Imaging-defined residual risk after left atrial appendage occlusion: from device surveillance to antithrombotic and...

Left atrial appendage occlusion (LAAO) is increasingly used for stroke prevention in selected patients with nonvalvular atrial fibrillation, particularly when long-term oral anticoagulation is unsuitable, poorly tolerated, or clinically undesirable. Although contemporary trials and registries have demonstrated favorable procedural success and long-term outcomes, post-implantation imaging findings continue to create uncertainty during follow-up. These findings include device-related thrombus (DRT), hypoattenuated thickening (HAT), peri-device leak (PDL), residual left atrial appendage patency, and device-appendage mismatch.

This review reframes post-LAAO imaging findings as imaging-defined residual risk markers and proposes an evidence-informed framework that explicitly links management considerations to their principal supporting evidence sources.

DRT is uncommon but clinically relevant, with event rates of ischemic stroke or systemic embolism of approximately 6.3 per 100 patient-years in patients with DRT vs. 1.7 per 100 patient-years in those without DRT. HAT is a heterogeneous imaging phenotype ranging from expected healing to thrombus-like surface abnormality. CCTA detects residual appendage patency and PDL more frequently than TEE, but greater sensitivity does not automatically confer clinical actionability. This review organizes post-LAAO findings into three domains: device surface abnormality, residual communication, and device-appendage geometry.

Post-LAAO imaging should move beyond binary device surveillance toward risk-weighted interpretation. Most management implications remain supported by expert consensus, observational evidence, and registry data rather than prospective trials. Outcome-linked imaging thresholds and prospective validation are required before imaging-defined residual risk can be incorporated into clinical decision pathways.