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| Study of patent foramen ovale and its shunt direction by transthoracic echocardiography in children |
| LIN Teng1, ZHANG Zhi-min2, GUO Liang1 |
| 1. Department of Ultrasound, the First Affiliated Hospital of Shantou University Medical College, Shantou Guangdong 515041, China; 2. Department of Ultrasound, Minsheng Hospital of Chaonan of Shantou, Shantou Guangdong 515144, China |
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Abstract Objective: Using transthoracic echocardiography(TTE) to investigate the prevalence, characteristic and shunt direction of patent foramen ovale(PFO). Methods: A total of 426 children were divided into infant group(0～3 year, 243 cases) and child group(4～7 year, 183 cases), then divided into infant associated with congenital heart disease(CHD) group(group A, 93 cases), normal infant group(group B, 150 cases), child with CHD group(group C, 60 cases) and normal child group(group D, 123 cases) according to whether complicating CHD. The characteristic and shunt direction of PFO was observed by TTE. Right-sided contrast echocardiography were performed if necessary. Results: Eighty-six cases were detected to have PFO in all the 426 children. TTE showed echo separating between foramen ovale valve and deuto-atrial septum from 1.5mm to 5.7mm and small oblique shunt at atrium level. Forward direction, low speed and continuous shunt in Doppler frequency was showed in most PFO cases. The size of PFO between infant group and child group without significant difference[(2.9±0.7)mm vs (2.6±1.0)mm, P>0.05]. The left to right shunt in 73 PFO cases, right to left shunt in 7 PFO cases, bidirectional shunt in 4 PFO cases and potential shunt in 2 PFO cases were diagnosed. Patients with right to left shunt or bidirectional shunt were those complicating with certain CHD or pulmonary artery hypertension. The detection rate of PFO in infant group and child group was 26.7% and 11.5% respectively. Simultaneously the detection rate of PFO in group A, group B, group C and group D was 33.3%, 22.7%, 18.3%, 8.1% respectively. Compared the detection rate of PFO in each groups: infant group exceed child group, group A exceed group C, group B exceed group D and group C exceed group D(P<0.01 or P<0.05). Conclusion: The detection rate of PFO in infancy is higher than childhood obviously, some kinds of CHD may delay the closure of PFO. Children with PFO often showed left to right shunt in conditions without certain CHD and pulmonary hypertension. TTE has high value in the diagnosis of PFO in children, contrast echocardiography can help to identify latent shunt of PFO.
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Received: 17 December 2008
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2009, Vol. 20 
