title: Validation of a bedside activated clotting time test (Hemochron Jr II Signature) with low dose heparin therapy.
abstract: The purpose of this study was to validate a device designed to measure activated clotting time in low-range heparin plasma concentrations (ACT-LR) prospectively during the post-operative period of vascular surgery. Measurement of ACT-LR and activated partial thromboplastin time (APTT) were performed before heparinisation (T0) and at the end of surgery (T1). ACT-LR(T1) and DeltaACT-LR (defined as ACT-LR(T1) - ACT-LR(T0)) were evaluated as diagnostic tests for excessive anticoagulation, defined by APTT more than twice the laboratory's normal, by Bland-Altman method and receiver operating characteristic (ROC) curves. In 103 patients, mean (SD) ACT-LR was 137 (33) s at T0 and 176 (39) s at T1. Bland-Altman graph did not show a good agreement between APTT and ACT-LR. Areas under ROC curves were 0.82 (95% CI: 0.75-0.89) and 0.87 (95% CI: 0.80-0.93) for ACT-LR(T1) and DeltaACT-LR, respectively. Using a threshold of 32 s for DeltaACT-LR, test sensitivity was 87% (95% CI: 81-93%), specificity was 85% (95% CI: 78-92%), positive predictive value was 90% (95% CI: 84-96%) and negative predictive value was 81% (95% CI: 73-86%). While DeltaACT-LR may have some potential in evaluating excessive anticoagulation in vascular surgery, the poor correlation between ACT-LR and APTT does not support its routine use.
authors.affiliation: Service d'Anesthésie-Réanimation 1, Centre-Hospitalo-Universitaire de Bordeaux, 33076 Bordeaux Cedex, France.
authors.forename: L
authors.initials: L
authors.lastname: Racioppi
authors.forename: A
authors.initials: A
authors.lastname: Quinart
authors.forename: M
authors.initials: M
authors.lastname: Biais
authors.forename: K
authors.initials: K
authors.lastname: Nouette-Gaulain
authors.forename: P
authors.initials: P
authors.lastname: Revel
authors.forename: F
authors.initials: F
authors.lastname: Sztark