About antifragility and the challenge of dealing with endovascular therapy trials that fail to show a positive result

Endovascular therapy (EVT) is a highly effective treatment for acute ischemic stroke due to large vessel occlusion (LVO). Eight randomized controlled trials have proven its efficacy and safety in patients with LVO presenting within 24 hours.1–3 EVT eligibility criteria are likely to expand even further into the ‘fringes’, as more and more data on the safety and efficacy of EVT beyond current guideline recommendations become available—for example, for patients with M2 occlusions4 and those presenting more than 24 hours from last known well.5 In fact, it is becoming increasingly difficult to find a patient subgroup which does not benefit from EVT. While in the early days of EVT we were asking ourselves which patients to treat, the situation has now turned around; today, we ask ourselves which patients should not be treated.6 Physicians pursue a more and more aggressive treatment strategy: patient age, time from symptom onset, comorbidities, distal occlusion site, low Alberta Stroke Program Early CT Score (ASPECTS), and National Institutes of Health Stroke Scale (NIHSS) score do not discourage us from offering EVT .7 As an example, current guideline recommendations from the American Heart Association/American Stroke Association restrict level 1A treatment recommendations for EVT to patients with internal carotid artery and M1 occlusions, ASPECTS ≥6, and NIHSS score ≥6.8 However, in a recent international multidisciplinary survey with 607 physicians from 38 countries, most stated that they would offer EVT even in patients with further distal occlusions, and ASPECTS and NIHSS scores <6 (table 1).7 View this table: Table 1 Results from UNMASK EVT, an international multidisciplinary case based survey The scenario illustrated in figure 1 is not covered by currently established guidelines. Nevertheless, we and many others think that treating this patient was the right decision. The case clearly shows a dilemma that we encounter in our clinical practice …