Futile Interhospital Transfer for Endovascular Treatment in Acute Ischemic Stroke

Should they stay or should they go? Stroke transfers across a hospital network pre- and post-implementation of an automated image interpretation and communication platform

BACKGROUND

A key decision facing nonthrombectomy capable (spoke) hospitals is whether to transfer a suspected large vessel occlusion (LVO) patient to a comprehensive stroke center (CSC). In a retrospective cohort study, we investigated the rate of transfers resulting in endovascular thrombectomy (EVT) and associated costs before and after implementation of an artificial intelligence (AI)-based software.

METHODS

All patients with a final diagnosis of acute ischemic stroke presenting across a five-spoke community hospital network in affiliation with a CSC were included. The Viz LVO (Viz.ai, Inc.) software was implemented across the spokes with image sharing and messaging between providers across sites. In a cohort of patients before (pre-AI, December 2018-October 2020) and after (post-AI, October 2020-August 2022) implementation, we compared the EVT rate among ischemic stroke patients transferred out of our health system to the CSC. Secondary outcomes included the EVT rate based on spoke computed tomography angiography (CTA) and estimated transfer costs.

RESULTS

A total of 3113 consecutive eligible patients (mean age 71 years, 50% female) presented to the spoke hospitals with 162 transfers pre-AI and 127 post-AI. The rate of transfers treated with EVT significantly increased (32.1% pre-AI vs. 45.7% post-AI, p = 0.02). There was a sharp increase in CTA use post-AI at the spoke hospitals for all patients and transfers that likely contributed to the increased EVT transfer rate, but prior spoke CTA use alone was not sufficient to account for all improvement in EVT transfer rate (37.2% pre-AI vs. 49.2% post-AI, p = 0.12). In a binary logistic regression model, the odds of an EVT transfer in the intervention period were 1.85 greater as compared to preintervention (adjusted odds ratio 1.85, 95% confidence interval 1.12-3.06). The decrease in non-EVT transfers resulted in an estimated annual benefit of $206,121 in spoke revenue and $119,921 in payor savings (all US dollars).

CONCLUSIONS

The implementation of an automated image interpretation and communication platform was associated with increased CTA use, more transfers treated with EVT, and potential economic benefits.

Thrombus Imaging Characteristics to Predict Early Recanalization in Anterior Circulation Large Vessel Occlusion Stroke

The early management of transferred patients with a large vessel occlusion (LVO) stroke could be improved by identifying patients who are likely to recanalize early. We aim to predict early recanalization based on patient clinical and thrombus imaging characteristics. We included 81 transferred anterior-circulation LVO patients with an early recanalization, defined as the resolution of the LVO or the migration to a distal location not reachable with endovascular treatment upon repeated radiological imaging. We compared their clinical and imaging characteristics with all (322) transferred patients with a persistent LVO in the MR CLEAN Registry. We measured distance from carotid terminus to thrombus (DT), thrombus length, density, and perviousness on baseline CT images. We built logistic regression models to predict early recanalization. We validated the predictive ability by computing the median area-under-the-curve (AUC) of the receiver operating characteristics curve for 100 5-fold cross-validations. The administration of intravenous thrombolysis (IVT), longer transfer times, more distal occlusions, and shorter, pervious, less dense thrombi were characteristic of early recanalization. After backward elimination, IVT administration, DT and thrombus density remained in the multivariable model, with an AUC of 0.77 (IQR 0.72-0.83). Baseline thrombus imaging characteristics are valuable in predicting early recanalization and can potentially be used to optimize repeated imaging workflow.

Direct to angiosuite strategy versus standard workflow triage for endovascular therapy: systematic review and meta-analysis

BACKGROUND

Reducing stroke workflow times when performing endovascular thrombectomy is associated with improvement in clinical outcomes. We compared outcomes among large vessel occlusion (LVO) stroke patients following the direct to angiosuite (DTAS) strategy versus standard workflow (SW) when undergoing endovascular therapy.

METHODS

We conducted a systematic review and meta-analysis to compare rates of functional outcomes, reperfusion, symptomatic intracranial hemorrhage (sICH) and stroke workflow metrics. We included observational studies and clinical trials that compared the DTAS strategy versus SW, and at least one outcome of interest was assessed. Clinical, methodological and statistical heterogeneity were measured, and a random-effects model was used.

RESULTS

12 studies were included in the systematic review and 8 in the meta-analysis (n=2890). The DTAS strategy was associated with significant higher odds of good functional outcome at 90 days (47.3% vs 34.9%; OR 1.58, 95% CI 1.16 to 2.14) and a significant average reduction of door-to-puncture (mean differences (MD) -35.09, 95% CI -49.76 to -20.41) and door-to-reperfusion times (MD -32.88, 95% CI -50.75 to -15.01). We found no differences in sICH (OR 0.80, 95% CI 0.53 to 1.20), mortality (OR 1.00, 95% CI 0.60 to 1.67) or successful reperfusion rates (OR 1.37, 95% CI 0.82 to 2.29). Moreover, the DTAS strategy was associated with greater odds of dramatic clinical improvement at 24 hours (OR 1.79, 95% CI 1.15 to 2.79).

CONCLUSION

Patients undergoing the DTAS strategy had a significant reduction in door-to-puncture and door-to-reperfusion times. This resulted in an increased rate of early neurological and 90-day functional recovery without compromising safety in LVO patients undergoing endovascular thrombectomy.

Outcomes of Telestroke Inter-Hospital Transfers Among Intervention and Non-Intervention Patients

Background

Telestroke is an established telemedicine method of delivering emergency stroke care. However, not all neurological patients utilizing telestroke service require emergency interventions or transfer to a comprehensive stroke center. To develop an understanding of the appropriateness of inter-hospital neurological transfers utilizing the telemedicine, our study aimed to assess the differences in outcomes of inter-hospital transfers utilizing the service in relation to the need for neurological interventions.

Methods

The pragmatic, retrospective analysis included 181 consecutive patients, who were emergently transferred from telestroke-affiliated regional medical centers between October 3, 2021, and May 3, 2022. In this exploratory study investigating the outcomes of telestroke-referred patients, patients receiving interventions were compared to those that did not following transfer to our tertiary center. Neurological interventions included mechanical thrombectomy (MT) and/or tissue plasminogen activator (tPA), craniectomy, electroencephalography (EEG), or external ventricular drain (EVD). Transfer mortality rate, discharge functional status defined by modified Rankin scale (mRS), neurological status defined by National Institutes of Health Stroke Scale (NIHSS), 30-day unpreventable readmission rate, 90-day clinical major adverse cardiovascular events (MACE), and 90-day mRS, and NIHSS were studied. We used χ2 or Fisher exact tests to evaluate the association between the intervention and categorical or dichotomous variables. Continuous or ordinal measures were compared using Wilcoxon rank-sum tests. All tests of statistical significance were considered to be significant at P < 0.05.

Results

Among the 181 transferred patients, 114 (63%) received neuro-intervention and 67 (37%) did not. The death rate during the index admission was not statistically significant between the intervention and non-intervention groups (P = 0.196). The discharge NIHSS and mRS were worse in the intervention compared to the non-intervention (P < 0.05 each, respectively). The 90-day mortality and cardiovascular event rates were similar between intervention and non-intervention groups (P > 0.05 each, respectively). The 30-day readmission rates were also similar between the two groups (14% intervention vs. 13.4% non-intervention, P = 0.910). The 90-day mRS were not significantly different between intervention and non-intervention groups (median 3 (IQR: 1 - 6) vs. 2 (IQR: 0 - 6), P = 0.109). However, 90-day NIHSS was worse in the intervention compared to non-intervention group (median 2 (IQR: 0 - 11) vs. 0 (IQR: 0 - 3), P = 0.004).

Conclusions

Telestroke is a valuable resource that expedites emergent neurological care via referral to a stroke center. However, not all transferred patients benefit from the transfer process. Future multicenter studies are warranted to study the effects or appropriateness of telestroke networks, and to better understand the patient characteristics, resources allocation, and transferring institutions to improve telestroke care.

Visual review of acute stroke neuroimaging prior to transfer acceptance increases likelihood of endovascular therapy

OBJECTIVES

Demand for thrombectomy, and interhospital transfer to comprehensive stroke centers (CSCs), for acute stroke is increasing. There is an urgent need to identify patients most likely to benefit from transfer. We evaluated whether CSC providers' review of neuroimaging prior to transfer acceptance improved patient selection for thrombectomy and correlated with higher rates of treatment.

MATERIALS AND METHODS

A retrospective database of all patients transferred to Stanford's CSC for thrombectomy between 2015-2019 was used. Pre-acceptance images, when available for visual review, were reviewed by the CSC stroke team via virtual PACS, RAPID software, or LifeImage platforms.

RESULTS

525 patients met inclusion criteria. 147 (28%) had neuroimaging available for review prior to transfer. Of those who did not recanalize en route, 267 (50.8%) underwent thrombectomy. Patients with imaging available for review prior to acceptance were significantly more likely to receive thrombectomy (68% vs 54%, RR 1.26; p=0.006, 95% CI 1.09-1.48). Patient images that were reviewed via RAPID were CT-based perfusion studies; these were more likely to receive thrombectomy (70% vs 54%, RR 1.30; p=0.01, 1.09-1.56). Patients who received EVT were more likely to have had pre-transfer vessel imaging, regardless of availability for visual review (76% vs 59%, RR 1.44; p<0.001, 1.18-1.76).

CONCLUSIONS

Patients with concern for acute stroke transferred for consideration of thrombectomy who had neuroimaging visually reviewed prior to transfer acceptance and did not recanalize by time of arrival were significantly more likely to undergo thrombectomy. Additional prospective studies are needed to confirm our findings.

Determinants of Infarct Core Growth During Inter-hospital Transfer for Thrombectomy

OBJECTIVE

Patients with acute ischemic stroke harboring a large vessel occlusion who present to primary stroke centers often require inter-hospital transfer for thrombectomy. We aimed to determine clinical and imaging factors independently associated with fast infarct growth (IG) during inter-hospital transfer.

METHODS

We retrospectively analyzed data from acute stroke patients with a large vessel occlusion transferred for thrombectomy from a primary stroke center to one of three French comprehensive stroke centers, with an MRI obtained at both the primary and comprehensive center before thrombectomy. Inter-hospital IG rate was defined as the difference in infarct volumes on diffusion-weighted imaging between the primary and comprehensive center, divided by the delay between the two MRI scans. The primary outcome was identification of fast progressors, defined as IG rate ≥5 mL/hour. The hypoperfusion intensity ratio (HIR), a surrogate marker of collateral blood flow, was automatically measured on perfusion imaging.

RESULTS

A total of 233 patients were included, of whom 27% patients were fast progressors. The percentage of fast progressors was 3% among patients with HIR < 0.40 and 71% among those with HIR ≥ 0.40. In multivariable analysis, fast progression was independently associated with HIR, intracranial carotid artery occlusion, and exclusively deep infarct location at the primary center (C-statistic = 0.95; 95% confidence interval [CI], 0.93-0.98). IG rate was independently associated with good functional outcome (adjusted OR = 0.91; 95% CI, 0.83-0.99; P = 0.037).

INTERPRETATION

Our findings show that a HIR > 0.40 is a powerful indicator of fast inter-hospital IG. These results have implication for neuroprotection trial design, as well as informing triage decisions at primary stroke centers. ANN NEUROL 2023.

Drip and ship and mothership models of mechanical thrombectomy result in similar outcomes in acute ischemic stroke of the anterior circulation

BACKGROUND

Stroke therapy has been transformed in recent years due to the availability of thrombolysis and mechanical thrombectomy (MT). Whether transferring the patient directly to a comprehensive stroke center (CSC, mothership model) is better than taking them to a primary stroke center (PSC) and then to a CSC for MT (drip and ship) is unclear but has important implications. We compared the performance of both models in a district of the Basque country, Spain.

METHODS

This is a retrospective analysis of prospectively collected data of all acute ischemic stroke patients consecutively admitted to the Neurology Department of two institutions and eligible for MT over a 36-month period with anterior circulation large vessel occlusion (LVO). One center applied the mothership model and the other the drip-and-ship. The two models were compared in terms of mortality and functional status assessed by modified Rankin (mRS) scale at 90 days. As a surrogate of the effectiveness of the two models, all times pertinent to stroke therapy were recorded.

RESULTS

A total of 187 patients were evaluated subjected to MT with the drip-and-ship model and 188 with mothership, with a median NIHSS of 15. Prior to MT, 17% of the drip-and-ship patients received thrombolysis and 26% in the mothership. Neither mortality rate nor mRS showed statistically significant differences 90 days after stroke. The time lapse from stroke to MT was optimal in both models; albeit being 10 minutes longer in the drip-and-ship model, it had no impact on patients' outcomes.

CONCLUSIONS

Drip-and-ship and mothership models can provide optimal and similar results in acute stroke patients in terms of mortality and functional status at 90 days. Their coexistence may alleviate the burden of CSC thus facilitating the access of more stroke patients to advanced therapies in an equitable manner.

Predictors of unfavorable outcome at 90 days in basilar artery occlusion patients

BACKGROUND

In a previous study, basilar artery occlusion (BAO) was shown to lead to death or disability in 80% of the patients. The treatment for BAO patients in the acute stage includes thrombolysis and intra-arterial thrombectomy, but not all patients benefit from these treatments. Thus, understanding the predictors of outcome before initiating these treatments is of special interest.

AIM

To determine the predictors related to the 90-d clinical outcome in patients with BAO in an Asian population.

METHODS

We performed a retrospective case review of patients admitted to a tertiary stroke center between 2015 and 2019. We used the international classification of diseases-10 criteria to identify cases of posterior circulation stroke. A neurologist reviewed every case, and patients fulfilling the criteria defined in the Basilar Artery International Cooperation Study were included. We then analyzed the patients’ characteristics and factors related to the 90-d outcome.

RESULTS

We identified a total of 99 patients as real BAO cases. Of these patients, 33 (33.3%) had a favorable outcome at 90 d (modified Rankin Scale: 0–3). Moreover, 72 patients received intra-arterial thrombectomy, while 13 patients received intravenous tissue-type plasminogen activator treatment. We observed a favorable outcome in 33.3% of the cases and an unfavorable outcome in 66.7% of the cases. We found that the initial National Institutes of Health Stroke Scale (NIHSS) score and several BAO symptoms, including impaired consciousness, tetraparesis, and pupillary abnormalities, were significantly associated with an unfavorable outcome (P < 0.05), while cerebellar symptoms were associated with a favorable outcome (P < 0.05). In the receiver operating characteristic (ROC) analysis, the areas under the ROC curve of initial NIHSS score, impaired consciousness, tetraparesis, cerebellar symptoms, and pupillary abnormalities were 0.836, 0.644, 0.727, 0.614, and 0.614, respectively. Initial NIHSS score showed a higher AUROC (0.836) compared to BAO symptoms.

CONCLUSION

The most important predictor of an unfavorable outcome was the initial NIHSS score. BAO symptoms, including tetraparesis, impaired consciousness, and pupillary abnormality were also related to an unfavorable outcome.

Impact of Telestroke Implementation on Emergency Department Transfer Rate

BACKGROUND

and Purpose: Telestroke networks are associated with improved outcomes from acute ischemic stroke(AIS) patient and facilitate greater access to care, particularly in underserved regions. These networks also have the potential to influence patient disposition through avoiding unnecessary interhospital transfers. This study examines the impact of implementation of the VA National Telestroke Program (NTSP) on interhospital transfer among Veterans.

METHODS

We analyzed AIS patients presenting to the emergency department 21 VA hospitals before and after telestroke implementation. Transfer rates were determined through review of administrative data and chart review and patient and facility level characteristics were collected to identify predictors of transfer. Comparisons were made using t-test, Wilcoxon rank sum, and chi-square analysis. Multivariable logistic regression with sensitivity analyses were conducted to assess the influence of telestroke implementation on transfer rates.

RESULTS

We analyzed 3,488 stroke encounters (1,056 pre-NTSP and 2,432 post-NTSP). Following implementation, we observed an absolute 14.4% decrease in transfers across all levels of stroke center designation. Younger age, higher stroke severity, and shorter duration from symptom onset were associated with transfer. At the facility level, hospitals with lower annual stroke volume were more likely to transfer although only one hospital actually saw an increase in transfer rates following implementation. After adjusting for patient and facility characteristics, the implementation of VA NTSP resulted in a nearly 60% reduction in odds of transfer (OR = 0.39, [0.19, 0.77]).

CONCLUSIONS

In addition to improving treatment in acute stroke, telestroke networks have the potential to positively impact the efficiency of interhospital networks through disposition optimization and the avoidance of unnecessary transfers.

Modeling the Impact of Prehospital Triage on a True-Life Drip and Ship Mechanical Thrombectomy Urban Patient Cohort

Objective

The aim of the study was to model the effect of prehospital triage of emergent large vessel occlusion (ELVO) to endovascular capable center (ECC) on the timing of thrombectomy and intravenous (IV) thrombolysis using real-world data from a multihospital system.

Methods

We selected a cohort of 77 consecutive stroke patients who were brought by emergency medical services (EMS) to a nonendovascular capable center and then transferred to an ECC for mechanical thrombectomy (MT) (“actual” drip and ship [DS] cohort). We created a hypothetical scenario (bypass model [BM]), modeling transfer of the patients directly to an ECC, based on patients' initial EMS pickup address and closest ECC. Using another cohort of 73 consecutive patients, who were brought directly to an ECC by EMS and underwent endovascular intervention, we calculated mean door-to-needle and door-to-arterial puncture (AP) times (“actual” mothership [MS] cohort). Timings in the actual MS cohort and the actual DS cohort were compared to timings from the BM cohort.

Results

Median first medical contact (FMC) to IV thrombolysis time was 87.5 min (interquartile range [IQR] = 38) for the DS versus 78.5 min (IQR = 8.96) for the BM cohort, with p = 0.1672. Median FMC to AP was 244 min (IQR = 97) versus 147 min (IQR = 8.96) (p < 0.001), and median FMC to TICI 2B+ time was 299 min (IQR = 108.5) versus 197 min (IQR = 8.96) (p < 0.001) for the DS versus BM cohort, respectively.

Conclusions

Modeled EMS prehospital triage of ELVO patients' results in shorter MT times without a change in thrombolysis times. As triage tools increase in sensitivity and specificity, EMS triage protocols stand to improve patient outcomes.

Association of CT-Based Hypoperfusion Index With Ischemic Core Enlargement in Patients With Medium and Large Vessel Stroke

BACKGROUND AND OBJECTIVES

The rate of infarct core progression in patients with acute ischemic stroke is variable and affects outcome of reperfusion therapy. We evaluated the hypoperfusion index (HI) to estimate the initial rate of core progression in patients with medium vessel occlusion (MeVO) compared to large vessel occlusion (LVO) stroke and within a larger time frame since stroke onset.

METHODS

Core progression was assessed in 106 patients with acute stroke and CT perfusion. Using reperfusion trial core time criteria, fast progressors had core >70 mL within 6 hours of stroke onset and slow progressors had core ≤70 mL, mismatch ≥15 mL, and mismatch to core ratio ≥1.8 within 6 to 24 hours. The relationship between HI and infarct core progression (core/time) was examined using receiver operating characteristics to determine optimal HI cutoff. The HI cutoff was then tested in the overall cohort, compared between MeVO and LVO, and evaluated in patients up to 24 hours from stroke onset to differentiate fast from slow rate of core progression. HI threshold was assessed in a second independent cohort of 110 patients with acute ischemic stroke.

RESULTS

In 106 patients with acute stroke, 6.6% were fast progressors, 27.4% were slow progressors, and 66% were not classified as fast or slow progressor by reperfusion trial core time criteria. HI >0.5 was associated with fast progression and able to distinguish fast from slow progressors (area under the curve [AUC] 0.94; 95% confidence interval [CI] 0.80-0.99). In MeVO (n = 26) HI >0.5 had a core progression of 0.30 mL/min compared to 0.03 mL/min for HI ≤0.5 (p < 0.001). In LVO (n = 80), HI >0.5 had a core progression of 0.26 mL/min compared to 0.02 mL/min for HI ≤0.5 (p < 0.001). In patients not classified as fast or slow progressor by reperfusion trial criteria, those with HI >0.5 had progression rate of 0.21 mL/min compared to 0.03 mL/min for those with HI ≤0.5 (p < 0.001). Validation in a second cohort of patients with acute ischemic stroke (n = 110; MeVO = 42, LVO = 68) yielded similar results for HI >0.5 to distinguish fast and slow core progression with an AUC of 0.84 (95% CI 0.72-0.97).

DISCUSSION

HI can differentiate fast from slow core progression in MeVO and LVO within the first 24 hours of acute ischemic stroke. Consideration of core progression rate at time of stroke evaluation may have implications in the selection of patients with MeVO and LVO stroke for reperfusion therapy that warrant further study.

Direct Transfer to Angiosuite in Acute Stroke: Why, When, and How?

Time to reperfusion is one of the strongest predictors of functional outcome in acute stroke due to a large vessel occlusion (LVO). Direct transfer to angiography suite (DTAS) protocols have shown encouraging results in reducing in-hospital delays. DTAS allows bypassing of conventional imaging in the emergency room by ruling out an intracranial hemorrhage or a large established infarct with imaging performed before transfer to the thrombectomy-capable center in the angiography suite using flat-panel CT (FP-CT). The rate of patients with stroke code primarily admitted to a comprehensive stroke center with a large ischemic established lesion is <10% within 6 hours from onset and remains <20% among patients with LVO or transferred from a primary stroke center. At the same time, stroke severity is an acceptable predictor of LVO. Therefore, ideal DTAS candidates are patients admitted in the early window with severe symptoms. The main difference between protocols adopted in different centers is the inclusion of FP-CT angiography to confirm an LVO before femoral puncture. While some centers advocate for FP-CT angiography, others favor additional time saving by directly assessing the presence of LVO with an angiogram. The latter, however, leads to unnecessary arterial punctures in patients with no LVO (3%-22% depending on selection criteria). Independently of these different imaging protocols, DTAS has been shown to be effective and safe in improving in-hospital workflow, achieving a reduction of door-to-puncture time as low as 16 minutes without safety concerns. The impact of DTAS on long-term functional outcomes varies between published studies, and randomized controlled trials are warranted to examine the benefit of DTAS.

Relationship between primary stroke center volume and time to endovascular thrombectomy in acute ischemic stroke

Background and purpose

We investigated whether the annual volume of patients with acute ischemic stroke referred from a primary stroke center (PSC) for endovascular treatment (EVT) is associated with treatment times and functional outcome.

Methods

We used data from the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) registry (2014–2017). We included patients with acute ischemic stroke of the anterior circulation who were transferred from a PSC to a comprehensive stroke center (CSC) for EVT. We examined the association between EVT referral volume of PSCs and treatment times and functional outcome using multivariable regression modeling. The main outcomes were time from arrival at the PSC to groin puncture (PSC‐door‐to‐groin time), adjusted for estimated ambulance travel times, time from arrival at the CSC to groin puncture (CSC‐door‐to‐groin time), and modified Rankin Scale (mRS) score at 90 days after stroke.

Results

Of the 3637 patients in the registry, 1541 patients (42%) from 65 PSCs were included. Mean age was 71 years (SD ± 13.3), median National Institutes of Health Stroke Scale score was 16 (interquartile range [IQR]: 12–19), and median time from stroke onset to arrival at the PSC was 53 min (IQR: 38–90). Eighty‐three percent had received intravenous thrombolysis. EVT referral volume was not associated with PSC‐door‐to‐groin time (adjusted coefficient: −0.49 min/annual referral, 95% confidence interval [CI]: −1.27 to 0.29), CSC‐door‐to‐groin time (adjusted coefficient: −0.34 min/annual referral, 95% CI: −0.69 to 0.01) or 90‐day mRS score (adjusted common odds ratio: 0.99, 95% CI: 0.96–1.01).

Conclusions

In patients transferred from a PSC for EVT, higher PSC volumes do not seem to translate into better workflow metrics or patient outcome.

Reasons for Not Performing Mechanical Thrombectomy: A Population-Based Study of Stroke Codes

[Figure: see text].

Central Triage of Acute Stroke Patients Across a Distributive Stroke Network Is Safe and Reduces Transfer Denials

[Figure: see text].

Use of a Smartphone Application to Speed Up Interhospital Transfer of Acute Ischemic Stroke Patients for Thrombectomy

Background: In most countries, large cerebral artery occlusion is identified as the leading cause of disability. In 2015, five large-scale clinical trials confirmed the benefit of intra-arterial thrombectomy. However, thrombectomy is a highly technical and facility-dependent procedure. Primary stroke centers need to transfer patients to comprehensive stroke centers to perform thrombectomy. The time-lapse during interhospital transfer would decrease the chance of the patient's proper recovery. Communication barriers also contribute to this delay.

Aims: We used a smartphone application to overcome communication barriers between hospitals. We aimed to shorten the door-to-puncture time of interhospital transfer patients.

Methods: We began using a smartphone application, “LINE,” to facilitate interhospital communication on May 01, 2018. We carried out retrospective data analyses for all the transfer patients (n = 351), with the primary outcome being the door-to-puncture time in our comprehensive stroke center (China Medical University Hospital). We compared the three periods: May 01 to Dec 31, 2017 (before the use of the smartphone application); May 01 to Dec 31, 2018 (the 1st year of using the smartphone application); and May 01 to Dec 31, 2019 (the 2nd year of using the smartphone application). We also compared the transfer data with non-transfer thrombectomies in the same period.

Results: We compared 2017, 2018, and 2019 data. The total number of transfer patients increased over the years: 63, 113, 175, respectively. The mean door-to-puncture time decreased significantly, going from 109, through 102, to 92 min. Meanwhile, the mean door-to-puncture time in non-transfer patients were 140.3, 122.1, and 129.3 min. The main reason of time saving was the change of the way of communication, from point-to-point interhospital communication to hub-to-spoke interhospital communication.

Conclusions: We used this smartphone application to enhance interhospital communication, changed from the point-to-point to hub-to-spoke method. It made us overcome the communication barrier and build up interhospital connection, thus shortening the door-to-puncture time. Our experience demonstrated the importance of close communication and teamwork in hyperacute stroke care, especially in interhospital transfer for thrombectomy.

Early recanalization in large-vessel occlusion stroke patients transferred for endovascular treatment

Background

We performed an exploratory analysis to identify patient and thrombus characteristics associated with early recanalization in large-vessel occlusion (LVO) stroke patients transferred for endovascular treatment (EVT) from a primary (PSC) to a comprehensive stroke center (CSC).

Methods

We included patients with an LVO stroke of the anterior circulation who were transferred to our hospital for EVT and underwent repeated imaging between January 2016 and June 2019. We compared patient characteristics, workflow time metrics, functional outcome (modified Rankin Scale at 90 days), and baseline thrombus imaging characteristics, which included: occlusion location, thrombus length, attenuation, perviousness, distance from terminus of intracranial carotid artery to the thrombus (DT), and clot burden score (CBS), between early-recanalized LVO (ER-LVO), and non-early-recanalized LVO (NER-LVO) patients.

Results

One hundred and forty-nine patients were included in the analysis. Early recanalization occurred in 32% of patients. ER-LVO patients less often had a medical history of hypertension (31% vs 49%, P=0.04), and more often had clinical improvement between PSC and CSC (ΔNIHSS −5 vs 3, P<0.01), compared with NER-LVO patients. Thrombolysis administration was similar in both groups (88% vs 78%, P=0.18). ER-LVO patients had no ICA occlusions (0% vs 27%, P<0.01), more often an M2 occlusion (35% vs 17%, P=0.01), longer DT (27 mm vs 12 mm, P<0.01), shorter thrombi (17 mm vs 27 mm, P<0.01), and higher CBS (8 vs 6, P<0.01) at baseline imaging. ER-LVO patients had lower mRS scores (1 vs 3, P=0.02).

Conclusions

Early recanalization is associated with clinical improvement between PSC and CSC admission, more distal occlusions and shorter thrombi at baseline imaging, and better functional outcome.

Progression of cerebral infarction before and after thrombectomy is modified by prehospital pathways

Background

Evidence of the consequences of different prehospital pathways before mechanical thrombectomy (MT) in large vessel occlusion stroke is inconclusive. The aim of this study was to investigate the infarct extent and progression before and after MT in directly admitted (mothership) versus transferred (drip and ship) patients using the Alberta Stroke Program Early CT Score (ASPECTS).

Methods

ASPECTS of 535 consecutive large vessel occlusion stroke patients eligible for MT between 2015 to 2019 were retrospectively analyzed for differences in the extent of baseline, post-referral, and post-recanalization infarction between the mothership and drip and ship pathways. Time intervals and transport distances of both pathways were analyzed. Multiple linear regression was used to examine the association between infarct progression (baseline to post-recanalization ASPECTS decline), patient characteristics, and logistic key figures.

Results

ASPECTS declined during transfer (9 (8–10) vs 7 (6-9), p<0.0001), resulting in lower ASPECTS at stroke center presentation (mothership 9 (7–10) vs drip and ship 7 (6–9), p<0.0001) and on follow-up imaging (mothership 7 (4–8) vs drip and ship 6 (3–7), p=0.001) compared with mothership patients. Infarct progression was significantly higher in transferred patients (points lost, mothership 2 (0–3) vs drip and ship 3 (2–6), p<0.0001). After multivariable adjustment, only interfacility transfer, preinterventional clinical stroke severity, the degree of angiographic recanalization, and the duration of the thrombectomy procedure remained predictors of infarct progression (R²=0.209, p<0.0001).

Conclusions

Infarct progression and postinterventional infarct extent, as assessed by ASPECTS, varied between the drip and ship and mothership pathway, leading to more pronounced infarction in transferred patients. ASPECTS may serve as a radiological measure to monitor the benefit or harm of different prehospital pathways for MT.

The "Flying Intervention Team": A Novel Stroke Care Concept for Rural Areas

BACKGROUND

Endovascular treatment of large vessel occlusion in acute ischemic stroke patients is difficult to establish in remote areas, and time dependency of treatment effect increases the urge to develop health care concepts for this population.

SUMMARY

Current strategies include direct transportation of patients to a comprehensive stroke center (CSC) ("mothership model") or transportation to the nearest primary stroke center (PSC) and secondary transfer to the CSC ("drip-and-ship model"). Both have disadvantages. We propose the model "flying intervention team." Patients will be transported to the nearest PSC; if telemedically identified as eligible for thrombectomy, an intervention team will be acutely transported via helicopter to the PSC and endovascular treatment will be performed on site. Patients stay at the PSC for further stroke unit care. This model was implemented at a telestroke network in Germany. Fifteen remote hospitals participated in the project, covering 14,000 km2 and a population of 2 million. All have well established telemedically supported stroke units, an angiography suite, and a helicopter pad. Processes were defined individually for each hospital and training sessions were implemented for all stroke teams. An exclusive project helicopter was installed to be available from 8 a.m. to 10 p.m. during 26 weeks per year. Key Messages: The model of the flying intervention team is likely to reduce time delays since processes will be performed in parallel, rather than consecutively, and since it is quicker to move a medical team rather than a patient. This project is currently under evaluation (clinicaltrials NCT04270513).

Value of repeated imaging in patients with a stroke who are transferred for endovascular treatment

Background

Patients with a stroke who are transferred to a comprehensive stroke center for endovascular treatment (EVT) often undergo repeated neuroimaging prior to EVT.

Objective

To evaluate the yield of repeating imaging and its effect on treatment times.

Methods

We included adult patients with a large vessel occlusion (LVO) stroke who were referred to our hospital for EVT by primary stroke centers (2016–2019). We excluded patients who underwent repeated imaging because primary imaging was unavailable, incomplete, or of insufficient quality. Outcomes included treatment times and repeated imaging findings.

Results

Of 677 transferred LVO stroke, 551 were included. Imaging was repeated in 165/551 patients (30%), mostly because of clinical improvement (86/165 (52%)) or deterioration (40/165 (24%)). Patients who underwent repeated imaging had higher door-to-groin-times than patients without repeated imaging (median 43 vs 27 min, adjusted time difference: 20 min, 95% CI 15 to 25). Among patients who underwent repeated imaging because of clinical improvement, the LVO had resolved in 50/86 (58%). In patients with clinical deterioration, repeated imaging led to refrainment from EVT in 3/40 (8%). No symptomatic intracranial hemorrhages (sICH) were identified. Ultimately, 75/165 (45%) of patients with repeated imaging underwent EVT compared with 326/386 (84%) of patients without repeated imaging (p<0.01).

Conclusions

Neuroimaging was repeated in 30% of patients with an LVO stroke and resulted in a median treatment delay of 20 minutes. In patients with clinical deterioration, no sICH were detected and repeated imaging rarely changed the indication for EVT. However, in more than half of patients with clinical improvement, the LVO had resolved, resulting in refrainment from EVT.

Negative impact of Interhospital Transfer on Clinical Outcomes of Mechanical Thrombectomy for Fast Progressive Stroke

OBJECTIVES

The time-dependence of the clinical outcome of mechanical thrombectomy is higher in the "fast progressor" in whom cerebral ischemia progresses rapidly. The impact of time-consuming interhospital transfer (IT) on the clinical outcome of such patients is unknown. The effect on clinical outcomes of IT of fast progressors was investigated.

METHODS

Among the patients enrolled in the Tokyo/Tama REgistry of Acute endovascular Thrombectomy, fast progressor cerebral ischemia cases were retrospectively investigated. In this study, a fast progressor was defined as a case with an Alberta Stroke Program Early CT Score less than 6 and last known well (LKW) to arterial puncture within 6 h. Patients' background characteristics, treatment progress, and the modified Rankin Scale (mRS) score at 3 months were examined.

RESULTS

Of a total of 1182 patients, 92 (7.8%) were included, with 76 patients in the direct transfer (DT) group, and 16 patients in the IT group. Median LKW to reperfusion was 190 min and 272 min, respectively (P<.001). The number of patients with mRS scores 0-2 at three months was 22 (28.9%) in the DT group and 1 (6.2%) in the IT group. Interhospital transfer was an independent factor associated with worse outcomes (odds ratio 0.08, 95% confidence interval 0.01-0.87, P=.038).

CONCLUSION

This study showed that, among fast progressor patients, the IT group had a worse prognosis than the DT group. To provide good clinical outcomes for fast progressor patients, those who are likely to undergo mechanical thrombectomy should be sent directly to a thrombectomy-capable center.

Can non-contrast head CT and stroke severity be used for stroke triage? A population-based study

BACKGROUND AND PURPOSE

Acute ischemic stroke (AIS) patients may benefit from endovascular thrombectomy (EVT) up to 24 h since last known normal (LKN). Advanced imaging is required for patient selection. Small or rural hospitals may not have sufficient CT technician and radiology support to rapidly acquire and interpret images. We estimated transfer rates using non-contrast head CT and stroke severity to select patients to be transferred to larger centers for evaluation.

METHODS

We identified all AIS among residents of the study region in 2010. Only cases age ≥ 18 with baseline mRS 0-2 that presented to an ED were included. Among cases that presented between 6 and 24 h from LKN, those without evidence of acute infarct on head CT and with initial NIHSS ≥6 or ≥ 10 were identified.

RESULTS

Of 1359 AIS cases, 448 (33.0%) presented between 6 and 24 h, of which 383 (85.5%) showed no evidence of acute infarct on CT. Of cases with no acute infarct on CT, 89/383 (23.2%) had NIHSS ≥6, of which 66 (74.2%) initially presented to a hospital without thrombectomy capabilities; and 51/383 (13.3%) had NIHSS ≥10, of which 40 (78.4%) presented to a non-thrombectomy hospital.

CONCLUSIONS

In our population, 40-66 AIS patients annually (0.8-1.3/week, or 3-5 patients/100,000 persons/year) may present to non-thrombectomy hospitals and need to be transferred using non-contrast CT and stroke severity as screening tools. Such an approach may sufficiently mitigate the impact of delays in treatment on outcomes, without overburdening the referring nor accepting hospitals.

Stroke transfers for thrombectomy in the era of extended time

BACKGROUND AND PURPOSE

The Dawn and Extend Intra-Arterial (IA) acute stroke intervention trials have proven the benefit of thrombectomy in a select group of patients up to 24 h since their last known well time (LKWT) or time of symptom onset. Following the issuance of new treatment guidelines for large vessel occlusion strokes, we reviewed the paradigm shift effect on transfers for possible thrombectomy in a rural state.

HYPOTHESIS

Extended time window for thrombectomy increases the need for better identification of potential transfers for thrombectomy in rural states with few hospitals capable of 24/7 interventional thrombectomy.

METHODS

We analyzed all transfers to a comprehensive stroke center (CSC) from January to December 2018 which were specifically transferred for possible further intervention. This time period was selected in accordance with the change in American Heart Association (AHA) guidelines for extended time windows in mechanical thrombectomy (MT) care.

RESULTS

A total of 132 patients were transferred for possible thrombectomy and advanced imaging. Thirty-four % patients underwent diagnostic angiogram with 33% patients having successful MT. Of the excluded patients 19% had large core infarcts by the time they arrived at hub hospital, 1.5% had hemorrhagic conversion, 32% had stroke without treatable occlusion not amenable for thrombectomy or cortical strokes on follow-up imaging, and 13.5% did not have stroke or LVO on follow-up imaging.

CONCLUSION

Since the AHA's change in time window guidelines for mechanical thrombectomies, there has been an increased effort in identifying good candidates with computerized tomography angiography (CTA). To avoid undue burden on stroke systems of care, CTA identification of these patients at the spoke hospitals is key along with timely transport to appropriate thrombectomy capable sites. Given the rural nature of this state along with limited resources, selection of patients is a practical issue, especially for avoiding futile transfers, which might be true for large areas of the USA.

Delayed Thrombectomy Center Arrival is Associated with Decreased Treatment Probability

BACKGROUND

Endovascular thrombectomy (EVT) is effective in reducing disability in selected patients with stroke and large vessel occlusion (LVO), but access to this treatment is suboptimal.

AIM

We examined the proportion of patients with LVO who did not receive EVT, the reasons for non-treatment, and the association between time from onset and probability of treatment.

METHODS

We conducted a retrospective cohort study of consecutive patients with acute stroke and LVO presenting between January 2017 and June 2018. We used multivariable log-binomial models to determine the association between time and probability of treatment with and without adjustment for age, sex, dementia, active cancer, baseline disability, stroke severity, and evidence of ischemia on computerized tomography.

RESULTS

We identified 256 patients (51% female, median age 74 [interquartile range, IQR 63.5, 82.5]), of whom 59% did not receive EVT. The main reasons for not treating with EVT were related to occlusion characteristics or infarct size. The median time from onset to EVT center arrival was longer among non-treated patients (218 minutes [142, 302]) than those who were treated (180 minutes [104, 265], p = 0.03). Among patients presenting within 6 hours of onset, the relative risk (RR) of receiving EVT decreased by 3% with every 10-minute delay in arrival to EVT center (adjusted RR 0.97 CI95 [0.95, 0.99]). This association was not found in the overall cohort.

CONCLUSIONS

The proportion of patients with acute stroke and confirmed LVO who do not undergo EVT is substantial. Minimizing delays in arrival to EVT center may optimize the delivery of this treatment.

Impact of EMS bypass to endovascular capable hospitals: geospatial modeling analysis of the US STRATIS registry

BACKGROUND

Routing patients directly to endovascular capable centers (ECCs) would decrease time to mechanical thrombectomy (MT), but may delay intravenous thrombolysis (IVT).

OBJECTIVE

To study the clinical outcomes of patients with a stroke transferred directly to ECCs compared with those transferred to ECCs from non-endovascular capable centers (nECCs).

METHODS

Data from the STRATIS registry were analyzed to evaluate process and clinical outcomes under five routing policies: (1) transport to nearest nECC; (2) transport to STRATIS ECC over any distance or (3) within 20 miles; (4) transport to ideal ECC (iECC), over any distance or (5) within 20 miles.

RESULTS

Among 236 patients, 117 (49.6%) were transferred by ground, of whom 62 (53%) were transferred within 20 miles. Median MT start time was accelerated in all direct transport models. IVT start was prolonged with direct transport across all distances, but accelerated with direct transport to iECC ≤20 miles. With bypass limited to ≤20 miles, the median modeled EMS arrival to IVT interval decreased for both iECCs and ECCs (by 12 min and 6 min, respectively), and median EMS arrival to puncture time decreased by up to 94 min. In this cohort, no patient would have become ineligible for IVT. Bypass to iECC modeling under 20 miles showed a significant reduction in the level of disability at 3 months, with freedom from disability (modified Rankin Scale score 0-1) at 3 months increased by 12%.

CONCLUSIONS

Direct routing of patients with a large vessel occlusion to ECCs, especially when within 20 miles, may lead to better clinical outcomes by accelerating the start of MT without any delay of IVT.

CLINICAL TRIAL REGISTRATION NUMBER

http://www.clinicaltrials.gov. Unique identifier: NCT02239640.

Safety of inter-hospital transfer of patients with acute ischemic stroke for evaluation of endovascular thrombectomy

Stroke networks facilitate access to endovascular treatment (EVT) for patients with ischemic stroke due to large vessel occlusion. In this study we aimed to determine the safety of inter-hospital transfer and included all patients with acute ischemic stroke who were transferred within our stroke network for evaluation of EVT between 06/2016 and 12/2018. Data were derived from our prospective EVT database and transfer protocols. We analyzed major complications and medical interventions associated with inter-hospital transfer. Among 615 transferred patients, 377 patients (61.3%) were transferred within our telestroke network and had transfer protocols available (median age 76 years [interquartile range, IQR 17], 190 [50.4%] male, median baseline NIHSS score 17 [IQR 8], 246 [65.3%] drip-and-ship i.v.-thrombolysis). No patient suffered from cardio-respiratory failure or required emergency intubation or cardiopulmonary resuscitation during the transfer. Among 343 patients who were not intubated prior departure, 35 patients (10.2%) required medical interventions during the transfer. The performance of medical interventions was associated with a lower EVT rate and higher mortality at three months. In conclusion, the transfer of acute stroke patients for evaluation of EVT was not associated with major complications and transfer-related medical interventions were required in a minority of patients.

Cost-Consequence Analysis of Mobile Stroke Units vs. Standard Prehospital Care and Transport

Background: Mobile stroke units (MSUs) are the latest approach to improving time-sensitive stroke care delivery. Currently, there are no published studies looking at the expanded value of the MSU to diagnose and transport patients to the closest most appropriate facility. The purpose of this paper is to perform a cost consequence analysis of standard transport (ST) vs. MSU.

Methods and Results: A cost consequence analysis was undertaken within a decision framework to compare the incremental cost of care for patients with confirmed stroke that were served by the MSU vs. their simulated care had they been served by standard emergency medical services between July 2014 and October 2015. At baseline values, the incremental cost between MSU and ST was $70,613 ($856,482 vs. $785,869) for 355 patient transports. The MSU avoided 76 secondary interhospital transfers and 76 emergency department (ED) encounters. Sensitivity analysis identified six variables that had measurable impact on the model's variability and a threshold value at which MSU becomes the optimal strategy: number of stroke patients (>391), probability of requiring transfer to a comprehensive stroke center (CSC, >0.52), annual cost of MSU operations (<$696,053), cost of air transfer (>$8,841), probability initial receiving hospital is a CSC (<0.32), and probability of ischemic stroke with ST (<0.76).

Conclusions: MSUs can avert significant costs in the administration of stroke care once optimal thresholds are achieved. A comprehensive cost-effectiveness analysis is required to determine not just the operational value of an MSU but also its clinical value to patients and the society.

Prehospital selection of thrombectomy candidates beyond large vessel occlusion

Objective

Current prehospital scales used to detect large vessel occlusion reveal very low endovascular thrombectomy (EVT) rates among selected patients. We developed a novel prehospital scale, the Madrid-Direct Referral to Endovascular Center (M-DIRECT), to identify EVT candidates for direct transfer to EVT-capable centers (EVT-Cs). The scale evaluated clinical examination, systolic blood pressure, and age. Since March 2017, patients closer to a stroke unit without EVT capabilities and an M-DIRECT positive score have been transferred to the nearest EVT-C. To test the performance of the scale-based routing protocol, we compared its outcomes with those of a simultaneous cohort of patients directly transferred to an EVT-C.

Methods

In this prospective observational study of consecutive patients with stroke code seen by emergency medical services, we compared diagnoses, treatments, and outcomes of patients who were closer to an EVT-C (mothership cohort) with those transferred according to the M-DIRECT score (M-DIRECT cohort).

Results

The M-DIRECT cohort included 327 patients and the mothership cohort 214 patients. In the M-DIRECT cohort, 227 patients were negative and 100 were positive. Twenty-four (10.6%) patients required secondary transfer, leaving 124 (38%) patients from the M-DIRECT cohort admitted to an EVT-C. EVT rates were similar for patients with ischemic stroke in both cohorts (30.9% vs 31.5%). The M-DIRECT scale had 79% sensitivity, 82% specificity, and 53% positive predictive value for EVT. Recanalization and independence rates at 3 months did not differ between the cohorts.

Conclusions

The M-DIRECT scale was highly accurate for EVT, with treatment rates and outcomes similar to those of a mothership paradigm, thereby avoiding EVT-C overload with a low rate of secondary transfers.

Emergency management of stroke in the era of mechanical thrombectomy

Emergency management of stroke has been directed at the delivery of recombinant tissue plasminogen activator (tPA) in a timely fashion. Because of the many limitations attached to the delivery of tPA and the perceived benefits accrued to tPA, its use has been limited. Mechanical thrombectomy, a far superior therapy for the largest and most disabling strokes, large vessel occlusions (LVOs), has changed the way acute strokes are managed. Aside from the rush to deliver tPA, there is now a need to identify LVO and refer those patients with LVO to physicians and facilities capable of delivering urgent thrombectomy. Other parts of emergency department management of stroke are directed at identifying and mitigating risk factors for future strokes and at preventing further damage from occurring. We review here the most recent literature supporting these advances in stroke care and present a framework for understanding the role that emergency physicians play in acute stroke care.

Recanalization of Emergent Large Intracranial Vessel Occlusion through Intravenous Thrombolysis: Frequency, Clinical Outcome, and Reperfusion Pattern

BACKGROUND

According to a recent meta-analysis, 1 out of 10 patients with emergent large intracranial vessel occlusion (ELVO) causing stroke have recanalization after intravenous thrombolysis (IVT) alone. However, rate, clinical outcome, and recanalization pattern of this phenomenon are poorly understood.

OBJECTIVES AND METHODS

Patients with ELVO recanalized only by IVT were analyzed, and frequency of recanalization, clinical outcome, safety variables, and reperfusion pattern were assessed. These patients were compared to a group of patients with ELVO who underwent endovascular thrombectomy with or without prior IVT.

RESULTS

Successful or sufficient recanalization after IVT alone occurred in 81 of 760 patients (10.6%) with ELVO who had been referred for endovascular thrombectomy. These 81 patients (group 1) were compared to a group of patients receiving endovascular thrombectomy with prior IVT (group 2) or without (group 3). A good clinical outcome at 90 days was seen in 61.7% of patients in group 1, 32.2% in group 2, and 34.5% in group 3 (p < 0.001). The 3 groups had no significant differences in intracranial hemorrhage. IVT was not independently associated with symptomatic intracranial hemorrhage, parenchymal hematoma, or subarachnoid hemorrhage. Mortality at 90 days was 9.9% in group 1, 20.7% in group 2, and 29.6% in group 3 (p < 0.001). After adjusting for all relevant variables, outcome and mortality differences were nonsignificant. No difference in the rate of successful reperfusion (modified treatment in cerebral ischemia [mTICI] 2b/3) was found. A reperfusion mTICI 3 was achieved in 18.5% in group 1, 60.7% in group 2, and 57.1% in group 3 (p < 0.001). Patients in group 1 had lower chance of achieving a complete recanalization (mTICI 3) compared to patients in group 2, OR 0.15 (95% CI 0.08-0.29) and in group 3, OR 0.17 (95% CI 0.09-0.32; p < 0.001).

CONCLUSIONS

Primary IVT in ELVO caused a recanalization rate of 10.6%, making endovascular treatment either unnecessary or impossible. Early recanalization of ELVO with only IVT is associated with a 61.7% independence rate at 90 days and similar successful reperfusion rates (mTICI2b/3) compared to ELVO treated with endovascular treatment, with or without previous IVT. However, recanalization only through IVT achieves a lower rate of mTICI 3 reperfusion when compared to endovascular treatment.

Review of external referrals to a regional stroke centre: it is not just about thrombectomy

AIMS

To determine the experience of a regional stroke referral centre of external referrals for endovascular thrombectomy (EVT) in patients with symptoms of acute ischaemic stroke (AIS) and large vessel occlusion (LVO).

MATERIALS AND METHODS

Data were collected prospectively over two 4-month periods (2017-2018) on consecutive external referrals for EVT. Baseline demographics, imaging findings, and key time parameters were recorded. Reasons for not transferring patients and for not performing EVT were recorded. Key time intervals were calculated and compared between the transferred and non-transferred group with and without intracranial occlusion and between the transferred patients who underwent thrombectomy and those who did not.

RESULTS

Two hundred and sixty-two patients were referred. Sixty-one percent (n=159) were accepted and transferred for treatment. Of those transferred, 86% (n=136) had EVT. Fourteen percent (n=23) were unsuitable for EVT on arrival due to no vessel occlusion (48% n=11), poor Alberta Stroke Program Early CT Score (ASPECTS)/established infarct (30%, n=7) haemorrhage (9%, n=2), and clinical recovery (13% n=3). One hundred and three patients (39%) were ineligible for EVT following phone discussion due to absence of intracranial occlusion (59%, n=61), low ASPECTS (22%, n=23), distal occlusion (4%, n=4), low/improving National Institutes of Health Stroke Scale (NIHSS; 10.7%, n=11), and poor modified Rankin Scale (mRS) at baseline (3%, n=3). Patients with LVO but not transferred had longer onset to hospital arrival time compared with those transferred 151.5 versus 91 minutes (p<0.005), with a trend also toward a longer door to CT/CTA 40 minutes versus 30 minutes (p=0.142).

CONCLUSION

These data provide valuable insights into the service provision of a comprehensive stroke network. The present rates of EVT and futile transfers are modest compared to published data. Access to neuroradiology and specialised stroke assessment is crucial to optimise time to treatment.

Clinical and neuroimaging criteria to improve the workflow in transfers for endovascular treatment evaluation

Background

Transfer protocols from primary to comprehensive stroke centers are crucial for endovascular treatment success.

Aim

To evaluate clinical and neuroimaging data of transferred patients and their likelihood of presenting a large infarct core at comprehensive stroke center arrival.

Methods

Retrospective analysis of population-based mandatory prospective registry of acute stroke patients evaluated for endovascular treatment. Consecutive patients evaluated at primary stroke center with suspected large vessel occlusion and PSC-ASPECTS ≥ 6 transferred to a comprehensive stroke center were included. PSC and CSC-ASPECTS, time-metrics, and clinical data were analyzed.

Results

During 28 months, 1185 endovascular treatment candidates were transferred from PC to comprehensive stroke center in our public stroke network, 477 had an anterior circulation syndrome and available neuroimaging information and were included. Median baseline NIHSS was 13 (8–19). On arrival to comprehensive stroke center, large vessel occlusion was confirmed in 60.2% patients, and 41.2% received endovascular treatment. Median interfacility ASPECTS decay was 1 (0–2) after a median of 150.7 (SD 101) min between both CT-acquisitions. A logistic regression analysis adjusted by age, time from symptoms to PC-CT, and time from PC-CT to CSC-CT showed that only a baseline NIHSS and PSC-ASPECTS independently predicted a CSC-ASPECTS < 6. ROC curves identified baseline NIHSS ≥ 16 and PSC-ASPECTS ≤ 7 as the best cut-off points. The rate of CSC-ASPECTS < 6 increased from 7% to 57% among patients with NIHSS ≥ 16 and PSC-ASPECS ≤ 7.

Conclusion

After a median transfer time >2 h, only 11.9% showed ASPECTS < 6 at the comprehensive stroke center. Activation of endovascular treatment teams should not require confirming neuroimaging on arrival and repeating neuroimaging at comprehensive stroke center should only be performed in selected cases.

[Mothership or drip and ship?]

BACKGROUND

The scientific evidence of the high efficacy of endovascular stroke treatment in large vessel occlusion (LVO) led to this treatment being accepted as the gold standard in these patients.

OBJECTIVE

This review article presents the various organizational models for thrombectomy and analyzes which model is preferred under which circumstances.

MATERIAL AND METHODS

In an analysis of the recent scientific literature the models for optimizing patient transport (drip and ship or mothership) and optimizing the availability of interventionalists (drip and drive or remote mentoring) are presented and compared. In addition, considerations are made on thrombectomy rates and the prevalence of LVOs and the construction of organizational models.

RESULTS

If the location of the stroke patient is just as far from or closer to a comprehensive stroke center (CSC) than a primary stroke center (PSC), the patient should be transported directly to the CSC by mothership. If, on the other hand, a PSC is closer to the stroke site than a CSC and the time after the onset of symptoms lies within the lysis time window, this decision depends on many variables.

CONCLUSION

Based on the unambiguous data situation, no recommendations can currently be made for a generally superior organizational model.

Endovascular therapy for anterior circulation large vessel occlusion in telestroke

INTRODUCTION

Recent exploratory analysis suggested comparable outcomes among stroke patients undergoing endovascular therapy (EVT) for anterior circulation large vessel occlusion, whether selected via the telestroke network or admitted directly to an EVT-capable centre. We further studied the role of telemedicine in selection of ischaemic stroke patients potentially eligible for EVT.

METHODS

We prospectively included consecutive ischaemic stroke patients with anterior circulation large vessel occlusion who underwent EVT at our neurovascular centre (January 2016 to March 2018). We compared safety and efficacy including symptomatic intracerebral haemorrhage (sICH), successful reperfusion (mTICI 2b/3), 90-day favourable outcome (mRS ≤ 2) and 90-day survival between patients transferred from telestroke hospitals and patients directly admitted.

RESULTS

Of 280 potentially EVT-eligible patients, 72/129 (56%) telestroke and 91/151 (60%) direct admissions eventually underwent EVT (age 76 (66-82) years, median (interquartile range), 46% men, NIHSS score 17 (13-20)). Telestroke patients had larger pre-EVT infarct cores (ASPECTS: 7 (6-8) vs. 8 (7-9); p < 0.0001) and shorter door-to-groin puncture times (71 (56-84) vs. 101 (79-133) min; p < 0.0001) than directly admitted patients. sICH (2.8% vs. 1.1%; p = 0.58), successful reperfusion (81% vs. 77%; p = 0.56), 90-day favourable outcome (25% vs. 29%; p = 0.65) and 90-day survival (73% vs. 67%; p = 0.39) rates were comparable among telestroke and direct admissions.

DISCUSSION

Our data underpins the important role of telemedicine in identifying acute ischaemic stroke patients lacking immediate access to EVT-capable stroke centres. Stroke patients selected via telemedicine and those directly admitted had comparable chances of favourable outcomes after EVT for large vessel occlusion.

Endovascular Thrombectomy in Acute Ischemic Stroke

Despite several effective strategies of stroke prevention, the stroke epidemic still constitutes the leading cause of permanent disability. The recent series of well-designed, convincingly-positive randomized controlled trials of endovascular thrombectomy in stroke patients with large vessel occlusion launched a paradigm shift and a new era in acute stroke management. The present review provides an overview of the technical aspects of the procedure, discusses patient selection criteria, summarizes the current evidence from randomized trials about its efficacy and safety, and explores its implications in the organization of acute stroke care.

Frequency of early rapid improvement in stroke severity during interfacility transfer

Background

As interfacility transfer of patients with stroke becomes increasingly common, understanding fluctuations in deficits during transfer may help predict resource needs. We sought to characterize changes in NIH Stroke Scale (NIHSS) scores during transfer and identify factors associated with early rapid improvement (ERI).

Methods

We used prospectively collected data from our Comprehensive Stroke Center's (CSCs) stroke and telestroke network databases. We calculated changes in NIHSS scores for all patients transferred to our CSC after an initial telestroke evaluation from January 2010 to December 2015. Logistic regression identified factors associated with ERI, controlling for patient characteristics available on arrival.

Results

Among the 505 patients included, the median initial NIHSS score was 11 (interquartile range [IQR] 5-18), and on CSC arrival, it was 9 (IQR 3-17), with a median change of 0 (-3 to -0). Of note, 74.5% of scores changed by fewer than 4 points (7% increased ≥4 points, and 19% decreased ≥4). In 85% of cases, the NIHSS score change did not cross a threshold to alter eligibility for thrombectomy. In multivariable modeling, ERI was associated with ability to ambulate before the index stroke (odds ratio [OR] 5.79, p = 0.02) and higher initial NIHSS (OR 1.06 per point, p = 0.001).

Conclusions

These findings may be valuable for resource planning and for inclusion in thrombectomy alert activation processes at the receiving hospital.

Post-Thrombolysis Recanalization in Stroke Referrals for Thrombectomy

Background and Purpose—

Whether all acute stroke patients with large vessel occlusion need to undergo intravenous thrombolysis before mechanical thrombectomy (MT) is debated as (1) the incidence of post-thrombolysis early recanalization (ER) is still unclear; (2) thrombolysis may be harmful in patients unlikely to recanalize; and, conversely, (3) transfer for MT may be unnecessary in patients highly likely to recanalize. Here, we determined the incidence and predictors of post-thrombolysis ER in patients referred for MT and derive ER prediction scores for trial design.

Methods—

Registries from 4 MT-capable centers gathering patients referred for MT and thrombolyzed either on site (mothership) or in a non MT-capable center (drip-and-ship) after magnetic resonance– or computed tomography–based imaging between 2015 and 2017. ER was identified on either first angiographic run or noninvasive imaging. In the magnetic resonance imaging subsample, thrombus length was determined on T2*-based susceptibility vessel sign. Independent predictors of no-ER were identified using multivariable logistic regression models, and scores were developed according to the magnitude of regression coefficients. Similar registries from 4 additional MT-capable centers were used as validation cohort.

Results—

In the derivation cohort (N=633), ER incidence was ≈20%. In patients with susceptibility vessel sign (n=498), no-ER was independently predicted by long thrombus, proximal occlusion, and mothership paradigm. A 6-point score derived from these variables showed strong discriminative power for no-ER (C statistic, 0.854) and was replicated in the validation cohort (n=353; C statistic, 0.888). A second score derived from the whole sample (including negative T2* or computed tomography–based imaging) also showed good discriminative power and was similarly validated. Highest grades on both scores predicted no-ER with >90% specificity, whereas low grades did not reliably predict ER.

Conclusions—

The substantial ER rate underlines the benefits derived from thrombolysis in bridging populations. Both prediction scores afforded high specificity for no-ER, but not for ER, which has implications for trial design.

Futile inter-hospital transfer for mechanical thrombectomy in a semi-rural context: analysis of a 6-year prospective registry

Background and purpose

Inter-hospital transfer for mechanical thrombectomy (MT) might result in the transfer of patients who finally will not undergo MT (ie, futile transfers [FT]). This study evaluated FT frequency in a primary stroke center (PSC) in a semi-rural area and at 156 km from the comprehensive stroke center (CSC).

Methodology

Retrospective analysis of data collected in a 6-year prospective registry concerning patients admitted to our PSC within 4.5 hours of acute ischemic stroke (AIS) symptom onset, with MR angiography indicating the presence of large vessel occlusion (LVO) without large cerebral infarction (DWI-ASPECT ≥5), and selected for transfer to the CSC to undergo MT. Futile transfer rate and reasons were determined, and the relevant time measures recorded.

Results

Among the 529 patients screened for MT, 278 (52.6%) were transferred to the CSC. Futile transfer rate was 45% (n=125/278) and the three main reasons for FT were: clinical improvement and reperfusion on MRI on arrival at the CSC (58.4% of FT); clinical worsening and/or infarct growth (16.8%); and longer than expected inter-hospital transfer time (11.2%). Predictive factors of FT due to clinical improvement/reperfusion on MRI could not be identified. Baseline higher NIHSS (21 vs 17; P=0.01) and lower DWI-ASPECT score (5 vs 7; P=0.001) were associated with FT due to clinical worsening/infarct growth on MRI.

Conclusions

In our setting, 45% of transfers for MT were futile. None of the baseline factors could predict FT, but the initial symptom severity was associated with FT caused byclinical worsening/infarct growth.

Patterns of Stroke Transfers and Identification of Predictors for Thrombectomy

BACKGROUND

Interhospital transfers for endovascular thrombectomy (EVT) evaluation have increased since the publication of landmark neuroendovascular stroke trials in 2015. The lack of guidelines to select potential EVT candidates prior to transfer can lead to instances where, despite considerable costs and transport risks, transferred patients do not ultimately undergo EVT. Our aim was to characterize the patterns and identify predictors for EVT on transfer.

METHODS

In this observational cohort study, we retrospectively analyzed patients with acute ischemic stroke (AIS) transferred to our institution for EVT evaluation from January 2015 to March 2016. Clinical and radiographic predictors for EVT on transfer were determined with multivariable logistic regression analysis.

RESULTS

A total of 103 transfer patients with AIS were included in the study, and 52% were women. A higher collateral score (P < 0.01), a higher National Institutes of Health Stroke Scale (NIHSS) score (P < 0.01), computed tomography angiography (CTA) at referring hospital (P < 0.01), and large vessel occlusion on arrival CTA (P < 0.01) were significant in patients who underwent EVT on univariable analysis. More than half (61.1%) of transfers were futile and primarily related to absence of large vessel occlusion on arrival. A higher collateral score (P = 0.02), a higher NIHSS score (P = 0.006), and having undergone a CTA at the referring center (P = 0.002) remained the independent predictors of EVT. The C statistic for the model was 0.94.

CONCLUSIONS

A higher collateral score, the acquisition of CTA imaging at the referring centers, and a higher NIHSS score independently predicted EVT on transfer.

Association of Clinical, Imaging, and Thrombus Characteristics With Recanalization of Visible Intracranial Occlusion in Patients With Acute Ischemic Stroke

IMPORTANCE

Recanalization of intracranial thrombus is associated with improved clinical outcome in patients with acute ischemic stroke. The association of intravenous alteplase treatment and thrombus characteristics with recanalization over time is important for stroke triage and future trial design.

OBJECTIVE

To examine recanalization over time across a range of intracranial thrombus occlusion sites and clinical and imaging characteristics in patients with ischemic stroke treated with intravenous alteplase or not treated with alteplase.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter prospective cohort study of 575 patients from 12 centers (in Canada, Spain, South Korea, the Czech Republic, and Turkey) with acute ischemic stroke and intracranial arterial occlusion demonstrated on computed tomographic angiography (CTA).

EXPOSURES

Demographics, clinical characteristics, time from alteplase to recanalization, and intracranial thrombus characteristics (location and permeability) defined on CTA.

MAIN OUTCOMES AND MEASURES

Recanalization on repeat CTA or on first angiographic acquisition of affected intracranial circulation obtained within 6 hours of baseline CTA, defined using the revised arterial occlusion scale (rAOL) (scores from 0 [primary occlusive lesion remains the same] to 3 [complete revascularization of primary occlusion]).

RESULTS

Among 575 patients (median age, 72 years [IQR, 63-80]; 51.5% men; median time from patient last known well to baseline CTA of 114 minutes [IQR, 74-180]), 275 patients (47.8%) received intravenous alteplase only, 195 (33.9%) received intravenous alteplase plus endovascular thrombectomy, 48 (8.3%) received endovascular thrombectomy alone, and 57 (9.9%) received conservative treatment. Median time from baseline CTA to recanalization assessment was 158 minutes (IQR, 79-268); median time from intravenous alteplase start to recanalization assessment was 132.5 minutes (IQR, 62-238). Successful recanalization occurred at an unadjusted rate of 27.3% (157/575) overall, including in 30.4% (143/470) of patients who received intravenous alteplase and 13.3% (14/105) who did not (difference, 17.1% [95% CI, 10.2%-25.8%]). Among patients receiving alteplase, the following factors were associated with recanalization: time from treatment start to recanalization assessment (OR, 1.28 for every 30-minute increase in time [95% CI, 1.18-1.38]), more distal thrombus location, eg, distal M1 middle cerebral artery (39/84 [46.4%]) vs internal carotid artery (10/92 [10.9%]) (OR, 5.61 [95% CI, 2.38-13.26]), and higher residual flow (thrombus permeability) grade, eg, hairline streak (30/45 [66.7%]) vs none (91/377 [24.1%]) (OR, 7.03 [95% CI, 3.32-14.87]).

CONCLUSIONS AND RELEVANCE

In patients with acute ischemic stroke, more distal thrombus location, greater thrombus permeability, and longer time to recanalization assessment were associated with recanalization of arterial occlusion after administration of intravenous alteplase; among patients who did not receive alteplase, rates of arterial recanalization were low. These findings may help inform treatment and triage decisions in patients with acute ischemic stroke.

Interfacility transfers for US ischemic stroke and TIA, 2006-2014

OBJECTIVE

To investigate changes in emergency department (ED) transfers for ischemic stroke (IS) and TIA.

METHODS

We performed a retrospective observational study using the US Nationwide Emergency Department Sample to identify changes in interfacility ED transfers for IS and TIA from the perspective of the transferring ED (2006-2014). We calculated nationwide transfer rates and individual ED transfer rates for IS/TIA by diagnosis and hospital characteristics. Hospital-level fractional logistic regression examined changes in transfer rates over time.

RESULTS

The population-estimated number of transfers for IS/TIA increased from 22,576 patient visits in 2006 to 54,485 patient visits in 2014 (p trend < 0.001). The rate of IS/TIA transfer increased from 3.4 (95% confidence interval [CI] 3.0-3.8) in 2006 to 7.6 (95% CI 7.2-7.9) in 2014 per 100 ED visits. Among individual EDs, mean transfer rates for IS/TIA increased from 8.2 per 100 ED visits (median 2.0, interquartile range [IQR] 0-10.2) to 19.4 per 100 ED visits (median 8.1, IQR 1.1-33.3) (2006-2014) (p trend < 0.001). Transfers were more common among IS. Transfer rates were greatest among rural (adjusted odds ratio [AOR] 3.05, 95% CI 2.56-3.64) vs urban/teaching and low-volume EDs (AOR 7.49, 95% CI 6.58-8.53, 1st vs 4th quartile). The adjusted odds of transfer for IS/TIA increased threefold (2006-2014).

CONCLUSIONS

Interfacility ED transfers for IS/TIA more than doubled from 2006 to 2014. Further work should determine the necessity of IS/TIA transfers and seek to optimize the US stroke care system.

Primary to comprehensive stroke center transfers: Appropriateness, not futility

Background and purpose

Ischemic stroke patients must be transferred to comprehensive stroke centers for endovascular treatment, but this transfer can be interpreted post hoc as “futile” if patients do not ultimately undergo the procedure or have a poor outcome. We posit that transfer decisions must instead be evaluated in terms of appropriateness at the time of decision-making.

Methods

We propose a classification schema for Appropriateness of Transfer for Endovascular Thrombectomy based on patient, logistic, and center characteristics.

Results

The classification outline characteristics of patients that are 1. Appropriate for transfer for endovascular treatment; 2. Inappropriate for transfer; and 3. Appropriate for transfer for higher level of care.

Conclusions

Appropriate transfer decisions for endovascular treatment are significant for patient outcomes. A more nuanced understanding of transfer decision-making and a classification for such transfers can help minimize inappropriate transfers in acute stroke.

Modeling the Impact of Interhospital Transfer Network Design on Stroke Outcomes in a Large City

BACKGROUND AND PURPOSE

We sought to model the effects of interhospital transfer network design on endovascular therapy eligibility and clinical outcomes of stroke because of large-vessel occlusion for the residents of a large city.

METHODS

We modeled 3 transfer network designs for New York City. In model A, patients were transferred from spoke hospitals to the closest hub hospitals with endovascular capabilities irrespective of hospital affiliation. In model B, which was considered the base case, patients were transferred to the closest affiliated hub hospitals. In model C, patients were transferred to the closest affiliated hospitals, and transfer times were adjusted to reflect full implementation of streamlined transfer protocols. Using Monte Carlo methods, we simulated the distributions of endovascular therapy eligibility and good functional outcomes (modified Rankin Scale score, 0-2) in these models.

RESULTS

In our models, 200 patients (interquartile range [IQR], 168-227) with a stroke amenable to endovascular therapy present to New York City spoke hospitals each year. Transferring patients to the closest hub hospital irrespective of affiliation (model A) resulted in 4 (IQR, 1-9) additional patients being eligible for endovascular therapy and an additional 1 (IQR, 0-2) patient achieving functional independence. Transferring patients only to affiliated hospitals while simulating full implementation of streamlined transfer protocols (model C) resulted in 17 (IQR, 3-41) additional patients being eligible for endovascular therapy and 3 (IQR, 1-8) additional patients achieving functional independence.

CONCLUSIONS

Optimizing acute stroke transfer networks resulted in clinically small changes in population-level stroke outcomes in a dense, urban area.

Mechanical thrombectomy in orally anticoagulated patients with acute ischemic stroke

BACKGROUND AND PURPOSE

To investigate the efficacy and safety of mechanical thrombectomy in patients with acute ischemic stroke according to the oral anticoagulation medication taken at the time of stroke onset.

MATERIALS AND METHODS

A retrospective multicenter study of prospectively collected data based on data from the registry the Madrid Stroke Network was performed. We included consecutive patients with acute ischemic stroke treated with mechanical thrombectomy and compared the frequency of intracranial hemorrhage and the modified Rankin Scale (mRS) score at 3 months according to anticoagulation status.

RESULTS

The study population comprised 502 patients, of whom 389 (77.5%) were not anticoagulated, 104 (20.7%) were taking vitamin K antagonists, and 9 (1.8%) were taking direct oral anticoagulants. Intravenous thrombolysis had been performed in 59.8% and 15.0% of non-anticoagulated and anticoagulated patients, respectively. Rates of intracranial hemorrhage after treatment were similar between non-anticoagulated and anticoagulated patients, as were rates of recanalization. After 3 months of follow-up, the mRS score was ≤2 in 56.3% and 55.7% of non-anticoagulated and anticoagulated patients, respectively (P=NS). Mortality rates were similar in the two groups (13.1%and12.4%, respectively). Among anticoagulated patients, no differences were found for intracranial bleeding, mRS score, or mortality rates between patients taking vitamin K antagonists and those taking direct oral anticoagulants.

CONCLUSIONS

Mechanical thrombectomy is feasible in anticoagulated patients with acute ischemic stroke. The outcomes and safety profile are similar to those of patients with no prior anticoagulation therapy.

Clinical Imaging Factors Associated With Infarct Progression in Patients With Ischemic Stroke During Transfer for Mechanical Thrombectomy

Importance

When transferred from a referring hospital (RH) to a thrombectomy-capable stroke center (TCSC), patients with initially favorable imaging profiles (Alberta Stroke Program Early CT Score [ASPECTS] ≥6) often demonstrate infarct progression significant enough to make them ineligible for mechanical thrombectomy at arrival. In rapidly evolving stroke care networks, the question of the need for vascular imaging at the RHs remains unsolved, resulting in an important amount of futile transfers for thrombectomy.

Objective

To examine the clinical imaging factors associated with unfavorable imaging profile evolution for thrombectomy in patients with ischemic stroke initially transferred to non-TCSCs.

Design, Setting, and Participants

Data from patients transferred from 1 of 30 RHs in our regional stroke network and presenting at our TCSC from January 1, 2010, to January 1, 2016, were retrospectively analyzed. Consecutive patients with acute ischemic stroke initially admitted to a non-thrombectomy-capable RH and transferred to our center for which a RH computed tomography (CT) and a CT angiography (CTA) at arrival were available for review.

Main Outcomes and Measures

ASPECTS were evaluated. The adequacy of leptomeningeal collateral blood flow was rated as no or poor, decreased, adequate, or augmented per the adapted Maas scale. The main outcome was an ASPECTS decay, defined as an initial ASPECTS of 6 or higher worsening between RH and TCSC CTs to a score of less than 6 (making the patient less likely to derive clinical benefit from thrombectomy at arrival).

Results

A total of 316 patients were included in the analysis (mean [SD] age, 70.3 [14.2] years; 137 [43.4%] female). In multivariable models, higher National Institutes of Health Stroke Score, lower baseline ASPECTSs, and no or poor collateral blood vessel status were associated with ASPECTS decay, with collateral blood vessel status demonstrating the highest adjusted odds ratio of 5.14 (95% CI, 2.20-12.70; P < .001). Similar results were found after stratification by vessel occlusion level.

Conclusions and Relevance

In patients with ischemic stroke transferred for thrombectomy, poor collateral blood flow and stroke clinical severity are the main determinants of ASPECTS decay. Our findings suggest that in certain subgroups vascular imaging, including collateral assessment, can play a crucial role in determining the benefits of transfer for thrombectomy.