Poor enhancement pattern of left atrial appendage in cardiac computed tomography is associated with stroke in persistent atrial fibrillation patients

Background: In atrial fibrillation (AF) patients, the left atrial appendage (LAA) is the major source of thrombi. We assessed the hypothesis that poor contrast enhancement in the LAA during the early phase of cardiac computed tomography (CT) predicts a high risk of thrombus formation, leading to cardiogenic stroke. Methods: We studied 147 consecutive patients with chronic AF who underwent cardiac CT. Three different patterns of medium contrast enhancement in the LAA were used to categorize the stroke risk: poor, intermediate, and good enhancement pattern. Results: The CT scans of 147 patients were analyzed (age, 69 +/- 9 years; 82% men; 43% with a CHA(2)DS(2)-VASc score >= 2). Seventy-two patients (49%) had a poor enhancement LAA enhancement pattern, 33 (22%) had an intermediate enhancement pattern, and 42 (29%) had a good enhancement pattern. Of the 147 patients, 58 (39%) had a history of ischemic stroke or transient ischemic attack (TIA). The prevalence of a stroke history associated with each pattern was 58%, 27%, and 17%, respectively (P<0.001). After controlling for the CHADS(2) or CHA(2)DS(2)-VASc score and the ejection fraction using a multivariable logistic model, the poor enhancement pattern was found to be significantly more likely to be associated with a stroke history than other patterns [odds ratio (OR): 5.3; 95% confidence interval (CI): 2.5-11.1; P<0.0001]. Conclusions: The LAA enhancement pattern observed using cardiac CT is associated with the risk of stroke. Poor enhancement in the LAA suggests a potential high risk of stroke.