Berkhemer OA, Jansen IGH, Beumer D, Fransen PSS, van den Berg LA, Yoo AJ, et al. Collateral Status on Baseline Computed Tomographic Angiography and Intra-Arterial Treatment Effect in Patients With Proximal Anterior Circulation Stroke. Stroke. 2016
In this post-hoc analysis of the MR CLEAN study, collaterals were graded on baseline CTA using a 4-point scale where 0 was absent, 1 for poor (>0% and ≤50% filling of the occluded territory), 2 for moderate (> 50% and < 100% filling of the occluded territory), and 3 for good collaterals (100% filling of the occluded territory). There was an independent and significant modification of the treatment effect on the primary outcome of shift in direction of better outcome on the mRS. In addition, there was a shift in the distribution on the mRS in favor of intervention across all collateral grades except those with grade 0; the strongest shift was in patients with grade 3 collaterals. Patients with grade 3 collaterals had a 29.5% absolute increase in the chance of becoming functionally independent at day 90 (mRS 0-2), whereas in patients with grade 0 collaterals, none of the patients achieved functional independence at day 90.