Relation between peri-operative antithrombin activity and deep vein thrombosis after elective hip replacement surgery.
BACKGROUND
The purpose of the study was to evaluate whether the postoperative depletion or the preoperative antithrombin (AT) activity is related to the occurrence of deep vein thrombosis (DVT) in patients receiving low-molecular-weight heparin for DVT prevention after elective hip replacement surgery.


METHODS
In 93 patients AT-activity and standard laboratory parameter were determined on the preoperative day and daily for one week after operation. Furthermore, a color-coded compression sonography was performed before and 8-10 days after surgery. The amount of blood loss and blood transfusions was evaluated. Patients were divided into two groups in respect to the occurrence of a postoperative DVT.


RESULTS
The overall incidence of DVT was 8.6% (n = 8). Patients with DVT had a significantly lower preoperative AT-activity (80.6 +/- 3.31%) compared to those without DVT (98.1 +/- 1.12%, p < 0.001), however, without being predictive for DVT (positive predictive value 0.71). There was no association between postoperative fall of AT, the lowest postoperative AT activity, blood loss or blood substitution and DVT.


CONCLUSIONS
It has to be expected that a small fraction of patients for elective hip surgery present with AT-activity levels possibly being insufficient for a therapeutic effect of low-molecular-weight heparin even preoperatively. Those patients are subject to a significant higher risk of DVT postoperatively.
Urbach
D
D
Department of Orthopedics, Otto-von-Guericke University, Magdeburg, Germany. dietmar.urbach@medizin.uni-magdeburg.de
Matzen
K A
KA
Heitmann
D
D
Neumann
H W
HW
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000991:Antithrombins / Q000378:metabolism*; D019644:Arthroplasty, Replacement, Hip; D016063:Blood Loss, Surgical / Q000503:physiopathology; D001803:Blood Transfusion; D005260:Female; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood* / Q000517:prevention & control; D012307:Risk Factors; D020246:Venous Thrombosis / Q000097:blood* / Q000517:prevention & control
D000991:Antithrombins; D006495:Heparin, Low-Molecular-Weight