Correlation of Thrombectomy Maneuver Count with Recanalization Success and Clinical Outcome in Patients with Ischemic Stroke

Clinical Study of Symptomatic Nonacute Intracranial Large Arterial Occlusion with Endovascular Recanalization

Objectives  This study reported a single-center clinical trial of endovascular treatment for symptomatic nonacute occlusion of the intracranial large artery (NA-ILAO). The aim of this study was to evaluate the safety, feasibility, and clinical effect of simple balloon dilatation and stent implantation. Methods  The patients diagnosed with symptomatic NA-ILAO were enrolled. A total of 40 cases were included in this study. While recanalization failed in 4 patients, it was successful in 36 patients, who were then divided into two groups for further analysis: balloon dilatation group ( n  = 24) and stent implantation group ( n  = 12). The perioperative complications, clinical outcome, and follow-up results were analyzed. Results  Perioperative complications in the stent implantation group were significantly higher than those in the simple balloon dilatation group ( p  < 0.05). There were 21 and 10 cases of 90-day good clinical outcome (modified Rankin scale [mRS] ≤ 2) in the balloon and stent groups, respectively ( p  = 0.518). All patients with successful recanalization underwent digital subtraction angiography (DSA) or CT angiography (CTA) during an average follow-up of 14 months. There were two cases of restenosis in the balloon dilatation group and one in the stent implantation group ( p  = 1.000). There were two cases of re-occlusion in the stent group and none in the balloon dilatation group ( p  < 0.001). Stroke recurred in two cases in the stent group and in one case in the simple balloon dilatation group ( p  = 0.013). Conclusion  Endovascular recanalization is safe and feasible for patients with symptomatic NA-ILAO. Compared with stent implantation, simple balloon dilation may be a better recanalization method, but larger randomized controlled trials are needed to confirm it.

After early mTICI 2b, stop or continue? Insights from the PERSIST Registry

OBJECTIVES

A higher reperfusion grade after endovascular thrombectomy (EVT) is associated with a good prognosis. However, the effect of the number of retrievals has not yet been investigated in vertebrobasilar occlusion (VBAO). Therefore, the aim of this study was to investigate whether to continue retrieval after early modified thrombolysis in cerebral infarction (mTICI) 2b to achieve a better reperfusion grade.

METHODS

We retrospectively analyzed the data of patients who underwent EVT caused by VBAO in a multicenter registry dataset. Patients who underwent successful reperfusion were included (mTICI 2b/3). Regression models were used to analyze the correlation of different reperfusion grades stratified by the number of retrieval attempts with clinical prognosis and hemorrhage transition.

RESULTS

We included 432 patients: 34.5% (n = 149) had a final mTICI score of 2b and 65.5% (n = 283) had a final mTICI score of 3. Patients who obtained a mTICI of 3 after the first pass had significantly increased odds of having a good prognosis. As the number of passes increases, the chances of obtaining a good prognosis decreases. After three or more passes, the odds of achieving functional independence and favorable outcomes were comparable to those of the first mTICI 2b, regardless of the 90-day (OR 1.132 95% CI 0.367-3.487 p = 0.829; OR 1.070 95% CI 0.375-3.047 p = 0.900) or 1-year follow-up (OR 1.217 95% CI 0.407-3.637 p = 0.725; OR 1.068 95% CI 0.359-3.173 p = 0.906).

INTERPRETATION

Within two retrieval attempts, mTICI 3 was better than the first retrieval to mTICI 2b. After early mTICI 2b, each retrieval should be undertaken with caution to pursue a higher reperfusion grade.

Number of passes and outcome of endovascular treatment of anterior circulation large core ischemic stroke: insights from the Endovascular Treatment in Ischemic Stroke (ETIS) registry

BACKGROUND

The effect of multiple attempts on the outcome of endovascular treatment (EVT) of anterior circulation large ischemic core (LIC) stroke has not been fully explored.

METHODS

We analyzed data from the Endovascular Treatment in Ischemic Stroke (ETIS) registry, a prospective, observational, multicenter study of acute ischemic stroke patients treated with EVT at 21 centers in France between January 1, 2015 and June 31, 2023. We included patients with proximal intracranial occlusion and LIC defined as Alberta Stroke Program Early CT Score (ASPECTS) of 0-5 up to 24 hours after last being seen well. We divided patients according to the number of passes with successful reperfusion (modified Thrombolysis In Cerebral Infarction (mTICI) ≥2b) into seven groups, according to the corresponding number of passes. We compared them to the group of patients with unsuccessful reperfusion.

RESULTS

A total of 1235 patients with LIC constituted the study cohort. The rate of a modified Rankin Scale (mRS) score of 0 to 3 at 90 days was significantly higher for the one-pass successful recanalization category compared to no recanalization (48.1% vs 17.2%; adjusted OR (aOR) 7.99, 95% CI 4.30 to 14.8, P<0.001) and remained so even after six or more attempts (27.7% vs 17.2%; aOR 3.59, 95% CI 1.37 to 9.39, P=0.009). The rate of symptomatic intracranial hemorrhage was lower for successful recanalization up to two passes (11.1% vs 18.8%; aOR 0.36, 95% CI 0.18 to 0.69, P=0.002) without any significant differences for a higher number of passes.

CONCLUSION

In anterior circulation LIC patients, successful reperfusion, even after six passes, is associated with favorable clinical outcomes with no increased hemorrhagic risk when compared to unsuccessful reperfusion.

A dynamic nomogram for predict individual risk of malignant brain edema after endovascular thrombectomy in acute ischemic stroke

The aim of this study was to develop a dynamic nomogram combining clinical and imaging data to predict malignant brain edema (MBE) after endovascular thrombectomy (EVT) in patients with large vessel occlusion stroke (LVOS). We analyzed the data of LVOS patients receiving EVT at our center from October 2018 to February 2023, and divided a 7:3 ratio into the training cohort and internal validation cohort, and we also prospectively collected patients from another stroke center for external validation. MBE was defined as a midline shift or pineal gland shift > 5 mm, as determined by computed tomography (CT) scans obtained within 7 days after EVT. A nomogram was constructed using logistic regression analysis, and its receiver operating characteristic curve (ROC) and calibration were assessed in three cohorts. A total of 432 patients were enrolled in this study, with 247 in the training cohort, 100 in the internal validation cohort, and 85 in the external validation cohort. MBE occurred in 24% (59) in the training cohort, 16% (16) in the internal validation cohort and 14% (12) in the external validation cohort. After adjusting for various confounding factors, we constructed a nomogram including the clot burden score (CBS), baseline neutrophil count, core infarct volume on CTP before EVT, collateral index, and the number of retrieval attempts. The AUCs of the training cohorts were 0.891 (95% CI 0.840-0.942), the Hosmer-Lemeshow test showed good calibration of the nomogram (P = 0.879). And our nomogram performed well in both internal and external validation data. Our nomogram demonstrates promising potential in identifying patients at elevated risk of MBE following EVT for LVOS.

Impact of Procedure Time on First Pass Effect in Mechanical Thrombectomy for Anterior Circulation Acute Ischemic Stroke

BACKGROUND AND OBJECTIVES

First pass effect (FPE) is a metric increasingly used to determine the success of mechanical thrombectomy (MT) procedures. However, few studies have investigated whether the duration of the procedure can modify the clinical benefit of FPE. We sought to determine whether FPE after MT for anterior circulation large vessel occlusion acute ischemic stroke is modified by procedural time (PT).

METHODS

A multicenter, international data set was retrospectively analyzed for anterior circulation large vessel occlusion acute ischemic stroke treated by MT who achieved excellent reperfusion (thrombolysis in cerebral infarction 2c/3). The primary outcome was good functional outcome defined by 90-day modified Rankin scale scores of 0-2. The primary study exposure was first pass success (FPS, 1 pass vs ≥2 passes) and the secondary exposure was PT. We fit-adjusted logistic regression models and used marginal effects to assess the interaction between PT (≤30 vs >30 minutes) and FPS, adjusting for potential confounders including time from stroke presentation.

RESULTS

A total of 1310 patients had excellent reperfusion. These patients were divided into 2 cohorts based on PT: ≤30 minutes (777 patients, 59.3%) and >30 minutes (533 patients, 40.7%). Good functional outcome was observed in 658 patients (50.2%). The interaction term between FPS and PT was significant ( P = .018). Individuals with FPS in ≤30 minutes had 11.5% higher adjusted predicted probability of good outcome compared with those who required ≥2 passes (58.2% vs 46.7%, P = .001). However, there was no significant difference in the adjusted predicted probability of good outcome in individuals with PT >30 minutes. This relationship appeared identical in models with PT treated as a continuous variable.

CONCLUSION

FPE is modified by PT, with the added clinical benefit lost in longer procedures greater than 30 minutes. A comprehensive metric for MT procedures, namely, FPE 30 , may better represent the ideal of fast, complete reperfusion with a single pass of a thrombectomy device.

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

Background and purpose

Mechanical thrombectomy is the standard treatment modality for flow restoration in acute ischemic stroke. In cases of persistent occlusion, the optimal number of retrieval attempts before considering procedure termination is currently undetermined and is a topic for research. Therefore in this study, we studied the impact of the number of stent retrieval maneuvers on the recanalization of vessels.

Methods

In this retrospective single-center observational study we included 52 patients with large vessel occlusion who underwent stent retriever mechanical thrombectomy. Successful recanalization rate was defined as modified TICI (Thrombolysis in Cerebral Infarction) 2b or 3.

Result

The overall successful recanalization rate was 44.24%. The recanalization rate per stent retrieval attempt was the highest in 1st attempt (28.84%) and no recanalization was observed with the 3rd, 5th, and 6th attempts (p<0.001). At most 6 retrieval attempts were used.

Conclusions

After two retrieval attempts, 91% of the patients were successfully recanalized and other after the 5th attempt could not result in recanalization.

Mechanical thrombectomy using the retrograde semi-retrieval technique for patients with underlying intracranial atherosclerotic stenosis

Background

The retrograde semi-retrieval technique (RESET) has been described as a modified technique for endovascular thrombectomy (EVT) whose safety and efficacy for intracranial atherosclerosis stenosis (ICAS) patients remain uncertain. This article presents our single-center experience, comparing RESET vs. non-RESET in ICAS patients.

Materials and methods

We analyzed 327 consecutive ICAS patients who underwent EVT at Tianjin Huanhu Hospital from January 2018 and December 2022. Patients were categorized into two groups: RESET and non-RESET. The primary outcome was the first-pass effect (FPE). Secondary outcomes included successful reperfusion, functional independence at 90 days, mortality, and symptomatic intracranial hemorrhage (sICH).

Results

RESET was significantly associated with FPE [adjusted odds ratio (aOR) 2.00, 95% confidence interval (CI) 1.03-3.87, p = 0.040]. RESET was not significantly associated with successful reperfusion (aOR 1.5, CI 0.55-4.06, p = 0.425), an mRS of 0-2 at 90 days (aOR 1.36, CI 0.83-2.21, p = 0.223), sICH (aOR 0.39, CI 0.12-1.23, p = 0.108), and mortality (aOR 0.49, CI 0.16-1.44, p = 0.193). After propensity score matching, the results were consistent with the primary analysis.

Conclusion

Compared to non-RESET, patients treated with RESET showed increased FPE incidence and significantly decreased puncture-to-reperfusion time. RESET was proven to be safe and effective in enhancing reperfusion for LVO patients receiving EVT with underlying ICAS.

Predictive Factors of First-Pass Effect in Patients Who Underwent Successful Endovascular Thrombectomy for Emergent Large Vessel Occlusion

OBJECTIVE

The primary treatment goal of current endovascular thrombectomy (EVT) for emergent large-vessel occlusion (ELVO) is complete recanalization after a single maneuver, referred to as the 'first-pass effect' (FPE). Hence, we aimed to identify the predictive factors of FPE and assess its effect on clinical outcomes in patients with ELVO of the anterior circulation.

METHODS

Among the 129 patients who participated, 110 eligible patients with proximal ELVO (intracranial internal carotid artery and proximal middle cerebral artery) who achieved successful recanalization after EVT were retrospectively reviewed. A comparative analysis between patients who achieved FPE and all others (defined as a non-FPE group) was performed regarding baseline characteristics, clinical variables, and clinical outcomes. Multivariate logistic regression analyses were subsequently conducted for potential predictive factors with p<0.10 in the univariate analysis to determine the independent predictive factors of FPE.

RESULTS

FPE was achieved in 31 of the 110 patients (28.2%). The FPE group had a significantly higher level of functional independence at 90 days than did the non-FPE group (80.6% vs. 50.6%, p=0.002). Pretreatment intravenous thrombolysis (IVT) (odds ratio [OR], 3.179; 95% confidence interval [CI], 1.025-9.861; p=0.045), door-to-puncture (DTP) interval (OR, 0.959; 95% CI, 0.932-0.987; p=0.004), and the use of balloon guiding catheter (BGC) (OR, 3.591; 95% CI, 1.231-10.469; p=0.019) were independent predictive factors of FPE.

CONCLUSION

In conclusion, pretreatment IVT, use of BGC, and a shorter DTP interval were positively associated with FPE, increasing the chance of acquiring better clinical outcomes.

The risk and outcome of malignant brain edema in post-mechanical thrombectomy: acute ischemic stroke by anterior circulation occlusion

BACKGROUND AND PURPOSE

Malignant brain edema (MBE) occurring after mechanical thrombectomy (MT) in acute ischemic stroke (AIS) could lead to severe disability and mortality. We aimed to investigate the incidence, predictors, and clinical outcomes of MBE in patients with AIS after MT.

METHODS

The clinical and imaging data of 155 patients with AIS of anterior circulation after MT were studied. Standard non-contrast CT was used to evaluate baseline imaging characteristics at admission. Clinical outcomes were measured using the 90-day modified Rankin Scale (mRS) score. Based on the follow-up CT scans performed within 72 h after MT, the patients were classified into MBE and non-MBE group. MBE was defined as a midline shift of ≥ 5 mm with signs of local brain swelling. Univariate and multivariate regression analyses were used to analyze the relationship between MBE and clinical outcomes and identify the predictors that correlate with MBE.

RESULTS

MBE was observed in 19.4% of the patients who underwent MT and was associated with a lower rate of favorable 90-day clinical outcomes. Significant differences were observed in both MBE and non-MBE groups: baseline Alberta Stroke Program Early CT (ASPECT) score, hyperdense middle cerebral artery sign (HMCAS), baseline signs of early infarct, angiographic favorable collaterals, number of retrieval attempts, and revascularization rate. Multivariate analysis indicated that low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count, and poor revascularization independently influenced the occurrence of MBE in AIS patients with anterior circulation after MT.

CONCLUSION

MBE was associated with a lower rate of favorable 90-day clinical outcomes. Low baseline ASPECT score, absent HMCAS, angiographic poor collaterals, more retrieval attempt count and poor revascularization were independently associated with MBE after MT.

Association Between Recanalization Attempts and Functional Outcome After Thrombectomy for Large Ischemic Stroke

BACKGROUND

Recently, 3 randomized controlled trials provided high-level evidence that patients with large ischemic stroke achieved better functional outcomes after endovascular therapy than with medical care alone. We aimed to investigate whether the clinical benefit of endovascular therapy is associated with the number of recanalization attempts in extensive baseline infarction.

METHODS

This retrospective multicenter study enrolled patients from the German Stroke Registry who underwent endovascular therapy for anterior circulation large vessel occlusion between 2015 and 2021. Large ischemic stroke was defined as an Alberta Stroke Program Early Computed Tomography Score of 3 to 5. The study cohort was divided into patients with unsuccessful reperfusion (Thrombolysis in Cerebral Infarction score, 0-2a) and successful reperfusion (Thrombolysis in Cerebral Infarction score, 2b/3) at attempts 1, 2, 3, or ≥4. The primary outcome was favorable functional outcome defined as modified Rankin Scale score of 0 to 3 at 90 days. Safety outcomes were symptomatic intracranial hemorrhage after 24 hours and death within 90 days. Multivariable logistic regression was used to identify independent determinants of primary and secondary outcomes.

RESULTS

A total of 348 patients met the inclusion criteria. Successful reperfusion was observed in 83.3% and favorable functional outcomes in 36.2%. Successful reperfusion at attempts 1 (adjusted odds ratio, 5.97 [95% CI, 1.71-24.43]; P=0.008) and 2 (adjusted odds ratio, 6.32 [95% CI, 1.73-26.92]; P=0.008) increased the odds of favorable functional outcome, whereas success at attempts 3 or ≥4 did not. Patients with >2 attempts showed higher rates of symptomatic intracranial hemorrhage (12.8% versus 6.5%; P=0.046). Successful reperfusion at any attempt lowered the odds of death compared with unsuccessful reperfusion.

CONCLUSIONS

In patients with large vessel occlusion and Alberta Stroke Program Early Computed Tomography Score of 3 to 5, the clinical benefit of endovascular therapy was linked to the number of recanalization attempts required for successful reperfusion. Our findings encourage to perform at least 2 recanalization attempts to seek for successful reperfusion in large ischemic strokes, while >2 attempts should follow a careful risk-benefit assessment in these highly affected patients.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03356392.

Prediction of delayed reperfusion in patients with incomplete reperfusion following thrombectomy

BACKGROUND

The clinical course of patients with incomplete reperfusion after thrombectomy, defined as an expanded Thrombolysis in Cerebral Infarction (eTICI) score of 2a-2c, is heterogeneous. Patients showing delayed reperfusion (DR) have good clinical outcomes, almost comparable to patients with ad-hoc TICI3 reperfusion. We aimed to develop and internally validate a model that predicts DR occurrence in order to inform physicians about the likelihood of a benign natural disease progression.

PATIENTS AND METHODS

Single-center registry analysis including all consecutive, study-eligible patients admitted between 02/2015 and 12/2021. Preliminary variable selection for the prediction of DR was performed using bootstrapped stepwise backward logistic regression. Interval validation was performed with bootstrapping and the final model was developed using a random forests classification algorithm. Model performance metrics are reported with discrimination, calibration, and clinical decision curves. Primary outcome was concordance statistics as a measure of goodness of fit for the occurrence of DR.

RESULTS

A total of 477 patients (48.8% female, mean age 74 years) were included, of whom 279 (58.5%) showed DR on 24 follow-up. The model's discriminative ability for predicting DR was adequate (C-statistics 0.79 [95% CI: 0.72-0.85]). Variables with strongest association with DR were: atrial fibrillation (aOR 2.06 [95% CI: 1.23-3.49]), Intervention-To-Follow-Up time (aOR 1.06 [95% CI: 1.03-1.10]), eTICI score (aOR 3.49 [95% CI: 2.64-4.73]), and collateral status (aOR 1.33 [95% CI: 1.06-1.68]). At a risk threshold of R = 30%, use of the prediction model could potentially reduce the number of additional attempts in one out of four patients who will have spontaneous DR, without missing any patients who do not show spontaneous DR on follow-up.

CONCLUSIONS

The model presented here shows fair predictive accuracy for estimating chances of DR after incomplete thrombectomy. This may inform treating physicians on the chances of a favorable natural disease progression if no further reperfusion attempts are made.

NIMBUS geometric clot extractor for challenging clots: Real-world clinical experience and clot composition

PURPOSE

Revascularization rates following mechanical thrombectomy (MT) for acute ischemic stroke (AIS) remain suboptimal for patients with fibrin-rich, recalcitrant clots. The NIMBUS Geometric Clot Extractor has demonstrated promising in vitro revascularization rates using fibrin-rich clot analogs. This study assessed the retrieval rate and composition of clot using NIMBUS in a clinical setting.

METHODS

This retrospective study included patients who underwent MT with NIMBUS at two high-volume stroke centers between December 2019 and May 2021. NIMBUS was used for clots deemed challenging to remove at the interventionalist's discretion. At one of the centers, per pass clot was collected for histological analysis by an independent lab.

RESULTS

A total of 37 patients (mean age 76.87 ± 11.73 years; 18 female; mean time from stroke onset 11.70 ± 6.41 h) were included. NIMBUS was used as first and second-line device in 5 and 32 patients, respectively. The main reason for using NIMBUS (32/37) was the failure of standard MT techniques after a mean 2.86 ± 1.48 number of passes. Substantial reperfusion (mTICI ≥2b) was achieved in 29/37 patients (78.4%) with a mean of 1.81 ± 1.00 NIMBUS passes (mean 4.68 ± 1.68 passes with all devices), and NIMBUS was the final device used in 79.3% (23/29) of those cases. Clot specimens from 18 cases underwent composition analysis. Fibrin and platelets represented 31.4 ± 13.7% and 28.8 ± 18.8% of clot components; 34.4 ± 19.5% were red blood cells.

CONCLUSIONS

In this series, NIMBUS was effective in removing tough clots rich in fibrin and platelets in challenging real-world situations.

Successful reperfusion in relation to the number of passes: comparing outcomes of first pass expanded Treatment In Cerebral Ischemia (eTICI) 2B with multiple-pass eTICI 3

BACKGROUND

Higher expanded Treatment In Cerebral Ischemia (eTICI) reperfusion scores after endovascular treatment (EVT) are associated with better outcomes. However, the influence of the number of passes on this association is unclear. We aimed to compare outcomes of single-pass good reperfusion (eTICI 2B) with multiple-pass excellent/complete reperfusion (eTICI 2C/3) in daily clinical practice.

METHODS

We compared outcomes of patients in the MR CLEAN Registry with good reperfusion (eTICI 2B) in a single pass to those with excellent/complete reperfusion (eTICI 2C/3) in multiple passes. Regression models were used to investigate the association of single-pass eTICI 2B versus multiple-pass eTICI 2C/3 reperfusion with 90-day functional outcome (modified Rankin Scale (mRS)), functional independence (mRS 0-2), per-procedural complications and safety outcomes.

RESULTS

We included 699 patients: 178 patients with single-pass eTICI 2B, and 242 and 279 patients with eTICI 2C/3 after 2 and ≥3 passes, respectively. Patients with eTICI 2C/3 after 2 or ≥3 passes did not achieve significantly better functional outcomes compared with patients with single-pass eTICI 2B (adjusted common OR (acOR) 1.06, 95% CI 0.75 to 1.50 and acOR 0.88, 95% CI 0.74 to 1.05 for 90-day mRS, and adjusted OR (aOR) 1.24, 95% CI 0.78 to 1.97 and aOR 0.79, 95% CI 0.52 to 1.22 for functional independence).

CONCLUSIONS

Our results did not show better outcomes for patients who achieved eTICI 2C/3 in multiple, that is, two or more, passes when compared with patients with single-pass eTICI 2B. However, this concerns observational data. Further research is necessary to investigate the per-pass effect in relation to reperfusion and functional outcome.

Predictors of first-pass reperfusion for mechanical thrombectomy in acute ischemic stroke

BACKGROUND AND OBJECTIVE

Rapid reperfusion of ischemic penumbra in patients with acute stroke is critical to neurological recovery. Achieving reperfusion after first-pass mechanical thrombectomy has been associated with improved patient outcomes. However, the predictors for obtaining first-pass reperfusion are not well known.

METHODS

A single-institution retrospective study of all patients who underwent mechanical thrombectomy at a tertiary care center from January 2010 until March 2019 was conducted to assess for predictors of first-pass reperfusion.

RESULTS

A total of 257 patients were reviewed. Successful reperfusion was obtained in 63.4% of patients, and in 38% of patients on the first pass. On multivariate analysis, increasing door-to-puncture time was a negative predictor of FPR (OR 0.989, 95% CI = 0.980-0.997) and use of combined thrombectomy technique with stent-retriever and aspiration was a positive predictor of FPR compared to aspiration or stent-retriever alone (OR 4.441, 95% CI = 1.001-19.699).

CONCLUSIONS

Combination therapy using stent-retriever and aspiration may increase the chance of obtaining FPR, whereas delays in starting the procedure after patient arrival may decrease the odds of FPR. Rapid thrombectomy initiation and procedural technique may play in optimizing rates of FPR and ultimately patient outcomes, however, randomized controlled trials assessing these variables are necessary to determine optimal treatment strategies.

Prediction of midline shift after media ischemia using computed tomography perfusion

Background

Decision-making about the indication for decompressive hemicraniectomy in cases with malignant infarction in the territory of the middle cerebral artery (MCA) is still a matter of debate. Some scores have been introduced and tested, most of them are midline-shift dependent. We introduce the Kinematics of malignant MCA infarction (KM) index, which can be calculated based on an initial computed tomography perfusion scan and the chosen therapy (lysis/thrombectomy/conservative) in order to estimate the maximum midline-shift in the subsequent 6 days.

Methods

We retrospectively analyzed patients with middle cerebral artery infarction who had a non-enhanced computed tomography (CT) scan, CT angiography and a CT perfusion scan in the acute setting and who presented in our emergency room between 2015 and 2019. 186 patients were included. Midline shift was measured on follow-up imaging between days 0 and 6 after stroke. We evaluated Pearson’s correlation between the KM index and the amount of midline shift.

Results

The mean KM index of all patients was 1.01 ± 0.09 (decompressive hemicraniectomy subgroup 1.13 ± 0.13; midline shift subgroup 1.18 ± 0.13). The correlation coefficient between the KM index and substantial midline-shift was 0.61, p < 0.01 and between KM index and decompressive hemicraniectomy or death 0.47; p < 0.05. KM index > 1.02 shows a sensitivity of 92% (22/24) and a specificity of 78% (126/162) for detecting midline shifts. The area under curve of the receiver operator characteristics was 91% for midline shifts and 86% for the occurrence of decompressive hemicraniectomy or death.

Conclusion

In this retrospective study, KM index shows a strong correlation with significant midline-shift. The KM index can be used for risk classification regarding herniation and the need of decompressive hemicraniectomy.

Functional Aplasia of the Contralateral A1 Segment Influences Clinical Outcome in Patients with Occlusion of the Distal Internal Carotid Artery

Background: The importance of an A1 aplasia remains unclear in stroke patients. In this work, we analyze the impact of an A1 aplasia contralateral to an acute occlusion of the distal internal carotid artery (ICA) on clinical outcomes. Methods: We conducted a retrospective study of consecutive stroke patients treated with mechanical thrombectomy at 12 tertiary care centers between January 2015 and February 2021 due to an occlusion of the distal ICA. Functional A1 aplasia was defined as the absence of A1 or hypoplastic A1 (>50% reduction to the contralateral site). Functional independence was measured by the modified Rankin Scale (mRS ≤ 2). Results: In total, 81 out of 1068 (8%) patients had functional A1 aplasia contralateral to distal ICA occlusion. Patients with functional contralateral A1 aplasia were more severely affected on admission (median NIHSS 18, IQR 15−23 vs. 17, IQR 13−21; aOR: 0.672, 95% CI: 0.448−1.007, p = 0.054) and post-interventional ischemic damage was larger (median ASPECTS 5, IQR 1−7, vs. 6, IQR 3−8; aOR: 1.817, 95% CI: 1.184−2.789, p = 0.006). Infarction occurred more often within the ipsilateral ACA territory (20/76, 26% vs. 110/961, 11%; aOR: 2.482, 95% CI: 1.389−4.437, p = 0.002) and both ACA territories (8/76, 11% vs. 5/961, 1%; aOR: 17.968, 95% CI: 4.979−64.847, p ≤ 0.001). Functional contralateral A1 aplasia was associated with a lower rate of functional independence at discharge (6/81, 8% vs. 194/965, 20%; aOR: 2.579, 95% CI: 1.086−6.122, p = 0.032) and after 90 days (5/55, 9% vs. 170/723, 24%; aOR: 2.664, 95% CI: 1.031−6.883, p = 0.043). Conclusions: A functional A1 aplasia contralateral to a distal ICA occlusion is associated with a poorer clinical outcome.

The prognostic value of extracranial vascular characteristics on procedural duration and revascularization success in endovascularly treated acute ischemic stroke patients

Introduction

Vascular anatomy might affect endovascular treatment success in acute ischemic stroke patients with large vessel occlusion. We investigated the prognostic value of extracranial vascular characteristics on procedural time and revascularization success in patients with large vessel occlusion in the anterior cerebral circulation.

Patients and methods

We included 828 patients endovascularly treated within 6.5 hours of symptom onset from the Dutch MR CLEAN-Registry. We evaluated aortic arch configuration, stenosis and tortuosity of supra-aortic arteries, and internal carotid arteries (ICAs) on pre-intervention CTA. We constructed logistic prediction models for outcome variables procedural duration (≥60 minutes) and non-successful revascularization (extended thrombolysis in cerebral infarction (eTICI) of 0–2A) using baseline characteristics and assessed the effect of extracranial vascular characteristics on model performance.

Results

Cervical ICA tortuosity and stenosis ≥99% improved prediction of long procedural duration compared with baseline characteristics from area under the curve of 0.61 (95% CI: 0.57–0.65) to 0.66 (95% CI: 0.62–0.70) (P < 0.001). Cervical ICA tortuosity was significantly associated with non-successful recanalization. Prediction of non-successful revascularization did not improve after including aortic arch elongation, acute take-off angle, aortic variant, origin stenosis of supra-aortic arteries, and cervical ICA tortuosity, with an area under the curve of 0.63 (95% CI: 0.59–0.67) compared with 0.59 (95% CI: 0.55–0.63) (P = 0.11).

Conclusion

Extracranial vascular characteristics have additional prognostic value for procedural duration, but not for revascularization success, compared with baseline characteristics. Performance of both prediction models is limited in patients treated for large vessel occlusion.

Association of asymptomatic hemorrhage after endovascular stroke treatment with outcomes

BACKGROUND

Intracerebral hemorrhage (ICH) occurs in ~20%-30% of stroke patients undergoing endovascular therapy (EVT). However, there is conflicting evidence regarding the effect of asymptomatic ICH (aICH) on post-EVT outcomes. We sought to evaluate the effect of aICH on immediate and 90-day post-EVT neurological outcomes.

METHODS

In this post-hoc analysis of the multicenter, prospective Blood Pressure after Endovascular Therapy (BEST) study we identified subjects with ICH following EVT. This population was divided into no ICH, aICH, and symptomatic ICH (sICH). Associations with 90-day modified Rankin Scale (mRS) dichotomized by functional independence (0-2 vs 3-6) and early neurological recovery (ENR) were determined using univariate/multivariate logistic regression models.

RESULTS

Of 485 patients enrolled in BEST, 446 had 90-day follow-up data available. 92 (20.6%) developed aICH, and 18 (4%) developed sICH. Compared with those without ICH, aICH was not associated with worse 90-day outcome or lower ENR (OR 0.84 [0.53-1.35], P=0.55, aOR 0.84 [0.48-1.44], P=0.53 for 90-day mRS 0-2; OR 0.77 [0.48-1.23], P=0.34, aOR 0.72 [0.43-1.22] for ENR). aICH was not associated with 90-day outcome or ENR in patients with mTICI ≥2 b (OR 0.78 [0.48-1.26], P=0.33 for 90-day mRS 0-2; OR 0.89 [0.69-1.12], P=0.15 for ENR). A higher proportion of patients with aICH had mTICI ≥2 b than those without ICH (97%vs 87%, P=0.01).

CONCLUSIONS

aICH was not associated with worse outcomes in patients with large-vessel stroke treated with EVT. aICH was more frequent in patients with successful recanalization. Further validation of our findings in large cohort studies of EVT-treated patients is warranted.

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.

Studying Stroke Thrombus Composition After Thrombectomy: What Can We Learn?

The composition of ischemic stroke thrombi has gained an increasing amount of interest in recent years. The implementation of endovascular procedures in standard stroke care has granted researchers the unique opportunity to examine patient thrombus material. Increasing evidence indicates that stroke thrombi are complex and heterogenous, consisting of various biochemical (eg, fibrin, von Willebrand Factor, and neutrophil extracellular traps) and cellular (eg, red blood cells, platelets, leukocytes, and bacteria) components. This complex composition may explain therapeutic limitations and also offer novel insights in several aspects of stroke management. Better understanding of thrombus characteristics could, therefore, potentially lead to improvements in the management of patients with stroke. In this review, we provide a comprehensive overview of the lessons learned by examining stroke thrombus composition after endovascular thrombectomy and its potential relevance for thrombectomy success rates, thrombolysis, clinical outcomes, stroke etiology, and radiological imaging.

More Retrieval Attempts are Associated with Poorer Functional Outcome After Unsuccessful Thrombectomy

Purpose

In mechanical thrombectomy, it has been hypothesized that multiple retrieval attempts might the improve reperfusion rate but not the clinical outcome. In order to assess a potential harmful effect of a mechanical thrombectomy on patient outcome, the number of retrieval attempts was analyzed. Only patients with a thrombolysis in cerebral infarction (TICI) score of 0 were reviewed to exclude the impact of eventual successful reperfusion on the mechanical hazardousness of repeated retrievals.

Methods

In this study 6635 patients who underwent endovascular thrombectomy (EVT) for acute large vessel occlusion (LVO) from the prospectively administered multicenter German Stroke Registry were screened. Insufficient reperfusion was defined as no reperfusion (TICI score of 0), whereas a primary outcome was defined as functional independence (modified Rankin scale [mRS] 0–2 at day 90). Propensity score matching and multivariable logistic regressions were then performed to adjust for confounders.

Results

A total of 377 patients (7.8%) had a final TICI score of 0 and were included in the study. After propensity score matching functional independence was found to be significantly more frequent in patients who underwent ≤ 2 retrieval attempts (14%), compared to patients with > 2 retrieval attempts (3.9%, OR 0.29, 95% CI 0.07–0.73, p = 0.009). After adjusting for age, sex, admission NIHSS score, and location of occlusion, more than two retrieval attempts remained significantly associated with lower odds of functional independence at 90 days (OR 0.2, 95% CI 0.07–0.52, p = 0.002).

Conclusion

In patients with failure of reperfusion, more than two retrieval attempts were associated with a worse clinical outcome, therefore indicating a possible harmful effect of multiple retrieval attempts.

Supplementary Information

The online version of this article (10.1007/s00062-021-01054-w) contains supplementary material, which is available to authorized users.

Early TICI 2b or Late TICI 3-Is Perfect the Enemy of Good?

Background and Purpose

A Thrombolysis in Cerebral Infarction (TICI) score of 3 has been established as therapeutic goal in endovascular therapy (EVT) for acute ischemic stroke; however, in the case of early TICI2b reperfusion, the question remains whether to stop the procedure or to continue in the pursuit of perfection (i.e., TICI 2c/3).

Methods

A total of 6635 patients were screened from the German Stroke Registry. Patients who underwent EVT for occlusion of the middle cerebral artery (M1 segment), with final TICI score of 2b/3 were included. Multivariable logistic regression was performed with functional independence (modified Rankin Scale, mRS at day 90 of 0–2) as the dependent variable.

Results

Of 1497 patients, 586 (39.1%) met inclusion criteria with a final TICI score of 2b and 911 (60.9%) with a TICI score of 3. Patients who achieved first-pass TICI3 showed highest odds of functional independence (Odds ratio [OR] 1.71, 95% confidence interval [95% CI] 1.18–2.47). Patients who achieved TICI2b with the second pass (OR 0.53, 95% CI 0.31–0.89) or with three or more passes (OR 0.44, 95% CI 0.27–0.70) had significantly worse clinical outcomes compared to first-pass TICI2b. TICI3 at the second pass was by trend better than first-pass TICI2b (OR 1.55, 95% CI 0.98–2.45), but TICI3 after 3 or more passes (OR 0.93, 95% CI 0.57–1.50) was not significantly different from first-pass TICI2b.

Conclusion

First-pass TICI2b was superior to TICI2b after ≥ 2 retrievals and comparable to TICI3 at ≥ 3 retrievals. The potential benefit in outcome after achieving TICI3 following further retrieval attempts after first-pass TICI2b need to be weighed against the risks.

Supplementary Information

The online version of this article (10.1007/s00062-021-01048-8) contains supplementary material, which is available to authorized users.

Impact of Repeated Clot Retrieval Attempts on Infarct Growth and Outcome After Ischemic Stroke

OBJECTIVE

To determine whether the association between increasing number of clot retrieval attempts (CRA) and unfavorable outcome is due to an increase in emboli to new territory (ENT) and greater infarct growth (IG) in successfully recanalized patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO).

METHODS

Data were extracted from 2 pooled multicentric prospective registries of consecutive patients with anterior AIS-LVO treated with mechanical thrombectomy (MT) between January 2016 and 2019. Patients with pretreatment and 24-hour posttreatment diffusion-weighted imaging (DWI) achieving successful recanalization, defined as expanded Thrombolysis in Cerebral Infarction Scale score of 2B, 2C, or 3, were included. ENT were assessed and IG was measured by voxel-based segmentation after DWI coregistration. Associations between number of CRA, ENT, IG, and 3-month outcome were analyzed.

RESULTS

Four hundred nineteen patients achieving successful recanalization were included. ENT occurrence was strongly correlated with increasing CRA (ρ = 0.73, p = 10^-4). In multivariable linear analysis, IG was independently associated with CRA (β = 1.6 per retrieval attempt, 95% confidence interval [CI] 0.97-9.74, p = 0.03) and ENT (β = 2.7 [95% CI 1.21-4.1], p = 0.03). Unfavorable functional outcome (3-month modified Rankin Scale score >2) increased with each additional CRA. IG was an independent predictor of unfavorable outcome (odds ratio 1.05 [95% CI 1.02-1.07] per 1-mL IG increase, p = 10^-4) in binary logistic regression analysis.

CONCLUSIONS

Increasing number of CRA in acute stroke is correlated with an increased ENT rate and increased IG volume, affecting functional outcome even when successful recanalization is achieved.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that, for patients with acute stroke undergoing successful recanalization, an increasing number of CRA is associated with poorer functional outcome.

e-ASPECTS software improves interobserver agreement and accuracy of interpretation of aspects score

INTRODUCTION

There is increased interest in the use of artificial intelligence-based (AI) software packages in the evaluation of neuroimaging studies for acute ischemic stroke. We studied whether, compared to standard image interpretation without AI, Brainomix e-ASPECTS software improved interobserver agreement and accuracy in detecting ASPECTS regions affected in anterior circulation LVO.

METHODS

We included 60 consecutive patients with anterior circulation LVO who had TICI 3 revascularization within 60 minutes of their baseline CT. A total of 16 readers, including senior neuroradiologists, junior neuroradiologists and vascular neurologists participated. Readers interpreted CT scans on independent workstations and assessed final ASPECTS and evaluated whether each individual ASPECTS region was affected. Two months later, readers again evaluated the CT scans, but with assistance of e-ASPECTS software. We assessed interclass correlation coefficient for total ASPECTS and interobserver agreement with Fleiss' Kappa for each ASPECTS region with and without assistance of the e-ASPECTS. We also assessed accuracy for the readers with and without e-ASPECTS assistance. In our assessment of accuracy, ground truth was the 24 hour CT in this cohort of patients who had prompt and complete revascularization.

RESULTS

Interclass correlation coefficient for total ASPECTS without e-ASPECTS assistance was 0.395, indicating fair agreement compared, to 0.574 with e-ASPECTS assistance, indicating good agreement (P < 0.01). There was significant improvement in inter-rater agreement with e-ASPECTS assistance for each individual region with the exception of M6 and caudate. The e-ASPECTS software had higher accuracy than the overall cohort of readers (with and without e-ASPECTS assistance) for every region except the caudate.

CONCLUSIONS

Use of Brainomix e-ASPECTS software resulted in significant improvements in inter-rater agreement and accuracy of ASPECTS score evaluation in a large group of neuroradiologists and neurologists. e-ASPECTS software was more predictive of final infarct/ASPECTS than the overall group interpreting the CT scans with and without e-ASPECTS assistance.

Abnormal neurological pupil index is associated with malignant cerebral edema after mechanical thrombectomy in large vessel occlusion patients

BACKGROUND AND OBJECTIVES

Malignant cerebral edema (MCE) is a feared complication in patients suffering from large vessel occlusion. Variables associated with the development of MCE have not been clearly elucidated. Use of pupillometry and the neurological pupil index (NPi) as an objective measure in patients undergoing mechanical thrombectomy (MT) has not been explored. We aim to evaluate variables significantly associated with MCE in patients that undergo MT and hypothesize that abnormal NPi is associated with MCE in this population.

METHODS

A retrospective analysis of patients with acute ischemic stroke who had undergone MT at our institution between 2017 and 2020 was performed. Baseline and outcome variables were collected, including NPi values from pupillometry readings of patients within 72 h after the MT. Patients were divided into two groups: MCE versus non-MCE group. A univariate and multivariate analysis was performed.

RESULTS

Of 284 acute ischemic stroke patients, 64 (22.5%) developed MCE. Mean admission glucose (137 vs. 173; p < 0.0001), NIHSS on admission (17 vs. 24; p < 0.01), infarct core volume (27.9 vs. 17.9 mL; p = 0.0036), TICI score (p = 0.001), and number of passes (2.9 vs. 1.8; p < 0.0001) were significantly different between the groups. Pupillometry data was present for 64 patients (22.5%). Upon multivariate analysis, abnormal ipsilateral NPi (OR 21.80 95% CI 3.32-286.4; p = 0.007) and hemorrhagic conversion were independently associated with MCE.

CONCLUSION

Abnormal NPi and hemorrhagic conversion are significantly associated with MCE in patients following MT. Further investigation is warranted to better define an association between NPi and patient outcomes in this patient population.

Predictors for Failure of Early Neurological Improvement After Successful Thrombectomy in the Anterior Circulation

BACKGROUND AND PURPOSE

Failure of early neurological improvement (fENI) despite successful mechanical thrombectomy in the anterior circulation is a clinically frequent occurrence. Purpose of this analysis was to define independent clinical, radiological, laboratory, or procedural predictors for fENI.

METHODS

Retrospective single-center analysis of patients treated for acute ischemic stroke in the anterior circulation ensuing successful mechanical thrombectomy between January 2014 and April 2019. Patients were compared according to fENI (equal or higher National Institutes of Health Stroke Scale) and ENI (lower National Institutes of Health Stroke Scale at discharge). Thirty-eight variables were examined in multivariable analysis for association with fENI.

RESULTS

Five hundred forty-nine out of 1146 patients experienced successful recanalization (modified Treatment in Cerebral Ischemia 2c-3). fENI occurred in 115/549 (20.9%) patients. Independent predictors of fENI were premorbid modified Rankin Scale (odds ratio [OR] per point [IC], 1.21 [1.00-1.46], P=0.049), end-stage renal failure (OR [IC], 12.18 [2.01-73.63], P=0.007), admission glucose (OR [IC], 1.018 [1.004-1.013] per mg/dL, P=0.001), bridging IV lysis (OR [IC], 0.57 [0.35-0.93], P: 0.024), time from groin puncture to final recanalization (OR [IC], 1.004 [1.001-1.007] per minute, P=0.015), general anesthesia during mechanical thrombectomy (OR, 2.41 [1.43-4.08], P<0.001), symptomatic intracranial hemorrhage (OR [CI], 6.81 [1.84-25.16], P=0.004), and follow-up Alberta Stroke Program Early CT Score (OR [IC], 0.76 [0.69-0.84] per point, P<0.001). In a secondary analysis, involvement of the regions internal capsule, M4 and M5 (motor cortex) were further independent predictors for fENI. Patients with ENI were more likely to experience a good outcome (modified Rankin Scale on day 90, 0-2: n=229/435 [52.8%] versus n=13/115 [11.3%]; P<0.001).

CONCLUSIONS

The extent of infarction and the involvement of motor cortex and internal capsule as well as higher premorbid modified Rankin Scale, end-stage renal failure, high glucose level on admission, absence of bridging IV lysis, general anesthesia, and a longer therapy interval are presumably independent predictors for fENI in patients with successful mechanical thrombectomy.

Good Clinical Outcome Decreases With Number of Retrieval Attempts in Stroke Thrombectomy: Beyond the First-Pass Effect

Supplemental Digital Content is available in the text.

Background and Purpose:

Endovascular therapy is the standard of care in the treatment of acute ischemic stroke due to large-vessel occlusion. Often, more than one retrieval attempt is needed to achieve reperfusion. We aimed to quantify the influence of endovascular therapy on clinical outcome depending on the number of retrievals needed for successful reperfusion in a large multi-center cohort.

Methods:

For this observational cohort study, 2611 patients from the prospective German Stroke Registry included between June 2015 and April 2018 were analyzed. Patients who received endovascular therapy for acute anterior circulation stroke with known admission National Institutes of Health Stroke Scale score and Alberta Stroke Program Early CT Score, final Thrombolysis in Cerebral Infarction score, and number of retrievals were included. Successful reperfusion was defined as a Thrombolysis in Cerebral Infarction score of 2b or 3. The primary outcome was defined as functional independence (modified Rankin Scale score of 0–2) at day 90. Multivariate mixed-effects models were used to adjust for cluster effects of the participating centers and confounders.

Results:

The inclusion criteria were met by 1225 patients. The odds of good clinical outcome decreased with every retrieval attempt required for successful reperfusion: the first retrieval had the highest odds of good clinical outcome (adjusted odds ratio, 6.45 [95% CI, 4.0–10.4]), followed by the second attempt (adjusted odds ratio, 4.56 [95% CI, 2.7–7.7]), and finally the third (adjusted odds ratio, 3.16 [95% CI, 1.8–5.6]).

Conclusions:

Successful reperfusion within the first 3 retrieval attempts is associated with improved clinical outcome compared with patients without reperfusion. We conclude that at least 3 retrieval attempts should be performed in endovascular therapy of anterior circulation strokes.

Registration:

URL: https://www.clinicaltrials.gov. Unique identifier: NCT03356392.

Direct aspiration thrombectomy experience with the SOFIA 6F catheter in acute ischemic stroke

INTRODUCTION

As the SOFIA (Soft torqueable catheter Optimized For Intracranial Access) 6F catheter has a large luminal diameter, it can be used as an aspiration catheter. Furthermore, it may function as an intermediate catheter when a stent retriever is required.

PURPOSE

We aimed to evaluate the usefulness of the SOFIA 6F catheter in mechanical thrombectomy with the direct aspiration first pass technique.

METHOD

Patients who had undergone mechanical thrombectomy (September 2017-January 2019) using the SOFIA 6F catheter in two centers were retrospectively analyzed. We used the thrombolysis in cerebral infarction (TICI) scale to evaluate the success of recanalization. National Institutes of Health Stroke Scale scores on admission and discharge were used together with the modified Rankin Scale (mRS) scores at 90 days.

RESULTS

In 132 (89.1%) of the 148 cases, the thrombus was in the anterior system. The SOFIA 6F catheter reached the thrombus site in 130 (87.8%) cases. The rate of successful recanalization (TICI ≥ 2b) was 89.1%. The targeted clinical outcome (mRS score ≤ 2 at 90th days) was achieved in 49.3% of cases. Symptomatic intracranial hemorrhage occurred in 5.4%. The rate of emboli to new vascular territories was 5.4%. Mortality was 14.1%.

CONCLUSION

In the majority of our cases, the SOFIA 6F catheter provided effective and rapid recanalization with aspiration thrombectomy.

Systematic review and meta-analysis of current rates of first pass effect by thrombectomy technique and associations with clinical outcomes

BACKGROUND

First pass effect (FPE) in mechanical thrombectomy is thought to be associated with good clinical outcomes.

OBJECTIVE

To determine FPE rates as a function of thrombectomy technique and to compare clinical outcomes between patients with and without FPE.

METHODS

In July 2020, a literature search on FPE (defined as modified Thrombolysis in Cerebral Infarction (TICI) 2c-3 after a single pass) and modified FPE (mFPE, defined as TICI 2b-3 after a single pass) and mechanical thrombectomy for stroke was performed. Using a random-effects meta-analysis, we evaluated the following outcomes for both FPE and mFPE: overall rates, rates by thrombectomy technique, rates of good neurologic outcome (modified Rankin Scale score ≤2 at day 90), mortality, and symptomatic intracerebral hemorrhage (sICH) rate.

RESULTS

Sixty-seven studies comprising 16 870 patients were included. Overall rates of FPE and mFPE were 28% and 45%, respectively. Thrombectomy techniques shared similar FPE (p=0.17) and mFPE (p=0.20) rates. Higher odds of good neurologic outcome were found when we compared FPE with non-FPE (56% vs 41%, OR=1.78) and mFPE with non-mFPE (57% vs 44%, OR=1.73). FPE had a lower mortality rate (17% vs 25%, OR=0.62) than non-FPE. FPE and mFPE were not associated with lower sICH rate compared with non-FPE and non-mFPE (4% vs 18%, OR=0.41 for FPE; 5% vs 7%, OR=0.98 for mFPE).

CONCLUSIONS

Our findings suggest that approximately one-third of patients achieve FPE and around half of patients achieve mFPE, with equivalent results throughout thrombectomy techniques. FPE and mFPE are associated with better clinical outcomes.

Acute ischemic stroke endovascular therapy

Endovascular therapy (EVT) has become the standard treatment for large-vessel occlusion (LVO) acute ischemic stroke (AIS). EVT is now indicated in patients up to 24h from their last known well, provided that the patient meets specific clinical and imaging criteria. Improvements in thrombectomy devices, techniques, and operator experience have allowed successful EVT of ICA terminus, M1-MCA occlusions as well as proximal M2-MCA, basilar artery occlusions, and revascularization of tandem lesions. Mechanical thrombectomy failures still occur due to several factors, however, highlighting the need for further device and technical improvements. An ongoing debate exists regarding the need for pre-EVT thrombolytic agents, thrombectomy techniques, distal occlusions, anesthesia methods, the role of advanced neuroimaging, the treatment of patients with larger infarct core, and those presenting with milder stroke symptoms. Many of these questions are the subject of current or upcoming clinical trials. This review aims to provide an outline and discussion about the established recommendations and emerging topics regarding EVT for LVO AIS.

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.

Benefit of first-pass complete reperfusion in thrombectomy is mediated by limited infarct growth

BACKGROUND AND PURPOSE

The number of clot retrieval attempts required to achieve complete reperfusion by mechanical thrombectomy impacts functional outcome in acute ischaemic stroke (AIS). Complete reperfusion [expanded Treatment In Cerebral Infarction (eTICI) score = 3] at first pass (FP), is associated with the highest rates of favorable outcome compared to complete reperfusion by multiple passes. The aim of the present study was to investigate the relationship between FP complete reperfusion and infarct growth (IG).

METHODS

Anterior AIS patients with baseline and 24-h diffusion-weighted magnetic resonance imaging were included from two prospective registries. IG was measured by voxel-based segmentation of initial and 24-h diffusion-weighted imaging lesions. IG and favorable 3-month modified Rankin Scale (mRS) score (≤ 2) were compared between patients in whom complete reperfusion (eTICI 3) was achieved with a single pass (FP group) and those for whom multiple passes were required (MP group), after matching for confounding factors. Mediation analysis was performed to examine the association between FP and 3-month mRS score, with IG as mediating variable.

RESULTS

A total of 200 patients were included, of whom 118 (28.9%) had FP complete reperfusion. In case-control analysis, the FP group had lower IG than the MP group [8.7 (5.4-12.9) ml vs. 15.2 (11-22.6) ml, respectively; P = 0.03). Favorable outcome was higher in the FP population compared to a matched MP population (70.9% vs. 53.2%, respectively; P = 0.04). FP compete reperfusion (eTICI 3) was independently associated with favorable outcome in multivariable regression analysis [odds ratio 1.86, 95% confidence interval (CI) 1.01-4.39; P = 0.04]. The effect of complete reperfusion at FP on functional outcome was explained by limited IG in mediation analysis [indirect effect: -0.32 (95% CI -0.47 to -0.09)].

CONCLUSION

Complete reperfusion at FP is independently associated with significant decrease in IG compared to complete reperfusion by multiple attempts, explaining better functional outcomes.

Contrast Extravasation Post Thrombectomy in Patients With Acute Cerebral Stroke: A Review and Recommendations for Future Studies

Mechanical thrombectomy (MT) for cerebral revascularization in acute stroke is now considered standard of care in select patients. Patients are assessed routinely after MT with CT scanning. The phenomenon of contrast staining is well documented in the literature and is posited to be related to increased blood-brain barrier (BBB) permeability of susceptible and/or infarcting brain tissue allowing angiographic contrast to be visualized outside the normal cerebral vasculature. In some cases, this can progress to include frank blood/contrast extravasation or even more seriously lead to intraparenchymal hemorrhage (IPH) with less favorable clinical outcomes. The relationship of this staining phenomenon and how it may have a cause or effect relationship with progression to hemorrhage is unclear. Many studies have been performed trying to better characterize this radiographic finding in terms of accurate diagnosis and potential for influencing prognosis. A literature review included a glaring lack of standardization in the application of terminology and quantitative/qualitative analysis. Dual energy CT (DECT) appears to be the best imaging modality to differentiate blood from contrast, but its application is limited since it is not as available as conventional CT. The possibility that risk factors are associated with progression of mixed density (blood and contrast) extravasations to frank IPH with resultant poorer outcomes is suggested in some studies. Overall, there remains a lack of consensus on how to best interpret this radiographic finding in altering any future stroke treatment(s). Recommendations of how to overcome this are postulated by the authors, which include standardization of terminology, progression toward more DECT use.

Hyperattenuating lesions after mechanical thrombectomy in acute ischaemic stroke: factors predicting symptomatic haemorrhage and clinical outcomes

AIM

To evaluate the clinical significance of hyperattenuating lesions on CT after mechanical thrombectomy for acute ischaemic stroke, and to identify imaging factors that predict symptomatic haemorrhage and unfavourable outcomes.

MATERIALS AND METHODS

Seventy-eight patients with acute ischaemic stroke in the anterior circulation who underwent mechanical thrombectomy were evaluated. All patients underwent post-interventional unenhanced computed tomography (CT) within 24 h and follow-up CT or magnetic resonance imaging (MRI) within 7 days. Baseline characteristics and clinical outcomes were compared between patients with and without hyperattenuating lesions. In patients with hyperattenuating lesions, clinical and imaging factors that predict symptomatic haemorrhage and unfavourable outcomes were determined.

RESULTS

Fifty-six of 78 patients (71.8%) demonstrated hyperattenuating lesions on post-interventional CT. Patients with hyperattenuating lesions showed lower Alberta Stroke Program Early CT score (ASPECTS), persistent/symptomatic haemorrhage, and unfavourable outcomes than those without. In patients with hyperattenuating lesions, larger hyperattenuating lesion volume (>21.3 ml; OR, 55.60, p<0.001) and perilesional oedema (OR, 46.04, p=0.015) were independent factors predicting symptomatic haemorrhage. Older age (OR, 1.2, p=0.006) and lower ASPECTS (OR, 0.45, p=0.046) were independent factors predicting unfavourable outcomes in patients with hyperattenuating lesions. Adding the volume of the hyperattenuating lesion to age and ASPECTS increased the predictive performance of unfavourable outcomes (area under the curve 0.874 versus 0.934, p=0.043).

CONCLUSIONS

Hyperattenuating lesions on post-interventional CT are associated with increased risk of symptomatic haemorrhage and unfavourable outcomes. Larger hyperattenuating lesion volume is an independent factor of symptomatic haemorrhage and it has added predictive value for unfavourable outcomes.

Radiation exposure per thrombectomy attempt in modern endovascular stroke treatment in the anterior circulation

OBJECTIVE

To quantify radiation exposure (RE) of endovascular stroke treatment (EST) in the anterior circulation per thrombectomy attempt and determine causes for interventions associated with high RE.

METHODS

A retrospective single-center study of an institutional review board-approved stroke database of patients receiving EST for large vessel occlusions in the anterior circulation between January 2013 and April 2018 to evaluate reference levels (RL) per thrombectomy attempt. ESTs with RE above the RL were analyzed to determine causes for high RE.

RESULTS

Overall, n = 544 patients (occlusion location, M1 and M2 segments of the middle cerebral artery 53.5% and 27.2%, carotid artery 17.6%; successful recanalization rate 85.7%) were analyzed. In the overall population, DAP (in Gy cm2, median (IQR)) was 113.7 (68.9-181.7) with a median fluoroscopy time of 31 min (IQR, 17-53) and a median of 2 (IQR, 1-4) thrombectomy attempts. RE increased significantly with every thrombectomy attempt (DAP1, 68.7 (51.2-106.8); DAP2, 106.4 (84.8-115.6); p value1vs2, < 0.001; DAP3, 130.2 (89.1-183.6); p value2vs3, 0.044; DAP4, 169.9 (128.4-224.1); p value3vs4, 0.001; and DAP5, 227.6 (146.3-294.6); p value4vs5, 0.019). Procedures exceeding the 90th percentile of the attempt-dependent radiation exposure level were associated with procedural complications (n = 17/52, 29.8%) or a difficult vascular access (n = 8/52, 14%).

CONCLUSIONS

Radiation exposure in endovascular stroke treatment is depending on the number of thrombectomy attempts. Radiation exposure doubles when three attempts and triples when five attempts are necessary compared with single-maneuver interventions. Procedural complications and difficult vascular access were associated with a high radiation exposure in this collective.

KEY POINTS

• Radiation exposure of endovascular stroke treatment (EST) is dependent on the number of thrombectomy attempts. • Reference levels as means for quality control in hospitals performing endovascular stroke treatment should be defined by the number of thrombectomy attempts-we suggest 107 Gy cm2, 156 Gy cm2, 184 Gy cm2, 244 Gy cm2, and 295 Gy cm2 for 1 to 5 maneuvers, respectively, for EST of the anterior circulation • Cases with high rates of radiation exposure are associated with periprocedural complications and difficult anatomical access as a probable cause for a high radiation exposure.

Effect of treatment technique on radiation exposure in mechanical thrombectomy for acute ischaemic stroke: A matched-pair analysis

OBJECTIVE

This study aimed to compare radiation exposure (RE) in patients receiving mechanical thrombectomy (MT) for large-vessel occlusions in the anterior circulation using direct thrombo-aspiration (DT) versus stent-retriever thrombectomy under continuous distal aspiration (STA).

METHODS

This was a retrospective single-centre analysis of an Institutional Review Board-approved stroke database of a comprehensive stroke centre focusing on RE per dose area product, procedure time (PT) and fluoroscopy time (FT) in patients receiving MT. Patients who received MT with DT were matched with patients treated using STA according to occlusion location, mode of anaesthesia, manoeuvre count and sex.

RESULTS

Apart from patient age (DT: M = 74 years (standard deviation (SD)=13 years); STA: M = 79 years (SD = 11 years); p = 0.023), there was no difference in baseline patient characteristics (n = 68 per group). PT (DT: median = 26 minutes (interquartile range (IQR) = 21-38 minutes); STA: median = 49 minutes (IQR 37-77 minutes); p < 0.0001) and FT (DT: median = 12 minutes (IQR 7-18 minutes); STA: median = 26 minutes (IQR 14-43 minutes); p < 0.0001) were shorter in patients who received MT using DT. RE (DT: median = 62.6 Gy·cm² (IQR 41.7-89.4 Gy·cm²); STA: median = 89.8 Gy·cm² (IQR 53.7-131.7 Gy·cm²); p = 0.034) was significantly lower in patients who received MT using DT. This represents a relative increase of RE, FT and PT by 43.6%, 116.6% and 88.5%, respectively, in patients who received MT using STA.

CONCLUSION

MT using DT is associated with shorter FT and PT and lower RE compared to matched patients treated with STA.

Association of Time From Stroke Onset to Groin Puncture With Quality of Reperfusion After Mechanical Thrombectomy: A Meta-analysis of Individual Patient Data From 7 Randomized Clinical Trials

Importance

Reperfusion is a key factor for clinical outcome in patients with acute ischemic stroke (AIS) treated with endovascular thrombectomy (EVT) for large-vessel intracranial occlusion. However, data are scarce on the association between the time from onset and reperfusion results.

Objective

To analyze the rate of reperfusion after EVT started at different intervals after symptom onset in patients with AIS.

Design, Setting, and Participants

We conducted a meta-analysis of individual patient data from 7 randomized trials of the Highly Effective Reperfusion Using Multiple Endovascular Devices (HERMES) group. This is a multicenter cohort study of the intervention arm of randomized clinical trials included in the HERMES group. Patients with anterior circulation AIS who underwent EVT for M1/M2 or intracranial carotid artery occlusion were included. Each trial enrolled patients according to its specific inclusion and exclusion criteria. Data on patients eligible but not enrolled (eg, refusals or exclusions) were not available. All analyses were performed by the HERMES biostatistical core laboratory using the pooled database. Data were analyzed between December 2010 and April 2015.

Main Outcomes and Measures

Successful reperfusion was defined as a modified thrombolysis in cerebral infarction score of 2b/3 at the end of the EVT procedure adjusted for age, occlusion location, pretreatment intravenous thrombolysis, and clot burden score and was analyzed in relation to different intervals (onset, emergency department arrival, imaging, and puncture) using mixed-methods logistic regression.

Results

Among the 728 included patients, with a mean (SD) age of 65.4 (13.5) years and of whom 345 were female (47.4%), decreases in rates of successful reperfusion defined as a thrombolysis in cerebral infarction score of 2b/3 were observed with increasing time from admission or first imaging to groin puncture. The magnitude of effect was a 22% relative reduction (odds ratio, 0.78; 95% CI, 0.64-0.95) per additional hour between admission and puncture and a 26% relative reduction (odds ratio, 0.74; 95% CI, 0.59-0.93) per additional hour between imaging and puncture.

Conclusions and Relevance

Because the probability of reperfusion declined significantly with time between hospital arrival and groin puncture, we provide additional arguments for minimizing the intervals after symptom onset in anterior circulation acute ischemic stroke.

Recanalization Rate per Retrieval Attempt in Mechanical Thrombectomy for Acute Ischemic Stroke

Background and Purpose- In acute ischemic stroke, mechanical thrombectomy allows flow restoration in the majority of cases. In case of an unsuccessful retrieval, little is known about how many retrieval attempts should be performed before stopping the procedure. This study assessed the recanalization rate and clinical outcome per retrieval maneuver. Methods- In this analysis, 330 patients with acute large vessel occlusion treated exclusively with stentrieval devices were included. Successful recanalization was defined as Thrombolysis in Cerebral Infarction 2b-3, a good clinical outcome was defined as modified Rankin Scale at 90 days of ≤2. Results- The median number of retrieval attempts was 1 (interquartile range, 1-2, maximum 8). Recanalization rates per retrieval attempt were highest for the first retrieval (46.8%) and lowest for the fifth retrieval (22.7%). After 3 retrieval attempts, 67.9% of patients were successfully recanalized. Patients with 1 to 3 retrieval attempts had higher rates of good clinical outcome (28.9% versus 7.4%; P=0.018). The number of passes was an independent negative predictor of good clinical outcome (adjusted odds ratio, 0.65; 95% CI, 0.435-0.970; P=0.035). Conclusions- Two-thirds of occlusions were successfully recanalized with up to 3 retrieval attempts. Further attempts had good recanalization rates, but the rate of favorable clinical outcome did not improve.

When to Stop

Background and Purpose- Substantial proportion of patients who achieve successful recanalization of acute ischemic stroke due to large vessel occlusion do not achieve good functional outcome. We aim to analyze the effect of number of thrombectomy device passes and degree of the recanalization (by modified Thrombolysis in Cerebral Infarction) on the clinical and functional outcome. Methods- Five hundred forty-two consecutive patients underwent mechanical thrombectomy for large vessel occlusion in the anterior circulation at a single tertiary stroke center. Baseline characteristics, number of passes, recanalization degree, clinical outcome at 24 hours (measured by National Institutes of Health Scale score), and functional outcome (measured by modified Rankin Scale at 90 days) were registered. Multivariate analysis was performed to determine the association of number of passes and degree of recanalization with dramatical clinical recovery (final National Institutes of Health Scale score ≤2 or decrease in 8 or more National Institutes of Health Scale score points in 24 hours) and good functional outcome (modified Rankin Scale score ≤2 at 90 days). Results- Four hundred fifty-nine patients (84%) achieved successful recanalization (modified Thrombolysis in Cerebral Infarction 2B-3), 213 (39%) of them after first device pass. In the multivariate analysis, first-pass recanalization and modified Thrombolysis in Cerebral Infarction 3 were independent predictors of good functional outcome (odds ratio, 2.5; 95% CI, 1.4-4.5; P=0.002 and odds ratio, 2.6 CI; 1.5-4.7; P=0.001, respectively) and dramatical clinical recovery (odds ratio, 1.8; 95% CI, 1.1-3; P=0.032 and odds ratio, 2.9; 95% CI, 1.7-5.1; P<0.001, respectively). Rate of recanalization declined after each pass 39% (213/542), 35% (113/310), 33% (63/190), and 24% (26/154) for passes 1 to 4, respectively and 28% (45/158) for every attempt above 4 passes ( P<0.001). In patients who achieved recanalization, a linear association between number of passes and good functional outcome was observed: 1 pass (58.6%), 2 passes (50.5%), 3 passes (48.4%), 4 passes (38.5%), or 5 or more passes (25.6%; P<0.001) as compared with patients who did not achieve recanalization (16.9%). Conclusions- High number of device passes and less degree of recanalization are associated with worse outcome in patients with acute ischemic stroke secondary to large vessel occlusion. Future studies should investigate the optimal number of passes that should be attempted in patients without substantial recanalization.

Clot reduction prior to embolectomy: mSAVE as a first-line technique for large clots

Introduction

The “Stent retriever Assisted Vacuum-locked Extraction” (SAVE) technique is a promising embolectomy method for intracranial large vessel occlusion (LVO). We report our experience using a modified SAVE (mSAVE) approach for clot reduction prior to embolectomy in acute ischemic stroke patients with large clots.

Materials and methods

We retrospectively analyzed 20 consecutive patients undergoing mSAVE in our center due to intracranial LVO. Angiographic data (including first-pass and overall complete reperfusion, defined as an expanded Thrombolysis in Cerebral Infarction (eTICI) score of 3, rate of successful reperfusion (eTICI ≥2c), number of passes, time from groin puncture to reperfusion) and clinical data (favorable outcome at 90 days, defined as modified Rankin Scale (mRS) ≤2) were assessed.

Results

First-pass and overall eTICI 3 reperfusion was reached in 13/20 (65%) and 14/20 (70%), respectively. The rate of successful reperfusion (eTICI ≥2c) after one pass was 85% and on final angiogram 90% with an average number of 1.1 ± 0.3 attempts. Eight out of 11 (73%) ICA occlusions were reperfused successfully and 5 (46%) completely after a single pass. Median groin to reperfusion time was 33 minutes (IQR 25–46). A favorable clinical outcome was achieved in 9/20 (45%) patients at discharge and after 90 days, respectively.

Conclusion

Clot reduction followed by embolectomy (mSAVE) is feasible and may be an important tool in the treatment of large clots.

Beyond the first pass: revascularization remains critical in stroke thrombectomy

BACKGROUND

The first pass effect has been recently reported as a predictor of good clinical outcome after stroke thrombectomy. We evaluate the first pass effect on outcome and the influence of revascularization in these and other patients.

METHODS

We performed a retrospective analysis of a prospectively maintained database on anterior cerebral circulation stroke thrombectomy cases from April 2012 to April 2018. Data compiled included patient demographics, presenting National Institutes of Health Stroke Scale score, vessel occlusion site, thrombectomy procedural details, and 90 day modified Rankin Scale scores.

RESULTS

205 patients were included. The numbers of patients who underwent one, two, three, four, five, and six passes were 69, 70, 55, 9, 1, and 1, respectively. Successful revascularization was achieved in 87%, 83%, and 64% of patients in the one, two, and 3 or more passes groups, respectively (p=0.002). Good functional outcome was inversely correlated with number of passes when comparing the one, two, and three or more passes groups (54%, 43%, 29%; P=0.014). In patients with full revascularization, there was no significant difference in good functional outcomes between the one, two, and three or more passes groups (64%, 65%, 50%; P=0.432). Number of passes was not an independent negative predictor of good clinical outcome (OR 1.66, 95% CI 0.82 to 3.39; P=0.165).

CONCLUSIONS

First pass thrombectomy patients have better functional outcomes compared with beyond-first pass patients. This effect is related at least in part to a higher rate of revascularization in one pass patients. Revascularization beyond the first pass should continue to be the goal of stroke thrombectomy.

Risk factors of intracranial hemorrhage after mechanical thrombectomy of anterior circulation ischemic stroke

PURPOSE

Intracranial hemorrhage (ICH) is a potentially severe complication after mechanical thrombectomy (MT). Here, we investigated risk factors for the occurrence of any and symptomatic ICH after MT due to large-vessel occlusion of the anterior circulation.

METHODS

Consecutive patients with acute ischemic anterior circulation stroke with large-vessel occlusion undergoing MT were analyzed. ICH was categorized according to the Heidelberg Bleeding Classification. Forty-three procedural and clinical parameters were analyzed using univariate tests and multivariate logistic regressions.

RESULTS

Of 612 patients, any ICH was detected in 195 (31.9%), while 27 (4.4%) developed a symptomatic ICH. Infarct size > 1/3 of vascular territory in control imaging (OR 2.18, 95% CI 1.45-3.21), higher serum glucose levels (OR 1.23 for change of 15 units mg/dL, 95% CI 1.10-1.39), and higher thrombectomy maneuver count (OR 1.21, 95% CI 1.11-1.32) were significantly associated with a higher risk of developing any ICH compared to no ICH. Wake-up strokes (OR 3.99, 95% CI 1.38-11.60), transfer from an external clinic (OR 3.04, 95% CI 1.24-7.48), and higher serum glucose levels (OR 1.22 for change of 15 units mg/dL, 95% CI 1.05-1.42) were revealed as independent risk factors for development of symptomatic ICH compared to no symptomatic ICH. Patients with no infarct demarcation (OR 0.10, 95% CI 0.01-0.80) and complete recanalization (OR 0.57, 95% CI 0.37-0.86) showed a lower risk of developing any ICH.

CONCLUSION

Wake-up strokes and patients who are treated within a drip-and-ship concept are especially vulnerable for symptomatic ICH, while complete recanalization, contrary to subtotal recanalization only, was revealed as a protective factor against ICH.