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.