Abstract Number: Esoc2026a1262 Can Proximal Vessel Velocities Be Used to Rule Out Vasospasm in Patients With Aneurysmal Sah?

Abstract Background and aims Vasospasm is a feared complication of aneurysmal subarachnoid hemorrhage (aSAH). Patients are frequently monitored in intensive care units with daily transcranial doppler ultrasounds (TCD) for up to 21 days. Attempts to identify those at highest risk of vasospasm have not led to significant practice change. We sought to identify patients at lowest risk of vasospasm by testing the prognostic utility of novel low-risk criteria: mean velocities in the in the artery anatomically closest to the rupture site to remain below vasospasm velocity threshold by 7th day post-SAH. Methods We conducted a retrospective observational study using TCD readings from 200 patients admitted to The Ottawa Hospital from 2019-2024. We collected highest mean blood flow velocities in all vessels throughout the admission. Primary outcome was presence of vasospasm in any artery based on Solan’s criteria (MCA 120 cm/s, ICA 80 cm/s, ACA 90 cm/s, PCA 60 cm/s, BA 70 cm/s, VA 60 cm/s). Results Of 188 patients with aSAH, 111 met inclusion criteria, of whom 67 (60.3%) met our low-risk criteria. Among patient meeting the low-risk criteria, 22 (32.8%) developed the primary outcome (p0.001). The Negative Predictive Value (NPV) for vasospasm in our low-risk group was 67.2%. Conclusions Our low-risk criteria based on TCD patterns in the first 7 days since SAH can identify cohort of patients at lower risk of vasospasm in all major arteries. This study could inform future prospective studies testing early discharge from ICU in patients meeting our low-risk criteria as a cost-saving measure. Conflict of interest Sanaz Biglou: nothing to disclose Laurence Poirier: nothing to disclose Vincent Brissette: nothing to disclose Dar Dowlatshahi: nothing to disclose Célina Ducroux: nothing to disclose Michel Shamy: nothing to disclose