Assessment of Morphology of Patent Foramen Ovale Associated with Cryptogenic Stroke

Background: Patent foramen ovale (PFO) is the correlation with migraine headaches, cryptogenic stroke. The transcatheter closure of PFO has been proven effective preventing cryptogenic stroke (CS), it is necessary to determine the structure of PFO associated with CS. This study aimed to detect the morphological and function of PFO by using transesophageal echocardiography (TEE) and contrast transthoracic echocardiography (c-TTE) to assess the morphology of PFO associated with CS, and seek out the high-risk factors of PFO for CS. Methods: 113 test patients who suffered CS combining with PFO and 117 control patients diagnosed PFO without stroke were enrolled. The structure of PFO were detected by TEE and c-TTE. The following parameters were measured by TEE: the length and height of the PFO tunnel during Valsalva, the presence of atrial septal aneurysm (ASA), the angle between inferior vena cava (IVC) and PFO, and thickness of septum secundum, and the severity of right-to-left (RLS) was tested by c-TTE. The differences structure of PFO between the test patients and controls were compared, and the correlation between the PFO parameters and CS in test group was analyzed. Based on logistic analyses, we sought out the high-risk factor of PFO for CS. Results: The patients of test group were older than that of control group (56 [48-67.5] years vs 42 [31-51] years, P < 0.001). The height of the PFO during Valsalva (2.5[2-3] mm vs 2.1[1.6-2.8] mm, P = 0.022) were found to be greater in test group than those in control group. The length of the PFO during Valsalva (13.03 ± 4.18 mm vs 11.35 ± 3.84, P = 0.002) were found to be greater in test group than those in control group. The low-angle PFO( the angle between IVC and PFO ≤ 10°) was more common in patients with CS than those in control (48 (42.5%) vs 13 (11.1%)， P ＜0.001). Besides, the occurrence rate of ASA in test group is more frequently compared with control group (20 (18%) vs 9(8%), P =0.022). RLS III during Valsalva in test group (85 (75.2%)) was significantly higher than that in control group (70 (59.8%)). RLS II during Valsalva in the without CS group (36 (30.8%)) was significantly higher than that in the CS group (18 (15.9%)). There was no difference between the two groups for RLS I during Valsalva and all grades of RLS at rest. There was no significant difference regarding the thickness of septum secundum as well. Multivariate analysis showed that the length of the PFO during Valsalva, the presence of ASA, RLS III during Valsalva, and the low-angle PFO were independently relevant factors for CS. Conclusions: The relation between PFO and CS is multifactorial. The length of the PFO tunnel, the low-angle PFO, RLS III during Valsalva and the presence of ASA were the greater risk for CS, The TEE combined with c-TEE may help in identifying PFO that is of high risk for CS and screening out the patients for transcatheter closure of PFO.