Future trials on endovascular stroke treatment: the not-so-easy-to-pluck fruits

Physician, know thyself: implicit and explicit decision-making for mechanical thrombectomy in stroke

Few clinical situations in medical practice are as time-sensitive and and have such profound ramifications as selection of patients with acute stroke for mechanical thrombectomy (MT). Emergent large vessel occlusion has become a treatable disease with minimal numbers needed to treat to achieve a functional, long-term neurologic outcome. However, MT carries risk and many patients who are appropriately reperfused continue to have significant neurologic deficits and disability despite a successful procedure. The decision to offer or withhold MT can be complex. Frequently decisions must be made based on incomplete information or emergently while the physician is awoken from sleep or distracted while performing other procedures. A growing number of studies have examined cognitive errors and biases as they pertain to patient diagnosis and treatment in medicine. Dual process theory identifies two decision-making processes as system 1 ('implicit') and system 2 ('explicit') and describes the patterns through which decisions are formulated. The implicit system is the default pathway as it requires little effort or focus, uses mental short cuts, and is rapid; however, this pathway is subject to considerable bias and error. This manuscript reviews the mechanisms underlying the way in which physician decisions about MT are made, specifically highlighting prominent biases that may affect judgment, and reviews other important principles, such as confidence in decisions, aggressiveness to pursue MT, and strategies to improve decisions.

Stroke patients treated by thrombectomy in real life differ from cohorts of the clinical trials: a prospective observational study

Background

Randomized controlled trials (RCTs) demonstrated efficacy and safety of endovascular treatment (ET) in anterior circulation large vessel occlusions (LVO). We aimed at investigating how stroke patients treated by thrombectomy in clinical practice and their outcome compare to cohorts and results of thrombectomy trials.

Methods

In a prospective study, we consecutively included stroke patients treated by thrombectomy (2015–2017). Baseline characteristics, procedural and outcome data were analyzed. Outcome was assessed by modified Rankin Scale (mRS) at 90 days. Ordinal regression analysis was performed to identify predictors of outcome.

Results

Thrombectomy was applied in 264 patients (median 75 years, 49.6% female). Median baseline National Institutes of Health Stroke Scale (NIHSS) was 16, 58.0% received concomitant intravenous thrombolysis, 62.1% were referred from external hospitals. Median Alberta Stroke Program Early CT Score (ASPECTS) was 7. Successful recanalization (modified Thrombolysis in Cerebral Infarction Score, mTICI 2b/3) was achieved in 72.0%. Symptomatic intracranial hemorrhage (sICH) occurred in 4.5%. Independent outcome (mRS 0–2) was achieved in 26.2%, poor outcome (mRS 5–6) in 49.2%. Only 33.5% met the stringent enrolment criteria of previous RCTs. Lower age, baseline NIHSS, pre-stroke mRS, higher ASPECTS, and successful recanalization were independent predictors of favourable outcome.

Conclusions

The majority of stroke patients treated by ET in clinical practice would not have qualified for randomization in prior RCTs. Outcome in real-life patient cohorts is worse than in the highly selected cohorts from randomized trials, while rates of successful recanalization, sICH and outcome predictors are the same. Our findings support ET in broader patient populations than in the RCTs and may improve treatment decision in individual stroke patients with LVO in clinical practice.