Real-world effects of late window neurothrombectomy: procedure rates increase without night-time bias

Mechanical Thrombectomy Versus Best Medical Treatment in the Late Time Window in Non-DEFUSE-Non-DAWN Patients: A Multicenter Cohort Study

BACKGROUND

We assessed the efficacy and safety of mechanical thrombectomy (MT) in adult stroke patients with anterior circulation large vessel occlusion presenting in the late time window not fulfilling the DEFUSE-3 (Thrombectomy for Stroke at 6 to 16 Hours With Selection by Perfusion Imaging trial) and DAWN (Thrombectomy 6 to 24 Hours After Stroke With a Mismatch Between Deficit and Infarct trial) inclusion criteria.

METHODS

Cohort study of adults with anterior circulation large vessel occlusion admitted between 6 and 24 hours after last-seen-well at 5 participating Swiss stroke centers between 2014 and 2021. Mismatch was assessed by computer tomography or magnetic resonance imaging perfusion with automated software (RAPID or OLEA). We excluded patients meeting DEFUSE-3 and DAWN inclusion criteria and compared those who underwent MT with those receiving best medical treatment alone by inverse probability of treatment weighting using the propensity score. The primary efficacy end point was a favorable functional outcome at 90 days, defined as a modified Rankin Scale score shift toward lower categories. The primary safety end point was symptomatic intracranial hemorrhage within 7 days of stroke onset; the secondary was all-cause mortality within 90 days.

RESULTS

Among 278 patients with anterior circulation large vessel occlusion presenting in the late time window, 190 (68%) did not meet the DEFUSE-3 and DAWN inclusion criteria and thus were included in the analyses. Of those, 102 (54%) received MT. In the inverse probability of treatment weighting analysis, patients in the MT group had higher odds of favorable outcomes compared with the best medical treatment alone group (modified Rankin Scale shift: acOR, 1.46 [1.02-2.10]; P=0.04) and lower odds of all-cause mortality within 90 days (aOR, 0.59 [0.37-0.93]; P=0.02). There were no significant differences in symptomatic intracranial hemorrhage (MT versus best medical treatment alone: 5% versus 2%, P=0.63).

CONCLUSIONS

Two out of 3 patients with anterior circulation large vessel occlusion presenting in the late time window did not meet the DEFUSE-3 and DAWN inclusion criteria. In these patients, MT was associated with higher odds of favorable functional outcomes without increased rates of symptomatic intracranial hemorrhage. These findings support the enrollment of patients into ongoing randomized trials on MT in the late window with more permissive inclusion criteria.

Outcomes of Stroke Thrombectomy Performed by Interventional Radiologists vs Neurointerventional Physicians

PURPOSE

To test the hypothesis that interventional radiologists (IR) have outcomes for endovascular stroke thrombectomy (EVT) similar to Neurointerventional (NI) physicians and could be used to improve availability of thrombectomy.

MATERIALS AND METHODS

Eight hospitals providing EVT performed by IR and NI in the same institution submitted sequential retrospective data limited to the era of modern devices. Good clinical outcome (90 day modified Rankin score 0-2) and successful revascularization (modified Thrombolysis in Cerebral Infarction score > 2b) were compared between specialties, adjusted for treating hospital, patient age, stroke severity, Alberta Stroke Program Early CT Score (ASPECTS), time from symptom onset to door, and clot location. Propensity score matching was used to compare outcomes. A total of 1009 patients were entered (622 treated by IR and 387 treated by NI).

RESULTS

Median stroke onset to puncture was 245 vs 253 minutes (p=.49), technically successful revascularization was 81.8% vs 82.4% (p=.81), and good clinical outcome was 45.5% vs 50.1% (p=.16), respectively. After adjusting, physician specialty was not a significant predictor of good clinical outcome (odds ratio 1.028 [95% CI 0.760-1.390]; p=.86). After matching, mRS 0-2 was 47.7% for IR and 51.1% for NI (p=0.366).

CONCLUSION

There was no significant difference in successful revascularization and good clinical outcomes between IR and NI physicians. Outcomes by IR were similar to NI outcomes from previously published trials and registries. This may be useful to address coverage and access to stroke interventions.

Stroke Center Designations, Neurointerventionalist Demand, and the Finances of Stroke Thrombectomy in the United States

PURPOSE OF THE REVIEW

This article aims to provide an update on the designation of stroke centers, neurointerventionalist demand, and cost-effectiveness of stroke thrombectomy in the United States.

RECENT FINDINGS

There are now more than 1,660 stroke centers certified by national accrediting bodies in the United States, 306 of which are designated as thrombectomy-capable or comprehensive stroke centers. Considering the amount of nationally certified centers and the number of patients with acute stroke eligible for thrombectomy, each center would be responsible for 64 to 104 thrombectomies per year. As a result, there is a growing demand placed on neurointerventionalists, who have the ability to alter the trajectory of large vessel occlusive strokes. Numbers needed to achieve functional independence after stroke thrombectomy at 90 days range from 3.2 to 7.4 patients in the early time window and 2.8 to 3.6 patients in the extended time window in appropriately selected candidates. With the low number needed to treat, in a variety of valued-based calculations and cost-effectiveness analyses, stroke thrombectomy has proved to be both clinically effective and cost-effective.

SUMMARY

Advancements in the early recognition and treatment of stroke have been paralleled by a remodeling of health care systems to ensure best practices in a timely manner. Stroke center-accrediting bodies provide oversight to safeguard these standards. As successful trial data from high volume centers transform into real-world experience, we must continue to re-evaluate cost-effectiveness, strike a balance between sufficient case volumes to maintain clinical excellence vs the burden and burnout associated with call responsibilities, and improve access to care for all.

Factors Associated With Decreased Accuracy of Modified Thrombolysis in Cerebral Infarct Scoring Among Neurointerventionalists During Thrombectomy

Background and Purpose

The modified Thrombolysis in Cerebral Infarct (mTICI) score is used to grade angiographic outcome after endovascular thrombectomy. We sought to identify factors that decrease the accuracy of intraprocedural mTICI.

Methods

We performed a 2-center retrospective cohort study comparing operator (n=6) mTICI scores to consensus scores from blinded adjudicators. Groups were also assessed by dichotomizing mTICI scores to 0–2a versus 2b–3.

Results

One hundred thirty endovascular thrombectomy procedures were included. Operators and adjudicators had a pairwise agreement in 96 cases (73.8%). Krippendorff α was 0.712. Multivariate analysis showed endovascular thrombectomy overnight (odds ratio [OR]=3.84 [95% CI, 1.22–12.1]), lacking frontal (OR, 5.66 [95 CI, 1.36–23.6]), or occipital (OR, 7.18 [95 CI, 2.12–24.3]) region reperfusion, and higher operator mTICI scores (OR, 2.16 [95 CI, 1.16–4.01]) were predictive of incorrectly scoring mTICI intraprocedurally. With dichotomized mTICI scores, increasing number of passes was associated with increased risk of operator error (OR, 1.93 [95 CI, 1.22–3.05]).

Conclusions

In our study, mTICI disagreement between operator and adjudicators was observed in 26.2% of cases. Interventions that took place between 22:30 and 4:00, featured frontal or occipital region nonperfusion, higher operator mTICI scores, and increased number of passes had higher odds of intraprocedural mTICI inaccuracy.

Investigating the "Weekend Effect" on Outcomes of Patients Undergoing Endovascular Mechanical Thrombectomy for Ischemic Stroke

OBJECTIVES

With growing evidence of its efficacy for patients with large-vessel occlusion (LVO) ischemic stroke, the use of endovascular thrombectomy (EVT) has increased. The "weekend effect," whereby patients presenting during weekends/off hours have worse clinical outcomes than those presenting during normal working hours, is a critical area of study in acute ischemic stroke (AIS). Our objective was to evaluate whether a "weekend effect" exists in patients undergoing EVT.

METHODS

This retrospective, cross-sectional analysis of the 2016-2018 Nationwide Inpatient Sample data included patients ≥18 years with documented diagnosis of ischemic stroke (ICD-10 codes I63, I64, and H34.1), procedural code for EVT, and National Institutes of Health Stroke Scale (NIHSS) score; the exposure variable was weekend vs. weekday treatment. The primary outcome was in-hospital death; secondary outcomes were favorable discharge, extended hospital stay (LOS), and cost. Logistic regression models were constructed to determine predictors for outcomes.

RESULTS

We identified 6052 AIS patients who received EVT (mean age 68.7±14.8 years; 50.8% female; 70.8% White; median (IQR) admission NIHSS 16 (10-21). The primary outcome of in-hospital death occurred in 560 (11.1%); the secondary outcome of favorable discharge occurred in 1039 (20.6%). The mean LOS was 7.8±8.6 days. There were no significant differences in the outcomes or cost based on admission timing. In the mixed-effects models, we found no effect of weekend vs. weekday admission on in-hospital death, favorable discharge, or extended LOS.

CONCLUSION

These results demonstrate that the "weekend effect" does not impact outcomes or cost for patients who undergo EVT for LVO.

Trends in mechanical thrombectomy and decompressive hemicraniectomy for stroke: A multicenter study

BACKGROUND AND PURPOSE

Acute ischemic stroke has increasingly become a procedural disease following the demonstrated benefit of mechanical thrombectomy (MT) for emergent large vessel occlusion (ELVO) on clinical outcomes and tissue salvage in randomized trials. Given these data and anecdotal experience of decreased numbers of decompressive hemicraniectomies (DHCs) performed for malignant cerebral edema, we sought to correlate the numbers of strokes, thrombectomies, and DHCs performed over the timeline of the 2013 failed thrombolysis/thrombectomy trials, to the 2015 modern randomized MT trials, to post-DAWN and DEFUSE 3.

MATERIALS AND METHODS

This is a multicenter retrospective compilation of patients who presented with ELVO in 11 US high-volume comprehensive stroke centers. Rates of tissue plasminogen activator (tPA), thrombectomy, and DHC were determined by current procedural terminology code, and specificity to acute ischemic stroke confirmed by each institution. Endpoints included the incidence of stroke, thrombectomy, and DHC and rates of change over time.

RESULTS

Between 2013 and 2018, there were 55,247 stroke admissions across 11 participating centers. Of these, 6145 received tPA, 4122 underwent thrombectomy, and 662 patients underwent hemicraniectomy. The trajectories of procedure rates over time were modeled and there was a significant change in MT rate (p = 0.002) without a concomitant change in the total number of stroke admissions, tPA administration rate, or rate of DHC.

CONCLUSIONS

This real-world study confirms an increase in thrombectomy performed for ELVO while demonstrating stable rates of stroke admission, tPA administration and DHC. Unlike prior studies, increasing thrombectomy rates were not associated with decreased utilization of hemicraniectomy.

Ambulance waiting and associated work flow improvement strategies: a pilot study to improve door-in-door-out time for thrombectomy patients in a primary stroke center

BACKGROUND

Rapid access to thrombectomy for patients with large vessel occlusion (LVO) acute ischemic stroke (AIS) is critical for improving outcome. A major challenge for the 'drip and ship' model is reducing the door-in-door-out time (DIDO). We propose a new protocol with the aim of reducing DIDO, without adversely affecting emergency service usage time.

METHODS

Consecutive patients with suspected LVO AIS admitted to a Primary Stroke Center (PSC) from October 2018 to January 2021 were included. On arrival, the ambulance crew remained with the patient. Following immediate clinical and radiological evaluation, patients were transferred to the Comprehensive Stroke Center (CSC) by the same waiting crew. Key time metrics were collected and compared with historical data prior to the new protocol.

RESULTS

27 patients had an LVO amenable for mechanical thrombectomy during the time period. There was a significant reduction in the DIDO times compared with the historical group (median 45 min vs 96 min; p<0.0001). There was no significant difference in ambulance usage time between the two time periods (median 53 min vs 45 min; p=0.530). There was an increase in ambulance usage time in FAST-positive patients not for transfer in the pilot group compared with FAST-positive patients not for transfer in the historical group (27 min vs 58 min; p<0.001). In addition, door-to-needle times (24 min vs 40 min; p=0.018) and door-to-CT times (11 min vs 25 min; p<0.0001) improved between the two groups.

CONCLUSION

Our data show a significant reduction in the DIDO for patients transferred for thrombectomy, with no adverse effects on ambulance usage time.

POSITIVE: Perfusion imaging selection of ischemic stroke patients for endovascular therapy

BACKGROUND

The PerfusiOn imaging Selection of Ischemic sTroke patIents for endoVascular thErapy (POSITIVE) trial was designed to evaluate functional outcome in patients with emergent large vessel occlusion (ELVO) presenting within 0-12 hours with pre-specified bifurcated arms of early and late window presentation, who were selected for endovascular thrombectomy with non-vendor specific commercially available perfusion imaging software. Recent trials demonstrating the benefit of thrombectomy up to 16-24 hours following ELVO removed equipoise to randomize late window ELVO patients and therefore the trial was halted.

METHODS

Up to 200 patients were to be enrolled in this FDA-cleared, prospective, randomized, multicenter international trial to compare thrombectomy and best medical management in patients with ELVO ineligible for or refractory to treatment with IV tissue plasminogen activator (IV-tPA) selected with perfusion imaging and presenting within 0-12 hours of last seen normal. The primary outcome was 90-day clinical outcome as measured by the raw modified Rankin Scale (mRS) with scores 5 and 6 collapsed (mRS shift analysis).

RESULTS

The POSITIVE trial suspended enrollment with the release of results from the DAWN trial and was stopped after the release of the DEFUSE 3 trial results. Thirty-three patients were enrolled (21 for medical management and 12 for thrombectomy). Twelve of the 33 patients were enrolled in the 6-12 hour cohort. Despite the early cessation, the primary outcome demonstrated statistically significant superior clinical outcomes for patients treated with thrombectomy (P=0.0060). The overall proportion of patients achieving an mRS score of 0-2 was 75% in the thrombectomy cohort and 43% in the medical management cohort (OR 4.00, 95% CI 0.84 to 19.2).

CONCLUSION

POSITIVE supports the already established practice of delayed thrombectomy for appropriately selected patients presenting within 0-12 hours selected by perfusion imaging from any vendor. The results of the POSITIVE trial are consistent with other thrombectomy trials. The statistically significant effect on functional improvement, despite the small number of patients, reinforces the robust benefits of thrombectomy.

CLINICAL TRIAL REGISTRATION

NCT01852201.

Analysis of Mechanical Thrombectomy for Acute Ischemic Stroke on Nights and Weekends Versus Weekdays at Comprehensive Stroke Centers

OBJECTIVE

The "weekend effect" has been shown to affect outcomes in acute ischemic stroke. We sought to compare metrics and outcomes of emergent stroke thrombectomy at three affiliated comprehensive stroke centers on weekdays versus nights/weekends for a three-year period beginning in 2015, when thrombectomy became common practice for large vessel occlusion acute ischemic stroke.

METHODS

We performed a retrospective analysis of all stroke thrombectomy patients treated from 2015 to 2018 to compare standard thrombectomy metrics and outcomes in patients presenting during weekdays or nights/weekends.

RESULTS

Two hundred-sixteen mechanical thrombectomy cases were evaluated, with 50.9% of patients presenting on weekdays and 49.1% presenting on nights/weekends. There were no statistical differences in baseline characteristics in demographics, stroke risk factors, or stroke severity, but patients presenting on nights/weekends had longer times from last known normal to presentation (130 versus 72.5 minutes, p=0.03). Door-to-groin times were delayed in patients presenting on nights/weekends compared to weekdays (median 104.5 versus 86 minutes, respectively; p=0.007) but groin-to-reperfusion times were similar (51.5 versus 48 minutes, respectively; p=0.4). Successful reperfusion was similar in both groups (90.6% nights/weekends versus 90% weekdays; p=1.0) as were the incidence of symptomatic intracerebral hemorrhage (10.4% nights/weekend versus 7.3% weekdays; p=0.48) and 90-day good functional outcomes based on the modified Rankin Scale did not differ between the two groups in a shift analysis (p=0.545).

CONCLUSIONS

Despite delays in door-to-groin puncture times in acute ischemic stroke patients presenting on nights/weekends compared to weekdays, we did not identify significant differences in successful reperfusion or functional outcomes in this cohort. Further studies are warranted to continue to evaluate differences in stroke care on nights/weekends versus weekdays.

Increased telestroke call burden after the extended thrombectomy window trials

INTRODUCTION

Clinical trials have proven the efficacy of mechanical thrombectomy in stroke patients with large-vessel occlusion presenting within 24 hours of symptom onset. Extending the thrombectomy window to 24 hours resulted in a higher number of thrombectomies being performed. However, little is known about the impact of the extended thrombectomy window on the telestroke call burden.

METHODS

We used the prospectively maintained database of a telestroke network covering a large geographic area in the Southeast USA. We included patients presenting between January 2015 and December 2019. We compared the characteristics and outcomes between patients who presented before and after the publication of the extended window thrombectomy trials.

RESULTS

A total of 9041 patients presented with stroke-like symptoms during the study period. Of these, 4995 presented after February 2018. There was no difference in the patient demographics in both groups. However, patients in the post extended window group had a lower National Institute of Health Stroke Scale on presentation (3 vs. 4; p < 0.001) and longer symptom-onset-to-door time (124 vs. 85 minutes; p < 0.001). The number of consults per month nearly doubled (200 vs. 103; p < 0.001) in the extended thrombectomy window era. Similarly, the number of mechanical thrombectomies performed per month increased from four to seven since extending the thrombectomy window (p < 0.001).

DISCUSSION

The number of telestroke consults nearly doubled after the publication of the extended thrombectomy window trials, with an increase in the number of thrombectomies performed. These findings have important operational implications for hospitals implementing telestroke call coverage.

The professional and personal impact of the coronavirus pandemic on US neurointerventional practices: a nationwide survey

BACKGROUND

Little is currently known about the effects of the coronavirus (COVID-19) pandemic on neurointerventional (NI) procedural volumes or its toll on physician wellness.

METHODS

A 37-question online survey was designed and distributed to physician members of three NI physician organizations.

RESULTS

A total of 151 individual survey responses were obtained. Reduced mechanical thrombectomy procedures compared with pre-pandemic were observed with 32% reporting a greater than 50% reduction in thrombectomy volumes. In concert with most (76%) reporting at least a 25% reduction in non-mechanical thrombectomy urgent NI procedures and a nearly unanimous (96%) cessation of non-urgent elective cases, 68% of physicians reported dramatic reductions (>50%) in overall NI procedural volume compared with pre-pandemic. Increased door-to-puncture times were reported by 79%. COVID-19-positive infections occurred in 1% of physician respondents: an additional 8% quarantined for suspected infection. Sixty-six percent of respondents reported increased career stress, 56% increased personal life/family stress, and 35% increased career burnout. Stress was significantly increased in physicians with COVID-positive family members (P<0.05).

CONCLUSIONS

This is the first study designed to understand the effects of the COVID-19 pandemic on NI physician practices, case volumes, compensation, personal/family stresses, and work-related burnout. Future studies examining these factors following the resumption of elective cases and relaxing of social distancing measures will be necessary to better understand these phenomena.

Impact of off-hour endovascular therapy on outcomes for acute ischemic stroke: insights from STAR

BACKGROUND

The off-hour effect has been observed in the medical care of acute ischemic stroke. However, it remains unclear if time of arrival affects revascularization rates and outcomes after endovascular therapy (EVT) for emergent large vessel occlusion (ELVO). We aimed to investigate the clinical outcomes of EVT between on-hour and off-hour admissions.

METHODS

Patients who underwent EVT for ELVO from January 2013 to June 2019 from the STAR Registry were included. Patients were grouped based on time of groin puncture: on-hour period (Monday through Friday, 7:00 am-4:59 pm) and off-hour period (overnight 5:00pm-6:59am and the weekends). Primary outcome was final modified Rankin Scale (mRS) at 90 days on mRS-shift analysis.

RESULTS

A total of 1919 patients were included in the study from six centers. The majority of patients (1169, 60.9%) of patients presented during the off-hour period. The mean age was 68.1 years and 50.5% were women. Successful reperfusion, as defined by a Thrombolysis In Cerebral Infarction (TICI) score of ≥2B, was achieved in 88.8% in the on-hour group and 88.0% in the off-hour group. Good clinical outcome (mRS 0-2) was obtained in 34.4% of off-hour patients and 37.7% of on-hour patients. On multivariable ordinal logistic regression analysis, time of presentation was not associated with worsened outcome (OR 1.150; 95% CI 0.96 to 1.37; P=0.122). Age, admission National Institutes of Health Stroke Scale (NIHSS), baseline mRS, and final TICI score were significantly associated with worse outcomes.

CONCLUSION

There is no statistical difference in functional outcome in acute ischemic stroke patients who underwent EVT during on-hours versus off-hours.

Drivers of variation in 90-day episode payments after mechanical thrombectomy for acute ischemic stroke

BACKGROUND

Although mechanical thrombectomy for acute ischemic stroke from a large vessel occlusion is now the standard of care, little is known about cost variations in stroke patients following thrombectomy and factors that influence these variations.

METHODS

We evaluated claims data for 2016 to 2018 for thrombectomy-performing hospitals within Michigan through a registry that includes detailed episode payment information for both Medicare and privately insured patients. We aimed to analyze price-standardized and risk-adjusted 90-day episode payments in patients who underwent thrombectomy. Hospitals were grouped into three payment terciles for comparison. Statistical analysis was carried out using unpaired t-test, Chi-square, and ANOVA tests.

RESULTS

1076 thrombectomy cases treated at 16 centers were analyzed. The average 90-day episode payment by hospital ranged from $53 046 to $81,767, with a mean of $65 357. A $20 467 difference (35.1%) existed between the high and low payment hospital terciles (P<0.0001), highlighting a significant payment variation across hospital terciles. The primary drivers of payment variation were related to post-discharge care which accounted for 38% of the payment variation (P=0.0058, inter-tercile range $11,977-$19,703) and readmissions accounting for 26% (P=0.016, inter-tercile range $3,315-$7,992). This was followed by professional payments representing 20% of the variation (P<0.0001, inter-tercile range $7525-$9,922), while index hospitalization payment was responsible for only 16% of the 90-day episode payment variation (P=0.10, inter-tercile range $35,432-$41,099).

CONCLUSIONS

There is a wide variation in 90-day episode payments for patients undergoing mechanical thrombectomy across centers. The main drivers of payment variation are related to differences in post-discharge care and readmissions.

Preserving Access: A Review of Stroke Thrombectomy during the COVID-19 Pandemic

Thrombectomy for large-vessel-occlusion stroke is a highly impactful treatment. The spread of coronavirus 19 (COVID-19) across the United States and the globe impacts access to this crucial intervention through widespread societal and institutional changes. In this document, we review the implications of COVID-19 on the emergency care of large-vessel occlusion stroke, reviewing specific infection-control recommendations, available literature, existing resources, and expert consensus. As a population, patients with large-vessel occlusion stroke face unique challenges during pandemics. These are broad in scope. Responses to these challenges through adaptation of stroke systems of care and with imaging, thrombectomy, and postprocedural care are detailed. Preservation of access to thrombectomy must be prioritized for its public health impact. While the extent of required changes will vary by region, tiered planning for both escalation and de-escalation of measures must be a part of each practice. In addition, preparations described serve as templates in the event of future pandemics.

Strategies to reduce the impact of demand for concurrent endovascular thrombectomy

BACKGROUND

The rise in demand for endovascular thrombectomy (EVT) has increased the possibility that multiple patients with acute ischemic stroke may present concurrently and exceed local capacity to provide timely treatment. In this work, we quantitatively compared the efficacy of various strategies to mitigate demand in excess of capacity (DEC).

METHODS

Strategies evaluated included a backup neurointerventional team for 3 hours, 8 hours, or 24 hours per day; a separate pre-intervention imaging team; and a 30% decrease in procedure duration. For each strategy, empirical distributions were used to probabilistically generate arrival time and case duration for 16 000 independent trials repeated across a range of annual case volumes. DEC was calculated from time series representing the number of concurrent cases at each minute of the year for each trial at each case volume.

RESULTS

All strategies decreased DEC compared with baseline. At a representative volume of 250 cases per year, availability of a backup team for 3 hours, 8 hours, and 24 hours per day reduced DEC by 27.0%, 60.3%, and 97.2%, respectively, compared with baseline. Similarly, availability of a pre-intervention imaging team and a 30% decrease in procedure duration reduced DEC by 26.6% and 17.7%, respectively, compared with baseline.

CONCLUSIONS

A backup neurointerventional team, even if available only part time, was an effective strategy for decreasing DEC for EVT. Understanding the actual quantitative benefit of each strategy can facilitate rational cost-benefit analyses underlying the development of efficient and sustainable models of care.