A comparison of methods to determine patent foramen ovale size

Abstract

Background: Patent foramen ovale (PFO) is implicated in the pathogenesis of clinical conditions such as cryptogenic stroke and migraine with aura. This study evaluated the challenges of sizing a PFO with different contemporary imaging modalities and assessed the relationship between PFO size and severity of the right-to-left shunt (RLS). Methods: Patients who were referred to interventional cardiology with the diagnosis of a PFO and had undergone intra-procedural balloon sizing (n = 147), transesophageal echocardiogram (TEE) imaging (n = 67), or intracardiac echocardiogram (ICE) imaging (n = 73) at the time of workup were included in this study. TEE and ICE were used to obtain PFO length and height during normal respiration. A sizing balloon was used to obtain PFO width and height after the septum primum was opened with balloon inflation. Results: The mean PFO length measured by TEE and ICE differed significantly (n = 27, 13.0 ± 4.1 vs. 9.9 ± 3.2 mm, p = .001). The mean PFO height measured by TEE and ICE (n = 27, 1.4 ± 0.6 vs. 1.7 ± 0.6 mm, p = .04), TEE and sizing balloon (n = 56, 1.5 ± 1.2 vs. 10.5 ± 4.2 mm, p < .0001), and ICE and sizing balloon (n = 66, 1.7 ± 0.7 vs. 9.1 ± 3.7 mm, p < .0001) also differed significantly. A poor correlation existed between anatomic PFO length or height and functional Spencer TCD grade RLS flow with Valsalva, irrespective of the imaging modality used. Conclusions: The determination of a PFO size is dependent on the imaging modality used. Sizing balloon demonstrates a larger width or height than ultrasound imaging methods, such as TEE and ICE, because a PFO remains closed most of the time, leading the echocardiogram to underestimate the potential PFO size. Additionally, PFO length and height correlate poorly with the functional RLS grade. These findings imply that ultrasound-based size characterization should not be used to determine whether a PFO should be closed.

Three-dimensional Transesophageal Echocardiography for Transcatheter Patent Foramen Ovale Closure: Standardizing Anatomic Nomenclature and Novel Sizing Concepts

“… 8 , 9 , 10 We recommend that the term PFO tunnel “height” be used to describe the separation between the septum primum and septum secundum (i.e., the minor axis of the oval opening), although both “width” and “height” have been used interchangeably in the literature to describe this dimension. 1 , 7 , 12 , 13 We reserve the use of the term PFO tunnel “width” to describe the size of the RA or LA openings, which are only appreciated with en face PFO visualization (i.e., the major axis of the oval opening). The PFO tunnel width has only recently been emphasized in the literature 11 and is better suited to be measured with biplane or 3D multiplanar imaging rather than 2D imaging alone.…”

“…However, PFO device sizing is currently highly variable, with multiple methods being utilized in clinical practice. 1 Nomenclature for describing PFO size remains unstandardized and continues to be based primarily on two-dimensional (2D) imaging despite our improved understanding of PFO morphology from three-dimensional (3D) transesophageal echocardiography (TEE; 3D-TEE). 2 , 3 Furthermore, residual right-to-left shunting remains as high as 25% and is associated with a 3-fold higher risk of recurrent stroke or transient ischemic attack after transcatheter PFO closure.…”

Intelligent Prediction of Cryptogenic Stroke Using Patent Foramen Ovale from TEE Imaging Data and Machine Learning Methods

“…Other studies have determined that PFO size is closely related to CS. Nevertheless, some studies have shown that there is no significant association between the anatomy of PFO and paradoxical cerebral embolism [33]. Schuchlenz et al [34] concluded that PFO size measured at exit location (left atrial side) is an independent risk factor for ischemic events, and that patients with a PFO size > 4 mm have a substantial risk of recurrent strokes.…”

The Efficacy of Contrast Transthoracic Echocardiography and Contrast Transcranial Doppler for the Detection of Patent Foramen Ovale Related to Cryptogenic Stroke

“…In contrast, cTTE and cTCD have the advantage of being noninvasive and having a lower cost. Although the methods have been used in many hospitals, the results of tests vary considerably [11][12][13]. Some studies have found that microbubbles appearing in the left chambers in 3 or 5 cardiac cycles after full right atrial opacification during cTTE were related to PFO [16,22,23].…”

“…CTEE has become the main means of PFO detection, but it has the disadvantage of being semi-invasive and dose not exempt from risks. As noninvasive methods, cTTE and cTCD are used as screening tests for PFO, but the reliability for PFO diagnosis is controversial [11][12][13]. This study is aimed at investigating the efficacy of cTTE and cTCD versus cTEE to detect PFO, exploring a more cost-effective and reliable method for the diagnosis of PFO related to cryptogenic stroke.…”