Quantification of Patent Foramen Ovale Shunt Severity by TEE and TCD in Routine Clinical Practice

Background: The presence of a large physiologic shunt, defined as >20 left atrial microbubbles within 3 cardiac cycles on transesophageal echocardiography(TEE), is a randomized controlled trial-validated indication for patent foramen ovale(PFO) closure in patients with cryptogenic ischemic stroke. The frequency with which this information is available from clinical TEE reports has not been well delineated. Methods: Among consecutive ischemic stroke patients admitted to an academic medical center undergoing TEE between 2022-2023, TEE reports were reviewed to determine frequency with which formal clinical-trial definition-adherent characterization of PFO shunt size was provided, the frequency of informal PFO shunt size descriptions, and correlations with transcranial Doppler(TCD) formal shunt grades (Spencer). Results: Among 77 patients, the median age was 64(IQR 56-73), and 33(43%) were female. On TEE, shunt presence was assessed by bubble study in 60(78%), direct Doppler alone in 5(7%), and neither in 12(16%). Among patients with bubble study, a right-to-left shunt(RLS) potentially due to PFO was present 25(42%). RLS severity was quantified on the clinical report in 16%(4/25) of PFO patients, all with small (<20) shunts. For the remaining 21(84%), reports informally characterized shunt severity with various descriptive terms, including "small/mild/trace"(13 cases), "moderate/medium"(6), and "large"(1). TCD bubble studies were performed in 76%(19/25) of the TEE RLS PFO patients. Shunt severity correlation between TEE and TCD was 100%(3/3) for the formally quantified TEE shunts, un-assessable in one patient with non-specific shunt size characterization on TEE, and poor(3/15, 20%) for the remaining 15 informally assessed TEE shunts, with 47%(7/15) of shunts categorized as larger on TCD and 33%(5/15) smaller on TCD than TEE. Conclusions: Quantified, evidence-based ratings of PFO shunt severity were present in less than 1 of every 6 TEE reports, and informal size estimates correlated poorly with TCD quantification of shunt severity. Patient management would be aided by inclusion of formal PFO shunt size quantification in all clinical stroke patient TEE reports. ### Competing Interest Statement P.Y.Sun: None.J.M.Tobis: n/a. D.S.Liebeskind: Consultant; ; Cerenovus, Genentech, Medtronic, Stryker, Rapid Medical. R.C.Alfonso: None. J.L.Saver: Consultant; ; Medtronic, Abbott, Roche, BrainsGate, BrainQ, Bayer, CSL Behring, Rapid Medical, Novo Nordisk, Individual Stocks/Stock Options; ; QuantalX. There are no unlabeled/unapproved uses of drugs or products. ### Funding Statement None ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the University of California Los Angeles Institutional Review Board and performed under a waiver of explicit consent for a minimal risk study of existing electronic medical record data. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The raw data supporting the conclusions of this article will be made available by the authors upon reasonable requests, without undue reservation.