Posterior Circulation Occlusions May Be Associated with Distal Emboli During Thrombectomy : Factors for Distal Embolization and a Review of the Literature

Reevaluating the role of heparin during mechanical thrombectomy for acute ischemic stroke: Increased risks without functional benefit

BACKGROUND

Heparin may be administered during mechanical thrombectomy (MT) for acute ischemic stroke due to large vessel occlusions (AIS-LVO), with the aim of enhancing reperfusion and improving patient outcomes. The uncertain balance between risks and benefits of administering heparin during MT prompted us to perform this systematic review and meta-analysis.

METHODS

A comprehensive search was conducted in PubMed, Embase, and Scopus to find studies that report the safety or efficacy of administering heparin during MT for AIS-LVO. Meta-analysis was performed using the random effects model. In case of significant heterogeneity a subgroup analysis was performed.

RESULTS

From 2398 screened records, we included 15 studies. Rate of favorable functional outcome (90 day modified Rankin Scale 0-2 (mRS 0-2)) was lower among patients who received heparin (OR, 0.88 [95 %CI 0.79-0.98]; p=.023). Risk of distal embolization was higher in patients who received heparin (OR, 1.25 [95 %CI 1.01-1.55]; p=.04). The subgroup analysis showed that patients who received intravenous thrombolysis (IVT) had higher risk of Symptomatic intracranial hemorrhage (sICH) (OR, 2.94 [95 %CI 1.30-6.63]; p=.009) and lower rate of mRS 0-2 (OR, 0.66 [95 %CI 0.50-0.87]; p=.004). Heparin use didn't affect successful reperfusion rate (Thrombolysis in cerebral infarction ≥2B), mortality or any ICH risk.

CONCLUSION

Overall, our analysis indicates that administering heparin during MT for AIS-LVO correlates with worse clinical outcomes and increased distal embolization rates. Moreover, it is linked to a higher risk of sICH in patients who receive IVT. Consequently, the routine utilization of heparin during MT should be reconsidered.

Predictors of distal embolization during thrombectomy for anterior circulation large vessel bifurcation occlusion stroke

BACKGROUND

Distal embolization is a frequent complication of mechanical thrombectomy (MT) for acute ischemic stroke, often leading to poor clinical outcomes. The vascular bifurcations represent a specialized anatomical location, thereby augmenting the complexity of MT. The specific factors contributing to distal embolization in this context have not been thoroughly explored. This study seeks to identify the factors associated with distal embolization during MT in patients with anterior circulation large vessel bifurcation occlusion stroke.

METHODS

A retrospective analysis was conducted on patients who underwent MT for acute anterior circulation bifurcation occlusion stroke between January 2015 and December 2023. Baseline characteristics, procedural details, and clinical outcomes were assessed. Univariate and multivariable analyses were performed to identify predictors of distal embolization during MT.

RESULTS

The study included 119 patients. Univariate analysis revealed significant associations between distal embolization and occlusion location, internal carotid artery (ICA) tortuosity, first-line thrombectomy strategy, and the number of device passes. Multivariate analysis identified ICA bifurcation occlusions (odds ratio (OR) 3.21, 95% confidence interval (CI) 1.188 to 8.672, P=0.021), stent retriever thrombectomy (SRT) (OR 6.177, 95% CI 1.77 to 21.555, P=0.004), and a higher number of device passes (OR 1.778, 95% CI 1.132 to 2.792, P=0.013) as independent predictors of distal embolization.

CONCLUSIONS

ICA bifurcation occlusion, the use of SRT, and an increased number of device passes are significant predictors of distal embolization during MT in patients with anterior circulation large vessel bifurcation occlusion strokes.

Endovascular therapy of acute vertebrobasilar occlusions: influence of first-line strategy in the Endovascular Treatment in Ischemic Stroke (ETIS) Registry

BACKGROUND

The choice of the first-line technique in vertebrobasilar occlusions (VBOs) remains challenging. We aimed to report outcomes in a large cohort of patients and to compare the efficacy and safety of contact aspiration (CA) and combined technique (CoT) as a first-line endovascular technique in patients with acute VBOs.

METHODS

We retrospectively analyzed clinical and neuroradiological data of patients with VBOs from the prospective, multicenter, observational Endovascular Treatment in Ischemic Stroke (ETIS) Registry in France between January 2015 and August 2023. The primary outcome was the first pass effect (FPE) rate, whereas modified Thrombolysis In Cerebral Infarction (mTICI) 2b-3 and 2c-3, number of passes, need for rescue strategy, modified Rankin Scale (mRS) 0-2, mortality, and symptomatic intracranial hemorrhage (sICH) were secondary outcomes. We performed univariate and multivariate analyses to investigate differences between the two groups.

RESULTS

Among the 583 included patients (mean age 66.2 years, median National Institutes of Health Stroke Scale (NIHSS) 13, median posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) 8), 393 were treated with CA alone and 190 with CoT. Procedures performed with CA were shorter compared with CoT (28 vs 47 min, P<0.0001); however, no differences were observed in terms of FPE (CA 43.3% vs CoT 38.4%, P=0.99), and successful final recanalization (mTICI 2b-3, CA 92.4% vs CoT 91.8%, P=0.74) did not differ between the two groups. Functional independence and sICH rates were also similar, whereas mortality was significantly lower in the CA group (34.5% vs 42.9%; OR 1.79, 95% CI 1.03 to 3.11).

CONCLUSIONS

We observed no differences in FPE, mTICI 2b-3, sICH, and functional independence between the two study groups. First-line CA was associated with shorter procedures and lower mortality rates than CoT.

Pre-navigation balloon technique: Distal emboli protection during stent retriever thrombectomy

OBJECTIVE

During stent retriever thrombectomy, a balloon guide catheter reduces distal emboli and consequently improves clinical outcomes. Because balloons are usually used before stent retrieval, these can affect the thrombus including the distal emboli while performing microcatheter navigation. This study aimed to evaluate the usefulness and safety of the pre-navigation balloon technique during microcatheter and microwire navigation.

METHODS

Patients who underwent stent retriever thrombectomy secondary to an anterior circulation large-artery occlusion were retrospectively evaluated. The pre-navigation balloon technique was used, and the number of retrievals, procedure time, final recanalization, presence of distal emboli, first-pass effect (FPE), symptomatic intracranial hemorrhage including procedure-related complications, and clinical outcomes at 3 months were evaluated.

RESULTS

In total 123 patients were analyzed, and occurrence of distal emboli was lesser in the pre-navigation balloon than in the non-preballoon group (4.4% vs. 11.5%, p = 0.02). No statistical difference was found in successful recanalization, mortality, and procedure-related complications. Moreover, the pre-navigation balloon group had a higher FPE than the non-balloon group (37.8% vs. 20.5%, p = 0.004). Although no statistical difference was found in the pre-navigation balloon group, a trend toward a higher rate of good clinical outcomes was observed (mRS 0-2 at 3 months, 55.6% vs. 48.7%, p = 0.09). For ICA occlusion(n = 35), significant effects were seen in decreasing distal embolism (0(0%) vs 3(16%), p = 0.01), increasing FPE (8(50%) vs 6(32%), p = 0.003), and improving clinical outcomes (mRS 0-2 at 3 months, 9(56%) vs 7(37%), p = 0.03) in the pre-navigation balloon group. In the multivariate analysis, lesser distal embolism (0.91 [0.80-1.00], p = 0.02), higher successful recanalization (3.52 [1.11-7.03], p = 0.016), and higher FPE (3.17 [1.83-7.37], p = 0.001) secondary to the procedure was a predictor of favorable clinical outcomes.

CONCLUSIONS

The pre-navigation balloon technique significantly reduced occurrence of distal embolism and increased the FPE.

Predictors of Emboli in Mechanical Thrombectomy for Anterior Circulation Stroke

OBJECTIVE

Emboli commonly occurs in mechanical thrombectomy (MT). The objective of this study was to analyze predicting factors of emboli after MT.

METHODS

Patients who underwent MT with successful reperfusion for anterior circulation occlusion were enrolled. Emboli included distal emboli at digital subtraction angiography (DSA) and unexpected embolic infarct on diffusion-weighted image (DWI) without distal emboli at DSA. Baseline characteristics, procedural details, angiographic outcomes, and clinical outcomes were reviewed. Multivariable analyses were performed to evaluate predictive factors for the occurrence of emboli.

RESULTS

Of 601 patients, 149 (24.8%) patients had distal emboli at DSA, and 169 (28.1%) patients had unexpected embolic infarction on DWI even without distal emboli at DSA. A total of 318 (52.9%) patients were enrolled in the embolic group, and 283 (47.1%) patients were assigned to the non-embolic group. In multivariate analysis, larger microcatheter (OR 1.26, 95% CI 1.12-1.94; p = 0.047), clot passage (OR 1.33, 95% CI 1.07-1.87; p = 0.041), use of balloon guide catheter (BGC) (OR 0.70, 95% CI 0.52-0.92; p = 0.014), early ballooning of BGC (OR 0.68, 95% CI 0.50-0.90; p = 0.009), and longer stent retriever (OR 0.72, 95% CI 0.54-0.90; p = 0.029) were associated with occurrence of emboli.

CONCLUSION

MT with only a stent retriever, use of a larger microcatheter, and clot passage might increase the risk of emboli. In contrast, contact aspiration thrombectomy, use of BGC, early ballooning of BGC, and use of longer stent retrievers could reduce the chance of emboli.

Short-term efficacy of stenting as a rescue therapy for acute atherosclerotic occlusion in anterior cerebral circulation

Purpose

The study aimed to explore the efficacy and safety of the Neuroform EZ stent in treating acute anterior circulation large artery occlusion.

Methods

The clinical data of 42 consecutive patients with acute anterior circulation large atherosclerotic occlusion who were treated with the Neuroform EZ stent from January 2018 to August 2019 in our stroke care center, including baseline characteristics, images, therapeutic condition, and follow-up data were retrospectively analyzed.

Results

There were 42 mechanical thrombectomy (MT) failure cases of intracranial atherosclerotic stenosis with rescue Neuroform EZ stent implantation, of which 78.6% (33/42) had a good prognosis and 88.1% (37/42) showed no re-stenosis at follow-up. The average time from puncture to recanalization is 79.50 ± 14.19 min. The successful rate of intraoperative stent release is 97.6%, while there is one case of stent displacement, three cases of thrombus escape, and six cases of hemorrhage.

Conclusion

Rescue therapy of the Neuroform EZ stent for acute anterior circulation large atherosclerotic occlusion can archive good short-term imaging and clinical results, while long-term follow-up is still needed to verify.

Bridging thrombolysis improves survival rates at 90 days compared with direct mechanical thrombectomy alone in acute ischemic stroke due to basilar artery occlusion: a systematic review and meta-analysis of 1096 patients

BACKGROUND

Mechanical thrombectomy (MT) is an effective treatment for patients with acute ischemic stroke (AIS) from basilar artery occlusion (BAO).

OBJECTIVE

To compare the clinical outcomes of MT, with and without bridging intravenous thrombolysis (IVT), in acute BAO through a systematic review and meta-analysis of the current literature.

METHODS

Systematic searches of Medline, EMBASE, and Cochrane Central were undertaken on August 1, 2022. Good functional outcome defined as 90-day modified Rankin Scale score 0-2 was the primary outcome measure. Secondary outcome measures were 90-day mortality, successful post-thrombectomy recanalization (modified Thrombolysis in Cerebral Infarction score ≥2b), symptomatic intracranial hemorrhage (sICH), and subarachnoid hemorrhage (SAH).

RESULTS

Three studies reporting 1096 patients with BAO AIS were included in the meta-analysis. No significant differences in good functional outcome were detected between the two groups (RR=1.28 (95% CI 0.86 to 1.92); p=0.117). However, specifically patients with large artery atherosclerosis (LAA) benefited from bridging IVT (OR=2.52 (95% CI 1.51 to 4.22); p<0.001) with better functional outcomes. There was a significantly lower 90-day mortality rate for patients who underwent bridging IVT compared with MT alone (RR=0.70 (95% CI 0.62 to 0.80); p=0.008). No significant differences were detected in rates of post-treatment recanalization (RR=1.01 (95% CI 0.35 to 2.91); p=0.954), sICH (RR=0.96 (95% CI 0.66 to 1.42); p=0.724), and SAH (RR=0.93 (95% CI 0.31 to 2.83); p=0.563).

CONCLUSIONS

In patients with AIS due to BAO, bridging IVT was associated with lower mortality rates at 90 days, compared with direct MT. There were no improved functional outcomes or increased sICH or SAH between both arms, However, patients with LAA benefited from bridging IVT, with better functional outcomes.

Feasibility and safety of ADAPT in acute distal posterior cerebral artery occlusions

PURPOSE

The direct aspiration first pass technique (ADAPT) is an effective and safe endovascular treatment for distal medium vessel occlusions (DMVO) of the anterior circulation. Clinical experience with ADAPT in the distal posterior circulation, however, is still limited and published data is scarce. In this original work, feasibility, safety and efficacy of ADAPT with distal access catheters (DAC) for treatment of acute distal posterior cerebral artery occlusions (DPCAOs) is evaluated.

METHOD

All acute ischemic stroke patients between 2017 and 2022 with primary or secondary DPCAOs in the P2 or P3 segment, that underwent thrombectomy of the DPACO using ADAPT with DACs as frontline therapy, were identified. Demographic data, recanalization rates, procedural safety, and clinical outcome were assessed.

RESULTS

Twenty-four patients with primary (n = 6) or secondary (n = 18) DPCAOs (P2: 21/24; P3: 3/24) were included. Median NIHSS score at admission was 14.5 (IQR 9.5). In all cases, the DPCAO could be reached with the DAC. Successful revascularization (DMVO-p-TICI ≥ 2b) with ADAPT was achieved in 79.2% (19/24), including a first pass effect of 62.5% (15/24), leading to complete recanalization (DMVO-p-TICI 3). Median number of passes was 1 (range 1-2). No complications related to distal PCA aspiration thrombectomy occurred. Median NIHSS and mRS scores at discharge were 4 (IQR 8) and 3 (IQR 2), respectively.

CONCLUSIONS

ADAPT appears to be feasible, safe and effective for the treatment of acute DPCAOs in the setting of different occlusion patterns. High revascularization rates without procedural complications can be achieved. Further studies are needed to consolidate these results.

Endovascular treatment for isolated posterior cerebral artery occlusion stroke in the MR CLEAN registry

BACKGROUND

Endovascular treatment (EVT) is standard of care in anterior circulation large vessel occlusions. In posterior circulation occlusions, data on EVT in isolated posterior cerebral artery (PCA) occlusions are limited, although PCA occlusions can cause severe neurological deficit.

OBJECTIVE

To describe in a prospective study the clinical manifestations, outcomes, and safety of EVT in isolated PCA occlusions.

METHODS

We used data (2014-2017) from the MR CLEAN Registry, a nationwide, prospective cohort of EVT-treated patients in the Netherlands. We included patients with acute ischemic stroke (AIS) due to an isolated PCA occlusion on CT angiography. Patients with concurrent occlusion of the basilar artery were excluded. Outcomes included change in National Institutes of Health Stroke Scale (ΔNIHSS) score, modified Rankin Scale (mRS) score 0-3 after 90 days, mortality, expanded Thrombolysis in Cerebral Infarction (eTICI), and periprocedural complications.

RESULTS

Twenty (12%) of 162 patients with posterior circulation occlusions had an isolated PCA occlusion. Median age was 72 years; 13 (65%) were women. Median baseline NIHSS score was 13 (IQR 5-21). Six (30%) patients were comatose. Twelve patients (60%) received IVT. Median ΔNIHSS was -4 (IQR -11-+1). At follow-up, nine patients (45%) had mRS score 0-3. Seven (35%) died. eTICI 2b-3 was achieved in 13 patients (65%). Nine patients (45%) had periprocedural complications. No symptomatic intracranial hemorrhages (sICH) occurred.

CONCLUSIONS

EVT should be considered in selected patients with AIS with an isolated PCA occlusion, presenting with moderate-severe neurological deficits, as EVT was technically feasible in most of our patients and about half had good clinical outcome. In case of lower NIHSS score, a more conservative approach seems warranted, since periprocedural complications are not uncommon. Nonetheless, EVT seems reasonably safe considering the absence of sICH in our study.

Frontline thrombectomy strategy and outcome in acute basilar artery occlusion

BACKGROUND

Novel thrombectomy strategies emanate expeditiously day-by-day counting on access system, clot retriever device, proximity to and integration with the thrombus, and microcatheter disengagement. Nonetheless, the relationship between native thrombectomy strategies and revascularization success remains to be evaluated in basilar artery occlusion (BAO).

PURPOSE

To compare the safety and efficacy profile of key frontline thrombectomy strategies in BAO.

METHODS

Retrospective analyses of prospectively maintained stroke registries at two comprehensive stroke centers were performed between January 2015 and December 2019. Patients with BAO selected after MR imaging were categorized into three groups based on the frontline thrombectomy strategy (contact aspiration (CA), stent retriever (SR), or combined (SR+CA)). Patients who experienced failure of clot retrieval followed by an interchanging strategy were categorized as a fourth (switch) group. Clinicoradiological features and procedural variables were compared. The primary outcome measure was the rate of complete revascularization (modified Thrombolysis in Cerebral Infarction (mTICI) grade 2c-3). Favorable outcome was defined as a 90 day modified Rankin Scale score of 0-2.

RESULTS

Of 1823 patients, we included 128 (33 underwent CA, 35 SR, 35 SR +CA, and 25 switch techniques). Complete revascularization was achieved in 83/140 (59%) primarily analyzed patients. SR +CA was associated with higher odds of complete revascularization (adjusted OR 3.04, 95% CI 1.077 to 8.593, p=0.04) which was an independent predictor of favorable outcome (adjusted OR 2.73. 95% CI 1.152 to 6.458, p=0.02). No significant differences were observed for symptomatic intracranial hemorrhage, functional outcome, or mortality rate.

CONCLUSION

Among BAO patients, the combined technique effectively contributed to complete revascularization that showed a 90 day favorable outcome with an equivalent complication rate after thrombectomy.

Percutaneous transluminal angioplasty and stenting in acute stroke caused by basilar artery steno-occlusive disease: The experience of a single stroke centre

BACKGROUND

Percutaneous transluminal angioplasty and stenting in acute stroke due to severe basilar artery stenosis or basilar artery occlusion remain a matter of debate. The higher risk of stroke recurrence in patients with vertebrobasilar stenosis compared to anterior circulation atherosclerotic disease creates high expectations concerning endovascular approaches. This study aims to review our experience with percutaneous transluminal angioplasty and stenting in acute stroke caused by basilar artery steno-occlusive disease.

METHODS

Our prospective database from June 2014 until December 2020 was screened and patients with acutely symptomatic severe (>80%) basilar artery stenosis or acute basilar artery occlusion who underwent percutaneous transluminal angioplasty and stenting were analysed.

RESULTS

Twenty-five patients included: 72% men (mean age 68.6 years), all with prior modified Rankin Scale <2. Twelve presented with acute basilar artery occlusion and were submitted to mechanical thrombectomy before percutaneous transluminal angioplasty and stenting, while the remaining had severe basilar artery stenosis. Successful stent placement was achieved in 22 (88%). Procedure-related complications included new small ischemic lesions (16%), basilar artery dissection (8%), vertebral artery dissection (12%) and death (12%). At 3 months post-percutaneous transluminal angioplasty and stenting, 10 out of 23 patients (43.5%) were independent (mRS ≤ 2) and six died. Fourteen patients underwent transcranial Doppler ultrasound 3 months post-percutaneous transluminal angioplasty and stenting: 12 showed residual stenosis, one significant stent restenosis and one presented stent occlusion.

CONCLUSIONS

Percutaneous transluminal angioplasty and stenting showed to be a technically feasible and reasonably safe procedure in selected patients. However, good clinical outcomes may be difficult to achieve as only 43.5% of the patients remained independent at 3 months. Randomized studies are needed to confirm the efficacy and safety outcomes of percutaneous transluminal angioplasty and stenting in acute stroke caused by basilar artery steno-occlusive disease.

What You Always Wanted to Know about Endovascular Therapy in Acute Ischemic Stroke but Never Dared to Ask: A Comprehensive Review

In 2015, mechanical thrombectomy (MT) in combination with intravenous thrombolysis was demonstrated to be superior to best medical treatment alone in patients with anterior circulation stroke. This finding resulted in an unprecedented boost in endovascular stroke therapy, and MT became widely available. MT was initially approved for patients presenting with large vessel occlusion in the anterior circulation (intracranial internal carotid artery or proximal middle cerebral artery) within a 6-hour time window. Eventually, it was shown to be beneficial in a broader group of patients, including those without known symptom-onset, wake-up stroke, or patients with posterior circulation stroke. Technical developments and the implementation of novel thrombectomy devices further facilitated endovascular recanalization for acute ischemic stroke. However, some aspects remain controversial. Is MT suitable for medium or very distal vessel occlusions? Should emergency stenting be performed for symptomatic stenosis or recurrent occlusion? How should patients with large vessel occlusion without disabling symptoms be treated? Do certain patients benefit from MT without intravenous thrombolysis? In the era of personalized decision-making, some of these questions require an individualized approach based on comorbidities, imaging criteria, and the severity or duration of symptoms. Despite its successful development in the past decade, endovascular stroke therapy will remain a challenging and fascinating field in the years to come. This review aims to provide an overview of patient selection, and the indications for and execution of MT in patients with acute ischemic stroke.

Comparing the Conventional and Balloon-Guided Catheter-Assisted SWIM Technology for the Treatment of Acute Ischemic Stroke

Objective

Acute ischemic stroke is common in elder patients. This study investigates whether using the balloon-guided catheter (BGC) would improve the effect of stent thrombectomy (Solitaire FR With Intracranial Support Catheter for Mechanical Thrombectomy, SWIM) for patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO).

Method

The data of 209 patients with AIS-LVO underwent SWIM were collected retrospectively from January 2017 to June 2021. These patients were divided into two groups based on whether they used of BGC or not. The propensity score matching (PSM) analysis was used to compare the differences in the first pass effect (FPE), successful recanalization, embolus escape rate, symptomatic intracranial hemorrhage (sICH), 90-day clinical favorable outcome, 90-day all-cause mortality, and complications in the patients treated with SWIM combined with balloon-guided catheter or conventional catheter.

Results

Among the 209 patients, 44 patients were treated with BGC and 165 patients were not. After matching, a total of 111 patients were included. The results showed that there was no statistical difference in FPE (35.1% in non-BGC group compared to 24.3% in BGC group, matched RR, 0.59; 95% CI, 0.24–1.44), successful recanalization (89.2 vs. 91.9%, matched RR, 1.37; 95%CI, 0.34–5.51), embolus escape (6.8 vs. 8.1%, matched RR, 1.22; 95%CI, 0.28–5.40), sICH (8.1 vs. 13.5%; matched RR, 1.77; 95%CI 0.50–6.24), 90-day clinical favorable outcome (48.7 vs. 54.1%, matched RR, 1.11; 95%CI 0.51–2.46), 90-day all-cause mortality (17.6 vs. 21.6%, matched RR, 1.29; 95%CI 0.48–3.47), and the incidence of complications (6.8 vs. 5.4%, matched RR, 0.79 95%CI 0.15–4.27). These results indicate that using SWIM as the first-line treatment for patients with AIS-LVO, there is no statistical significance in FPE, final successful recanalization, distal emboli, sICH, procedural time, 90-day favorable outcome, 90-day mortality, and complications with or without BGC.

Conclusion

Balloon-guided catheter does not affect the result of using SWIM as the first-line treatment for patients with AIS-LVO. Our results will guide daily practice, with the adoption of the use of a guided catheter without a balloon.

Thrombectomy of symptomatic isolated occlusions of posterior cerebral arteries in segment P1 and P2 in acute stroke treatment

BACKGROUND

Interventional stroke treatments for occlusions of the posterior circulation are established procedures. However, there are limited data on the treatment of isolated symptomatic P1 and P2 occlusions, which we have examined in this study.

PURPOSE

To investigate the mechanical thrombectomy of distal posterior occlusions.

MATERIAL AND METHODS

Retrospectively, data from patients with isolated P1 and P2 occlusions treated with MT were evaluated. Successful reperfusions have been defined as modified thrombolysis in cerebral infarct (mTICI) Grade 2b-3. A good clinical outcome was defined as a 90-day modified Rankin score 0-2.

RESULTS

All 79 treated patients were primarily aspirated. Stent retrievers were used secondarily in nine patients. Successful reperfusion was achieved in 95% of patients. Of the patients, 57% had a favorable clinical outcome after 90 days.

CONCLUSION

Mechanical thrombectomy with first line aspiration of symptomatic P1 and P2 occlusions is a safe and effective procedure.

Endovascular Treatment for Posterior Circulation Stroke: Ways to Maximize Therapeutic Efficacy

The efficacy of endovascular treatment (EVT) in patients with posterior circulation stroke has not been proven. Two recent randomized controlled trials failed to show improved functional outcomes after EVT for posterior circulation stroke (PC-EVT). However, promising results for two additional randomized controlled trials have also been presented at a recent conference. Studies have shown that patients undergoing PC-EVT had a higher rate of futile recanalization than those undergoing EVT for anterior circulation stroke. These findings call for further identification of prognostic factors beyond recanalization. The significance of baseline clinical severity, infarct volume, collaterals, time metrics, core-penumbra mismatch, and methods to accurately measure these parameters are discussed. Furthermore, their interplay on EVT outcomes and the potential to individualize patient selection for PC-EVT are reviewed. We also discuss technical considerations for improving the treatment efficacy of PC-EVT.

Endovascular treatment with or without intravenous alteplase for acute ischaemic stroke due to basilar artery occlusion

Background and purpose

It remains controversial if endovascular treatment (EVT) can improve the outcome of patients with acute basilar artery occlusion (BAO). This study aims to compare the functional outcomes between EVT with and without intravenous thrombolysis (IVT) first in patients who had acute ischaemic stroke (AIS) due to BAO.

Methods

Patients who had AIS with BAO who underwent EVT within 24 hours of onset were enrolled in this multicentre cohort study, and the efficacy and safety were compared between IVT+EVT and direct EVT. The primary outcome was 90-day functional independence. All outcomes were assessed with adjusted OR (aOR) from the multivariable logistic regression. In addition, a meta-analysis was performed on all recently published pivotal studies on functional independence after EVT in patients with BAO.

Results

Of 310 enrolled patients with BAO, 241 (78%) were treated with direct EVT and 69 (22%) with IVT+EVT. Direct EVT was associated with a worse functional outcome (aOR, 0.46 (95% CI 0.24 to 0.85), p=0.01). IVT+EVT was associated with a lower percentage of patients who needed ≥3 passes of stent retriever (10.14% vs 20.75%). The meta-analysis regression revealed a potential positive correlation between bridging with IVT first and functional independence (r=0.14 (95% CI 0.05 to 0.24), p<0.01).

Conclusions

This study showed that compared with direct EVT, EVT with IVT first was associated with better functional outcomes in patients with BAO treated within 24 hours of onset. The meta-analysis demonstrated similar favourable efficacy of IVT first followed by EVT in patients with BAO.

Biomarkers of Technical Success After Embolectomy for Acute Stroke

PURPOSE OF THE REVIEW

Stent retrievers and large-bore aspiration catheters have doubled substantial reperfusion rates compared to first-generation devices. This has been accompanied by a 3-fold reduction in procedural time to revascularization. To measure future thrombectomy improvements, new benchmarks for technical efficacy are needed. This review summarizes the recent literature concerning biomarkers of procedural success and harm and highlights future directions.

RECENT FINDINGS

Expanded Treatment in Cerebral Ischemia (eTICI), which incorporates scores for greater levels of reperfusion, improves outcome prediction. Core laboratory-adjudicated studies show that outcomes following eTICI 2c (90%-99% reperfusion) are superior to eTICI 2b50 and nearly equivalent to eTICI 3. Moreover, eTICI 2c improves scale reliability. Studies also confirm the importance of rapid revascularization, whether measured as first pass effect or procedural duration under 30 minutes. Distal embolization is a complication that impedes the extent and speed of revascularization, but few studies have reported its per-pass occurrence. Distal embolization and emboli to new territory should be measured after each thrombectomy maneuver. Collaterals have been shown to be an important modifier of thrombectomy benefit. A drawback of the currently accepted collateral grading scale is that it does not discriminate among the broad spectrum of partial collateralization. Important questions that require investigation include reasons for failed revascularization, the utility of a global Treatment in Cerebral Ischemia scale, and the optimal grading system for vertebrobasilar occlusions.

SUMMARY

Emerging data support a lead technical efficacy endpoint that combines the extent and speed of reperfusion. Efforts are needed to better characterize angiographic measures of treatment harm and of collateralization.

Predictors of Early Neurological Deterioration in Stroke Due to Vertebrobasilar Occlusion

Background and Aims: This study explores the predictors of early neurological deterioration (END) in patients with vertebrobasilar occlusion (VBO) in both primary endovascular therapy (EVT) and medical management (MM) groups. Methods: Patients diagnosed with VBO from 2010 to 2018 were included. Comparative and multivariate analyses were used to identify predictors of all-cause END in the EVT group, and END due to ischemia progression (END-IP) in the MM group. Results: In 174 patients with VBO, 43 had END. In the primary EVT group (N = 66), 17 all-cause END occurred. Distal basilar occlusion (odds ratio (OR), 14.5 [95% confidence interval (CI), 1.4-154.4]) and reperfusion failure (eTICI < 2b67 (OR, 5.0 [95% CI, 1.3-19.9]) were predictive of END in multivariable analysis. In the MM group (N=108), 17 END-IP occurred. Higher systolic blood pressure (SBP) at presentation (per 10 mmHg increase, OR, 1.5 [95% CI, 1.1-2.0]), stroke onset-to-door time <24 h (OR, 5.3 [95% CI, 1.1-2.0]), near-total occlusions (OR, 4.9 [95% CI, 1.2-19.6]), lower posterior circulation-Alberta Stroke Program Early CT scores (OR, 1.6 [95% CI, 1.0-2.5]), and lower BATMAN collateral scores (OR, 1.6 [95% CI, 1.1-2.2]) were predictive of END-IP. Conclusions: In patients with stroke due to VBO, potential predictors of END can be identified. In the primary EVT group, failure to achieve reperfusion and distal basilar occlusion were associated with all-cause END. In the MM group, higher SBP at presentation, onset-to-door time less than 24 h, incomplete occlusions, larger infarct cores, and poorer collaterals were associated with END-IP.

Transcirculation Embolization to New Territory During Mechanical Thrombectomy for Acute Ischemic Stroke

Embolization in new territories (ENT) is a known complication of mechanical thrombectomy with incidence dependent upon a variety of procedural factors. We present 2 cases of anterior circulation to posterior circulation ENT. These cases were managed with manual aspiration thrombectomy with excellent radiographic and clinical outcome. We present the available literature involving ENT along with our experience in management.

Thrombectomy for secondary distal, medium vessel occlusions of the posterior circulation: seeking complete reperfusion

BACKGROUND

Whether to approach distal occlusions endovascularly or not in medium-sized vessels secondary to proximal large vessel occlusion stroke remains unanswered.

OBJECTIVE

To investigates the technical feasibility and safety of thrombectomy for secondary posterior circulation distal, medium vessel occlusions (DMVO).

METHODS

TOPMOST (Treatment fOr Primary Medium vessel Occlusion STroke) is an international, retrospective, multicenter, observational registry of patients treated for distal cerebral artery occlusions. This study subanalysis endovascularly treated occlusions of the posterior cerebral artery in the P2 and P3 segment secondary preprocedural or periprocedural thrombus migration between January 2014 and June 2020. Technical feasibility was evaluated with the modified Thrombolysis in Cerebral Infarction (mTICI) scale. Procedural safety was assessed by the occurrence of symptomatic intracranial hemorrhage (sICH) and intervention-related serious adverse events.

RESULTS

Among 71 patients with secondary posterior circulation DMVO who met the inclusion criteria, occlusions were present in 80.3% (57/71) located in the P2 segment and in 19.7% (14/71) in the P3 segment. Periprocedural migration occurred in 54.9% (39/71) and preprocedural migration in 45.1% (32/71) of cases. The first reperfusion attempt led in 38% (27/71) of all cases to mTICI 3. On multivariable logistic regression analysis, increased numbers of reperfusion attempts (adjusted odds ratio (aOR)=0.39, 95% CI 0.29 to 0.88, p=0.009) and preprocedural migration (aOR=4.70, 95% CI,1.35 to 16.35, p=0.015) were significantly associated with mTICI 3. sICH occurred in 2.8% (2/71).

CONCLUSION

Thrombectomy for secondary posterior circulation DMVO seems to be safe and technically feasible. Even though thrombi that have migrated preprocedurally may be easier to retract, successful reperfusion can be achieved in the majority of patients with secondary DMVO of the P2 and P3 segment.

Stroke thrombectomy complication management

Endovascular mechanical thrombectomy (EVT) is widely accepted as the first-line treatment for acute ischemic stroke in patients with large vessel occlusion. Being an invasive treatment, this method is associated with various preoperative, perioperative, and postoperative complications. These complications may influence peri-interventional morbidity and mortality and therefore treatment efficacy and clinical outcome. The aim of this review is to discuss the most common types of complications associated with EVT, the probable mechanisms of injury, and effective methods to manage and prevent complications.

Approaching the Boundaries of Endovascular Treatment in Acute Ischemic Stroke : Multicenter Experience with Mechanical Thrombectomy in Vertebrobasilar Artery Branch Occlusions

PURPOSE

Little is known about catheter-based endovascular treatment of vertebrobasilar artery branch occlusion (VEBABO) in acute ischemic stroke (AIS). Nonetheless, the experience of mechanical thrombectomy (MT) in distal small sized arteries of the anterior circulation seems promising in AIS. In this multicenter study, we report the feasibility, efficacy and safety of MT in VEBABO.

METHODS

Retrospective analysis of consecutive AIS patients treated with MT due to VEBABO including posterior and anterior inferior cerebellar artery (PICA, AICA) and superior cerebellar artery (SCA) occlusions at seven tertiary care centers between January 2013 and May 2020. Baseline demographics and angiographic outcomes including recanalization success of the affected cerebellar arteries and procedural complications were recorded. Clinical outcomes were evaluated by the modified Rankin scale (mRS) at discharge and 90 days.

RESULTS

Out of 668 endovascularly treated posterior circulation strokes we identified 16 (0.02%) cases with MT for VEBABO. Most frequently, MT of the SCA was done (13/16, 81%). Most VEBABOs occurred after MT of initial basilar/posterior cerebral artery occlusion (9/16, 56%). In 10/16 (63%) procedures, the affected VEBABO was successfully recanalized. Out of four patients three (75%) with isolated VEBABO had benefited from endovascular therapy. Subarachnoid hemorrhage was observed in 3/16 (19%) procedures. The rate of favorable outcome (mRS ≤2) was 40% at discharge and 47% at 90-day follow-up. Mortality was 13% (2/15).

CONCLUSION

The use of MT for VEBABO is rare but appears to be feasible and effective; however, the comparatively high rate of procedure-related hemorrhage highlights that the indications for MT in these occlusion sites should be carefully weighed up.

Choice of ANaesthesia for EndoVAScular treatment of acute ischaemic stroke at posterior circulation (CANVAS II): protocol for an exploratory randomised controlled study

INTRODUCTION

Observational and interventional studies indicate that the type of anaesthesia may be associated with the postprocedural neurological function in patients with anterior circulation acute ischaemic stroke undergoing endovascular treatment. Patients with acute posterior circulation ischaemic stroke may experience different physiological changes and result in severe neurological outcome. However, the effect of the type of anaesthesia on postprocedure neurological function remained unclear in this population.

METHODS AND ANALYSIS

This is an exploratory randomised controlled trial that will be carried out at Beijing Tiantan Hospital, Capital Medical University. Patients with acute posterior circulation ischaemic stroke and deemed suitable for emergency endovascular recanalisation will be recruited in this trial. Eighty-four patients will be randomised to receive either general anaesthesia or conscious sedation with 1:1 allocation ratio. The primary endpoint is the 90-day modified Rankin Scale.

ETHICS AND DISSEMINATION

The study has been reviewed by and approved by Ethics Committee of Beijing Tiantan Hospital of Capital Medical University (KY2017-074-02). If the results are positive, the study will indicate whether the type of anaesthesia affects neurological outcome after endovascular treatment of posterior stroke. The findings of the study will be published in peer-reviewed journals and presented at national or international conferences.

TRIAL REGISTRATION NUMBER

NCT03317535.

Feasibility and safety of thrombectomy for isolated occlusions of the posterior cerebral artery: a multicenter experience and systematic literature review

BACKGROUND

Substantial clinical evidence supporting the benefit of mechanical thrombectomy (MT) for distal occlusions within the posterior circulation is still missing. This study aims to investigate the procedural feasibility and safety of MT for isolated occlusions of the posterior cerebral artery.

METHODS

We retrospectively reviewed patients from three stroke centers with acute ischemic stroke attributed to isolated posterior cerebral artery occlusion (IPCAOs) who underwent MT between January 2014 and December 2019. Procedural and safety assessment included successful recanalization rates (defined as Thrombolysis in Cerebral Infarction Scale (TICI) ≥2b), number of MT attempts and first-pass effect (TICI 3), intracranial hemorrhage (ICH), mortality, and intervention-related serious adverse events. Treatment effects were evaluated by the rate of early neurological improvement (ENI) and early functional outcome was assessed with the modified Rankin Scale (mRS) at discharge. A systematic literature review was conducted to identify and summarize previous reports on MT for IPCAOs.

RESULTS

Forty-three patients with IPCAOs located in the P1 (55.8%, 24/43), P2 (37.2%, 16/43), and P3 segment (7%, 3/43) were analyzed. The overall rate of successful recanalization (TICI ≥2b) was 86% (37/43), including a first pass-effect of 48.8% (21/43) leading to TICI 3. sICH occurred in 7% (3/43) and there were two cases with iatrogenic vessel dissection and one perforation. ENI was observed in 59% (23/39) and excellent functional outcome (mRS ≤1) in 46.2% (18/39) of patients who were discharged. The in-hospital mortality rate was 9.3% (4/43).

CONCLUSION

Our study suggests the technical feasibility and safety of thrombectomy for IPCAOs. Further studies are needed to investigate safety and long-term functional outcomes with posterior circulation stroke-adjusted outcome assessment.

Effect of Balloon Guide Catheter Utilization on the Incidence of Sub-angiographic Peripheral Emboli on High-Resolution DWI After Thrombectomy: A Prospective Observational Study

Background: Thrombus fragmentation causing distal emboli is a feared complication during mechanical thrombectomy (MT). We aimed to investigate the impact of procedural parameters and thrombus properties on the incidence of peripheral emboli after MT for large vessel occlusions (LVO).

Methods: We performed a prospective analysis of patients with LVO stroke successfully treated with MT, defined as a score of 2b, 2c, or 3 on the thrombolysis in cerebral infarction (TICI) scale. A follow-up MRI including high-resolution diffusion-weighted imaging (DWI) was performed within 24 h following MT. The primary endpoint was the number and volume of peripheral emboli, classified as punctuate DWI lesions distant to the diffusion-restricted core lesion. Further analysis included the influence of baseline characteristics, procedural and outcome parameters, and thrombus properties on peripheral emboli.

Results: Thirty-seven patients with successful MT met the inclusion criteria. Use of a balloon guide catheter (BGC) and TICI were the only independent predictors for a reduced number of peripheral emboli. The use of a BGC led to a significant reduction in the number and volume of peripheral emboli, with a median number/volume of peripheral emboli of 4.5/287 μl (IQR 1.25–8.25/76–569 μl) vs. 12/938 μl (IQR 4–19/242–1,836 μl). In cases where BGC was not employed, the number of peripheral emboli increased with decreasing TICI scores.

Conclusions: BGC-aided MT reduces the number of peripheral emboli in successful but incomplete reperfusion (TICI 2b and 2c). The effectiveness of this strategy therefore goes above and beyond that which can be demonstrated by the TICI score alone.

Mechanical thrombectomy for basilar artery occlusion: efficacy, outcomes, and futile recanalization in comparison with the anterior circulation

BACKGROUND

Performing mechanical thrombectomy (MT) in patients with basilar artery occlusion (BAO) is currently not evidence-based.

OBJECTIVE

To compare patients' outcome, relative merits of achieving recanalization, and predictors of futile recanalization (FR) between BAO and anterior circulation large vessel occlusion (ACLVO) MT.

METHODS

In the multicenter BEYOND-SWIFT registry (NCT03496064), univariate and multivariate (displayed as adjusted Odds Ratios, aOR and 95% confidence intervals, 95%-CI) outcome comparisons between BAO (N=165) and ACLVO (N=1574) were performed. The primary outcome was favorable outcome at 90 days (modified Rankin Scale, mRS 0-2). Secondary outcome included mortality, symptomatic intracranial hemorrhage (sICH) and FR. The relative merits of achieving successful recanalization between ACLVO and BAO were evaluated with interaction terms.

RESULTS

MT in BAO was more often technically effective and equally safe in regards to mortality and sICH when compared to ACLVO. When adjusting for baseline differences, there was no significant difference between BAO vs ACLVO regarding rates of favorable outcome (aOR 0.986, 95%-CI 0.553 - 1.758). However, BAO were associated with increased rates of FR (aOR 2.146, 95%-CI 1.267 - 3.633). Predictors for FR were age, stroke severity, maneuver count and intracranial stenting. No significant heterogeneity on the relative merits of achieving successful recanalization on several outcome parameters were observed when comparing BAO and ACLVO.

CONCLUSIONS

In selected patients, similar outcomes can be achieved in BAO and ACLVO patients treated with MT. Randomized controlled trials comparing patient selection and interventional strategies seem warranted to avoid FR.

TRIAL REGISTRATION NUMBER

NCT03496064.

Safety and Efficacy of Heparinization During Mechanical Thrombectomy in Acute Ischemic Stroke

Background: The benefits of heparization during mechanical thrombectomy (MT) with newer generation thrombectomy devices, and if it is counterbalanced by the increased risk of intracranial hemorrhage (ICH) remain unknown.

Methods: We included eligible patients who underwent MT from the ANGEL registry study (2015-2017) in China. Subjects in the current analysis were dichotomized into two groups according to whether adequate heparinization during MT was performed. In the heparinization group, unfractionated heparin was infused at 50–100 IU/Kg at first and additional 1,000 IU at intervals of an hour during the operation. Safety outcomes (symptomatic intracerebral hemorrhage [sICH], ICH and distal embolization) and efficacy outcomes (artery recanalization and functional outcomes at 3-month follow-up) were compared between groups.

Results: We included 619 patients from the entire cohort of 917 patients. The average age of them was 63.9 ± 13.7 years, 269 (43.5%) were treated with heparinization during MT. Heparinization during MT didn't significantly influence recanalization rates, total ICH and long-term mortality (adjusted p > 0.05 for all). But sICH and distal embolization occurred more frequently (9.3 vs. 5.1%, adjusted p = 0.02; 7.1 vs. 3.1%, adjusted p = 0.04, respectively), while functional independence appeared less likely (39.8 vs. 47.4%, adjusted p = 0.01) in heparinization group than that in non-heparinization group. Multivariable logistic regression analyses showed that heparinization during MT was an independent predictor for sICH (Odds ratio 2.36 [1.19–4.67], p = 0.01) in addition to cardio-embolism stroke and posterior circulation stroke (PCS), and an independent predictor for poor outcome (Odds ratio 1.79 [1.23–2.59], p < 0.01) besides age, bridging intravenous thrombolysis, admission NIHSS, drinking and PCS.

Conclusion: Heparinization during MT may be associated with increased risk of safety outcomes over sICH and distal embolization, as well as efficacy outcomes over long-term poor outcome. Further randomized controlled trials are needed.