Highlight
– Quantitative volumetry outperforms the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) in prognosticating outcomes after thrombectomy in large-core ischemic stroke.
– A volumetric infarct size threshold of 110 mL demarcates the therapeutic ceiling beyond which thrombectomy’s efficacy is negligible.
– Patients classified as large-core by ASPECTS but without volumetric confirmation do not demonstrate the poor outcomes associated with true large infarct volumes.
– Integration of volumetry into clinical decision-making could minimize futile reperfusion and enhance patient safety.
Study Background
Acute ischemic stroke caused by large vessel occlusion is a major cause of death and long-term disability worldwide. Endovascular thrombectomy has revolutionized treatment, especially in patients with favorable baseline imaging. For patient selection, the ASPECTS—a topographical CT scoring system—has been widely adopted to estimate ischemic core size. Yet, ASPECTS may inadequately capture the actual infarct volume, potentially overestimating or underestimating brain tissue damage, limiting its capacity to define the upper boundary—the therapeutic ceiling—beyond which mechanical thrombectomy offers diminishing returns or even harm. Defining this ceiling is critical to prevent futile reperfusion attempts and associated complications, optimizing resource allocation, and protecting patient safety.
Study Design
This investigation used data from a nationwide multicenter registry in Korea, enrolling 552 patients treated with endovascular thrombectomy between 2022 and 2024 for large vessel occlusion strokes. The study population included patients classified as having large core infarcts by ASPECTS and/or volumetric infarct measurement derived from diffusion-weighted imaging (DWI), computed tomography perfusion (CTP), and noncontrast computed tomography (NCCT). The primary endpoint was poor functional outcome, defined as a modified Rankin Scale (mRS) score of 5-6 at 90 days post-stroke. The researchers compared the prognostic discrimination between ASPECTS and quantitative volumetry. To estimate treatment effects according to infarct volume, they conducted target trial emulations stratifying causal estimates across various volumetric thresholds, focusing on ordinal mRS shift as the outcome measure.
Key Findings
The cohort had a mean age of 70.4 years, with 57.8% male patients. Notably, patients labeled large-core by ASPECTS but without volumetric confirmation via DWI (“ASPECTS-only large core”) had a poor outcome rate similar to patients with small infarcts confirmed volumetrically (11.8% vs. 11.7%). This subgroup showed no excess adjusted risk for poor functional outcome. Conversely, patients with large core infarcts confirmed across modalities — DWI, CTP, and NCCT — exhibited significantly worse prognosis regardless of ASPECTS status, with an adjusted odds ratio (OR) of 6.92 (95% CI, 2.58-19.34) for the DWI-confirmed large core group compared to patients with small cores.
The target trial emulation demonstrated an overall attenuated benefit of thrombectomy in large-core patients (common OR 0.56, 95% CI 0.31-1.03). Stratified by infarct volume, thrombectomy showed significant benefit within the 50 to 110 mL range (common OR 0.38, 95% CI 0.15-0.97), but this benefit disappeared in patients with infarcts larger than 110 mL. The authors thereby identified 110 mL as a data-driven therapeutic ceiling for thrombectomy efficacy in large-core strokes.
Expert Commentary
The findings challenge the sole reliance on ASPECTS for large-core stroke patient triage. ASPECTS, while practical and rapid, is a semi-quantitative score limited by its anatomical topography-based methodology, which does not always correspond precisely with actual infarct volume, especially in subcortical or deep structures. Quantitative volumetry, derived from advanced imaging modalities, offers a more objective and accurate estimation of ischemic damage extent. Establishing a volume cutoff at 110 mL provides a tangible metric for clinicians to identify patients unlikely to benefit from thrombectomy, thereby avoiding unnecessary procedural risks and healthcare expenditures.
Nevertheless, the study’s limitations should be considered, including its observational design and potential residual confounding, despite causal inference methods. Additionally, exact volumetric thresholds may differ based on imaging protocols and thrombectomy techniques across centers. Replication in diverse populations and incorporation into randomized trials will be essential to validate these findings.
Conclusion
This large multicenter study underscores that quantitative volumetry surpasses ASPECTS in predicting functional outcomes and defining the therapeutic limits of thrombectomy in large-core ischemic stroke. The identification of 110 mL infarct volume as a clinical cutoff delineates a therapeutic ceiling beyond which thrombectomy is unlikely to yield substantial benefits. Integrating volumetric assessments into routine stroke workflows could enhance patient selection, minimize futile reperfusion, and promote safer, evidence-based care. Future guidelines may incorporate volumetric metrics to refine acute stroke management strategies further.
Funding and ClinicalTrials.gov
The study was supported by institutional and governmental research grants as detailed in the primary publication. NS not specified here. Clinical trial registration was not indicated explicitly in the abstract or citation.
References
- Kim H, Ryu WS, Inoue M, et al. Defining the Therapeutic Ceiling of Endovascular Thrombectomy in Large-Core Stroke: Beyond the Limits of ASPECTS. Stroke. 2026 Jul 6. PMID: 42403349. PubMed.
- Albers GW, Marks MP, Kemp S, et al. Thrombectomy for Stroke at 6 to 16 Hours with Selection by Perfusion Imaging. N Engl J Med. 2018;378(8):708-718.
- Jovin TG, Chamorro A, Cobo E, et al. Thrombectomy within 8 Hours after Symptom Onset in Ischemic Stroke. N Engl J Med. 2015;372(24):2296-2306.
- Demchuk AM, Goyal M, Yeatts SD, et al. Reperfusion of Target Tissues with Endovascular Therapy for Stroke: Effect of Core Volume. Ann Neurol. 2021;89(3):699-707.
