Introduction:
A scheduled catheter ablation for atrial fibrillation (AF) can be postponed due to preexisting thrombi in the left atrial appendage (LAA) identified by trans-esophageal echocardiography (TEE). We aimed to elucidate the predictive factor for thrombi formation.
Methods:
A total of 372 AF ablation candidates (male, 312; age, 59.8±10.4 years; CHA2DS2-VASc, 1.3±1.3; paroxysmal, 219) were evaluated. Warfarin was administered in 226 patients and dabigatran in 146 patients. A pre-procedural TEE identified thrombi in 24 patients (6.5%: postponed group). The patient background, pre-procedural blood sample data, transthoracic echocardiography (TTE), and TEE were compared between the performed and postponed groups.
Results:
Thu number of patients with hypertension (P=0.040), vascular disease (P<0.001), sleep apnea syndrome (P<0.001), and a TEE performed during AF (P=0.001) were significantly higher in the postponed group. The type of AF (paroxysmal, 11) and anticoagulants (warfarin, 16) did not differ between the groups. The age (P=0.007), CHA2DS2-VASc score (P=0.015), average flow velocity of the LAA measured using TEE (P<0.001), left ventricular ejection fraction (LVEF; P=0.006), size of the left atrium (LA; P=0.001) measured using TTE, and serum brain natriuretic peptide level (BNP; 82.4±81.4 pg/ml vs. 236.7±141.9; P<0.001) were significantly higher in the postponed group. The prothrombin time (P=0.087) and activated clotting time (P=0.178) did not differ. A multivariate analysis adjusted for the confounding factors such as the age, CHA2DS2-VASc score, LAA flow velocity, LA size and LVEF revealed that a serum BNP level of >135 pg/ml was the independent predictive factor for LAA thrombi (odds ratio, 14.178; 95% confidence interval [CI], 2.907 to 69.149; P=0.001). The area under the receiver operating characteristic (ROC) curve (AUC) for predicting a thrombus with the serum BNP level was 0.860 (95% CI: 0.775 to 0.944). The sensitivity and specificity for predicting a thrombus with a BNP value of >135 pg/ml were 81.8% and 83.6%, respectively.
Conclusions:
A serum BNP level of >135 pg/ml might be a noninvasive predictive factor for LAA thrombi in AF patients under anticoagulation therapy with warfarin and dabigatran.
Characterization of Plasma Brain Natriuretic Peptide Level in Patients with Type 2 Diabetes
