Utility of Endovascular Thrombectomy in Patients With Large Infarct Cores

In late 2014, a significant breakthrough occurred in treating ischemic strokes. The MR CLEAN trial revealed that endovascular thrombectomy (EVT) led to improved functional independence in patients with anterior circulation large vessel occlusions if performed within six hours of symptom onset compared with standard medical management alone.¹ The inclusion criteria for EVT was later expanded in 2018, after the DAWN and DEFUSE 3 trials demonstrated that EVT resulted in improved outcomes in patients presenting within 24 hours of symptom onset, provided they completed a strategic imaging screening process to evaluate size of the core infarct compared to the size of ischemic injury.²
 
The screening process used CT perfusion to detect ischemic injury and core infarct sizes and Alberta Stroke Program Early CT Scores (ASPECTS) to evaluate large and small strokes with high ASPECTS of 8 to 10 (out of 10) indicating small or no evidence of early infarction. The ANGEL-ASPECT and SELECT 2 studies showed that patients with lower ASPECTS (5-6), indicating larger strokes, who underwent EVT had favorable outcomes compared to patients who received standard medical care.³
 
To examine the clinical outcomes of patients with large core infarcts and very low ASPECTS (< 3) who underwent EVT, Katsanos et al performed a systematic review and meta-analysis by performing a literature search on randomized controlled trials (RCTs) evaluating the utility of EVT in patients with large infarct cores.⁴ After excluding studies that did not provide adequate data for the subgroup of patients presenting with baseline ASPECTS between 0 and 2, the study was narrowed down to two relevant trials, ANGEL-ASPECT and SELECT 2.
 
In the SELECT 2 trial, 5.7% of patients had ASPECTS less than 3. In the ANGEL-ASPECT trial, 13.6% of patients had ASPECTS less than 3. Analysis pooled from this subgroup of patients showed a statistically significant shift in the distribution of modified Rankin Scale scores toward better outcomes in favor of EVT (generalized OR 1.46; 95% CI, 1.03-2.07). The authors concluded that the benefit of EVT persists in patients with even the lowest ASPECTS.
 
A separate systematic review and meta-analysis of randomized and observational studies had similar findings,⁵ whereas a post hoc analysis from the RESCUE-Japan LIMIT trial showed contradictory results.⁶
 
While further validation is needed, Katsanos et al suggests that the current use of clinical and imaging parameters to screen patients with large stroke prior to EVT could be excluding patients who could benefit from EVT.⁴ This study is limited by the sparse number of RCTs included for review. Additional trials are needed to weigh the benefits of EVT against the risks in patients with extremely large core infarcts.
 
 
References

1. Berkhemer OA, Fransen PS, Beumer D, et al; MR CLEAN Investigators. A randomized trial of intraarterial treatment for acute ischemic stroke. N Engl J Med. 2015 Jan 1;372(1):11-20.
2. Albers GW, Marks MP, Kemp S, et al; DEFUSE 3 Investigators. Thrombectomy for stroke at 6 to 16 hours with selection by perfusion imaging. N Engl J Med. 2018 Feb 22;378(8):708-718.
3. Huo X, Ma G, Tong X, et al; ANGEL-ASPECT Investigators. Trial of endovascular therapy for acute ischemic stroke with large infarct. N Engl J Med. 2023 Apr 6;388(14):1272-1283.
4. Katsanos AH, Catanese L, Shoamanesh A. Endovascular thrombectomy in patients with very low ASPECTS scores: a systematic review and meta-analysis. Neurology. 2023 Nov 14;101(20):e2043-e2045.
5. Li Q, Abdalkader M, Siegler JE. Mechanical thrombectomy for large ischemic stroke: a systematic review and meta-analysis. Neurology. 2023 Aug 29;101(9):e922-e932.
6. Yoshimura S, Uchida K, Sakai N, et al. Randomized clinical trial of endovascular therapy for acute large vessel occlusion with large ischemic core (RESCUE-Japan LIMIT): rationale and study protocol. Neurol Med Chir (Tokyo). 2022 Mar 15;62(3):156-164.