This prospective observational study aims to determine whether specific parameters measured by transcranial Doppler ultrasound (TCD) can predict clinical outcomes in patients with acute ischemic stroke (AIS). The primary objective is to evaluate the association between middle cerebral artery (MCA) flow velocities and short-term neurological improvement. Secondary outcomes include the presence of collateral flow and flow patterns in relation to functional recovery measured by NIHSS and modified Rankin Scale (mRS) scores.

TRADE-AIS (Transcranial Doppler Evaluation - Acute Ischemic Stroke) is a prospective, single-center, observational cohort study designed to evaluate the prognostic value of transcranial Doppler ultrasound (TCD) in patients with acute ischemic stroke (AIS). The study will be conducted at Clínica México, a secondary-level hospital located in Piedras Negras, Coahuila, Mexico.

Upon presentation to the emergency department or inpatient stroke unit, patients diagnosed with AIS will undergo a baseline neurological examination, including NIH Stroke Scale (NIHSS) scoring. A transcranial Doppler ultrasound will then be performed within 24 hours of symptom onset. The TCD protocol will include insonation of the middle cerebral arteries (MCAs), anterior and posterior communicating arteries, and basilar artery, using a 2-MHz probe via the temporal window.

Parameters to be recorded include:

Mean flow velocity (Vm) in the MCA

Pulsatility index (PI)

Presence and pattern of collateral flow (e.g., via anterior communicating artery)

Abnormal waveforms such as reverberant, absent, or blunted flow

Patients will be clinically monitored throughout their hospital stay. Follow-up NIHSS scoring will be conducted at 72 hours. Functional status at discharge will be assessed using the modified Rankin Scale (mRS). The primary aim is to correlate early hemodynamic findings with short-term neurological evolution. Secondary aims include assessing the association of collateral circulation with clinical improvement and determining whether TCD-derived indices can serve as non-invasive prognostic markers.

All diagnostic and therapeutic decisions (e.g., reperfusion therapy, ICU admission) will be made by the attending medical team independently of study procedures. No experimental interventions are included.

The study intends to demonstrate that early bedside neurosonology can provide clinically relevant prognostic information, particularly useful in settings with limited access to advanced imaging modalities like CT perfusion or MRI.

Data will be collected and managed using encrypted case report forms. Statistical analysis will include correlation tests and multivariate regression models to adjust for clinical covariates.

The primary outcome is the correlation between baseline MCA flow velocity and the change in NIHSS score at 72 hours. Secondary outcomes include:

The association between collateral circulation and clinical improvement,

Functional status at hospital discharge, assessed using the modified Rankin Scale (mRS).

The study will take place over 12 months at Clínica México, a secondary-level hospital located in Piedras Negras, Coahuila, Mexico. The study is non-interventional: all treatment decisions, including eligibility for thrombolysis or endovascular therapy, are made by the attending clinical team and are not influenced by study participation.

This investigation is designed to assess the prognostic value of TCD as a non-invasive, bedside tool for early risk stratification in AIS, particularly in settings with limited access to advanced neuroimaging.

Inclusion Criteria:

• Age ≥ 18 years
• Clinical diagnosis of acute ischemic stroke
• Onset of symptoms ≤ 24 hours before admission
• Underwent or will undergo transcranial Doppler ultrasound within 24 hours of symptom onset
• Able to provide informed consent or consent obtained from a legal representative

Exclusion Criteria:

• Evidence of intracerebral hemorrhage on imaging
• Inadequate temporal acoustic window for transcranial Doppler
• Intubated or hemodynamically unstable prior to Doppler evaluation
• Known diagnosis of neurodegenerative disease significantly affecting baseline neurological function (e.g., advanced dementia, Parkinson's disease)
• Refusal to participate or withdrawal of consent

Not decided.