Per-pass analysis of recanalization and good neurological outcome in thrombectomy for stroke: Systematic review and meta-analysis

Risk Factors and Clinical Outcomes of Arterial Re-Occlusion After Successful Mechanical Thrombectomy for Emergent Intracranial Large Vessel Occlusion

Background: Re-occlusion of initially recanalized arteries after thrombectomy is a significant concern that may lead to poor outcomes. This study aimed to identify the risk factors and evaluate the prognosis of arterial re-occlusion following successful thrombectomy in patients diagnosed with emergent large-vessel occlusion (ELVO). Methods: We retrospectively analyzed data from 155 consecutive patients with ELVO who underwent mechanical thrombectomy (MT). Patients were classified into two groups according to whether the initial recanalized artery was re-occluded within 7 days after successful thrombectomy: re-occlusion and non-occlusion groups. Multivariate analysis was performed for potentially associated variables with p < 0.20 in the univariate analysis to identify the independent risk factors of re-occlusion. Differences in clinical outcomes were also assessed in these two groups. Results: Re-occlusion occurred in 10.3% of patients (16/155). Multivariate analysis demonstrated that large artery atherosclerosis (odds ratio [OR]: 3.942, 95% confidence interval [CI]: 1.247-12.464; p = 0.020), the number of device passes (OR: 2.509, 95% CI: 1.352-4.654; p = 0.004), and residual thrombus/stenosis (OR: 4.123, 95% CI: 1.267-13.415; p = 0.019) were independently associated with re-occlusion. Patients with re-occlusion had significantly worse NIHSS scores at discharge and lower opportunities for achieving functional independence at 3 months after MT than patients without re-occlusion. Conclusions: Large artery atherosclerosis, a high number of thrombectomy device passes, and residual thrombus/stenosis seemed to promote re-occlusion after successful recanalization. Timely identification and proper treatment strategies to prevent re-occlusion are warranted to improve clinical outcomes, especially among high-risk patients.

Early stopping versus continued retrievals after failed recanalization: associated factors and implications for outcome

BACKGROUND

Successful recanalization defined as modified Thrombolysis in Cerebral Infarction Score (mTICI) ≥2b is not achieved in 15%-20% of patients with acute ischemic stroke. This study aims to identify patient-specific factors associated with early stopping without successful recanalization. We hypothesized that the probability of the decision for early stopping during mechanical thrombectomy (MT) is higher in patients with an unfavorable prognosis.

METHODS

All patients enrolled in the German Stroke Registry (GSR) between June 2015 and December 2021 were screened. Inclusion criteria were stroke in the anterior circulation and availability of relevant clinical data. For each retrieval attempt 1-3, patients with stopping and failed reperfusion (mTICI <2b) were compared with all patients with continued retrieval attempts using descriptive statistics and multivariable logistic regression.

RESULTS

Our study included 2977 patients, 350 (12%) of which had early stopping. Higher pre-stroke Modified Rankin Scale (mRS) score (adjusted odds ratio (aOR) =1.20 (95% confidence interval (CI): 1.09; 1.32), P<0.001), higher age (aOR=1.01 (1.00; 1.02), P=0.017) and distal occlusions (aOR=1.93 (1.50; 2.47), P<0.001) as well as intraprocedural dissections/perforations (aOR=4.61 (2.95; 7.20), P<0.001) and extravasation (aOR=2.43 (1.55;3.82), P<0.001) were associated with early stopping. In patients with unsuccessful recanalization (n=622), the number of retrieval attempts (aOR=1.05 (0.94; 1.18), p=0.405) was not associated with unfavorable outcomes (90d-mRS>3).

CONCLUSION

The probability of early stopping was higher in patients with clinical conditions associated with: a) Favorable prognosis and assumed lower impact of recanalization success on functional status, such as distal occlusions; and b) Unfavorable prognosis, such as higher age and reduced pre-stroke functional status. Adverse events during the procedure increased the probability of early stopping. The number of recanalization attempts did not increase the risk of unfavorable outcome for patients with persistent occlusion, supporting the decision for continuation of retrieval attempts.

Association between thrombus composition and first-pass recanalization after thrombectomy in acute ischemic stroke

BACKGROUND

Achieving first-pass recanalization (FPR) has become the primary procedural objective during thrombectomy in acute ischemic stroke patients as it correlates with the best clinical outcome. Understanding factors contributing to FPR failures is essential to enhance FPR success rates. As the central target of thrombectomy, the thrombus itself may be a significant factor influencing FPR.

OBJECTIVES

This study aimed to investigate the association between thrombus composition and FPR success rates.

METHODS

In total, thrombi from 267 ischemic stroke patients were collected in the AZ Groeninge Hospital (Kortrijk, Belgium). Thrombus composition was determined via detailed histologic analysis of red blood cells (RBCs), fibrin, von Willebrand factor, platelets, leukocytes, citrullinated histone 3 (marker for neutrophil extracellular traps), and intracellular and extracellular DNA. FPR was defined as obtaining a modified thrombolysis in cerebral infarction (mTICI) score of 2c/3 after the first pass.

RESULTS

An mTICI score of 2c/3 was obtained in 180 patients, which was achieved via a successful FPR procedure in 126 cases or after multiple passes in 54 cases. Interestingly, thrombi from FPR cases had a different composition from thrombi that needed multiple passes to obtain an mTICI score of 2c/3. FPR thrombi contained significantly more RBCs (P = .0264), less fibrin (P = .0196), and less extracellular DNA (P = .0457).

CONCLUSION

Our results indicate that thrombi characterized by lower RBC content, higher fibrin levels, and increased extracellular DNA are less likely to result in an FPR. These results are important to guide future research aiming at improving procedures or technologies to obtain FPR rates in RBC-poor thrombi.

Endovascular thrombectomy first-pass reperfusion and ancillary device placement

BACKGROUND

Recent randomized trials have demonstrated the efficacy of mechanical thrombectomy in treating acute ischemic stroke, however, further research is required to optimize this technique. We aimed to evaluate the impact of guide catheter position and clot crossing on revascularization rates using A Direct Aspiration First Pass Technique (ADAPT).

METHODS

Data were collected between January 2018 and August 2019 as part of the Spanish ADAPT Registry on ACE catheters (SARA), a multicenter observational study assessing real-world thrombectomy outcomes. Demographic, clinical, and angiographic data were collected. Subgroup analyses assessed the relationship between guide catheter/microguidewire position and modified Trombolysis in Cerebral Infarction (mTICI) scores. First pass effect (FPE) was defined as mTICI 3 after single pass of the device.

RESULTS

From a total of 589 patients, 80.8% underwent frontline aspiration thrombectomy. The median score on the National Institutes of Health Stroke Scale (NIHSS) was 16.0. After adjusting for confounders, the likelihood of achieving FPE (adjusted Odds Ratio (aOR), 0.587; 95% confidence interval (CI), 0.38 to 0.92; p=0.0194) were higher among patients with more distal petrocavernous placement of guide catheter. The likelihood of achieving FPE (aOR, 0.592; 95% CI, 0.39 to 0.90; p=0.0138) and final angiogram complete reperfusion (aOR, 0.465; 95% CI, 0.30 to 0.73; p=0.0008) were higher among patients without microguidewire crossing the clot. No difference was noted for time from arterial puncture to reperfusion in any study group. At the 90-day follow-up, the mortality rate was 9.2% and 65.8% of patients across the entire study cohort were functionally independent (modified Rankin Scale (mRS) 0-2).

CONCLUSIONS

Petrocavernous guide catheter placement improved first-pass revascularization. Crossing the occlusion with a microguidewire lowered the likelihood of achieving FPE and complete reperfusion after final angiogram.

Acute Ischemic Stroke Thrombus Composition

Ischemic stroke is caused by a thrombus blocking one or multiple arteries in the brain, resulting in irreversible damage in the associated brain tissue. The aim of therapy is to restore the blood flow as fast as possible. Two recanalization strategies are currently available: pharmacological thrombolysis using recombinant tissue plasminogen activator (rt-PA) and mechanical removal of the thrombus. Despite recent advancements, achieving efficient recanalization remains a challenge. The precise causes of therapy failure are not fully understood but thrombus composition is likely a key factor in successful recanalization. This review explores acute ischemic stroke thrombus composition, its recently identified components, and how it affects stroke treatment. It also discusses how new insights could enhance current recanalization strategies for ischemic stroke patients.

The effect of actuation frequency on clot integration with the Tigertriever device: A preliminary in vitro study

BACKGROUND

The Tigertriever stent retriever (Rapid Medical) can be actively expanded and contracted by the operator, which allows for several actuation-related parameters to be optimized to potentially improve device efficacy. These parameters have not yet been evaluated. We conducted a benchtop study to evaluate the effect of actuation frequency on clot integration within the stent.

METHODS

A Tigertriever 17 device was deployed within a biological clot analog placed in a straight tube. The device was actuated between the maximally contracted and maximally expanded states with three different frequencies: passive (one-time opening, n = 6), slow (20 s/cycle, n = 6), and fast (5 s/cycle, n = 7). A flat-detector CT scan was acquired, the clot and stent wires were segmented, and the boundaries of the clot and stent wires were calculated on each axial slice. The intersection between the stent and clot boundaries throughout the volume was defined as the volume of clot integrated within the stent. The clot integration factor (ratio of integrated clot volume to total clot volume) was then statistically compared between the three frequencies as an estimate of clot capture efficiency.

RESULTS

The clot integration factor was significantly higher (23% increase, p = 0.01) with the fast actuation as compared to the passive and slow actuations, with a post hoc test showing no difference (p > 0.05) between the passive and slow groups.

CONCLUSIONS

Faster actuation frequencies may result in improved clot integration with the Tigertriever device. This effect needs to be validated by clinical data.

Prospective evaluation to characterize the real-world performance of the EMBOVAC aspiration catheter for neurothrombectomy: a post-market clinical follow-up trial

BACKGROUND

A direct aspiration first pass technique (ADAPT) is an effective alternative to stent retriever thrombectomy for patients with large vessel occlusion (LVO). The PERFECT study evaluated direct aspiration with the EMBOVAC large bore aspiration catheter in patients with LVO strokes.

METHODS

PERFECT was a prospective, post-market, single-arm, multicenter, observational study of patients enrolled across 11 European centers between October 2020 and July 2022. Three direct aspiration passes with EMBOVAC were mandated before switching strategy. The primary endpoint was core-lab assessed successful reperfusion (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2b) post-procedure. Other outcomes included first pass mTICI ≥2c, independent 90-day modified Rankin Scale (mRS) evaluation, and symptomatic intracerebral hemorrhage (sICH) at 24 hours by a clinical events committee.

RESULTS

EMBOVAC was used in 100 patients (mean age 70.4±14.0 years, 59.0% (59/100) female). Final mTICI ≥2b was achieved in 98.0% (97/99), final mTICI ≥2b with no change in frontline therapy or thrombolytics use during the procedure was achieved in 87.9% (87/99), final mTICI ≥2c in 86.9% (86/99), and first pass mTICI ≥2c in 53.5% (53/99). sICH at 24 hours was 0%. The 90-day mRS ≤2 rate was 56.6% (56/99) and all-cause mortality was 12.9%. One device-related serious adverse event occurred within 90 days (1.0%).

CONCLUSIONS

PERFECT demonstrates that EMBOVAC achieves successful reperfusion rates and favorable clinical outcomes when used in the endovascular treatment of acute ischemic stroke (AIS) using a direct aspiration technique as first line therapy in a real-world setting in patients with AIS secondary to large vessel occlusion.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov Unique identifier: NCT04531904.

Flow reversal during stroke thrombectomy

When performing mechanical thrombectomy for stroke patients, some physicians use balloon guide catheters (BGCs) in order to achieve flow reversal and thereby improve reperfusion quality. There is substantial evidence favoring the use of BGCs to improve reperfusion rates and clinical outcomes for thrombectomy patients; however, as we will outline in this review, there is also evidence that BGCs do not achieve reliable flow reversal in many circumstances. Therefore, if we are able to modify our techniques to improve the likelihood of flow reversal during thrombectomy maneuvers, we may be able to further improve reperfusion quality and clinical outcomes. This paper provides an overview of concepts on this topic and outlines some potential techniques to facilitate flow reversal more consistently, including a method to visually confirm it, with the aim of making iterative improvements towards optimal reperfusion for stroke patients.

Economic impact of the first pass effect in mechanical thrombectomy for acute ischaemic stroke treatment in Spain: a cost-effectiveness analysis from the national health system perspective

OBJECTIVE

The mechanical thrombectomy (MT) benefit is related to the degree of reperfusion achieved. First pass effect (FPE) is defined as complete/near revascularisation of the large-vessel occlusion (modified Thrombolysis in Cerebral Infarction (mTICI) 2c-3) after a single device pass. This study assessed the health benefit and economic impact of achieving FPE for acute ischaemic stroke (AIS) patients from the Spanish National Health System (NHS) perspective.

DESIGN

A lifetime Markov model was used to estimate incremental costs and health outcomes (measured in quality-adjusted life-years (QALYs)) of patients that achieve FPE. A subanalysis of the Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischaemic Stroke (STRATIS) registry was performed to obtain clinical outcomes. The base case included all patients that achieved at least a final mTICI ≥2 b, while the alternative scenario included all patients regardless of their final mTICI (0-3). Treatment costs were updated to reflect current practice based on expert panel consensus, while other acute and long-term costs were obtained from a previous cost-effectiveness analysis of MT performed in Spain. Sensitivity analyses were performed to assess the model's robustness.

SETTING

Spanish healthcare perspective.

PARTICIPANTS

AIS patients in Spain.

INTERVENTIONS

FPE following MT.

OUTCOME MEASURES

The model estimated QALYs, lifetime costs and net monetary benefit for the FPE and non-FPE group, depending on the inclusion of reperfusion groups and formal care costs.

RESULTS

STRATIS subanalysis estimated significantly better clinical outcomes at 90 days for the FPE group in all scenarios. In the base case, the model estimated lifetime cost saving per patient of €16 583 and an incremental QALY gain of 1.2 years of perfect health for the FPE group. Cost savings and QALY gains were greater in the alternative scenario (-€44 289; 1.75). In all scenarios, cost savings were driven by the long-term cost reduction.

CONCLUSION

Achieving FPE after MT can lead to better health outcomes per AIS patient and important cost savings for the Spanish NHS.

Diverse thrombus composition in thrombectomy stroke patients with longer time to recanalization

BACKGROUND AND PURPOSE

Delayed time to recanalization is associated with reduced recanalization success of mechanical thrombectomy (MT) and thrombolysis in acute ischemic stroke (AIS). The reasons for this are unclear. We hypothesized that alterations in thrombus structure and composition could be responsible for this.

METHODS

Retrieved thrombi from AIS patients who underwent MT less than 8 h from symptom onset to groin puncture (SOGP) were evaluated. Patients were divided into early (≤4 h.) vs delayed (> 4 h) groups based SOGP timing. Thrombi were histologically analysed using Martius Scarlett Blue and immunohistochemistry staining for von Willebrand Factor (vWF), anti-citrullinated H3 (H3Cit; NETs [neutrophil extracellular traps] marker). We used inferential statistics including, t-test, artificial neural network (ANN) to interpret the data.

RESULTS

A total of 137 thrombi were collected. The overall average percentage of red blood cells (RBC), white blood cells (WBC), platelet, fibrin, H3Cit, and vWF components in thrombi was 45.83%, 3.58%, 22.23%, 28.27%, 19.97% and 16.23% respectively. Delayed group had higher WBCs, (p = 0.02), fibrin (p = 0.02), H3Cit (p = 0.04) and vWF (p = 0.03) thrombus fractions compared to early group. Based on ANN model, the most important factors for predicting the number of passes required for successful recanalization are fibrin and RBC contents of the thrombus followed by vWF and H3Cit contents.

CONCLUSIONS

Longer time to recanalization was associated with increased WBCs, fibrin, H3Cit and vWF fractions of thrombi reflecting possible in situ maturation of thrombus components. Increased fibrin, NETs and vWF composition may reduce likelihood of revascularization by altering thrombus mechanical properties.