Le Moigne E, Timsit S, Ben Salem D, Didier R, Jobic Y, Paleiron N, Le Mao R, Joseph T, Hoffmann C, Dion A, Rousset J, Le Gal G, Lacut K, Leroyer C, Mottier D, Couturaud F. Patent Foramen Ovale and Ischemic Stroke in Patients With Pulmonary Embolism A Prospective Cohort Study.
Is has been previously shown that patients with acute pulmonary embolism (PE) face an increased risk of ischemic stroke, especially in the first days after the PE diagnosis. This risk has been suggested to be related to patent foramen ovale (PFO). In this paper of the month, French researchers report the results of their prospective study on the frequency and pathophysiology of ischemic stroke in patients with PE and stroke. A total of 361 consecutive patients with symptomatic acute PE were subjected to contrast transthoracic or transesophageal echocardiography, and cerebral magnetic resonance imaging within 7 days of enrolment and within 10 days after PE diagnosis. Only patients with onset of symptoms less than 5 days before diagnosis were included. The primary outcome was a diagnosis of ischemic stroke based on clinical results and/or imaging. Among the 324 patients with a conclusive result echocardiography, PFO was detected in 43 patients (13%). Silent or symptomatic recent ischemic stroke was diagnosed in 24 of 315 patients (7.6%) with conclusive echocardiography and available MRI scan. Stroke occurred more frequently in those patients with PFO (21% vs 5.5%; relative risk 3.9, 95%CI 1.6 to 8.7). One third of the strokes was symptomatic. Based on these findings, the authors concluded that paradoxical embolism is likely an important mechanism of ischemic stroke in patients with concomitant PFO and PE. Interestingly, the prevalence of right ventricular overload was not different between patients with and without PFO. The main limitations of this study was the lower than expected rate of PFO, which lead to a change in sample size calculation during the study.
What does this study teach us?
Its results do not support routine screening for PFO in all patients with PE. Even so, knowledge of a PFO may influence the decision of duration of anticoagulant therapy. Moreover, (silent) stroke which was prevalent in the study population, could be a relevant determinant of post-PE syndrome and long-term functional limitations after acute PE.