title: Effect of warfarin on calcification of spontaneously degenerated porcine bioprosthetic valves.
abstract: Synthesis of a calcium-binding amino acid, gamma-carboxyglutamic acid, is a vitamin K-dependent enzymatic process. Warfarin inhibits gamma-carboxyglutamic acid synthesis and, therefore, might diminish the calcification of porcine bioprosthetic valves. To evaluate this, we studied 40 porcine bioprosthetic valves removed because of spontaneous degeneration; 17 patients were treated with warfarin (prothrombin time greater than or equal to 1.5 control) and 23 were untreated. Gross visualization of calcification corresponded closely to x-ray visualization of calcification in explanted valves. No grossly visible calcification or only a single localized nodule was shown in 11 of 17 valves (65%) in treated patients and in only five of 23 valves (22%) in untreated patients (p less than 0.02). Histologic examination showed no calcium or only fine specks of calcium in nine of 13 valves (69%) among warfarin-treated patients and three of 19 valves (16%) from untreated patients. Warfarin, therefore, administered in usual clinical doses, appeared to diminish calcification in spontaneously degenerated porcine bioprosthetic valves.
authors.forename: P D
authors.initials: PD
authors.lastname: Stein
authors.forename: J M
authors.initials: JM
authors.lastname: Riddle
authors.forename: S R
authors.initials: SR
authors.lastname: Kemp
authors.forename: M W
authors.initials: MW
authors.lastname: Lee
authors.forename: J W
authors.initials: JW
authors.lastname: Lewis
authors.forename: D J
authors.initials: DJ
authors.lastname: Magilligan
mesh_terms: D015055:1-Carboxyglutamic Acid / Q000096:biosynthesis; D000328:Adult; D000368:Aged; D001021:Aortic Valve / Q000601:surgery; D001705:Bioprosthesis; D002114:Calcinosis / Q000378:metabolism / Q000473:pathology* / Q000517:prevention & control; D019735:Carbon-Carbon Ligases; D005260:Female; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D006350:Heart Valve Prosthesis; D006801:Humans; D008025:Ligases / Q000502:physiology; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery; D014859:Warfarin / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D005971:Glutamates; D018698:Glutamic Acid; D015055:1-Carboxyglutamic Acid; D014859:Warfarin; D008025:Ligases; D019735:Carbon-Carbon Ligases; C020660:glutamyl carboxylase