title: Risk factors for thrombus formation on the Amplatzer Cardiac Plug after left atrial appendage occlusion.
abstract: OBJECTIVE
  This study sought to identify risk factors for thrombus formation on the Amplatzer Cardiac Plug (ACP) (St. Jude Medical, St. Paul, Minnesota) after left atrial appendage occlusion.
  
  
  BACKGROUND
  Left atrial appendage occlusion with the ACP aims to reduce the risk of embolic stroke and bleeding complications associated with vitamin K antagonists in patients with atrial fibrillation.
  
  
  METHODS
  We performed transesophageal echocardiography before discharge and after 3, 6, and 12 months in 34 patients with atrial fibrillation undergoing ACP implantation and receiving dual antiplatelet therapy. Clinical, echocardiographic, and hemostaseological parameters were retrospectively analyzed to identify risk factors for thrombus formation.
  
  
  RESULTS
  Three patients had thrombi before discharge, 3 more at the 3-month follow-up. No differences were found in left atrial volume, left atrial appendage velocity, spontaneous echo contrast, transmitral gradient, or mitral regurgitation between patients without or with thrombi. CHADS2 (Congestion, Hypertension, Age, Diabetes, and Stroke) score (2.0 ± 1.1 vs. 4.3 ± 1.0), CHA2DS2-VASc (CHADS2 plus Vascular Disease and Sex Category) score (5.2 ± 1.3 vs. 6.8 ± 0.8), and pre-interventional platelet count (215.9 ± 63.9/nl vs. 282.5 ± 84.4/nl) were higher and ejection fraction (50.6 ± 11.4% vs. 39.7 ± 10.6%) lower in those with thrombi. Factor 2, factor 5, or methylenetetrahydrofolate reductase mutations and genetic variants associated with reduced clopidogrel activity were not more frequent in patients with thrombi.
  
  
  CONCLUSIONS
  Transesophageal echocardiography identified 17.6% of patients with thrombus formation on the ACP despite dual antiplatelet therapy. CHADS2 and CHA2DS2-VASc scores, platelet count, and ejection fraction are risk factors for such thrombus formation.
authors.affiliation: Department of Cardiology, West-German Heart Center Essen, University Hospital Essen, University Duisburg-Essen, Essen, Germany. bjoern.plicht@uk-essen.de
authors.forename: Bjoern
authors.initials: B
authors.lastname: Plicht
authors.forename: Thomas F M
authors.initials: TF
authors.lastname: Konorza
authors.forename: Philipp
authors.initials: P
authors.lastname: Kahlert
authors.forename: Fadi
authors.initials: F
authors.lastname: Al-Rashid
authors.forename: Hagen
authors.initials: H
authors.lastname: Kaelsch
authors.forename: Rolf Alexander
authors.initials: RA
authors.lastname: Jánosi
authors.forename: Thomas
authors.initials: T
authors.lastname: Buck
authors.forename: Hagen S
authors.initials: HS
authors.lastname: Bachmann
authors.forename: Winfried
authors.initials: W
authors.lastname: Siffert
authors.forename: Gerd
authors.initials: G
authors.lastname: Heusch
authors.forename: Raimund
authors.initials: R
authors.lastname: Erbel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D020517:Atrial Appendage / Q000000981:diagnostic imaging / Q000503:physiopathology; D001281:Atrial Fibrillation / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000295:instrumentation*; D016009:Chi-Square Distribution; D004359:Drug Therapy, Combination; D019560:Echocardiography, Three-Dimensional; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans; D008297:Male; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D011474:Prosthesis Design; D012189:Retrospective Studies; D012307:Risk Factors; D055989:Septal Occluder Device / Q000009:adverse effects*; D013927:Thrombosis / Q000175:diagnosis / Q000209:etiology* / Q000517:prevention & control; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors