosity, Platelet Function Test Usage, and Dual Antiplatelet Therapy Duration on Clinical and Radiographic Outcomes After Stenting for Cerebral Aneurysms: A Meta-Analysis

BACKGROUND

The use of stents with various porosities for treating cerebral aneurysms requires dual antiplatelet therapy (DAPT) without clear guidelines on the utility of platelet function tests (PFTs) and the duration of DAPT. We sought to determine the effects of stent porosity, PFT usage, and DAPT duration on the radiographic and clinical outcomes after stenting of cerebral aneurysms.

METHODS

PubMed was searched on March 29, 2021 for studies of cerebral aneurysm stenting that had specified the stent type and DAPT duration. A random effects meta-analysis was used to measure the prevalence of nonprocedural thrombotic and hemorrhagic events, clinical outcomes, aneurysm occlusion, and in-stent stenosis stratified by stent porosity, PFT usage, and DAPT duration.

RESULTS

The review yielded 105 studies (89 retrospective and 16 prospective) with 117 stenting cohorts (50 high porosity, 17 intermediate porosity, and 50 low porosity). In the high-, intermediate-, and low-porosity stenting cohorts, PFT usage was 26.0%, 47.1%, and 62.0% and the mean DAPT duration was 3.51 ± 2.33, 3.97 ± 1.92, and 5.18 ± 2.27 months, respectively. The intermediate-porosity stents showed a reduced incidence of hemorrhagic events (π = 0.32%) compared with low-porosity stents (π = 1.36%; P = 0.01) and improved aneurysm occlusion (π = 6.18%) compared with high-porosity stents (π = 14.42%; P = 0.001) and low-porosity stents (π = 11.71%; P = 0.04). The prevalence of in-stent stenosis was lower for the intermediate-porosity (π = 0.57%) and high-porosity (π = 1.51%) stents than for the low-porosity stents (π = 3.30%; P < 0.05). PFT use had resulted in fewer poor clinical outcomes (π = 3.54%) compared with those without PFT use (π = 5.94%; P = 0.04). The DAPT duration had no effect on the outcomes.

CONCLUSIONS

In the present meta-analysis, which had selected for studies of cerebral aneurysm stenting that had reported the DAPT duration, intermediate-porosity stents and PFT use had resulted significantly improved outcomes. No effect of DAPT duration could be detected.

Safety and Efficacy of Low-dose Prasugrel in the Endovascular Treatment of Unruptured Aneurysms in the Elders (≥ 75 Years)

PURPOSE

The effectiveness and safety of low-dose prasugrel (PSG) premedication for endovascular treatment of unruptured intracranial aneurysms (UIAs) have been widely reported. In this study, we evaluated the clinical outcomes of elders patients (≥ 75 years) treated with PSG.

METHODS

A total of 200 patients with 209 UIAs who were administered PSG as premedication (20 mg loading and 5 mg maintenance with 100 mg aspirin) between March 2018 and December 2021 were retrospectively enrolled. Among them, 39 patients were aged 75 years or over (elders group), and 161 patients were aged under 75 years (control group). Patients' clinical data were collected, and outcomes were compared between the two groups.

RESULTS

Of the 200 patients with PSG, 9 cases (4.5%) had overall complications (7 ischemic, 2 hemorrhagic). In the comparison between the elders group and the control group, no significant differences were observed in the overall complication rates (elders group vs. control group; 2.6% vs. 5.0%, P = 1.00). Moreover, the rates of poor clinical outcome were comparable (2.6% vs. 1.2%, P = 0.48). The subgroup analysis of patients with stent-assisted procedures revealed no significant differences in complication rates (0% vs. 1.6%, P = 1.00) or poor clinical outcomes (0% vs. 0%, P = 1.00) during maintenance with aspirin 100 mg or PSG 5 mg.

CONCLUSION

The complication rates in the elders treated with low-dose PSG premedication were similar to those in the control. Low-dose PSG premedication could be prescribed without any additional risk for the endovascular treatment of UIAs in elders patients.

Ticagrelor versus clopidogrel in stent-assisted coil embolization of unruptured intracranial aneurysms

BACKGROUND

Dual antiplatelet therapy is widely used for stent-assisted coil embolization (SACE) for unruptured intracranial aneurysms (UIAs) to prevent thromboembolic events (TEs). Compared to clopidogrel associated with aspirin, knowledge of the safety and efficacy of ticagrelor is lacking in large studies to date.

METHODS

A retrospective cohort study was conducted from January 2016 to December 2018 with at least one year of follow-up in a single institution and systemic review.

RESULTS

Altogether, 153 patients with UIA receiving SACE were separated into two groups: 113 patients receiving clopidogrel plus aspirin and 40 patients receiving ticagrelor plus aspirin. Acute in-stent thrombotic events were noted in two patients in the clopidogrel group (1.77%) and none in the ticagrelor group (0%). Additionally, one patient (0.88%) in the clopidogrel group had an early ischemic stroke (<3 months). Delayed ischemic stroke was noted in 6 patients (5.31%) in the clopidogrel group and 3 patients (7.50%) in the ticagrelor group. There were no major hemorrhagic events in either group. The two groups showed no significant differences with regard to ischemic stroke or hemorrhagic stroke.

CONCLUSION

Compared to the clopidogrel based regimen, ticagrelor can also reduce TEs without increasing bleeding tendency for SACE of UIAs. Ticagrelor combined with low-dose aspirin is a safe and effective alternative option for SACE.

Safety of Oral P2Y12 Inhibitors in Interventional Neuroradiology: Current Status and Perspectives

In the field of interventional neuroradiology, antiplatelet agents are commonly used to prepare patients before the implantation of permanent endovascular materials. Among the available drugs, clopidogrel is the most frequently used one, but resistance phenomena are considered to be relatively common. Prasugrel and ticagrelor were recently added to the pharmacologic arsenal, but the safety of these agents in patients undergoing neurointerventional procedures is still a subject of discussion. The cumulative experience with both drugs is less extensive than that with clopidogrel, and the experience with patients in the neurology field is less extensive than in the cardiology domain. In the present article, we provide a narrative review of studies that investigated safety issues of oral P2Y12 inhibitors in interventional neuroradiology and discuss potential routes for future research.

Midterm Outcomes After Low-Profile Visualization Endoluminal Support or Atlas Stent-Assisted Coiling of Intracranial Aneurysms: A Propensity Score Matching Analysis

BACKGROUND

The interplay of various commercially available stents during coil embolization of intracranial aneurysms and their ultimate impact are subject to debate.

OBJECTIVE

To compare midterm outcomes of Low-Profile Visualization Endoluminal Support (LVIS) (MicroVention Inc) and Atlas (Stryker) stent-assisted coiling procedures.

METHODS

A total of 459 intracranial aneurysms subjected to coil embolization using LVIS (n = 318) or Atlas stents (n = 141) between April 2015 and December 2019 were eligible for study. To assess occlusive status postembolization, magnetic resonance angiography and/or conventional angiography were used. The Raymond classification was applied to categorize recanalization. Our analysis was propensity score matched according to probability of stent type deployed.

RESULTS

Eventually, 41 aneurysms (8.9%) displayed recanalization (minor, 28; major, 13) 6 mo after coiling. Patient age (P = .018), sex (P = .015), aneurysmal location (P < .001), and type of aneurysm (P < .001) differed significantly by group. Overall and major recanalization rates at midterm were similar in both groups (9.1% and 8.5% vs 3.1% and 2.1%, respectively), and there was no significant difference even after 1:1 propensity score matching (odds ratio [OR] = 0.75 [P = .514] and OR = 0.75 [P = .706], respectively).

CONCLUSION

In stent-assisted coil embolization of intracranial aneurysms, midterm outcomes of LVIS and Atlas device groups were similar, despite theoretic LVIS superiority. Further randomized comparative studies are needed to confirm our findings.

P2Y12 inhibitors for the neurointerventionalist

The use of antiplatelets is widespread in clinical practice. However, for neurointerventional procedures, protocols for antiplatelet use are scarce and practice varies between individuals and institutions. This is further complicated by the quantity of antiplatelet agents which differ in route of administration, dosage, onset of action, efficacy and ischemic and hemorrhagic complications. Clarifying the individual characteristics for each antiplatelet agent, and their associated risks, will increasingly become relevant as the practice of mechanical thrombectomy, stenting, coiling and flow diversion procedures grows. The aim of this review is to summarize the existing literature for the use of P2Y12 inhibitors in neurointerventional procedures, examine the quality of the evidence, and highlight areas in need of further research.

Dual Testing to Achieve Low On-treatment Platelet Reactivity for Aneurysm Embolization

BACKGROUND AND PURPOSE

Although point-of-care tests are used extensively to test platelet function before endovascular aneurysm treatment, their use and validity are still debated. We compared the results of two point-of-care tests (VerifyNow® and Multiplate®) for assessing patients treated with stents and flow diverters and determined their relation to periprocedural complications.

METHODS

All patients undergoing treatment of intracranial aneurysms were tested using both methods and were retrospectively evaluated. Patients with acute subarachnoid hemorrhage and those who had to be maintained on anticoagulants for unrelated diseases were excluded. An acceptable level of platelet inhibition was required on both tests to commence with treatment, otherwise antiplatelet medication was adjusted to reach this level.

RESULTS

Mean PRU (platelet reactivity units) and ADP AUC (adenosine diphosphate area under the aggregation curve) were 68 ± 66 and 23 ± 15, respectively, in 295 patients. Both tests showed a good correlation (r = 0.45). Both tests were able to predict hemorrhagic events but not ischemic events. When patients with very low reactivity (PRU < 60) were compared to the rest of the group, there were more hemorrhagic events in the first group but the overall rate of complications were similar (p = 0.27).

CONCLUSION

In this largest study comparing two widely used commercial platelet function tests, the correlation between the tests were less than ideal; however, the very low platelet reactivity attained by the help of dual platelet testing did not result in an increased overall complication rate.

Antiplatelet Drugs for Neurointerventions: Part 2 Clinical Applications

Endovascular techniques have expanded to include balloon and stent-assistance, flow diversion and individualized endovascular occlusion devices, to widen the treatment spectrum for more complex aneurysm morphologies. While usually well-tolerated by patients, endovascular treatment of intracranial aneurysms carries the risk of complications, with procedure-related ischemic complications being the most common. Several antiplatelet agents have been studied in a neurointerventional setting for both prophylaxis and in the setting of intraprocedural thrombotic complications. Knowledge of these antiplatelet agents, evidence for their use and common dosages is important for the practicing neurointerventionist to ensure the proper application of these agents.Part one of this two-part review focused on basic platelet physiology, pharmacology of common antiplatelet medications and future directions and therapies. Part two focuses on clinical applications and evidence based therapeutic regimens.

Reduction of thromboembolic complications during the endovascular treatment of unruptured aneurysms by employing a tailored dual antiplatelet regimen using aspirin and prasugrel

Background

Thromboembolic complications (TECs) are frequent during the endovascular treatment of unruptured aneurysms. To prevent TECs, dual antiplatelet therapy using aspirin and clopidogrel is recommended for the perioperative period. In patients with a poor response, clopidogrel is a risk factor for TECs. To prevent TECs, our study assessed the stratified use of prasugrel.

Methods

Patients who underwent endovascular therapy for unruptured cerebral aneurysms from April 2017 to August 2019 were enrolled in this clinical study and given premedication with aspirin and clopidogrel for 2 weeks prior to the procedure. P2Y12 reaction units (PRU) were measured using the VerifyNow assay on the day before the procedure (tailored group). In subgroups with PRU <240, the clopidogrel dose was maintained (CPG subgroup). In subgroups with PRU ≥240, clopidogrel was changed to prasugrel (PSG subgroup). We compared the occurrence of TECs with retrospective consecutive cases from January 2015 to March 2017 without PRU assessments (non-tailored group). The frequency of TECs within 30 days was assessed as the primary endpoint.

Results

The tailored and non-tailored groups comprised 167 and 50 patients, respectively. TECs occurred in 11 (6.6%) and 8 (16%) patients in the tailored and non-tailored groups (P=0.048), respectively. The HR for TECs was significantly reduced in the tailored group (HR 0.3, 95% CI 0.11 to 0.81); P=0.017) compared with the non-tailored group.

Conclusion

The results suggest that tailored dual antiplatelet therapy medication with PRU significantly reduces the frequency of TECs without increasing hemorrhagic complications.

CD31 Mimetic Coating Enhances Flow Diverting Stent Integration into the Arterial Wall Promoting Aneurysm Healing

BACKGROUND AND PURPOSE

Beyond aneurysmal occlusion, metallic flow diverters (FDs) can induce an adverse endovascular reaction due to the foreignness of metal devices, hampering FD endothelialization across the aneurysm neck, and arterial healing of intracranial aneurysms. Here, we evaluated the potential benefits of an FD coating mimicking CD31, a coreceptor critically involved in endothelial function and endovascular homeostasis, on the endothelialization of FDs implanted in vivo.

METHODS

Nitinol FD (Silk Vista Baby) and flat disks were dip-coated with a CD31-mimetic peptide via an intermediate layer of polydopamine. Disks were used to assess the reaction of endothelial cells and blood elements in vitro. An aneurysm rabbit model was used to compare in vivo effects on the arterial wall of CD31-mimetic-coated (CD31-mimetic, n=6), polydopamine-coated (polydopamine, n=6), and uncoated FDs (bare, n=5) at 4 weeks post-FD implantation. In addition, long-term safety was assessed at 12 weeks.

RESULTS

In vitro, CD31-mimetic coated disks displayed reduced adhesion of blood elements while favoring endothelial cell attachment and confluence, compared to bare and polydopamine disks. Strikingly, in vivo, the neoarterial wall formed over the CD31-mimetic-FD struts at the aneurysm neck was characteristic of an arterial tunica media, with continuous differentiated endothelium covering a significantly thicker layer of collagen and smooth muscle cells as compared to the controls. The rates of angiographic complete occlusion and covered branch arterial patency were similar in all 3 groups.

CONCLUSIONS

CD31-mimetic coating favors the colonization of metallic endovascular devices with endothelial cells displaying a physiological phenotype while preventing the adhesion of platelets and leukocytes. These biological properties lead to a rapid and improved endothelialization of the neoarterial wall at the aneurysm neck. CD31-mimetic coating could therefore represent a valuable strategy for FD biocompatibility improvement and aneurysm healing.

Antiplatelet Management for Stent-Assisted Coiling and Flow Diversion of Ruptured Intracranial Aneurysms: A DELPHI Consensus Statement

BACKGROUND AND PURPOSE

There is a paucity of data regarding antiplatelet management strategies in the setting of stent-assisted coiling/flow diversion for ruptured intracranial aneurysms. This study aimed to identify current challenges in antiplatelet management during stent-assisted coiling/flow diversion for ruptured intracranial aneurysms and to outline possible antiplatelet management strategies.

MATERIALS AND METHODS

The modified DELPHI approach with an on-line questionnaire was sent in several iterations to an international, multidisciplinary panel of 15 neurointerventionalists. The first round consisted of open-ended questions, followed by closed-ended questions in the subsequent rounds. Responses were analyzed in an anonymous fashion and summarized in the final manuscript draft. The statement received endorsement from the World Federation of Interventional and Therapeutic Neuroradiology, the Japanese Society for Neuroendovascular Therapy, and the Chinese Neurosurgical Society.

RESULTS

Data were collected from December 9, 2019, to March 13, 2020. Panel members achieved consensus that platelet function testing may not be necessary and that antiplatelet management for stent-assisted coiling and flow diversion of ruptured intracranial aneurysms can follow the same principles. Preprocedural placement of a ventricular drain was thought to be beneficial in cases with a high risk of hydrocephalus. A periprocedural dual, intravenous, antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor was preferred as a standard approach. The panel agreed that intravenous medication can be converted to oral aspirin and an oral P2Y12 inhibitor within 24 hours after the procedure.

CONCLUSIONS

More and better data on antiplatelet management of patients with ruptured intracranial aneurysms undergoing stent-assisted coiling or flow diversion are urgently needed. Panel members in this DELPHI consensus study preferred a periprocedural dual-antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor.

Use of pCONUS HPC for the treatment of unruptured wide-necked bifurcation aneurysms: early clinical experience using single antiplatelet therapy

BACKGROUND

In recent years, a growing number of stents and stent-like devices have become available to facilitate the treatment of challenging aneurysms. However, the need for dual antiplatelet therapy can limit their use, especially in ruptured aneurysms. The hydrophilic polymer coating (pHPC, phenox) is a novel glycan-based multilayer polymer that reduces platelet adhesion. This study aims to report our initial experience using the pCONUS HPC device for the treatment of unruptured wide-necked bifurcation aneurysms (WNBA) using acetylsalicylic acid (ASA) as single antiplatelet therapy (SAPT).

METHODS

We retrospectively identified all patients who were treated with the pCONUS HPC for unruptured WNBA in a multi-staged procedure using ASA as SAPT. Records were made of periprocedural complications, clinical outcome and angiographic and clinical follow-up.

RESULTS

We identified 15 patients with 15 WNBA. The average age was 69 years old (range, 41-76). Seven aneurysms were located in the middle cerebral artery, five in the anterior communicating artery, two at the basilar tip and one in the posterior communicating artery. Immediate post-treatment angiography showed five aneurysms with modified Raymond-Roy classification (mRRC) grade I and four aneurysms with mRRC grade II. There were no haemorrhagic complications. Four patients developed thrombus formation during the second treatment session, all of them completely resolving after administration of glycoprotein IIb/IIIa antagonists. Angiographic follow-up data were available for 10 patients and showed adequate occlusion (mRRC I or II) in eight aneurysms (80%). In-stent stenosis was observed in one patient whereas two patients showed de novo stenosis in one of the efferent branches.

CONCLUSIONS

This early experience on the use of the pCONUS HPC device suggests that it can be useful for treating unruptured WNBA under ASA as SAPT. Further investigation with a randomised treatment registry and larger cohort is needed.

Follow-up outcomes of intracranial aneurysms treated using braided or laser-cut stents with closed-cell design: a propensity score-matched case-controlled comparison

BACKGROUND

The impact of various stents on patients with intracranial aneurysms who undergo stent-assisted coiling has been debated. We conducted this study to compare follow-up outcomes of coiling procedures involving braided or laser-cut stents with closed-cell design. A propensity score-matched case-controlled analysis was applied.

METHODS

A total of 413 intracranial aneurysms consecutively coiled using laser-cut (n=245) or braided stents (n=168) in procedures performed between September 2012 and June 2017 were eligible for study. Time-of-flight magnetic resonance angiography, catheter angiography, or both were used to gauge occlusive status after coiling. Recanalization was determined by Raymond classification (complete occlusion vs recanalization). A propensity score-matched analysis was conducted, based on probability of stent type in use.

RESULTS

Ultimately, 93 coiled aneurysms (22.5%) showed some recanalization (minor, 51; major, 42) during the follow-up period (mean 21.7±14.5 months). Patient gender (P=0.042), hyperlipidemia (P=0.015), size of aneurysm (P=0.004), neck size (P<0.001), type of aneurysm (P<0.001), and packing density (P=0.024) differed significantly by group. Midterm and cumulative recanalization incidence rates in the braided-stent group were initially lower than those of the laser-cut stent group (P=0.009 and P=0.037, respectively) but they did not differ significantly after 1:1 propensity score matching (midterm OR=0.88, P=0.724; cumulative HR=0.91, P=0.758).

CONCLUSION

In stent-assisted coiling of intracranial aneurysms, laser-cut and braided stent groups produced similar outcomes in follow-up. Consequently, product selection may hinge on suitability for deployment rather than anticipated results.

Stent-assisted coil embolization of unruptured middle cerebral artery aneurysms using LVIS Jr. stents

Authors reported the anatomical and clinical results of the stent assisted coiling (SAC) of unruptured middle cerebral artery (MCA) aneurysms using Low-profile Visualized Intraluminal Support Junior (LVIS Jr.). Forty-seven MCA aneurysms in 46 patients were the subjects of this study. The mean aneurysm size, neck width were 4.5 ± 1.8 mm, 3.0 ± 1.0 mm, respectively. Immediate anatomical outcomes were class Ⅰ in 31 (65.0%), class Ⅱ in 5 (10.6%) and class III in 11 (23.4%) patients according to Raymond-Roy classification. The latest anatomical outcomes were class Ⅰ in 33 (86.8%), class Ⅱ in 2 (5.3%) and class III in 3 (7.9%) patients. The change of aneurysm obliteration status were unchanged in 27 (71.0%), improved in 9 (23.7%) and worsen in 2 (5.3%). There were no recurrence necessitating additional treatment. Two patients suffered from angiographically evident in-stent thrombosis, but their clinical outcomes remain good. The modified Rankin scale at discharge were 0 in 45 patients, 1 in 1 patient. No patient showed clinical worsening during the clinical follow-up period at outpatient clinic (mean, 27.4 months). SAC of unruptured MCA aneurysms using LVIS Jr. provide safe and durable effect with high complete obliteration rate recurrence rate.

Tailored antiplatelet agent medication in clopidogrel hyporesponsive patients before stent-assisted coiling: single-center experience

PURPOSE

In patients requiring stent procedures, resistance or hyperresponsiveness to antiplatelet medications is often observed. This study aims to evaluate the efficacy and safety of tailoring medications in these patients.

METHODS

This retrospective study included 223 patients who underwent endovascular treatment for intracranial aneurysm between October 2018 and October 2019. Patients were categorized as hyporesponsive, hyperresponsive, and normoresponsive groups according to the initial PRU response. For the hypo- or hyperresponders, we tailored medication by modifying the dose or changing the drug. PRUs before and after tailoring were compared in each group. PRU reponses in patients who underwent Cytochrome P450 2C19 (CYP2C19) genotyping were also determined.

RESULTS

Of the 73 clopidogrel-resistant patients, the mean PRU values after tailoring showed a greater decrease in the group that switched to prasugrel (n = 56), from 223 to 131, than in the clopidogrel reloading group (n = 17), from 238 to 209. In 31 hyperresponders, PRU increased from 49 to 94 after the dose adjustment. CYP2C19 genotyping showed that PRU tended to increase as the number of mutated alleles increased. There were five (2.3%) ischemic events (three transient ischemic attacks and two minor strokes) in a mean follow-up of 8 months, but no hemorrhage.

CONCLUSIONS

The stent-assisted coiling was successfully performed with acceptable range of ischemic events and without hemorrhage in all patients, including those who applied tailored medication. Low-dose prasugrel was effective for obtaining appropriate PRU values for initial medication as well as for clopidogrel-resistant patients. The genetic test did not provide reliable results in determining clopidogrel resistance.

Thromboembolism during coiling of intracranial aneurysms: predictors and clinical outcome

Introduction

Thromboembolism is one of the most serious complications associated with coil embolization therapy.

Aim

To identify predisposing factors for thromboembolic complications, as well as to determine whether thromboembolism has an impact on clinical outcome.

Material and methods

From February 2008 to March 2015, 273 consecutive patients were treated at our institution via endovascular coil embolization. Patient medical records were reviewed with an emphasis on procedure description, potential risk factors and clinical outcomes related to thromboembolism. Thromboembolic incidents occurred in 19 (6.9%) cases. Multivariate logistic regression models were used to determine independent predictors of thromboembolism. Clinical outcome was analyzed using the Glasgow Outcome Scale (GOS).

Results

Multivariate analysis showed that subarachnoid hemorrhage was an independent risk factor for thromboembolic complications (p = 0.003; OR = 4.4; 95% CI: 1.67–12.02). The difference in frequency of perioperative mortality (GOS 1) in patients with thromboembolism and without thromboembolism was not statistically significant (p = 0.22). The differences in frequencies of severe disability (GOS 2–3) and moderate to low disability (GOS 4–5) between patients with thromboembolism and without thromboembolism were statistically significant in the general study population (p < 0.05).

Conclusions

Subarachnoid hemorrhage is an independent predictor of thromboembolic complications associated with endovascular coiling of cerebral aneurysms. Thromboembolism is associated with significantly increased risk of morbidity, and it affects to a certain extent the periprocedural mortality.

[Endovascular Treatment of Cerebral Aneurysms: Technical Options in Coil Embolization]

Since the endosaccular coil embolization technique was introduced as an alternative for treating selected patients with aneurysms, it has become a mainstay of treatment for cerebral aneurysms. In lesions with a neck larger than the aneurysmal body, an irregular shape, or arterial branches incorporated within the sac, endovascular treatment using detachable coils are traditionally contraindicated because of technical difficulties. Coil embolization has evolved as a result of both the development of related devices and the introduction of technical improvements using various devices. Use of various technical and device options can make endovascular treatment of cerebral aneurysms safer and can widen the treatment indications. Various technical options, including the technical modification of device-assisted techniques, will be presented, and the related practical points will be discussed in this issue.

Anti-thrombogenic coatings for devices in neurointerventional surgery: Case report and review of the literature

BACKGROUND

Stent-assisted coiling and extra-saccular flow diversion require dual anti-platelet therapy due to the thrombogenic properties of the implants. While both methods are widely accepted, thromboembolic complications and the detrimental effects of dual anti-platelet therapy remain a concern. Anti-thrombogenic surface coatings aim to solve both of these issues. Current developments are discussed within the framework of an actual clinical case.

CASE DESCRIPTION

A 33-year-old male patient lost consciousness while doing sport and was administered 500 mg acetylsalicylic acid on site. Computed tomography revealed a massive subarachnoid haemorrhage, and digital subtraction angiography showed an aneurysm of the right middle cerebral artery. Stent-assisted coiling using a neck bridging device with a hydrophilic coating (pCONUS_HPC) was considered as an appropriate approach. Another 500 mg acetylsalicylic acid IV was given. After the single anti-platelet therapy was seen to be effective, a pCONUS_HPC was implanted, and the aneurysm sac subsequently fully occluded using coils. No thrombus formation was encountered. During the following days, 2 × 500 mg acetylsalicylic acid IV daily were required to maintain single anti-platelet therapy, monitored by frequent response testing. Follow-up digital subtraction angiography after 13 days confirmed the occlusion of the aneurysm and the patency of the middle cerebral artery.

CONCLUSION

A variety of ways to reduce the thrombogenicity of neurovascular stents is discussed. Hydrophilic surface coatings are a valid concept to improve the haemocompatibility of neurovascular implants while avoiding the use of dual anti-platelet therapy. Phosphorylcholine and phenox hydrophilic polymer coating are currently the most promising candidates. This concept is supported by anecdotal experience. However, formalised registries and randomised trials are currently being established.

Comparison of Prasugrel and Clopidogrel Used as Antiplatelet Medication for Endovascular Treatment of Unruptured Intracranial Aneurysms: A Meta-Analysis

BACKGROUND

Clopidogrel is routinely used to decrease ischemic complications during neurointerventional procedures. However, the efficacy may be limited by antiplatelet resistance.

PURPOSE

Our aim was to analyze the efficacy of prasugrel compared with clopidogrel in the cerebrovascular field.

DATA SOURCES

A systematic search of 2 large databases was performed for studies published from 2000 to 2018.

STUDY SELECTION

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies reporting treatment-related outcomes of patients undergoing neurointerventional procedures under prasugrel, and studies comparing prasugrel and clopidogrel.

DATA ANALYSIS

Random-effects meta-analysis was used to pool the overall rate of complications, ischemic and hemorrhagic events, and influence of the dose of prasugrel.

DATA SYNTHESIS

In the 7 included studies, 682 and 672 unruptured intracranial aneurysms were treated under prasugrel (cases) and clopidogrel (controls), respectively. Low-dose (20 mg/5 mg; loading and maintenance doses) prasugrel compared with the standard dose of clopidogrel (300 mg/75 mg) showed a significant reduction in the complication rate (OR = 0.36; 95% CI, 0.17-74, P = .006; I² = 0%). Overall, the ischemic complication rate was significantly higher in the clopidogrel group (40/672 = 6%; 95% CI, 3%-13%; I² = 83% versus 16/682 = 2%; 95% CI, 1%-5%; I² = 73%; P = .03). Low and high loading doses of prasugrel were associated with 0.6% (5/535; 95% CI, 0.1%-1.6%; I² = 0%) and 9.3% (13/147; 95% CI, 0.2%-18%; I² = 60%) intraperiprocedural hemorrhages, respectively (P = .001), whereas low and high maintenance doses of prasugrel were associated with 0% (0/433) and 0.9% (2/249; 95% CI, 0.3%-2%; I² = 0%) delayed hemorrhagic events, respectively (P = .001).

LIMITATIONS

Retrospective series and heterogeneous endovascular treatments were limitations.

CONCLUSIONS

In our study, low-dose prasugrel compared with clopidogrel premedication was associated with an effective reduction of the ischemic events with an acceptable rate of hemorrhagic complications.

Periprocedural Neuroendovascular Antiplatelet Strategies for Thrombosis Prevention in Clopidogrel-Hyporesponsive Patients

Patients undergoing neuroendovascular procedures such as cerebral aneurysm coiling and intracranial stent deployment are frequently treated with antiplatelet agents to prevent thrombotic complications. The combination of aspirin and a P2Y12 inhibitor such as clopidogrel is often initiated days before elective procedures or as loading doses for emergent procedures; however, some patients may still experience thrombotic complications. Patients identified as clopidogrel hyporesponders are more likely to experience poor outcomes and may require changes to their regimens. Historically, high-dose clopidogrel regimens were used in response to subtherapeutic results of platelet function assays and point-of-care testing despite limited supporting data. Recently, more data have emerged using alternative P2Y12 inhibitors such as prasugrel and ticagrelor. Dosing for neuroendovascular conditions is often extrapolated from the cardiac literature, although outcomes in cardiac patients may not be relevant to neurologic patients, making prophylactic treatment recommendations challenging for these patients. This review summarizes the literature for antiplatelet prophylaxis in patients undergoing neuroendovascular device placement, focusing on alternative regimens for clopidogrel hyporesponders.

Safety and efficacy of anterior communicating artery compromise during endovascular coil embolization of adjoining aneurysms

OBJECTIVE

In the presence of symmetric A1 flow, the safety and efficacy of compromising the anterior communicating artery (ACoA) during coil embolization of ACoA aneurysms has yet to be evaluated. Herein, the authors describe their experience, focusing on procedural safety.

METHODS

Between October 2012 and July 2017, 285 ACoA aneurysms with symmetric A1 flows were treated at the authors' institution by endovascular coil embolization. Clinical and angiographic outcome data were subjected to binary logistic regression analysis.

RESULTS

ACoA compromise was chosen in the treatment of 71 aneurysms (24.9%), which were completely (n = 15) or incompletely (n = 56) compromised. In the remaining 214 lesions, the ACoA was preserved. Although 9 patients (3.2%) experienced procedure-related thromboembolisms (compromised, 4; preserved, 5), all but 1 patient (with ACoA compromise) were asymptomatic. In multivariate analysis, subarachnoid hemorrhage at presentation was the sole independent risk factor for thromboembolism (OR 15.98, p < 0.01), with ACoA compromise being statistically unrelated. In 276 aneurysms (96.8%) with follow-up of > 6 months (mean 20.9 ± 13.1 months, range 6-54 months), recanalization was confirmed in 21 (minor, 15; major, 6). A narrow (≤ 4 mm) saccular neck (p < 0.01) and ACoA compromise (p = 0.04) were independently linked to prevention of recanalization.

CONCLUSIONS

During coil embolization of ACoA aneurysms, the ACoA may be compromised without serious complications if A1 flows are symmetric. This approach may also confer some long-term protection from recanalization, serving as a valid treatment option for such lesions.

Comparative analysis of coil embolization in posterior and anterior communicating artery aneurysms

Background

Recanalization rates after coil embolization are known to be higher in cerebral aneurysms of the posterior (vs anterior) circulation. Although often grouped with anterior lesions, aneurysms of the posterior communicating artery (PcoA) may nevertheless behave differently.

Objective

We performed a comparative analysis to explore differences in recanalization rates of PcoA and anterior communicating artery (AcoA) aneurysms, both integral to the circle of Willis.

Methods

Between October 2012 and July 2017, 699 AcoA (n=427) and PcoA (n=272) aneurysms were treated by endovascular coil embolization, monitoring 667 (95.4%) via radiologic imaging for ≥ 6 months. Cumulative recordings of medical and imaging data were retrospectively reviewed, conducting propensity score matching and binary logistic regression analysis.

Results

In the 667 aneurysms followed longer term, recanalization occurred in 111 (16.6%; minor 72; major 39) and was significantly more frequent in PcoA (25.5%) than in AcoA (11.0%; P<0.01) aneurysms during similar follow-up periods. After 1:1 propensity score matching, an even greater proclivity for recanalization was evident at PcoA sites (PcoA 23.0%; AcoA 12.2%; P<0.01). Although A1 segment dominance was linked to recanalization in AcoA aneurysms (18.2% vs 7.6%; P=0.01), the PcoA counterpart had no bearing on recanalization (27.7% vs 24.1%; P=0.51).

Conclusions

Despite a clear preponderance of AcoA aneurysms, recanalization of PcoA aneurysms proved significantly greater, attesting to posterior circulation behavior.

Selective Temporary Stent-Assisted Coil Embolization for Intracranial Wide-Necked Small Aneurysms Using Solitaire AB Retrievable Stent

Objective

Stent-assisted coil embolization of intracranial wide-necked aneurysm requires long-term postoperative antiplatelet therapy to prevent in-stent thrombosis. This study aimed to demonstrate results of temporary stent placement for coiling wide necked small intracranial aneurysms, which eliminated need for antiplatelet agents, and to discuss its feasibility and safety.

Methods

Data of 156 patients who underwent stent-assisted coil embolization between 2011 and 2014 were retrospectively analyzed. Thirteen cases of temporary stent-assisted coil embolization were included, and their clinical and radiological results were evaluated.

Results

The aneurysms treated were all unruptured except one case. All of them had wide neck with mean dome-to-neck ratio of 0.96 and were small-sized aneurysms with mean maximal diameter of 4.2 mm. There was no technical failure in retrieval of stent after completion of embolization of the target aneurysm. Immediate angiography revealed 11 complete and two partial embolization (one residual neck and one residual aneurysm). Two cases encountered thrombosis complication, and they were managed without neurological sequelae. The mean follow-up period was 43 months, angiographic follow-up revealed two cases with minor recurrence, and clinical outcome was good with modified Rankin scale score of 0.

Conclusion

Temporary stent-assisted coil embolization of small wide-necked intracranial aneurysm using fully retrievable stent appears safe and effective. Further application and evaluation of this technique in more cases with larger size aneurysm is warranted.

Efficacy and safety of prasugrel therapy for intracranial aneurysms with endovascular treatment: A meta-analysis

BACKGROUND

Prasugrel as a second generation P2Y12 adenosine diphosphate receptor antagonist which in the cerebral aneurysms with Endovascular treatment have become more emphasized.

OBJECTIVE

To compare the efficacy and safety of prasugrel therapy for intracranial aneurysms with endovascular treatment.

METHODS

The databases of PubMed, Embase, Cochrane Library databases and China Biology Medicine disc were retrieved with computers for collecting controlled trials about the comparison in the efficacy and safety of prasugrel and clopidogrel published from inception to September 2018. At the same time, the reference materials of included literature were retrieved manually. After rigorous evaluation on literature quality, the eligible data of the trials was extracted and given a Meta-analysis by applying RevMan5.3 software.

RESULTS

Of the 96 studies identified, 7 trials were included. Results of meta-analysis showed that compared with patients receiving clopidogrel treatment, novel platelet P2Y₁₂ receptor inhibitor prasugrel were effective in reducing the incidence of thromboembolic events (OR = 0.19, 95%CI: 0.08-0.45, P = .0001), but did not increase the risk of hemorrhagic complication (OR = 1.00, 95%CI: 0.53-1.89, P = 1.00), and the PRU (OR = 0.19, 95%CI: 0.08-0.45, P = .0001) and Percentage inhibition of platelet (MN = 37.05, 95%CI: 33.37-40.73, P < .00001) were controlled in a better range.

CONCLUSION

In antiplatelet therapy after aneurysmal interventional therapy, the second generation of P2Y₁₂ adenosine receptor antagonist prasugrel can significantly reduce the risk of thrombosis without increasing the risk of bleeding.

Variability of Platelet Reactivity on Antiplatelet Therapy in Neurointervention Procedure

As more intracranial aneurysms and other cerebrovascular pathologies are treated with neurointervention procedure, thromboembolic events that frequently lead to serious neurological deficit or fatal outcomes are increasing. In order to prevent the thromboembolic events, antiplatelet therapy is used in most procedures including coil embolization, stenting, and flow diversion. However, because of variable individual pharmacodynamics responses to antiplatelet drugs, especially clopidogrel, it is difficult for clinicians to select the adequate antiplatelet regimen and its optimal dose. This article reviews the neurointervention literature related to antiplatelet therapy and suggests a strategy for tailoring antiplatelet therapy in individual patients undergoing neurointervention based on the results of platelet function testing.

Use of Antiplatelet Agents in the Neurosurgical Patient

Antiplatelet agents used to treat neurovascular disease include aspirin; P2Y12 receptor antagonists clopidogrel, prasugrel, and ticagrelor; ADP antagonist ticlopidine; phosphodiesterase inhibitor dipyridamole; and glycoprotein IIb/IIIa inhibitors abciximab, eptifibatide, and tirofiban. Numerous studies have been performed evaluating their efficacy in stroke, extracranial carotid artery disease and dissection, intracranial atherosclerotic disease, and moyamoya disease. The rapid technological advancements in endovascular neurosurgical devices have also made antiplatelet therapy a necessary part of treating intracranial aneurysms. This article presents the relevant data supporting the use of antiplatelet agents in vascular neurosurgery and recommendations based on the described studies.

Selective compromise of hypoplastic posterior communicating artery variants with aneurysms treatable by coil embolization: clinical and radiologic outcomes

Background

Posterior communicating artery (PcoA) compromise may serve as adjunctive treatment in patients with hypoplastic variants of PcoA who undergo coil embolization of PcoA aneurysms. However, procedural safety and the propensity for later recanalization are still unclear.

Objective

To evaluate clinical and radiologic outcomes of coil embolization in this setting, focusing on compromise of PcoA.

Methods

As a retrospective review, we examined 250 patients harboring 291 aneurysms of hypoplastic PcoAs, all consecutively treated by coil embolization between January 2004 and June 2016. PcoA compromise was undertaken in conjunction with 81 of the treated aneurysms (27.8%; incomplete 53; complete 28). Medical records and radiologic data were assessed during extended monitoring.

Results

During the mean follow-up of 33.9±24.6 months (median 36 months), a total of 107 (36.8%) coiled aneurysms showed recanalization (minor 50; major 57). Recanalization rates were as follows: PcoA preservation 40.5% (85/210); incomplete PcoA occlusion 34.0% (18/53); complete PcoA occlusion 14.3% (4/28). Aneurysms >7 mm (HR 3.40; P<0.01), retreatment for recanalization (HR 3.23; P<0.01), and compromise of PcoA (P<0.01) emerged from multivariate analysis as significant risk factors for recanalization. Compared with PcoA preservation, complete PcoA compromise conferred more favorable outcomes (HR 0.160), whereas incomplete compromise of PcoA fell short of statistical significance. Thromboembolic infarction related to PcoA compromise did not occur in any patient.

Conclusion

PcoA compromise in conjunction with coil embolization of PcoA aneurysms appears safe in hypoplastic variants of PcoA, helping to prevent recanalization if complete occlusion is achieved.

Postoperative Anticoagulation After Neurologic Surgery

Management of anticoagulation and antiplatelet medications after neurosurgery can be complex, especially given that these patients have multiple medical comorbidities. In turn, neurosurgical patients are at high risk for the development of venous thromboembolism after surgery, so neurosurgeons must consider the use of pharmacologic prophylaxis. Developments in endovascular neurosurgery have produced therapies that require close management of antiplatelet medications to prevent postoperative complications. Any of these patient populations may need intrathecal access. This article highlights current strategies for managing these issues in the neurosurgical patient population.

Low-Dose Prasugrel in Patients with Resistance to Clopidogrel for the Treatment of Cerebral Aneurysms

Thromboembolism is one of the major complications of stent assisted coiling in treatment of cerebral aneurysm. Clopidogrel resistance is so common and prasugrel is more effective in its rapid and potent effect. We investigated changes in the value of P2Y12 resistance unit (PRU) when prasugrel was administered to patients with clopidogrel resistance. One hundred mg of aspirin and 75 mg of clopidogrel were administered for 5 days before the procedure, and PRU were examined. The resistance to clopidogrel was defined as the inhibition of PRU was less than 20%. PRU was re-examined after loading 20 mg of prasugrel. We treated 98 consecutive patients between January 2018 and July 2018, and 24 patients (24.5%) had resistance to clopidogrel. Nineteen patients were female. The mean PRU value at admission was 238.5±36.9 and the percentage inhibition value was 4.8±6.3%. After the use of prasugrel, the mean PRU and percentage inhibition values were measured as 124.9±49.9 and 48.0±19.24, respectively. All patients except one patient had a PRU inhibition value as a responder. There was no hemorrhage or thromboembolic complication during mean 1.5 months follow-up after embolization procedure. In conclusion, in patients resistant to clopidogrel, the low dose prasugrel seems to be effective in keeping the percentage inhibition value of PRU within the normal range in treatment of cerebral aneurysm. Further study will be needed to determine the optimal dose of prasugrel to enhance prevention effect of thromboembolism and to reduce hemorrhagic complications during stent assisted coiling.