title: [Optimum anticoagulation control after bileaflet mechanical valve replacement: a prospective multi-institutional study].
abstract: This study was undertaken to assess optimum anticoagulation control after bileaflet mechanical valve replacement by using the international normalized ratio of prothrombin time (PT-INR). From January to December 1995, 261 patients (pts) underwent mechanical valve replacement in the aortic (n = 95), mitral (n = 126), aortomitral (n = 39) or isolated tricuspid (n = 1) valve position in 8 medical centers in Tokyo, Japan. The St. Jude Medical valves were implanted in 184 pts and the Carbomedics valves in 77. There were 17 valve-related events as follows: 11 thromboembolic events (3.62%/pt-yr) including 10 transient ischemic attacks. 5 non-fatal bleeding events (1.65%/pt-yr), 2 reoperations (0.66%/pt-yr). At 18 postoperative months, free rates from all deaths (actuarial survival) thromboembolism, reoperation and all valve-related events were 95.3%, 95.7%, 98.7% and 88.9%, respectively. Under anticoagulant therapy, thrombin-antithrombin III complex and D-dimmer remained in high levels at 1 month after operation, and both values decreased to the control level at 6 months. In patients with thromboembolic events, PT-INR tended to be less than 2.0. The patients with bleeding events showed some increase of PT-INP or received anti-platelet agents. The 5 to 95 percentile of PT-INR at 6 months was 1.2 to 3.0 in the patients without valve-related events. These results suggested that optimum range of PT-INR might be between 1.2 and 3.0 after bileaflet mechanical valve replacement in patients without high risk of thromboembolism and between 2.0 and 3.0 in patients with the high risk.
authors.affiliation: Tokyo Area Anticoagulation Study (TAS) Group, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kitamura
authors.forename: H
authors.initials: H
authors.lastname: Koyanagi
authors.forename: S
authors.initials: S
authors.lastname: Kawada
authors.forename: Y
authors.initials: Y
authors.lastname: Hosoda
authors.forename: H
authors.initials: H
authors.lastname: Kurosawa
authors.forename: Y
authors.initials: Y
authors.lastname: Takeuchi
authors.forename: M
authors.initials: M
authors.lastname: Kawase
authors.forename: Y
authors.initials: Y
authors.lastname: Wanibuchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage*; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D011183:Postoperative Complications / Q000517:prevention & control*; D011446:Prospective Studies; D011517:Prothrombin Time; D013923:Thromboembolism / Q000517:prevention & control*; D014859:Warfarin / Q000008:administration & dosage*
chemical_list: D000925:Anticoagulants; D014859:Warfarin