Acute Stroke Treatment in Patients with Basilar Artery Occlusion: A Single-Center Observational Study

Abstract

Background: Acute ischemic stroke (AIS) due to basilar artery occlusion (BAO) represents 1-4% of all ischemic strokes. BAO results in strokes associated with a high risk of a poor functional outcome and, in 86-95% of the untreated cases, it results in death because of the vital cerebral structures involved. Diagnosis can be delayed because of the variability in presenting symptoms, and acute treatment is often attempted even beyond 6 h from symptoms onset because of the high risk of a fatal prognosis.

Objective: In this observational study, we retrospectively analyzed patients with AIS due to BAO referred to the stroke center of the University Hospital of Messina. We aimed to assess prognostic factors and to evaluate the association between clinical outcome and posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) and collateral status.

Method: BAO was confirmed by cerebral computed tomography (CT) angiography or cerebral angiography. All patients underwent CT scan and magnetic resonance imaging (MRI). We assessed the pc-ASPECTS on diffusion-weighted imaging (DWI) MR images and the Posterior Circulation Collateral Score (PC-CS) for every patient. Functional outcome was assessed at 3 months using the modified Rankin Scale (mRS).

Results: The study population consisted of 27 patients; 16 males and 11 females. The mean age was 66 (±14) years. We observed a favorable outcome (mRS 0-3) in 40.7% of cases, 25.9% reached mRS 0-2, and 29.6% had a poor clinical outcome (mRS 4-5). Patient survival was 70.4%, whereas 8 patients died (29.6%). In 7 patients, pc-ASPECTS was ≥7. According to the PC-CS, 33.3% had moderate collaterals and 63.0% had good collateral status prior to receiving the treatment. Favorable outcome was significantly associated with age, NIHSS score at admission, pc-ASPECTS, hypercholesterolemia, and female sex but not with the other risk factors.

Conclusions: In our study, we found that younger age, low NIHSS score at admission, and high pc-ASPECTS, but not onset to treatment time, are associated with a favorable clinical outcome. Transferred patients did not have a significantly poorer outcome. These findings confirm that acute stroke treatment improves clinical outcome in BAO patients, in spite of a delayed diagnosis and an extended therapeutic window, considering lesion volume and localization in DWI MRI.

Keywords: Acute ischemic stroke; Basilar artery occlusion; Collateral circulation; Posterior circulation ASPECTS.