[Analysis of contrast echocardiography for detecting right to left shunt in adults with patent foramen ovale].

Objective: To analyze the contrast echocardiography for detecting right to left shunt in adults with patent foramen ovale(PFO), and study the relationship between PFO and cryptogenic stroke. Methods: Clinical data of forty-six adults patients with PFO diagnosed by transesophageal echocardiography(TEE)from March, 2012 to March, 2017 were retrospectively collected, and the patients were divided to 3 groups according to the direction and brightness of the color Doppler shunts: obvious left-to-right shunt (OLRS, group A), weak left-to-right shunt(WLRS, group B), bi-directional shunt(BDS, group C). A right-to-left shunt (RLS) scale was calculated using the method of 10 ml hand-operated saline for contrast echocardiography. Results: There were seventeen cases in group A, four cases (23.5%) showed RLS at level 1, and thirteen cases (76.5%) showed no RLS; there were twenty cases in group B, and all cases (100%) showed RLS, with five cases (25%) at level 1 and fifteen cases (75%) at level 2-3; there were nine cases in group C, and all cases (100%) showed RLS, with two cases (22.2%) at level 1 and seven cases (77.8%) at level 2-3. Anteroposterior diameter of left atrium of patients with no RLS (4.8 cm±0.6 cm) was significantly larger than that of patients with RLS in contrast echocardiography (3.6 cm±0.5 cm)(P=0.000). Conclusions: OLRS of adults with patent foramen ovale and with larger left atrium have less RLS than WLRS and DLRS with normal left atrium in contrast echocardiography.The possibility of paradoxical embolism in WLRS and DLRS is higher than that in OLRS, which should be taken seriously in clinical practice.