Introduction Anemia has been associated with worse clinical outcomes and increased mortality following acute ischemic stroke, however, the study of anemia in acute ischemic stroke patients treated with mechanical thrombectomy has been limited.

Methods We performed a retrospective study of 346 anterior circulation stroke patients treated with mechanical thrombectomy to investigate the impact of peri-procedure anemia (Hgb <10 g/dL within 48 hours of admission) on outcomes and to determine the relationship between peri-procedure anemia and multiple thrombectomy passes/procedure time at a single Comprehensive Stroke Center from April 2012 to July 2019. Bivariate and multiple logistic regression analyses were performed. A p-value <0.05 was considered statistically significant.

Results One hundred patients (29%) met the criteria for peri-procedure anemia after admission for thrombectomy. Females comprised 73% of patients (n=73) with peri-procedure anemia compared to 39% (n=97) of patients without anemia (p<0.001). Peri-procedure anemia was associated with a longer thrombectomy procedure time (62.80 [3.89] min. vs. 54.38 [2.14]; p=0.044). There was a trend towards a greater number of thrombectomy passes among patients with peri-procedure anemia compared to those without anemia (p=0.058) on bivariate analysis. Peri-procedure anemia was associated with greater rates of poor functional outcome (73% vs. 54%; p=0.001) and death (35% vs. 18%; p=0.001). The final logistic regression model included the following variables: patient age, female sex, NIHSS, tPA, procedure time and number of thrombectomy passes. Among these variables, only female sex (OR 4.28, 95% CI 2.54–7.22; p<0.001) and ≥3 thrombectomy passes (OR 2.05, 95% CI 1.01–4.15; p=0.047) were independently associated with peri-procedure anemia after admission for thrombectomy (AUC=0.724).Several clinical factors were included in the final logistic regression model. Age (OR 1.03, 95% CI 1.00–1.05; p=0.015), history of diabetes (OR 1.90, 95% CI 1.07–3.37), admission NIHSS (OR 1.09, 95% CI 1.04–1.15; p<0.001) and peri-procedure anemia (OR 1.82, 95% CI 1.03–3.22; p=0.040) were independently associated with an increased odds of poor outcome. TICI grades 2C/3 (OR 0.18, 95% CI 0.08–0.40; p<0.001) were associated with a reduced odds of poor outcome. There was a trend towards an independent association between ≥3 thrombectomy passes and poor outcome (OR 1.80, 95% CI 0.94–3.45; p=0.078) although not statistically significant.

Conclusion Female sex and ≥3 thrombectomy passes were independently associated with peri-procedure anemia. Peri-procedure anemia was associated with worse clinical outcomes at 3-month follow-up. The interventional neuroradiologist should consider the potential adverse effects of peri-procedure anemia and minimize overall procedural blood loss when able, mainly in women that inherently have lower hemoglobin levels than men. Future studies are required to better understand the causal relationship between procedural blood loss and clinical outcomes following thrombectomy.

Disclosures H. Carvalho: None. A. Wessell: None. G. Cannarsa: None. T. Miller: None. D. Gandhi: None. G. Jindal: None.