Is the search for right-to-left shunt still worthwhile?

Area of Science:

• Cardiology
• Neurology
• Medical Diagnostics

Background:

• Patent foramen ovale (PFO) is a common congenital heart defect.
• Its association with cryptogenic stroke and other conditions is debated.
• Transcranial color-coded Doppler (TCCD) is effective for diagnosing right-to-left shunts (RLS).

Purpose of the Study:

• To evaluate the prevalence and degree of RLS in patients undergoing TCCD.
• To investigate RLS in conditions potentially linked to paradoxical embolism.
• To identify predictors of RLS and refine diagnostic criteria.

Main Methods:

• Standardized TCCD protocol used for PFO assessment.
• Defined cutoff points (10 or 20 microbubbles) for RLS detection.
• Analysis of RLS prevalence and degree across 10 diagnostic categories and controls.

Main Results:

• Higher RLS prevalence observed in stroke (53.3%), TIA (45.7%), and migraine with aura (39.7%) compared to controls (25.5%).
• RLS degree was significantly higher in stroke and TIA patients.
• Family history, aspirin use (ASA), and male gender were independent predictors of RLS.

Conclusions:

• Genetic and epidemiological factors like male gender are important for assessing PFO-related cerebrovascular risk.
• New TCCD microbubble count thresholds are proposed to distinguish stroke-related RLS from incidental shunts.
• Refined diagnostic criteria can improve risk stratification for patients with PFO.