Relevance of peripheral inflammation indexes in different collateral circulation for intracranial hemorrhage in acute anterior circulation ischemic stroke patients undergoing endovascular treatment.

Background: Asymptomatic intracranial hemorrhage (aICH) is common after endovascular thrombectomy (EVT). Collateral circulation could modify the association between aICH with functional outcome and we aimed to investigate the impact of systemic inflammation index on 3-month outcome under different collateral circulation.

Method: Consecutive patients undertaken EVT were enrolled and classified into non-intracranial hemorrhage (non-ICH), aICH and symptomatic intracranial hemorrhage (sICH) groups according to the neurological status and National Institutes of Health Stroke Scale (NIHSS) changes within 72 hours after EVT. Preoperative collateral status was scored using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale. Clinical data were collected and analyzed according to the stratification of collateral stratification. Multivariate regression models were constructed to evaluate the influence of systemic inflammation indexes and collateral status on functional outcome.

Results: Of 302 patients, 86 (28.5%) developed aICH with 36(11.9%) sICH. Compared to non-ICH patients, there was a significant trend towards higher proportion of poor collateral circulation in patients with aICH, sICH (47.8% vs. 67.2% vs. 94.4%, p <0.001). Spearman's correlation analysis revealed a significant negative correlation of peripheral neutrophil counts, NLR, and SIRI with collateral circulation score. Under poor collateral circulation, neutrophil counts showed a significant positive association with sICH (OR 1.20, 95%CI: 1.07-1.35, p=0.002), but not with aICH. Under good collateral circulation, the inflammation indexes did not show a significant correlation with either ICH.

Conclusion: aICH patients with good collateral circulation have good functional outcome comparable to no-ICH patients. Under poor collateral circulation, elevated neutrophil counts may contribute to the conversion from aICH to sICH. Tailored anti-inflammatory therapy has potential to improve the efficacy and safety of EVT.