Pre-Procedural Computed Tomography Angiogram for Patients Transferred for Thrombectomy: Can We Minimize Costs?

Patients with large vessel occlusion (LVO) stroke are often transferred from primary to tertiary stroke centres for endovascular thrombectomy (EVT). We previously showed that ≥33% improvement in National Institute of Health Stroke Scale (NIHSS) score correlated with early recanalization, obviating the need for EVT. We aimed to validate this correlation and assess cost savings if non-invasive imaging was performed prior to digital subtraction angiography (DSA).

Patients transferred to an Australian tertiary stroke centre for possible EVT between January 2023 and April 2024 and underwent DSA with or without EVT were included. Changes in NIHSS between transfer and arrival, demographic, treatment, and anatomical factors were collected. NIHSS changes were correlated with early recanalization. Real-time costs of in- and out-of-hours neuroimaging and DSA were calculated.

A total of 257 transferred patients with LVO were included (30% female, median age 71 [IQR 61-79]). The median presentation NIHSS was 14 (IQR 10-19). A total of 129 (50%) patients received intravenous thrombolytics. Twenty-seven (11%) patients demonstrated early recanalization and did not require EVT. Threshold of ≥33% NIHSS improvement remained the best trade-off between sensitivity (74%) and specificity (88%) for recanalization. The hyperacute investigation and treatment costs in/out-of-hours per patient were AUD 1,491 and AUD 3,591. Costs if patients with ≥33% NIHSS improvement were non-invasively imaged prior to DSA were AUD 1,471 and AUD 3,548 - savings of AUD 34 per patient overall.

We validated that ≥33% neurological recovery between primary and tertiary stroke centre had the best sensitivity-specificity profile for predicting early recanalization. Modest cost savings occurred using this threshold, but in resource-poor settings, this may be more significant.