Right atrium and cryptogenic ischaemic stroke in the young: a case-control study

Area of Science:

• Cardiology
• Neurology
• Medical Imaging

Background:

• Cryptogenic stroke affects young adults, with patent foramen ovale (PFO) being a potential cause.
• Left atrial (LA) dysfunction is implicated, but right atrial (RA) and right atrial appendage (RAA) dynamics are less understood.
• This study investigates bi-atrial dysfunction and blood stagnation as contributors to thrombosis in cryptogenic stroke patients with PFO.

Purpose of the Study:

• To evaluate right atrial (RA), right atrial appendage (RAA), and left atrial (LA) dynamics in young cryptogenic stroke patients.
• To identify associations between atrial dysfunction, right-to-left shunt (RLS), and stroke etiology.
• To explore potential mechanisms of thrombosis in PFO-associated cryptogenic stroke.

Main Methods:

• Cardiac magnetic resonance (CMR) imaging was used in 30 cryptogenic stroke patients (18-49 years) and 30 controls.
• Developed a novel method to estimate RAA volume using anatomical landmarks.
• Calculated atrial expansion indices and pulmonary to systemic blood flow ratio (Qp/Qs); RLS assessed via echocardiography/Doppler.

Main Results:

• RA and RAA volumes were similar, but RAA and LA expansion indices were significantly lower in patients versus controls (p<0.05).
• A higher prevalence of moderate-to-severe right-to-left shunt (RLS) was observed in patients (24%) compared to controls (3%) (p=0.012).
• RLS was associated with reduced expansion indices in all atria and appendages and a lower Qp/Qs ratio.

Conclusions:

• Young adults with cryptogenic stroke exhibit bi-atrial dysfunction, characterized by impaired atrial appendage function.
• This dysfunction is associated with moderate-to-severe right-to-left shunts (RLS).
• Bi-atrial dysfunction and RLS represent potential mechanisms contributing to PFO-related cryptogenic stroke.