Abstract TP106: Cerebral Microhemorrhages and the Risk of Symptomatic Intracerebral Hemorrhage After Intravenous Thrombolysis

Abstract

Introduction and Background: Cerebral microhemorrhages/microbleeds (CMBs) are proposed to increase the risk of thrombolysis-related hemorrhage. This may be because A) they are a marker of cerebral small vessel disease (a known risk factor for hemorrhagic transformation) and B) they are a feature of cerebral amyloid angiopathy (CAA). We sought to understand the relationship between CMB burden and risk of symptomatic intracerebral hemorrhage after intravenous thrombolysis in our institution. Methods: We undertook a retrospective observational study of patients who had received intravenous thrombolysis for presumed acute ischemic stroke. Patient information was gathered including demographics, past medical history, treatment and ischemic stroke subtype. T2*/GRE imaging was inspected and the presence or absence, number and distribution of definite CMBs (according to Microbleed Anatomic Rating Scale (MARS) criteria) was documented for each patient. Results: Four hundred and twenty five patients were identified who had received IV tPA during our study period of whom 90 (21.2%) had evidence of CMBs on T2*/GRE imaging. Three patients (3.3%) with CMBs had symptomatic intracranial hemorrhage compared with 7 (2%) of those without CMBs (p=0.49). The mean number of CMBs in those with tPA-related hemorrhage was 0.30 while in those without sICH was 0.84. 12 patients had greater than 5 microhemorrhages and in that group 0 patients had tPA-related hemorrhage. Three of the 12 cases with >5 microhemorrhages met modified Boston criteria for probable CAA. Discussion: In contrast to other reports, we found no association between either presence or number of CMBs and sICH. The subgroup of patients with >5CMBs also did not demonstrate an increased risk. Our study was limited by the low numbers of sICH observed. The presence of CMBs may correlate with other variables that decreased the likelihood of tPA being administered such as presence of prior intracerebral hemorrhage or CAA.