Clot composition and recanalization outcomes in mechanical thrombectomy

BACKGROUND

Mechanical thrombectomy (MT) has become standard for large vessel occlusions, but rates of complete recanalization are suboptimal. Previous reports correlated radiographic signs with clot composition and a better response to specific techniques. Therefore, understanding clot composition may allow improved outcomes.

METHODS

Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin-eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of first-pass effect (FPE, modified Thrombolysis in Cerebral Infarction 2c/3) and the number of passes.

RESULTS

A total of 1430 patients of mean±SD age 68.4±13.5 years (median (IQR) baseline National Institutes of Health Stroke Scale score 17.2 (10.5-23), IV-tPA use 36%, stent-retrievers (SR) 27%, contact aspiration (CA) 27%, combined SR+CA 43%) were included. The median (IQR) number of passes was 1 (1-2). FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for red blood cell (RBC)-rich (P<0.0001), platelet-rich (P=0.003), and mixed (P<0.0001) clots. Fibrin-rich and platelet-rich clots required a higher number of passes than RBC-rich and mixed clots (median 2 and 1.5 vs 1, respectively; P=0.02). CA showed a trend towards a higher number of passes with fibrin-rich clots (2 vs 1; P=0.12). By gross appearance, mixed/heterogeneous clots had lower FPE rates than red and white clots.

CONCLUSIONS

Despite the lack of correlation between clot histology and FPE, our study adds to the growing evidence supporting the notion that clot composition influences recanalization treatment strategy outcomes.

Abstract 99: Clot Composition And Reperfusion Outcomes In 1430 Mechanical Thrombectomy Patients: Analysis Of The Stroke Thromboembolism Registry Of Imaging And Pathology

Background: Understanding clot composition may allow for better technical planning and improved outcomes in mechanical thrombectomy (MT). We sought to correlate clot composition with reperfusion outcomes in MT.

Methods: Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin and eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of First-Pass Effect (mTICI2c/3, FPE) and the number of device passes.

Results: A total of 1430 patients (mean age, 68.4±13.5years; median [IQR] baseline NIHSS,17.2 [10.5-23]; IV-tPA use, 36%; Stent-Retrievers [SR], 27%; Contact Aspiration [CA], 27%; Combined SR + CA, 43%) were included. The median [IQR] number of passes was 1 [1-2]. FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for RBC-rich (P<0.0001), platelet-rich (P=0.003), and mixed (P<0.0001) clots. Fibrin-rich and platelet-rich clots required a higher number of passes compared to RBC-rich and mixed clots (median, 2 and 1.5 vs.1, respectively, P=0.02). CA displayed a trend towards a higher number of passes with fibrin-rich clots (2 vs.1, P=0.12). By gross appearance, mixed/heterogeneous clots had lower FPE rates than red and white clots.

Conclusion: Despite the lack of correlation between clot histology and FPE in the overall population, our study adds to the growing body of evidence supporting the notion that clot composition influences reperfusion treatment strategy outcomes. Additional studies are needed.

Quantification of clot spatial heterogeneity and its impact on thrombectomy

BACKGROUND

Compositional and structural features of retrieved clots by thrombectomy can provide insight into improving the endovascular treatment of ischemic stroke. Currently, histological analysis is limited to quantification of compositions and qualitative description of the clot structure. We hypothesized that heterogeneous clots would be prone to poorer recanalization rates and performed a quantitative analysis to test this hypothesis.

METHODS

We collected and did histology on clots retrieved by mechanical thrombectomy from 157 stroke cases (107 achieved first-pass effect (FPE) and 50 did not). Using an in-house algorithm, the scanned images were divided into grids (with sizes of 0.2, 0.3, 0.4, 0.5, and 0.6 mm) and the extent of non-uniformity of RBC distribution was computed using the proposed spatial heterogeneity index (SHI). Finally, we validated the clinical significance of clot heterogeneity using the Mann-Whitney test and an artificial neural network (ANN) model.

RESULTS

For cases with FPE, SHI values were smaller (0.033 vs 0.039 for grid size of 0.4 mm, P=0.028) compared with those without. In comparison, the clot composition was not statistically different between those two groups. From the ANN model, clot heterogeneity was the most important factor, followed by fibrin content, thrombectomy techniques, red blood cell content, clot area, platelet content, etiology, and admission of intravenous tissue plasminogen activator (IV-tPA). No statistical difference of clot heterogeneity was found for different etiologies, thrombectomy techniques, and IV-tPA administration.

CONCLUSIONS

Clot heterogeneity can affect the clot response to thrombectomy devices and is associated with lower FPE. SHI can be a useful metric to quantify clot heterogeneity.

Correlation of von Willebrand factor and platelets with acute ischemic stroke etiology and revascularization outcome: an immunohistochemical study

BACKGROUND

Platelets and von Willebrand factor (vWF) are key components of acute ischemic stroke (AIS) emboli. We aimed to investigate the CD42b (platelets)/vWF expression, its association with stroke etiology and the impact these components may have on the clinical/procedural parameters.

METHODS

CD42b/vWF immunostaining was performed on 288 emboli collected as part of the multicenter STRIP Registry. CD42b/VWF expression and distribution were evaluated. Student's t-test and χ² test were performed as appropriate.

RESULTS

The mean CD42b and VWF content in clots was 44.3% and 21.9%, respectively. There was a positive correlation between platelets and vWF (r=0.64, p<0.001**). We found a significantly higher vWF level in the other determined etiology (p=0.016*) and cryptogenic (p=0.049*) groups compared with cardioembolic etiology. No significant difference in CD42b content was found across the etiology subtypes. CD42b/vWF patterns were significantly associated with stroke etiology (p=0.006*). The peripheral pattern was predominant in atherosclerotic clots (36.4%) while the clustering (patchy) pattern was significantly associated with cardioembolic and cryptogenic origin (66.7% and 49.8%, respectively). The clots corresponding to other determined etiology showed mainly a diffuse pattern (28.1%). Two types of platelets were distinguished within the CD42b-positive clusters in all emboli: vWF-positive platelets were observed at the center, surrounded by vWF-negative platelets. Thrombolysis correlated with a high platelet content (p=0.03*). vWF-poor and peripheral CD42b/vWF pattern correlated with first pass effect (p=0.03* and p=0.04*, respectively).

CONCLUSIONS

The vWF level and CD42b/vWF distribution pattern in emboli were correlated with AIS etiology and revascularization outcome. Platelet content was associated with response to thrombolysis.

Histological composition of retrieved emboli in acute ischemic stroke is independent of pre-thrombectomy alteplase use

BACKGROUND AND PURPOSE

Given recent evidence suggesting the clot composition may be associated with revascularization outcomes and stroke etiology, clot composition research has been a topic of growing interest. It is currently unclear what effect, if any, pre-thrombectomy thrombolysis has on clot composition. Understanding this association is important as it is a potential confounding variable in clot composition research. We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients who did and did not receive pre-treatment tPA to study the effect of tPA on clot composition.

MATERIALS AND METHODS

Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using Martius Scarlett Blue (MSB) staining and area of the clot was also measured on the gross photos. Student's t test was used for continuous variables and chi-squared test for categorical variables.

RESULTS

A total of 1430 patients were included in this study. Mean age was 68.4±13.5 years. Overall rate of TICI 2c/3 was 67%. A total of 517 patients received tPA (36%) and 913 patients did not (64%). Mean RBC density for the tPA group was 42.97±22.62% compared to 42.80±23.18% for the non-tPA group (P=0.89). Mean WBC density for the tPA group was 3.74±2.60% compared to 3.42±2.21% for the non-tPA group (P=0.012). Mean fibrin density for the tPA group was 26.52±15.81% compared to 26.53±15.34% for the non-tPA group (P=0.98). Mean platelet density for the tPA group was 26.22±18.60% compared to 26.55±19.47% for the non-tPA group (P=0.75). tPA group also had significantly smaller clot area compared to non-tPA group.

CONCLUSIONS

Our study 1430 retrieved emboli and ischemic stroke patients shows no interaction between tPA administration and clot composition. These findings suggest that tPA does not result in any histological changes in clot composition.

Pipeline embolization of proximal middle cerebral artery aneurysms: A multicenter cohort study

BACKGROUND AND PURPOSE

Flow diversion of aneurysms located in the M1 segment and middle cerebral artery bifurcation with Pipeline embolization device is sometimes performed, but further study is needed to support its regular use in aneurysm treatment. Here, we report measures of safety and efficacy for Pipeline embolization in the proximal middle cerebral artery in a multi-center cohort.

MATERIALS AND METHODS

Clinical and angiographic data of eligible patients were retrospectively obtained from participating centers and assessed for key clinical and angiographic outcomes. Additional details were extracted for patients with complications.

RESULTS

In our multi-center cohort, complete aneurysm occlusion was achieved in 71% (17/24) of treated aneurysms. There were no deaths or disabling strokes, but non-disabling ischemic strokes occurred in 8% (2/24) of patients. For aneurysms in the M1 segment, complete aneurysm occlusion was observed in 75% (12/16) of aneurysms, aneurysm volume reduction was observed in 100% (16/16) of aneurysms, and non-disabling ischemic strokes occurred in 13% (2/16) of patients. For aneurysms at the middle cerebral artery bifurcation, complete aneurysm occlusion was observed in 63% (5/8) of aneurysms, aneurysm volume reduction occurred in 88% (7/8) of aneurysms, and ischemic or hemorrhagic complications occurred in 0% (0/8) of patients.

CONCLUSION

Pipeline embolization of cerebral aneurysms in the M1 segment and middle cerebral artery bifurcation demonstrated a 71% rate of complete aneurysm occlusion. There were no deaths or disabling strokes, but there was an 8% rate of non-disabling ischemic strokes.

Pipeline embolization of distal posterior inferior cerebellar artery aneurysms

BACKGROUND AND PURPOSE

Flow diversion is commonly used to treat intracranial aneurysms in various regions of the cerebral vasculature, but is only approved for use in the internal carotid arteries. Treatment of distal PICA aneurysms with PED is sometimes performed but has not been well studied. Here, we report our experience with flow diversion of distal PICA aneurysms with PED.

MATERIALS AND METHODS

Clinical and angiographic data of eligible patients was retrospectively obtained and assessed for key demographic characteristics and clinical and angiographic outcomes. Principal outcomes included rates of aneurysm occlusion, ischemic or hemorrhagic complication, technical complication, and in-stent stenosis.

RESULTS

Three female and 2 male patients underwent placement of PED in the PICA for treatment of 5 distal PICA aneurysms. Clinical and angiographic follow-up was obtained for all patients. Complete aneurysm occlusion was observed in 100% (5/5) of treated aneurysms at 6 month and longest angiographic follow-up. While there were no ischemic or device-related complications, delayed hemorrhagic complications occurred in 20% (1/5) of patients.

CONCLUSION

Pipeline embolization of distal PICA aneurysms can be performed in select patients. Further study is necessary in larger cohorts to better define clinical scenarios in which flow diversion in the distal PICA should be considered.

Safety and efficacy results of the Flow Redirection Endoluminal Device (FRED) stent system in the treatment of intracranial aneurysms: US pivotal trial

OBJECTIVE

To evaluate the safety and effectiveness of the Flow Redirection Endoluminal Device (FRED) flow diverter in support of an application for Food and Drug Administration approval in the USA.

METHODS

145 patients were enrolled in a prospective, single-arm multicenter trial. Patients with aneurysms of unfavorable morphology for traditional endovascular therapies (large, wide-necked, fusiform, etc) were included. The trial was designed to demonstrate non-inferiority in both safety and effectiveness, comparing trial results with performance goals (PGs) established from peer-reviewed published literature. The primary safety endpoint was death or major stroke (National Institutes of Health Stroke Scale score ≥4 points) within 30 days of the procedure, or any major ipsilateral stroke or neurological death within the first year. The primary effectiveness endpoint was complete occlusion of the target aneurysm with ≤50% stenosis of the parent artery at 12 months after treatment, and in which an alternative treatment of the target intracranial aneurysm had not been performed.

RESULTS

145 patients underwent attempted placement of a FRED device, and one or more devices were placed in all 145 patients. 135/145 (93%) had a single device placed. Core laboratory adjudication deemed 106 (73.1%) of the aneurysms large or giant. A safety endpoint was experienced by 9/145 (6.2%) patients, successfully achieving the safety PG of <15%. The effectiveness PG of >46% aneurysm occlusion was also achieved, with the effectiveness endpoint being met in 80/139 (57.6%) CONCLUSION: As compared with historically derived performance benchmarks, the FRED flow diverter is both safe and effective for the treatment of appropriately selected intracranial aneurysms.

CLINICAL REGISTRATION NUMBER

NCT01801007.

Histological evaluation of acute ischemic stroke thrombi may indicate the occurrence of vessel wall injury during mechanical thrombectomy

Background

Several animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.

Objective

To investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.

Methods

As part of the multicenter STRIP registry, 277 clots from 237 patients were analyzed using Martius Scarlett Blue stain and immunohistochemistry for CD34 (endothelial cells) and smooth muscle actin (smooth muscle cells).

Results

MT devices used were aspiration catheters (100 cases), stentriever (101 cases), and both (36 cases). VWI was found in 33/277 clots (12%). There was no significant correlation between VWI and MT device. The degree of damage varied from grade I (mild intimal damage, 24 clots), to grade II (relevant intimal and subintimal damage, 3 clots), and III (severe injury, 6 clots). VWI clots contained significantly more erythrocytes (p=0.006*) and less platelets/other (p=0.005*) than non-VWI clots suggesting soft thrombus material.

Thrombolysis correlated with a lower rate of VWI (p=0.04*). VWI cases showed a significantly higher number of passes (2 [1–4] vs 1 [1–3], p=0.028*) and poorer recanalization outcome (p=0.01*) than cases without VWI.

Conclusions

Histological markers of VWI were present in 12% of AIS thrombi, suggesting that VWI might be related to MT. VWI was associated with soft thrombus consistency, higher number of passes and poorer revascularization outcome. There was no significant correlation between VWI and MT device.

Per pass analysis of thrombus composition retrieved by mechanical thrombectomy

BACKGROUND AND AIM

Mechanical thrombectomy (MT) for large vessel occlusion often requires multiple passes to retrieve the entire thrombus load. In this multi-institutional study we sought to examine the composition of thrombus fragments retrieved with each pass during MT.

METHODS

Patients who required multiple passes during thrombectomy were included. Histopathological evaluation of thrombus fragments retrieved from each pass was performed using Martius Scarlet Blue staining and the composition of each thrombus component including RBC, fibrin and platelet was determined using image analysis software.

RESULTS

154 patients underwent MT and 868 passes was performed which resulted in 263 thrombus fragments retrieval. The analysis of thrombus components per pass showed higher RBC, lower fibrin and platelet composition in the pass 1 and 2 when compared to pass 3 and passes 4 or more combined (P values <0.05). There were no significant differences between thrombus fragments retrieved in pass 1 and pass 2 in terms of RBC, WBC, fibrin, and platelet composition (P values >0.05). Similarly, when each composition of thrombus fragments retrieved in pass 3 and passes 4 or more combined were compared with each other, no significant difference was noted (P values >0.05).

CONCLUSION

Our findings confirm that thrombus fragments retrieved with each pass differed significantly in histological content. Fragments in the first passes were associated with lower fibrin and platelet composition compared to fragments retrieved in passes three and four or higher. Also, thrombus fragments retrieved after failed pass were associated with higher fibrin and platelet components.

Association between clot composition and stroke origin in mechanical thrombectomy patients: analysis of the Stroke Thromboembolism Registry of Imaging and Pathology

BACKGROUND

We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients to study the association between histological composition and stroke etiology METHODS: Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using martius scarlet blue (MSB) staining, and quantification for red blood cells (RBCs), white blood cells (WBCs), fibrin and platelets was performed using Orbit Image Software. A Wilcoxon test was used for continuous variables and χ² test for categorical variables.

RESULTS

1350 patients were included in this study. The overall rate of Thrombolysis In Cerebral Infarction (TICI) 2c/3 was 68%. 501 patients received tissue plasminogen activator (tPA) (37%). 267 patients (20%) had a large artery atherosclerosis (LAA) source, 662 (49%) a cardioembolic (CE) source, 301 (22%) were cryptogenic, and the remainder had other identifiable sources including hypercoagulable state or dissection. LAA thrombi had a higher mean RBC density (46±23% vs 42±22%, p=0.01) and a lower platelet density (24±18% vs 27±18%, p=0.03) than CE thrombi. Clots from dissection patients had the highest mean RBC density (50±24%) while clots from patients with a hypercoagulable state had the lowest mean RBC density (26±21%).

CONCLUSIONS

Our study found statistically significant but clinically insignificant differences between clots of CE and LAA etiologies. Future studies should emphasize molecular, proteomic and immunohistochemical characteristics to determine links between clot composition and etiology.

Social media usage for neurointerventionalists: report of the Society of NeuroInterventional Surgery Standards and Guidelines Committee

The purpose of this publication is to provide a review of social media usage by neurointerventionalists. Using published literature and available local, regional, and national guidelines or laws, we reviewed data on social media usage as it pertains to neurointerventional surgery. Recommendations are provided based on the quality of information and conformity of medico-legal precedent and law. Social media is a growing entity as it is used both promotionally and educationally. Neurointerventionalists may post de-identified radiographic images with discussions, but should be conscientious and adhere to applicable laws and regulations, strict ethical codes, and institutional policies.

Woven EndoBridge device for ruptured aneurysms: perioperative results of a US multicenter experience

BACKGROUND

The Woven EndoBridge (WEB) device is approved in the USA for treatment of unruptured wide-neck bifurcation aneurysms. However, the safety and effectiveness of the WEB device in the treatment of ruptured intracranial aneurysms is not clear. We aim to evaluate the perioperative safety and effectiveness of the WEB device in patients with ruptured intracranial aneurysms.

METHODS

This retrospective study, conducted at eight centers in the USA, included patients with ruptured intracranial aneurysms treated with the WEB device in the setting of subarachnoid hemorrhage (SAH). Safety outcomes included intraoperative complications such as vessel perforation, thromboembolic events, and postoperative hemorrhagic or thromboembolic complications based on radiologic imaging. The primary effectiveness outcome was adequate (complete and neck remnant) aneurysm occlusion, according to the Raymond-Roy classification.

RESULTS

A total of 91 patients with 94 ruptured intracranial aneurysms were included (mean age 57.7±15.2 years; 68.1% women; 82.9% wide-necked). Aneurysms were located in the anterior communicating artery (42/94, 44.6%), middle cerebral artery (16/94, 17%), and basilar artery (15/94, 16%). Adequate occlusion was achieved in 48.8% (41/84) and 80.0% (40/50) at discharge and last follow-up (mean of 3.4 months), respectively. At discharge, procedural-related morbidity was 3.3% (3/91) and there was no procedure-related mortality. No re-rupture or delayed aneurysm rupture was observed.

CONCLUSIONS

This study demonstrates the perioperative safety and effectiveness of the WEB device for the treatment of patients with ruptured intracranial aneurysms in the setting of SAH, with low periprocedural morbidity and mortality. Long-term follow-up is warranted.

Dual antiplatelet therapy does not improve outcomes after aneurysmal subarachnoid hemorrhage compared with aspirin monotherapy

BACKGROUND

The pathophysiology of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH) may include platelet activation and microthrombi formation. Antiplatelet therapy may reduce the incidence of DCI and improve clinical outcomes after aSAH. This study compared outcomes among aSAH patients receiving aspirin monotherapy versus dual antiplatelet therapy (DAPT).

METHODS

Aneurysmal subarachnoid hemorrhage patients treated at a single institution between November 2011 and December 2017 were divided according to whether they received aspirin monotherapy or DAPT after endovascular treatment. Baseline characteristics and outcomes of the groups were compared, including incidences of delayed cerebral ischemia, bleeding complications, symptomatic vasospasm, in-hospital mortality, and functional status 6 months after discharge.

RESULTS

During the study period, 142 patients met study inclusion criteria, of which 123 were treated with aspirin monotherapy (87 %) and 19 were treated with DAPT (13 %). There was no statistically significant difference between the aspirin monotherapy and DAPT groups with respect to incidences of delayed cerebral ischemia (4.9 vs 10.5 %; p = 0.32), symptomatic vasospasm (13.0 vs 15.8 %; p = 0.74), or good clinical outcome at 6-month follow up (73.3 vs 66.7 %; p = 0.56). The DAPT group experienced a higher incidence of in-hospital mortality (21 vs 5.7 %; p = 0.02), but DAPT did not remain independently predictive of this outcome on regression analysis. There was a trend toward a higher bleeding complication rate in the DAPT group (0.8 vs 5.3 %; p = 0.13).

CONCLUSIONS

DAPT does not reduce the incidence of DCI or improve outcomes in aSAH patients, and may increase the risk of clinically significant bleeding complications.

Endovascular Treatment of Posterior Cerebral Artery Aneurysms With Flow Diversion: Case Series and Systematic Review

BACKGROUND

Flow diversion of posterior cerebral artery (PCA) aneurysms has not been widely reported, possibly owing to concerns regarding parent vessel size and branch vessel coverage.

OBJECTIVE

To examine the safety and effectiveness of PCA aneurysm flow diverter treatment.

METHODS

Retrospective review of PCA aneurysms treated with the Pipeline Embolization Device (PED; Medtronic Inc, Dublin, Ireland) at 3 neurovascular centers, including periprocedural complications and clinical and angiographic outcomes. Systematic review of the literature identified published reports of PCA aneurysms treated with flow diversion. Rates of aneurysm occlusion and complications were calculated, and outcomes of saccular and fusiform aneurysm treatments were compared.

RESULTS

Ten PCA aneurysms in 9 patients were treated with the PED. There were 2 intraprocedural thromboembolic events (20%), including 1 symptomatic infarction and 1 delayed PED thrombosis. Eight of 10 patients returned to or improved from their baseline functional status. Complete aneurysm occlusion with parent vessel preservation was achieved in 75% (6/8) of cases at mean follow-up of 16.7 mo. Eleven of 12 (92%) major branch vessels covered by a PED remained patent. Including the present study, systematic review of 15 studies found a complete aneurysm occlusion rate of 88% (30/34) and complication rate of 26% (10/38), including 5 symptomatic ischemic strokes (13%; 5/38). Fusiform aneurysms more frequently completely occluded compared with saccular aneurysms (100% vs 70%; P = .03) but were associated with a higher complication rate (43% vs 9%; P = .06).

CONCLUSION

The safety and effectiveness profile of flow diverter treatment of PCA aneurysms may be acceptable in select cases.

Platelet-Rich Emboli in Cerebral Large Vessel Occlusion Are Associated With a Large Artery Atherosclerosis Source

Background and Purpose- Nearly 30% of large vessel occlusion acute ischemic stroke clots are from an unknown source. We assessed histological clot composition in a series of patients with large vessel occlusion and investigated correlations between clot composition and stroke pathogenesis. Methods- As part of the multi-institutional STRIP registry (Stroke Thromboembolism Registry of Imaging and Pathology), consecutive emboli retrieved during mechanical thrombectomy were stained using Martius Scarlett Blue and analyzed using machine learning software. We assessed proportions of red blood cells, fibrin, platelets, and white blood cells. Correlations between clot components and stroke pathogenesis (large artery atherosclerosis, cardioembolism, and stroke of undetermined pathogenesis) were assessed using SPSS22. Results- One hundred five patients were included. The proportion of platelet-rich clots (55.0% versus 21.2%; P=0.005) and percentage of platelet content (22.1±4.2% versus 13.9±14.2%; P=0.03) was significantly higher in the large artery atherosclerosis group compared with the cardioembolic group. The proportion of platelet-rich clots (50.0% versus 21.2%; P=0.024) was also significantly higher in the cryptogenic group compared with cardioembolic cases. Large artery atherosclerosis and cryptogenic cases had a similar proportion of platelet-rich clots (55.0% versus 50.0%; P=0.636). There was no significant difference between stroke pathogenesis and the other major clot components. Conclusions- High platelet content of emboli is associated with a large artery atherosclerosis etiology of large vessel occlusion.

Current endovascular strategies for posterior circulation large vessel occlusion stroke: report of the Society of NeuroInterventional Surgery Standards and Guidelines Committee

Background

The aim of this publication is to provide a detailed update on the diagnosis, treatment, and endovascular techniques for posterior circulation emergent large vessel occlusion (pc-ELVO).

Methods

We performed a review of the literature to specifically evaluate this disease and its treatments.

Results

Data were analyzed, and recommendations were reported based on the strength of the published evidence and expert consensus.

Conclusion

While many questions about pc-ELVO remain to be studied, there is evidence to support particular practices in its evaluation and treatment.

Platelet-rich clots as identified by Martius Scarlet Blue staining are isodense on NCCT

BACKGROUND

Current studies on clot characterization in acute ischemic stroke focus on fibrin and red blood cell composition. Few studies have examined platelet composition in acute ischemic stroke clots. We characterize clot composition using the Martius Scarlet Blue stain and assess associations between platelet density and CT density.

MATERIALS AND METHOD

Histopathological analysis of the clots collected as part of the multi-institutional STRIP registry was performed using Martius Scarlet Blue stain and the composition of the clots was quantified using Orbit Image Analysis (www.orbit.bio) machine learning software. Prior to endovascular treatment, each patient underwent non-contrast CT (NCCT) and the CT density of each clot was measured. Correlations between clot components and clinical information were assessed using the χ² test.

RESULTS

Eighty-five patients were included in the study. The mean platelet density of the clots was 15.7% (2.5-72.5%). There was a significant correlation between platelet-rich clots and the absence of hyperdensity on NCCT, (ρ=0.321, p=0.003*, n=85). Similarly, there was a significant inverse correlation between the percentage of platelets and the mean Hounsfield Units on NCCT (ρ=-0.243, p=0.025*, n=85).

CONCLUSION

Martius Scarlet Blue stain can identify patients who have platelet-rich clots. Platelet-rich clots are isodense on NCCT.

Pipeline Embolization of Vertebrobasilar Aneurysms—A Multicenter Case Series

BACKGROUND

The Pipeline Embolization Device (PED) has been increasingly used for the treatment of posterior circulation aneurysms. The purpose of the present study was to examine the clinical and angiographic outcomes of patients with vertebrobasilar aneurysms treated with the PED.

METHODS

We performed a retrospective review of vertebrobasilar aneurysms treated with the PED at 4 high-volume neurovascular centers. Patient, aneurysm, and procedural data were collected, including perioperative and delayed complications. Aneurysm occlusion on follow-up imaging studies was defined as complete (100%), near-complete (>90%), or incomplete (<90%) occlusion.

RESULTS

The cohort included 35 patients with 37 vertebrobasilar aneurysms who underwent 36 treatment sessions. Of the 35 patients, 10 were men (29%), and the mean patient age was 54.1 years (range, 32-75). Eight patients (23%) underwent urgent treatment because of a ruptured aneurysm (n = 6), brainstem perforator stroke (n = 1), or post-traumatic pseudoaneurysm (n = 1). Of the 37 aneurysms, 22 arose from the vertebral artery (59%) and 15 from the basilar artery (41%). Also, 19 were saccular aneurysms (51%), with a mean size of 7.7 mm (range, 1.7-38.0); 17 were fusiform aneurysms (46%), with a mean size of 11.0 mm (range, 4.3-34); and 1 was a 2.9-mm blister aneurysm. The overall procedural complication rate was 14% (5 of 36), including 3 neurologically symptomatic complications. At a mean follow-up period of 14 months (range, 3-59), 24 of 34 aneurysms (71%) were completely occluded and 29 of 34 (85%) were completely or near-completely occluded.

CONCLUSION

Our results show that Pipeline embolization of vertebrobasilar aneurysms is associated with acceptable occlusion and complication rates.

Balloon-assisted coiling of cerebral aneurysms with the dual-lumen Scepter XC balloon catheter: Experience at two high-volume centers

BACKGROUND

The Scepter XC is a dual-lumen balloon catheter that accommodates a 0.014-inch microwire and can be used for balloon-assisted coiling of cerebral aneurysms. We describe our experience with the use of this device.

METHODS

Two high-volume institution neurointerventional databases were retrospectively reviewed for cerebral aneurysms treated with balloon-assisted coiling using the Scepter XC balloon catheter. Patient demographics, aneurysm characteristics, and procedural details were recorded. Major procedure-related neurologic complications were defined as events that caused an increase in modified Rankin Scale that persisted for more than 1 week after the procedure. Follow-up aneurysm occlusion was assessed using the Raymond-Roy classification.

RESULTS

During the study period, 231 aneurysms were treated in 219 patients (152 women, 67 men) with a mean age of 58.4 ± 12.2 years. Mean aneurysm size was 6.1 ± 3.1 mm, with a mean neck diameter of 3.1 ± 1.3 mm. In total, 77.5% of aneurysms were wide necked, and 39.8% were treated in the setting of subarachnoid hemorrhage. The major complication rate was 0.9% (2/231) per treated aneurysm, including one stroke and one death related to intraoperative aneurysm rupture. Excluding patients who died, angiographic follow up was available for 85.3% (191/224) of aneurysms. During a mean follow up of 17.4 ± 13.0 months (range, 1.7-66.5 months), Raymond-Roy 1 and 2 occlusion rates were 56.5% (108/191) and 35.6% (68/191), respectively. The retreatment rate was 12.6% (24/191).

CONCLUSION

Our experience using the coaxial dual-lumen Scepter XC for balloon-assisted coiling demonstrates acceptable aneurysm occlusion and complication rates.

Larger ACE 68 aspiration catheter increases first-pass efficacy of ADAPT technique

PURPOSE

To report the efficacy of A Direct Aspiration first-Pass Thrombectomy (ADAPT) technique with larger-bore ACE aspiration catheters as first-line treatment for anterior circulation emergent large vessel occlusions (ELVOs), and assess for the presence of a first-pass effect with ADAPT.

METHODS

We retrospectively reviewed 152 consecutive patients with anterior circulation ELVOs treated with the ADAPT technique as first-line treatment using ACE60, 64, or 68 at our institution. Baseline characteristics, procedural variables, and modified Rankin Scale (mRS) at 90 days were recorded.

RESULTS

Fifty-seven patients were treated with ACE60 (37.5%), 35 with ACE64 (23%), and 60 with ACE68 (39.5%). Median groin puncture to reperfusion time was 30 min with ACE60, 26 min with ACE64, and 19.5 min with ACE68. Successful reperfusion after the first ADAPT pass was 33% with ACE60 and 53% with ACE68 (P=0.04). The stent-retriever rescue rate was 26% with ACE60, 3% with ACE64, and 10% with ACE68 (P=0.004). In multivariate logistic regression analysis, use of the ACE68 aspiration catheter was an independent predictor of successful reperfusion after the first ADAPT pass (P=0.016, OR1.67, 95% CI 1.1 to 2.54), and successful reperfusion after the first ADAPT pass was an independent predictor of good clinical outcome at 90 days (P=0.0004, OR6.2, 95% CI 2.27 to 16.8).

CONCLUSION

Use of the larger-bore ACE 68 aspiration catheter was associated with shorter groin puncture to reperfusion time, higher rate of successful reperfusion after the first ADAPT pass, and lower rate of stent-retriever rescue. Further, a first-pass effect was demonstrated in our ADAPT patient cohort.

Clinical and angiographic outcomes in patients with intracranial aneurysms treated with the pipeline embolization device: intra-procedural technical difficulties, major morbidity, and neurological mortality decrease significantly with increased operator experience in device deployment and patient management

PURPOSE

Flow diversion constitutes a pivotal advancement in endovascular intracranial aneurysm treatment, but requires development of a new skill set. The aim of this study is to determine whether outcomes after treatment with the Pipeline Embolization Device improve with experience.

METHODS

We retrospectively reviewed all patients with intracranial aneurysms treated with Pipeline at two centers over a 4.5-year period. Baseline patient and aneurysm characteristics, complications, and angiographic outcomes were analyzed.

RESULTS

One hundred forty patients underwent 150 Pipeline procedures to treat 167 intracranial aneurysms during the study period, 109 women, mean age 55.4 years. One hundred twenty-six aneurysms were ICA, mean size 10.2 mm and mean neck 6.4 mm. Intra-procedural technical difficulties were higher during the first 75 procedures compared with the subsequent 75 (13.3 vs 2.7%; p = 0.03), as combined major morbidity and neurological mortality (14.7 vs 4%; p = 0.046). In multivariate regression analysis, increased operator experience with Pipeline remained an independent predictor of intra-procedural technical difficulties (p = 0.02, odds ratio (OR) 0.015, 95% CI 0.0004-0.55) and combined major morbidity and neurological mortality (p = 0.03, OR 0.16, 95% CI 0.03-0.84). At last follow-up, 123 aneurysms were completely occluded (81.5%, mean 24 months). In our cohort, age ≤ 53 years was an independent predictor of complete aneurysm occlusion at last follow-up (p = 0.001, OR 0.92, 95% CI 0.88-0.97). Five aneurysms were retreated (3.3%).

CONCLUSION

The Pipeline embolization device is an effective treatment for intracranial aneurysms. The risk of intra-procedural technical difficulties and combined major morbidity and neurological mortality decreases significantly with increased operator experience in Pipeline deployment and patient management.

Pipeline embolization of posterior communicating artery aneurysms associated with a fetal origin posterior cerebral artery

BACKGROUND AND PURPOSE

Flow diversion may have advantages in the treatment of posterior communicating artery (PComA) aneurysms associated with a fetal origin posterior cerebral artery (PCA), which can be challenging to treat with conventional techniques. However, a PComA incorporated into the aneurysm may prevent or delay aneurysm occlusion. Also, coverage of a fetal origin PCA risks infarction of a large vascular territory. The purpose of this study was to examine the safety and effectiveness of using the Pipeline Embolization Device (PED) to treat PComA aneurysms associated with a fetal origin PCA.

PATIENTS AND METHODS

Retrospective review of PComA aneurysms associated with a fetal origin PCA treated with the PED at two neurovascular centers was performed. Periprocedural complications and clinical and angiographic outcomes were reviewed.

RESULTS

Seven female patients underwent a total of seven PED procedures to treat seven PcomA aneurysms associated with a fetal origin PCA. The symptomatic complication rate was 14% (1/7) per patient and 13% (1/8) per procedure. Angiographic follow up was obtained for 6 of 7 aneurysms. Follow-up DSA at 5-7 months after treatment demonstrated complete occlusion of 17% (1/6) of aneurysms. One aneurysm was retreated with a second PED and occlusion was demonstrated 36 months after the second treatment, yielding an overall complete occlusion rate of 33% (2/6).

CONCLUSIONS

PED treatment was largely ineffective at treating PComA aneurysms associated with a fetal origin PCA, and should only be considered when conventional treatment options, including microsurgical clipping, are not feasible.

A case of right middle cerebral artery 'tendonectomy' following mitral valve replacement surgery

Following mechanical mitral valve replacement surgery, a 69-year-old woman had an ischemic stroke in the right middle cerebral artery territory. Mechanical thrombectomy showed the embolus to be a piece of chordae tendineae excised during the valve replacement surgery.

A case of right middle cerebral artery 'tendonectomy' following mitral valve replacement surgery

Following mechanical mitral valve replacement surgery, a 69-year-old woman had an ischemic stroke in the right middle cerebral artery territory. Mechanical thrombectomy showed the embolus to be a piece of chordae tendineae excised during the valve replacement surgery.

Efficacy of a two-test protocol for achieving a therapeutic response to clopidogrel prior to elective endovascular intracranial aneurysm treatment and an 'induced' postoperative hyper-response

INTRODUCTION

Variable response to clopidogrel can impact perioperative risk in elective endovascular intracranial aneurysm treatment. The present study aims to determine the efficacy of a two-test protocol in reaching in-range preoperative P2Y12 reaction units (PRU) of 60-240 and the rate of postoperative conversion to hyper-response.

METHODS

A 17-day two-test protocol (with tests on days 10 and 17) for patients starting clopidogrel in anticipation of elective endovascular intracranial aneurysm treatment was introduced in February 2013 at our institution. Records for patients started on this protocol through December 2014 were reviewed for preoperative and postoperative PRUs, patient and procedural data, and thromboembolic and hemorrhagic events within 30 days. Logistic regression analyses were performed to identify predictors of postoperative hyper-response (p<0.05 considered significant).

RESULTS

103 patients (80 women) of mean age 57 years were included. 74 patients (71.8%) were in range at the first test and 92 patients (89.3%) were in range at the second test. A postoperative test was performed in 82 patients (79.6%) at a median of 9 days. 51 patients (62.2%) converted into hyper-responders. There were five non-disabling strokes and one intracranial hemorrhage within 30 days. There were no major strokes (modified Rankin Scale score >2) or deaths. There was no association between out-of-range PRU and thromboembolic or hemorrhagic neurological complications.

CONCLUSIONS

The protocol achieves in-range preoperative PRU by the second test in almost nine of 10 patients. Nearly two-thirds of patients exhibited postoperative hyper-response to clopidogrel. Out-of-range PRU was not associated with thromboembolic or hemorrhagic neurological complications in this cohort of patients with actively managed P2Y12 inhibition.

Comparison of clinical outcomes in patients with acute ischemic strokes treated with mechanical thrombectomy using either Solumbra or ADAPT techniques

PURPOSE

To compare rates of symptomatic intracranial hemorrhage (SICH) and good clinical outcome at 90 days in patients with ischemic strokes from anterior circulation emergent large vessel occlusions (ELVO) treated with mechanical thrombectomy using either Solumbra or A Direct Aspiration first-Pass Thrombectomy (ADAPT) techniques.

METHODS

We compared clinical characteristics, procedural variables, and clinical outcomes in patients with anterior circulation ELVOs treated with mechanical thrombectomy using either a Solumbra or ADAPT technique at our institution over a 38-month period. SICH was defined using the SITS-MOST criteria. A good clinical outcome was defined as a modified Rankin Scale score of 0-2 at 90 days.

RESULTS

One hundred patients were included, 55 in the Solumbra group and 45 in the ADAPT group. Patients in the ADAPT group had higher National Institutes of Health Stroke Scale (NIHSS) (19.2 vs 16.8, p=0.02) and a higher proportion of internal carotid artery terminus thrombi (42.2% vs 20%, p=0.03) than patients in the Solumbra group. Patients in the ADAPT group had a trend toward a lower rate of SICH than patients in the Solumbra group (2.2% vs 12.7%, p=0.07). Patients in the ADAPT group had a significantly higher rate of good clinical outcome at 90 days than patients in the Solumbra group (55.6% vs 30.9%, p=0.015). Use of the ADAPT technique (OR 6 (95% CI 1.0 to 31.2), p=0.049) was an independent predictor of a good clinical outcome at 90 days in our cohort.

CONCLUSIONS

In our cohort, the ADAPT technique was associated with significantly higher good clinical outcomes at 90 days in patients with acute ischemic stroke due to anterior circulation ELVOs treated with mechanical thrombectomy.

Incidence of delayed ipsilateral intraparenchymal hemorrhage after stent-assisted coiling of intracranial aneurysms in a high-volume single center

INTRODUCTION

Delayed ipsilateral intraparenchymal hemorrhage (IPH) has been reported following technically successful treatment of intracranial aneurysms using flow-diverting stents in up to 8.5% of patients. We report a similar, though less frequent phenomenon in the setting of stent-assisted coil embolization.

METHODS

Institutional review board approval was obtained. A retrospective analysis of a prospective neurointerventional procedure registry was performed to review all IPHs that occurred in aneurysm patients within 90 days of endovascular treatment performed between November 2002 and November 2014 at one institution. Age, sex, hypertension, dual antiplatelet therapy, and technical details of the procedure were recorded.

RESULTS

A total of 1697 patients underwent endovascular treatment of an intracranial aneurysm without a flow diverter at our institution during the study period. Among these, 138 patients underwent stent-assisted coiling (8.1%). Of these, three patients (2.2%) suffered a delayed IPH within the vascular territory distal to the treated lesion (one woman, median age 60 years).

CONCLUSIONS

Recently described in the setting of flow diversion, delayed ipsilateral IPH is not limited to flow-diverting stents. Though less frequent, a potential for this complication may exist following any intracranial stenting procedure, possibly related to hemorrhagic conversion of microembolic phenomena in the setting of dual antiplatelet or anticoagulation therapy.