Shunt volume dynamics in stroke patients with patent foramen ovale

A variation in right atrial and pulmonary arterial pressure might result in a shunt dynamic across a patent foramen ovale (PFO). In the present study we tested if peak exercise facilitates a restoration of right to left shunt (RLS) in stroke patients who demonstrated a functional PFO closure (no evidence of RLS across an initially demonstrated PFO). In stroke patients with PFO demonstrating a functional closure, the RLS was reassessed on peak exercise using contrast-enhanced transcranial Doppler sonography. The exercise procedure consisted of a cardiopulmonary exercise test with supplementary stress echocardiography for assessment of pulmonary circulation. Four stroke patients with initially PFO curtain pattern and a subsequent functional PFO closure (no evidence for RLS) underwent the procedure. In all four patients a RLS could be resurrected during peak physical exercise after a Valsalva strain. While in two patients peak exercise led to an RLS in a countable range of microembolic signals, in two patients a curtain pattern was obtained. One patient showed evidence for reoccurrence of RLS on peak exercise without a Valsalva strain. The patients with curtain pattern had a better peak exercise performance. Although the systolic pulmonary arterial pressure increased during exercise in all patients, there was no direct correlation with the detected RLS. After a functional PFO closure peak exercise combined with a Valsalva strain facilitates the reoccurrence of RLS in stroke patients.