Impact of Initial Diffusion-Weighted Imaging Lesion Growth Rate on the Success of Endovascular Reperfusion Therapy

Background and purpose: Initial diffusion-weighted imaging lesion growth rate (IGR) assessed by diffusion-weighted imaging lesion volume divided by the delay from onset to magnetic resonance imaging offers an estimate of early brain infarction progression. We investigated the impact of IGR on the rate of favorable outcome according to the occurrence of a successful endovascular revascularization within 6 hours after onset in patients experiencing an acute brain infarction complicating internal carotid artery terminus/middle cerebral artery M1 occlusion.

Methods: The primary study end point was a favorable outcome defined by a modified Rankin Scale score of ≤2, 90 days after onset. A Thrombolysis in Cerebral Infarction score 2b/3 defined a successful recanalization.

Results: A total of 166 patients were included. Median IGR was 7 mL/h (interquartile range, 2-26). Sixty-eight patients (41%) experienced a favorable outcome. After adjustment on age, systolic blood pressure, vessel site occlusion, National Institutes of Health Stroke Scale, and antithrombotic medication, increase in IGR was associated with a decreased occurrence of favorable outcome with an odds ratio per SD increase of 0.60 (95% confidence interval, 0.38-0.94; P=0.03). A successful recanalization was achieved among 56% of the patients after a median delay of 251 minutes (interquartile range, 211-291 minutes). Increasing IGR was associated with a decreased favorable outcome only when a successful recanalization was not achieved (adjusted odds ratio, 0.32; 95% confidence interval, 0.12-0.85; P=0.02).

Conclusions: Proximal internal carotid artery/M1 occlusion did result into a wide range of IGR within 6 hours after onset. Increasing IGR was associated with a lower rate of favorable outcome after endovascular treatment overall and when a successful recanalization was not achieved.