Vessel Recanalization Research Articles

Immunothrombosis in Acute Ischemic Stroke.

Ischemic stroke is one of the leading causes of disability and mortality worldwide. Thrombosis is the main pathological process of stroke and is therefore an important therapeutic target in stroke prevention. In recent years, with the development of endovascular treatment and therefore retrieving the thrombus for further investigation, evidence is accumulating that immune cells are inextricably linked to stroke pathogenesis. Circulating immune cells have been found to induce immunothrombosis, and they actively participate in the formation of the thrombus by promoting platelet recruitment and thrombin activation. Additionally, the formation of thromboinflammation leads to increased instability of atherosclerotic plaques. We review the concepts of stroke immunothrombosis and thromboinflammation and the effect of immune cells on vessel recanalization and patient outcome. In addition, we elaborate on the possible mechanism of immune cells being activated and participating in thrombosis in ischemic stroke.

Retinal Vasculopathy and Choroiditis after Pegcetacoplan Injection: Clinicopathologic Support for a Drug Hypersensitivity Reaction

PurposeTo report the detailed histopathology of two enucleated eyes from two patients who developed severe visual loss associated with retinal hemorrhages, vessel sheathing and vascular nonperfusion after administration of an initial dose of intravitreal pegcetacoplan, and to propose, with supportive histopathology, the pathogenesis of the clinical syndrome previously termed hemorrhagic occlusive retinal vasculitis (HORV). DesignCase series. SubjectsTwo enucleated eyes from two patients treated with intravitreal pegcetacoplan. MethodsRetrospective, multicenter consecutive clinical-pathologic analysis. Main Outcome MeasuresHistopathologic review and immunophenotypic characterization. ResultsBoth patients presented with inflammation and significant vision loss nine days following the initial injection of pegcetacoplan with no subsequent improvement and underwent enucleation for pain control. Histologic examination of the enucleated eyes (patient one at 4 months post-injection and patient two at 40 days) revealed extensive vascular thrombosis, retinal hemorrhages and necrosis, and a dense inflammatory infiltrate in the uvea and variably the optic nerve, episclera, and muscle tendons composed of predominantly of T-cells, macrophages, and eosinophils. Notably, the inflammatory infiltrate was absent from the retina. In addition, one eye demonstrated multiple foci of glomerular-like vascular proliferations in the uveal tract and thrombosis with focal recanalization of vessels in the optic nerve. ConclusionDrug-induced, immune-mediated, retinal vasculopathy and choroiditis (DIRVAC) is a rare complication following pegcetacoplan injection. Although some limitations arise in interpretation of histopathologic findings due to compensatory changes in the eyes over time (prior to enucleation), the authors propose that the combined clinical, histopathologic, and immunohistochemical findings suggest a mixed-type, delayed hypersensitivity reaction as mechanism of initial injury.

Pulsed focused ultrasound ablation assisted by a surface modified catheter for thrombolysis: a feasibility study

Interventional procedures for the recanalization of blood vessels to treat deep vein thrombosis carry a high risk of vessel wall injuries or hemorrhaging. Focused ultrasound (FUS) has been used to non-invasively break down blood clots that occlude the vessels in both in vitro and in vivo studies. Previous studies have either used thrombolytic drugs or ultrasound contrast agents (e.g., microbubbles) in combination with FUS. Several studies have applied very high peak-negative-pressures (PNP) during FUS treatment to achieve successful thrombolysis without the use of contrast agents. In the current study, we demonstrated that cavitation activity could be significantly enhanced by placing a nitinol wire, whose surface was roughed by laser etching, in the focal region of a FUS field. We demonstrated in vitro in a mock thrombosis that the thrombolysis efficacy of a 500 kHz FUS transducer was significantly enhanced using a surface-etched nitinol wire as compared to an unetched nitinol wire, whereas FUS-alone at the same pressure level did not result in any thrombolysis. These results suggest that a surface modified nitinol catheter exposed to FUS can result in intense cavitation activities leading to enhanced thrombolysis without the use of additional pharmacological or contrast agents.

A hyper-viscoelastic uniaxial characterization of collagenous embolus analogs in acute ischemic stroke

PurposeAcute ischemic stroke is a leading cause of death and morbidity worldwide. Despite advances in medical technology, nearly 30% of strokes result in incomplete vessel recanalization. Recent studies have demonstrated that clot composition correlates with success rates of mechanical thrombectomy procedures. To understand clot behavior during thrombectomy, which exerts considerable strains on thrombi, in vitro studies must characterize the rate-dependent high-strain behavior of embolus analogs (EAs) with different formation conditions, which can be used to fit models of hyper-viscoelasticity. MethodsIn this study, the effect of collagen infiltration as a carotid-induced collagen-rich thrombosis surrogate is considered as a contributor to embolus analog high-strain stiffness, when compared to 40% hematocrit EAs. ResultsEA high-strain stiffnesses, characterized on a uniaxial load frame, increase by an order of magnitude for collagenous clot analogs. Chandler loop analogs show high-strain stiffnesses and clot compositions commensurate with previous reports of stroke patient clots, and collagenous clots show significant increase in stiffness when compared to stroke patient clots. Finally, hyper-viscoelastic curve fitting demonstrates the asymmetry between tension and compression. Nonlinear, rate-dependent models that consider clot-stiffening behavior match the high strain stiffness of clots fairly well. Furthermore, we demonstrate that the stability of the elastic energy needs to be considered to obtain optimal curve fits for high-strain, rate dependent data. ConclusionThis study provides a framework for the development of dynamically formed EAs that mimic the mechanical and structural properties of in vivo clots and provides parameters for numerical simulation of clot behavior with hyper-viscoelastic models.

Age-related differences in diffusion-weighted imaging lesion volume and reversal in patients with successful recanalization after mechanical thrombectomy

BackgroundWith the advancement of mechanical thrombectomy (MT), post-treatment diffusion-weighted imaging (DWI) lesion reversal (DWIR) has been reported. This study aimed to compare the volumes of DWI lesions and the frequencies...

Safety, feasibility and efficacy of sonothrombolysis with micro boluses of perfluoropropane as a point of care therapy for patients with acute ST-elevation myocardial infarction.

Despite advances in timely revascularisation of ST elevation myocardial infarction (STEMI) patients, there are several practical and unavoidable delays. Sonothrombolysis (administered during micro boluses of Perfluoropropane) initiated bedside as a point-of-care therapy during the initial evaluation of the patient may potentially mitigate this by producing early culprit vessel revascularisation. This was a prospective, single-centre study on hemodynamically stable patients presenting within 12 hours of a first STEMI who consented for study participation. Fifteen patients were recruited over a 1-month period. Eleven were male. Nine patients had anterior wall STEMI and left anterior descending as culprit vessel. There were no significant changes in safety outcomes. Median First Medical Contact (FMC)-Sono time was 12 min (10-15). Median duration of sonothrombolysis was 14 min (12-16). FMC-device time was 97 min (79-128). Six patients had culprit vessel recanalisation before primary percutaneous coronary intervention (PPCI) which was consistent with the reference rates of therapy-associated recanalisation (p = 0.535). Micro bolus sonothrombolysis maybe safely initiated as a point of care therapy adjunctive to PPCI in hemodynamically stable STEMI patients with reasonable efficacy. Further randomised trials are needed to ascertain its applicability in various geographical and clinical settings.

Rates and Impact of Serious Adverse Events after Endovascular Thrombectomy among Large Vessel Occlusion Stroke Patients.

Complications or serious adverse events (SAEs) are common in the treatment of patients with large vessel occlusion stroke. There has been limited study of the impact of SAEs for patients after endovascular thrombectomy (EVT). The goal of this study was to characterize the rates and clinical impact of SAEs following EVT. A post hoc analysis was performed using pooled databases of the "DEVT" and "RESCUE BT" trials. SAEs were designated as symptomatic intracranial hemorrhage, brain herniation or craniectomy, respiratory failure, circulatory failure, pneumonia, deep venous thrombosis, and systemic bleeding. The primary endpoint was functional independence (modified Rankin scale score 0-2 within 90 days). Logistic regression analysis was used to determine the predictors and associations between SAEs and outcomes. Of 1,182 enrolled patients, 402 (34%) had a procedural complication and 745 (63%) had 1,404 SAE occurrences with 4.65% in-hospital mortality. The three most frequent SAEs were pneumonia (620, 52.5%), systemic bleeding (174, 14.7%), and respiratory failure (173, 14.6%). Pneumonia, systemic bleeding, or deep venous thrombosis was less life-threatening. Patients with advanced age (adjusted odds ratio, 1.28 [95% confidence interval, 1.14-1.43]), higher NIHSS (1.09 [1.06-1.11]), occlusion site (middle cerebral artery-M1 vs. internal carotid artery [ICA]: 0.75 [0.53-1.04]; M2 vs. ICA: 1.30 [0.80-2.12]), longer procedure time (1.01 [1.00-1.01]), and unsuccessful vessel recanalization (1.79 [1.06-2.94]) were more likely to experience SAEs. Compared with no SAE, patients with SAEs had lower odds of functional independence (0.46 [0.40-0.54]). Overall, SAEs diagnosed following thrombectomy in patients with stroke were common (more than 60%) and associated with functional dependence. Patients with advanced age, higher NIHSS, longer procedure time, and failed recanalization were more likely to experience SAEs. There was no statistical difference in the risk of SAEs among patients with M1 and M2 occluded compared with those ICA occluded. An understanding of the prevalence and predictors of SAEs could alert clinicians to the estimated risk of an SAE for a patient after EVT.

Overestimation of the Ischemic Core Is Associated With Higher Core Lesion Volume and Degree of Reperfusion After Thrombectomy.

Background CT perfusion (CTP)-derived baseline ischemic core volume (ICV) can overestimate the true extent of infarction, which may result in exclusion of patients with ischemic stroke from endovascular treatment (EVT). Purpose To determine whether ischemic core overestimation is associated with larger ICV and degree of recanalization. Materials and Methods This retrospective multicenter cohort study included patients with acute ischemic stroke triaged at multimodal CT who underwent EVT between January 2015 and January 2022. The primary outcome was ischemic core overestimation, which was assumed when baseline CTP-derived ICV was larger than the final infarct volume at follow-up imaging. The secondary outcome was functional independence defined as modified Rankin Scale scores of 0-2 90 days after EVT. Successful vessel recanalization was defined as extended Thrombolysis in Cerebral Infarction score of 2b or higher. Categorical variables were compared between patients with ICV of 50 mL or less versus large ICV greater than 50 mL with use of the χ2 test. Adjusted multivariable logistic regression analyses were used to assess the primary and secondary outcomes. Results In total, 721 patients (median age, 76 years [IQR, 64-83 years]; 371 female) were included, of which 162 (22%) demonstrated ischemic core overestimation. Core overestimation occurred more often in patients with ICV greater than 50 mL versus 50 mL or less (48% vs 16%; P < .001) and those with successful versus unsuccessful vessel recanalization (26% vs 13%; P < .001). In an adjusted model, successful recanalization after EVT (odds ratio [OR], 3.14 [95% CI: 1.65, 5.95]; P < .001) and larger ICV (OR, 1.03 [95% CI: 1.02, 1.04]; P < .001) were independently associated with core overestimation, while the time from symptom onset to imaging showed no association (OR, 0.99; P = .96). Core overestimation was independently associated with functional independence (adjusted OR, 2.83 [95% CI: 1.66, 4.81]; P < .001) after successful recanalization. Conclusion Ischemic core overestimation occurred more frequently in patients presenting with large CTP-derived ICV and successful vessel recanalization compared with those with unsuccessful recanalization. © RSNA, 2024 Supplemental material is available for this article.

Safety and efficacy of anticoagulant treatment in patients with ovarian vein thrombosis: a systematic review and meta-analysis of observational studies

BackgroundThe role of anticoagulation in ovarian vein thrombosis (OVT) is uncertain. ObjectivesWe aimed to evaluate safety and efficacy of anticoagulant treatment in OVT patients. MethodsA systematic search was conducted in MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases up to April 2024. Eligible studies included randomized controlled trials and observational studies enrolling at least 10 adult patients with objectively diagnosed OVT and treated with any anticoagulants. The protocol was prospectively registered in the International Prospective Register of Systematic Reviews (CRD42021270883). ResultsWe included 17 observational studies (621 anticoagulated and 376 nonanticoagulated OVT patients); 9 studies enrolled mainly pregnancy/puerperium-related OVT. Most patients received heparins alone (45.7%) or proceeded to vitamin K antagonists (39.2%). The average treatment duration was ≤3 months in 8 studies (47.1%), >3 to ≤6 months in 6 studies (35.3%), and >6 months in 3 studies (17.6%). In treated patients, mortality rate was 2.43% (95% CI, 0.54%-5.41%; I2 = 53.8%; 12/406 patients; 13 studies), major bleeding was 1.27% (95% CI, 0.48%-2.38%; I2 = 2.5%; 7/583 patients; 15 studies), recurrent venous thromboembolism (VTE) was 3.49% (95% CI, 1.12%-6.95%; I2 = 63.5%; 22/482 patients; 15 studies), and vessel recanalization was 89.4% (95% CI, 74.6%-98.6%; I2 = 80.6%; 163/184 patients; 8 studies). The rate of recurrent VTE in untreated patients was 8.65% (95% CI, 2.61%-17.35%); however, the difference compared with treated patients was not statistically significant (risk ratio, 0.70; 95% CI, 0.36-1.37). At subgroup analyses, the rates of major bleeding and recurrent VTE were 0.80% (95% CI, 0.0-2%.17%) and 3.81% (95% CI, 0.42%-9.63%) in pregnancy/puerperium-related OVT, respectively, and 1.12% (95% CI, 0.32%-2.34%) and 1.78% (95% CI, 0.62%-3.46%), respectively, when analyzing only full-text studies. ConclusionThere is paucity of literature regarding OVT. Our results suggest that anticoagulation is associated with low rates of major bleeding and recurrent VTE.

Insights into Angiographic Recanalization of Large Arterial Occlusion: Institutional Experience with Mechanical Thrombectomy for Acute Ischemic Stroke.

Stroke is a leading cause of morbidity and mortality in humans. Most strokes are ischemic in nature and early recanalization of occluded vessels determines good outcomes. Recanalization of occluded vessels depends on many angiographic and demographic features. These factors need to be identified for better patient overall outcomes. Better preoperative knowledge of factors can help in customizing our treatment approach and explaining the prognosis to the guardians of the patients. We aim to share our institutional experience with mechanical thrombectomy (MT) for stroke and studied factors that affect an angiographic recanalization of vessels . A retrospective single-center study was conducted involving 104 patients who underwent MT at our institution between January 2016 and December 2019. Patient demographics, baseline characteristics, pre- and postprocedural imaging findings, and other clinical data were meticulously reviewed. We divided patients into successful recanalization (modified thrombolysis in cerebral ischemia [mTICI] 2b or 3) and unsuccessful recanalization (mTICI 2a or 1) groups and various factors were analyzed to evaluate their impact on recanalization rates. In the univariate analysis, a significant association was observed between successful recanalization and several factors: the absence of rheumatic heart disease (RHD) as a risk factor ( p = 0.035), the presence of a hyperdense vessel sign ( p = 0.003), and the use of treatment methods including aspiration ( p = 0.031), stent retriever ( p = 0.001), and Solumbra ( p = 0.019). However, in the multivariate analysis, none of these factors exhibited statistical significance. The presence of RHD is a risk factor associated with poor angiographic recanalization in all three MT treatment modalities. Based on the above variables we can guide the patients/relatives prior to MT procedure for their better outcome and risk-benefit ratio.

Association between Transient-Continuous Hypotension during Mechanical Thrombectomy for Acute Ischemic Stroke and Final Infarct Volume in Patients with Proximal Anterior Circulation Large Vessel Occlusion.

Background/Objectives: Periprocedural blood pressure changes in stroke patients with a large vessel occlusion are a known modifiable risk factor of unfavorable treatment outcomes. We aimed to evaluate the association between pre-revascularization hypotension and the final infarct volume. Methods: In our retrospective analysis, we included 214 consecutive stroke patients with an anterior circulation large vessel occlusion that underwent mechanical thrombectomy under general anesthesia. Noninvasively obtained blood pressure values prior to symptomatic vessel recanalization were analyzed as a predictor of post-treatment infarct size. Linear logistic regression models adjusted for predefined factors were used to investigate the association between blood pressure parameters and the final infarct volume. Results: In our cohort, higher baseline systolic blood pressure (aβ = 8.32, 95% CI 0.93-15.7, p = 0.027), its maximal absolute drop (aβ = 6.98, 95% CI 0.42-13.55, p = 0.037), and >40% mean arterial pressure decrease (aβ = 41.77, CI 95% 1.93-81.61, p = 0.040) were independently associated with higher infarct volumes. Similarly, continuous hypotension measured as intraprocedural cumulative time spent below either 100 mmHg (aβ = 3.50 per 5 min, 95% CI 1.49-5.50, p = 0.001) or 90 mmHg mean arterial pressure (aβ = 2.91 per 5 min, 95% CI 0.74-5.10, p = 0.010) was independently associated with a larger ischemia size. In the subgroup analysis of 151 patients with an M1 middle cerebral artery occlusion, two additional factors were independently associated with a larger ischemia size: systolic blood pressure maximal relative drop and >40% drop from pretreatment value (aβ = 1.36 per 1% lower than baseline, 95% CI 0.04-2.67, p = 0.043, and aβ = 43.01, 95% CI 2.89-83.1, p = 0.036, respectively). No associations between hemodynamic parameters and post-treatment infarct size were observed in the cohort of intracranial internal carotid artery occlusion. Conclusions: In patients with ischemic stroke due to a proximal middle cerebral artery occlusion, higher pre-thrombectomy treatment systolic blood pressure is associated with a larger final infarct size. In patients treated under general anesthesia, hypotension prior to the M1 portion of middle cerebral artery recanalization is independently correlated with the post-treatment infarct volume. In this group, every 5 min spent below the mean arterial pressure threshold of 100 mmHg is associated with a 4 mL increase in ischemia volume on a post-treatment NCCT. No associations between blood pressure and final infarct volume were present in the subgroup of patients with an intracranial internal carotid artery occlusion.

Predictors of Futile Recanalization in Ischemic Stroke Patients with low baseline NIHSS.

There is yet no randomized controlled evidence that mechanical thrombectomy (MT) is superior to best medical treatment in patients with large vessel occlusion but minor stroke symptoms (National Institutes of Health Stroke Scale [NIHSS] <6). Prior studies of patients with admission NIHSS scores >6 observed unfavorable functional outcomes despite successful recanalization, commonly termed as futile recanalization (FR), in up to 50% of cases. The aim of this study is to determine the prevalence of FR in patients with minor stroke and identify associated patient-specific risk factors. Our multicenter cohort study screened all patients prospectively enrolled in the German Stroke Registry Endovascular Treatment from 2015 to 2021 (n=13082). Included were patients who underwent MT for anterior circulation vessel occlusion with a baseline NIHSS score of <6 and successful recanalization (modified Thrombolysis in Cerebral Infarction [mTICI] score of 2b-3). FR was defined by a modified Rankin Scale (mRS) score of 2-6 at 90 days. Multivariable logistic regression analysis was conducted to explore factors associated with FR. A total of 674 patients met the inclusion criteria. FR occurred in 268 (40%) patients. Multivariable logistic regression analysis indicates that higher age (adjusted odds ratio: 1.04 [95% confidence interval: 1.02-1.06]), pre-stroke mRS 1 (aOR: 2.70 [1.51-4.84]), transfer from admission hospital to comprehensive stroke center (aOR: 1.67 [1.08-2.56]), longer time from symptom onset/last seen well to admission (aOR: 1.02 [1.00-1.04]), MT under general anesthesia (aOR: 1.78 [1.13-2.82]), higher NIHSS after 24 hours (aOR: 1.09 [1.05-1.14]), and symptomatic intracranial hemorrhage (aOR: 16.88 [2.03-140.14]) increased the odds of FR. There was no significant difference in primary outcome between achieving mTICI 2b or 3. Unfavorable functional outcomes despite successful vessel recanalization were frequent in acute ischemic stroke patients with low NIHSS scores on admission. We provide patient-specific risk factors that indicate an increased risk of FR and should be considered when treating patients with minor stroke. The data that support the findings of our study are available on reasonable request after approval of the GSR steering committee.

Investigating the potential of catheter-assisted pulsed focused ultrasound ablation for atherosclerotic plaques.

Atherosclerosis is a condition in which an adhesive substance called plaque accumulates over time inside the arteries. Plaque buildup results in the constriction of arteries, causing a shortage of blood supply to tissues and organs. Removing atherosclerotic plaques controls the development of acute ischemic stroke and heart diseases. It remains imperative for positive patient outcomes. This study sought to develop a minimally invasive technique for removing arterial plaques by applying focused ultrasound (FUS) energy on the metal surface of a nitinol catheter wire to induce inertial cavitation. The induced cavitation can deplete plaque mechanically inside the arteries, leading towards improved recanalization of blood vessels. The enhanced cavitation effect induced by combining FUS with a metal catheter was first verified by exposing agar phantom gels with or without a 0.9-mm diameter nitinol wire to an acoustic field produced by a 0.5-MHz FUS transducer. The phenomenon was further confirmed in pork belly fat samples with or without a 3-mm diameter nitinol catheter wire. Cavitation was monitored by detecting the peaks of emitted ultrasound signals from the samples using a passive cavitation detector (PCD). Cavitation threshold values were determined by observing the jump in the peak amplitude of signals received by the PCD when the applied FUS peak negative pressure (PNP) increased. To simulate arterial plaque removal, FUS with or without a catheter was used to remove tissues from pork belly fat samples and the lipid cores of human atherosclerotic plaque samples using 2500-cycle FUS bursts at 10% duty cycle and a burst repetition rate of 20Hz. Treatment outcomes were quantified by subtracting the weight of samples before treatment from the weight of samples after treatment. All measurements were repeated 5 times (n=5) unless otherwise indicated, and paired t-tests were used to compare the means of two groups. A p-value of <0.05 will be considered significant. Our results showed that with a nitinol wire, the cavitation threshold in agar phantoms was reduced to 2.6MPa from 4.3MPa PNP when there was no nitinol wire in the focal region of FUS. For pork belly fat samples, cavitation threshold values were 1.0 and 2.0MPa PNP, with and without a catheter wire, respectively. Pork belly fat tissues and lipid cores of atherosclerotic plaques were depleted at the interface between a catheter and the samples at 2 and 4MPa FUS PNP, respectively. The results showed that with a catheter wire in the focal region of a 3-min FUS treatment session, 24.7 and 25.6mg of lipid tissues were removed from pork belly fat and human atherosclerotic samples, respectively. In contrast, the FUS-only group showed no reduction in sample weight. The differences between FUS-only and FUS-plus-catheter groups were statistically significant (p<0.001 for the treatment on pork belly samples, and p<0.01 for the treatment on human atherosclerotic samples). This study demonstrated the feasibility of catheter-assisted FUS therapy for removing atherosclerotic plaques.

Enhanced Prediction of Malignant Cerebral Edema in Large Vessel Occlusion with Successful Recanalization Through Automated Weighted Net Water Uptake

Malignant cerebral edema (MCE) is associated with both net water uptake (NWU) and infarct volume. We hypothesized that NWU weighted by the affected Alberta Stroke Program Early Computed Tomography Score (ASPECTS) regions could serve as a quantitative imaging biomarker of aggravated edema development in acute ischemic stroke with large vessel occlusion (LVO). The aim of this study was to evaluate the performance of weighted NWU (wNWU) to predict MCE in patients with mechanical thrombectomy (MT). We retrospectively analyzed consecutive patients who underwent MT due to LVO. NWU was computed from nonenhanced computed tomography scans upon admission using automated ASPECTS software. wNWU was derived by multiplying NWU with the number of affected ASPECTS regions in the ischemic hemisphere. Predictors of MCE were assessed through multivariate logistic regression analysis and receiver operating characteristic curves. NWU and wNWU were significantly higher in MCE patients than in non-MCE patients. Vessel recanalization status influenced the performance of wNWU in predicting MCE. In patients with successful recanalization, wNWU was an independent predictor of MCE (adjusted odds ratio 1.61; 95% confidence interval [CI] 1.24-2.09; P<0.001). The model integrating wNWU, National Institutes of Health Stroke Scale, and collateral score exhibited an excellent performance in predicting MCE (area under the curve 0.80; 95% CI 0.75-0.84). Among patients with unsuccessful recanalization, wNWU did not influence the development of MCE (adjusted odds ratio 0.99; 95% CI 0.60-1.62; P=0.953). This study revealed that wNWU at admission can serve as a quantitative predictor of MCE in LVO with successful recanalization after MT and may contribute to the decision for early intervention.

An Institutional Perspective on the Number of Stent Retriever Pass and Rate of Recanalization in Mechanical Thrombectomy for Acute Ischemic Stroke: When to Stop?

Mechanical thrombectomy is the standard treatment modality for flow restoration in acute ischemic stroke. In cases of persistent occlusion, the optimal number of retrieval attempts before considering procedure termination is currently undetermined and is a topic for research. Therefore in this study, we studied the impact of the number of stent retrieval maneuvers on the recanalization of vessels. In this retrospective single-center observational study we included 52 patients with large vessel occlusion who underwent stent retriever mechanical thrombectomy. Successful recanalization rate was defined as modified TICI (Thrombolysis in Cerebral Infarction) 2b or 3. The overall successful recanalization rate was 44.24%. The recanalization rate per stent retrieval attempt was the highest in 1st attempt (28.84%) and no recanalization was observed with the 3rd, 5th, and 6th attempts (p<0.001). At most 6 retrieval attempts were used. After two retrieval attempts, 91% of the patients were successfully recanalized and other after the 5th attempt could not result in recanalization.

Thrombectomy in ischemic stroke patients with large core but minor ischemic changes on non-enhanced computed tomography.

The Alberta Stroke Program Early CT Score (ASPECTS) is regularly used to guide patient selection for mechanical thrombectomy (MT). Similarly, penumbral imaging based on computed tomography perfusion (CTP) may serve as neuroimaging tool to guide treatment. Yet, patients with a large ischemic core on CTP may show only minor ischemic changes resulting in a high ASPECTS. We hypothesized twofold: (1) the treatment effect of vessel recanalization in patients with core volume > 50 mL but ASPECTS ⩾ 6 is not different compared to high ASPECTS patients with core volume < 50 mL, and (2) recanalization is associated with core overestimation. We conducted an observational study analyzing ischemic stroke patients consecutively treated with MT after triage by multimodal CT. Functional endpoint was the rate of functional independence at Day 90 defined as modified Rankin Scale (mRS) 0-2. Imaging endpoint was core overestimation, which was considered when CTP-derived core was larger than the final infarct volume assessed on follow-up imaging. Recanalization was evaluated with the extended Thrombolysis in Cerebral Infarction (eTICI) scale. Multivariable logistic regression analysis and propensity score matching (PSM) were used to assess the association of recanalization (eTICI ⩾ 2b) with functional outcome and core overestimation. Of 630 patients with ASPECTS ⩾ 6, 91 patients (14.4%) had a large ischemic core. Following 1:1 PSM, the treatment effect of recanalization was not different in patients with large core and ASPECTS ⩾ 6 (+ 25.8%, 95% CI: 16.3-35.4, p < 0.001) compared to patients with ASPECTS ⩾ 6 and core volume < 50 mL (+ 14.9%, 95% CI: 5.7-24.1, p = 0.002). Recanalization (aOR: 3.46, 95% CI: 1.85-6.47, p < 0.001) and higher core volume (aOR: 1.03, 95% CI: 1.02-1.04, p < 0.001) were significantly associated with core overestimation. In patients with ASPECTS ⩾ 6, core volumes did not significantly modify outcomes following recanalization. Reperfusion and higher core volume were significantly associated with core overestimation which may explain the treatment effect of MT for patients with a large ischemic core but minor ischemic changes on non-enhanced CT. The data analyzed in this study will be available and shared on reasonable request from any qualified researcher for the purpose of replicating the results after clearance by the local ethics committee.

Recent Advances in Bioinspired Soft Robots: Fabrication, Actuation, Tracking, and Applications

AbstractNatural organisms offer a rich source for the construction of soft robots exhibiting autonomous and intelligent behaviors, encompassing attributes like motion, perception, and adaptability to environmental shifts. Drawing inspiration from these biological models, a multitude of soft robots have emerged, each distinguished by unique structures and functionalities enabling diverse actions, including swimming, crawling, swinging, walking, and tumbling. In this review, several soft robots and their motion modes from the perspective of specific native species are addressed. The actuation methods of soft robots are discussed, encompassing chemical, electrical, ultrasonic, optical, and magnetic actuation mechanisms. Furthermore, the application domains of soft robots, encompassing areas such as vessel recanalization, targeted drug delivery, cargo manipulation, and sensing are explored, providing a concise summary of their roles and potentials. The current challenges encountered in this research field are highlighted, and promising directions pertaining to soft robots are emphasized.

Impact of Total Ischemic Time on No Reflow Phenomenon

Background: Ischemic heart disease, particularly ST-segment elevation myocardial infarction (STEMI), remains a major cause of morbidity and mortality globally. Despite advancements in primary percutaneous coronary intervention (PPCI), the no-reflow phenomenon, characterized by inadequate myocardial reperfusion despite successful vessel recanalization, continues to pose significant challenges, affecting clinical outcomes adversely. Objective: This study aims to investigate the relationship between total ischemic time and the incidence of the no-reflow phenomenon in STEMI patients undergoing PPCI, to identify potential strategies for improving therapeutic outcomes. Methods: Conducted at Hayatabad Medical Complex, Peshawar, this retrospective cohort study included 160 STEMI patients treated over eight months (February to October 2022). We collected data on demographic characteristics, clinical presentation, and outcomes. Inclusion criteria were patients over 18 years, undergoing PPCI within 12 hours of symptom onset, without prior MI, severe bleeding disorders, or previous significant revascularization. Statistical analysis was performed using SPSS 25.0, considering P ≤0.05 as statistically significant. Results: The average total ischemic time was significantly longer in patients experiencing no-reflow (Group I, 7.91 hours) compared to those with normal reperfusion (Group II, 3.41 hours) (P=0.001). Group I also showed higher rates of cardiogenic shock (17.6% vs. 6.8%, P=0.012) and reinfarction (11.8% vs. 2.9%, P=0.010). Mortality was significantly higher in Group I (5.8% vs. 1.9%, P=0.020). Conclusion: Longer total ischemic time is associated with an increased risk of the no-reflow phenomenon and poorer clinical outcomes in STEMI patients. Reducing ischemic time could be crucial in improving reperfusion success and reducing complications post-PPCI.

Prediction of Futile Recanalization Following Mechanical Thrombectomy for Acute Ischemic Stroke Using Quantitative Electroencephalography: Temporal Delta/Alpha Power Ratio as an Independent Predictor

Objective: Previous studies have reported associations between quantitative electroencephalography (QEEG) parameters and acute ischemic stroke (AIS). However, the relationship between QEEG parameters and clinical outcomes in AIS patients with complete intracranial recanalization post-thrombectomy has been rarely explored. This study aims to evaluate the relationship between the QEEG parameter, specifically the regional delta/alpha power ratio (DAR), and futile recanalization (FR) in AIS patients with anterior circulation large vessel occlusion undergoing mechanical thrombectomy. Methods: A retrospective study was conducted on AIS patients with anterior circulation large artery occlusion who underwent mechanical thrombectomy and achieved complete vessel recanalization (mTICI 2b or 3) between May 2020 and October 2021. Patients with complete recanalization were categorized into effective recanalization and FR groups based on their modified Rankin scale (mRS) scores at three months. The FR group was defined as having an mRS score of 3–6 at three months, while the effective recanalization group had an mRS score of 0–2. Univariate analysis was performed to identify factors associated with FR, and factors with P &lt; 0.05 were further analyzed using binary logistic regression to determine independent predictors of FR. Receiver operating characteristic (ROC) curve analysis was employed to assess the predictive ability of identified factors for FR. Results: Among 152 patients, 81 had effective recanalization, while 71 had FR, resulting in an FR rate of 46.7%. Univariate analysis revealed that baseline characteristics such as admission NIH stroke scale (NIHSS) score, neutrophil ratio, hemorrhagic transformation rate, number of thrombectomy passes, and time to recanalization were higher, whereas ASPECTS score was lower in the FR group compared to the effective recanalization group, all with statistical significance (P &lt; 0.05). Electrophysiologically, DAR values in the affected frontal and temporal regions were significantly higher in the FR group compared to the effective recanalization group (P &lt; 0.05). After adjusting for potential confounders, multivariable adjusted regression analysis demonstrated that regional DAR (odds ratio [OR] 1.205 [95% CI 1.041–1.396], P = 0.013), neutrophil ratio (OR 1.040 [95% CI 1.040–1.081], P = 0.042), ASPECTS score (OR 0.556 [95% CI 0.397–0.780], P = 0.001), and admission NIHSS score (OR 1.209 [95% CI 1.064–1.373], P = 0.004) were independent predictors of FR. ROC analysis indicated that combining regional DAR, especially temporal DAR, with other clinical factors could effectively predict adverse outcomes. Conclusion: Baseline characteristics including NIHSS score, ASPECTS score, and neutrophil ratio are independent predictors of FR, while electrophysiological characteristics, particularly temporal DAR of regional DAR, are closely associated with adverse outcomes at three months post-mechanical thrombectomy in AIS patients with anterior circulation large vessel occlusion. This shows that models incorporating temporal DAR can effectively predict FR.

Advancements in research on the immune-inflammatory mechanisms mediated by NLRP3 inflammasome in ischemic stroke and the regulatory role of natural plant products.

Ischemic stroke (IS) is a major cause of mortality and disability among adults. Recanalization of blood vessels to facilitate timely reperfusion is the primary clinical approach; however, reperfusion itself may trigger cerebral ischemia-reperfusion injury. Emerging evidence strongly implicates the NLRP3 inflammasome as a potential therapeutic target, playing a key role in cerebral ischemia and reperfusion injury. The aberrant expression and function of NLRP3 inflammasome-mediated inflammation in cerebral ischemia have garnered considerable attention as a recent research focus. Accordingly, this review provides a comprehensive summary of the signaling pathways, pathological mechanisms, and intricate interactions involving NLRP3 inflammasomes in cerebral ischemia-reperfusion injury. Moreover, notable progress has been made in investigating the impact of natural plant products (e.g., Proanthocyanidins, methylliensinine, salidroside, α-asarone, acacia, curcumin, morin, ginsenoside Rd, paeoniflorin, breviscapine, sulforaphane, etc.) on regulating cerebral ischemia and reperfusion by modulating the NLRP3 inflammasome and mitigating the release of inflammatory cytokines. These findings aim to present novel insights that could contribute to the prevention and treatment of cerebral ischemia and reperfusion injury.