Saver, Jeffrey L.

Background: A vast amount of literature is available on the burden of acute ischemic stroke (AIS). Yet, most information on AIS burden does not stratify by stroke severity, and the inclusion of mild strokes (National Institute of Health Stroke Scale < 5) might obscure the true impact of moderate-to-severe AIS. Therefore, it is important to understand the literature as it pertains to the epidemiological, clinical, humanistic, and economic burden of moderate-to-severe AIS from a global perspective. Methods: A systematic literature review (SLR) was conducted, including articles published between January 2015 and June 2023. The clinical burden search focused on patients with moderate or severe AIS. Due to the paucity of evidence, the humanistic and economic burdens were evaluated based on overall AIS studies. Abstract and full-text screening were conducted by 2 reviewers, with data extraction completed by 1 reviewer. In all, 136 studies were included in the SLR. Results: AIS caused a substantial burden for patients and the healthcare system. The clinical burden of AIS (specifically severe AIS) resulted in high mortality and worse functional outcomes across multiple demographics (female sex, older age, and patients with comorbidities). The economic burden of overall AIS was substantial, with inpatient costs as the primary driver (a mean or median stay of 7 days). The highest inpatient costs were reported in South Korea ($45,180) and the United States ($38,470). Conclusions: The review highlighted the huge burden of moderate-to-severe AIS, with patients experiencing worse outcomes with increased stroke severity. Further focus is needed on outcomes relating to moderate-to-severe AIS to fully understand the burden of stroke in this patient population.

Background: Despite the well-established potent benefit of mechanical thrombectomy (MT) for large vessel occlusion (LVO) stroke, access to MT has not been studied globally. We conducted a worldwide survey of countries on 6 continents to define MT access (MTA), the disparities in MTA, and its determinants on a global scale. Methods: Our survey was conducted in 75 countries through the Mission Thrombectomy 2020+ global network between November 22, 2020, and February 28, 2021. The primary end points were the current annual MTA, MT operator availability, and MT center availability. MTA was defined as the estimated proportion of patients with LVO receiving MT in a given region annually. The availability metrics were defined as ([current MT operators×50/current annual number of estimated thrombectomy-eligible LVOs]×100 = MT operator availability) and ([current MT centers×150/current annual number of estimated thrombectomy-eligible LVOs]×100= MT center availability). The metrics used optimal MT volume per operator as 50 and an optimal MT volume per center as 150. Multivariable-adjusted generalized linear models were used to evaluate factors associated with MTA. Results: We received 887 responses from 67 countries. The median global MTA was 2.79% (interquartile range, 0.70–11.74). MTA was <1.0% for 18 (27%) countries and 0 for 7 (10%) countries. There was a 460-fold disparity between the highest and lowest nonzero MTA regions and low-income countries had 88% lower MTA compared with high-income countries. The global MT operator availability was 16.5% of optimal and the MT center availability was 20.8% of optimal. On multivariable regression, country income level (low or lower–middle versus high: odds ratio, 0.08 [95% CI, 0.04–0.12]), MT operator availability (odds ratio, 3.35 [95% CI, 2.07–5.42]), MT center availability (odds ratio, 2.86 [95% CI, 1.84–4.48]), and presence of prehospital acute stroke bypass protocol (odds ratio, 4.00 [95% CI, 1.70–9.42]) were significantly associated with increased odds of MTA. Conclusions: Access to MT on a global level is extremely low, with enormous disparities between countries by income level. The significant determinants of MT access are the country’s per capita gross national income, prehospital LVO triage policy, and MT operator and center availability.

Introduction: Intravenous alteplase (tissue plasminogen activator) has been shown to be cost-effective due to savings in long-term disability. In October of 2005, an increased DRG payment to hospitals for alteplase-treated stroke patients was introduced. We sought to describe the trends in the cost of alteplase over time, in comparison to trends in hospital reimbursement in the United States. Methods: Utilizing publicly available information on the Centers for Medicare and Medicaid Services (CMS) website (www.cms.gov), we obtained CMS quarterly payment amounts between 1/1/2005-10/1/2014 for alteplase, listed as “alteplase recombinant, per mg.” CMS payment amounts are the manufacturer’s average sales price (ASP) + 6% until 4/2014, when it was lowered to + 4.3%. Estimates for DRG base payments were calculated within MEDPAR for FY 2006 (DRG 559) and 2013 (MS DRGs 61,62, and 63) as: (DRG relative weights) x (standardized operating and capital amount). The Consumer Price Index (CPI) was also queried for all prescription drugs, urban areas, during the same study period as reference. Results: The CMS payment amount for alteplase/mg was $30.50 in 1/2005, and $64.30 in 10/2014. Trends in the CMS payment amounts for alteplase increased by 111% between 2005-2014, shown in the Figure. The CPI for all prescription drugs increased by 30.2% in the same time frame. The base payment for alteplase-treated stroke admissions was $11,173 in 2006, and $12,064 in 2013, an 8% increase. Discussion: We found a striking increase in the cost of alteplase over the last decade, with a 100mg vial now with a CMS payment of ∼$6400, a more than 100% increase over ten years. During the same timeframe, the DRG base payment to hospitals increased by only 8%, and alteplase cost increased from 27% of the payment in 2006 to 53% in 2013. Researchers and stroke physicians should be aware of these changes in drug costs and their impact on cost-effectiveness analyses.

Introduction: Long-term cardiac monitoring studies have unveiled low-burden, occult atrial fibrillation (AF) in some patients with otherwise cryptogenic stroke (CS). But occult AF is also found in some normal individuals and patients with stroke of known cause (KS). Clinical management would be aided by estimates of how often occult AF in a patient with CS is causal versus incidental. Methods: Through systematic search, we identified all case-control and cohort studies applying identical long-term monitoring techniques to both CS and KS patients. We performed a random-effects meta-analyses across these studies to determine the best estimate of the differential frequency of occult AF in CS and KS among all patients, and across age subgroups. We then applied Bayes’ theorem (method of Alsheikh-Ali et al, Stroke 2009) to determine the probability that occult AF is causal or incidental. Results: The systematic search identified 3 case-control and cohort studies enrolling 575 patients (337 CS, 238 KS). Methods of long-term monitoring were implantable loop recorder in 191 (33.2%), extended mobile external cardiac monitor in 277 (48.2%), and patch/event/Holter monitoring in 107 (18.6%). In formal meta-analysis, the summary odds ratio for occult AF in CS vs KS in all patients was 1.72 (95%CI 0.91-3.25) (Figure). With application of Bayes theorem, the corresponding probabilities indicated that, when present, occult AF in CS patients is causal in 44.4% and incidental in 55.6%. Only one study reported age-specific subgroup data: these suggested occult AF in CS patients was causal in 93% of patients <65y vs 5.6% of patients ≥65y, but estimates had limited precision. Conclusions: In patients with cryptogenic stroke, when occult AF is found, it is likely causal in about 44% of patients, who may benefit from anticoagulation, and likely incidental in about 56% of patients, who may not benefit from anticoagulation. Figure

Introduction: In order to increase the efficiency and effectiveness of neurovascular clinical research studies, increase data quality, facilitate data sharing, help educate new clinical investigators and reduce study start-up time, the National Institute of Neurological Disorders and Stroke (NINDS) convened a Working Group (WG) that developed Version 1.0 (published 2010) Stroke-specific Common Data Elements (CDEs). Since their initial publication, intervening advances in science and initial experience with the CDEs identified a need to update them and refine guidance on their deployment. Hypothesis/Objective: The NINDS has updated guidance on uniform data structures for use in cerebrovascular research in epidemiology, clinical trials and imaging studies in order to advance the prevention, acute treatment and recovery from cerebrovascular disease. Methods: The NINDS convened experts in research and data element design drawing strongly from investigators in the NIH StrokeNet and other NINDS clinical research projects. Results: Stroke CDE leadership developed a revised process for classifying Stroke CDEs among the four hierarchical categories of Core, Supplemental - Highly Recommended, Supplemental and Exploratory. Due to the heterogeneity of stroke conditions and study types, the classification of Supplemental - Highly Recommended was used for study type (clinical trial or observational), disease type (e.g., ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage) and disease phase (primary prevention, acute, recovery and secondary prevention). Conclusion: The second iteration of NINDS CDE recommendations for neurovascular disease is an important step towards more efficient study start-up time and improved data sharing. The updated CDEs were released on the NINDS CDE website in May 2015. The information at this meeting will include examples of how the Stroke CDEs may be used by a research study, an explanation of the new CDE classifications, and examples of navigating and selecting CDEs from the NINDS CDE website. Support: This project was funded by HHSN271201200034C.

Introduction: Low rates of enrollment into stroke clinical trials are an ongoing challenge for the stroke research community. We sought to retrospectively describe the association between medical eligibility and recruitment rates for two acute clinical trials. Methods: Within a population of 1.3 million, we screened local hospital admissions in 2010 using ICD-9 discharge codes 430-436, and performed chart review. Within the region are 15 adult acute care hospitals, all of which are covered by the same stroke team for clinical care and trial enrollment. Medical eligibility, the number of eligible patients/total number of patients, was calculated for the IMS-III trial and the CLEAR-ER trials using their inclusion/exclusion criteria. The number of patients enrolled in the trial per month of open enrollment was determined for each hospital. Statistical analysis included paired signed rank test and regression. Results: In 2010, 2035 ischemic strokes (IS) were hospitalized in the region. Regional medical eligibility was 1.7% for IMS III and 4.5% for CLEARER (p=0.001), overall regional hospital enrollment/month was 0.81 for IMS III and 1.84 for CLEAR-ER (p=0.001). Eligibility rates per hospital ranged from 0-9.5%, and recruitment rates per hospital/mo ranged from 0-0.38. Hospital-level eligibility and recruitment rates were significantly correlated (see figure for both trials combined, adjusted r2 = 0.57, p<0.001.) Discussion: Within our population, medical eligibility explained 57% of the variability in hospital-level enrollment rates for two acute IS trials. The use of population-based epidemiology in trial planning may identify optimal trial enrollment criteria, which must be weighed against proper patient selection. Many other factors impact enrollment rates, such as competing trials, which were not considered here. Further evaluation of our population-based eligibility rates in sites outside our region and with additional clinical trials is needed.

Background and Purpose— Mechanical thrombectomy has been shown to improve clinical outcomes in patients with acute ischemic stroke. However, the impact of balloon guide catheter (BGC) use is not well established. Methods— STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter study of patients with large vessel occlusion treated with the Solitaire stent retriever as first-line therapy. In this study, an independent core laboratory, blinded to the clinical outcomes, reviewed all procedures and angiographic data to classify procedural technique, target clot location, recanalization after each pass, and determine the number of stent retriever passes. The primary clinical end point was functional independence (modified Rankin Scale, 0–2) at 3 months as determined on-site, and the angiographic end point was first-pass effect (FPE) success rate from a single device attempt (modified Thrombolysis in Cerebral Infarction, ≥2c) as determined by a core laboratory. Achieving modified FPE (modified Thrombolysis in Cerebral Infarction, ≥2b) was also assessed. Comparisons of clinical outcomes were made between groups and adjusted for baseline and procedural characteristics. All participating centers received institutional review board approval from their respective institutions. Results— Adjunctive technique groups included BGC (n=445), distal access catheter (n=238), and conventional guide catheter (n=62). The BGC group had a higher rate of FPE following first pass (212/443 [48%]) versus conventional guide catheter (16/62 [26%]; P =0.001) and distal access catheter (83/235 [35%]; P =0.002). Similarly, the BGC group had a higher rate of modified FPE (294/443 [66%]) versus conventional guide catheter (26/62 [42%]; P <0.001) and distal access catheter (129/234 [55%]; P =0.003). The BGC group achieved the highest rate of functional independence (253/415 [61%]) versus conventional guide catheter (23/55 [42%]; P =0.007) and distal access catheter (113/218 [52%]; P =0.027). Final revascularization and mortality rates did not differ across the groups. Conclusions— BGC use was an independent predictor of FPE, modified FPE, and functional independence, suggesting that its routine use may improve the rates of early revascularization success and good clinical outcomes. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT02239640.

Background: Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation. Methods: STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0–2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass. Results: A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients ( P <0.001). Clinical outcomes were better in the direct group, with 60.0% (299/498) achieving functional independence compared with 52.2% (213/408) in the transfer group (odds ratio, 1.38; 95% confidence interval, 1.06–1.79; P =0.02). Likewise, excellent outcome (modified Rankin Score 0–1) was achieved in 47.4% (236/498) of direct patients versus 38.0% (155/408) of transfer patients (odds ratio, 1.47; 95% confidence interval, 1.13–1.92; P =0.005). Mortality did not differ between the 2 groups (15.1% for direct, 13.7% for transfer; P =0.55). Intravenous tissue plasminogen activator did not impact outcomes. Hypothetical bypass modeling for all transferred patients suggested that intravenous tissue plasminogen activator would be delayed by 12 minutes, but MT would be performed 91 minutes sooner if patients were routed directly to endovascular-capable centers. If bypass is limited to a 20-mile radius from onset, then intravenous tissue plasminogen activator would be delayed by 7 minutes and MT performed 94 minutes earlier. Conclusions: In this large, real-world study, interhospital transfer was associated with significant treatment delays and lower chance of good outcome. Strategies to facilitate more rapid identification of large-vessel occlusion and direct routing to endovascular-capable centers for patients with severe stroke may improve outcomes. Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT02239640.

Background and Purpose— Intravenous alteplase (tissue-type plasminogen activator) has been shown to be cost-effective because of savings in long-term disability. In October of 2005, an increased DRG payment to hospitals for alteplase-treated stroke patients was introduced. We sought to describe the trends in the cost of alteplase over time, in comparison to trends in hospital reimbursement in the United States. Methods— Using publicly available information on the Centers for Medicare and Medicaid Services (CMS) website ( www.cms.gov ), we obtained CMS quarterly payment amounts between January 1, 2005, and October 1, 2014, for alteplase, listed as alteplase recombinant, per mg. CMS payment amounts are the manufacturer’s average sales price+6% until April 2014, when it was lowered to +4.3%. Estimates for DRG base payments were calculated within the Medicare Provider and Analysis Review (MEDPAR) for fiscal years 2006 (DRG 559) and 2013 (MS DRGs 61, 62, and 63) as (DRG relative weights)×(standardized operating and capital amount). The consumer price index was also queried for all prescription drugs, urban areas, during the same study period as reference. Results— The CMS payment amount for alteplase per milligram was $30.50 in January 2005 and $64.30 in October 2014. Trends in the CMS payment amounts for alteplase increased by 111% between 2005 and 2014. The consumer price index for all prescription drugs increased by 30.2% in the same time frame. The base payment for alteplase-treated stroke admissions was $11 173 in 2006 and $12 064 in 2013, an 8% increase. Conclusions— We found a striking increase in the cost of alteplase over the last decade, with a 100 mg vial now with a CMS payment of ≈$6400, a >100% increase over 10 years. During the same time frame, the DRG base payment to hospitals increased by only 8%, and alteplase cost increased from 27% of the payment in 2006 to 53% in 2013. Researchers and stroke physicians should be aware of these changes in drug costs and their impact on cost-effectiveness analyses.