Cerebral microbleeds and prediction of intracranial haemorrhage

The 18th century Japanese monk Hakuin Ekaku posed the philosophical riddle: "what is the sound of one hand clapping?". This traditional Zen koan comes to mind when contemplating the stroke prevention literature, in which the weighing of risk of ischaemic stroke against risk of intracranial haemorrhage has been a somewhat one-sided affair. The risk of ischaemic stroke in patients with underlying conditions, such as nonvalvular atrial fibrillation, has been extensively studied, yielding widely used scales with at least moderate predictive value, such as the CHA2DS2-VASc and ATRIA scores. 1 Zhu W Fu L Ding Y et al. Meta-analysis of ATRIA versus CHA2DS2-VASc for predicting stroke and thromboembolism in patients with atrial fibrillation. Int J Cardiol. 2017; 227: 436-442 Summary Full Text Full Text PDF PubMed Scopus (15) Google Scholar Conversely, scales developed for risk of major bleeding, such as HAS-BLED, appear to have low ability to predict intracranial haemorrhage or discriminate between risk of ischaemic stroke and intracranial haemorrhage. 2 Jaakkola S Kiviniemi TO Nuotio I et al. Usefulness of the CHA2DS2-VASc and HAS-BLED scores in predicting the risk of stroke versus intracranial bleeding in patients with atrial fibrillation (from the FibStroke study). Am J Cardiol. 2018; 121: 1182-1186 Summary Full Text Full Text PDF PubMed Scopus (5) Google Scholar For the purpose of clinical decision-making regarding antithrombotic therapy after ischaemic stroke or transient ischaemic attack, it is reasonable to focus on risk of intracranial haemorrhage, rather than extracranial bleeding, because of the disproportionate burden of mortality and long-term disability attributable specifically to intracranial haemorrhage. 3 Fang MC Go AS Chang Y et al. Death and disability from warfarin-associated intracranial and extracranial hemorrhages. Am J Med. 2007; 120: 700-705 Summary Full Text Full Text PDF PubMed Scopus (388) Google Scholar 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 studiesThe MICON risk scores, incorporating clinical variables and cerebral microbleeds, offer predictive value for the long-term risks of intracranial haemorrhage and ischaemic stroke in patients prescribed antithrombotic therapy for secondary stroke prevention; external validation is warranted. Full-Text PDF