One Treatment to Heal them all: Thrombectomy also Benefits Stroke with Large Ischemic Core

Excerpt

Thrombectomy has revolutionized stroke treatment worldwide, improving the outlook for severe stroke with a treatment success previously unheard of in acute stroke treatment. Following the Dutch MR CLEAN trial [1], a series of clinical trials has demonstrated the benefit of endovascular thrombectomy (EVT) for patients with large vessel occlusion. In the pooled HERMES analysis of the “first wave” of stroke thrombectomy trials, the number needed to treat with thrombectomy to reduce disability by at least 1 level on the modified Rankin scale (mRS) at 90 days for 1 patient was as low as 2.6 [2]; however, in most of these trials enrolment excluded patients with large ischemic core, either based on the visual assessment of pre-treatment Alberta Stroke Program Early CT score (ASPECTS) or by quantification of the ischemic core using perfusion CT. Moreover, in the early trials the majority of patients were treated within the first 6 h of known symptom onset. As a result, most international guidelines adopted the recommendation for treatment with thrombectomy for large vessel occlusion within the first 6 h guidelines for patients with no signs of extended infarction, usually operationalized by an ASPECTS of ≥ 6. It took no longer than another 2 years until two further groundbreaking trials of stroke thrombectomy were published that challenged the strict time window: both, DAWN and DEFUSE‑3 randomized patients in a late time window up to 16 or 24 h after known onset or those with unknown time of symptom onset to treatment with EVT or usual care, if patients had a perfusion mismatch (DEFUSE-3) [3], or a mismatch between a severe clinical deficit and only a small infarct core (DAWN) [4]. In these highly selected patients, the treatment effect of EVT was even stronger than in previous trials but again, and on purpose, patients with already large ischemic infarcts were excluded from both trials. Therefore, until recently, the main open question regarding thrombectomy for stroke remained whether EVT is effective or useless in patients with already extensive ischemic stroke lesions. This question is answered now. …