Article Commentary: “CTP-Defined Large Core Is a Better Predictor of Poor Outcome for Endovascular Treatment Than ASPECTS-Defined Large Core”

Oh fuck, when will management stop with the research that predicts failure to recover and do useful research like maybe: GETTING SURVIVORS RECOVERED!

I'd have all of management here fired!

Article Commentary: “CTP-Defined Large Core Is a Better Predictor of Poor Outcome for Endovascular Treatment Than ASPECTS-Defined Large Core”

• Mitch Wilson, MD, MSc

Originally published April 26, 2024 10.1161/blog.20240426.448200

Sui Y, Chen W, Chen C, Chang Y, Bivard A, Wang P, Geng Y, Parsons M, Lin L, INSPIRE Investigators. CTP-Defined Large Core Is a Better Predictor of Poor Outcome for Endovascular Treatment Than ASPECTS-Defined Large Core. Stroke. 2024.

The authors of the present study address an important and topical question: What is the best imaging modality to define large core infarcts?

Over the last 2 years, multiple RCTs (RESCUE-Japan Limit, ANGEL-ASPECT, SELECT-2) have demonstrated the efficacy of endovascular thrombectomy (EVT) for large core infarcts. These studies used a combination of modalities to define large core, including non-contrast head CT (NCCT) using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS), as well as advanced imaging, such as CT perfusion (CTP) and MRI. More recently, in the TENSION trial, EVT improved outcomes when NCCT/ASPECTS was used as the sole imaging modality to measure core infarct size. 

Here, the authors performed a retrospective cohort study to determine whether functional outcomes differed when large core was defined by NCCT versus CTP. Patients were selected from the International Stroke Perfusion Imaging Registry (INSPIRE), a large cohort of patients with acute ischemic stroke, all of whom underwent NCCT and CTP. Patients included in this study represented a subset of the INSPIRE registry who had large vessel occlusion treated with EVT. Large core was defined as ASPECTS ≤5 by NCCT or core volume ≥70mL by CTP. The primary outcome was a poor functional outcome as determined by a modified Rankin Scale (mRS) score of 5-6 at 3 months. 

In total, there were 1115 patients with LVO who underwent EVT, of which 90 (8.1%) had ASPECTS ≤5 and 97 (8.7%) had CTP core ≥70 mL. Patients were categorized into 1 of 4 groups: 1) ASPECTS >5 and CTP<70mL (N=962); 2) ASPECTS ≤5 and CTP <70mL (N=56); 3) ASPECTS >5 and CTP ≥70mL (N=63); and 4) ASPECTS ≤5 and CTP ≥70mL (N=34). Compared to group 1 (no large core by NCCT or CTP), patients in group 2 (ASPECTS-defined large core) were equally likely to have a poor functional outcome at 3 months (29% vs 23%, adjusted OR 1.84 [0.91–3.73]; P=0.089). Conversely, compared to group 1, patients in group 3 (CTP-defined large core) were more likely to have a poor functional outcome (60% vs 23%, adjusted OR 3.91 [2.01–7.60]; P<0.001). In a subgroup analysis, it was demonstrated that when EVT was performed after 6 hours, patients with ASPECTS ≤5 were more likely to have a poor outcome than those with ASPECTS >5 (50% versus 27%, P=0.004), whereas when EVT was performed within 6 hours, there was no difference in the proportion with a poor outcome between ASPECTS ≤5 vs >5. CTP-defined large core showed increased likelihood of poor outcome in both time strata. 

The results of this study suggest that CTP-defined large core may provide better prognostic information than ASPECTS-defined large core, particularly during the early time window — when CTP is not recommended in the current American Heart Association guidelines. These findings provide some evidence that foregoing CTP for patients with large core infarcts may lead to more patients undergoing EVT that are unlikely to benefit.