Clinical Research Directory

Pulmonary Embolism and Right-to-Left Shunts

Every fetus has a small hole in their heart, called a foramen ovale when they are developing in the womb. For most people this hole closes shortly after birth, but it doesn't close completely in 1 out of every 4 people. This is called a "patent" foramen ovale, or PFO. In people with a PFO it is possible for a blood clot in a vein to enter the heart, pass through the opening, and then go into an artery - this is referred to as a paradoxical embolism which passes through a "Right-to-Left Shunt," or RLS. If this occurs, the blood clot can cause a stroke. The most common RLS (more than 90%) is a PFO. Much rarer causes include other types of holes in the heart (like an atrial septal defect, or ASD), or a vascular communication in the lungs (like a pulmonary arteriovenous malformation, or AVM). We are investigating whether people with a PE are at higher risk of stroke if they happen to have an RLS compared to PE patients who don't have an RLS. This study will simply observe and compare the differences in stroke-related outcomes between those 2 groups. Participation in the study last roughly 90-days and includes the following activities: * The study team will review your medical records to collect general information such as your age, sex, race/ethnicity, height, weight, medications, medical history, and other medical information * Magnetic Resonance Imaging (MRI) of your brain will be done as soon as possible following your enrollment in the study. For more information on MRI scans, please see the "MRI scan" section below. * A Transcranial Doppler (TCD) with bubble study will be performed to determine if an opening is present in your heart or lungs. TCD is performed using ultrasound. A contrast called agitated saline will be injected into your vein for this test. * You will be asked to return for a follow-up visit 90 days after your pulmonary embolism. At this visit, the following will occur: 1. A second MRI of your brain will be performed. 2. You will complete a questionnaire to evaluate whether you may have had a stroke since being discharged from the hospital 3. You will meet with a member of the study team who will collect information about your health status.

SENIOR: Stroke Prevention in the Elderly by Patent Foramen Ovale closuRe vs Anticoagulation

Patent foramen ovale (PFO) is an important mechanism of embolic stroke of undetermined source (ESUS). Current guidelines recommend PFO closure for high-risk PFO in patients younger than 60 years, and a recent retrospective cohort study from Taichung Veterans General Hospital has shown that closure is effective and safe in older adults; however, the optimal treatment strategy for those \>60 years and direct head-to-head comparisons of PFO closure versus direct oral anticoagulants (DOACs) remain insufficient. Robust evidence from a multicenter study combining prospective and retrospective cohorts is warranted. The SENIOR study is a multicenter observational cohort registry with a combined retrospective and prospective design. The prospective period is from September 15, 2025 to December 31, 2031, and the retrospective period covers January 1, 2013 to September 1, 2025; target sample sizes are 400 (prospective) and 500 (retrospective). We will enroll adults with ESUS and PFO; the prospective arm will focus on patients aged \>60 years with PFO related stroke. Treatments will be assigned as PFO closure, standard-dose DOAC, or antiplatelet agents (if DOAC intolerance) by local principal investigator. The primary outcome is recurrent ischemic stroke or transient ischemic attack. Secondary outcomes include 6-month functional outcome, all stroke, and serial comparison of atrial cardiopathy changes. Safety endpoints include peri-procedural adverse events (including newly-onset atrial fibrillation), hemorrhagic stroke, and all caused mortality. Clinical presentation, imaging, cardiac testing, biomarker, and genetic data will be collected for stratified and multivariable analyses.

Non-Invasive Detection of Right-to-Left Cardiac Shunts

This study will test the sensitivity of a novel, battery-powered, non-invasive ultrasound device to detect a right-to-left shunt

Cerebral Microembolization Associated With PFO Closure

This study aims to investigate (1) the de novo cerebral microembolization in patients who undergo transcatheter closure of PFO or ASD, and (2) evaluate the relationship between de novo cerebral microembolization and in situ thrombus within PFO.