Influence of dehydration on collateral circulation and clinical outcome after endovascular therapy in patients with acute ischemic stroke.

Introduction: Dehydration in patients with acute ischemic stroke (AIS) is associated with poor outcome. Our aim is to investigate whether dehydration is associated with collateral circulation (CC) and functional outcome in patients with AIS treated with mechanical thrombectomy (MT).

Methods: Prospective multicenter study of patients with anterior circulation AIS treated with MT (January 2020-June 2021). Dehydration was assessed with two formulas: plasma osmolarity and urea/creatinine (U/C) ratio. CC was quantified with an automated software (Brainomix Ltd.) on baseline computed tomography angiography. The primary outcome was the association between CC (expressed numerically as the percentage of change between hemispheres) and dehydration (osmolarity ≥295mmol/L, U/C ≥ 80). Secondary outcomes included disability at discharge and at three months of follow-up, assessed using the modified Rankin scale (poor outcome: 3-6). Multivariable logistic and ordinal regression analyses were performed.

Results: Two hundred sixty patients were included. 65.8% were dehydrated according to osmolarity and 2.9% according to U/C. There was no association between CC score and dehydration [71% in dehydrated vs 73% in non-dehydrated; p = 0.875]. 64.3% of dehydrated patients vs. 46.7% of non-dehydrated patients had a poor outcome at discharge (p = 0.026). In multivariable logistic regression analysis, dehydration was an independent predictor of poor outcome at discharge (OR 2.50; p = 0.011) and at three months of follow-up (OR 2.27; p = 0.046).

Conclusions: Dehydration on admission is associated with poor outcome in patients with AIS treated with MT, but it is not related to CC.