Clinical Characteristics And Anticoagulation Treatment Of Atrial Fibrillation Patients With Severe Left Atrial Spontaneous Echo Contrast Or Left Atrial Thrombus

Objective:1.Severe left atrial spontaneous echo contrast（SLASEC）is considered the prior stage to thrombosis and a high risk factor for thrombotic events.Studies have suggested an effect of D-dimer blood concentration on exclusion of left atrial thrombus（LAT）,but it remains unclear whether D-dimer concentrations differ between atrial fibrillation（AF）patients with SLASEC or LAT.2.The administration of vitamin K antagonists（VKA）has been the mainstay in the treatment of LAT.Data comparing dabigatran with rivaroxaban regarding resolution of left atrial/left atrial appendage（LA/LAA）thrombus in patients with nonvalvular AF are scarce.Methods:1.Nonvalvular AF patients scheduled to undergo catheter ablation or cardioversion in Shanghai Ruijin Hospital between January 2017 and July 2020 were screened for this prospective study.All patients underwent transesophageal echocardiography（TEE）to detect SLASEC or LAT.D-dimer concentrations were measured at the time of TEE.Clinical data including CHA₂DS₂-VASc score were evaluated.Major complications with thromboembolism in the SLASEC group were followed up at least 6 months after therapy.2.This retrospective study enrolled nonvalvular AF patients scheduled to undergo catheter ablation or cardioversion in Shanghai Ruijin Hospital between January 2014 and January 2019.Altogether,34 patients with LA/LAA thrombus detected by TEE were enrolled.Among them,12 patients were treated with dabigatran 150mg bid and the other 22 with rivaroxaban 20mg qd.Follow-up TEE was performed within≥3 weeks to<6months of the initial TEE to evaluate resolution of the LA/LAA thrombus.Results:1.Among 920 consecutively enrolled nonvalvular AF patients,30 patients with SEC grade0,35 patients with SLASEC and 22 patients with LAT were included.D-dimer concentration and CHA₂DS₂-VASc score were significantly lower in the SLASEC group compared with the LAT group（D-dimer:0.26±0.13 vs.0.86±0.9mg/L,P<0.05;CHA₂DS₂-VASc score:2.3±0.9 vs.3.1±1.5,P=0.02）.The cut-off value for D-dimer concentration（0.285mg/L）had sensitivity of 77.3%and specificity of 80.0%for prediction of LAT.D-dimer concentration showed a decreasing trend with a significant difference（0.42±0.22 vs.0.33±0.18mg/L,P=0.03）for 9 patients in the LAT group after complete thrombus resolution by anticoagulation treatment.No major or fatal bleeding,ischemic stroke,or systemic thromboembolism events occurred in the SLASEC group during the6-month follow-up.2.Baseline patient characteristics were similar in the rivaroxaban and dabigatran group.Overall,18 patients（81.8%）in the rivaroxaban group had complete thrombus resolution after 70.3±22.1 treatment days,and 10 patients（83.3%）in the dabigatran group had complete thrombus resolution after 69.3±47.9 treatment days.There was no significant difference in anticoagulant treatment time and resolution rate between the groups.TEE showed that the average length,width,and area of thrombus significantly decreased in both groups after treatment,although there was no significant difference in the amount of change in these parameters between the two groups after treatment（P=0.6）.Undissolved thrombus in two patients in the rivaroxaban group did dissolve after switching to dabigatran.Conclusions:1.This study demonstrated a significantly lower D-dimer concentration and CHA₂DS₂-VASc score in AF patients with SLASEC than in those with LAT.The D-dimer cut-off value（0.285 mg/L）can be used as an effective reference index to distinguish the pre-thrombotic state of LAT from LAT.D-dimer blood concentration may be a predictor of LAT thrombolysis.2.The results suggest that both dabigatran and rivaroxaban are potential options for treating LA/LAA thrombus in patients with NVAF.Dabigatran could be an alternative option for the resolution of LA/LAA thrombus“resistant”to rivaroxaban.