The ASTRAL trial is a randomized study in patients with suspected stroke in the ambulance setting. The study evaluates whether prehospital telestroke consultation, in addition to standard care, can reduce unnecessary stroke code activations and improve patient triage, treatment efficiency, and resource use. Participants are randomized to telestroke triage plus standard care or standard care alone. Outcomes include unnecessary stroke code activation, patient allocation, treatment times, functional outcome, safety, and cost-effectiveness.

The Ambulance Stroke Triage Assisted by Telemedicine (ASTRAL) trial is a prospective, randomized controlled trial in suspected stroke patients attended by ambulance professionals in the RAV Hollands Midden region. Patients aged 18 years or older with stroke code activation during office hours and symptom onset within 24 hours are randomized 1:1 to telestroke triage plus standard care or standard care alone. The intervention consists of real-time video and audio consultation with an on-duty neurologist who advises on stroke probability, destination, and urgency of transport, while ambulance professionals retain final decision authority. The primary endpoint is unnecessary stroke code activation. Secondary endpoints include allocation accuracy, safety, door-to-needle and door-to-groin times, modified Rankin Scale at 3 months, health-related quality of life, healthcare utilization, stakeholder satisfaction, and cost-effectiveness. Outcome assessors for 3-month follow-up measures are blinded to allocation. Data are collected in Castor EDC, and analyses follow the intention-to-treat principle

Inclusion Criteria:

• Age 18 years or older
• Stroke code activation by ambulance professional during office hours
• Symptom onset < 24 hours or uncertain onset
• The patient is deemed capable of understanding the study information and making a decision about participation/opt-out

Exclusion Criteria:

- Age under 18 years

De-identified individual participant data (IPD) will be shared. The shared dataset will include variables needed to reproduce the primary and secondary analyses, such as baseline characteristics, treatment allocation, primary and secondary outcome variables, and key analysis covariates. Direct identifiers will not be shared. Data will be coded and pseudonymized.

IPD and supporting information will be available after publication of the primary results, beginning 6 months after publication and remaining available for 5 years.

Access will be granted to qualified researchers who submit a scientifically sound proposal. Requests will be reviewed by the study team or data access committee, if applicable. Access requires a data use agreement and, where applicable, institutional ethics approval. Only de-identified data necessary for the approved analysis will be shared.

The study is open-label for participants, ambulance professionals, and treating neurologists. Outcomes assessors for 3-month mRS and EQ-5D-5L assessments are blinded to treatment allocation