title: Left atrial thrombus resolution in atrial fibrillation or flutter: Results of a prospective study with rivaroxaban (X-TRA) and a retrospective observational registry providing baseline data (CLOT-AF).
abstract: BACKGROUND
  Data on left atrial/left atrial appendage (LA/LAA) thrombus resolution after non-vitamin K antagonist (VKA) oral anticoagulant treatment are scarce. The primary objective of X-TRA was to explore the use of rivaroxaban for the resolution of LA/LAA thrombi in patients with nonvalvular atrial fibrillation (AF) or atrial flutter, with the CLOT-AF registry providing retrospective data after standard-of-care therapy in this setting.
  
  
  METHODS
  X-TRA was a prospective, single-arm, open-label, multicenter study that investigated rivaroxaban treatment for 6 weeks for LA/LAA thrombus resolution in patients with nonvalvular AF or atrial flutter and LA/LAA thrombus confirmed at baseline on a transesophageal echocardiogram (TEE). CLOT-AF retrospectively collected thrombus-related patient outcome data after standard-of-care anticoagulant treatment for 3 to 12 weeks in patients with nonvalvular AF or atrial flutter who had LA/LAA thrombi on TEE recorded in their medical file.
  
  
  RESULTS
  In X-TRA, patients were predominantly (95.0%) from Eastern European countries. The adjudicated thrombus resolution rate was 41.5% (22/53 modified intention-to-treat [mITT] patients, 95% CI 28.1%-55.9%) based on central TEE assessments. Resolved or reduced thrombus was evident in 60.4% (32/53 mITT patients, 95% CI 46.0%-73.6%) of patients. In CLOT-AF, the reported thrombus resolution rate was 62.5% (60/96 mITT patients, 95% CI 52.0%-72.2%) and appeared better in Western European countries (34/50; 68.0%) than in Eastern European countries (26/46; 56.5%).
  
  
  CONCLUSIONS
  X-TRA is the first prospective, multicenter study examining LA/LAA thrombus resolution with a non-VKA oral anticoagulant in VKA-naïve patients or in patients with suboptimal VKA therapy. Rivaroxaban could be a potential option for the treatment of LA/LAA thrombi.
authors: University of Birmingham Institute of Cardiovascular Sciences, City Hospital, Birmingham, United Kingdom; Aalborg Thrombosis Research Unit, Department of Clinical Medicine, Aalborg University, Aalborg, Denmark. Electronic address: g.y.h.lip@bham.ac.uk.
authors: Gregory Y H
authors: GY
authors: Lip
authors: Department of Medicine II, Heart Center Bonn, University Hospital Bonn, Bonn, Germany.
authors: Christoph
authors: C
authors: Hammerstingl
authors: Department of Cardiology, Hospital Clínico Universitario Virgen de la Arrixaca, IMIB-Arrixaca, Murcia, Spain.
authors: Francisco
authors: F
authors: Marin
authors: Humanitas Clinical and Research Centre, Rozzano, MI, Italy.
authors: Riccardo
authors: R
authors: Cappato
authors: Global Medical Affairs, Bayer Pharma AG, Berlin, Germany.
authors: Isabelle Ling
authors: IL
authors: Meng
authors: Global Research and Development Statistics, Bayer Pharma AG, Berlin, Germany.
authors: Bodo
authors: B
authors: Kirsch
authors: Global Medical Affairs, Bayer Pharma AG, Berlin, Germany.
authors: Martin
authors: M
authors: van Eickels
authors: Cardiology Department, Assistance publique-Hôpitaux de Paris and université Pierre-et-Marie-Curie, Saint-Antoine University and Medical School, Paris, France.
authors: Ariel
authors: A
authors: Cohen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020517:Atrial Appendage; D001281:Atrial Fibrillation / Q000150:complications*; D001282:Atrial Flutter / Q000150:complications*; D017548:Echocardiography, Transesophageal; D065427:Factor Xa Inhibitors / Q000627:therapeutic use*; D005260:Female; D006325:Heart Atria; D006331:Heart Diseases / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012042:Registries; D012189:Retrospective Studies; D000069552:Rivaroxaban / Q000627:therapeutic use*; D013927:Thrombosis / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000209:etiology
chemical_list: D065427:Factor Xa Inhibitors; D000069552:Rivaroxaban