Complete reperfusion mitigates influence of treatment time on outcomes after acute stroke

Reperfusion measurements, treatment time, and outcomes in patients receiving endovascular treatment within 24 hours of last known well

AIMS

The aim of this study was to explore the interaction between reperfusion and treatment time on the outcomes of patients undergoing endovascular treatment presenting within 24 h of last known well, and to compare the predictive ability of different reperfusion measurements on outcomes.

METHODS

Eligible patients from a single-center cohort were enrolled in this study. Reperfusion was assessed using reperfusion index (decreased volume of hypoperfusion lesion compared with baseline) measured by repeated perfusion imaging, and modified treatment in cerebral ischemia score measured by digital subtraction angiography, respectively. The interactions between reperfusion measurements and treatment time on outcomes were explored using multivariate-adjusted logistic and linear regression models. The predictive abilities of reperfusion measurements on outcomes were compared using area under the receiver operating characteristic curve (ROC-AUC) and values of R-square.

RESULTS

Reperfusion index and treatment time had significant interactions on 3-month modified Rankin Scale (mRS) 0-2 and infarct growth (p for interaction <0.05). Although the AUCs were statistically similar (AUCs of mRS 0-2 prediction, mTICI≥2b:0.63, mTICI≥2c:0.59, reperfusion index≥0.5:0.66, reperfusion index ≥0.9:0.73, P value of any of the two AUCs >0.05), reperfusion index≥0.9 showed the highest R-square values in outcome prediction (R-square values of 3-month mRS 0-2 and infarct growth = 0.21) among all the reperfusion measurements.

CONCLUSION

Treatment time mitigated the effect of reperfusion on outcomes of patients receiving endovascular treatment within 24 h of last known well. Reperfusion index≥0.9 might serve as a better proxy of good outcomes compared with other reperfusion measurements.

Predictors of Early Neurological Improvement in Patients with Anterior Large Vessel Occlusion and Successful Reperfusion Following Endovascular Thrombectomy-Does CT Perfusion Imaging Matter?

PURPOSE

We aimed to investigate treatment effect of endovascular thrombectomy (EVT) on the change of National Institutes of Health Stroke Scale (NIHSS) scores in acute ischemic stroke (AIS) patients with anterior large vessel occlusion (LVO). Predictors of early neurological improvement (ENI) were assessed in those with successful reperfusion.

METHODS

Data on stroke patients from January 2018 to December 2020 were retrospectively analyzed. Anterior LVO was defined as occlusion of internal carotid artery and/or M1/M2 branch of middle cerebral artery. A reduction of at least 8 NIHSS points at 24 h after EVT or NIHSS score ≤ 1 at discharge was defined as ENI. In patients with successful reperfusion (TICI score of 2b/3) and available CT perfusion (CTP) imaging, 20 variables were tested in a smoothed ridge regression for their association with ENI.

RESULTS

One hundred seventy two out of 211 patients had successful perfusion with 54 patients achieving ENI. Impact of successful EVT on reducing NIHSS score grew continuously on a daily basis up to the date of discharge. 105 out of 172 patients were included in final regression model. Short time from onset to admission and from groin-puncture to reperfusion, young age, low prestroke disability, high baseline CTP ASPECTS and high follow-up non-contrast CT (NCCT) ASPECTS were significantly associated with ENI. Neither baseline NCCT ASPECTS nor the volume of penumbra or ischemic core measured on CTP were associated with ENI.

CONCLUSION

CTP ASPECTS might better predict ENI than non-contrast CT at baseline in patients with successful reperfusion following EVT.

Benchmarking the Extent and Speed of Reperfusion: First Pass TICI 2c-3 Is a Preferred Endovascular Reperfusion Endpoint

Background and Purpose: End-of-procedure substantial reperfusion [modified Treatment in Cerebral Ischemia (mTICI) 2b-3], the leading endpoint for thrombectomy studies, has several limitations including a ceiling effect, with recent achieved rates of ~90%. We aimed to identify a more optimal definition of angiographic success along two dimensions: (1) the extent of tissue reperfusion, and (2) the speed of revascularization.

Methods: Core-lab adjudicated TICI scores for the first three passes of EmboTrap and the final all-procedures result were analyzed in the ARISE II multicenter study. The clinical impact of extent of reperfusion and speed of reperfusion (first-pass vs. later-pass) were evaluated. Clinical outcomes included 90-day functional independence [modified Rankin Scale (mRS) 0–2], 90-day freedom-from-disability (mRS 0–1), and dramatic early improvement [24-h National Institutes of Health Stroke Scale (NIHSS) improvement ≥ 8 points].

Results: Among 161 ARISE II subjects with ICA or MCA M1 occlusions, reperfusion results at procedure end showed substantial reperfusion in 149 (92.5%), excellent reperfusion in 121 (75.2%), and complete reperfusion in 79 (49.1%). Reperfusion rates on first pass were substantial in 81 (50.3%), excellent reperfusion in 62 (38.5%), and complete reperfusion in 44 (27.3%). First-pass excellent reperfusion (first-pass TICI 2c-3) had the greatest nominal predictive value for 90-day mRS 0–2 (sensitivity 58.5%, specificity 68.6%). There was a progressive worsening of outcomes with each additional pass required to achieve TICI 2c-3.

Conclusions: First-pass excellent reperfusion (TICI 2c-3), reflecting rapid achievement of extensive reperfusion, is the technical revascularization endpoint that best predicted functional independence in this international multicenter trial and is an attractive candidate for a lead angiographic endpoint for future trials.

Clinical Trial Registration:http://www.clinicaltrials.gov, identifier NCT02488915.

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.

Door-in-Door-Out Time at Primary Stroke Centers May Predict Outcome for Emergent Large Vessel Occlusion Patients

Background and Purpose—

Interfacility transfers for thrombectomy in stroke patients with emergent large vessel occlusion (ELVO) are associated with longer treatment times and worse outcomes. In this series, we examined the association between Primary Stroke Center (PSC) door-in to door-out (DIDO) times and outcomes for confirmed ELVO stroke transfers and factors that may modify the interaction.

Methods—

We retrospectively identified 160 patients transferred to a single Comprehensive Stroke Center (CSC) with anterior circulation ELVO between July 1, 2015 and May 30, 2017. We included patients with acute occlusions of the internal carotid artery or proximal middle cerebral artery (M1 or M2 segments), with a National Institutes of Health Stroke Scale score of ≥6. Workflow metrics included time from onset to recanalization, PSC DIDO, interfacility transfer time, CSC arrival to arterial puncture, and arterial puncture to recanalization. Primary outcome measure was National Institutes of Health Stroke Scale at discharge and modified Rankin Scale (mRS) score at 90 days.

Results—

The median (Q1–Q3) age and National Institutes of Health Stroke Scale of the 130 ELVO transfers analyzed was 75 (64–84) and 17 (11–22). Intravenous alteplase was administered to 64% of patients. Regarding specific workflow metrics, median (Q1–Q3) times (in minutes) were 241 (199–332) for onset to recanalization, 85 (68–111) for PSC DIDO, 26 (17–32) for interfacility transport, 21 (16–39) for CSC door to arterial puncture, and 24 (15–35) for puncture to recanalization. Median discharge National Institutes of Health Stroke Scale score was 5 (2–16), and 46 (35%) patients had a favorable outcome at 90 days. Complete reperfusion (modified Thrombolysis in Cerebral Ischemia 2c/3) modified the deleterious association of DIDO on outcome.

Conclusions—

For patients diagnosed with ELVO at a PSC who are being transferred to a CSC for thrombectomy, longer DIDO times may have a deleterious effect on outcomes and may represent the single biggest modifiable factor in onset to recanalization time. PSCs should make efforts to decrease DIDO and routine use of DIDO as a performance measure is encouraged.

Redefining 'success': a systematic review and meta-analysis comparing outcomes between incomplete and complete revascularization

BACKGROUND

Conventionally, 'successful' endovascular thrombectomy (EVT) had been defined as achieving revascularization of thrombolysis in cerebral infarction (TICI)-2B or greater, rather than as 'complete' (TICI-3) versus 'incomplete' (TICI-2B) revascularization.

PURPOSE

We performed a systematic review and meta-analysis of studies comparing clinical outcomes between patients with TICI-2B and TICI-3 revascularization.

METHODS

Multiple databases were searched for relevant publications between January 2003 and March 2018. Studies comparing outcomes between the TICI-2B and the TICI-3 group of acute ischemic stroke (AIS) patients treated with EVT were included. Random effects meta-analysis was performed to evaluate outcomes among TICI-2B and TICI-3 groups. The following outcomes were assessed: good neurologic outcome (modified Rankin Scale (mRS)≤2 at day 90), mortality, and intracerebral hemorrhage (ICH).

RESULTS

Twenty-one studies comprising 2747 patients were identified. Patients with TICI-2B revascularization had mRS≤2 at day 90 rates of 46% (391/847) compared with 66% (522/791) for TICI-3 patients (OR 0.46, 95% CI 0.37 to 0.57). Mortality rates were significantly higher in the TICI-2B group (78/570, 14%) than in the TICI-3 group (55/709, 8%) (OR 2.00, 95% CI 1.38 to 2.91). The ICH rates were also significantly higher in the TICI-2B group as compared with the TICI-3 group (31% [134/439] vs. 22% [108/490]; OR 2.20, 95% CI 1.47 to 3.30).

CONCLUSIONS

Differences in all major outcome measures were markedly better in patients with complete versus incomplete but still 'successful' revascularization using prior thresholds, with ORs in the order of those seen in recent definitive trials comparing EVT to an intravenous tissue plasminogen activator.

Modified Thrombolysis in Cerebral Infarction 2C/Thrombolysis in Cerebral Infarction 3 Reperfusion Should Be the Aim of Mechanical Thrombectomy

Background and Purpose—

Although successful reperfusion is usually defined as a modified Thrombolysis in Cerebral Infarction (mTICI) 2B or 3 at the end of the procedure, studies have shown that mTICI 2B patients had poorer functional outcomes than TICI 3 patients. An mTICI 2C category has been recently introduced for patients with near-complete perfusion except for slow flow in a few distal cortical vessels or presence of small distal cortical emboli after mechanical thrombectomy. The purpose of this study was to evaluate the difference in functional outcome between patients achieving successful reperfusion (ie, mTICI 2B, mTICI 2C, and TICI 3 scores).

Methods—

Ancillary study from the ASTER (Contact Aspiration Versus Stent Retriever for Successful Revascularization) prospective multicenter blinded end point trial. Reperfusion results are reported as the mTICI score, including the mTICI 2C grade. Primary outcome was the percentage of patients with favorable outcome defined as a 90-day modified Rankin Scale score of 0 to 2.

Results—

Two hundred ninety patients with successful reperfusion (mTICI ≥2B), harboring ischemic stroke secondary to occlusion of the anterior circulation within 6 hours of onset of symptoms, undergoing mechanical thrombectomy by contact aspiration or stent retriever were included. Favorable outcome (pre-specified as primary outcome of this ancillary study) did not differ significantly between the 3 reperfusion grades, with a similar positive effect of 2C (odds ratio, 1.71; 95% confidence interval, 0.98–3.00) and 3 (odds ratio, 1.73; 95% confidence interval, 0.88–3.41) grades compared with 2B grade. After combining grades 2C and 3, patients had a significantly higher rate of favorable outcome than patients with 2B (odds ratio, 1.72; 95% confidence interval, 1.01–2.90; P =0.043). Favorable outcome rate decreased with increasing onset-to-reperfusion time, with no significant interaction between mTICI 2C/3 grade and onset-to-reperfusion time on favorable outcome.

Conclusions—

Combining mTICI 2C and TICI 3 grades helps to determine a subgroup of patients achieving better functional outcomes than mTICI 2B patients. Achieving mTICI 2C/3 reperfusion should be the new aim of mechanical thrombectomy for anterior circulation LVO.

Impact of onset-to-groin puncture time within three hours on functional outcomes in mechanical thrombectomy for acute large-vessel occlusion

Introduction Endovascular treatment for acute ischemic stroke with acute large-vessel occlusion (ALVO) has established benefits, and rapid treatment is vital for mechanical thrombectomy in ALVO. Time from onset of stroke to groin puncture (OTP) is a practical and useful clinical marker, and OTP should be shortened to obtain the maximum benefit of thrombectomy. Objective The aim of the present study was to assess the impact of early treatment of anterior circulation stroke within three hours after symptom onset and to evaluate the role of OTP in determining outcomes after endovascular therapy. Methods Consecutive patients with acute stroke due to major artery (internal carotid or middle cerebral arteries) occlusion who underwent endovascular recanalization between March 2014 and January 2017 were retrospectively evaluated. Patients were stratified by OTP into three categories: 0-≤3 h, >3-≤6 h, and >6 h. The primary outcome measure was a 90-day modified Rankin scale score of 0-2 (good outcome). Results Data were analyzed from 100 patients (mean age, 76.6 years; mean National Institutes of Health Stroke Scale score, 17). Groin puncture occurred within 0-≤3 h in 51 patients, >3-≤6 h in 28, and >6 h in 21. Median OTP in each group was 126 min (range, 57-168 min), 238 min (range, 186-360 min) and 728 min (range, 365-1492 min), respectively. On multivariable logistic regression analysis, category of OTP represented an independent predictor of patient outcome (adjusted odds ratio, 0.48; 95% confidence interval, 0.25-0.93; p = 0.029). Conclusions OTP is a prehospital and in-hospital workflow-based indicator. In this single-center study, OTP was found to independently affect functional outcomes after endovascular stroke treatment.

Impact of time to endovascular reperfusion on outcome differs according to the involvement of the proximal MCA territory

BACKGROUND

The time interval between symptom onset and reperfusion is a major determinant of the benefit of endovascular therapy (ET) and patients' outcome. The impact of time may be attenuated in patients with robust collaterals. However, not all regions in the middle cerebral artery (MCA) territory have access to collaterals.

PURPOSE

To evaluate if the involvement of the poorly collateralized proximal MCA territory has an impact on the degree of time dependency of patients' outcome.

METHODS

Patients with MCA occlusions treated with ET and involvement/sparing of the proximal striatocapsular MCA territory (SC+/SC-, each n=97) were matched according to their symptom onset to reperfusion times (SORTs). Correlation and impact of time on outcome was evaluated with strata of SC+/SC- using multivariate logistic regression models (LRMs), including interaction terms. Discharge National Institute of Health Stroke Scale (NIHSS-DIS) score <5 and discharge modified Rankin Scale (mRS-DIS) score ≤2 were prespecified outcome measures.

RESULTS

A stronger correlation between all outcome measures (NIHSS-DIS/ΔNIHSS/mRS-DIS) and SORTs was found for SC+ patients than for SC-patients. SORTs were significant variables in LRMs for mRS-DIS score ≤2 and NIHSS-DIS score <5 in SC+ but not in SC- patients. Interaction of SC+ and SORTs was significant in LRMs for both endpoints.

CONCLUSION

Time dependency of outcome after ET is more pronounced if parts of the proximal MCA territory are affected. This may reflect the lack of collateralization in the striatocapsular region and a more stringent cell death with time. If confirmed, this finding may affect the selection of patients based on different time windows according to the territory at risk.