Grading Right-to-Left Shunt With Transforaminal Doppler: A Valid Approach in Patients With Cryptogenic Stroke

Area of Science:

• Neurology
• Cardiology
• Medical Imaging

Background:

• Right-to-left shunt (RLS), often due to patent foramen ovale (PFO), is a key cause of cryptogenic stroke (CS) in young adults.
• Transcranial Doppler (TCD) with agitated saline is sensitive for RLS detection via transtemporal (TTD) approach.
• Some patients have inadequate temporal bone windows for TTD.

Purpose of the Study:

• To assess the accuracy of transforaminal TCD (TFD) for diagnosing RLS.
• To compare TFD with transtemporal TCD (TTD) and transesophageal echocardiogram (TEE).

Main Methods:

• Patients with CS or TIA underwent RLS testing using TFD and TTD protocols.
• Concordance of RLS grading between TFD and TEE was evaluated using weighted kappa.
• TTD and TFD approaches were directly compared.

Main Results:

• Forty patients were analyzed; 70% had medium/large RLS on TTD, 67.5% on TFD.
• TEE confirmed medium/large PFO in 82.6% of cases.
• High agreement was found between TFD and TEE for RLS grading (kappa=0.684) and between TTD and TFD (kappa=0.73).

Conclusions:

• Transforaminal TCD (TFD) is a validated method for RLS diagnosis.
• TFD demonstrates substantial agreement with TEE in grading RLS.
• TCD, including TFD, can identify patients with significant RLS who are candidates for PFO closure.