An observational study in Percutaneous Left Atrial Appendage Occlusion (LAAO), Device-related Thrombus (DRT) and Thromboembolic Event, sponsored by Institut universitaire de cardiologie et de pneumologie de Québec, University Laval. Not yet recruiting at 1 site in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-03-24.
Sponsored by Institut universitaire de cardiologie et de pneumologie de Québec, University Laval · Observational
This study is a prospective, multicenter international trial aimed at assessing the actual incidence, identifying associated factors, and evaluating the clinical consequences of both persistent and recurrent device-related thrombus (DRT) following percutaneous left atrial appendage occlusion (LAAO).
While LAAO has shown efficacy in reducing the risk of stroke, device-related thrombus (DRT) remains a significant concern. The reported incidence of DRT varies, and it is associated with an elevated risk of ischemic stroke and death. The study highlights that persistent and recurrent DRT pose higher risks of thromboembolic events, and current data come from retrospective studies with non-standardized imaging follow-up protocols. The timing of imaging follow-up is crucial, and the study notes discrepancies in recommendations from expert statements. The EHRA/EAPCI suggests imaging at specific intervals post-procedure, while the SCAI/HRS recommends repeat imaging at shorter intervals to assess DRT resolution. The study underscores the need for dedicated prospective data to accurately determine the incidence, factors, and clinical impact of persistent and recurrent DRT after LAAO.
BACKGROUND: Percutaneous left atrial appendage occlusion (LAAO) has emerged as a nonpharmacological alternative for stroke prevention in patients with non-valvular atrial fibrillation ineligible for chronic anticoagulation therapy. Large real-world observational studies have consistently reported the efficacy of LAAO in reducing the risk of ischemic stroke and systemic embolism, compared to predicted rates, without the need for anticoagulants. Despite ongoing refinement in LAAO procedural technique, significant challenges persist. Notably, device-related thrombus (DRT) remains the main concern after LAAO. The reported incidence rate varies, ranging from 3% to 7%, and has been associated with an elevated risk of ischemic stroke and all-cause death following LAAO. Several risk factors have been identified with DRT occurrence, most of which are non-modifiable. The diagnosis of DRT is followed by an intensification of the antithrombotic treatment. However, not all DRT are resolved, with a significant number persisting or recurring upon withdrawal of anticoagulation therapy. In these situations, the antithrombotic treatment must be maintained, increasing the risk of bleeding, and mitigating the potential benefits of LAAO.
Both persistent and recurrent DRT have been linked to an increased risk of thromboembolic events when compared to resolved DRT. In the pooled analysis of data from the PROTECT-AF and PREVAIL trials, around 12% of embolic events in patients with DRT occurred in the presence of multiple DRT episodes. The incidence of persistent DRT has been reported in one out of three patients diagnosed with DRT, with DRT recurrence occurring in one out of five patients. However, the real incidence of persistent and recurrent DRT is uncertain, as current data come from retrospective studies with non-standardized imaging follow-up protocols. This situation leads to a significant number of missed cases, increases the risk of bias, and likely underestimates the rate of persistent and recurrent DRT. The timing of the imaging follow-up can significantly affect the incidence of DRT. In consecutive patients examined through a pre-specified protocol, the incidence of specific findings would be much more accurate compared to imaging examinations based exclusively on a single adverse clinical event, where the real incidence and clinical associations cannot be accurately determined.
The EHRA/EAPCI expert LAAO statement recommends imaging within 6-24 weeks and then 12 months post-procedure, with no mention of imaging follow-up in case of persistent or recurrent DRT. In contrast, the recent SCAI/HRS expert consensus statement on transcatheter LAAO suggests that repeat imaging at 45- to 90-day intervals can be conducted to assess for DRT resolution and consider the eventual cessation of anticoagulation, although there is no evidence that support this recommendation. Finally, considering the substantial rate of recurrent DRT and its clinical implications, a long-term and sequential imaging follow-up strategy may be warranted. Therefore, there is an unmet need for dedicated prospective data to determine the real incidence, related factors, and clinical impact of persistent and recurrent DRT after LAAO.
288 studies on the registry are indexed under Thromboembolism; 42 are open to participants now.
This study's planned enrollment of 100 is below the median of 440 across 121 observational studies indexed under Thromboembolism.
Browse Thromboembolism studies →Institut universitaire de cardiologie et de pneumologie de Québec, University Laval is the lead sponsor of 15 studies on the registry; 9 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Patients undergoing LAAO with a probable/definite diagnosis of DRT detected by transesophageal echocardiography (TEE) or cardiac computed tomography (CT).
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 with diagnosis of probable/definite DRT after LAAO detected by transesophageal echocardiography (TEE) or cardiac computed tomography (CT). In all patients after the LAAO procedure, a first imaging evaluation at 45 to 90 days, and a second imaging evaluation at 12 months is recommended. In case of DRT diagnosis, and following the recent SCAI/HRS recommendations, a repeat imaging at 45- to 90-day intervals is recommended to assess for DRT resolution with eventual cessation of anticoagulation. In case of DRT resolution, a sequential imaging evaluation at ±90-day, ±180-day, and ±365 days after the imaging test where DRT was resolved is recommended
Thromboembolic events (ischemic stroke, systemic embolism)
Incidence of and thromboembolic events (ischemic stroke, systemic embolism) associated with persistent/recurrent DRT after LAAO
Time frame: 1-month, 6-month, 1-year, 2-year
Start is estimated for Dec 2026; primary completion for Jan 2028, 13 months later.
Of 46 observational studies under Thromboembolism, half reached primary completion within 39 months of starting (the median), counting those still running; a quarter within 24 and three quarters within 65. This study's planned 13 months is below that.
How these figures are worked out, and which studies are left out of them.
This study is not yet recruiting, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Institut universitaire de cardiologie et de pneumologie de Québec, University Laval