Cerebral microbleeds (CMB) is a predictive factor of intracerebral haemorrhage (ICH) and patients with CMB under antithrombotics are at higher risk of ICH. Thus, the impact of anticoagulants and/or antiplatelets on the occurrence of ICH and/or on new CMB development is a major issue.

We aimed to evaluate the early progression at 3months of CMB and their predictive factors in patients with acute myocardial infarction (AMI) treated with direct oral anticoagulant (DOA) or vitamin K antagonist (VKA).

Prospective study from November 2016 to December 2018, including patients>60y hospitalized in intensive cardiac care unit for AMI. They underwent a first brain MRI (T2* gradient echo and SWI magnetic susceptibility image) <72hours after admission, and repeated 3months after stenting.

One hundred and eight patients (42women and 66men, mean age 77years) were included. Among the patients with CMB (21%), 66patients received a cerebral MRI at 3months after AMI. An increase in CMB number was observed for 6% of patients. These patients were older than those without CMB progression (85±5 vs. 75±8y, P=0.016) and were more often treated by DOA or VKA at hospital discharge than patients with unchanged CMB number:OR=15.6 [1.470–165.582]. In multivariate analysis, only discharge treatment with DOA or VKA was a predictive factor of CMB progression 3M after AMI:OR=13.8 [1.11–173.5]. No significant differences between the two groups with regard to CRUSADE and BLEEDING Risk haemorrhage scores were noted. Neither ICH nor ischemic stroke were observed.

MRI-detected CMB was common and may even early increase after AMI. Our results highlight that the association of DOA or VKA with dual antiplatelet therapy at hospital discharge could be an independent risk factor of CMB progression. Larger population studies are needed to address antiplatelet therapy duration and dose of DOA as potential risk factors for CMB progression.