Intravenous Thrombolysis and Passes of Thrombectomy as Predictors for Endovascular Revascularization in Ischemic Stroke

In a hub-and-spoke network, spoke-administered thrombolysis reduces mechanical thrombectomy procedure time and number of passes

BACKGROUND

The utility of intravenous thrombolysis (IVT) prior to mechanical thrombectomy (MT) in large vessel occlusion stroke (LVO) is controversial. Some data suggest IVT increases MT technical difficulty. Within our hub-and-spoke telestroke network, we examined how spoke-administered IVT affected hub MT procedure time and pass number.

METHODS

Patients presenting to 25 spoke hospitals who were transferred to the hub and underwent MT from 2018 to 2020 were identified from a prospectively maintained database. MT procedure time, fluoroscopy time, and pass number were obtained from operative reports.

RESULTS

Of 107 patients, 48 received IVT at spokes. Baseline characteristics and NIHSS were similar. The last known well (LKW)-to-puncture time was shorter among IVT patients (4.3 ± 1.9 h vs. 10.5 ± 6.5 h, p < 0.0001). In patients that received IVT, mean MT procedure time was decreased by 18.8 min (50.5 ± 29.4 vs. 69.3 ± 46.7 min, p = 0.02) and mean fluoroscopy time was decreased by 11.3 min (21.7 ± 15.8 vs. 33.0 ± 30.9 min, p = 0.03). Furthermore, IVT-treated patients required fewer MT passes (median 1 pass [IQR 1.0, 1.80] vs. 2 passes [1.0, 2.3], p = 0.0002) and were more likely to achieve reperfusion in ≤2 passes (81.3% vs. 59.3%, p = 0.01). An increased proportion of IVT-treated patients achieved TICI 2b-3 reperfusion after MT (93.9% vs. 83.8%, p = 0.045). There were no associations between MT procedural characteristics and LKW-to-puncture time.

CONCLUSION

Within our network, hub MT following spoke-administered IVT was faster, required fewer passes, and achieved improved reperfusion. This suggests spoke-administered IVT does not impair MT, but instead may enhance it.

Direct Mechanical Thrombectomy vs. Bridging Therapy in Stroke Patients in A “Stroke Belt” Region of Southern Europe

The aim of this 4-year observational study is to analyze the outcomes of stroke patients treated with direct mechanical thrombectomy (dMT) compared to bridging therapy (BT) (intravenous thrombolysis [IVT] + BT) based on 3-month outcomes, in real clinical practice in the "Stroke Belt" of Southern Europe. In total, 300 patients were included (41.3% dMT and 58.6% BT). The frequency of direct referral to the stroke center was similar in the dMT and BT group, whereas the time from onset to groin was longer in the BT group (median 210 [IQR 160–303] vs. 399 [IQR 225–675], p = 0.001). Successful recanalization (TICI 2b-3) and hemorrhagic transformation were similar in both groups. The BT group more frequently showed excellent outcomes at 3 months (32.4% vs. 15.4%, p = 0.004). Multivariate analysis showed that BT was independently associated with excellent outcomes (OR 2.7. 95% CI,1.2–5.9, p = 0.02) and lower mortality (OR 0.36. 95% CI 0.16–0.82, p = 015). Conclusions: Compared with dMT, BT was associated with excellent functional outcomes and lower 3-month mortality in this real-world clinical practice study conducted in a region belonging to the “Stroke Belt” of Southern Europe. Given the disparity of results on the benefit of BT in the current evidence, it is of vital importance to analyze the convenience of its use in each health area.

Predictive Factors for Clinical Outcome After Direct Mechanical Thrombectomy for Anterior Circulation Large Vessel Occlusion Within 4.5 h

Background

Recent trials including DIRECT-MT, DEVT, and SKIP have found that direct mechanical thrombectomy (MT) is equally effective as the combination of MT and intravenous thrombolysis. However, the results of the other trials, namely MR-CLEAN NO-IV and the SWIFT-DIRECT trial have failed to confirm the non-inferiority of direct MT vs. the combination therapy.

Aim

We aimed to identify prognostic factors of direct MT for anterior circulation large vessel occlusion within 4.5 h.

Materials and Methods

Data from January 2018 to January 2022 were retrospectively collected and analyzed. Adult patients with confirmed anterior circulation large vessel occlusion within 4.5 h of onset with baseline NIHSS of ≥6 and baseline ASPECTS of ≥6 treated using direct MT within 6 h were recruited.

Results

A total of 140 patients were enrolled in the study with a median age of 65.5 years [interquartile range (IQR), 59-76.5], median baseline NIHSS of 13.5 (IQR, 11-16), and median baseline ASPECTS of 8 (IQR, 7-8). Direct MT was feasible in all patients (100%). Successful reperfusion (mTICI 2b-3) was achieved in 124/140 patients (88.6%) with a low rate of complications (8/140, 5.7%). Any type of intracranial hemorrhage (ICH) and symptomatic ICH occurred in 44/140 (31.4%) and 5/140 (3.6%), respectively. Overall, a good outcome (mRS 0-2) was achieved in 93/140 (66.4%), and the mortality rate was 9.3% (13/140 patients). Using multivariate analysis, lower age [odds ratio (OR), 0.96; 95% CI, 0.92-1.00; P = 0.05], low baseline NIHSS (OR, 0.82; 95% CI, 0.74-0.92; P = 0.00), and absence of ICH (OR, 0.29; 95% CI, 0.10-0.81; P = 0.02) were independently associated with favorable outcome. Independent predictors of mortality were baseline NIHSS (OR, 1.21; 95% CI, 1.01-1.46; P = 0.04), successful reperfusion (OR, 0.02; 95% CI, 0.00-0.58; P = 0.02), and ICH (OR, 0.12; 95% CI, 0.02-0.75; P = 0.02). Further analysis showed that the median mRS at 90 days was significantly better in the MCA occlusion group compared to the ICA plus M1 occlusion group [1 (IQR 0-3) vs. 2 (IQR 1-4); P = 0.05].

Conclusions

Our findings suggest that direct thrombectomy may be an adequate clinical option for younger patients (≤70) experiencing proximal middle artery occlusion within 4.5 h and who have low baseline NIHSS (≤14).

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

BACKGROUND AND AIM

First pass effect (FPE) is defined as achieving a complete recanalization with a single thrombectomy device pass. Although clinically desired, FPE is reached in less than 30% of thrombectomy procedures. Multiple device passes are often necessary to achieve successful or complete recanalization. We performed a systematic review and meta-analysis to determine the recanalization rate after each pass of mechanical thrombectomy and its association with good neurological outcome.

METHODS

A literature search was performed for studies reporting the number of device passes required for either successful (mTICI 2b or higher) or complete (mTICI 2c or higher) recanalization. Using random-effect meta-analysis, we evaluated the likelihood of recanalization and good neurological outcome (measured with the modified Rankin Score <2 at 90 days) after each device pass.

RESULTS

Thirteen studies comprising 4197 patients were included. Among cases with failed first pass, 24% of them achieved final complete recanalization and 45% of them achieved final successful recanalization. Independently to the total number of previously failed attempts, the likelihood of achieving successful recanalization was 30% per pass, and the likelihood to achieve complete recanalization was about 20% per pass. The likelihood of good neurological outcome in patients with final successful recanalization decreased after each device pass: 55% after the first pass, 48% after the second pass, 42% after the third pass, 36% after the fourth pass, and 26% for 5 passes or more.

CONCLUSION

Each pass is associated with a stable likelihood of recanalization but a decreased likelihood of good neurological outcome.

Outcomes of Mechanical Thrombectomy for Acute Ischemic Stroke When Multiple Passes Are Required and Associated Risk Factors

INTRODUCTION

This study aimed to evaluate the outcomes of mechanical thrombectomy for acute ischemic stroke when multiple passes are required and to identify the associated risk factors.

METHODS

Consecutive patients with acute ischemic stroke treated with mechanical thrombectomy at the Neurology Department of Ninth People's Hospital and the Neurosurgery Department of Xinhua Hospital of Shanghai Jiao Tong University School of Medicine from 2013 to 2018 were included. Patients were divided into 2 groups: those who received ≤2 passes and those who received >2 passes. Outcomes of the 2 groups were compared. Multivariate linear regression was used to determine factors associated with the need for >2 passes. All patient data were reviewed retrospectively.

RESULTS

A total of 122 patients were included, of whom 83 patients required ≤2 passes and 39 patients required >2 passes. After adjusting for sex, atrial fibrillation history, smoking history, and involvement of middle cerebral artery and internal cerebral artery, the National Institutes of Health Stroke Scale (NIHSS) score was associated with a 1.08-times greater risk of >2 passes (95% confidence interval [CI]: 1.01-1.17), and internal carotid artery with a 5.13-times greater risk of >2 passes (95% CI: 1.02-25.69). Having more than 2 passes was associated with significantly higher 7-day (25.6% vs. 6%), 90-day mortality rates (34.2% vs. 16%) and a significantly lower recanalization rate (66.7% vs. 89.2%).

CONCLUSION

Needing more than 2 passes during mechanical thrombectomy is associated with poorer outcomes. Higher preprocedural NIHSS scores and internal carotid artery thrombi are associated with more than 2 passes.

Thrombectomy in basilar artery occlusions: impact of number of passes and futile reperfusion

BACKGROUND

The number of mechanical thrombectomy (MT) passes is strongly associated with angiographic reperfusion as well as clinical outcomes in patients with anterior circulation ischemic stroke. However, these associations have not been analyzed in patients with basilar artery occlusion (BAO). We investigated the influence of the number of MT passes on the degree of reperfusion and clinical outcomes, and compared outcome after ≤3 passes versus >3 passes.

METHODS

We used data from the prospective multicentric Endovascular Treatment in Ischemic Stroke (ETIS) Registry at 18 sites in France. Patients with BAO treated with MT were included. The primary outcome was a favorable outcome, defined as a modified Rankin Scale score of 0-3 at 90 days. We fit mixed multiple regression models, with center as a random effect.

RESULTS

We included 275 patients. Successful recanalization (modified Thrombolysis In Cerebral Infarction (mTICI) 2b-3) was achieved in 88.4%, and 41.8% had a favorable outcome. The odds ratio for favorable outcome with each pass above 1 was 0.41 (95% CI 0.23 to 0.73) and for recanalization (mTICI 2b-3) it was 0.70 (95% CI 0.57 to 0.87). In patients with ≤3 passes, the rate of favorable outcome in recanalized versus non-recanalized patients was 50.5% versus 10.0% (p=0.001), while in those with >3 passes it was 16.7% versus 15.2% (p=0.901).

CONCLUSIONS

We found that BAO patients had a significant relationship between the number of MT passes and both recanalization and favorable functional outcome. We further found that the benefit of recanalization in BAO patients was significant only when recanalization was achieved within three passes, encouraging at least three passes before stopping the procedure.

Selecting the Appropriate First-Line Strategy Based on Hyperdense Vessel Sign in Acute Ischemic Stroke Increases First Pass Recanalization: A Tertiary Center Experience

Background:  The data pertaining to selecting an optimal first-line strategy (stent retriever [SR] vs. contact aspiration [CA]) based on noncontrast computed tomography (NCCT) in cases of acute ischemic stroke consequent to large vessel occlusion (LVO) is lacking.

Aims:  This article studies the influence of hyperdense vessel sign (HVS) in selecting optimal first-line strategy, with intention of increasing first-pass recanalization (FPR).

Methods:  Upfront approach at our center is SR technique with rescue therapy (CA) adoption consequent to three failed SR attempts to achieve successful recanalization. Data of patients with acute LVO who underwent mechanical thrombectomy from June 2017 to May 2020 was retrospectively analyzed. Patients were classified into HVS (+) and HVS (−) cohort. Rate of successful recanalization (first pass, early, and final) and efficacy of rescue therapy was assessed between the two cohorts.

Results:  Of 52 patients included, 28 and 24 were assigned to the HVS (+) and HVS (−) cohort, respectively. FPR was observed in 50% of HVS (+) and 20.9% of HVS (−) ( p  = 0.029). Early recanalization was documented in 64.2% of HVS (+) and 37.5% of HVS (−) ( p  = 0.054). Rescue therapy need was higher in patients not demonstrating HVS ( p  = 0.062). Successful recanalization was achieved with rescue therapy in 50% of HVS (−) group.

Conclusion:  A higher FPR is achievable following individualized first-pass strategy (based on NCCT appearance of clot), instead of a generalized SR first-pass approach. This CT imaging-based strategy is a step closer to achieving primary angiographic goal of FPR.

Effect of Intravenous Thrombolysis on Clot Survival during Mechanical Thrombectomy in Acute Large Vessel Occlusion Strokes

BACKGROUND

The benefit of intravenous thrombolysis (IVT) before mechanical thrombectomy (MT) in patients with large vessel occlusion (LVO) stroke is uncertain. Conventional metrics of final modified thrombolysis in cerebral ischemia (mTICI) score and 90-d modified Rankin Scale may be insensitive to IVT effects on procedural complexity and duration.

OBJECTIVE

To study the effect of IVT prior to MT on clot survival.

METHODS

We performed a single-center retrospective analysis of 257 acute stroke patients with LVO undergoing MT and analyzed the effect of IVT prior to MT using a novel, pass-by-pass clot survival methodology.

RESULTS

The use of IVT was associated with a significantly lower number of passes to attain mTICI 2B or greater (P = .002) or mTICI 3 (P = .039) reperfusion. The number of patients who achieved mTICI 2B or greater after the first pass was significantly higher in the IVT group (P = .003). This increased rate of reperfusion persisted into subsequent passes.

CONCLUSION

IVT prior to MT reduces the number of thrombectomy passes required to achieve mTICI 2B or mTICI 3 reperfusion. This information should be considered as the merits of IVT prior to MT are debated.

Stroke Etiology and Outcomes after Endovascular Thrombectomy: Results from the SITS Registry and a Meta-Analysis

BACKGROUND AND PURPOSE

The influence of stroke etiology on outcomes after endovascular thrombectomy (EVT) is not well understood. We aimed to investigate whether stroke etiology subgrouped as large artery atherosclerosis (LAA) and cardiac embolism (CE) influences outcomes in large artery occlusion (LAO) treated by EVT.

METHODS

We included EVT treated LAO stroke patients registered in the Safe Implementation of Treatment in Stroke (SITS) thrombectomy register between January 1, 2014 and September 3, 2019. Primary outcome was successful reperfusion (modified Treatment in Cerebral Infarction 2b-3). Secondary outcomes were symptomatic intracranial hemorrhage (SICH), 3-month functional independence (modified Ranking Scale 0-2) and death. Multivariable logistic regression models were used for comparisons. In addition, a meta-analysis of aggregate data from the current literature was conducted (PROSPERO, ID 167447).

RESULTS

Of 7,543 patients, 1,903 (25.2%) had LAA, 3,214 (42.6%) CE, and 2,426 (32.2%) unknown, other, or multiple etiologies. LAA patients were younger (66 vs. 74, P<0.001) and had lower National Institutes of Health Stroke Scale score at baseline (15 vs. 16, P<0.001) than CE patients. Multivariable analyses showed that LAA patients had lower odds of successful reperfusion (odds ratio [OR], 0.70; 95% confidence interval [CI], 0.57 to 0.86) and functional independence (OR, 0.74; 95% CI, 0.63 to 0.85), higher risk of death (OR, 1.44; 95% CI, 1.21 to 1.71), but no difference in SICH (OR, 1.09; 95% CI, 0.71 to 1.66) compared to CE patients. The systematic review found 25 studies matching the criteria. The meta-analysis did not find any difference between etiologies.

CONCLUSIONS

From the SITS thrombectomy register, we observed a lower chance of reperfusion and worse outcomes after thrombectomy in patients with LAA compared to CE etiology, despite more favorable baseline characteristics. In contrast, the meta-analysis did not find any difference between etiologies with aggregate data.

Comparison of Prior Bridging Intravenous Thrombolysis With Direct Endovascular Thrombectomy for Anterior Circulation Large Vessel Occlusion: Systematic Review and Meta-Analysis

Background: Whether bridging treatment combining intravenous thrombolysis (IVT) and endovascular thrombectomy (EVT) is superior to direct EVT alone for emergent large vessel occlusion (LVO) in the anterior circulation is unknown. A systematic review and a meta-analysis were performed to investigate and assess the effect and safety of bridging treatment vs. direct EVT in patients with LVO in the anterior circulation.

Methods: PubMed, EMBASE, and the Cochrane library were searched to assess the effect and safety of bridging treatment and direct EVT in LVO. Functional independence, mortality, asymptomatic and symptomatic intracranial hemorrhage (aICH and sICH, respectively), and successful recanalization were evaluated. The risk ratio and the 95% CI were analyzed.

Results: Among the eight studies included, there was no significant difference in the long-term functional independence (OR = 1.008, 95% CI = 0.845–1.204, P = 0.926), mortality (OR = 1.060, 95% CI = 0.840–1.336, P = 0.624), recanalization rate (OR = 1.015, 95% CI = 0.793–1.300, P = 0.905), and the incidence of sICH (OR = 1.320, 95% CI = 0.931–1.870, P = 0.119) between bridging therapy and direct EVT. After adjusting for confounding factors, bridging therapy showed a lower recanalization rate (effect size or ES = −0.377, 95% CI = −0.684 to −0.070, P = 0.016), but there was no significant difference in the long-term functional independence (ES = 0.057, 95% CI = −0.177 to 0.291, P = 0.634), mortality (ES = 0.693, 95% CI = −0.133 to 1.519, P = 0.100), and incidence of sICH (ES = −0.051, 95% CI = −0.687 to 0.585, P = 0.875) compared with direct EVT. Meanwhile, in the subgroup analysis of RCT, no significant difference was found in the long-term functional independence (OR = 0.927, 95% CI = 0.727–1.182, P = 0.539), recanalization rate (OR = 1.331, 95% CI = 0.948–1.867, P = 0.099), mortality (OR = 1.072, 95% CI = 0.776–1.481, P = 0.673), and sICH incidence (OR = 1.383, 95% CI = 0.806–2.374, P = 0.977) between patients receiving bridging therapy and those receiving direct DVT.

Conclusion: For stroke patients with acute anterior circulation occlusion and who are eligible for intravenous thrombolysis, there is no significant difference in the clinical effect between direct EVT and bridging therapy, which needs to be verified by more randomized controlled trials.

Prediction of mTICI 3 recanalization and clinical outcomes in endovascular thrombectomy for acute ischemic stroke: a retrospective study in the Taiwan registry

PURPOSE

Early recanalization for acute ischemic stroke (AIS) due to large vessel occlusion (LVO) by endovascular thrombectomy (EVT) is strongly related to improved functional outcomes. With data obtained from the Taiwan registry, the factors associated with mTICI 3 recanalization and clinical outcomes in EVT are investigated.

METHODS

From January 2014 to September 2016, 108 patients who underwent EVT for AIS due to LVO in 11 medical centers throughout Taiwan were included. Complete recanalization is defined as achieving modified thrombolysis in cerebral infarction (mTICI) grade 3. Good clinical outcomes are defined by the modified Rankin scale (mRS) 0-2 at 3 months after EVT. Clinical and imaging parameters for predicting mTICI 3 recanalization and good clinical outcomes are analyzed.

RESULTS

Of the 108 patients who received EVT, 54 (50%) patients had mTICI 3 recanalization. Having received aspiration only and the use of IV-tPA are shown to be significant predictors for mTICI 3 recanalization with odds ratios of 2.61 and 2.53 respectively. Forty-six (42.6%) patients experienced good 3-month clinical outcomes (mRS 0-2). Pretreatment collateral statuses, NIHSS scores, time lapses between symptoms to needle, and the occurrence of hemorrhage at 24 h are all significant predictors for good outcomes with odds ratios of 2.88, 0.91, 0.99, and 0.31 respectively.

CONCLUSIONS

Prediction of mTICI 3 recanalization and clinical outcomes offer valuable clinical information for treatment planning in EVT.

A meta-analysis of collateral status and outcomes of mechanical thrombectomy

OBJECTIVES

To perform a systematic review and meta-analysis to investigate pretreatment collaterals and outcomes of mechanical thrombectomy in patients with acute ischemic stroke of large-vessel occlusion in anterior circulation.

METHODS

We systematically searched Embase, PubMed, and the Cochrane Library from their dates of inception to March 5, 2020, and also manually searched reference lists of relevant articles. Pooled relative risk with 95% confidence interval on the association between good collaterals and functional independence (in terms of mRS 0-2), symptomatic intracranial hemorrhage, mortality, and successful reperfusion were synthesized using a random-effects model.

RESULTS

Thirty-four studies enrolling 5768 patients were included in analysis. Good collaterals were significantly associated with functional independence (RR 1.93, 95%CI 1.64-2.27, P < .0001), successful reperfusion (RR 1.23, 95%CI 1.12-1.35, P < .0001), decreased rate of symptomatic intracranial hemorrhage (RR 0.68, 95%CI 0.47-0.97, P = .032), and mortality (RR 0.37, 95%CI 0.27-0.52, P < .0001). The results were consistent in sensitivity analysis. The associations between good collaterals and reperfusion remained stable after adjusting for publication bias.

CONCLUSIONS

Good pretreatment collaterals were associated with functional independence, successful reperfusion, and decreased rate of sICH and mortality after receiving mechanical thrombectomy in patients with acute ischemic stroke of large-vessel occlusion.

More than five stentriever passes: real benefit or futile recanalization?

BACKGROUND AND AIMS

Clot extraction is associated with favorable outcome in patients with large vessel occlusions (LVO) undergoing endovascular thrombectomy (EVT). However, whether revascularization becomes futile or harmful with an increasing number of passes remains unknown.

METHODS

We performed a retrospective analysis of 271 consecutive patients with LVO who underwent stentriever-based EVT as the primary recanalization strategy. Primary outcomes including favorable recanalization, survival, and favorable functional outcomes were compared according to a dichotomized number of stentriever passes utilized with a cutoff of 4.

RESULTS

In the entire cohort, 234 (86%) patients reached favorable recanalization and 46 (17%) patients had ≥ 5 passes (range 5-40). Patients that had ≤ 4 passes had significantly higher rates of favorable recanalization and favorable outcomes and a trend towards lower mortality rates compared with those that had ≥ 5 stentriever passes (92% vs. 61%; p < 0.001, 52% vs. 30%; p = 0.009 and 12% vs. 22%, p = 0.098). Among patients that received ≥ 5 stentriever passes, 30% reached favorable outcomes. Patients who achieved recanalization after ≥ 5 passes had higher rates of favorable outcome in comparison with those who did not (p = 0.009). Among patients that had ≥ 5 stentriever passes favorable recanalization (OR 97.3, 95%CI 2.8-3399.3) and admission NIHSS (OR 0.77, 95%CI 0.60-0.99) remained independent predictors of favorable outcome, whereas the number of passes did not.

CONCLUSIONS

A substantial proportion of patients reach favorable outcomes even when ≥ 5 stentriever passes are performed. Treatment choices should be individualized based on personal preferences and expertise as well as on patient and clot-specific characteristics.

Value of thrombus imaging in predicting the outcomes of patients with large-vessel occlusive strokes after endovascular therapy

BACKGROUND

Acute ischemic stroke leads to serious long-term disability and high mortality, especially in patients with large-vessel occlusive strokes. Nowadays, endovascular therapy is considered as an alternative treatment for these patients. Several studies have used thrombus characteristics based on non-contrast computed tomography (NCCT) and computed tomography angiography (CTA) to predict prognosis in ischemic stroke. We conducted a systematic review to identify potential imaging predictive factors for successful recanalization and improved clinical outcome after endovascular therapy in patients with large-vessel occlusion (LVO) in anterior arterial circulation.

METHODS

The PubMed databases were searched for related studies reported between September 18, 2009, and September 18, 2019.

RESULTS

We selected 11 studies on revascularization and 12 studies on clinical outcome. Patients with thrombus of higher Hounsfield unit (HU), shorter length, higher clot burden score, and increased thrombus permeability may achieve higher recanalization and improved clinical outcome, but the matter is still under debate.

CONCLUSION

Imaging of thrombus can be used as an aseessment tool to predict the outcomes and it needs further studies in the future.

Intravenous thrombolysis pretreatment and other predictors of infarct in a new previously unaffected territory (INT) in ELVO strokes treated with mechanical thrombectomy

INTRODUCTION

One uncommon complication of mechanical thrombectomy (MT) is an infarct in a new previously unaffected territory (infarct in new territory (INT)).

OBJECTIVE

To evaluate the predictors of INT with special focus on intravenous thrombolysis(IVT)pretreatmentbefore MT.

METHODS

Consecutive patients with emergent large vessel occlusion (ELVO) treated with MT during a 5-year period were evaluated. INT was defined using standardized methodology proposed by ESCAPE investigators. The predictors of INT and its impact on outcomes were investigated.

RESULTS

A total of 419 consecutive patients with ELVO received MT (mean age 64±15 years, 50% men, median baseline National Institutes of Health Stroke Scale score 16 points (IQR 11-20), 69% pretreated with IVT). The incidence of INT was lower in patients treated with combination therapy (IVTandMT) than in patients treated with MT alone, respectively (10% vs 20%; p=0.011). The INT group had more patients with posterior circulation occlusions than the group without INT (28% vs 10%, respectively; p<0.001). The rates of 3-month functional independence were lower in patients with INT (30% vs 50%; p=0.007). IVT pretreatment was not independently related to INT (OR=0.75; 95% CI 0.32 to 1.76), and INT did not emerge as an independent predictor of 3-month functional independence (OR=0.69; 95% CI 0.29 to 1.62) on multivariable logistic regression models. Location of posterior circulation occlusion was independently associated with a higher odds of INT (OR=3.33; 95% CI 1.43 to 7.69; p=0.005).

CONCLUSIONS

IVT pretreatment is not independently associated with a lower likelihood of INT in patients with ELVO treated with MT. Patients with ELVO with posterior circulation occlusion are more likely to have INT after MT.

Combined intravenous and endovascular treatment versus primary mechanical thrombectomy. The Italian Registry of Endovascular Treatment in Acute Stroke

Background

Whether mechanical thrombectomy alone may achieve better or at least equal clinical outcome than mechanical thrombectomy combined with intravenous thrombolysis is a matter of debate.

Methods

From the Italian Registry of Endovascular Stroke Treatment, we extracted all cases treated with intravenous thrombolysis followed by mechanical thrombectomy or with primary mechanical thrombectomy for anterior circulation stroke due to proximal vessel occlusion. We included only patients who would have qualified for intravenous thrombolysis. We compared outcomes of the two groups by using multivariate regression analysis and propensity score method.

Results

We included 1148 patients, treated with combined intravenous thrombolysis and mechanical thrombectomy therapy (n = 635; 55.3%), or with mechanical thrombectomy alone (n = 513; 44.7%). Demographic and baseline clinical characteristics did not differ between the two groups, except for a shorter onset to groin puncture time (p < 0.05) in the mechanical thrombectomy group. A shift in the 90-day modified Rankin Scale distributions toward a better outcome was found in favor of the combined treatment (adjusted common odds ratio  = 1.3; 95% confidence interval: 1.04–1.66). Multivariate analyses on binary outcome show that subjects who underwent combined treatment had higher probability to survive with modified Rankin Scale 0–3 (odds ratio = 1.42; 95% confidence interval: 1.04–1.95) and lower case fatality rate (odds ratio = 0.6; 95% confidence interval: 0.44–0.9). Hemorrhagic transformation did not differ between the two groups.

Conclusion

These data seem to indicate that combined intravenous thrombolysis and mechanical thrombectomy could be associated with lower probability of death or severe dependency after three months from stroke due to large vessel occlusion, supporting the current guidelines of treating eligible patients with intravenous thrombolysis before mechanical thrombectomy.

Impact of pretreatment with intravenous thrombolysis on reperfusion status in acute strokes treated with mechanical thrombectomy

Introduction

We sought to evaluate the impact of pretreatment with intravenous thrombolysis (IVT) on the rate and speed of successful reperfusion (SR) in patients with emergent large vessel occlusion (ELVO) treated with mechanical thrombectomy (MT) in a high-volume tertiary care stroke center.

Methods

Consecutive patients with ELVO treated with MT were evaluated. Outcomes were compared between patients who underwent combined IVT and MT (IVT+MT) and those treated with direct MT (dMT). The elapsed time between groin puncture to beginning of reperfusion (GPTBRT) and the numbers of device passes required to achieve SR were also documented.

Results

A total of 287 and 132 patients were treated with IVT+MT and dMT, respectively. The IVT+MT group had higher SR (73.8% vs 62.9%; p=0.023) and 3-month functional independence (modified Rankin Scale score 0–2;51.6% vs 38.2%; p=0.008) rates. The median GPTBRT was shorter in the IVT+MT group (48 (IQR 33–70) vs 70 (IQR 44–98) min; p<0.001). Among patients who achieved SR (n=292), the median number of required device passes was lower in the IVT+MT subgroup (1 (IQR 1–1) vs 2 (IQR 1–2); p<0.001), while the rate of patients requiring ≤2 device passes was higher (98% vs 77%; p<0.001). IVT+MT was independently related to higher odds of SR (OR 1.64; 95% CI 1.03 to 2.61; p=0.036) and shorter GPTBRT (unstandardized linear regression coefficient −20.39; 95% CI −27.56 to –13.22; p<0.001) on multivariable analyses adjusting for potential confounders. Among patients with SR, IVT+MT was independently associated with a higher likelihood of ≤2 device passes (OR 14.63; 95% CI 4.46 to 48.00; p<0.001).

Conclusions

IVT pretreatment appears to increase the rates of SR and shortens the duration of the endovascular procedure by requiring fewer device passes in patients with ELVO treated with MT.

Effectiveness of Low-Dose Intravenous Tissue Plasminogen Activator before Stent Retriever or Aspiration Mechanical Thrombectomy

PURPOSE

To determine whether thrombolysis with a lower dose of intravenous recombinant tissue plasminogen activator before mechanical thrombectomy is beneficial for functional outcomes compared with mechanical thrombectomy alone.

MATERIALS AND METHODS

Data for 100 Japanese patients who underwent mechanical thrombectomy between July 2014 and November 2017 were retrospectively reviewed. These patients were divided into groups according to whether they received intravenous thrombolysis before mechanical thrombectomy, and outcomes were compared. Favorable outcome was defined as a modified Rankin scale score ≤ 2 at 3 months after treatment.

RESULTS

Thirty-four patients for the thrombolysis group and 66 patients for the thrombectomy-only group were identified. The thrombolysis and nonthrombolysis groups did not differ significantly in baseline characteristics (mean age, 74.3 y vs 75.7 y [P = .485]; mean preoperative National Institute Health Stroke Scale score, 19.8 vs 19.6 [P = .825]). There were no significant differences in the times required for, or the rates of, successful recanalization. However, the thrombolysis group had a higher rate of complete recanalization (67.6% vs 43.9%; P = .041). Postoperative symptomatic intracranial hemorrhage was not significantly different between groups. Favorable outcomes were observed in 73.5% of patients in the thrombolysis group and 51.5% in the nonthrombolysis group (P = .028).

CONCLUSIONS

This single-center retrospective study shows that lower-dose intravenous thrombolysis improves the outcomes of mechanical thrombectomy for Japanese patients with acute anterior-circulation stroke treated within 4.5 hours of onset.

More than three passes of stent retriever is an independent predictor of parenchymal hematoma in acute ischemic stroke

Introduction

Despite successful recanalization with mechanical thrombectomy (MT) for acute anterior ischemic stroke (AAIS), the number of passes may impact clinical outcome.

We analyzed the impact of more than three MT passes (>3) in a trial that evaluated contact aspiration (CA) versus stent retriever (SR) as the first-line technique in AAIS.

Methods

We included patients with mTICI 2b/3 recanalization after MT for isolated intracranial occlusions. The primary outcome was the percentage of patients with a 90-day modified Rankin Scale (mRS)≤2. Secondary outcomes included overall distribution of 90-day mRS, parenchymal hematoma on 24 hours' brain imaging (PH), and 90-day mortality.

Results

Among the 281 patients included and even after adjustment on time to recanalization, significantly more patients with >3 passes had PH than patients with ≤3 passes in multivariate analysis (adjusted OR, 3.62; 95% CI, 1.55 to 8.44). When the analyses were stratified according to CA vs. SR, patients with >3 passes had a stronger risk of PH than patients with ≤3 passes, only in the SR first-line-treated group (adjusted OR, 9.24; 95% CI, 2.65 to 32.13) and not in the CA first-line-treated group (adjusted RR, 1.73; 95% CI, 0.57 to 5.19). A negative association of borderline significance (P=0.07) between >3 passes and favorable outcome was observed only in SR first-line-treated patients (adjusted OR, 0.33; 95% CI, 0.09 to 1.11).

Conclusions

After three passes of SR and unlike for three passes of CA, there is an increased risk of PH and a trend toward a worse clinical outcome.

Susceptibility vessel sign on MRI predicts better clinical outcome in patients with anterior circulation acute stroke treated with stent retriever as first-line strategy

BACKGROUND

Susceptibility vessel sign (SVS) can be a useful MRI biomarker of an occlusion but its relationship with clinical outcomes of acute ischemic stroke (AIS) is yet to be fully elucidated.

OBJECTIVE

To investigate SVS in relation to the clinical outcomes after mechanical thrombectomy using a stent retriever (SR) as first-line approach in patients with AIS.

MATERIAL AND METHODS

We included patients with a first-line SR approach for anterior AIS from the the Contact Aspiration vs Stent Retriever for Successful Revascularization (ASTER) and THRombectomie des Artères CErebrales (THRACE) trials when both baseline imaging of SVS and 90-day modified Rankin Scale (mRS) scores were available. Patients were assigned to two groups based on the presence of an SVS (independent core laboratory), and the overall distributions of the mRS score at 90 days (shift analysis) and clinical independence (mRS score ≤2) were compared.

RESULTS

217 patients were included and SVS was diagnosed in 76.0% of cases (n=165, 95% CI 70.4% to 81.7%). After adjustment for potential confounders, SVS+ was significantly associated with 90-day mRS improvement (adjusted common OR=2.75; 95% CI 1.44 to 5.26) and favorable outcome (adjusted common OR=2.76; 95% CI 1.18 to 6.45).

CONCLUSION

Based on results for patients of the ASTER and THRACE trials receiving first-line SR treatment, SVS was associated with lower disability at 3 months. Large prospective studies using MRI-based thrombus evaluation are warranted.

Susceptibility Vessel Sign in the ASTER Trial: Higher Recanalization Rate and More Favourable Clinical Outcome after First Line Stent Retriever Compared to Contact Aspiration

Background and Purpose

In the Aspiration vs. Stent Retriever for Successful Revascularization (ASTER) trial, which evaluated contact aspiration (CA) versus stent retriever (SR) use as first-line technique, the impact of the susceptibility vessel sign (SVS) on magnetic resonance imaging (MRI) was studied to determine its influence on trial results.

Methods

We included patients having undergone CA or SR for M1 or M2 occlusions, who were screened by MRI with T2^* gradient recalled echo. Occlusions were classified as SVS (+) or SVS (–) in each randomization arm. Modified thrombolysis in cerebral infarction (mTICI) 2b, 2c, or 3 revascularization rates were recorded and clinical outcomes assessed by the overall distribution of modified Rankin scale (mRS) at 90 days.

Results

Among the 202 patients included, 143 patients were SVS (+) (70.8%; 95% confidence interval [CI], 64.5% to 77.1%). Overall, there was no difference in angiographic and clinical outcomes according to SVS status. However, compared to SR, CA achieved a lower mTICI 2c/3 rate in SVS (+) patients (risk ratio [RR] for CA vs. SR, 0.60; 95% CI, 0.51 to 0.71) but not in SVS (–) (RR, 1.11; 95% CI, 0.69 to 1.77; P for interaction=0.018). A significant heterogeneity in favor of superiority of first-line SR strategy in SVS (+) patients was also found regarding the overall mRS distribution (common odds ratio for CA vs. SR, 0.40 vs. 1.32; 95% CI, 0.21 to 0.74 in SVS (+) vs. 95% CI, 0.51 to 3.35 in SVS (–); P for interaction=0.038).

Conclusions

As a first line strategy, SR achieved higher recanalization rates and a more favourable clinical outcome at 3 months compared to CA when MRI shows SVS within the thrombus.

Predictive value of thrombus volume for recanalization in stent retriever thrombectomy

This retrospective study investigated whether the volume or density of the thrombus is predictive of recanalization in stent retriever (SR) treatment. Consecutive patients treated with SR thrombectomy as the first endovascular modality were enrolled. The thrombus volume and density were measured on thin-section noncontrast computed tomography using 3-dimensional software. The patients were grouped by recanalization status and the number of SR passes. Among 165 patients, recanalization was achieved with the first pass in 68 (50.0%), 2–3 passes in 43 (31.6%), and ≥4 passes in 25 (18.4%) patients. The thrombus volume was smaller in patients with (107.5 mm³) than without (173.7 mm³, p = 0.025) recanalization, and tended to be larger with increasing number of passes (p for trend = 0.001). The thrombus volume was an independent predictor of first-pass recanalization (odds ratio 0.93 per 10 mm³, 95% confidence interval 0.89–0.97). However, the thrombus density was not associated with recanalization success. Recanalization within 3 passes was associated with a favorable outcome. In conclusion, the thrombus volume was significantly related to recanalization in SR thrombectomy. Measuring the thrombus volume was particularly predictive of first-pass recanalization, which was associated with a higher likelihood of a favorable outcome.

Direct Mechanical Intervention Versus Bridging Therapy in Stroke Patients Eligible for Intravenous Thrombolysis: A Pooled Analysis of 2 Registries

BACKGROUND AND PURPOSE

Randomized controlled trials have shown that mechanical thrombectomy (MT) plus best medical treatment improves outcome in stroke patients with large-vessel occlusion in the anterior circulation. Whether direct MT is equally effective as bridging thrombolysis (intravenous thrombolysis plus MT) in intravenous thrombolysis eligible patients remains unclear.

METHODS

We compared clinical and radiological outcomes at 3 months in 249 bridging patients with 111 patients receiving direct MT for large-vessel occlusion anterior circulation stroke from 2 prospective registries (study period Essen: June 2012 to August 2013, Bern February 2009 to August 2014). We matched all patients from the direct MT group who would have qualified for intravenous thrombolysis with controls from the bridging group, using multivariate and propensity score methods. Subgroup analyses for internal carotid artery occlusions were performed.

RESULTS

Baseline characteristics did not differ between the direct MT group and bridging cohort, except for higher rates of coronary heart disease (P=0.029) and shorter intervals from onset to endovascular therapy (P<0.001) in the MT group. Functional outcome, mortality, and intracerebral hemorrhage did not differ, neither in univariate nor after multivariate and propensity score matching. However, in patients with internal carotid artery occlusion, mortality in the direct cohort was significantly lower.

CONCLUSIONS

In this matched-pair analysis, there was no difference in outcome in patients with large-vessel occlusion anterior circulation stroke treated with direct MT compared with those treated with bridging thrombolysis; however, mortality in patients with internal carotid artery occlusion treated with direct MT was significantly lower than after bridging thrombolysis. Randomized trials comparing direct MT with bridging therapy are needed.

Effect of Retrievable Stent Size on Endovascular Treatment of Acute Ischemic Stroke: A Multicenter Study

BACKGROUND AND PURPOSE

In clinical practice, stent diameter is one of the variable properties important for endovascular treatment. A consensus guideline for stent retriever size selection has yet to be established. The aim of this study was to investigate the effects of different diameters of Solitaire retrievers on outcomes.

MATERIALS AND METHODS

Of 628 patients enrolled from the Endovascular Treatment for Acute Anterior Circulation Ischemic Stroke Registry, 256 were treated with the Solitaire 4-mm device and 372, with the 6-mm device. We matched patients treated with the 2 stent sizes using propensity score analysis. The successful outcome was reperfusion as measured by the modified Thrombolysis in Cerebral Infarction score immediately postprocedure and the dichotomized modified Rankin Scale score at 90 days. Symptomatic intracerebral hemorrhage and in-hospital mortality were also recorded.

RESULTS

After propensity score analysis, group outcomes did not differ. In addition, in patients with atherosclerosis-related occlusion, a higher reperfusion rate (P = .021) was observed in the Solitaire 4 group, as well as a shorter time interval (P = .002) and fewer passes (P = .025). Independent predictors of successful reperfusion in patients with atherosclerotic disease on logistic analysis were the small stent (OR, 3.217; 95% CI, 1.129-9.162; P = .029) and the propensity score acting as a covariate (OR, 52.84; 95% CI, 3.468-805.018; P = .004).

CONCLUSIONS

We found no evidence of a differential effect of intra-arterial therapy based on the size of Solitaire retrievers. In patients with atherosclerotic disease, favorable reperfusion was associated with deployment of a small stent.

MRI quantitative T2* mapping on thrombus to predict recanalization after endovascular treatment for acute anterior ischemic stroke

BACKGROUND

In anterior acute ischemic stroke (AAIS) treated with endovascular treatment (EVT), the susceptibility vessel sign (SVS+ or SVS-) is related to recanalization results (TICI 2b/3) and clinical outcome. However, a binary qualitative assessment of thrombus using SVS does not reflect its complex composition. Our aim was to assess whether a quantitative MRI marker, Thrombus-T2* relaxation time, may be assessable in clinical routine and may to predict early successful recanalization after EVT, defined as a TICI 2b/3 recanalization obtained in 2 attempts or less.

MATERIAL AND METHODS

Thrombus-T2* relaxation time was prospectively obtained from consecutive AAIS patients treated by EVT (concomitant aspiration and stent retriever). Quantitative values were compared between early recanalization and late or unsuccessful recanalization.

RESULTS

Thirty patients with AAIS were included and Thrombus-T2* relaxation time was obtained in all patients. Earlier TICI 2b/3 recanalization were obtained in 22 patients (73%) and was significantly associated with SVS+ (1/8 vs. 16/22, P=0.01) and a shorter Thombus-T2* relaxation time (mean SD, range: 257, 18-50ms vs. 45 9, 35-60ms, P<0.001).

CONCLUSION

A new quantitative MRI biomarker, the Thrombus-T2* relaxation time is assessable in clinical routine. In a preliminary study of 30 patients, a shorter Thombus-T2* relaxation time is related to earlier recanalization after EVT using combination of stent retriever and aspiration.

Computed Tomography-Based Thrombus Imaging for the Prediction of Recanalization after Reperfusion Therapy in Stroke

The prediction of successful recanalization following thrombolytic or endovascular treatment may be helpful to determine the strategy of recanalization treatment in acute stroke. Thrombus can be detected using noncontrast computed tomography (CT) as a hyperdense artery sign or blooming artifact on a T2^*-weighted gradient-recalled image. The detection of thrombus using CT depends on slice thickness. Thrombus burden can be determined in terms of the length, volume, and clot burden score. The thrombus size can be quantitatively measured on thin-section CT or CT angiography/magnetic resonance angiography. The determination of thrombus size may be predictive of successful recanalization/non-recanalization after intravenous thrombolysis and endovascular treatment. However, cut-offs of thrombus size for predicting recanalization/non-recanalization are different among studies, due to different methods of measurements. Thus, a standardized method to measure the thrombus is necessary for thrombus imaging to be useful and reliable in clinical practice. Software-based measurements may provide a reliable and accurate assessment. The measurement should be easy and rapid to be more widely used in practice, which could be achieved by improvement of the user interface. In addition to prediction of recanalization, sequential measurements of thrombus volume before and after the treatment may also be useful to determine the efficacy of new thrombolytic drugs. This manuscript reviews the diagnosis of thrombus, prediction of recanalization using thrombus imaging, and practical considerations for the measurement of thrombus burden and density on CT.