Peggy Nguyen, MD

Yoon W, Kim SK, Heo TW, Baek BH, Lee YY, and Kang HK. Predictors of Good Outcome After Stent-Retriever Thrombectomy in Acute Basilar Artery Occlusion. Stroke. 2015

Within the past year, the landscape of ischemic stroke treatment has rapidly changed with the publications of multiple positive trials of endovascular treatment. Thrombectomy has quickly been incorporated into the comprehensive care of the ischemic stroke patient; however, data regarding thrombectomy in patients with posterior circulation strokes, specifically basilar artery occlusions, remains uncertain. The major endovascular trials largely included those with anterior circulation strokes, namely ICA and MCA occlusions, with evidence being the strongest for causative occlusions of the ICA or M1. To address this deficit in our clinical knowledge, the authors here performed a retrospective analysis of patients with basilar occlusion strokes with the goal of identifying predictors of good outcome following endovascular therapy.

Of 50 consecutively enrolled patients in their comprehensive stroke center with basilar occlusion strokes who underwent mechanical thrombectomy, 54% (27/50) achieved a good outcome, considered as a modified Rankin scale of ≤ 2 at 3 month follow up, with mortality being 12% (6/50) at 3 months. There were no instances of symptomatic hemorrhage during the hospitalization. Authors identified two variables which independently predicted good outcomes: (1) a low initial stroke severity, defined by baseline NIHSS and (2) a high posterior circulation-ASPECTS (the pc-ASPECTS scoring system has previously been published elsewhere, see Puetz, et al. Stroke 2008) on pretreatment MRI-DWI sequence. Notably, no patients with a pc-ASPECTS of 3-5 (n=7) had a good outcome at 3 months while all patients with a pc-ASPECTS of 9 (n=6) had a good outcome. When dichotomized into groups with pc-ASPECTS ≥ 7 versus those < 7, patients with pc-ASPECTS ≥ 7 had a significantly higher rate of good outcome (66.7% vs 29.4%). Other variables which were associated with good outcome in univariate analysis were young age, absence of hypertension, and absence of bilateral thalamic infarction.

The most updated AHA/ASA guidelines only state that although the benefits are uncertain, use of endovascular therapy with stent retrievers may be reasonable for certain patients with a causative basilar occlusion, but criteria for selection are still unclear. Although it may vary from institution to institution, in our large urban academic center, the ASPECTS score is calculated on all ischemic stroke patients presenting for possible thrombectomy, but the pc-ASPECTS score has not been largely utilized. Although there are some limitations to this study, including the retrospective, non-controlled design, and the small number of patients, this along with other studies may prompt me to start thinking about a pc-ASPECTS score on my patients when they pass through the door to intervention.