Prevalence of patent foramen ovale and stroke in pulmonary embolism patients

Purpose: Patent foramen ovale (PFO) is associated with paradoxical embolism and mortality in pulmonary embolism (PE). The aim of this study was to assess the prevalence of PFO comparing trans-thoracic echocardiography (TTE) and trans-oesophageal echocardiography (TOE) and its association with ischaemic stroke (as assessed by magnetic resonance imaging (MRI)) in patients hospitalized for PE. Methods and results: We prospectively enrolled 40 consecutive patients hospitalized in the cardiology department for intermediate early-mortality risk PE. Patients with recent history of stroke or contra-indication to TOE were excluded from this study. Local ethics approval was obtained for the study. Contrast TTE and TOE were performed within 5 days after admission. Mean time from admission to TOE was 3.4±1.2 days, whereas mean time to MRI was 14±5.8 days. On admission, mean systolic arterial pressure was 132±40 mmHg, mean troponine Ic was 0.4±1.7 ng/ml (normal reference value < 0.06 ng/ml) and mean BNP was 585±2200 pg/ml. PFO was found in 22.5% (n=9) and 52.5% (n=21) of our patients, respectively with TTE and TOE. Compared with TTE, TOE significantly improved the sensitivity of echocardiography in detecting PFO (p = 0.002). No significant difference on admission's characteristics was found between patients without PFO (PFO-; n=19) and patients with PFO (PFO+; n=21). On MRI evidence of recent ischaemic stroke was found in 7 PFO+ patients (33.3%), versus none in PFO- patients (p=0.004). In the sub-group of stroke patients (n=7), TOE was positive for PFO in all, whereas TTE failed to identify PFO in 3 of them (recognition of PFO, TOE vs TTE: 100 vs 57%, p=0.02). No complication of TOE occurred in our cohort (including GI-bleeding). Conclusion: PFO is frequent in patients hospitalized for intermediate risk-PE, and occurred in 52.5% of our patients. In our study, PFO is strongly associated with ischaemic stroke on MRI and recognition of PFO in patients with PE could help identifying patients with high-risk of stroke and potential bleeding complications.