Morphometric Features of Patent Foramen Ovale as a Risk Factor of Cerebrovascular Accidents: A Systematic Review and Meta-Analysis

INTRODUCTION: It is still disputable whether specific morphometric features of the patent foramen ovale (PFO) may stratify patients by the related probability that a discovered PFO is incidental or stroke related. OBJECTIVE: We aimed to determine whether certain morphometrical characteristics of PFO are associated with an increased risk of cerebrovascular accidents, using a meta-analytical approach. METHODS: We performed a systematic review of electronic databases for studies that compared morphometric parameters of PFO assessed by transesophageal echocardiography (TEE) in subjects with cryptogenic cerebrovascular accidents (Group 1) and control (Group 2). Data were extracted and pooled into a meta-analysis. RESULTS: A total of 895 patients with PFO were reported (Group 1: 493, Group 2: 402). No difference was found in the PFO channel length (Group 1: 10.8 8.6-12.9 mm vs. Group 2: 10.4 9.1-11.7 mm), as well as in PFO height measured at rest (Group 1: 2.4 1.5-3.3 mm vs. Group 2: 1.8 1.4-2.2 mm). The PFO height measured during a Valsalva maneuver was larger in Group 1 (3.5 2.8-4.1 mm) than in Group 2 (1.7 1.2-2.2 mm). Also, the septal excursion distance was found to be larger in Group 1 (6.4 5.1-7.8 mm) than in Group 2 (3.1 1.8-4.4 mm). The risk of cerebrovascular accident was higher in patients with PFO and concomitant septal aneurysm (OR 4.00; 95% CI 2.63-6.09; p < 0.001) and with large right-to-left shunt PFO (OR 3.81; 95% CI 2.21-6.55; p < 0.001), no such relationship was found for the presence of a Eustachian valve or Chiari's network (OR 1.90; 95% CI 0.90-4.05; p = 0.094). CONCLUSIONS: The TEE may help in identifying PFO that are of high risk of cerebrovascular accident. Greater PFO height during a Valsalva maneuver, larger septal excursion distance, concomitant atrial septal aneurysm, and large right-to-left shunt are associated with stroke-related PFOs.