Thromboelastography as a perioperative measure of anticoagulation resulting from low molecular weight heparin: a comparison with anti-Xa concentrations.

Published

Journal Article

UNLABELLED: Low molecular weight heparin (LMWH) is commonly used to prevent postoperative thromboembolism. Currently, there is no convenient test to measure the degree of anticoagulation from LMWH. This prospective study examines the relationship of thromboelastography and serum anti-Xa concentration in patients treated with enoxaparin. Twenty-four adult patients scheduled for orthopedic surgery using epidural anesthesia were enrolled. Epidural catheters were removed the morning after surgery before the commencement of subcutaneous enoxaparin 30 mg twice daily. Venous blood samples were obtained at 1) the induction of anesthesia (baseline), 2) immediately before the third dose of enoxaparin postoperatively (Day 2-trough), 3) 4 h after the third dose postoperatively (Day 2-peak), and 4) immediately before the fifth dose postoperatively (Day 3-trough). Whole blood samples were obtained for thromboelastography, activated clotting time, and anti-Xa level analyses at each of the four time intervals. At the four sample intervals, the r time (mean +/- SEM). (20 +/- 1, 25 +/- 2, 51 +/- 6, 31 +/- 3 mm) and the k time (9 +/- 0. 7, 12 +/- 1, 27 +/- 5, 14 +/- 2 mm) of the thromboelastograph were significantly correlated with the expected peak and trough levels of LMWH and serum anti-Xa levels (P: < 0.05). At the Day 3-trough, thromboelastograph r times exceeded the normal range in 6 of 25 patients (25%). Prolongation of r time and k time on postoperative Day 3 may indicate an exaggerated response to LMWH. Thromboelastography is a test that could potentially correlate with the degree of anticoagulation produced by low molecular weight heparin. IMPLICATIONS: Thromboelastography is a test that could potentially correlate with the degree of anticoagulation produced by low molecular weight heparin. The r time from the thromboelastogram correlates with serum anti-Xa concentration.

Full Text

Duke Authors

Cited Authors

  • Klein, SM; Slaughter, TF; Vail, PT; Ginsberg, B; El-Moalem, HE; Alexander, R; D'Ercole, F; Greengrass, RA; Perumal, TT; Welsby, I; Gan, TJ

Published Date

  • November 2000

Published In

Volume / Issue

  • 91 / 5

Start / End Page

  • 1091 - 1095

PubMed ID

  • 11049889

Pubmed Central ID

  • 11049889

International Standard Serial Number (ISSN)

  • 0003-2999

Digital Object Identifier (DOI)

  • 10.1097/00000539-200011000-00009

Language

  • eng

Conference Location

  • United States