Predictors of new remote cerebral microbleeds after IV thrombolysis for ischemic stroke

Objective To assess the frequency, associated factors, and underlying vasculopathy of new remote cerebral microbleeds (CMB), as well as the risk of concomitant hemorrhagic complications related to new CMBs, after IV thrombolysis (IVT) in acute stroke patients. Methods We conducted an observational study using data from our local thrombolysis registry. We included consecutive stroke patients with MRI (3T)-based IVT and a follow-up MRI the next day between 2008 and 2017 (n = 396). Only CMBs located outside of the ischemic lesions were considered. We also performed a meta-analysis on new CMBs after IVT that included 2 additional studies. Results In our cohort, new remote CMBs occurred in 16/396 patients (4.0%) after IVT and the distribution was strictly lobar in 13/16 patients (81%). Patients with preexisting CMBs with a strictly lobar distribution were significantly more likely to have new CMBs after IVT ( p = 0.014). In the random-effects meta-analysis (n = 741), the pooled cumulative frequency of new CMBs after IVT was 4.4%. A higher preexisting CMB burden (>2) was associated with a higher likelihood of new CMBs (odds ratio [OR] 3.6, 95% confidence interval [CI] 1.3–10.3) and new CMBs were associated with the occurrence of remote parenchymal hemorrhage (OR 28.8, 95% CI 8.6–96.4). Conclusions New remote CMBs after IVT occurred in 4% of stroke patients, mainly had a strictly lobar distribution, and were associated with IVT-related hemorrhagic complications. Preexisting CMBs with a strictly lobar distribution and a higher CMB burden were associated with new CMBs after IVT, which may indicate an underlying cerebral amyloid angiopathy.