title: Protein C, S and antithrombin III levels in patients with acute mechanical valve thrombosis.
abstract: BACKGROUND
  Mechanical prosthetic heart valve thrombosis is a serious complication with an incidence of 1-6%. The reduction in active vitamin-K dependent protein C and S levels caused by warfarin treatment also results in a prothrombotic state. This study was conducted to investigate the connection between protein C (PC), protein S (PS), antithrombin III (ATIII) deficiency and prosthetic mechanical valve thrombosis.
  
  
  METHODS
  Twenty-nine of the 283 patients who underwent valve replacement with St. Jude medical prosthesis had mechanical valve thrombosis (group 2). The rest were considered as group 1. Twelve of the 29 patients (41.4%) had isolated aortic valve replacement, 12 had isolated mitral valve replacement (41.4%) and 5 patients had double valve replacement (17.2%). Most of the patients had rheumatic valve disease at their 1st operation. The mean time of occurrence for mechanical valve occlusion was 4.1+/-1.0 years following surgery.
  
  
  RESULTS
  The values of PC, PS and ATIII were obtained when the mechanical valves stuck or at routine follow-up. PC, PS and ATIII levels were significantly lower in the mechanical valve thrombosis group. PC levels were 75.4+/-37.6% and 49.9+/-32.2% in group 1 and 2, respectively (p=0.001). PC, PS and ATIII values were mostly lower in the 2nd group but this difference only became significant after at least 2 years of warfarin usage.
  
  
  CONCLUSIONS
  Natural anticoagulant levels can be low during the use of warfarin. In which case the dose can be increased in order to hold the international normalized ratio (INR) at 3-3.5. However, more frequent follow-up is required and patients should be investigated for hypercoagulation states or deficiency in anticoagulant proteins. Patients referred to hospital with any mechanical valve thrombosis or recurrent thromboembolism should be evaluated for hypercoagulant proteins.
authors.affiliation: Department of Cardiovascular Surgery, Türkiye Yüksek Ihtisas Hospital, Ankara, Turkey. uluss@yahoo.com
authors.forename: U
authors.initials: U
authors.lastname: Tütün
authors.forename: A T
authors.initials: AT
authors.lastname: Ulus
authors.forename: A
authors.initials: A
authors.lastname: Aksöyek
authors.forename: S
authors.initials: S
authors.lastname: Kaplan
authors.forename: S
authors.initials: S
authors.lastname: Ayaz
authors.forename: S
authors.initials: S
authors.lastname: Yilmaz
authors.forename: L
authors.initials: L
authors.lastname: Birincioglu
authors.forename: S F
authors.initials: SF
authors.lastname: Katircioglu
mesh_terms: D000328:Adult; D000990:Antithrombin III / Q000378:metabolism*; D001022:Aortic Valve Insufficiency / Q000601:surgery; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008944:Mitral Valve Insufficiency / Q000601:surgery; D011486:Protein C / Q000378:metabolism*; D017293:Protein S / Q000378:metabolism*; D013927:Thrombosis / Q000209:etiology*
chemical_list: D011486:Protein C; D017293:Protein S; D000990:Antithrombin III