Mechanical thrombectomy for acute posterior cerebral artery stroke; Feasibility and predictors of outcome

The territorial involvement and the clinical benefit of endovascular therapy (EVT) of the posterior cerebral artery (PCA) occlusion may vary between patients. The purpose of this study was to investigate the feasibility of mechanical thrombectomy (MT) in isolated posterior cerebral artery occlusions (IPCAOs) and the prognostic factors of EVT.

Forty-eight patients with acute PCA occlusion who underwent EVT between Mar 2008 and Apr 2021 from 2 tertiary centers were retrospectively analyzed. Clinical characteristics, imaging and perfusion abnormalities, and angiographic and clinical outcomes were analyzed. Ischemic changes were assessed with the posterior circulation Acute Stroke Prognosis Early Computed Tomography Score (pc-ASPECTS). Perfusion abnormalities were assessed using automated software for Tmax volume measurement and identification of Tmax involved in PCA eloquent areas.

The IPCAO sites were P1 (n = 17) and P2 (n = 31). Overall successful recanalization (mTICI 2b/3) was achieved in 68.8% (33/48) and excellent outcome (90-day mRS 0-1) in 52.1% (25/48) of the patients. Excellent/non-excellent outcome was associated with male sex (p = 0.036), admission NIHSS (p = 0.002), pc-ASPECTS (p = 0.035), Tmax > 6 s involvement of the midbrain-thalamus (p = 0.008), first-line stent-retriever thrombectomy (p = 0.036), complete recanalization (p = 0.009), and modified first pass effect (FPE, p = 0.047). Tmax>6 s involvement of the midbrain-thalamus was an independent predictor for non-excellent outcome on multivariable analysis.

Acute stroke from IPCAO may be successfully treated with EVT. Tmax > 6 s involvement of the midbrain-thalamus on perfusion imaging may be a predictor for clinical outcome.