Combined Multimodal Computed Tomography Score Correlates With Futile Recanalization After Thrombectomy in Patients With Acute Stroke

Recanalization is strongly associated with improved functional outcomes and reduced mortality in patients with acute stroke, but reopening of large arteries may not achieve effective tissue reperfusion, may occur too late, or even may exacerbate tissue injury by reperfusion phenomenon. The so-called futile recanalization concept refers to those patients who present poor clinical outcomes despite an adequate vessel recanalization. Although the mechanical thrombectomy devices and reperfusion techniques in acute ischemic stroke keep rapidly evolving and achieve higher recanalization rates, a significant number of successfully treated patients do not experience clinical improvement after thrombectomy. This fact has been related not only to several nonmodifiable factors, such as age, hypertension, stroke severity, proximal occlusion, and time from symptom onset, but also to the underestimation of the ischemic injury on conventional neuroimaging before thrombectomy. Relevant studies by experienced neurovascular groups have shown the added value of advanced neuroimaging in showing the extension of the ischemic lesion. Despite these facts, many interventional neuroradiologists still do not take into account the relevant information that can be achieved Background and Purpose—Futile recanalization after acute ischemic stroke occurs in almost half of the patients despite optimal angiographic results. Multimodal neuroimaging may help to improve patient’s selection but is still dismissed by many interventionalists. Our aim was to evaluate the accuracy of each parameter of multimodal computed tomography (CT) and their combination for predicting futile recanalization after successful thrombectomy. Methods—We retrospectively reviewed a cohort of consecutive patients with anterior circulation stroke, fully assessable multimodal CT, and successful recanalization. Nonenhanced CT, CT angiography source images, cerebral blood volume (CBV), cerebral blood flow (CBF), and mismatch CBV–CBF maps were studied by Alberta Stroke Program Early CT Score (ASPECTS); collaterals on CT angiography were graded as poor or good (≤50% or >50% of the middle cerebral artery territory). Futile recanalization was defined as modified Rankin Scale score >2 at 3 months despite successful recanalization. Results—One hundred fifty patients were included and 57% of them had futile recanalization. They had lower ASPECTS on nonenhanced CT, CT angiography source images, CBV, CBF, and mismatch CBV–CBF and presented more frequently poor collaterals (all P<0.001). Among them, CBV showed the highest area under the curve (0.83; 95% confidence interval, 0.76–0.88). In multivariate analyses, CT angiography source images ≤5 (odds ratio, 5.1; 95% confidence interval, 1.2– 21.9), CBV≤6 (odds ratio, 3.5; 95% confidence interval, 1.2–9.7), and poor collaterals (odds ratio, 8.6; 95% confidence interval, 1.8–41.7) were independent predictors of futile recanalization. A combined score of these 3 parameters added complementary information: 57% of the patients with score-1, 89% with score-2, and 100% with score-3 had futile recanalization. Reclassification analyses indicated that this score improved prediction of futile recanalization. Conclusions—In this population, a combined multimodal CT score predicted futile recanalization. (Stroke. 2015;46:00-00. DOI: 10.1161/STROKEAHA.114.008598.)