Abstract 1172: Chads2 and Echocardiographic Predictors of Left Atrial Thrombus in Non-valvular Atrial Fibrillation
Stroke in patients with atrial fibrillation (AF) encompasses mechanisms beyond embolization from a left atrial thrombus (LAT). To determine whether the CHADS-2 risk assessment tool distinguishes patients with left atrial source of embolism from non-cardioembolic stroke mechanisms, the Mayo Clinic prospective Echocardiography Laboratory and Cardioversion Unit Database was used to identify AF patients not previously treated with warfarin who were found to have LAT present (cases) or absent (controls) by transesophageal echocardiography (TEE). Variables of CHADS2 system [congestive heart failure (CHF), hypertension, age>75, diabetes mellitus, history of stroke/transient ischemic attack (TIA)], and echocardiographic findings [left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), left atrium diameter size (LADS)] were compared between the two groups.
Results: One hundred seven AF patients with LAT (mean age 72±11 years; 39%women) were compared to 422 without LAT (mean age 71±13 years; 36%women). Diabetes mellitus and prior stroke/TIA were more common in cases than controls. Atrial enlargement and decreased LV systolic function, but not LV enlargement was associated with the presence of LAT. The mean CHADS2 score was low, but significantly higher for cases (average 2.8±1.6; median 3.0; range 0 – 6) compared to controls (average 1.6±1.3; median 1.0; range 0 – 6). However, for those patients with TEE confirmed LAT, the CHADS2 score varied considerably with 34% of CHADS2 scores between 0–1 and only 12.9% of those with high scores (5 or 6). These data show that not all elements of CHADS2 scheme discriminate LAT-related stroke. Reduced LVEF, left atrial size and heart failure remain the strongest risk variables and may provide mechanistic insight into thrombogenesis in atrial fibrillation.