National Trends and Outcomes of Hospital Presentation Mode for Endovascular Stroke Treatment in the U.S.

BACKGROUND: The optimal triage strategy for patients suspected of acute ischemic stroke due to large vessel occlusion (LVO) remains debated. We explored trends in presentation mode and their outcomes for mechanical thrombectomy (MT) hospitalizations based on the National Inpatient Sample (NIS) database. METHODS: We retrospectively explored the NIS database from 2016 to 2020 for stroke hospitalizations with MT. We compared outcomes at discharge for MT hospitalizations with direct vs. transferred presentation. Outcomes comprised favorable discharge disposition (home without assistance), in-hospital mortality, and radiographic intracranial hemorrhage (ICH). RESULTS: This study included 100,865 patients undergoing MT, of whom 32,685 patients (32.4%) were transferred (median age 71[60-81] years, 16775(51.2%) women). The utilization of MT in the U.S. nearly doubled during the study period, whereas the proportion of in-hospital transfers for MT remained unchanged (32.1-33.2%). White race, higher presenting NIHSS, hospital size, status, and location were independent predictors of transferred status. Transferred status was significantly associated with a lower likelihood of achieving favorable outcome (OR:0.80,95% CI: [0.72,0.89],P<0.001) and a higher likelihood of ICH (OR:1.18, 95% CI:[1.07,1.31],P=0.001), whereas no association was observed between presentation mode and in-hospital mortality (OR:1.07,95% CI:[0.93,1.23],P=0.33). CONCLUSION: Patients with direct presentation for MT after a stroke had better discharge outcomes and a lower risk of hemorrhagic transformation compared to those who were transferred from another facility. Determining the optimal triage strategy for MT following LVO stroke is an insightful area for future clinical trials.

Mothership versus Drip-and-Ship for stroke in a rural area: A French prospective observational study.

BACKGROUND: The availability of mechanical thrombectomy (MT) is limited. Thus, there are two paradigms for patients living closer to a primary stroke center (PSC) than a comprehensive stroke center (CSC) capable of MT: "Mothership" (direct referral to a CSC) and "Drip-and-Ship" (referral to a PSC for imaging and thrombolysis and transfer to a CSC for thrombectomy or monitoring). We aimed to compare the prognosis of patients at three months between the two paradigms in a rural area. MATERIALS: From September 2019 to March 2021, we prospectively included patients living closer to a PSC than the one CSC, regardless of the type of stroke or reperfusion treatment. The proportion of patients with a good functional outcome (Rankin≤2) at three months was compared between the two initial orientations for all patients and for subgroups: patients with ischemic stroke and patients treated by MT. RESULTS: Among the 206 patients included, 103 were admitted directly to the CSC (82.5% had an ischemic stroke and 24.3% a MT) and 103 initially admitted to a PSC and then transferred to the CSC (100% had an ischemic stroke and 52.4% a MT). The proportion of patients with a good outcome was comparable between the two groups (54.5% vs. 43.7%, P=0.22). Among the 79 patients who underwent MT, the prognosis at three months was better in the Mothership group (49.3% vs. 15.3%, P=0.01). CONCLUSION: The functional prognosis is comparable between Mothership and Drip-and-Ship paradigms in our setting, despite a trend towards a better prognosis for the Mothership. As has been shown in urban settings, the mothership paradigm also leads to a better prognosis for patients treated with MT in a rural setting.

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.

From mothership to drip-and-ship: Effects of staff shortages at a comprehensive stroke center.

BACKGROUND: Mechanical thrombectomy (MT) has been shown to be effective in the acute phase of ischemic stroke. Current data suggests that the drip-and-ship and mothership telestroke models are equally effective for its administration. We describe the consequences of changing the telestroke model due to staff shortages in a comprehensive stroke center (Besançon), which was replaced by a more distant one (Dijon). METHODS: We conducted a retrospective analysis of all patients referred for MT from January 2015 to December 2018. We analyzed the time between symptom onset and arrival in the angiography suite. We also calculated number of thrombectomies divided by number of days on call, and rate of thrombectomies relative to the number of strokes in each group. RESULTS: In Besançon, 205 patients underwent an MT procedure, versus 43 patients in Dijon. A further four patients were transferred to Dijon but not treated. The time from symptom onset to arrival in the angiography suite was longer for Dijon; 334min versus 281min for Besançon (p<0.001). The percentage of thrombectomies performed per day on call was higher for Besançon: 18.6% versus 13.2% in Dijon (p=0.026). CONCLUSIONS: Over the study period, the time from symptom onset to angiography suite was longer for patients who were transferred to Dijon. The period in which the Besançon hospital experienced the greatest lack of personnel corresponded to a decrease in the number of MTs performed.

Optimal patient protocols in regional acute stroke care.

In acute stroke care two proven reperfusion treatments exist: (1) a blood thinner and (2) an interventional procedure. The interventional procedure can only be given in a stroke centre with specialized facilities. Rapid initiation of either is key to improving the functional outcome (often emphasized by the common phrase in acute stroke care "time=brain"). Delays between the moment the ambulance is called and the initiation of one or both reperfusion treatment(s) should therefore be as short as possible. The speed of the process strongly depends on five factors: patient location, regional patient allocation by emergency medical services (EMS), travel times of EMS, treatment locations, and in-hospital delays. Regional patient allocation by EMS and treatment locations are sub-optimally configured in daily practice. Our aim is to construct a mathematical model for the joint decision of treatment locations and allocation of acute stroke patients in a region, such that the time until treatment is minimized. We describe acute stroke care as a multi-flow two-level hierarchical facility location problem and the model is formulated as a mixed integer linear program. The objective of the model is the minimization of the total time until treatment in a region and it incorporates volume-dependent in-hospital delays. The resulting model is used to gain insight in the performance of practically oriented patient allocation protocols, used by EMS. We observe that the protocol of directly driving to the nearest stroke centre with special facilities (i.e., the mothership protocol) performs closest to optimal, with an average total time delay that is 3.9% above optimal. Driving to the nearest regional stroke centre (i.e., the drip-and-ship protocol) is on average 8.6% worse than optimal. However, drip-and-ship performs better than the mothership protocol in rural areas and when a small fraction of the population (at most 30%) requires the second procedure, assuming sufficient patient volumes per stroke centre. In the experiments, the time until treatment using the optimal model is reduced by at most 18.9 minutes per treated patient. In economical terms, assuming 150 interventional procedures per year, the value of medical intervention in acute stroke can be improved upon up to € 1,800,000 per year.

Direct admission vs. secondary transfer for mechanical thrombectomy: long-term clinical outcomes from a single Polish Comprehensive Stroke Centre.

INTRODUCTION: We aimed to compare 3-month clinical outcomes after mechanical thrombectomy (MT) in patients transferred directly to a comprehensive stroke centre ('mothership', MS) to the outcomes of patients transferred secondarily from primary stroke centres ('drip-and-ship', DAS) in Lubelskie province, the third largest province in Poland. MATERIAL AND METHODS: In a prospective stroke registry, all patients with large vessel occlusion in anterior circulation admitted within six hours of onset and treated with MT between 2017 and 2020 were retrospectively analysed. RESULTS: A total of 400 patients was evaluated: 267 treated with the MS approach and 133 with the DAS approach. Time from stroke onset to groin puncture was shorter in the MS group. There was a significant difference in 3-month excellent clinical outcomes (mRS 0-1) between these two groups (32.9% of MS patients vs. 22.5% of DAS patients, p < 0.05), but there was no difference if the 3-month endpoint was expressed as mRS ≤ 2 (42.3% of MS vs. 34.5% of DAS patients, p = 0.13). The rate of symptomatic intracranial haemorrhage and mortality was comparable in both groups. CONCLUSIONS: Our study shows that direct admission to a comprehensive stroke centre resulted in more patients achieving excellent treatment outcomes (mRS 0-1). At the same time, the superiority of the MT model over the DAS model in obtaining mRS 0-2 was not unequivocally demonstrated. Further studies are needed to determine the best stroke model for patients potentially eligible for MT.

Outcomes of thrombolytic therapy in acute ischemic stroke: mothership, drip-and-ship, and ship-and-drip paradigms.

BACKGROUND: Chulalongkorn Stroke Center is a comprehensive stroke center (CSC) located in Bangkok, Thailand. Our stroke network consists of different levels of spoke hospitals, ranging from community hospitals where thrombolytic treatment is not available, to those capable of onsite thrombolytic therapy. This study aimed to assess the time to treatment and outcomes among acute ischemic stroke patients who received thrombolytic treatment in the Chulalongkorn Stroke Network by 1.) Direct arrival at the CSC (mothership) 2.) Telestroke-assisted thrombolytic treatment with secondary transfer to the CSC (drip-and-ship) 3.) Referral from community hospital to the CSC for thrombolytic treatment (ship-and-drip). METHODS: Acute ischemic stroke patients who received thrombolytic treatment during January 2016-December 2017 in the Chulalongkorn Stroke Network were studied. Time to treatment and clinical outcomes were compared among treatment groups. RESULTS: There were 273 patients in the study including 147, 87, and 39 patients in mothership, drip-and-ship, and ship-and-drip paradigms, respectively. The door-to-needle-time (DTN) and onset-to-needle-time (OTN) times were significantly longest in ship-and-drip group (146.5 ± 62/205.03 ± 44.88 mins) compared to mothership (38 ± 23/155.2 ± 60.54 mins) and drip-and-ship (63.0 ± 44/166.09 ± 87 mins), P < 0.05. There was no significant difference regarding functional independence defined by modified Rankin Scale (mRS) ≤ 2 at 3 months (P = 0.12), in-hospital mortality (P = 0.37), mortality at 3 months (P = 0.73), and symptomatic intracerebral hemorrhage (P = 0.24) among groups. CONCLUSION: Thrombolytic treatment with drip and ship method under teleconsultation is feasible in Thailand. There was no difference of clinical outcome among the 3 treatment paradigms. However, DTN time and OTN time were longest in the ship-and-drip paradigm.

[Intravenous lysis treatment in acute stroke treatment-latest situation]. / Intravenöse Lysetherapie zur akuten Schlaganfalltherapie ­ neuester Stand.

CLINICAL ISSUE: Intravenous (i.v.) thrombolysis and mechanical thrombectomy are two essential pillars of acute stroke treatment in patients with vascular occlusion in the anterior circulation. The issue about using so-called bridging thrombolysis in acute stroke patients is increasingly under discussion. RESULTS: After application of i.v. thrombolysis treatment, stroke patients who were primarily transported to a neurovascular center and underwent timely endovascular treatment, showed a lower preinterventional recanalization rate, a lower 90-day mortality but no significant difference in the clinical outcome after 3 months compared with stroke patients with mechanical thrombectomy alone. Higher rates of intracranial hemorrhage could be detected in the bridging thrombolysis group of patients. CONCLUSION: The i.v. thrombolysis treatment is still an essential treatment concept in acute stroke management. Further studies should be carried out with respect to the application in mothership stroke patients undergoing early endovascular treatment.

[Prehospital management of acute stroke : Using the example of Saarland ambulance services]. / Prähospitalphase der Schlaganfallversorgung : Am Beispiel des saarländischen Rettungsdienstes.

BACKGROUND: The preclinical care strategy was changed after reevaluation of endovascular thrombectomy in the S2k guideline of the German Neurological Society (DGN). Severe strokes should be directly transferred to neurovascular centers (model "mothership"). The severity of a stroke should be determined using the LAMS (Los Angeles Motor Scale) score. MATERIALS AND METHODS: The general conditions of preclinical care of patients with stroke in the Saarland are presented. The key figures and statistical data of clinic assignments in the adapted care strategy are evaluated. RESULTS: The 2018 data from the Saarland Ambulance Services indicate that 9.1% of all preclinical emergencies are diagnosed with "transient ischemic attack (TIA)/insult/bleeding"; 97.1% of these patients were admitted to one of the 10 hospitals in Saarland with a stroke unit. A care time at the emergency site of 20 min was observed in 78.2%, a prehospital time of 60 min in 90.1% of the missions. Preclinically, severe strokes with LAMS score ≥4 were detected in 19.2% of all stroke patients; 71.6% of these severe strokes were assigned to one of two neurovascular centers in the Saarland. CONCLUSIONS: With good traffic and hospital infrastructure in Saarland, severe strokes can be treated primarily in neurovascular centers. Differentiated care requirements with monitoring of key figures in medical quality management and clear agreements with the target hospitals in the implementation of a common care strategy are essential.

Clinical outcomes after endovascular thrombectomy in different triage methods.

Objective: The purpose of this study was to evaluate the effectiveness and safety of drip and ship (DS) for acute ischemic stroke (AIS) by comparing three treatment strategies: 1) patients seen at a primary stroke center, started on emergency intravenous thrombolysis and then transported to a comprehensive stroke center (drip and ship, DS); 2) patients immediately transferred to comprehensive stroke center without starting intravenous thrombolysis, for mechanical thrombectomy (non-drip and ship, non-DS); and 3) patients admitted directly to the comprehensive stroke center for assessment and subsequent bridging thrombolysis (mothership, MS). Methods: We retrospectively reviewed the data of patients that underwent mechanical thrombectomy for AIS from November 2020 to May 2022 at our institution. Patients were divided into three groups: DS, non-DS, and MS. Time course, multimodal CT features and clinical results were compared among the three groups. Results: The study included 62 patients, with 19, 18, and 25 patients in DS, non-DS, and MS groups, respectively. Baseline characteristics did not differ among the three groups. The DS group had a significantly longer median onset to groin time than the MS group (395 min vs 244 min; P < 0.001), a significantly shorter onset to primary stroke center time than the non-DS group (90 min vs 463 min; P < 0.001), and a longer primary stroke center to groin puncture time than the non-DS group (277 min vs 162 min; P = 0.002). The onset to needle time was longer in the MS group than the DS group (151.2 min vs 111.8 min; P = 0.041). The intravenous thrombolysis to puncture time was shorter in the MS group compared with DS (56 min vs 278 min; P < 0.001). No significant differences were present among groups in post-operative variables measured. Conclusions: DS is a safe and effective method, with no increased risk of postoperative complications or death compared to non-DS and MS methods. The study provides a reference for the selection of transport modes for AIS patients.

Mothership vs. drip-and-ship: evaluation of initial treatment strategies for acute ischemic stroke in a well-developed network of specialized hospitals.

PURPOSE: Two strategies of initial patient care exist in endovascular thrombectomy (ET) depending on the site of initial admission: the mothership (MS) and drip-and-ship (DnS) principles. This study compares both strategies in regard to patient outcome in a local network of specialized hospitals. METHODS: Two-hundred-and-two patients undergoing ET in anterior circulation ischemic stroke between June 2016 and May 2018 were enrolled. Ninety two patients were directly admitted to our local facility (MS), One-hundred-and-ten were secondarily referred to our facility. Group comparisons between admission strategies in three-months modified Rankin Scale (mRS), Maas Score and Alberta-Stroke-Program-Early-computed-tomography-score (ASPECTS), National-Institutes-of-Health-Stroke-Scale (NIHSS), age and onset-to-recanalization-time were performed. Correlation between admission strategy and mRS was calculated. A binary logistic regression model was computed including mRS as dependent variable. RESULTS: There were neither significant group differences in three-months mRS between MS and DnS nor significant correlations. Patients tended to achieve a better outcome with DnS. Collateralization status differed between MS and DnS (p = 0.003) with better collateralization in DnS. There were no significant group differences in NIHSS or ASPECTS but in onset-to-recanalization-time (p < 0.001) between MS and DnS. Binary logistic regression showed a high explanation of variance of mRS but no significant results for admission strategy. CONCLUSIONS: Functional outcome in patients treated with ET is comparable between the MS and DnS principles. Tendentially better outcome in the DnS subgroup may be explained by selection bias due to a higher willingness to apply ET in patients with worse baseline conditions (e.g. worse collateralization), if patients undergoing MS are already on site.

Geographical Requirements for the Applicability of the Results of the RACECAT Study to Other Stroke Networks.

Background The RACECAT (Transfer to the Closest Local Stroke Center vs Direct Transfer to Endovascular Stroke Center of Acute Stroke Patients With Suspected Large Vessel Occlusion in the Catalan Territory) trial was the first randomized trial addressing the prehospital triage of acute stroke patients based on the distribution of thrombolysis centers and intervention centers in Catalonia, Spain. The study compared the drip-and-ship with the mothership paradigm in regions where a local thrombolysis center can be reached faster than the nearest intervention center (equipoise region). The present study aims to determine the population-based applicability of the results of the RACECAT study to 4 stroke networks with a different degree of clustering of the intervention centers (clustered, dispersed). Methods and Results Stroke networks were compared with regard to transport time saved for thrombolysis (under the drip-and-ship approach) and transport time saved for endovascular therapy (under the mothership approach). Population-based transport times were modeled with a local instance of an openrouteservice server using open data from OpenStreetMap.The fraction of the population in the equipoise region differed substantially between clustered networks (Catalonia, 63.4%; France North, 87.7%) and dispersed networks (Southwest Bavaria, 40.1%; Switzerland, 40.0%). Transport time savings for thrombolysis under the drip-and-ship approach were more marked in clustered networks (Catalonia, 29 minutes; France North, 27 minutes) than in dispersed networks (Southwest Bavaria and Switzerland, both 18 minutes). Conclusions Infrastructure differences between stroke networks may hamper the applicability of the results of the RACECAT study to other stroke networks with a different distribution of intervention centers. Stroke networks should assess the population densities and hospital type/distribution in the temporal domain before applying prehospital triage algorithms to their specific setting.

Comparison of mothership versus drip-and-ship models in treating patients with acute ischemic stroke: A systematic review and meta-analysis.

INTRODUCTION: There is controversy if direct to comprehensive center "mothership" or stopping at primary center for thrombolysis before transfer to comprehensive center "drip-and-ship" are best models of treatment of acute stroke. In this study, we compare mothership and drip-and-ship models to evaluate the best option of functional outcome. METHODS: Studies between 1990 and 2020 were extracted from online electronic databases. Clinical outcomes, critical time measurements, functional independence, and mortality were then compared. RESULTS: A total of 7824 patients' data were retrieved from 13 publications (3 randomized control trials and 10 retrospective ones). In addition, 4639 (59.3%) patients were treated under mothership model, and 3185 (40.7%) followed the drip-and-ship model with mean age of 70.01 ± 3.58 versus 69.03 ± 3.36; p < 0.001, respectively. The National Institute Health Stroke Scale was 15.57 ± 3.83 for the mothership and 15.72 ± 2.99 for the drip-and-ship model (p ≤ 0.001). The mean symptoms onset-to-puncture time was significantly shorter in the mothership group compared to the drip-and-ship (159.69 min vs. 223.89 min; p ≤ 0.001, respectively). Moreover, the collected data indicated no significant difference between symptom's onset to intravenous thrombolysis time and stroke onset-to-successful recanalization time (p = 0.205 and p ≤ 0.001, respectively). Patients had significantly worse functional outcome (modified Rankin score) (3-6) at 90 days in the drip-and-ship model (odds ratio (OR): 1.47, 95% confidence interval (CI): 1.13-1.92, p < 0.004) and 1.49-folds higher likelihood of symptomatic intracerebral hemorrhage (OR: 1.49, 95% CI: 1.22-1.81, p < 0.0001) compared to mothership. However, there were no statistically significant difference in terms of mortality (OR: 1.16, 95% CI: 0.87-1.55, p = 0.32) and successful recanalization (OR: 1.12, 95% CI: 0.76-1.65, p = 0.56) between the two models of care. CONCLUSION: Patients in the mothership model have significantly improved functional independence and recovery. Further studies are needed as the data from prospectively randomized studies are not of sufficient quality to make definite recommendations.

Functional Outcome of Endovascular Treatment in Patients With Acute Ischemic Stroke With Large Vessel Occlusion: Mothership Versus Drip-and-Ship Model in a Portuguese Urban Region.

Introduction Endovascular treatment (EVT) with mechanical thrombectomy and acute carotid stenting has become an integral part of the treatment of acute ischemic stroke with large vessel occlusion. Despite being included in the most recent stroke guidelines, only comprehensive centers can offer EVT and thus patients frequently need to be transferred from primary hospitals. We aimed to assess which pre-hospital model of care - direct admission to a comprehensive stroke center (mothership) or transfer to a comprehensive stroke center after the first admission to the nearest hospital (drip-and-ship) - had the most benefit in stroke patients in a Portuguese urban region. Methods We selected patients admitted to a comprehensive stroke center who underwent EVTs between January 2018 and December 2020, in Lisbon, Portugal. We used data from the Safe Implementation of Treatments in Stroke (SITS) International registry on stroke severity, previous modified Rankin Scale (mRS), time from symptom onset to the first admission, time from symptom onset to the procedure, and mRS three months post stroke. We defined an unfavorable outcome as having an mRS >2 at three months post stroke. For patients with previous mRS >2, an unfavorable outcome was defined as any increase in mRS at three months post stroke. Results We analyzed the data of 1154 patients, of which 407 were admitted through a mothership approach and 747 through a drip-and-ship approach. Both groups were similar regarding sociodemographic characteristics, stroke risk factors, previous disability, and stroke severity. Median onset-to-door time was higher (126 vs 110 minutes, p-value=0.002) but onset-to-procedure time was lower (199 vs 339 minutes, p-value<0.001) in the mothership group. The mothership group had a higher proportion of patients with mRS <3 at three months post stroke than the drip-and-ship group (41.3% vs 34.9%, p-value=0.035). Mortality was similar in both groups. A multivariate logistic regression model confirmed a lower probability of unfavorable outcomes with the mothership approach (OR = 0.677, 95% CI 0.514-0.892, p-value=0.006). Surprisingly, onset-to-procedure time did not have an impact on functional outcomes. Conclusion Our findings show that the mothership model results in better functional outcomes for patients with acute ischemic stroke with large vessel occlusion. Further studies are needed to better define patient selection for this strategy and the impact of a mothership model in comprehensive stroke centers.

Can Helicopters Solve the Transport Dilemma for Patients With Symptoms of Large-Vessel Occlusion Stroke in Intermediate Density Areas? A Simulation Model Based on Real Life Data.

Background: This modeling study aimed to determine if helicopters may optimize the transportation of patients with symptoms of large vessel stroke in "intermediate density" areas, such as Denmark, by bringing them directly to the comprehensive stroke center. Methods: We estimated the time for the treatment of patients requiring endovascular therapy or intravenous thrombolysis under four configurations: "drip and ship" with and without helicopter and "bypass" with and without helicopter. Time delays, stroke numbers per municipality, and helicopter dispatches for four helicopter bases from 2019 were obtained from the Danish Stroke and Helicopter Registries. Discrete event simulation (DES) was used to estimate the capacity of the helicopter fleet to meet patient transport requests, given the number of stroke codes per municipality. Results: The median onset-to-needle time at the comprehensive stroke center (CSC) for the bypass model with the helicopter was 115 min [interquartile range (IQR): 108, 124]; the median onset-to-groin time was 157 min (IQR: 150, 166). The median onset-to-needle time at the primary stroke center (PSC) by ground transport was 112 min (IQR: 101, 125) and the median onset-to-groin time when primary transport to the PSC was prioritized was 234 min (IQR: 209, 261).A linear correlation between travel time by ground and the number of patients transported by helicopter (rho = 0.69, p < 0.001) indicated that helicopters are being used to transport more remote patients. DES demonstrated that an increase in helicopter capture zone by 20 min increased the number of rejected patients by only 5%. Conclusions: Our model calculations suggest that using helicopters to transport patients with stroke directly to the CSC in intermediate density areas markedly reduce onset-to-groin time without affecting time to thrombolysis. In this setting, helicopter capacity is not challenged by increasing the capture zone.

Scheduling Diagnostic Testing Kit Deliveries with the Mothership and Drone Routing Problem.

A critical component in the public health response to pandemics is the ability to determine the spread of diseases via diagnostic testing kits. Currently, diagnostic testing kits, treatments, and vaccines for the COVID-19 pandemic have been developed and are being distributed to communities worldwide, but the spread of the disease persists. In conjunction, a strong level of social distancing has been established as one of the most basic and reliable ways to mitigate disease spread. If home testing kits are safely and quickly delivered to a patient, this has the potential to significantly reduce human contact and reduce disease spread before, during, and after diagnosis. This paper proposes a diagnostic testing kit delivery scheduling approach using the Mothership and Drone Routing Problem (MDRP) with one truck and multiple drones. Due to the complexity of solving the MDRP, the problem is decomposed into 1) truck scheduling to carry the drones and 2) drone scheduling for actual delivery. The truck schedule (TS) is optimized first to minimize the total travel distance to cover patients. Then, the drone flight schedule is optimized to minimize the total delivery time. These two steps are repeated until it reaches a solution minimizing the total delivery time for all patients. Heuristic algorithms are developed to further improve the computational time of the proposed model. Experiments are made to show the benefits of the proposed approach compared to the commonly performed face-to-face diagnosis via the drive-through testing sites. The proposed solution method significantly reduced the computation time for solving the optimization model (less than 50 minutes) compared to the exact solution method that took more than 10 hours to reach a 20% optimality gap. A modified basic reproduction rate (i.e., m R 0) is used to compare the performance of the drone-based testing kit delivery method to the face-to-face diagnostic method in reducing disease spread. The results show that our proposed method (m R 0= 0.002) outperformed the face-to-face diagnostic method (m R 0= 0.0153) by reducing m R 0 by 7.5 times.

Stroke network performance during the first COVID-19 pandemic stage: A meta-analysis based on stroke network models.

BACKGROUND: The effect of the COVID pandemic on stroke network performance is unclear, particularly with consideration of drip&ship vs. mothership models. AIMS: We systematically reviewed and meta-analyzed variations in stroke admissions, rate and timing of reperfusion treatments during the first wave COVID pandemic vs. the pre-pandemic timeframe depending on stroke network model adopted. SUMMARY OF FINDINGS: The systematic review followed registered protocol (PROSPERO-CRD42020211535), PRISMA and MOOSE guidelines. We searched MEDLINE, EMBASE, and CENTRAL until 9 October 2020 for studies reporting variations in ischemic stroke admissions, treatment rates, and timing in COVID (first wave) vs. control-period. Primary outcome was the weekly admission incidence rate ratio (IRR = admissions during COVID-period/admissions during control-period). Secondary outcomes were (i) changes in rate of reperfusion treatments and (ii) time metrics for pre- and in-hospital phase. Data were pooled using random-effects models, comparing mothership vs. drip&ship model. Overall, 29 studies were included in quantitative synthesis (n = 212,960). COVID-period was associated with a significant reduction in stroke admission rates (IRR = 0.69, 95%CI = 0.61-0.79), with higher relative presentation of large vessel occlusion (risk ratio (RR) = 1.62, 95% confidence interval (CI) = 1.24-2.12). Proportions of patients treated with endovascular treatment increased (RR = 1.14, 95%CI = 1.02-1.28). Intravenous thrombolysis decreased overall (IRR = 0.72, 95%CI = 0.54-0.96) but not in the mothership model (IRR = 0.81, 95%CI = 0.43-1.52). Onset-to-door time was longer for the drip&ship in COVID-period compared to the control-period (+32 min, 95%CI = 0-64). Door-to-scan was longer in COVID-period (+5 min, 95%CI = 2-7). Door-to-needle and door-to-groin were similar in COVID-period and control-period. CONCLUSIONS: Despite a 35% drop in stroke admissions during the first pandemic wave, proportions of patients receiving reperfusion and time-metrics were not inferior to control-period. Mothership preserved the weekly rate of intravenous thrombolysis and the onset-to-door timing to pre-pandemic standards.

Quality assurance data for regional drip-and-ship strategies- gearing up the transfer process.

BACKGROUND: Stroke patients with large vessel occlusion (LVO) require endovascular therapy (EVT) provided by comprehensive stroke centers (CSC). One strategy to achieve fast stroke symptom 'onset to treatment' times (OTT) is the preclinical selection of patients with severe stroke for direct transport to CSC. Another is the optimization of interhospital transfer workflow. Our aim was to investigate the dynamics of the OTT of 'drip-and-ship' patients as well as the current 'door-in-door-out' time (DIDO) and its determinants at representative regional German stroke units. METHODS: We determined the numbers of all EVT treatments, 'drip-and-ship' and 'direct-to-center' patients and their median OTT from the mandatory quality assurance registry of the federal state of Hesse, Germany (2012-2019). Additionally, we captured process time stamps from primary stroke centers (PSC) in a consecutive registry of patients referred for EVT in our regional stroke network over a 3 months period. RESULTS: Along with an increase of the EVT rate, the proportion of drip-and-ship patients grew steadily from 19.4% in 2012 to 31.3% in 2019. The time discrepancy for the median OTT between 'drip-and-ship' and 'direct-to-center' patients continuously declined from 173 to 74 min. The largest share of the DIDO (median 92, IQR 69-110) is spent with the organization of EVT and consecutive patient transfer. CONCLUSIONS: 'Drip-and-ship' patients are an important and growing proportion of stroke patients undergoing EVT. The discrepancy in OTT for EVT between 'drip-and-ship' and 'direct-to-center' patients has been reduced considerably. Further optimization of the DIDO primarily aiming at the processes after the detection of LVO is urgently needed to improve stroke patient care.

Drip-and-Ship for Thrombectomy Treatment in Patients With Acute Ischemic Stroke Leads to Inferior Clinical Outcomes in a Stroke Network Covering Vast Rural Areas Compared to Direct Admission to a Comprehensive Stroke Center.

Introduction: Organizing regional stroke care considering thrombolysis as well as mechanical thrombectomy (MTE) remains challenging in light of a wide range of regional population distribution. To compare outcomes of patients in a stroke network covering vast rural areas in southwestern Germany who underwent MTE via direct admission to a single comprehensive stroke center [CSC; mothership (MS)] with those of patients transferred from primary stroke centers [PSCs; drip-and-ship (DS)], we undertook this analysis of consecutive stroke patients with MTE. Materials and Methods: Patients who underwent MTE at the CSC between January 2013 and December 2016 were included in the analysis. The primary outcome measure was 90-day functional independence [modified Rankin score (mRS) 0-2]. Secondary outcome measures included time from stroke onset to recanalization/end of MTE, angiographic outcomes, and mortality rates. Results: Three hundred and thirty-two consecutive patients were included (MS 222 and DS 110). Median age was 74 in both arms of the study, and there was no significant difference in baseline National Institutes of Health Stroke Scale scores (median MS 15 vs. 16 DS). Intravenous (IV) thrombolysis (IVT) rates differed significantly (55% MS vs. 70% DS, p = 0.008). Time from stroke onset to recanalization/end of MTE was 112 min shorter in the MS group (median 230 vs. 342 min, p < 0.001). Successful recanalization [thrombolysis in cerebral infarction (TICI) 2b-3] was achieved in 72% of patients in the MS group and 73% in the DS group. There was a significant difference in 90-day functional independence (37% MS vs. 24% DS, p = 0.017), whereas no significant differences were observed for mortality rates at 90 days (MS 22% vs. DS 17%, p = 0.306). Discussion: Our data suggest that patients who had an acute ischemic stroke admitted directly to a CSC may have better 90-day outcomes than those transferred secondarily for thrombectomy from a PSC.