Patent foramen ovale and stroke in intermediate-risk pulmonary embolism

Patent foramen ovale (PFO) in pulmonary embolism (PE) is associated with an increased risk of complications. However, little is known about PFO and ischemic stroke prevalence, particularly in acute intermediate-risk PE. In addition, in this context, the so-called "gold standard" method of PFO diagnosis remains unknown. We aimed to evaluate PFO and ischemic stroke prevalence and determine which of transesophageal echocardiography (TEE) or transthoracic echocardiography (TTE) is the best PFO diagnostic method in this context.

We conducted a prospective monocentric study of consecutive patients with intermediate-risk PE in whom a TEE and TTE with contrast were performed. Brain MRI was used to confirm clinically obvious strokes or to diagnose subclinical ones.

Forty-one patients with intermediate-risk PE were identified over a 9-month period. Contrast TEE revealed PFO in 56.1%, whereas contrast TTE showed PFO in only 19.5% (P < .001). Of note, all PFOs observed with TTE were also diagnosed by TEE. Ischemic stroke occurred in 17.1% and was always associated with PFO and large shunt.

PFO and related ischemic strokes are frequent in intermediate-risk PE. TEE is much more efficient than TTE for PFO diagnosis. Considering the high risk of intracranial bleeding with thrombolysis in PE, which may be partly due to hemorrhagic transformation of subclinical strokes, screening PFO with TEE should be considered in intermediate-risk PE when thrombolytic treatment is discussed.