title: Is low anticoagulation intensity more beneficial for patients with bileaflet mechanical mitral valves? A meta-analysis.
abstract: BACKGROUND
  For the mitral valve replacement (MVR) using the lowest thrombogenic risk bileaflet valves (St. Jude Medical [St Paul, MN, USA], Carbomedics [Austin, TX, USA] and On-X [Austin, TX, USA]), excellent results can be achieved by adopting the anticoagulation intensity (median INR<2.5) which is lower than the recommended intensity (INR:2.5~3.5). Our aim was to provide a pooled estimate of potential benefit from clinical studies using low anticoagulation intensity and high intensity in these patients.
  
  
  METHODS
  Relevant studies published before February 2014 were searched through a number of digital databases (MEDLINE, EMBASE, Cochrane Library, etc.). They were pooled by SPSS19.0 using the random effect method in three fields: occurrence rate of major thromboembolism, major hemorrhage and major total events. Fourteen studies with 3595 patients were included. The follow-up period was 12,846.6 patient-years.
  
  
  RESULTS
  Pooled estimates indicated reduction in major hemorrhage (RR:0.420, 95%CI: 0.296~0.595, P<0.001) and major total events (RR: 0.738, 95%CI: 0.604~0.902, P=0.003) in the low intensity group. No difference was noted in major thromboembolism (RR: 1.045, 95%CI: 0.814~1.341, P=0.75).
  
  
  CONCLUSIONS
  Compared with the recommended high intensity, low anticoagulation intensity (median INR<2.5) may be more beneficial for the MVR patients using the lowest thrombogenic risk bileaflet valves. We recommended an INR between 2.0 and 2.5, with a median INR of 2.3 for these MVR patients.
authors.affiliation: Division of Cardiac Surgery, the First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China - himybox@126.com.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Xu
authors.forename: Zhi P
authors.initials: ZP
authors.lastname: Wang
authors.forename: Jing S
authors.initials: JS
authors.lastname: Ou
authors.forename: Sheng L
authors.initials: SL
authors.lastname: Yin
authors.forename: Li J
authors.initials: LJ
authors.lastname: Liu
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D001777:Blood Coagulation / Q000187:drug effects; D006350:Heart Valve Prosthesis; D006470:Hemorrhage / Q000517:prevention & control*; D006801:Humans; D019934:International Normalized Ratio; D008943:Mitral Valve; D011183:Postoperative Complications / Q000517:prevention & control; D011474:Prosthesis Design; D012307:Risk Factors; D013923:Thromboembolism / Q000517:prevention & control
chemical_list: D000925:Anticoagulants