Microbleeds, cerebral hemorrhage, and functional outcome after endovascular thrombectomy

<p><b>Objective</b>—To determine <span>whether the presence, number, and distribution of cerebral microbleeds (CMBs) on </span>pretreatment MRI <span>scans are associated with an increased risk of intracerebral hemorrhage (ICH) or poor functional outcome </span>following <span>endovascular thrombectomy (EVT)</span> for <span>acute ischemic stroke (AIS).</span></p> <p><b>Methods</b>—We analyzed prospectively collected data of consecutive patients treated by <span>EVT</span> for AIS, in a comprehensive stroke center where MRI is the first-line pretreatment imaging. Neuroradiologists blinded to clinical data rated CMBs on T2* sequence using a validated scale. <span>We investigated associations of pre-treatment CMB presence, burden (1, 2–4, and ≥5), and presumed pathogenesis with ICH and poor 3-month functional outcome (modified Rankin score &gt;2)</span>.</p> <p><b>Results</b>—Among 513 patients, <span>281 (54.8%) had a poor outcome</span> and 89 (17.3%) had ≥1 CMBs. <span>A total of 190 (37%) patients experienced ICH, in which 66 (12.9%) were symptomatic. </span>CMB burden was associated with worse outcome in a univariable analysis (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.03–1.36 per 1-CMB increase; P=0.02), but significance was lost after adjustment for age, sex, baseline stroke severity, hypertension, <span>diabetes mellitus</span>, atrial fibrillation, prior antithrombotic medication, intravenous thrombolysis, and reperfusion status (OR, 1.05; 95% CI, 0.92–1.20 per 1-CMB increase; P=0.50). Results remained nonsignificant when taking into account CMB location or presumed underlying vasculopathy. CMB presence, burden, location, nor presumed underlying vasculopathy was independently associated with ICH.</p> <p><b>Conclusions</b>—Poor outcome or ICH was not associated with CMB presence or burden on pre–EVT MRI after adjustment for confounding factors. Excluding such patients from reperfusion therapies is unwarranted.</p>