Biomarker changes after surgical left atrial appendage occlusion: a substudy of LAAOS III

The Left Atrial Appendage Occlusion Study (LAAOS) III showed that surgical left atrial appendage occlusion (LAAO) reduced ischemic stroke or systemic embolism (SE) in patients with atrial fibrillation undergoing cardiac surgery.

To explore whether LAAO changes levels of circulating biomarkers of coagulation activation, inflammation, hemodynamic stress or myocardial injury after surgical LAAO.

In this single-center biomarker substudy of LAAOS III, D-dimer, C-reactive protein, interleukin-6, N-terminal pro-B-type natriuretic peptide, high-sensitivity cardiac troponin T, and heart-type fatty acid-binding protein were measured at baseline and at 30 days and/or 1 year in patients randomized to LAAO or no LAAO. Biomarker levels and changes from baseline were compared by treatment group. Exploratory landmark Cox models assessed associations between biomarker changes and subsequent stroke/SE after the 30-day and 1-year landmarks.

Baseline samples were available for 208 participants, 30-day samples for 170, and 1-year samples for 123. Baseline biomarker levels were similar between groups. At 30 days, all measured biomarkers increased without between-group differences. At 1 year, most biomarkers had returned toward baseline. Too few events occurred after the 30-day and 1-year landmarks to support reliable analyses on biomarker changes and subsequent stroke/SE.

Surgical LAAO was not associated with consistent changes in circulating biomarkers over 1 year in this exploratory substudy, despite its clinical benefit. The lack of a detectable effect on the circulating biomarkers evaluated in this study does not provide a mechanistic explanation for the clinical benefit of surgical LAAO.