To retrospectively analyze the diagnostic value of transthoracic contrast transthoracic echocardiography (cTTE) and transoesophageal echocardiography (TEE) in patients with clinically suspected patent foramen ovale (PFO).

The data of cTTE and TEE examinations in 1164 patients with suspected PFO-related diseases at the Department of Ultrasound of the First Medical Center of the PLA General Hospital from August 2014 to June 2019 were retrospectively analyzed. TEE, cTTE, and a combination of the two were used to detect PFO.The diagnostic performance of cTTE for right-to-left shunt and shunt flow, and that of TEE for the morphological and structural characteristics of PFO were analyzed.

There were 314 cases of migraine with aura(MA), 219 cases of migraine without aura (MO), 279 cases of cryptogenic cerebral infarction (CCI) and/or transient is chemic attack (TIA), and 352 cases of other diseases. A total of 282 (24.2%) cases of PFO were detected in 1164 patients. The difference in PFO detection rate between the four clinical groups was statistically significant (χ²=17.94, P<0.001), with the highest PFO detection rate observed in patients with MA (98/314, 31.2%). Of the 1164 patients, 764 underwent cTTE and 170 (170/764, 22.3%) PFOs were detected; 816 underwent TEE and 221 (221/816, 27.1%) PFOs were detected; 412 underwent combined cTTE and TEE examinations and 125(125/412, 30.3%) PFOs were detected. Of the 764 patients who underwent cTTE examination, 474 (474/764, 62.0%) had a right-to-left shunt in cTTE. Among the 170 patients with right-to-left shunt, 101(101/170, 59.4%) had a large amount of shunt flow (101/170, 59.4%); among 383 patients with pulmonary circulation-related right-to-left shunt, 185(185/383, 48.3%) had a small amount of shunt flow; among 79 patients with bidirectional shunt, 54(54/79, 68.4%) had a large amount of shunt flow. PFO width could be recorded in all 221 PFO patients detected by TEE, with an average width of (1.61±0.92) mm, and 78 cases of narrow and long PFO, with an average length of about (10.53±3.52) mm. The shunt was detected by TEE in 132 cases, of which 122 had a left-to-right shunt, 1 had a right-to-left shunt, and 9 had a bidirectional shunt. In addition, 14 cases of atrial septal aneurysm, 20 cases of left atrial septal pouch, and 41 cases of valve filaments were observed.

The detection rate of PFO in patients with MA and CCI and/or TIA is significantly higher than that in patients with MO and other diseases. The combination of TEE and cTTE can improve the detection rate of PFO. The detection of right-to-left shunt and its origin mainly relies on cTTE. Most of the PFO-related right-to-left shunt in PFO-related diseases are medium-large. More than half of patients with PFO-related diseases have a pulmonary circulation-related right-to-left shunt, which highlights the importance of differential diagnosis between the two forms of shunt.