Development of imaging-based risk scores for prediction of intracranial haemorrhage and ischaemic stroke in patients taking antithrombotic therapy after ischaemic stroke or transient ischaemic attack: a pooled analysis of individual patient data from cohort studies

SPS commentary:

According to a commentary, a high cerebral microbleed count and high MICON-ICH score probably does not preclude antithrombotic treatment for nearly all the patients with transient ischaemic attack or ischaemic stroke (IS) analysed in MICON in whom, despite antithrombotic use, IS risk exceeded intracranial haemorrhage (ICH) risk. However, it acknowledges that weighing overall risks against benefits of antithrombotics is complex, requiring a calculation of not only IS and ICH incidence but also clinical severity of IS versus ICH (typically worse for ICH), and the relative effects of antithrombotic drugs on the incidence and severity of both stroke types. It notes that on the basis of the randomised RESTART study, the risk of ICH posed by antiplatelet therapy appears low, even in individuals with previous ICH, offering reassurance that antiplatelets can be safely used in most situations in which there is a defined indication. It adds however, that the stakes are higher for use of anticoagulants in patients at risk for ICH because of the large increases in ICH incidence and severity associated with anticoagulation. Furthermore, challenging decision of whether to use anticoagulants in individuals with both indications for anticoagulation, such as non-valvular AF, and risks, such as previous ICH, has triggered multiple ongoing RCTs. It also points out that as the direct oral anticoagulants consistently show lower ICH risk than vitamin K antagonists, warfarin is not a rational option in this situation and all ongoing trials are testing direct oral anticoagulants.