Mechanical thrombectomy is cost-effective versus medical management alone around Europe in patients with low ASPECTS

Success with incrementally faster times to endovascular therapy (SWIFT-EVT): A systematic review and meta-analysis

BACKGROUND

A major systematic review and meta-analysis assessing trial data through 2014 (the Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials, HERMES) demonstrated that particularly over the initial six hours of acute ischemic stroke (AIS), rapid performance of endovascular therapy (EVT) markedly improves outcomes. The current analysis, Success with Incrementally Faster Times to EVT (SWIFT-EVT), aimed to provide an updated metric summarizing latest estimates for modified Rankin Scale (mRS) improvements accrued by streamlining time to EVT.

METHODS

A systematic review and meta-analysis was conducted using electronic databases. Eligible studies reported a time-benefit slope with times from AIS onset (or time last known normal) to EVT commencement; the predictor was onset-to-groin (OTG) time. Primary and secondary outcomes were 90-day functional independence (mRS 0-2) and 90-day excellent function (mRS 0-1), respectively.

RESULTS

Five studies were included. Results showed increased change of good outcome with each hour of pre-EVT time savings for mRS 0-2 for 0-270' (OR 1.25, 95 % CI 1.16-1.35, I2 40 %) and 271-360' time frame (1.22, 95 % CI 1.12-1.33, I2 58 %). For the studies assessing mRS 0-1, estimates were found appropriate for both the 0-270' time frame (OR 1.34, 95 % CI 1.19-1.51, I2 27 %) and the 271-360' time frame (OR 1.20, 95 % CI 1.03-1.38, I2 60 %).

CONCLUSIONS

Each hour saved from AIS onset to EVT start is associated with a 22-25 % increased odds of achieving functional independence, a useful metric to inform patient-specific and systems planning decisions.

New Perspectives in Neuroprotection for Ischemic Stroke

The constant failure of new neuroprotective therapies for ischemic stroke has partially halted the search for new therapies in recent years, mainly because of the high investment risk required to develop a new treatment for a complex pathology, such as stroke, with a narrow intervention window and associated comorbidities. However, owing to recent progress in understanding the stroke pathophysiology, improvement in patient care in stroke units, development of new imaging techniques, search for new biomarkers for early diagnosis, and increasingly widespread use of mechanical recanalization therapies, new opportunities have opened for the study of neuroprotection. This review summarizes the main protective agents currently in use, some of which are already in the clinical evaluation phase. It also includes an analysis of how recanalization therapies, new imaging techniques, and biomarkers have improved their efficacy.

Cost-effectiveness of endovascular thrombectomy for acute ischemic stroke with established large infarct in Germany: a decision tree and Markov model

BACKGROUND

Recent studies, including the TENSION trial, support the use of endovascular thrombectomy (EVT) in acute ischemic stroke with large infarct (Alberta Stroke Program Early Computed Tomography Score (ASPECTS) 3-5).

OBJECTIVE

To evaluate the cost-effectiveness of EVT compared with best medical care (BMC) alone in this population from a German healthcare payer perspective.

METHODS

A short-term decision tree and a long-term Markov model (lifetime horizon) were used to compare healthcare costs and quality-adjusted life years (QALYs) between EVT and BMC. The effectiveness of EVT was reflected by the 90-day modified Rankin Scale (mRS) outcome from the TENSION trial. QALYs were based on published mRS-specific health utilities (EQ-5D-3L indices). Long-term healthcare costs were calculated based on insurance data. Costs (reported in 2022 euros) and QALYs were discounted by 3% annually. Cost-effectiveness was assessed using incremental cost-effectiveness ratios (ICERs). Deterministic and probabilistic sensitivity analyses were performed to account for parameter uncertainties.

RESULTS

Compared with BMC, EVT yielded higher lifetime incremental costs (€24 257) and effects (1.41 QALYs), resulting in an ICER of €17 158/QALY. The results were robust to parameter variation in sensitivity analyses (eg, 95% probability of cost-effectiveness was achieved at a willingness to pay of >€22 000/QALY). Subgroup analyses indicated that EVT was cost-effective for all ASPECTS subgroups.

CONCLUSIONS

EVT for acute ischemic stroke with established large infarct is likely to be cost-effective compared with BMC, assuming that an additional investment of €17 158/QALY is deemed acceptable by the healthcare payer.

Outcomes of mechanical thrombectomy in stroke patients with extreme large infarction core

BACKGROUND

Recent clinical trials have demonstrated that patients with large vessel occlusion (LVO) and large infarction core may still benefit from mechanical thrombectomy (MT). In this study, we evaluate outcomes of MT in LVO patients presenting with extremely large infarction core Alberta Stroke Program Early CT Score (ASPECTS 0-2).

METHODS

Data from the Stroke Thrombectomy and Aneurysm Registry (STAR) was interrogated. We identified thrombectomy patients presenting with an occlusion in the intracranial internal carotid artery (ICA) or M1 segment of the middle cerebral artery and extremely large infarction core (ASPECTS 0-2). A favorable outcome was defined by achieving a modified Rankin scale of 0-3 at 90 days post-MT. Successful recanalization was defined by achieving a modified Thrombolysis In Cerebral Ischemia (mTICI) score ≥2B.

RESULTS

We identified 58 patients who presented with ASPECTS 0-2 and underwent MT. Median age was 74.0 (66.3-80.0) years, 30 (51.7%) were females, and 16 (27.6%) patients received intravenous tissue plasminogen activator. There was no difference regarding the location of the occlusion (p=0.57). Aspiration thrombectomy was performed in 34 (64.2%) patients and stent retriever was used in 8 (15.1%) patients. In patients presenting with ASPECTS 0-2 the mortality rate was 41.4%, 31% had mRS 0-3 at day 90, 66.67% ≥70 years of age had mRS of 5-6 at day 90. On multivariable analysis, age, National Institutes of Health Stroke Scale on admission, and successful recanalization (mTICI ≥2B) were independently associated with favorable outcomes.

CONCLUSIONS

This multicentered, retrospective cohort study suggests that MT may be beneficial in a select group of patients with ASPECTS 0-2.

Safety and clinical outcomes of endovascular therapy versus medical management in late presentation of large ischemic stroke

INTRODUCTION

The benefit of endovascular therapy (EVT) among stroke patients with large ischemic core (ASPECTS 0-5) in the extended time window outside of trial settings remains unclear. We analyzed the effect of EVT among these stroke patients in real-world settings.

PATIENTS AND METHODS

The CT for Late Endovascular Reperfusion (CLEAR) study recruited patients from 66 centers in 10 countries between 01/2014 and 05/2022. The extended time-window was defined as 6-24 h from last-seen-well to treatment. The primary outcome was shift of the 3-month modified Rankin scale (mRS) score. Safety outcomes included symptomatic intracranial hemorrhage (sICH) and mortality. Outcomes were analyzed with ordinal and logistic regressions.

RESULTS

Among 5098 screened patients, 2451 were included in the analysis (median age 73, 55% women). Of patients with ASPECTS 0-5 (n = 310), receiving EVT (n = 209/310) was associated with lower 3-month mRS when compared to medical management (median 4 IQR 3-6 vs 6 IQR 4-6; aOR 0.4, 95% CI 0.2-0.7). Patients undergoing EVT had higher sICH (11.2% vs 4.0%; aOR 4.1, 95% CI 1.2-18.8) and lower mortality (31.6% vs 58.4%, aOR 0.4; 95% CI 0.2-0.9) compared to medically managed patients. The relative benefit of EVT was comparable between patients with ASPECTS 0 and 5 and 6-10 in the extended time window (interaction aOR 0.9; 95% CI 0.5-1.7).

CONCLUSION

In the extended time window, patients with ASPECTS 0-5 may have preserved relative treatment benefit of EVT compared to patients with ASPECTS 6-10. These findings are in line with recent trials showing benefit of EVT among real-world patients with large ischemic core in the extended time window.

TRIAL REGISTRATION NUMBER

clinicaltrials.gov; Unique identifier: NCT04096248.

Health budget implications of mechanical thrombectomy for acute ischaemic stroke in Australia

INTRODUCTION

This research evaluates the budget impact of treating acute ischaemic stroke (AIS) using a combination of mechanical thrombectomy (MT) with stent retrievers (SR) and intravenous tissue-plasminogen activator (IV-tPA) in Australia.

METHODS

This study examined the economic impact over five years for a patient cohort based on the number of patients treated with MT+ IV-tPA in Australia 2021, versus treatment with IV-tPA alone. A budget impact (BI) model was developed to project direct medical costs (economic impact) of IV-tPA+ MT with SR vs. Intravenous tissue-plasminogen activator alone over a five-year period (2021-2025 inclusive) from a healthcare perspective. The model is composed of a short-run decision tree model based on a 3-month post-treatment modified Rankin Scale (mRS) from the EXTEND-IA study and a published long-run Markov state transition model. Acute, mid-term and long-term care costs were projected based on anticipated mRS scores from the EXTEND-IA trial. Estimated yearly and cumulative budget impact were reported to indicate the economic impact of the two treatment strategies for AIS in the Australian healthcare system.

RESULTS

MT+IV-tPA had a greater budgetary impact than IV-tPA alone, with annual savings starting at Year 1 and continuing through to Year 5. Cost savings of 21% or approximately $36 million can be achieved over five years for the patient cohort treated in Australia in 2021. Each MT procedure performed delivers approximately $3280 in annual health system savings per patient.

CONCLUSION

Treatment of AIS with a combination of MT+IV-tPA generates significant savings in the Australian healthcare system compared with IV-tPA alone.

Cost-effectiveness of endovascular therapy for acute ischemic stroke with large infarct in China

BACKGROUND

Endovascular therapy administered within 24 hours has been shown to improve outcomes for patients with acute ischemic stroke with large infarction, but the data on its cost-effectiveness are limited.

OBJECTIVE

To evaluate the cost-effectiveness of endovascular therapy for acute ischemic stroke with large infarction in China, the largest low- and middle-income country.

METHODS

A short-term decision tree model and a long-term Markov model were used to analyze the cost-effectiveness of endovascular therapy for patients with acute ischemic stroke with large infarction. Outcomes, transition probability, and cost data were obtained from a recent clinical trial and published literature. The benefit of endovascular therapy was assessed by the cost per quality-adjusted life-years (QALYs) gained in the short and long term. Deterministic one-way and probabilistic sensitivity analyses were performed to assess the robustness of the results.

RESULTS

Compared with medical management alone, endovascular therapy for acute ischemic stroke with large infarction was found to be cost-effective from the fourth year onward and during a lifetime. In the long term, endovascular therapy yielded a lifetime gain of 1.33 QALYs at an additional cost of ¥73 900 (US$ 11 400), resulting in an incremental cost of ¥55 500 (US$ 8530) per QALY gained. Probabilistic sensitivity analysis showed that endovascular therapy was cost-effective in 99.5% of the simulation runs at a willingness-to-pay threshold of ¥243 000 (3 × gross domestic product per capita of China in 2021) per QALY gained.

CONCLUSIONS

Endovascular therapy for acute ischemic stroke with large infarction could be cost-effective in China.

Endovascular thrombectomy is cost-saving in patients with acute ischemic stroke with large infarct

Objective

Endovascular thrombectomy (EVT) is the standard of care for acute large vessel occlusion stroke. Recently, the ANGEL-ASPECT and SELECT 2 trials showed improved outcomes in patients with acute ischemic Stroke presenting with large infarcts. The cost-effectiveness of EVT for this subpopulation of stroke patients has only been calculated using data from the previously published RESCUE-Japan LIMIT trial. It is, therefore, limited in its generalizability to an international population. With this study we primarily simulated patient-level costs to analyze the economic potential of EVT for patients with large ischemic stroke from a public health payer perspective based on the recently published data and secondarily identified determinants of cost-effectiveness.

Methods

Costs and outcome of patients treated with EVT or only with the best medical care based on the recent prospective clinical trials ANGEL-ASPECT, SELECT2 and RESCUE-Japan LIMIT. A A Markov model was developed using treamtment outcomes derived from the most recent available literature. Deterministic and probabilistic sensitivity analyses addressed uncertainty.

Results

Endovascular treatment resulted in an incremental gain of 1.32 QALYs per procedure with cost savings of $17,318 per patient. Lifetime costs resulted to be most sensitive to the costs of the endovascular procedure.

Conclusion

EVT is a cost-saving (i.e., dominant) strategy for patients presenting with large ischemic cores defined by inclusion criteria of the recently published ANGEL-ASPECT, SELECT2, and RESCUE-Japan LIMIT trials in comparison to best medical care in our simulation. Prospective data of individual patients need to be collected to validate these results.

Factors associated with decreasing diffusion-weighted imaging-positive area volume after mechanical thrombectomy in patients with large early ischemic changes

OBJECTIVES

This study aimed to evaluate the factors associated with decreasing diffusion-weighted imaging (DWI) positive areas in patients with large early ischemic changes after mechanical thrombectomy (MT).

MATERIALS AND METHODS

This retrospective single-center clinical study was conducted between January 2013 and December 2022. We included consecutive patients who underwent MT for acute large-vessel occlusion of the anterior circulation with low pretreatment DWI-Alberta Stroke Program Early Computed Tomography Scores (ASPECTS) (0-5), effective recanalization [thrombolysis in cerebral infarction (TICI) 2b or TICI3], and magnetic resonance imaging (MRI) acquired before and after MT. We measured the DWI-positive area volume before and after MT. The primary endpoint was the after/before-MT DWI-positive area-volume ratio.

RESULTS

In total, 28 patients were included in this study. Eight patients (29%) had an after/before-MT DWI-positive area-volume ratio of <1. The median mean apparent diffusion coefficient (ADC) levels of the DWI-positive areas in the groups with a ratio of <1 or >1 were 717 × 10⁶ mm2/s and 637 × 106 mm2/s, respectively (p = 0.011). Multivariate logistic regression analysis showed that ADC level (OR, 1.020 [95% confidence intervals (CIs), 1.001-1.040]; p = 0.040) was an independent predictor of a decreased DWI-positive area after MT. There was a negative correlation between the mean ADC level and the after/before-MT DWI-positive area-volume ratio (p < 0.001, |ρ| = 0.650), and the mean pretreatment ADC cutoff level was 649 × 106 mm2/s (area under the curve (AUC) = 0.806) for predicting a volume ratio of <1.

CONCLUSIONS

The mean ADC level before-MT correlated with the after/before-MT DWI-positive area-volume ratio. A mean pretreatment ADC cutoff level of 649 × 106 mm2/s predicted a decreased DWI-positive area after MT.

Region-specific interobserver agreement of the Alberta Stroke Program Early Computed Tomography Score: A meta-analysis

BACKGROUND AND PURPOSE

The Alberta Stroke Program Early CT Score (ASPECTS) is a widely used scoring system for evaluating ischemic stroke to determine therapeutic strategy. However, there is variation in the interobserver agreement of ASPECTS. This systematic review and meta-analysis aimed to investigate the interobserver agreement of total and regional ASPECTS.

METHODS

A comprehensive search was conducted in the Web of Sciences, PubMed, and Scopus databases to identify relevant studies. Inclusion criteria were studies of noncontrast CT performed within 24 hours of ischemic stroke in the middle cerebral artery territory.

RESULTS

A total of 20 studies, with 3482 patients, reporting interobserver agreement of total and regional ASPECTS were included in the meta-analysis. The interobserver agreement for total ASPECTS in studies using Kappa coefficient (κ) analysis was substantial (κ = .67, 95% confidence interval [CI]: .57-.78). In studies using intraclass correlation coefficient (ICC) analysis, agreement was excellent (ICC = .84, 95% CI: .77-.90). Interobserver agreement was higher in studies in which the observer was unblinded to clinical scenario in both groups (κ = .74, 95% CI: .59-.89, and ICC = .82, 95% CI: .79-.85). Per-region analysis showed that the caudate nucleus had the highest agreement (κ = .68, 95% CI: .60-.76, and ICC = .84, 95% CI: .74-.93), while M2 and internal capsule in Kappa studies (κ = .45, 95% CI: .34-.55 and κ = .47, 95% CI: .28-.66), and M4 and internal capsule in ICC studies (ICC = .54, 95% CI: .43-.64 and ICC = .55, 95% CI: .18-.91) had the lowest agreement.

CONCLUSION

This meta-analysis demonstrates substantial to excellent interobserver agreement for total ASPECTS, which supports using this method for stroke treatment. However, findings emphasize the need to consider interobserver agreement in specific regions of ASPECTS for treatment decisions.

Cost-effectiveness of endovascular therapy for acute stroke with a large ischemic region in Japan: impact of the Alberta Stroke Program Early CT Score on cost-effectiveness

BACKGROUND

Although randomized clinical trials (RCTs) demonstrated short-term benefits of endovascular therapy (EVT) for acute ischemic stroke (AIS) with a large ischemic region, little is known about the long-term cost-effectiveness or its difference by the extent of the ischemic areas. We aimed to assess the cost-effectiveness of EVT for AIS involving a large ischemic region from the perspective of Japanese health insurance payers, and analyze it using the Alberta Stroke Program Early CT Score (ASPECTS).

METHODS

The Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism-Japan Large Ischemic Core Trial (RESCUE-Japan LIMIT) was a RCT enrolling AIS patients with ASPECTS of 3-5 initially determined by the treating neurologist primarily using MRI. The hypothetical cohort and treatment efficacy were derived from the RESCUE-Japan LIMIT. Costs were calculated using the national health insurance tariff. We stratified the cohort into two subgroups based on ASPECTS of ≤3 and 4-5 as determined by the imaging committee, because heterogeneity was observed in treatment efficacy. EVT was considered cost-effective if the incremental cost-effectiveness ratio (ICER) was below the willingness-to-pay of 5 000 000 Japanese yen (JPY)/quality-adjusted life year (QALY).

RESULTS

EVT was cost-effective among the RESCUE-Japan LIMIT population (ICER 4 826 911 JPY/QALY). The ICER among those with ASPECTS of ≤3 and 4-5 was 19 396 253 and 561 582 JPY/QALY, respectively.

CONCLUSION

EVT was cost-effective for patients with AIS involving a large ischemic region with ASPECTS of 3-5 initially determined by the treating neurologist in Japan. However, the ICER was over 5 000 000 JPY/QALY among those with an ASPECTS of ≤3 as determined by the imaging committee.

Cost-effectiveness of Endovascular Treatment for Acute Stroke with Large Infarct: A United States Perspective

Background The health economic benefit of endovascular treatment (EVT) in addition to best medical management for acute ischemic stroke with large ischemic core is uncertain. Purpose To assess the cost-effectiveness of EVT plus best medical management versus best medical management alone in treating acute ischemic stroke with large vessel occlusion and a baseline Alberta Stroke Program Early CT Score (ASPECTS) 3-5. Materials and Methods This is a secondary analysis of the randomized RESCUE-Japan LIMIT (Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism-Japan Large Ischemic Core Trial), with enrollment November 2018 to September 2021, in which the primary outcome was the modified Rankin Scale (mRS) score at 90 days. Participants with a baseline ASPECTS 3-5 (on the basis of noncontrast CT and diffusion-weighted imaging) were randomized 1:1 to receive EVT plus best medical management (n = 100) or best medical management alone (n = 102). The primary outcome of the current study was cost-effectiveness, determined according to the incremental cost-effectiveness ratio (ICER). A decision model consisting of a short-term component (cycle length of 3 months) and a long-term Markov state transition component (cycle length of 1 year) was used to estimate expected lifetime costs and quality-adjusted life-years (QALYs) from health care and societal perspectives in the United States. Upper and lower willingness-to-pay (WTP) thresholds were set at $100 000 and $50 000 per QALY, respectively. A deterministic one-way sensitivity analysis to determine the impact of participant age and a probabilistic sensitivity analysis to assess the impact of parameter uncertainty were conducted. Results A total of 202 participants were included in the study (mean age, 76 years ± 10 [SD]; 112 male). EVT plus best medical management resulted in ICERs of $15 743 (health care perspective) and $19 492 (societal perspective). At the lower and upper WTP thresholds, EVT was cost-effective up to 85 and 90 years (health care perspective) and 84 and 89 years (societal perspective) of age, respectively. When analyzing participants with the largest infarcts (ASPECTS 3) separately, EVT was not cost-effective (ICER, $337 072 [health care perspective] and $383 628 [societal perspective]). Conclusion EVT was cost-effective for participants with an ASPECTS 4-5, but not for those with an ASPECTS 3. ClinicalTrials.gov registration no. NCT03702413 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Widjaja in this issue.