Major bleeding after left atrial appendage occlusion (LAAO) is common and linked to poorer outcomes, with risk driven mainly by patient characteristics, according to a recent trial that highlights the need for tailored risk assessment and post-procedural management.
LAAO is increasingly used to reduce the risk of stroke in patients with non-valvular atrial fibrillation who are unsuitable for long-term anticoagulation. However, bleeding remains a key complication, and its incidence, predictors and clinical impact are not fully characterised.
Published in the journal JAMA Cardiology, the Amplatzer Amulet LAA Occluder (Amulet IDE) randomised clinical trial aimed to evaluate the incidence, predictors, management and outcomes of major bleeding following LAAO.
The study included 1,833 patients who underwent attempted LAAO implantation. Drawn from a randomised cohort of 1,878 participants assigned 1:1 to the Amulet or Watchman device, the patients were followed for up to five years.
Major bleeding risk and LAAO
Over the follow-up period, 331 patients experienced major bleeding, corresponding to an annualised rate of 5.9%. The risk was found to be highest in the first six months after the LAAO procedure, with an annualised rate of 20.5%, before declining to 3.9% per year thereafter.
Most bleeding events were non-procedural (88.8%), with gastrointestinal the most common (57.5%). Other causes included trauma or falls (11.6%), pericardial effusion (8.4%) and intracranial haemorrhage (6.4%).
Patients who experienced major bleeding were typically older and had a higher comorbidity burden. Independent predictors included increasing age (hazard ratio [HR] 1.04), female sex (HR 1.25), diabetes (HR 1.26), prior bleeding (HR 1.93) and kidney disease (HR 2.15).
Notably, device type, discharge antithrombotic regimen and device-related factors were not associated with bleeding risk, suggesting that outcomes are primarily driven by patient characteristics rather than procedural variables.
At the time of the first bleeding event, 47.1% of patients were not receiving antithrombotic therapy, indicating that the risk persists even in the absence of pharmacological treatment.
Early bleeding and patient outcomes
Major bleeding after LAAO was associated with significantly worse clinical outcomes. At five years, the composite endpoint of stroke, systemic embolism or cardiovascular death occurred in 32.5% of patients with bleeding compared with 18.0% without.
Rates of stroke (14.7% vs 6.6%), cardiovascular death (24.4% vs 12.9%) and all-cause mortality (49.2% vs 25.4%) were all significantly higher in patients who experienced bleeding than those who did not.
Among 438 bleeding events, 25 were fatal, with intracranial and gastrointestinal haemorrhage the most common causes. Fatal events often occurred despite minimal or no antithrombotic therapy.
The first six months after LAAO were identified as a critical period of elevated bleeding risk, likely linked to intensified antithrombotic therapy. As treatment was de-escalated, bleeding rates declined, suggesting a potential long-term safety advantage of LAAO in high-risk populations.
The authors said their findings support individualised risk assessment, careful selection of antithrombotic regimens and close post-procedural monitoring. However, they noted that constraints, such as the use of an older Watchman device, non-randomised antithrombotic therapy at discharge and limited data on prior bleeding characteristics, must be considered.
Strategies such as gastrointestinal prophylaxis, fall prevention and optimisation of comorbidities were identified by the authors as potentially helping to mitigate risk during the early post-implant period, but they concluded that more work is needed to define optimal post-LAAO antithrombotic strategies and to evaluate newer device platforms.
Reference
Schmidt B et al. Incidence, predictors, management, and clinical impact of major bleeding following left atrial appendage occlusion: the Amulet IDE randomized clinical trial. JAMA Cardiol 2026; Mar 25:e260336.