Mechanical Recanalization Research Articles

Apparent Diffusion Coefficient Signal Intensity Ratio Predicts the Effect of Revascularization on Ischemic Cerebral Edema

Background: Apparent diffusion coefficient (ADC) imaging is a biomarker of cytotoxic injury that predicts edema formation and outcome after ischemic stroke. It therefore has the potential to serve as a “tissue clock” to describe the extent of ischemic injury and potentially predict response to therapy. The goal of this study was to determine the relationship between baseline ADC signal intensity, revascularization, and edema formation. Methods: We examined the ADC signal intensity ratio (ADCr) of the stroke lesion (defined as the baseline DWI hyperintense region) compared to the contralateral normal hemisphere in 65 subjects from the Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy trial. The associations between ADCr, neurologic outcome, and cerebral edema were examined. Finally, we explored the interaction between baseline ADCr and vessel recanalization at day 7 on post-stroke edema. Results: We found that lower initial ADCr was associated with a worse outcome on the modified Rankin Scale (mRS) at 90 days (52.2% of those with ADCr <64% were mRS 5–6 vs. 19.1% with ADCr ≥64%, p = 0.006). Those subjects with reconstitution of flow distal to the initial vessel occlusion showed greater normalization of ADCr on follow-up scan (increase in ADCr of 16.4 ± 2.07 vs. 1.99 ± 4.33%, p = 0.0039). In those patients with low baseline ADCr, successful revascularization was associated with reduced edema (median swelling volume 164 mL [interquartile range (IQR) 53.3–190 mL] vs. 20.7 mL [IQR 3.20–55.1 mL], p = 0.024). Conclusions: This study reaffirms the association of ADCr with outcome after stroke, supports the idea that reperfusion may attenuate rather than enhance post-stroke edema, and indicates that the degree of edema with and without revascularization may be predicted by ADCr.

Prehospital stroke scales and large vessel occlusion: A systematic review.

Time sensitivity for pharmacological and mechanical arterial recanalization in acute ischemic stroke influences the choice of the reference hospital. The accurate selection and identification of patients with high probability of a large vessel occlusion (LVO) in the prehospital setting improve the rationalization of the transport in the more suitable centers. Aim of this analysis was to determine the diagnostic accuracy of prehospital stroke scales detecting LVO. Studies were searched into MEDLINE, EMBASE, and CINHAL databases between January 1990 and September 2017. Principal measurements of the meta-analysis were the overall accuracy level, sensitivity, and specificity of prehospital stroke scales. Nineteen scoring systems were included in the analysis coming from 13 studies. A total of 9824 patients were considered. Although a higher heterogeneity was observed in the analysis, three scores showed better results in predicting a LVO (the stroke Vision, Aphasia, Neglect assessment, the National Institute of Health Stroke scale and the Los Angeles Motor Scale). We observed significant differences of overall accuracy only for scores including hemineglect as cortical neurological sign (P<.05). This meta-analysis suggests that some prehospital scoring systems including cortical signs showed better accuracy to predict stroke due to LVO. However, the assessment of these signs could be difficult to investigate by paramedics and personnel of Emergency Medical Services, and for this reason, further prospective evaluations are needed.

Abstract TP268: Distribution of Acute Ischemic Strokes After Implementation of Endovascular Guidelines in Louisiana

Objective: To highlight the distribution of acute ischemic strokes (AIS) after implementation of endovascular guidelines. Background: Louisiana Emergency Response Network (LERN) is an organization with a mission to build comprehensive statewide systems of care for time-sensitive conditions including stroke. Four levels of stroke centers were recognized in 2013. Level 1: Comprehensive stroke center; Level 2: Primary stroke center; Level 3: Acute stroke ready hospital and Level 4: Non-stroke hospitals. As of 2017, there are 2 comprehensive stroke centers in Louisiana and 15 primary stroke centers. Statewide education was provided regarding mechanical endovascular recanalization (MER) for large vessel occlusion (LVO) in AIS as AHA/ASA guidelines were updated in 2015. Design/Methods: Louisiana hospital inpatient discharge database for year 2014 and 2015 was retrospectively analyzed. Distribution of AIS and MER based on hospital level were explored. Results: A total of 9396 patients with AIS were identified in dataset for year 2014 and 10409 for the year 2015. Proportion of AIS treated in Level 1, 2 and 3 hospitals increased in 2015 {Level 1: 2014 VS 2015: 1034 (11%) VS 1342 (13%); Level 2: 3946 (42%) VS 5035 (48%); level 3: 3195 (34%) VS 3610 (35%)}. Proportion of AIS patients in level 4 hospitals declined in 2015 {Level 4: 2014 VS 2015: 1221 (13%) VS 422 (4%)}. In 2014, 8.2% (770/9396) received any form of recanalization therapy compared to 9.5% in 2015 (989/10409), with higher proportions in Level 1 (22.2% VS 26.2%) and 2 centers (9.4% VS 10.2%) than Level 3 (4.1% VS 3.2%) and 4 (2.6% VS 1.4%). In 2015, 1.8% of patients with AIS had MER; this compares to 0.8% in 2014. Conclusion: The reduction of patients treated in Level 4 hospitals in 2015 suggests our pre-hospital destination protocol facilitated transport to appropriate facilities. The proportion of patients with AIS receiving any form of recanalization increased in 2015, specifically in Level 1 and 2 centers. Improved destination of acute stroke patients likely contributed to increased recanalization rate and utility of MER. Statewide implementation of a revised initial destination protocol respecting the endovascular guidelines should lead to more LVO AIS patients receiving MER.

Abstract WP21: Different View on Clinical Application of Tirofiban After Mechanical Arterial Recanalization in Acute Ischemic Stroke

Tirofiban, an antiplatelet drug and glycoprotein-IIb/IIIa inhibitor, widely used in cardiovascular events, appears to be safe and effective in cerebrovascular stroke. However, its efficacy post-endovascular therapy raised concern due to an association with increased risk of fatal intracerebral hemorrhage (ICH) and poor outcome in ischemic patients (Kellert et al. 2013). The success of 5 randomized clinical trials in stroke therapy in 2015 utilizing new generation endovascular intervention prompted this study of continuous intravenous administration of Tirofiban after thrombectomy with the Solitaire stent, one of the two new devices, in patients with acute ischemic stroke. A consecutive series of patients (n=28) who received Solitaire stent thrombectomy from January 2017 to the present was enrolled. 22 of the 28 patients were eligible for intravenous Tirofiban treatment for 24 h after receiving endovascular therapy. 6 patients were excluded because of no vessel recanalization, vessel recanalization achieved by other devices, or ICH after endovascular therapy. The incidence of symptomatic ICH and death was recorded. The number of thrombectomy attempts and device manipulation time within vessels were measured as potential markers for endothelial damage. The NIH stroke and modified Rankin scales were assessed at 7 days and 3 months, respectively. In all 22 patients who received Tirofiban after endovascular therapy, none had symptomatic ICH nor died from treatment. Successful recanalization rate (TICI≥2b) was achieved in 18 (86.4%) of 22 patients after endovascular therapy. As compared to the study by Kellert et al., the lower average device passages (1.2 vs 2.0) and short device manipulation time (56 vs 104 min) together suggested less endothelial damage. Of our patients, 77.3% showed neurological improvement at 7 days and 59.1% patients had favorable outcomes with a Modified Rankin scale of 0 to 2 at 3 months. These favorable outcomes were similar to those achieved in the 5 positive randomized trials. In conclusion, the continuous application of Tirofiban post-Solitaire stent thrombectomy appears to be safe and effective in acute ischemic stroke. Reduced endothelial damage may play a key role in clinical outcomes with Tirofiban application.

Akutna respiratorna insuficijencija uzrokovana papilomatozom laringsa

Recurrent respiratory papillomatosis is a rare disease, most commonly localized in the larynx. The prevalence is 1-4 diseased in every 100 000 people. It often starts in early childhood and is characterized by a chronic, recurrent and unpredictable development. Human papilloma virus type 6 and 11 is the cause of a disease that manifests itself with gradual development of hoarseness, vising, snoring dyspnea and a feeling of a strange body in the throat. A clinical picture of an acute respiratory insufficiency is shown, caused by recurrent respiratory papillomatosis. In March 2017. when the patient had experienced sudden choking, cyanosis, inspiratory stridor and trouble breathing. an urgent tracheotomy was conducted and tube no. 7 was reinforced in order to determine the level of obstruction from the larynx to the trachea. The patient was hospitalized in the department for intensive care, with an ensured airway and good saturation. Under anesthesia, a flexible bronchoscopy was used to remove a mucous cap from the trachea, after which a papillomatosis formation was seen at the entrance of the tracheostomy over the entire circumference of the lumen, which decreased the lumen to 15%. A consecutive mechanical recanalization was done with rigid tubes with the extraction of the papilloma with forceps. After the intervention, the trachea became transient up to 90% of the lumen. Patient is afterwards stable, soon released and has appeared for a checkup a month later, with satisfying results. This was his 55th hospitalization because of the primary disease. Repetition of tracheotomy increases the risk of spreading the infection into the trachea and lungs but is sometimes necessary due to unexpected life threatening situations in those suffering from papillomatosis in the larynx.

Letter re: Evaluation of hyperacute infarct volume using ASPECTS and brain CT perfusion core volume.

Demeestere et al.1 compared hyperacute infarct volume using the Alberta Stroke Program Early CT Score (ASPECTS) and brain CT perfusion and found no significant difference. ASPECTS and CT perfusion-based studies have already established their critical role in selecting patients for thrombolysis and mechanical recanalization.2,3 In this study, ASPECTS or CT perfusion core volume was compared with MRI diffusion-weighted imaging (DWI) lesion volume.1 However, MRI was performed within 100 minutes (median 60 minutes) of CT perfusion and 49% of patients received thrombolysis before MRI.

Mechanical recanalization in ischemic anterior circulation stroke within an 8-hour time window: a real-world experience.

We aimed to assess the safety and effectiveness of mechanical recanalization in patients with ischemic stroke in the anterior circulation within 8 h since symptoms onset and with unknown onset time. We compared time intervals <6 h vs. 6-8 h/unknown onset time, as only limited data are available for a time window beyond 6 h. Our cohort included 110 consecutive patients (44 males; mean age, 73.0±11.5 years) with ischemic stroke in the anterior circulation due to the acute occlusion of a large intracranial artery who underwent mechanical recanalization within an 8-hour time window or with unknown onset time. All patients underwent unenhanced computed tomography (CT) of the brain, CT angiography of the cervical and intracranial arteries and digital subtraction angiography. Perfusion CT was performed in patients beyond a 6-hour time window/with unknown onset time. We collected the following data: baseline characteristics, presence of risk factors, neurologic deficit at the time of treatment, time to therapy, recanalization rate, and 3-month clinical outcome. Successful recanalization was defined as Thrombolysis in Cerebral Infarction score of 2b/3 and good clinical outcome as modified Rankin scale value of 0-2 points. Successful recanalization was achieved in 82 patients (74.5%): in 61 patients treated within 6 h (73.5%), 7 patients treated within 6-8 h (63.6%), and 13 patients with unknown onset time (81.3%). Good 3-month clinical outcome was achieved in 61 patients (55.5%): in 46 patients treated within 6 h (55.4%), 5 patients treated within 6-8 h (45.5%), and 10 patients with unknown onset time (62.5%). Recanalization success or clinical outcome were not significantly different between patients treated at different time windows. Our data confirms the safety and effectiveness of mechanical recanalization performed in carefully selected patients with ischemic stroke in the anterior circulation within 8 h of stroke onset or with unknown onset time in everyday practice.

Prehospital care for stroke patients

The effectiveness of thrombolysis or mechanical recanalization for acute stroke is higher, the sooner these therapies are started. Therefore, acute stroke patients need to be evaluated by qualified staff for these therapies as soon as possible. Lay persons need to identify the typical symptoms of stroke as an emergency and act accordingly by calling the emergency medical system (EMS). The EMS team reassesses the symptoms and prompts cerebral imaging. Cerebral imaging is performed ideally in hospitals with a stroke unit where subsequent (stroke) treatments occur. On the way, the emergency team will measure and stabilize vital functions and obtain further important clinical information. Telemedicine allows communicating exact time of onset and severity of symptoms, as well as comorbidities and medication of the patient to the respective hospital. Thereby, the intrahospital workload will be disencumbered and accelerated. Some EMS vehicles now carry point-of-care laboratories and may measure lab values en route (glucose and INR [International Normalized Ratio] for example). Some ambulances are not only equipped with qualified staff, telemedicine technique, and point-of-care labs but even computer tomography (CT) to perform imaging. Such mobile stroke emergency mobiles (STEMO) or mobile stroke units may perform thrombolysis prehospitally. Prehospital thrombolysis has been proven to be initiated faster and is safe. Preliminary results even suggest superiority to intrahospital thrombolysis with respect to clinical outcome. Moreover, STEMO may perform CT-angiography and assess intracranial large-vessel status. If intracranial large-vessel occlusion is present, patients will be brought directly to hospitals able to perform mechanical recanalization. Thus, secondary transports are no longer required.

Reperfusion after ischemic stroke is associated with reduced brain edema

Rapid revascularization is highly effective for acute stroke, but animal studies suggest that reperfusion edema may attenuate its beneficial effects. We investigated the relationship between reperfusion and edema in patients from the Echoplanar Imaging Thrombolysis Evaluation Trial (EPITHET) and Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy (MR RESCUE) cohorts. Reperfusion percentage was measured as the difference in perfusion-weighted imaging lesion volume between baseline and follow-up (day 3–5 for EPITHET; day 6–8 for MR RESCUE). Midline shift (MLS) and swelling volume were quantified on follow-up MRI. We found that reperfusion was associated with less MLS (EPITHET: Spearman ρ = −0.46; P < 0.001, and MR RESCUE: Spearman ρ = −0.49; P < 0.001) and lower swelling volume (EPITHET: Spearman ρ = −0.56; P < 0.001, and MR RESCUE: Spearman ρ = −0.27; P = 0.026). Multivariable analyses performed in EPITHET and MR RESCUE demonstrated that reperfusion independently predicted both less MLS (ß coefficient = −0.056; P = 0.025, and ß coefficient = −0.38; P = 0.028, respectively) and lower swelling volumes (ß coefficient = −4.7; P = 0.007, and ß coefficient = −10.7; P = 0.009, respectively), after adjusting for age, sex, NIHSS, admission glucose and follow-up lesion size. Taken together, our data suggest that even modest improvement in perfusion is associated with less brain edema in EPITHET and MR RESCUE.

Recent Trends in Clot Retrieval Devices: A Review.

Stroke is the second leading cause of death worldwide and in Europe. Even with gold standard medical management of acute ischemic stroke, which is intravenous (IV) thrombolysis by administration of recombinant tissue plasminogen activator (rt-PA), the mortality rate remains the same. Intra-arterial (IA) thrombolysis therapy also did not achieve significant results and was not approved by the US Food and Drug Administration (FDA) because of limited sample size. This encouraged scientists and engineers to develop endovascular clot retrieval devices for the mechanical recanalization of the occluded arteries in stroke patients. Although the initial designs of clot retrieval devices failed, efforts to improve these devices continue. Recently clot retrieval devices were approved by the FDA as first-line treatment along with IV rt-PA. This article gives an in-depth review of different clot retrieval devices which includes MERCI (the first), the Penumbra Aspiration System, EmboTrap®II, stent retrievers, and the way forward with the new FDA clearance of the devices as first-line treatment for acute ischemic stroke along with IV rt-PA. The review also includes a comparison of clot retrieval devices to gold standard treatment.

Mechanical Recanalization Using Solitaire AB Device for Severe Thromboembolic Events in Endovascular Treatment of Intracranial Aneurysms.

Severe thromboembolism with complete occlusion of the proximal arteries during or after coil embolization can cause serious neurologic deficits. The study aimed to assess the effectiveness and safety of Solitaire AB device as a rescue therapy for severe thromboembolic complications in the endovascular treatment of intracranial aneurysms. Between February 2013 and April 2016, 1047 intracranial aneurysms treated with endovascular procedures were retrospectively reviewed in our center. Severe thromboembolisms occurred in ten patients and were treated by Solitaire AB device including clot retriever and permanent stent deployment. The location of arterial occlusion was distal to the aneurysm rather than the coil/parent artery interface or in-stent area. Four patients had distal thromboembolic events before coil embolization, and six patients had it after coiling. The complete arterial recanalization (TICI 3) was achieved in all patients, and no cerebral hemorrhage was related to the procedure after the rescue therapy. Among these patients with the aforementioned neurovascular procedures, the mean Glasgow Outcome Scale (GOS) score was 4.5 (ranging 3-5) and eight cases had good outcome with a score of GOS 4-5 at discharge, while eight patients presented mRS ≤2 at 3-month follow-up. These results demonstrate that mechanical recanalization using Solitaire AB device seems to be effective and safe as a rescue therapy for severe thromboembolic events during cerebral aneurysm embolization.

The potential use of transdermal drug delivery for the prophylaxis and management of stroke and coronary artery disease.

In 2013, cardiovascular disease was responsible for 30.8% (800,937) of all 2,596,993 deaths, or approximately 1 of every 3 deaths while stroke caused about 1 of every 20 deaths in the United States [1]. To put it in context, about 795,000 people continue to have a new or recurrent stroke (ischemic or hemorrhagic) [1] in the USA. Mechanical vascular recanalization and thrombolysis with tissue plasminogen activator are the only clinically useful approaches available now for the management of ischemic stroke [2]. Antiplatelet therapy with aspirin and/or clopidogrel is also a common practice utilized for the management of stroke, acute myocardial infarction and coronary artery disease [3]. There are two different but closely related approaches to improve therapy- to develop new disease-modifying agents or to find alternative drug administration routes for existing drugs. Transdermal drug delivery leverages the advantages of injections and tablets- painlessness, minimal invasiveness and the avoidance of presystemic metabolism and can potentially be applied to medications used for the prevention and/or management of coronary artery disease and stroke.

The CD31 molecule: a possible neuroprotective agent in acute ischemic stroke?

BackgroundThe transmembrane receptor molecule CD31 is known to have immunomodulatory functions, suggesting a possible neuroprotective effect in the context of acute ischemic stroke by restricting an over-activation of secondary immunological processes. This study examines the density of CD31+ cells in mechanically extracted thrombi of stroke patients with the aim to test whether the occurrence of CD31+ cells was associated with a beneficial clinical outcome in those patients.MethodsThrombi of 122 consecutive patients with large anterior circulation stroke were collected during intracranial mechanical recanalization. Out of these, 86 immunostained specimens of adequate quality could be analysed. The density of CD31+ cells was quantified and compared with clinical outcome data of the affected patients.ResultsThe density of CD31+ cells was positively related to early patient improvement (ΔNIHSS, r = 0.283, p = 0,012) with an even clearer relationship after exclusion of patients who died in the early hospital phase (r = 0.371, p = 0.001). This finding stayed stable also in the multivariate analysis after corrrection for other outcome-influencing factors (p = 0.049).ConclusionThis study shows a stable relation between CD31+ cells and early clinical improvement of patients with acute ischemic stroke. This finding is in line with recent reports showing immunomodulatory and potential neuroprotective effects of CD31, suggesting that CD31 may be a promising neuroprotective agent in stroke patients.

Mechanical recanalization for clot occlusion of venous access ports: experimental study using ports with clot occlusion.

To test the hypothesis that mechanical injection of saline is safe and effective in restoring patency of totally implantable venous access ports (TIVAPs) with clot occlusion. We devised an experimental port model for the evaluation of mechanical TIVAP recanalization prior to its clinical application. The clot TIVAP occlusion model was constructed by filling the catheter with swine blood and incubating it at 37.5°C. The model was incubated for different lengths of time ranging from 1 day to 7 days. Each incubation time point included 20 ports. Total catheter occlusion of the TIVAPs was assessed with a 10-mL saline syringe equipped with a non-coring needle. Occlusion was defined as no passage of saline through the catheter when it was aspirated and infused gently with the 10-mL saline syringe. Pressure was evaluated during recanalization with an indeflator. Histological examination was performed on the clot obtained during recanalization. Among the 140 total experimental ports, 65 occlusions (46.4%) were detected. Of these 65 occlusions, 56 (86.1%) were recanalized by mechanical saline pressure via the indeflator. The indeflator pressure ranged from 29 pound per square-inch (psi) to 265 psi at mechanical catheter recanalization (mean: 110 psi). Histologically, all specimens from the model ports exhibited a similar appearance; specifically, erythrocytes, cells, and fibrin were evenly scattered throughout the clot. Our data indicate that it is feasible to generate a TIVAP clot occlusion model with swine blood. Moreover, mechanical recanalization was suitable for resolving occluded catheters without thrombolytic agents.

Multiparametric Magnetic Resonance Imaging for Prediction of Parenchymal Hemorrhage in Acute Ischemic Stroke After Reperfusion Therapy.

Background and Purpose—Patients with acute ischemic stroke are at increased risk of developing parenchymal hemorrhage (PH), particularly in the setting of reperfusion therapies. We have developed a predictive model to examine the risk of PH using combined magnetic resonance perfusion and diffusion parameters, including cerebral blood volume (CBV), apparent diffusion coefficient, and microvascular permeability (K2).Methods—Voxel-based values of CBV, K2, and apparent diffusion coefficient from the ischemic core were obtained using pretreatment magnetic resonance imaging data from patients enrolled in the MR RESCUE clinical trial (Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy). The associations between PH and extreme values of imaging parameters were assessed in univariate and multivariate analyses. Receiver-operating characteristic curve analysis was performed to determine the optimal parameter(s) and threshold for predicting PH.Results—In 83 patients included in this analysis, 20 developed PH. Univariate analysis showed significantly lower 10th percentile CBV and 10th percentile apparent diffusion coefficient values and significantly higher 90th percentile K2 values within the infarction core of patients with PH. Using classification tree analysis, the 10th percentile CBV at threshold of 0.47 and 90th percentile K2 at threshold of 0.28 resulted in overall predictive accuracy of 88.7%, sensitivity of 90.0%, and specificity of 87.3%, which was superior to any individual or combination of other classifiers.Conclusions—Our results suggest that combined 10th percentile CBV and 90th percentile K2 is an independent predictor of PH in patients with acute ischemic stroke with diagnostic accuracy superior to individual classifiers alone. This approach may allow risk stratification for patients undergoing reperfusion therapies.Clinical Trial Registration—URL: https://www.clinicaltrials.gov. Unique identifier: NCT00389467.

Abstract WP140: Imaging of Clot Porosity Prior to Endovascular Thrombectomy

Background: Clot characteristics and porosity at the proximal portion of an arterial occlusion may influence potential recanalization. Thrombus permeability may be a factor in intravenous thrombolysis, whereas such features of clots prior to endovascular thrombectomy remains largely unexplored. We developed a technique to image clot porosity and yield quantitative measures that may predict mechanical recanalization. Methods: Consecutive cases of large artery occlusion (ICA or proximal M1 MCA) with single-phase CT angiography (CTA) acquired immediately prior to endovascular thrombectomy were analyzed. 3D-reconstruction, vessel segmentation, centerline extraction, signal intensity gradient calculations and surface mapping of CTA yielded porosity images and quantitative measures. Porosity measures were correlated with angiography parameters and procedural details. Results: 53 consecutive cases of acute stroke with contemporaneous sCTA and DSA were used to generate porosity images. Technical limitations precluded image processing in 9 cases, due to diminished contrast conspicuity in close proximity to bone interfaces. Porosity features on resulting images and the quantitative measures of clot penetration varied markedly, even within the subset of M1 or ICA occlusions, respectively. The occlusions often exhibited long segments (mean 18 ± 11 mm) of luminal narrowing before complete occlusion. Current analyses examine whether higher porosity or greater proximal contrast penetration of the clot is associated with faster recanalization and fewer device passes during endovascular thrombectomy. Conclusions: Clot porosity images and quantitative measures of proximal contrast penetration may be generated from routine CTA. Imaging of clot porosity may be a useful adjunct in planning of endovascular procedures and future strategies may focus on distinguishing atherosclerotic versus thromboembolic large artery occlusions.

Abstract TP27: Impact of Mechanical Thrombectomy Device on the Thrombus Histology in Acute Embolic Stroke

Background and Purpose: Thrombus composition has been suggested to have a decisive impact on the outcome of patients treated by mechanical thrombectomy because of embolic stroke. The aim of this prospective study was to assess the impact of a mechanical thrombectomy device (Penumbra aspiration catheter vs. Stent retriever) on thrombus composition, which could affect flow impairment after reperfusion. Methods: Thrombi of consecutive stroke patients with large vessel occlusion were collected during intracranial mechanical recanalization. Mechanical thrombectomy device was used either Penumbra aspiration catheter or Stent retriever. The hematoxylin and eosin-stained specimens were quantitatively analyzed in terms of the relative fractions of the main constituents (red blood cells and fibrin/platelets). Results: Of 65 cardio-embolic patients, Penumbra aspiration catheter was used in 27 patients, and Stent retriever was used in 38 patients. There was no significance in age, sex, occlusion vessel, NIH stroke scale, and onset to reperfusion time. The volume of thrombi was significantly larger in Penumbra group compared with that in Stent group (3.68 cm3 vs. 0.95 cm3, P&lt;0.01). On the other hand, The percentage of fibrin component was significantly higher in Stent group (36.2% vs. 62.4%, P&lt;0.01). Preoperative IV-tPA reduced the size of thrombi in Stent group, which was not seen in Penumbra group (0.46 cm3 vs. 1.26 cm3, P&lt;0.01). Interestingly, preoperative susceptibility vessel sign on MR imaging correlated with the percentage of red blood cells in not Stent group but Penumbra group. Finally, new infarction on MR imaging was not different between two groups 24 hours after the treatment. Conclusions: Stent retriever could crush thrombus and reduce its size, which induce distal migration of the red blood cell component. However, it did not affect the final infarct lesion and outcome.

Current status and prospects of endovascular mechanical thrombectomy for treatment of acute ischemic stroke

Acute ischemic stroke has already become common cause of death in our country. Until now, the intravenous thrombolysis therapy produces a limited therapeutic efficacy in patients with acute ischemic stroke, because the recanalization rate is very low in patients with large vessel occlusion, especially with interal carotid artery occlusion. As a novel modality of primary treatment, endovascular mechanical recanalization using clot removal has become a noticeably efficient intervention and a hot research focus of acute ischemic stroke. In this paper, we reviewed recent large multicenter trials of endovascular mechanical recanalization in the world. Key words: Acute ischemic stroke; Large-vessel occlusion; Endovascular treatment; Stent

Treatment protocol based on assessment of clot quality during endovascular thrombectomy for acute ischemic stroke using the Trevo stent retriever.

The optional endovascular approach for acute ischemic stroke is unclear. The Trevo stent retriever can be used as first-line treatment for fast mechanical recanalization. The authors developed a treatment protocol for acute ischemic stroke based on the assessment of clot quality during clot removal with the Trevo. This prospective single-center study included all patients admitted for acute ischemic stroke between July 2014 and February 2015, who underwent emergency endovascular treatment. According to the protocol, the Trevo was used for first-line treatment. Immediately after the Trevo was deployed, the stent delivery wire was pushed to open the stent by force (ACAPT technique). Clot quality was assessed on the basis of the perfusion status after deployment of the Trevo; continued occlusion or immediate reopening either reoccluded or maintained after the stent retriever had been in place for 5 min. If there was no obvious clot removal after the first pass with the Trevo, according to the quality of the clot, either a second pass was performed or another endovascular device was selected. Twelve consecutive patients with acute major cerebral artery occlusion were analyzed. Thrombolysis in cerebral infarction score 2b and 3 was achieved in 11 patients (91.7%) and 9 (75%) had a good clinical outcome after 90 days based on a modified Rankin scale score ≤ 2. Symptomatic intracranial hemorrhage occurred in 1 patient (8.3%). The overall mortality rate was 8.3%. Endovascular thrombectomy using the Trevo stent retriever for first-line treatment is feasible and effective.

Thrombus Histology Suggests Cardioembolic Cause in Cryptogenic Stroke.

Ischemic stroke of undetermined cause is a major health issue because of its high frequency and clinical relevance. Histopathologic analysis of human thrombi, retrieved from stroke patients with large-vessel occlusion during mechanical thrombectomy, may provide information about underlying pathologies. This study examines the relationship between stroke causes and histological clot composition to identify specific patterns that might help to distinguish causes of cryptogenic stroke. Thrombi of 145 consecutive stroke patients with large-vessel occlusion were collected during intracranial mechanical recanalization. The hematoxylin and eosin-stained specimens were quantitatively analyzed in terms of the relative fractions of the main constituents (red and white blood cells and fibrin/platelets). These data, along with additional clinical and interventional parameters, were compared for different stroke subtypes, as defined by the international Trial of Org 10172 in Acute Stroke Treatment criteria. The composition of thrombi from cardioembolic and noncardioembolic stroke patients differed significantly for all main thrombus components. Cardioembolic thrombi had higher proportions of fibrin/platelets (P=0.009), less erythrocytes (P=0.003), and more leucocytes (P=0.035) than noncardioembolic thrombi. Cryptogenic strokes showed strong overlap with cardioembolic strokes but not with noncardioembolic strokes, in terms of both thrombus histology and interventional and clinical outcome parameters. Quantitative evaluation of thrombus composition may help to distinguish between different stroke causes. Our findings support the notion that the majority of cryptogenic strokes are cardioembolic.