Insufficient platelet inhibition and thromboembolic complications in patients with intracranial aneurysms after stent placement

Prophylactic administration of tirofiban prevents ischemic events in endovascular treatment of unruptured intracranial aneurysms

BACKGROUND

Stents-assisted coiling (SAC) and flow diverters (FD) are widely used in the endovascular treatment of intracranial aneurysms. However, due to the thrombogenicity of metallic implants, their application may increase the risk of ischemic events. This study aims to evaluate the efficacy of prophylactic tirofiban with dual antiplatelet treatment (DAPT) in unruptured intracranial aneurysms (UIA) patients treated with SAC or FD.

METHODS

This single center retrospective study included patients with UIAs treated with SAC or FD. Data collected included demographic information, imaging findings, laboratory results, and perioperative complications. Multivariate logistic regression analysis was used to identify independent risk factors for ischemic events. Patients were stratified based on these risk factors, and the efficacy of tirofiban was evaluated across different risk groups.

RESULTS

A total of 420 patients were included in the study, of whom 22(5.2%) experienced ischemic events. Among them, eight patients (3.3%) were in the tirofiban group and 14 patients (8.0%) were in the DAPT (non-tirofiban) group. Multivariate logistic regression identified independent risk factors for ischemic events, including posterior circulation aneurysm (OR: 2.87, 95% CI: 1.06-7.78; P = 0.038) and diabetes (OR: 4.05, 95% CI: 1.50-10.96; P = 0.006). The prophylactic use of tirofiban combined with DAPT can effectively reduce postoperative ischemic events (OR: 0.35, 95% CI: 0.14-0.91; P = 0.032) without increasing the risk of hemorrhage.

CONCLUSION

This study demonstrates that prophylactic use of tirofiban can effectively reduce postoperative ischemic events in UIA patients receiving SAC or FD treatments without increasing the risk of hemorrhage.

Platelet aggregation rate serves as a significant predictive indicator for thromboembolic events in the context of stent-assisted embolization for unruptured arterial aneurysms

Background

Perioperative cerebrovascular thromboembolic events are serious complications of stent-assisted embolization (SAE) for unruptured intracranial aneurysms (UIAs). To date, there have been no definitive clinical trial results to effectively predict and prevent the occurrence of this complication. This study aims to elucidate the correlation between platelet aggregation rate (PAR) and thromboembolic events (TEs), with the goal of predicting the occurrence of cerebrovascular TEs in these patients.

Methods

In this retrospective, single-center cohort study, we included 704 cases of unruptured intracranial aneurysms treated with stent-assisted intervention from 2016 to 2020. Cerebrovascular TEs were defined as cerebral ischemic events occurring within 7 days before or after the interventional procedure. Light Transmission Aggregometry (LTA) was used to detect PAR in patients. Clinical data, including patients' demographic information and perioperative PAR, were collected. Multivariate analysis was conducted to examine the correlation between these factors and the occurrence of TEs. Additionally, Lasso regression was employed to select clinical indicators associated with perioperative TEs. Receiver Operating Characteristic (ROC) curves were generated for prognostic indicators such as PAR, with the optimal cutoff value determined. A nomogram was then simulated, and predictive accuracy of the model was evaluated using Decision Curve Analysis (DCA).

Results

A total of 562 patients were included in the final analysis. Significant differences were observed in the incidence of thrombosis between the control group and the experimental group (9.38% vs. 4.96%). The ROC curve of platelet aggregation index, highly correlated with prognosis and derived from Lasso regression, identified the optimal cutoff value for the maximum preoperative PAR as 19.81. A nomogram was constructed based on selected clinical baseline data, and its calibration was assessed using data from the prediction group. The net benefit of the experimental group model's DCA curve was significantly improved.

Conclusion

For patients undergoing SAE for UIAs, utilizing PAR and other indicators as reference standards for treatment results in better prognosis compared to empirical treatment based on guidelines. Guiding antiplatelet therapy using PAR and other indicators is both meaningful and beneficial to clinical practice.

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.

Guided Antiplatelet Therapy for Stent-Treated Intracranial Aneurysms: A Cluster-Randomized Trial

Background During neurointerventional treatment of intracranial aneurysms (IAs), poor antiplatelet drug response increases the risk of a cerebral ischemic event (IE). Replacing clopidogrel with ticagrelor may reduce this risk. Purpose To determine whether platelet function test (PFT)-guided antiplatelet therapy reduces incidence of IEs compared with standard dual antiplatelet therapy (SDAT; daily oral aspirin and clopidogrel, 100 mg and 75 mg, respectively) in patients undergoing endovascular intervention for IAs. Materials and Methods In this prospective, multicenter, cluster-randomized trial, 16 neurointerventional teams were randomly allocated to eight test and eight control clusters. Between May and August 2023, test group participants underwent PFT. Test group participants who showed poor antiplatelet response were administered an increased aspirin dose or were switched from clopidogrel to ticagrelor. The control group was administered SDAT. The primary outcome was any cerebral IE within 30 days after the procedure. The exploratory outcomes were any IE within 7 days, modified Rankin Scale score, and all-cause mortality within 30 days. The safety outcome measure was any bleeding event within 30 days. All outcome analyses were performed using generalized linear mixed-effects models. Results A total of 590 participants were included (median age, 58 years; 374 women). IE incidence within 30 days was lower in the test group than in the control group (6.8% [20 of 295] vs 13.2% [39 of 295]; odds ratio [OR], 0.54; 95% CI: 0.31, 0.94; P = .03) and within 7 days (4.1% [12 of 295] vs 10.8% [32 of 295]; OR, 0.48; 95% CI: 0.25, 0.89; P = .02) after undergoing the procedure. There was no evidence of a difference between the test group and the control group in modified Rankin Scale scores (0.33 vs 0.49, respectively; P = .11) or mortality (0.3% [one of 295] vs 2.0% [six of 295], respectively; P = .54). Furthermore, there was no evidence of a between-group difference in bleeding event incidence (24.1% [71 of 295] vs 31.2% [92 of 295]; OR, 0.67; 95% CI: 0.30, 1.5; P = .32). Conclusion PFT-guided antiplatelet therapy was associated with reduced IE incidence. Administration of 60 mg of ticagrelor did not increase bleeding event incidence. Clinicaltrials.gov Identifier: NCT05825391 © RSNA, 2025 Supplemental material is available for this article. See also the editorial by Kallmes and Altschul in this issue.

Analysis of the effect of platelet function and different doses of ticagrelor after flow diverter treatment of intracranial aneurysms

Ticagrelor has become the standard drug for the treatment of intracranial aneurysms (IAs) with flow diverters (FDs), but the dosage has not been standardized. The effect of platelet function on clinical and imaging prognosis remains unclear. This study aimed to show the effects of different doses of ticagrelor and platelet aggregation function on the clinical and imaging prognosis after FDs treatment of aneurysms. Patients with IAs and underwent FDs stenting were recruited between July 2019 and June 2023. Logistic regression was performed to assess the predictors of incomplete occlusion and in-stent stenosis (ISS). Linear regression analysis, scatter plot and violin diagram were used to investigate the predictors of maximum platelet aggregation rate induced by ADP (ADP-MPA). The study included 156 patients with 206 aneurysms. There was no significant difference in clinical prognosis and aneurysm occlusion rates between the standard-dose group (ticagrelor, 90 mg/bid) and the low-dose group (ticagrelor, 45 mg/bid). Multivariable analysis identified the ADP-MPA ≥ ADP-MPA (median) (24.2%) (p = 0.037) as an independent risk factor for incomplete occlusion of aneurysms. In addition, higher ADP-MPA (p = 0.045) was an independent risk factor for ISS. Uric acid level (p = 0.019) was negatively associated with ADP-MPA, whereas age (p = 0.031) and body mass index (BMI) (p = 0.042) were positively associated with ADP-MPA. The differences of clinical prognosis and aneurysm occlusion rates between the standard-dose group and the low-dose group were not significant for the treatment of aneurysms with FDs. Higher ADP-MPA predicted higher rates of incomplete occlusion and in-stent stenosis. Uric acid level was negatively associated with ADP-MPA, whereas age and BMI were positively associated with ADP-MPA.

Recanalization of a chronic occlusion flow-diverter device in a patient with a paraclinoid giant aneurysm recurrence. Clinical observation

Paraclinoid internal carotid artery (ICA) aneurysms are associated with a high mortality rate, which gradually increases without intervention. Surgical clipping or coiling of large aneurysms with inadequate neck and adductor artery expansion will not guarantee a successful outcome. Carotid surgical trapping or endovascular occlusion of the adductor artery can help to isolate the aneurysm from circulation, but it comes at the expense of sacrificing a major blood vessel responsible for significant cerebral perfusion. Currently, a technique has been developed to redirect blood flow and stimulate gradual thrombosis in the aneurysm cavity to reduce pressure on its walls. However, in cases of recurrent aneurysm and stent thrombosis in these patients, it is necessary to consider destructive surgery. The 65-year-old patient, who had a history of migraine, was diagnosed with a large aneurysm. He was initially treated with the Pipeline Flex stent from Medtronic, but after 5 months, he experienced 2 transient ischemic attacks. Subsequent CT scans revealed no signs of brain damage, but a brain CTA revealed the recurrence of an internal carotid artery paraclinoid aneurysm with the occlusion of the pipeline device and contrast flowing parallel to the aneurysm wall. This case is an example of successful recanalization of an occluded flow diverter device in a patient with recurrent internal carotid aneurysm.

Prevalence of Risk Factors in Patients with Postprocedural Ischemic Lesions after Coiling of Very Small Intracranial Aneurysms

Background: Very small intracranial aneurysms, generally considered to be those 3 mm in diameter or smaller, pose particular technical challenges for endovascular surgeons. For this reason, very small aneurysms have been excluded from many relevant studies. The aim of our research was to establish the risk factors for the occurrence of stroke complications after endovascular embolization of ruptured and unruptured small intracranial aneurysms. Methods: During the period of 2009-2023, our team performed endovascular embolizations of intracranial aneurysms in 1567 patients across four different centers within the territory of Serbia and Montenegro. Within the total number of patients mentioned, aneurysms of less than 4 mm were treated 185 times, with 119 ruptured and 66 unruptured. Results: In the group of 119 patients with ruptured small intracranial aneurysms, 19 (16%) patients had ischemia after the endovascular treatment, 6 (5%) patients had minor neurological deficits, while 13 (10.9%) patients had major neurological deficits, of which 6 (5%) patients died. In the group of 66 patients with unruptured small intracranial aneurysms, 7 (10.6%) patients had ischemia after the endovascular treatment, 5 (7.6%) patients had minor neurological deficits, and 2 (3.03%) had major neurological deficits. Multivariate binary logistic regression showed that the risk factors for the occurrence of ischemia were the patient's age, smoking and alcohol consumption. The type of endovascular treatment used also had a statistically significant effect on the development of ischemia. Conclusions: Understanding the influence of possible risk factors for the occurrence of ischemic insult after embolization of small intracranial aneurysms is of great importance. By recognizing them, periprocedural complications can be reduced to a minimum.

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.

Short- versus long-term Dual AntiPlatelet Therapy for Stent-Assisted treatment of CErebral aneurysm (DAPTS ACE): a multicenter, open-label, randomized clinical trial

BACKGROUND

The optimal duration of dual antiplatelet therapy (DAPT) after stent-assisted coil embolization (SACE) for cerebral aneurysm remains uncertain. This randomized trial of short- versus long-term Dual AntiPlatelet Therapy for Stent-Assisted treatment of CErebral aneurysm (DAPTS ACE) aimed to clarify whether long-term DAPT can reduce the occurrence of ischemic stroke in patients with cerebral aneurysms treated by SACE compared with short-term DAPT.

METHODS

Patients treated for cerebral aneurysm with SACE were enrolled from 17 hospitals in Japan. Patients were enrolled within 30 days after SACE and assigned in a 1:1 ratio to receive long-term (12 months) or short-term (3 months) DAPT with aspirin and clopidogrel. Randomization was performed centrally through a web-based system. The primary outcome was the time to ischemic stroke event during 3 to 12 months after SACE. This trial was registered with the Japan Registry of Clinical Trials (jRCTs051180141).

RESULTS

A total of 142 patients were recruited from November 4, 2016 to January 7, 2019. Among them, 65 and 68 patients assigned to the long- and short-term DAPT groups, respectively, were included in the full analysis set. Ischemic stroke occurred in no patients in the long-term DAPT group and in one patient in the short-term DAPT group. The incidence rate did not differ between the groups (0.0 vs 2.1/100 person-years; log rank test, P=0.33).

CONCLUSIONS

In this multicenter randomized controlled trial, there was not a statistically significant difference in the rate of ischemic strokes between long- and short-term DAPT.

Effect of Platelet Function Testing Guidance on Clinical Outcomes for Patients with Intracranial Aneurysms Undergoing Endovascular Treatment

BACKGROUND

Platelet function testing has been proposed to better adjust individualized antiplatelet treatment for patients undergoing endovascular treatment for intracranial aneurysms. Its clinical significance needs to be comprehensively evaluated.

PURPOSE

Our aim was to evaluate the impact of platelet function testing-guided versus standard antiplatelet treatment in patients receiving endovascular treatment for intracranial aneurysms.

DATA SOURCES

PubMed, EMBASE, and the Cochrane Library of clinical trials were searched from inception until March 2023.

STUDY SELECTION

Eleven studies comprising 6199 patients were included.

DATA ANALYSIS

ORs with 95% CIs were calculated using random effects models.

DATA SYNTHESIS

The platelet function testing-guided group was associated with a decreased rate of symptomatic thromboembolic events (OR = 0.57; 95% CI, 0.42-0.76; I2 = 26%). No significant difference was found in asymptomatic thromboembolic events (OR = 1.07; 95% CI, 0.39-2.94; I2 = 48%), hemorrhagic events (OR = 0.71; 95% CI, 0.42-1.19; I2 = 34%), intracranial hemorrhagic events (OR = 0.61; 95% CI, 0.03-10.79; I2 = 62%), morbidity (OR = 0.53; 95% CI, 0.05-5.72; I2 = 86%), and mortality (OR = 1.96; 95% CI, 0.64-5.97; I2 = 0%) between the 2 groups. Subgroup analysis suggested that platelet function testing-guided therapy may contribute to fewer symptomatic thromboembolic events in patients who received stent-assisted coiling (OR = 0.43; 95% CI, 0.18-1.02; I2 = 43%) or a combination of stent-assisted and flow-diverter stent placement (OR = 0.61; 95% CI, 0.36-1.02; I2 = 0%) or who changed from clopidogrel to other thienopyridines (OR = 0.64; 95% CI, 0.40-1.02; I2 = 18%), though the difference did not reach statistical significance.

LIMITATIONS

Heterogeneous endovascular treatment methods and adjusted antiplatelet regimens were limitations.

CONCLUSIONS

Platelet function testing-guided antiplatelet strategy significantly reduced the incidence of symptomatic thromboembolic events without any increase in the hemorrhagic events for patients undergoing endovascular treatment for intracranial aneurysms.

Antiplatelet therapy adjustment improved the radiomic characteristics of acute silent cerebral infarction after stent-assisted coiling in patients with high on-treatment platelet reactivity: A prospective study

Background

We aimed to investigate the effects of high on-treatment platelet reactivity (HPR) and antiplatelet therapy adjustment on high-risk radiomic features in patients with antiplatelet therapy adjustment on acute silent cerebral infarction (ASCI) who had unruptured intracranial aneurysms (UIA) after stent placement.

Methods

This single-institution study prospectively included 230 UIA patients who had ACSI after stent placement in our hospital between January 2015 and July 2020. All patients underwent magnetic resonance imaging with diffusion-weighted imaging (MRI-DWI) after stent placement and 1,485 radiomic features were extracted from each patient. The least absolute shrinkage and selection operator regression methods were used for selection of high-risk radiomic features associated with clinical symptoms. In addition, 199 patients with ASCI were classified into three groups: controls without HPR (n = 113), HPR patients with standard antiplatelet therapy (n = 63) and HPR patients with antiplatelet therapy adjustment (n = 23). We compared high-risk radiomic features between three groups.

Results

Of the patients who had acute infarction after MRI-DWI, 31 (13.5%) exhibited clinical symptoms. Eight risk radiomic features associated with clinical symptoms were selected, and the radiomics signature exhibited good performance. In ASCI patients, compared with controls, the radiomic characteristics of ischemic lesion in HPR patients were consistent with the following high-risk radiomic features associated with clinical symptoms: higher gray-level values, greater variance in intensity values, and greater homogeneity. However, the adjustment of antiplatelet therapy in HPR patients modified the high-risk radiomic features, which showed lower gray-level values, less variance in intensity values, and more heterogeneous texture. The radiomic shape feature of elongation showed no notable difference between three groups.

Conclusion

Adjustment of antiplatelet therapy might reduce the high-risk radiomic features of UIA patients with HPR after stent placement.

Is it safe to discontinue antiplatelet medication after stent-assisted coil embolization? If so, when is the best time?

PURPOSE

Antiplatelet maintenance after stent-assisted coil embolization (SACE) is generally considered essential to avoid post-procedural thromboembolic complications. However, there is still debate as to whether it is safe to discontinue antiplatelet drugs after SACE or when is the best time to do so. We investigate herein the clinical outcomes experienced by patients who discontinue antiplatelet agents after SACE.

METHODS

From a prospective database, we retrieved the data for 120 consecutive patients (harboring 130 aneurysms) in whom antiplatelet agents were discontinued after SACE between January 2010 and December 2019. We defined thromboembolic complications associated with discontinuation as neurologic or radiographic ischemia that occurred within 6 months of discontinuation of antiplatelet agents; the lesion was required to be correlated with the stented artery.

RESULTS

The mean time of discontinuation of antiplatelet medication was 31.4 ± 18.3 months after SACE (median, 26 months). The majority of patients stopped antiplatelet medication between 18 and 36 months after SACE (74 patients, 61.6%). Laser-cut closed-cell stent was most commonly applied in 91 aneurysms (70.0%), followed by braided closed-cell (n=29; 22.3 %) and laser-cut open-cell stent 10 (7.7 %). No patients experienced cerebral ischemia related to discontinuation of antiplatelet medication.

CONCLUSION

Our preliminary study suggests that it may be safe to discontinue antiplatelet medication after SACE in patients at low risk for ischemia. The optimal time to discontinue might be around 18 to 36 months after SACE. Large cohort-based studies or randomized clinical trials are warranted to confirm these results.

Diffusion-weighted imaging lesions after endovascular treatment of cerebral aneurysms: A network meta-analysis

Background

Thromboembolism is one of the common complications in endovascular treatments including coiling alone, stent-assisted coiling (SAC), balloon-assisted coiling (BAC), and flow-diverting (FD) stents. Such treatments are widely used in intracranial aneurysms (IAs), which usually present as positive lesions in diffusion-weighted imaging (DWI). Whether these adjunctive techniques increase postprocedural DWI-positive lesions after endovascular treatment remains unclear.

Methods

A thorough electronic search for the literature published in English between January 2000 and October 2022 was conducted on PubMed, Medline, and EMBASE. Eighteen studies (3 cohort studies and 15 case-control studies) involving 1,843 patients with unruptured IAs (UIAs) were included. We performed a frequentist framework network meta-analysis (NMA) to compare the rank risks of cerebral thromboembolism of the above four endovascular treatments. The incoherence test was used to analyze the statistical disagreement between direct and indirect evidence. Funnel plots were used to analyze publication bias.

Results

The incidences of DWI lesions in patients who received FD stents, SAC, BAC, and coiling alone were 66.1% (109/165), 37.6% (299/795), 31.1% (236/759), and 25.6% (236/921). The incidence of DWI lesions in patients who received FD stents was higher than that in patients who received SAC [OR: 2.40; 95% CI (1.15, 5.00), P < 0.05], BAC [OR: 2.62; 95% CI (1.19, 5.77), P < 0.05], or coiling alone [OR: 2.77; 95% CI (1.26, 6.07), P < 0.05]. The incoherence test showed preferable consistency in this NMA. No obvious publication bias was found in the funnel plot.

Conclusion

FD stent placement brings more ischemic lesions identified by DWI than any other procedures for patients with UIA. The characteristics of FD stents may result in a high incidence of DWI lesions.

Effect of Adjusted Antiplatelet Therapy on Preventing Ischemic Events After Stenting for Intracranial Aneurysms

BACKGROUND AND PURPOSE

This study tests whether patients with unruptured intracranial aneurysm who underwent stent placement benefitted from platelet function monitoring-guided adjustment of antiplatelet therapy.

METHODS

We conducted a randomized, open-label, parallel group, assessor-blinded trial. Patients with unruptured intracranial aneurysm who underwent stent placement were assigned in a 1:1 ratio to receive either drug adjustment (patients who had high on-treatment platelet reactivity to antiplatelet therapy on the basis of platelet function monitoring [monitoring group]) or conventional therapy (without monitoring and drug adjustment [conventional group]). The second monitoring was performed 14 days after randomization in patients with drug adjustment. The primary outcome was the composite frequency of ischemic stroke, transient ischemic attack, stent thrombosis, urgent revascularization, and cerebrovascular death within 7 days after stent implantation. The safety outcome was the composite frequency of major, minor, or minimal bleeding within 1 month after stent implantation.

RESULTS

In total, 314 patients were included (n=157 per group). The primary combined outcome occurred in 19 patients (12.1%) in the conventional group and 8 patients (5.1%) in the monitoring group (hazard ratio, 0.39 [95% CI, 0.17-0.92]; P=0.03). Ischemic stroke occurred at a lower frequency in the monitoring group compared with that in the conventional group (4.5% versus 12.1%; hazard ratio, 0.34 [95% CI, 0.14-0.83]; P=0.01), which drove the overall primary combined outcome. The safety outcome occurred in the monitoring group (7.0%) and in the conventional group (1.9%; hazard ratio, 3.87 [95% CI, 1.06-14.14]; P=0.03). A significant difference was observed in the frequency of minor or minimal bleeding events between the two groups (monitoring group versus conventional group, 6.4% versus 1.3%; P=0.02) but not in the frequency of major bleeding events between the two groups.

CONCLUSIONS

Platelet function monitoring-guided antiplatelet therapy reduces thromboembolic events in patients with unruptured intracranial aneurysm after stent placement, significantly enhancing minor or minimal bleeding events but not major bleeding events. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03989557.

Ticagrelor versus Clopidogrel in the Dual Antiplatelet Regimen for Intracranial Stenting or Flow-Diverter Treatment for Unruptured Cerebral Aneurysms: A Single-Center Cohort Study

BACKGROUND AND PURPOSE

Ticagrelor is a novel P2Y12 antagonist, and little is known about its efficacy and safety in the endovascular treatment of aneurysms. This study evaluated the efficacy and safety of ticagrelor versus clopidogrel for stent-assisted coiling or flow-diversion treatment in patients with unruptured cerebral aneurysms.

MATERIALS AND METHODS

From November 2003 to February 2019, two hundred one patients (mean age, 57.5 years; 156 women) with 233 unruptured aneurysms underwent stent-assisted coiling or flow-diversion treatment. All patients received antiplatelet therapy of aspirin plus clopidogrel (clopidogrel group, 121 patients with 140 aneurysms) or aspirin plus ticagrelor (ticagrelor group, 80 patients with 93 aneurysms). The clinical and radiologic data in each group were retrospectively reviewed and compared.

RESULTS

Two hundred thirty-six procedures were performed, including stent-assisted coiling (n = 101) and flow diversion (n = 135). At 90 days, the primary outcome-a composite of any stroke and death-occurred in 9.9% of the clopidogrel group and 8.6% of the ticagrelor group (P = .822). Ischemic stroke occurred in 10 (7.0%) of the clopidogrel group and 7 (7.5%) of the ticagrelor group (P > .999). Disabling stroke occurred in 4 (2.8%) in the clopidogrel group and in 4 (4.3%) in the ticagrelor group (P = .716). Ninety-day death occurred in 3 (2.1%) in the clopidogrel group and 1 (1.1%) in the ticagrelor group (P > .999). Any bleeding at 90 days occurred in 13 (9.2%) in the clopidogrel group and 6 (6.5%) in the ticagrelor group (P = .479).

CONCLUSIONS

Ticagrelor appears to be as effective and safe as clopidogrel in stent-assisted coiling or flow-diversion treatment for unruptured cerebral aneurysms.

Risk factors for periprocedural ischemic stroke following endovascular treatment of intracranial aneurysms

Background

The aim of this study was to comprehensively evaluate the risk factors of periprocedural ischemic stroke associated with endovascular treatment of intracranial aneurysms using a real-world database.

Methods

From August 2016 to March 2017, 167 patients were enrolled. Univariate analysis and multivariate logistic regression analysis were used to examine the risk factors for periprocedural ischemic stroke.

Results

Among the 167 cases, periprocedural ischemic stroke occurred in 20 cases (11.98%). After univariate analysis, the ischemic group had a higher proportion of large (≥ 10 mm) aneurysms than the control group (45.0% vs. 23.1%, p = 0.036). The incidence of periprocedural ischemic stroke was higher in cases treated by flow diverter (21.6%) or stent-assisted coiling (11.8%) than in cases treated by coiling only (2.7%), and the differences were statistically significant (p = 0.043). After multivariate logistic regression analysis, treatment modality was the independent risk factor for periprocedural ischemic stroke. Compared with the coiling-only procedure, flow diverter therapy was associated with a significantly higher rate of periprocedural ischemic stroke (OR 9.931; 95% CI 1.174–84.038; p = 0.035).

Conclusions

Aneurysm size and treatment modality were associated with periprocedural ischemic stroke. Larger aneurysms were associated with increased risk of periprocedural ischemic stroke. Flow diverter therapy was associated with significantly more periprocedural ischemic stroke than the coiling procedure alone.

The role of viscoelastic testing in assessing peri-interventional platelet function and coagulation

We carried out a literature search in MEDLINE (PubMed) and EMBASE literature databases to provide a concise review of the role of viscoelastic testing in assessing peri-interventional platelet function and coagulation. The search identified 130 articles that were relevant for the review, covering the basic science of VHA and VHA in clinical settings including cardiac surgery, cardiology, neurology, trauma, non-cardiac surgery, obstetrics, liver disease, and COVID-19. Evidence from these articles is used to describe the important role of VHAs and platelet function testing in various peri-interventional setups. VHAs can help us to comprehensively assess the contribution of platelets and coagulation dynamics to clotting at the site-of-care much faster than standard laboratory measures. In addition to standard coagulation tests, VHAs are beneficial in reducing allogeneic transfusion requirements and bleeding, in predicting ischemic events, and improving outcomes in several peri-interventional care settings. Further focused studies are needed to confirm their utility in the peri-interventional case.

Contemporary Treatment of Intracranial Blood Blister Aneurysms - A Systematic Review

INTRODUCTION

Blood blister aneurysms (BBAs) are rare aneurysms affecting non-branched points of intracerebral arteries. Due to their small size and fragility, BBAs are prone to rupture, and can be challenging to diagnose and treat. Several treatment options have been suggested yet there is no consensus regarding the best modality to reduce morbidity and mortality.

MATERIALS AND METHODS

A systematic review of the literature was conducted searching for articles discussing the treatment of BBAs. Inclusion criteria included: articles published between January 2010 and August 2020, English language, with each paper including at least 15 patients. Studies included required detailed reporting of patient demographics, treatment, and patient outcomes (including complications, recurrence, neurologic functional status, and mortality).

RESULTS AND DISCUSSION

A total of 25 studies with 883 patients were included. Most were female (n = 594, 67.3%) and aneurysms were overwhelmingly located in the supraclinoid internal carotid artery (99%). Aneurysms were variable in size and mostly presented with subarachnoid haemorrhage. Endovascular treatment (n = 518, 58.7%) was more common than microsurgery (n = 365, 41.1%) while only 2 patients were managed conservatively. Complications were more common in patients treated microsurgically. Microsurgical procedures had an unfavorable outcome (mRS 4-6, GOS 1-3) rate of 27.8% (n = 100/360) while that of endovascular procedures was 14.7% (n = 70/477). Endovascular procedures had a lower mortality rate than microsurgical interventions (8.4% vs 11%).

CONCLUSION

This review demonstrates that endovascular treatment of blood blister aneurysm has reduced morbidity and mortality when compared with microsurgical treatment. Small sample sizes and substantial study heterogeneity makes strong conclusions difficult.

P2Y12 inhibitors in neuroendovascular surgery: An opportunity for precision medicine

INTRODUCTION

Dual antiplatelet therapy (DAPT), primarily the combination of aspirin with a P2Y12 inhibitor, in patients undergoing intravascular stent or flow diverter placement remains the primary strategy to reduce device-related thromboembolic complications. However, selection, timing, and dosing of DAPT is critical and can be challenging given the existing significant inter- and intraindividual response variations to P2Y12 inhibitors.

METHODS

Assessment of indexed, peer-reviewed literature from 2000 to 2020 in interventional cardiology and neuroendovascular therapeutics with critical, peer-reviewed appraisal and extraction of evidence and strategies to utilize DAPT in cardio- and neurovascular patients with endoluminal devices.

RESULTS

Both geno- and phenotyping for DAPT are rapidly and conveniently available as point-of-care testing at a favorable cost-benefit ratio. Furthermore, systematic inclusion of a quantifying clinical risk score combined with an operator-linked, technical risk assessment for potential adverse events allows a more precise and individualized approach to new P2Y12 inhibitor therapy.

CONCLUSIONS

The latest evidence, primarily obtained from cardiovascular intervention trials, supports that combining patient pharmacogenetics with drug response monitoring, as part of an individually tailored, precision medicine approach, is both predictive and cost-effective in achieving and maintaining individual target platelet inhibition levels. Indirect evidence supports that this gain in optimizing drug responses translates to reducing main adverse events and overall treatment costs in patients undergoing DAPT after intracranial stent or flow diverting treatment.

Standard vs. Modified Antiplatelet Therapy Based on Thromboelastography With Platelet Mapping for Preventing Bleeding Events in Patients Undergoing Stent-Assisted Coil for a Ruptured Intracranial Aneurysm

Background and Purpose: Stent-assisted coiling (SAC) of intracranial aneurysms is usually treated with antiplatelet therapy to reduce the risk of postoperative ischemic events. However, using the same antiplatelet therapy for all patients may increase the risk of bleeding in patients with aneurysmal subarachnoid hemorrhage (aSAH). Thromboelastography-platelet mapping (TEG-PM) measures platelet function, which reflects the effect of antiplatelet drugs. This study aimed to evaluate the benefits of individualized antiplatelet regimens based on TEG-PM parameters for patients with aSAH who underwent SAC. Methods: We retrospectively included patients with aSAH who treated with SAC during the period from June 2012 to December 2019. Patients were divided into two groups: patients whose antiplatelet therapy adjusted by TEG-PM parameters after surgery (adjustment group) and patients who were treated with standard dual antiplatelet therapy without TEG-PM test (control group). The occurrence of major/minor bleeding events, major/minor thromboembolic events, and favorable outcome (modified Rankin scale <3) were compared in both groups during hospitalization. Results: Of 188 aSAH patients considered for this study, 145 met the criteria for inclusion and were included in the analysis (93 patients in the adjustment group and 52 patients in the control group). The risks of minor bleeding events (1.1 vs. 9.6%, p = 0.02) were significantly lower in patients in the adjustment group. However, there was no significant difference in the rate of major bleeding events at discharge between adjustment and control groups (p = 0.35). The rates of thromboembolic events and favorable outcome were similar in both groups (22.6 vs. 28.8%, p = 0.42, 95.7 vs. 96.2%, p = 1.00). Furthermore, the minor thromboembolic events rate was significantly lower in the patients treated with treatment plan C (p = 0.02 for treatment plan C vs. treatment A, p = 0.03 for treatment plan C vs. treatment plan B). However, there was no significant difference in the rate of other mentioned above complications and favorable outcomes among patients treated with different antiplatelet regimens. Conclusions: Individualized antiplatelet therapy based on TEG-PM parameters might positively impact the bleeding risk of aSAH patients, without increasing the risk for clinically relevant thromboembolic events.

Differences in thromboembolism after stent-assisted coiling for unruptured aneurysms between aspirin plus clopidogrel and ticagrelor

PURPOSE

To reduce procedural thromboembolisms, tailored antiplatelet drug preparation has been used according to antiplatelet resistance for endovascular coiling of unruptured aneurysms. We compared an aspirin plus clopidogrel group with a ticagrelor group using diffusion-weighted imaging (DWI) after stent-assisted coiling for unruptured aneurysms.

METHODS

From October 2018 to April 2019, 72 patients with 78 aneurysms underwent stent-assisted coiling, with aspirin plus clopidogrel (n = 20 patients with 22 aneurysms) or ticagrelor (n = 52 patients with 56 aneurysms) as an antiplatelet preparation, and were enrolled in our study. All patients were evaluated using DWI 2 h after coiling to detect procedural thromboembolisms.

RESULTS

Postprocedure infarction was observed on DWI in 37 procedures (47.4%), and symptomatic infarction occurred in 1 procedure (1.28%). Postprocedure infarction was significantly lower in the aspirin plus clopidogrel than in ticagrelor group (27.3% vs. 55.4%, p = 0.043). Postprocedure infarction was associated with aneurysm type (sidewall aneurysm (30.8%) vs. aneurysm with incorporated branches (64.1%), p = 0.006) and guiding catheter type (single (23.8%) vs. double (56.1%), p = 0.020). Multivariable logistic regression analysis demonstrated that postprocedure infarction was related to aneurysm type (adjusted odds ratio (OR); 3.317, confidence interval (CI); 1.223-8.991, p = 0.018), guiding catheter type (adjusted OR; 2.783, CI; 0.828-9.353, p = 0.098), and antiplatelet medication (adjusted OR; 1.295, CI; 0.969-1.730, p = 0.080).

CONCLUSIONS

Postprocedure infarction was observed on DWI after stent-assisted coiling for unruptured aneurysms more frequently in the ticagrelor group than in the aspirin plus clopidogrel group. However, our study suggests that postprocedure infarction is more associated with aneurysm type than antiplatelet medication.

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.

Safety and efficacy of a pre-treatment antiplatelet regimen of unruptured intracranial aneurysms: a single-center experience

PURPOSE

Endovascular treatment of unruptured intracranial aneurysms with stent-assisted coiling or flow diverter stents requires a prophylactic antiplatelet premedication to avoid thrombo-embolic complications. Guidelines for optimal antiplatelet regimens are poorly defined. The aim of this study is to report our experience using a high dosage antiplatelet premedication regimen for patients with unruptured intracranial aneurysms undergoing endovascular treatment by stent-assisted coiling or flow diverter stents.

METHODS

From a retrospective analysis of a prospectively maintained database, we collected clinical and angiographic data of 400 procedures in 362 patients treated by stent-assisted coiling or flow diverter stents for 419 unruptured intracranial aneurysms. Descriptive and analytic statistics were performed to report morbidity, mortality, and complication rates and to demonstrate associations between variables and outcomes. Logistic multivariable regression was performed to rule out confounding factors between subgroups.

RESULTS

Thrombo-embolic complications occurred in 23/400 procedures (5.75%) and hemorrhagic complications in 19/400 procedures (4.75%). The majority of complications were minor and transient with overall procedure-related morbidity and mortality rates of 1.75% (n = 7/400) and 1.25% (n = 5/400) respectively. The co-existence of multiple cardiovascular risk factors among smoking, hypertension, dyslipidemia, and age > 65 years old was significantly associated with permanent procedure-related morbidity (p = 0.006) and thrombo-embolic complications occurrence (p = 0.034). Age alone was associated with higher permanent morbidity (p = 0.029) and was the only variable associated with higher hemorrhagic complication (p = 0.024).

CONCLUSION

In this study, the use of a high dosage antiplatelet premedication was safe and effective for the treatment of unruptured intracranial aneurysms with stent-assisted coiling or flow diverter stents. Mortality and morbidity rates compare favorably with the current literature. The thrombo-embolic complications rate is low and most of them were clinically silent. However, the hemorrhagic complications rate was substantial and a significant proportion of them were associated with mortality.

Endovascular Treatment of Ruptured Tiny Intracranial Aneurysms with Low-Profile Visualized Intraluminal Support Device

BACKGROUND

Ruptured tiny intracranial aneurysms (TIAs) have been challenging both for endovascular and neurosurgical interventions. Thus, we aimed to evaluate the safety and efficacy of low-profile visualized intraluminal support (LVIS) device in the treatment of ruptured TIAs (rTIAs).

MATERIAL AND METHODS

Among 761 intracranial aneurysms which were treated either surgically or endovascularly, 32 rTIAs underwent stent-assisted coiling with LVIS device between 2014 and 2017. Patient data were reviewed retrospectively. Clinical and radiological outcomes were recorded at discharge and mid-term follow-up.

RESULTS

Mean patient ages were 53 ± 14.5 years. Mean aneurysm size was 2.28 ± .53 mm (range, 1-2.9 mm) with a mean dome:neck ratio of 1.08 (range, .75-2.14). The LVIS stents were successfully implanted in all patients. Mean follow-up period was 9.3 ± 1.9 months (range, 6-15 months). Immediate angiographic evaluation demonstrated complete occlusion in 13 (40.6%) patients, while neck remnant and residual sac were observed in 12 (37.5%) and 7 (21.9%), respectively. All patients had moderate disability (mRS 2-3) at discharge. Number of aneurysms with complete occlusion significantly increased and 82.1% of the patients (23 of 28) demonstrated complete occlusion at follow-up (P = .0015). Among these, 27 had good outcome (mRS 0-1; 96.9%) with significant improvement compared to discharge (P = .0001). There was no recurrence or enlargement of the residual aneurysms. Additionally, there were no procedure-related complications except the one (3.6%) showing asymptomatic stenosis of the posterior cerebral artery in follow-up imagings.

CONCLUSIONS

Stent-assisted coiling of rTIAs with LVIS device provides high rates of technical success and complete occlusion at mid-term follow-up with an excellent safety profile.

Ticagrelor and Acetylsalicylic Acid after Placement of Pipeline Embolization Device for Cerebral Aneurysm: A Case Series

BACKGROUND

Dual antiplatelet therapy with acetylsalicylic acid (ASA) and a P2Y12-receptor antagonist is often used to prevent thrombotic complications after placement of a Pipeline embolization device (PED) for cerebral aneurysm. Although clopidogrel is common in this setting, high rates of nonresponse to this drug have made ticagrelor a potentially attractive alternative.

OBJECTIVE

To describe safety and efficacy outcomes for ticagrelor following PED placement, including measurement of platelet function.

METHODS

A retrospective analysis of data was completed for patients who underwent PED placement for cerebral aneurysm at a single centre between November 2015 and March 2017, with subsequent prescription of ticagrelor and ASA as dual antiplatelet therapy. The primary end point was any ischemic stroke or death within 1 year after the procedure. Intracranial hemorrhage was a secondary end point. Additionally, measurement of and values for platelet reactivity units (PRUs) during receipt of ticagrelor and ASA were evaluated.

RESULTS

A total of 29 patients were included in this retrospective study. One patient experienced ischemic stroke 226 days after placement of the PED. In addition, 3 patients died during the 1-year follow-up period for causes unrelated to stroke or bleeding complications. No cases of intracranial hemorrhage were observed. Samples for measurement of P2Y12 levels were drawn at the discretion of the neurointerventionalists, and the PRU value was measured at least once for 28 (97%) of the 29 patients. The mean number of PRU measurements per patient after initiation of ticagrelor was 2.1 (standard deviation [SD] 1). Mean PRU value after initiation of ticagrelor was 65 (SD 57).

CONCLUSIONS

In this case series describing the use of ticagrelor and ASA as dual antiplatelet therapy after PED placement for cerebral aneurysm, there was just one ischemic stroke, which occurred after the dual antiplatelet therapy had been discontinued. Further prospective trials are needed to describe the utility of ticagrelor use after PED placement, as well as its dosing and monitoring.

Preliminary Study of Tirofiban Infusion in Coil Embolization of Ruptured Intracranial Aneurysms

BACKGROUND

There have been some reports on the use of intra-arterial tirofiban in ruptured intracranial aneurysms, but few studies have reported on the use of 24 h of intravenous tirofiban infusion in patients with subarachnoid hemorrhage.

OBJECTIVE

To present our experience with intravenous tirofiban infusion, in the form of a monotherapy as well as in addition to intra-arterial tirofiban, as a prophylactic, and as a rescue management for thrombus in patients who have undergone embolization with coils for ruptured intracranial aneurysms.

METHODS

Between December 2008 and January 2015, we retrospectively reviewed 249 ruptured intracranial aneurysms that were treated with coiling at our institutions. A total of 28 patients harboring 28 ruptured and 3 unruptured intracranial aneurysms underwent intravenous tirofiban infusion during or after coil embolization of an aneurysm. Intra-arterial infusion of tirofiban via a microcatheter was also performed in 26 patients.

RESULTS

Thromboembolic formation during the procedure was detected in 25 cases. Intra-arterial tirofiban dissolved the thromboembolus under angiographic control after 10 or more minutes in 19 (76%) of 25 patients. Two intracranial hemorrhagic complications (increase in the extent of hematoma) occurred during the follow-up period. Two cases of other complications occurred: hematuria and perioral bleeding.

CONCLUSION

Intravenous tirofiban, as a monotherapy or in addition to intra-arterial tirofiban for thrombotic complications, seems to be useful as a treatment for acute aneurysm. However, alternatives to tirofiban should be considered if an associated hematoma is discovered before a patient receives a tirofiban infusion.

Abciximab (ReoPro) Dosing Strategy for the Management of Acute Intraprocedural Thromboembolic Complications during Pipeline Flow Diversion Treatment of Intracranial Aneurysms

Background

Flow diversion with the Pipeline embolization device (PED) is an effective neuro-endovascular method and increasingly accepted for the treatment of cerebral aneurysms. Acute in situ thrombosis is a known complication of PED procedures. There is limited experience in the flow diversion literature on the use of abciximab (ReoPro) for the management of acute thrombus formation in PED cases.

Methods

Data were collected retrospectively on patients who received intra-arterial (IA) ReoPro with or without subsequent intravenous (IV) infusion during PED flow diversion treatment of intracranial aneurysms.

Results

A total of 30 cases in patients with a mean age of 56.7 years (range 36-84) and a mean aneurysm size of 8.6 mm (range 2-25) were identified to have intraprocedural thromboembolic complications during PED treatment. IA ReoPro was administered in all cases, with 20 cases receiving increments of 5-mg boluses and 10 cases receiving a 0.125 mg/kg IA bolus (half cardiac dosing). Complete or partial recanalization was achieved in 100% of the cases. IV ReoPro infusion at 0.125 μg/kg/min for 12 h was administered postprocedurally in 22 cases with a residual thrombus. Postprocedurally, 18 patients were transitioned from clopidogrel (Plavix) to prasugrel (Effient). The majority of the cases (23/30; 77%) were discharged home. Periprocedural intracranial hemorrhage was noted in 2 cases (7%) and radiographic infarct was noted in 4 cases (13%), with an overall mortality of 0% at the time of initial discharge. Clinical follow-up was available for 28/30 patients. The average duration of follow-up was 11.7 months, at which time 23/28 (82%) of the patients had a modified Rankin Scale score of 0.

Conclusions

IA ReoPro administration is an effective and safe rescue strategy for the management of acute intraprocedural thromboembolic complications during PED treatment. Using a dosing strategy of either 5-mg increments or a 0.125 mg/kg IA bolus (half cardiac dosing) can provide high rates of recanalization with low rates of hemorrhagic complications and long-term morbidity.

Procedural complexity independent of P2Y12 reaction unit (PRU) values is associated with acute in situ thrombosis in Pipeline flow diversion of cerebral aneurysms

Background

Acute in situ thrombosis is an ischaemic phenomenon during Pipeline embolisation device (PED) procedures with potentially high morbidity and mortality. There is controversy regarding the role of platelet function testing with P2Y12 assay as a predictor of intraprocedural thromboembolic events. There is limited knowledge on whether procedural complexity influences these events.

Methods

Data were collected retrospectively on 742 consecutive PED cases at a single institution. Patients with intraprocedural acute thrombosis were compared with patients without these events.

Results

A cohort of 37 PED cases with acute in situ thrombosis (mean age 53.8 years, mean aneurysm size 8.4 mm) was matched with a cohort of 705 PED cases without intraprocedural thromboembolic events (mean age 56.4 years, mean aneurysm size 6.9 mm). All patients with in situ thrombosis received intra-arterial and/or intravenous abciximab. The two groups were evenly matched in patient demographics, previous treatment/subarachnoid hemorrhage (SAH) and aneurysm location. There was no statistical difference in postprocedural P2Y12 reaction unit (PRU) values between the two groups, with a mean of 156 in the in situ thrombosis group vs 148 in the control group (p=0.5894). Presence of cervical carotid tortuosity, high cavernous internal carotid artery grade, need for multiple PED and vasospasm were not significantly different between the two groups. The in situ thrombosis group had statistically significant longer fluoroscopy time (60.4 vs 38.4 min, p<0.0001), higher radiation exposure (3476 vs 2160 mGy, p<0.0001), higher rates of adjunctive coiling (24.3% vs 8.37%, p=0.0010) and higher utilisation of balloon angioplasty (37.8% vs 12.2%, p<0.0001). Clinically, the in situ thrombosis cohort had higher incidence of major and minor stroke, intracerebral haemorrhage and length of stay.

Conclusions

Predictors of procedural complexity (higher radiation exposure, longer fluoroscopy time, adjunctive coiling and need for balloon angioplasty) are associated with acute thrombotic events during PED placement, independent of PRU values.

Phosphorylcholine surface modified flow diverter associated with reduced intimal hyperplasia

Background

Optical coherence tomography (OCT) is a high-resolution, intra-vascular diagnostic technique widely used for the characterization of vascular pathologies and optimization of stent implantation during percutaneous coronary intervention. OCT was used to investigate the in vivo vascular response to a new phosphorylcholine surface modified flow diverter (sPED).

Methods

In an in vivo rabbit aneurysmal model, we used two different types of flow diverters (classic Pipeline – cPED; and sPED) with or without dual antiplatelet therapy (four groups, n=10 per group). OCT cross-sectional area measurements were compared with histology in all animals. Neointimal hyperplasia (NIH) ratio was compared between OCT and histology at five different levels for each stent. The severity of NIH was also compared between the different stents, antiplatelet protocols, and vessel locations.

Results

OCT was used to calculate in-stent hyperplasia in 227 different locations corresponding to histology sections. OCT measurement strongly correlated with gold standard histology (r2=0.83; slope=0.988; P<0.0001). sPED had significantly less in-stent NIH than non-treated flow diverters (mean percent of lumen reduction 5.7% for sPED versus 8.9% for cPED; P<0.0001). The NIH ratio was slightly higher with dual antiplatelet therapy (DAPT) (NIH ratio=7.9% with DAPT versus 6.8% without DAPT; P<0.05). Complete and near complete occlusion rates of the aneurysms were not different with the cPED or sPED.

Conclusion

OCT is a promising technique for immediate and long-term evaluation of flow diverter stent treatments. In an animal model, phosphorylcholine surface modified flow diverters induces less NIH after stent implant without reducing aneurysm occlusion rates.

Relationship between adverse events and antiplatelet drug resistance in neurovascular intervention: a meta-analysis

Background

This meta-analysis aimed to evaluate the association between antiplatelet resistance and the risk of procedure-related complications in neurovascular interventions.

Methods

We identified relevant articles by searching electronic databases and reviewed the reference lists of selected papers. The risk of adverse events between antiplatelet responders and hyporesponders during neurointervention was compared in eligible clinical studies. Risk ratios (RRs) and 95% CIs were pooled using a random-effects meta-analysis.

Results

Of 2134 potentially relevant studies, our search identified 15 studies enrolling a total of 2365 patients. Pooled RRs showed thromboembolic events (TEE) were more frequent in hyporesponders (RR 2.634, 95% CI 1.465 to 4.734). However, hemorrhagic complications did not differ between the two groups (RR 1.236, 95% CI 0.642 to 2.380). In subgroup analysis, hyporesponders showed a higher prevalence of TEE with standard antiplatelet medication, but there was no obvious difference in TEE between the two arms when using a modified antiplatelet medication (RR 3.645, 95% CI 1.537 to 8.646; and RR 1.877, 95% CI 0.749 to 4.751). Studies using stent placement for aneurysms showed a higher TEE rate in hyporesponders (RR 3.221, 95% CI 1.899 to 5.464).

Conclusion

Antiplatelet resistance was significantly associated with TEE in neurointervention, and this adverse event was associated with individually-intensified antiplatelet medication as well as the type of neurointerventional procedure. Our findings support the use of antiplatelet resistance assays and tailored antiplatelet medications in neurovascular stent placement as a management strategy to reduce thromboembolic risk.

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

BACKGROUND

The use of antiplatelet medications to prevent thrombosis in the treatment of cerebral aneurysms with stents has become widely emphasized.

OBJECTIVE

To compare low-dose prasugrel with clopidogrel in stent-assisted coil embolization of intracranial aneurysms.

METHODS

This is a retrospective review of 311 aneurysms from 297 patients who underwent stent-assisted endovascular coil embolization of unruptured intracranial aneurysm between November 2014 and March 2017. Thromboembolic and hemorrhagic adverse events were compared between 207 patients who received low-dose prasugrel (PSG group) and 90 patients who received clopidogrel (CPG group).

RESULTS

P2Y12 reaction unit (PRU) values were significantly lower in the PSG group (PSG group vs CPG group, 132.3 ± 76.9 vs 238.1 ± 69.1; P &lt; .001); the percentage of inhibition was also statistically higher in the PSG group (54.0 ± 26.0% vs 20.8 ± 18.6%; P &lt; .001). Thromboembolic events occurred less frequently in the PSG group than in the CPG group (0.9% vs 6.4%; P = .01), whereas there was no significant difference in the percentage of hemorrhagic complications (0.5% vs 2.2%; P = .22). In the multivariate analysis, clopidogrel as the antiplatelet medication was the sole significant risk factor for thromboembolism in this series of patients undergoing stent-assisted coil embolization.

CONCLUSION

Use of low-dose PSG as an antiplatelet premedication is quick, effective, and safe for stent-assisted coil embolization of unruptured intracranial aneurysms. Prasugrel premedication significantly lowered the frequency of thromboembolic events without increasing the risk of hemorrhage.

Influence of CYP2C19 genetic polymorphisms on clinical outcomes of intracranial aneurysms treated with stent-assisted coiling

OBJECTIVE

To investigate the influence of CYP2C19 genetic polymorphisms on clinical outcomes of intracranial aneurysms treated with stent-assisted coiling.

METHODS

Between September 2014 and October 2015, we prospectively recruited 215 patients with intracranial aneurysms who were treated with stent-assisted coiling. CYP2C19 genotypes were determined and clopidogrel response was tested. The primary endpoints included symptomatic or silent ischemic events, and bleeding events. The secondary endpoint was clinical outcome at 3 months.

RESULTS

Of the 215 patients, 108 (50.2%) were classified as intermediate metabolizers (IMs, CYP2C19*1/*2, *1/*3), 76 (35.3%) as extensive metabolizers (EMs, CYP2C19*1/*1) and 31 (14.4%) as poor metabolizers (PMs, CYP2C19*2/*2, *2/*3, *3/*3). Carriers of CYP2C19 loss-of-function (LOF) alleles (*2 or *3, p=0.001), especially PMs (p=0.004), had an increased risk for clopidogrel resistance. After the procedures, cerebral ischemic events occurred in 69 patients (32.1%) and bleeding was seen in 20 patients (9.3%). In comparison with IMs and PMs, EMs had a lower risk for ischemic events (21.1% vs 37.0% and 41.9%, p=0.02 and 0.027, respectively) and a relatively higher risk for bleeding events (18.4% vs 5.6% and 0%, p=0.006 and 0.01, respectively). Based on multivariate analysis, the carriage of CYP2C19 LOF alleles (p=0.032) and clopidogrel resistance (p=0.047) were considered as predictors of cerebral ischemic events, and EMs were significantly associated with bleeding (p=0.002). Posterior circulation aneurysms (p=0.038), hemorrhagic history (p=0.001) and poor metabolic genotypes (p=0.001) could result in poor clinical outcomes (modified Rankin Scale >2).

CONCLUSIONS

CYP2C19 genetic polymorphisms had significant influence on the antiplatelet effect of clopidogrel, and could be considered as risk factors of ischemic or bleeding events and even clinical outcomes of patients with intracranial aneurysms treated with stent-assisted coiling.

Ischemic Stroke After Treatment of Intraprocedural Thrombosis During Stent-Assisted Coiling and Flow Diversion

BACKGROUND AND PURPOSE

Intraprocedural thrombosis poses a formidable challenge during neuroendovascular procedures because the risks of aggressive thromboembolic treatment must be balanced against the risk of postprocedural hemorrhage. The aim of this study was to identify predictors of ischemic stroke after intraprocedural thrombosis after stent-assisted coiling and pipeline embolization device placement.

METHODS

A retrospective analysis of intracranial aneurysms treated with stent-assisted coiling or pipeline embolization device placement between 2007 and 2016 at 4 major academic institutions was performed to identify procedures that were complicated by intraprocedural thrombosis.

RESULTS

Intraprocedural thrombosis occurred in 34 (4.6%) procedures. Postprocedural ischemic stroke and hemorrhage occurred in 20.6% (7/34) and 11.8% (4/34) of procedures complicated by intraprocedural thrombosis, respectively. Current smoking was an independent predictor of ischemic stroke. There was no statistically significant difference in the rate of ischemic stroke or postprocedural hemorrhage with the use of abciximab compared with the use of eptifibatide in treatment of intraprocedural thrombosis.

CONCLUSIONS

Current protocols for treatment of intraprocedural thrombosis associated with placement of intra-arterial devices were effective in preventing ischemic stroke in ≈80% of cases. Current smoking was the only independent predictor of ischemic stroke.

Prophylactic Antiplatelet Medication in Endovascular Treatment of Intracranial Aneurysms: Low-Dose Prasugrel versus Clopidogrel

BACKGROUND AND PURPOSE

Prophylactic antiplatelet medication is beneficial in decreasing thromboembolic complications during endovascular treatment of unruptured intracranial aneurysms. The efficacy may be limited by variability of individual response to antiplatelet medication, especially clopidogrel. We compared the efficacy of 2 antiplatelet medications, low-dose prasugrel and clopidogrel, in patients undergoing endovascular treatment of unruptured aneurysms.

MATERIALS AND METHODS

From November 2014 to July 2015, 194 patients with a total of 222 unruptured aneurysms underwent endovascular treatment at a single institution. Laboratory and clinical data from the prospectively maintained registry were used in this study. Antiplatelet medication was given the day before endovascular treatment (prasugrel 20 mg or 30 mg or clopidogrel 300 mg). Response to the antiplatelet medication was measured by the VerifyNow system. Periprocedural adverse event rates between the 2 groups were compared.

RESULTS

There were no significant differences in the baseline characteristics of patients and aneurysms between the 2 groups. The P2Y12 reaction unit values were lower (clopidogrel group versus prasugrel group, 242.7 ± 69.8 vs 125.7 ± 79.4; P < .0001) and percentage inhibition values were higher (22.1% ± 19.7% vs 60.2 ± 24.7%; P < .0001) in the prasugrel group. There were no thromboembolic events, but there was 1 procedural bleed in each group, without any clinical consequences.

CONCLUSIONS

The prasugrel group showed more effective and consistent platelet inhibition. We may omit the antiplatelet response assay with the low-dose prasugrel premedication before the endovascular treatment of patients with unruptured aneurysms. Further study is required to determine whether there is benefit of this strategy regarding clinical outcome.

LVIS Stent Versus Enterprise Stent for the Treatment of Unruptured Intracranial Aneurysms

OBJECTIVE

This retrospective study compared clinical and angiographic outcomes between LVIS and Enterprise stents.

MATERIALS AND METHODS

From November 2014 to December 2015, total 190 patients with 208 unruptured intracranial aneurysms were coiled assisted by LVIS and Enterprise stents. Procedure-related complications, clinical outcomes, and angiographic results were analyzed retrospectively.

RESULTS

A total of 92 patients with 96 aneurysms received LVIS stents and 98 patients with 112 aneurysms were treated with Enterprise stents. Procedure-related complications occurred in 10.9% of patients (2 hemorrhagic events and 8 thromboembolic events) in the LVIS stents group whereas 16.3% (1 hemorrhage, 1 mass effect, and 14 thromboembolic events) in the Enterprise stents group. No statistical significant differences in thromboembolic (P = 0.263), hemorrhagic complications (P = 0.611), and favorable clinical outcomes (modified Rankin Scores of 0-2) (P = 0.379) were found between 2 groups. A greater initial complete or near-complete obliteration was found in the LVIS stents group compared with the Enterprise stents group (96.9% vs. 88.4%, P = 0.034). Larger aneurysm size (P = 0.048) was an independent predictor of procedure-related complications in univariate analysis.

CONCLUSIONS

Compared with Enterprise stents, LVIS stents may achieve greater complete or near-complete occlusion rate. There was no significant difference in procedural-related complications and clinical outcomes between LVIS and Enterprise stents.