Mechanical thrombectomy of distal cerebral vessel occlusions of the anterior circulation.

Mechanical thrombectomy (MT) is frequently performed for distal medium vessel occlusions (DMVO) of the anterior circulation in acute stroke patients. However, evidence for its clinical benefit remains scarce. In this study, we aim to investigate clinical course and safety outcomes of MT in comparison to standard medical therapy (SMT) in DMVO. This single-center retrospective observational study included 138 consecutive patients treated for DMVO of the anterior circulation between 2015 and 2021. To reduce the risk of selection bias, propensity score matching (PSM) of patients with MT versus SMT was performed for the covariates NIHSS and mRS at admission. Out of all 138 patients, 48 (34.8%) received MT and 90 (65.2%) received SMT only. Overall, patients treated with MT showed significantly higher NIHSS and mRS scores at admission. Post 1:1 PSM, there was a trend toward a better NIHSS improvement in patients with MT (median 4 vs. 1, P = 0.1). No significant differences were observed in the occurrence of symptomatic intracranial hemorrhage or mortality between the groups before and after PSM. A subgroup analysis showed significantly higher NIHSS improvement (median 5 versus 1, P = 0.01) for patients with successful MT (≥ mTICI 2b). Mechanical thrombectomy for distal medium vessel occlusions (DMVO) in the anterior circulation appeared safe and feasible. Successful recanalization was associated with clinical improvement. Larger, multi-center, randomized-controlled trials are required to corroborate these findings.

Endovascular thrombectomy for basilar artery occlusion stroke: Analysis of the German Stroke Registry-Endovascular Treatment.

BACKGROUND AND PURPOSE: Acute ischemic stroke due to basilar artery occlusion (BAO) causes the most severe strokes and has a poor prognosis. Data regarding efficacy of endovascular thrombectomy in BAO are sparse. Therefore, in this study, we performed an analysis of the therapy of patients with BAO in routine clinical practice. METHODS: Patients enrolled between June 2015 and December 2019 in the German Stroke Registry-Endovascular Treatment (GSR-ET) were analyzed. Primary outcomes were successful reperfusion (modified Thrombolysis in Cerebral Infarction [mTICI] score of 2b-3), substantial neurological improvement (≥8-point National Institute of Health Stroke Scale [NIHSS] score reduction from admission to discharge or NIHSS score at discharge ≤1), and good functional outcome at 3 months (modified Rankin Scale [mRS] score of 0-2). RESULTS: Out of 6635 GSR-ET patients, 640 (9.6%) patients (age 72.2 ± 13.3, 43.3% female) experienced BAO (median [interquartile range] NIHSS score 17 [8, 27]). Successful reperfusion was achieved in 88.4%. Substantial neurological improvement at discharge was reached by 45.5%. At 3-month follow-up, good clinical outcome was observed in 31.1% of patients and the mortality rate was 39.2%. Analysis of mTICI3 versus mTICI2b groups showed considerable better outcome in those with mTICI3 (38.9% vs. 24.4%; p = 0.005). The strongest predictors of good functional outcome were intravenous thrombolysis (IVT) treatment (odds ratio [OR] 3.04, 95% confidence interval [CI] 1.76-5.23) and successful reperfusion (OR 4.92, 95% CI 1.15-21.11), while the effect of time between symptom onset and reperfusion seemed to be small. CONCLUSIONS: Acute reperfusion strategies in BAO are common in daily practice and can achieve good rates of successful reperfusion, neurological improvement and good functional outcome. Our data suggest that, in addition to IVT treatment, successful and, in particular, complete reperfusion (mTICI3) strongly predicts good outcome, while time from symptom onset seemed to have a lower impact.

Breaking with a dogma: persisting diffusion restrictions (pDWI) in follow-up after endovascular treatment for stroke.

BACKGROUND: Post-stroke diffusion weighted imaging (DWI) signal transformation of the infarct core, which results in high apparent diffusion coefficient (ADC) values and variable DWI signal intensity, is completed no later than 1 month after onset of ischemia. We observed frequent exceptions to this timeline of change in DWI signal, which led to uncertainties in further clinical patient management. METHODS: A prospective single-center study of patients treated with mechanical thrombectomy of a large vessel occlusion in the anterior circulation was conducted. Patients received high-resolution MRI at 3T, including DWI, in the acute post-stroke phase and in the follow-up after 3-12 months. RESULTS: Overall, 78 patients (45 men) of mean age 63.6 years were evaluated. We identified persisting or new diffusion restriction in 29 of the 78 patients (37.2%) on follow-up imaging. Diffusion restrictions in a different location from the infarct core, representing new (sub-)acute ischemia, were observed in four patients (5.1%). Smaller areas of persisting diffusion restriction (pDWI lesions with high DWI signal and reduced ADC values) within the former infarct core were observed in 25 patients (32.1%) without clinical evidence of recurrent stroke, but with worse outcome scores at follow-up compared with patients without pDWI lesions. The presence of pDWI lesions is associated with a large primary infarct core (multivariate regression OR 1.03 (95% CI 1.01 to 1.05); p<0.01), mediating the relationship between pDWI lesions and clinical outcome. CONCLUSION: Smaller foci of persisting diffusion restriction (pDWI lesions) in the follow-up after endovascular treatment for stroke are frequent and likely represent a slowed ADC signal progression within a formerly large infarct core.

Impact of aspiration catheter size on first-pass effect in the combined use of contact aspiration and stent retriever technique.

BACKGROUND AND PURPOSE: The first-pass effect (FPE), defined as a first-pass Expanded Treatment in Cerebral Ischaemia (eTICI) 2c/3 reperfusion, has emerged as a key metric of efficacy in mechanical thrombectomy (MT) for acute ischaemic stroke. The proximal balloon occlusion together with direct thrombus aspiration during stent retriever thrombectomy (PROTECT)-PLUS technique consists in the use of a balloon guide catheter and a combined MT approach involving contact aspiration and a stent retriever. The aim of this study is to assess the effectiveness and safety of the PROTECT-PLUS technique using distal aspiration catheters (DACs) with different inner diameters by comparing the large-bore DAC Catalyst 7 versus the use of medium-bore DACs. METHODS: Retrospective analysis of a prospectively maintained database of patients treated with PROTECT-PLUS using Catalyst 7, Catalyst 6 or Catalyst 5 with an occlusion of either the terminal carotid artery or the M1 or M2 segments of the middle cerebral artery from 2018 to 2020 in two comprehensive stroke centres. Baseline characteristics and procedural, safety and clinical outcomes were compared between groups. Multivariable logistic regression analysis was performed in order to find independent predictors of FPE. RESULTS: We identified 238 consecutive patients treated with PROTECT-PLUS as front-line approach using Catalyst 7 (n=86), Catalyst 6 (n=78) and Catalyst 5 (n=76). The rate of FPE was higher with Catalyst 7 (54%) than Catalyst 6 (33%, p=0.009) and Catalyst 5 (32%, p=0.005), in addition to higher final eTICI 2c/3 reperfusion rates, shorter procedural times, lower need of rescue therapy and fewer procedure-related complications. After multivariable analysis the sole independent factor associated to FPE was the use of Catalyst 7 (OR 2.34; 95% CI 1.19 to 4.58; p=0.014). CONCLUSION: Further development of combined MT by incorporating larger-bore aspiration catheters is associated with higher reperfusion rates, shorter procedure times, and lower need of rescue therapy while reducing the complication rates.

Further Development of Combined Techniques Using Stent Retrievers, Aspiration Catheters and BGC : The PROTECTPLUS Technique.

PURPOSE: First pass complete (mTICI 3) reperfusion must be regarded as the ultimate goal in mechanical thrombectomy (MT) in patients suffering from an emergent large vessel occlusion (ELVO). With this in mind a technical modification of the previously published PROTECT (PRoximal balloon Occlusion TogEther with direCt Thrombus aspiration during stent retriever thrombectomy) approach, the PROTECTPLUS technique was evaluated. Under proximal flow arrest using a balloon guide catheter (BGC), a stent retriever was only partially inserted into a large-bore aspiration catheter. This construction was subsequently retracted as a unit into the BGC with aspiration both at the aspiration catheter and at the BGC. METHODS: A case-control study was performed comparing the PROTECT technique with the PROTECTPLUS technique with respect to the technical and procedural parameters. Patients n = 165 (101 PROTECT, 64 PROTECTPLUS) with ELVO of either the terminus of the internal carotid artery or the proximal middle cerebral artery were included. RESULTS: Using the PROTECTPLUS resulted in a higher rate of first pass complete reperfusions (59.4% vs. 27.7%, p < 0.001) as compared with PROTECT. The PROTECTPLUS also led to shorter procedure times (21 min vs. 37 min, p = 0.001) and higher rates of overall complete reperfusion (73.5% vs. 49.5%, p = 0.014) compared to PROTECT. CONCLUSION: The PROTECTPLUS technique is a promising technical modification to further optimize endovascular stroke treatment.

PROTECT: PRoximal balloon Occlusion TogEther with direCt Thrombus aspiration during stent retriever thrombectomy - evaluation of a double embolic protection approach in endovascular stroke treatment.

PURPOSE: Stent retriever-based mechanical thrombectomy (MT) for emergent large vessel occlusions (ELVO) is often complicated by thrombus fragmentation causing distal embolization and embolization to new vascular territories. Well-established embolic protection approaches include proximal flow arrest and distal aspiration techniques during stent retriever maneuvers. Aiming at the reduction of thrombus fragmentation during MT we evaluated a technical approach combining proximal balloon occlusion together with direct thrombus aspiration during MT: the PROTECT technique. METHODS: We performed a case-control study comparing the PROTECT technique with sole distal aspiration during MT regarding technical and procedural parameters, n=200 patients with ELVO of either the terminus of the internal carotid artery or the proximal middle artery were included. RESULTS: PROTECT resulted in a shorter procedure time (29 vs 40 min; P=0.002), in a higher rate of successful recanalizations (100% vs 78%; P=0.001) and a higher rate of complete reperfusions (70% vs 39%; P<0.001) compared with sole distal aspiration during MT. CONCLUSION: The PROTECT technique is a promising new approach to significantly reduce thrombus fragmentation and, hence distal embolization during MT. This safe and efficient technique needs to be validated in larger trials to confirm our results.