A score of non-contrast transthoracic echocardiography to screen patent foramen ovale in patients with embolic stroke of undetermined source

BACKGROUND: The aim of this study was to develop a screening score system of non-contrast transthoracic echocardiography (TTE) for patent foramen ovale (PFO) in patients with embolic stroke of undetermined source (ESUS). METHODS: We performed a retrospective analysis of 218 consecutive patients with a recent ESUS from 2015 to 2018, who received TTE and transcranial Doppler (TCD) as routine examinations. PFO was diagnosed by the bubble test of TCD. Significant differences of the non-contrast TTE findings and patient characteristics between PFO group and non-PFO group were selected into a score. RESULTS: PFO was diagnosed in 35.8% (78/218) of the patients. Compared with non-PFO group, a larger median aortic root diameter (ARd) (34 mm vs. 32 mm, p = 0.005), a lower median peak E wave velocity (Em) (61.5 cm/s vs. 68 cm/s, p = 0.005) and a lower incidence rate of mitral regurgitation (34.6% vs. 50.7%, p = 0.022) were seen in PFO group. ARd>33 mm and Em < 72 cm/s were the best thresholds to predict PFO in ROC analysis. A four-point score system (MEAD) including TTE criteria (including ARd>33 mm, Em < 72 cm/s and without mitral regurgitation) and no history of diabetes predicted PFO with an area under curve of 0.67 (95%CI 0.57–0.72, p < 0.001). MEAD score ≥ 3 was the best threshold to predict PFO with an accuracy of 0.64 (95% CI 0.57–0.7), a sensitivity of 0.65 (95% CI 0.53–0.75) and a specificity of 0.63 (95% CI 0.55–0.71). CONCLUSION: The MEAD score measured with non-contrast TTE can be used to select patients for bubble test of TCD to increase the diagnostic yield of PFO after ESUS. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12883-022-02565-w.