Clinical significance of Thrombotest and PT-INR in monitoring the oral anticoagulant therapy

Uetsuka, Yoshio; Hosoda, Saichi; Aosaki, Masahiko; Iwade, Kazunori; Koyanagi, Hitoshi; Ohki, Katsuyoshi; Hokari, Taeko; Inoue, Miyuki; Akiyama, Etsuko; Kitada, Masukazu

doi:10.2491/jjsth.3.123

Cited by 7 publications

(4 citation statements)

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“…In Japan, the therapeutic range of the PT‐INR for patients with mechanical heart valves is set at 1.6 to 2.8, or 2.1 to 2.8 ( 1, 2). However, this range is somewhat lower than that employed in the U.S.A. and European countries.…”

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confidence: 99%

“…However, the thrombotest has recently been replaced by the prothrombin time international normalized ratio (PT‐INR), which is an international standard for monitoring anticoagulant therapy. Currently, the therapeutic range of the PT‐INR for Japanese patients with mechanical heart valves on anticoagulants is set at 1.6 to 2.8 ( 1). However, it is not clear whether this therapeutic range is optimum.…”

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confidence: 99%

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Anticoagulation After Valve Replacement: A Multicenter Retrospective Study

et al. 1999

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Anticoagulant therapy after cardiac valve replacement was evaluated retrospectively in 1,200 patients attending 8 cardiac surgery clinics in the Tokyo area as part of the Tokyo Area Study on Anticoagulation After Cardiac Valve Replacement Using PT-INR (TAS). A prospective trial is also in progress and will be reported later. The prothrombin time international normalized ratio (PT-INR) was determined at the time of thromboembolic and bleeding complications in 1,200 patients. During the 5 year study period, thromboembolisms occurred in 21 patients, and bleeding complications occurred in 15 patients. In 71% of patients with thromboembolism and 47% of those with bleeding complications, the PT-INR was within the range of 1.6 to 2.8, which is the accepted therapeutic range in Japan. Therefore, the correct PT-INR therapeutic range for Japanese patients with mechanical heart valves needs to be reexamined, and data from the prospective TAS trial that is currently underway will be used for this purpose.

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Anticoagulation After Valve Replacement: A Multicenter Retrospective Study

et al. 1999

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“…Therefore, the possibility of pannus that was formed from organizing thrombus may be expected in our patients. In Japan, however, the intensity of INR ranging from 1.6 to 2.8 is considered to be adequate for preventing thromboembolic and bleeding complications related to mechanical prosthetic valves [12][13][14]. The intensity of our anticoagulant therapy corresponds with this range of INR.…”

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confidence: 99%

Obstruction of St Jude Medical Valves in the Aortic Position: A Consideration for Pathogenic Mechanism of Prosthetic Valve Obstruction

Aoyagi

Nishimi

Tayama

et al. 2002

Cardiovascular Surgery

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Between 1995 and 2000, 8 patients with St. Jude Medical (SJM) valves in the aortic position required 9 redo valve replacement for prosthetic valve obstruction. Obstruction of the prosthetic valve was diagnosed by simultaneous echocardiography and cineradiography, and process of restricted leaflet movement that progressed to hemodynamic impairment was observed by serial studies in three recent patients. An oral anticoagulation was considered to be adequate in all patients except one patient who had withdrawal of warfrain. Pannus was the sole cause of valve obstruction in seven events in 6 patients, and both thrombus and pannus in 2 patients. Pannus overgrowth was found on the inflow aspect of the SJM valve, and involved the ends of the straight edge of the leaflets over pivot guards. These results suggest that pannus might play the primary role in development of obstruction of aortic SJM valves in patients on adequate oral anticoagulation.

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“…Their postoperative anticoagulant level was maintained at a prothrombin time ratio (international normalized ratio) of 1.6–2.1 in relation to the control value, or 10% to 20% of the thrombotest level using warfarin and an antiplatelet agent (dypiridamole 300 mg/day). Although this anticoagulant level is lower than the recommended level in Europe and North America, it is considered optimal for Japanese patients (4–6). We generally check the mechanical prosthesis function by routine echocardiography.…”

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confidence: 99%