A new risk model for the evaluation of the thromboembolic milieu in patients with atrial fibrillation: the PALSE score

Background: The evaluation of thromboembolic risk is the cornerstone of atrial fibrillation (AF) management. Thromboembolic risk is associated with the presence of left atrial (LA) thrombus and spontaneous echo contrast (SEC), namely the thromboembolic milieu. Aims: We aimed to assess the predictors of the thromboembolic milieu in terms of LA thrombus and/ or SEC in patients with paroxysmal AF undergoing electrical cardioversion or catheter ablation, and to develop an effective risk model for detecting the thromboembolic milieu. Methods: We included a total of 434 patients with nonvalvular paroxysmal AF who underwent transesophageal echocardiography prior to cardioversion or catheter ablation. Results: In patients with the thromboembolic milieu, total protein and C‑reactive protein levels, LA diameter, and systolic pulmonary artery pressure (SPAP) were higher, while left ventricular ejection fraction (LVEF) was lower than in patients without the thromboembolic milieu. In a multivariate logistic regression analysis, age, total protein levels, LVEF, LA diameter, and SPAP were independent predictors of LA thrombus and/or SEC. In a receiver operating characteristic curve analysis, the optimal cutoff values for the discrimination of patients with the thromboembolic milieu were as follows: 60 years for age; 7.3 mg/dl for total protein; 40% for LVEF; 40 mm for LA diameter; and 35 mm Hg for SPAP. Based on these cutoff values, we developed a novel risk model, namely, the PALSE score. The area under the curve for the PALSE score was 0.833. Patients with a PALSE score lower than 1 did not show thrombus or spontaneous echo contrast. Conclusions: The PALSE score, which includes total protein levels, age, LA diameter, SPAP, and LVEF, seemed to accurately predict the presence of the thromboembolic milieu in patients with paroxysmal AF.