Mechanical thrombectomy for acute ischemic stroke in the posterior circulation: assessment of efficacy and outcome and identification of prognostic factors.

Background: Mechanical thrombectomy (MT) is well-established in the treatment of acute ischemic anterior circulation stroke. However, there is no evidence from randomized trials or meta-analyses that MT is safe and effective in the treatment of patients with acute ischemic posterior circulation stroke (PCS).
Purpose: To evaluate the clinical and procedural factors associated with recanalization and outcome of patients with PCS treated with MT.
Material and Methods: Forty-three patients with PCS (median age 73 years) who underwent treatment with MT were included. Data including demographics, baseline stroke severity, radiological imaging, procedure and post-procedure complications were documented. Clinical outcome was evaluated using the modified Rankin Scale (mRS). The patients were classified into two groups based on clinical outcome (favorable vs. unfavorable mRS after 90 days).
Results: Median baseline National Institute of Health Stroke Scale (NIHSS) was 17. Twenty patients were eligible for intravenous thrombolysis and received recombinant tissue plasminogen activator before MT. Successful recanalization was observed in 88.4% of patients. After 90 days, favorable outcome (defined as mRS 0-2) was achieved in 26 patients; six patients had an unfavorable outcome (mRs >2). Final mortality rate was 25.5%. Baseline NIHSS, onset to reperfusion time, procedure duration, and successful recanalization had a statistically significant association with outcome. Failed recanalization and occurrence of intracranial hemorrhage were found to be associated with a higher mortality rate.
Conclusion: MT is feasible and effective method in treatment of PCS. Baseline NIHSS and onset to reperfusion time were found to be independent predictive factors of clinical outcome.