Early stellate ganglion block for improvement of postoperative cerebral blood flow velocity after aneurysmal subarachnoid hemorrhage: results of a pilot randomized controlled trial

Stellate ganglion block (SGB) is a commonly used sympathetic nerve block technique that may have benefits for patients with aneurysmal subarachnoid hemorrhage (aSAH) in the early stage. Cerebral vasospasm (CVS), one of the most common complications of aSAH, is accompanied by an abnormal increase in cerebral blood flow velocity (CBFV) and neurological dysfunction. In this pilot study the authors sought to determine the feasibility of early SGB for CVS in aSAH patients by observing the incidence of symptomatic CVS. Prior to receiving surgical treatment, patients with aSAH were randomly assigned to the SGB group or the non-SGB group. The primary outcome was the incidence of symptomatic CVS within 14 ± 2 days after the onset of aSAH. As a higher CBFV is often associated with CVS and a poor prognosis, the mean CBFV of the middle cerebral artery was observed immediately after surgery and on postoperative days 1, 2, 3, 5, and 7. Other secondary outcomes included transcranial Doppler (TCD)/CTA-type CVS, delayed cerebral ischemia during hospitalization, new cerebral infarction within 3 months, adverse events (AEs), and clinical prognosis. Symptomatic CVS occurred in 40% of patients in the non-SGB group and in 20% in the SGB group (RR 0.50, 95% CI 0.22-1.16). Continuous TCD sonography revealed that the postoperative mean CBFV was lower in the SGB group than in the non-SGB group (F = 3.608, p = 0.02). In addition, the percentages of patients with CVS evaluated by TCD (TCD-CVS) and total new infarctions within 3 months were also significantly lower than those in patients with CVS (TCD-CVS 36.7% vs 70%, RR 0.52, 95% CI 0.31-0.89, and total new infarctions 26.7% vs 53.3%, RR 0.50, 95% CI 0.25-0.99). In terms of AEs and mortality, there were no significant differences between the two groups. This pilot study demonstrated for the first time, to the authors' knowledge, that early SGB is feasible and has the potential to reduce the risk of CVS and improve the prognosis of aSAH. This method may be a new treatment for patients with aSAH that may have more advantages than traditional therapeutic drugs and is worth further study. Clinical trial registration no.: NCT04691271 (ClinicalTrials.gov).