An observational study in Patent Foramen Ovale, Cryptogenic Stroke and Transient Ischemic Attack Due to Embolism, sponsored by Yonsei University. Recruiting at 1 site in South Korea. Open to participants aged 19 Years and older. Per ClinicalTrials.gov, last updated 2026-07-23.
Sponsored by Yonsei University · Observational
Patent foramen ovale (PFO) is a congenital interatrial communication present in about one quarter of the general population and is recognized as a major cause of cryptogenic stroke. Percutaneous PFO closure reduces recurrent stroke, but a residual right-to-left shunt persists in 20 to 40 percent of patients after device implantation. Long-term data on device performance, the evolution of residual shunt over time, new-onset atrial fibrillation and other prognostic factors remain limited.
This single-center registry evaluates the long-term efficacy and safety of percutaneous PFO closure and identifies the clinical, anatomical, procedural and pharmacological factors associated with clinical and echocardiographic outcomes. The registry combines a retrospective cohort of patients treated at Severance Hospital between 2010 and March 2026 with a prospective registry extension that enrolls patients undergoing PFO closure after institutional review board approval, with follow-up for up to 119 months.
Clinical outcomes include recurrent ischemic stroke or transient ischemic attack, all-cause death, device-related complications and new-onset atrial fibrillation. Echocardiographic outcomes are assessed by serial agitated saline transthoracic echocardiography, which allows the presence, grade and longitudinal trajectory of residual shunt to be characterized.
Design: ambispective observational registry conducted at Severance Cardiovascular Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
Part A (retrospective cohort): consecutive patients aged 19 years or older who underwent percutaneous PFO closure between 2010 and March 2026 and had at least one post-procedural agitated saline transthoracic echocardiography. Data are collected by direct review of electronic medical records, with the data cut-off set at the date of institutional review board approval. The requirement for informed consent is waived for this part.
The retrospective component comprises approximately 140 patients who underwent closure between 2010 and March 2026. A subgroup of these patients underwent two or more serial agitated saline transthoracic echocardiography examinations and is analyzed for the longitudinal trajectory of residual shunt.
Part B (prospective registry extension): patients aged 19 years or older who undergo percutaneous PFO closure after institutional review board approval and provide written informed consent. Follow-up visits are scheduled at 6, 12, 24, 48, 72, 96 and 119 months. Agitated saline transthoracic echocardiography is performed 6 months after closure and repeated at subsequent follow-up visits as clinically indicated.
Data collected: demographics and body mass index, smoking status, comorbidities (hypertension, diabetes mellitus, dyslipidemia, atrial fibrillation, coronary artery disease, deep vein thrombosis, pulmonary embolism, hypercoagulable state), index event characteristics (stroke or transient ischemic attack type, TOAST classification, brain imaging, Risk of Paradoxical Embolism score), echocardiographic and anatomical variables (atrial septal aneurysm and excursion distance, septal hypermobility, PFO tunnel length, PFO opening size, Eustachian valve, Chiari network, left ventricular ejection fraction), procedural variables (device type and size, guidance modality, balloon sizing, procedure time, fluoroscopy time, procedural complications), antithrombotic therapy, serial agitated saline transthoracic echocardiography results, clinical events and modified Rankin Scale.
Agitated saline transthoracic echocardiography: 9 mL of normal saline mixed with 1 mL of air is agitated between two syringes and injected through an antecubital vein at rest and during the Valsalva maneuver. A study is positive when microbubbles appear in the left heart within three cardiac cycles after right atrial opacification. Shunt grade is assigned from the maximum number of microbubbles in the left heart within three cardiac cycles: small (1 to 10), moderate (11 to 30) or large (more than 30), in accordance with American Society of Echocardiography guidance. In patients with two or more serial examinations, the sequence of positive and negative results over time is recorded and the longitudinal pattern of residual shunt is classified.
Statistical analysis: continuous variables are summarized as mean with standard deviation or median with interquartile range, and categorical variables as frequency and percentage. Cumulative event rates are estimated by the Kaplan-Meier method and compared with the log-rank test. Cox proportional hazards models are used to estimate hazard ratios with 95 percent confidence intervals. Predictors of residual shunt are examined by logistic regression. Analyses are performed with R version 4.0 or later, and a two-sided p value below 0.05 is considered statistically significant.
136 studies on the registry are indexed under Foramen Ovale, Patent; 47 are open to participants now.
This study's planned enrollment of 400 is above the median of 254 across 59 observational studies indexed under Foramen Ovale, Patent.
Browse Foramen Ovale, Patent studies →Yonsei University is the lead sponsor of 1,418 studies on the registry; 241 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Consecutive adults who underwent percutaneous patent foramen ovale closure at a single tertiary referral center in Seoul, Republic of Korea. The retrospective cohort comprises patients treated between 2010 and March 2026 who had at least one post-procedural agitated saline transthoracic echocardiography. The prospective cohort comprises patients undergoing closure after institutional review board approval who provide written informed consent. The population reflects routine clinical practice, and treatment is not assigned by protocol.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Patients aged 19 years or older who underwent percutaneous patent foramen ovale closure between 2010 and March 2026 and had at least one post-procedural agitated saline transthoracic echocardiography. Approximately 140 patients. Data are obtained by review of electronic medical records under a waiver of informed consent.
Group/Cohort Description: Patients aged 19 years or older who undergo percutaneous patent foramen ovale closure after institutional review board approval, provide written informed consent, and are followed prospectively for up to 119 months.
Number of participants with recurrent ischemic stroke or transient ischemic attack
First recurrent ischemic stroke or transient ischemic attack after closure, identified from medical records and classified by event type and TOAST criteria. Reported as the number of participants with an event and as the event rate per 100 patient-years.
Time frame: From patent foramen ovale closure to the last clinical follow-up: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Number of participants with residual right-to-left shunt on agitated saline transthoracic echocardiography, by shunt grade
Residual right-to-left shunt is defined as the appearance of microbubbles in the left heart within three cardiac cycles after right atrial opacification. Shunt grade is assigned from the maximum microbubble count: small (1 to 10), moderate (11 to 30) or large (more than 30). Reported as the number of participants in each grade.
Time frame: From patent foramen ovale closure to the last follow-up echocardiography: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Number of participants who die from any cause
Death from any cause, ascertained from medical records.
Time frame: From patent foramen ovale closure to the last follow-up: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Number of participants with device-related complications
Device embolization, device thrombus, erosion, reintervention or surgical device removal.
Time frame: From patent foramen ovale closure to the last follow-up: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Number of participants with new-onset atrial fibrillation
Atrial fibrillation newly documented on electrocardiography, Holter monitoring or event recorder, classified as paroxysmal, persistent or permanent.
Time frame: From patent foramen ovale closure to the last follow-up: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Number of participants with the composite of recurrent ischemic stroke or transient ischemic attack, all-cause death, or device-related complications
Composite of recurrent ischemic stroke or transient ischemic attack, all-cause death, and device-related complications, analyzed as time to first event.
Time frame: From patent foramen ovale closure to the last follow-up: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Longitudinal pattern of residual shunt on serial agitated saline transthoracic echocardiography
Among participants with two or more serial agitated saline transthoracic echocardiography studies, the sequence of positive and negative results over time is recorded and the longitudinal pattern of residual shunt is classified.
Time frame: From patent foramen ovale closure to the last follow-up: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Time to spontaneous resolution of residual shunt
Interval from the first positive to the first negative agitated saline transthoracic echocardiography, estimated by the Kaplan-Meier method.
Time frame: From patent foramen ovale closure to the last follow-up: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Predictors of residual right-to-left shunt on agitated saline transthoracic echocardiography
Measure: adjusted odds ratio with 95% confidence interval for the presence of residual right-to-left shunt, defined as microbubbles in the left heart within three cardiac cycles after right atrial opacification on agitated saline transthoracic echocardiography. Measurement tool: multivariable logistic regression model. Unit of measure: odds ratio. Candidate variables entered into the model include device type, device size, right atrial disc diameter, patent foramen ovale tunnel length, patent foramen ovale opening size, atrial septal aneurysm, septal hypermobility, imaging guidance modality (transesophageal or intracardiac echocardiography) and use of balloon sizing.
Time frame: From patent foramen ovale closure to the last follow-up: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Functional status measured with the modified Rankin Scale
Modified Rankin Scale score at follow-up, ranging from 0 (no symptoms) to 6 (death); higher scores indicate greater disability.
Time frame: From patent foramen ovale closure to the last follow-up: up to 16 years in the retrospective cohort and up to 119 months in the prospective cohort
Plan to share: No — Individual participant data are not planned to be shared.
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