Thromboembolic events due to left atrial appendage (LAA)
thrombosis are the main complication of non-valvular
atrial fibrillation (NVAF). Although
anticoagulants are effective in patients with NVAF, a minimal residual thromboembolic risk persists. Little is known about the prevalence of LAA
thrombus and the rate of resolution after the recommended period of anticoagulation
therapy, including
vitamin K antagonists (VKA),
heparin, and non-
vitamin K antagonist oral
anticoagulants (NOACs).
METHODS AND RESULTS: We aimed to study the prevalence of LAA
thrombus in an unselected cohort of patients undergoing transesophageal echocardiogram (TEE), and the determinants of LAA
thrombus resolution. We retrospectively analyzed 8888 consecutive TEEs performed over five years in two high-volume centers and included all patients with LAA
thrombus. A total of 265 patients (3%) had an LAA
thrombus. Among these, 97% presented with AF. Fifty-eight percent of patients were on
anticoagulants at least three weeks before the diagnosis. After the LAA
thrombus diagnosis, VKAs were prescribed in 52%,
heparin in 18.5%, and
NOAC in 27% of patients. Among the 183 patients with repeat TEE, performed at (25-75th) 39 days (21-84), 67% showed resolution of the LAA
thrombus. Although the rate of
thrombus resolution was higher in patients treated with NOACs (NOACs 71%, VKA 66%,
Heparin 60%) the difference between
anticoagulants was statistically non-significant (VKA, OR 0.9, p = 0.83;
NOAC, OR 1.23, p = 0.42;
heparin, OR 0.69, p = 0.35). Thus, NOACs were demonstrated to be at least as effective as other
anticoagulants in the rate of LAA
thrombus resolution. Upon multivariate-adjusted analysis, higher LAA emptying velocities were the only predictor of
thrombus resolution. In conclusion, the majority of patients were already on
anticoagulants. NOACs could be at least as effective as other
anticoagulants, yielding an LAA
thrombus resolution in two-thirds of patients. This may have clinical relevance, especially in patients undergoing
cardioversion or
catheter ablation.