1 Department of Neurology, Inselspital, University Hospital Bern and University of Bern, Bern, Switzerland.
Brain. 2013 Dec;136(Pt 12):3554-60. doi: 10.1093/brain/awt246. Epub 2013 Sep 24.
The goal of acute stroke treatment with intravenous thrombolysis or endovascular recanalization techniques is to rescue the penumbral tissue. Therefore, knowing the factors that influence the loss of penumbral tissue is of major interest. In this study we aimed to identify factors that determine the evolution of the penumbra in patients with proximal (M1 or M2) middle cerebral artery occlusion. Among these factors collaterals as seen on angiography were of special interest. Forty-four patients were included in this analysis. They had all received endovascular therapy and at least minimal reperfusion was achieved. Their penumbra was assessed with perfusion- and diffusion-weighted imaging. Perfusion-weighted imaging volumes were defined by circular singular value decomposition deconvolution maps (Tmax > 6 s) and results were compared with volumes obtained with non-deconvolved maps (time to peak > 4 s). Loss of penumbral volume was defined as difference of post- minus pretreatment diffusion-weighted imaging volumes and calculated in per cent of pretreatment penumbral volume. Correlations between baseline characteristics, reperfusion, collaterals, time to reperfusion and penumbral volume loss were assessed using analysis of covariance. Collaterals (P = 0.021), reperfusion (P = 0.003) and their interaction (P = 0.031) independently influenced penumbral tissue loss, but not time from magnetic resonance (P = 0.254) or from symptom onset (P = 0.360) to reperfusion. Good collaterals markedly slowed down and reduced the penumbra loss: in patients with thrombolysis in cerebral infarction 2 b-3 reperfusion and without any haemorrhage, 27% of the penumbra was lost with 8.9 ml/h with grade 0 collaterals, whereas 11% with 3.4 ml/h were lost with grade 1 collaterals. With grade 2 collaterals the penumbral volume change was -2% with -1.5 ml/h, indicating an overall diffusion-weighted imaging lesion reversal. We conclude that collaterals and reperfusion are the main factors determining loss of penumbral tissue in patients with middle cerebral artery occlusions. Collaterals markedly reduce and slow down penumbra loss. In patients with good collaterals, time to successful reperfusion accounts only for a minor fraction of penumbra loss. These results support the hypothesis that good collaterals extend the time window for acute stroke treatment.
急性脑卒中治疗的目标是通过静脉溶栓或血管内再通技术来挽救缺血半暗带组织。因此，了解影响缺血半暗带组织损失的因素具有重要意义。在这项研究中，我们旨在确定影响大脑中动脉近端（M1 或 M2）闭塞患者缺血半暗带演变的因素。其中，血管造影上的侧支循环特别受关注。本分析纳入了 44 名患者，他们均接受了血管内治疗，至少实现了最小程度的再灌注。通过灌注和弥散加权成像评估他们的缺血半暗带。通过圆形奇异值分解反卷积图（Tmax＞6 s）定义灌注加权成像体积，并将结果与未反卷积图（达峰时间＞4 s）获得的体积进行比较。缺血半暗带体积的损失定义为治疗后弥散加权成像体积与治疗前体积的差值，并以治疗前缺血半暗带体积的百分比表示。使用协方差分析评估基线特征、再灌注、侧支循环、再灌注时间与缺血半暗带体积损失之间的相关性。侧支循环（P = 0.021）、再灌注（P = 0.003）及其相互作用（P = 0.031）独立影响缺血半暗带组织的损失，但与从磁共振成像（P = 0.254）或从症状发作（P = 0.360）到再灌注的时间无关。良好的侧支循环明显减缓并减少缺血半暗带的损失：在脑梗死溶栓 2b-3 级再灌注且无任何出血的患者中，0 级侧支循环下缺血半暗带损失 27%，血流速度为 8.9 ml/h，1 级侧支循环下损失 11%，血流速度为 3.4 ml/h。2 级侧支循环下缺血半暗带体积变化为-2%，血流速度为-1.5 ml/h，表明弥散加权成像病变完全逆转。我们得出结论，侧支循环和再灌注是决定大脑中动脉闭塞患者缺血半暗带组织损失的主要因素。侧支循环明显减少和减缓了缺血半暗带的损失。在侧支循环良好的患者中，成功再灌注的时间仅占缺血半暗带损失的一小部分。这些结果支持这样一种假设，即良好的侧支循环延长了急性脑卒中治疗的时间窗。
