Use of the chromogenic factor X assay to predict the international normalized ratio in patients transitioning from argatroban to warfarin

被引:28
作者
Arpino, PA
Demirjian, Z
Van Cott, EM
机构
[1] Harvard Univ, Dept Pharm, Massachusetts Gen Hosp, Sch Med, Boston, MA 02114 USA
[2] Harvard Univ, Dept Hematol, Massachusetts Gen Hosp, Sch Med, Boston, MA 02114 USA
[3] Harvard Univ, Dept Pathol, Massachusetts Gen Hosp, Sch Med, Boston, MA 02114 USA
来源
PHARMACOTHERAPY | 2005年 / 25卷 / 02期
关键词
chromogenic factor X; international normalized ratio; INR; warfarin; argatroban;
D O I
10.1592/phco.25.2.157.56950
中图分类号
R9 [药学];
学科分类号
1007 ;
摘要
Study Objective. To determine the clinical utility of the chromogenic factor X level for conversion from argatroban to warfarin in hospitalized patients. Design. Prospective observational study. Patients. Sixty-two hospitalized patients with indications for anticoagulation in whom the chromogenic factor X assay was used for conversion from argatroban to warfarin. Setting. University-affiliated hospital. Intervention. From December 2003-May 2004, data for all patients in whom the chromogenic factor X assay was used for conversion from argatroban to warfarin were screened for inclusion. When the chromogenic factor X level was satisfactory, the clinician discontinued the argatroban and a confirmatory international normalized ratio (INR) was obtained. Measurements and Main Results. To determine the ability of the chromogenic factor X level to predict the INR free of argatroban influence, we calculated the sensitivity and specificity by using a cutoff chromogenic factor X level of 45% or less, or greater than 45%, which corresponded to an INR of 2 or greater, or less than 2, respectively. We constructed a receiver operating characteristic curve to illustrate various cutoff levels of chromogenic factor X. Of 146 patients screened, 62 had data that met criteria for analysis. An average of 6 +/- 3 doses of warfarin were administered before the confirmatory coagulation studies were obtained. The average time from the chromogenic factor X measurement to obtainment of confirmatory coagulation studies was 9 +/- 4 hours. Use of a chromogenic factor X level of 45% or less to predict an INR of 2 or greater absent of argatroban influence had a sensitivity of 93%, a specificity of 78%, and an accuracy of 89%. The area under the receiver operating characteristic curve was 0.91 (95% confidence interval 0.81-0.99, p<0.0001). Conclusion. The chromogenic factor X level is an accurate alternative when converting hospitalized patients from argatroban to warfarin. A chromogenic factor X level of 45% or less is a reliable predictor that the INR will be therapeutic when argatroban therapy is discontinued.
引用
收藏
页码:157 / 164
页数:8
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