title: Safety and Use of Anticoagulation After Aortic Valve Replacement With Bioprostheses: A Meta-Analysis.
abstract: The American College of Cardiology guidelines recommend 3 months of anticoagulation after replacement of the aortic valve with a bioprosthesis. However, there remains great variability in the current clinical practice and conflicting results from clinical studies. To assist clinical decision making, we pooled the existing evidence to assess whether anticoagulation in the setting of a new bioprosthesis was associated with improved outcomes or greater risk of bleeding.
  
  
  
  We searched the PubMed database from the inception of these databases until April 2015 to identify original studies (observational studies or clinical trials) that assessed anticoagulation with warfarin in comparison with either aspirin or no antiplatelet or anticoagulant therapy. We included the studies if their outcomes included thromboembolism or stroke/transient ischemic attacks and bleeding events. Quality assessment was performed in accordance with the Newland Ottawa Scale, and random effects analysis was used to pool the data from the available studies. I(2) testing was done to assess the heterogeneity of the included studies. After screening through 170 articles, a total of 13 studies (cases=6431; controls=18210) were included in the final analyses. The use of warfarin was associated with a significantly increased risk of overall bleeding (odds ratio, 1.96; 95% confidence interval, 1.25-3.08; P<0.0001) or bleeding risk at 3 months (odds ratio, 1.92; 95% confidence interval, 1.10-3.34; P<0.0001) compared with aspirin or placebo. With regard to composite primary outcome variables (risk of venous thromboembolism, stroke, or transient ischemic attack) at 3 months, no significant difference was seen with warfarin (odds ratio, 1.13; 95% confidence interval, 0.82-1.56; P=0.67). Moreover, anticoagulation was also not shown to improve outcomes at time interval >3 months (odds ratio, 1.12; 95% confidence interval, 0.80-1.58; P=0.79).
  
  
  
  Contrary to the current guidelines, a meta-analysis of previous studies suggests that anticoagulation in the setting of an aortic bioprosthesis significantly increases bleeding risk without a favorable effect on thromboembolic events. Larger, randomized controlled studies should be performed to further guide this clinical practice.
authors.affiliation: From the Department of Internal Medicine, Cleveland Clinic, OH (H.R., S.A.R.A.); Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, OH (S.A.R.A., S.R.); Department of Internal Medicine, Dow University of Health Sciences, Karachi, Pakistan (M.S.K.); Department of Internal Medicine, Bronx Lebanon Hospital, New York, NY (T.R.); Department of Cardiovascular Medicine, Mercy Saint Vincent Medical Center, Toledo, OH (F.K.L.); Department of Cardiovascular Medicine, University of Louisville, KY (A.R.K.); Department of Internal Medicine, University of Arizona, Tucson (I.B.R.); and Department of Cardiovascular Medicine, Duke University, Durham, NC (R.A.K.). riazh@ccf.org.
authors.forename: Haris
authors.initials: H
authors.lastname: Riaz
authors.affiliation: From the Department of Internal Medicine, Cleveland Clinic, OH (H.R., S.A.R.A.); Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, OH (S.A.R.A., S.R.); Department of Internal Medicine, Dow University of Health Sciences, Karachi, Pakistan (M.S.K.); Department of Internal Medicine, Bronx Lebanon Hospital, New York, NY (T.R.); Department of Cardiovascular Medicine, Mercy Saint Vincent Medical Center, Toledo, OH (F.K.L.); Department of Cardiovascular Medicine, University of Louisville, KY (A.R.K.); Department of Internal Medicine, University of Arizona, Tucson (I.B.R.); and Department of Cardiovascular Medicine, Duke University, Durham, NC (R.A.K.).
authors.forename: Shehab Ahmad Redha
authors.initials: SA
authors.lastname: Alansari
authors.affiliation: From the Department of Internal Medicine, Cleveland Clinic, OH (H.R., S.A.R.A.); Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, OH (S.A.R.A., S.R.); Department of Internal Medicine, Dow University of Health Sciences, Karachi, Pakistan (M.S.K.); Department of Internal Medicine, Bronx Lebanon Hospital, New York, NY (T.R.); Department of Cardiovascular Medicine, Mercy Saint Vincent Medical Center, Toledo, OH (F.K.L.); Department of Cardiovascular Medicine, University of Louisville, KY (A.R.K.); Department of Internal Medicine, University of Arizona, Tucson (I.B.R.); and Department of Cardiovascular Medicine, Duke University, Durham, NC (R.A.K.).
authors.forename: Muhammad Shahzeb
authors.initials: MS
authors.lastname: Khan
authors.affiliation: From the Department of Internal Medicine, Cleveland Clinic, OH (H.R., S.A.R.A.); Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, OH (S.A.R.A., S.R.); Department of Internal Medicine, Dow University of Health Sciences, Karachi, Pakistan (M.S.K.); Department of Internal Medicine, Bronx Lebanon Hospital, New York, NY (T.R.); Department of Cardiovascular Medicine, Mercy Saint Vincent Medical Center, Toledo, OH (F.K.L.); Department of Cardiovascular Medicine, University of Louisville, KY (A.R.K.); Department of Internal Medicine, University of Arizona, Tucson (I.B.R.); and Department of Cardiovascular Medicine, Duke University, Durham, NC (R.A.K.).
authors.forename: Talha
authors.initials: T
authors.lastname: Riaz
authors.affiliation: From the Department of Internal Medicine, Cleveland Clinic, OH (H.R., S.A.R.A.); Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, OH (S.A.R.A., S.R.); Department of Internal Medicine, Dow University of Health Sciences, Karachi, Pakistan (M.S.K.); Department of Internal Medicine, Bronx Lebanon Hospital, New York, NY (T.R.); Department of Cardiovascular Medicine, Mercy Saint Vincent Medical Center, Toledo, OH (F.K.L.); Department of Cardiovascular Medicine, University of Louisville, KY (A.R.K.); Department of Internal Medicine, University of Arizona, Tucson (I.B.R.); and Department of Cardiovascular Medicine, Duke University, Durham, NC (R.A.K.).
authors.forename: Sajjad
authors.initials: S
authors.lastname: Raza
authors.affiliation: From the Department of Internal Medicine, Cleveland Clinic, OH (H.R., S.A.R.A.); Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, OH (S.A.R.A., S.R.); Department of Internal Medicine, Dow University of Health Sciences, Karachi, Pakistan (M.S.K.); Department of Internal Medicine, Bronx Lebanon Hospital, New York, NY (T.R.); Department of Cardiovascular Medicine, Mercy Saint Vincent Medical Center, Toledo, OH (F.K.L.); Department of Cardiovascular Medicine, University of Louisville, KY (A.R.K.); Department of Internal Medicine, University of Arizona, Tucson (I.B.R.); and Department of Cardiovascular Medicine, Duke University, Durham, NC (R.A.K.).
authors.forename: Faraz Khan
authors.initials: FK
authors.lastname: Luni
authors.affiliation: From the Department of Internal Medicine, Cleveland Clinic, OH (H.R., S.A.R.A.); Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, OH (S.A.R.A., S.R.); Department of Internal Medicine, Dow University of Health Sciences, Karachi, Pakistan (M.S.K.); Department of Internal Medicine, Bronx Lebanon Hospital, New York, NY (T.R.); Department of Cardiovascular Medicine, Mercy Saint Vincent Medical Center, Toledo, OH (F.K.L.); Department of Cardiovascular Medicine, University of Louisville, KY (A.R.K.); Department of Internal Medicine, University of Arizona, Tucson (I.B.R.); and Department of Cardiovascular Medicine, Duke University, Durham, NC (R.A.K.).
authors.forename: Abdur Rahman
authors.initials: AR
authors.lastname: Khan
authors.affiliation: From the Department of Internal Medicine, Cleveland Clinic, OH (H.R., S.A.R.A.); Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, OH (S.A.R.A., S.R.); Department of Internal Medicine, Dow University of Health Sciences, Karachi, Pakistan (M.S.K.); Department of Internal Medicine, Bronx Lebanon Hospital, New York, NY (T.R.); Department of Cardiovascular Medicine, Mercy Saint Vincent Medical Center, Toledo, OH (F.K.L.); Department of Cardiovascular Medicine, University of Louisville, KY (A.R.K.); Department of Internal Medicine, University of Arizona, Tucson (I.B.R.); and Department of Cardiovascular Medicine, Duke University, Durham, NC (R.A.K.).
authors.forename: Irbaz Bin
authors.initials: IB
authors.lastname: Riaz
authors.affiliation: From the Department of Internal Medicine, Cleveland Clinic, OH (H.R., S.A.R.A.); Department of Cardiothoracic Surgery, Heart and Vascular Institute, Cleveland Clinic, OH (S.A.R.A., S.R.); Department of Internal Medicine, Dow University of Health Sciences, Karachi, Pakistan (M.S.K.); Department of Internal Medicine, Bronx Lebanon Hospital, New York, NY (T.R.); Department of Cardiovascular Medicine, Mercy Saint Vincent Medical Center, Toledo, OH (F.K.L.); Department of Cardiovascular Medicine, University of Louisville, KY (A.R.K.); Department of Internal Medicine, University of Arizona, Tucson (I.B.R.); and Department of Cardiovascular Medicine, Duke University, Durham, NC (R.A.K.).
authors.forename: Richard A
authors.initials: RA
authors.lastname: Krasuski
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001021:Aortic Valve / Q000503:physiopathology / Q000601:surgery*; D001241:Aspirin / Q000008:administration & dosage* / Q000009:adverse effects; D001705:Bioprosthesis; D004334:Drug Administration Schedule; D006349:Heart Valve Diseases / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation*; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D002546:Ischemic Attack, Transient / Q000209:etiology / Q000517:prevention & control; D016017:Odds Ratio; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage; D011474:Prosthesis Design; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000209:etiology / Q000517:prevention & control; D013997:Time Factors; D016896:Treatment Outcome; D054556:Venous Thromboembolism / Q000209:etiology / Q000517:prevention & control; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D000925:Anticoagulants; D010975:Platelet Aggregation Inhibitors; D014859:Warfarin; D001241:Aspirin
keywords: anticoagulants; bioprosthesis; meta-analysis; platelet aggregation inhibitors; surgical aortic valve replacement; transcatheter aortic valve replacement