title: Dose relation in the prevention of proximal vein thrombosis with a low molecular weight heparin (tinzaparin) in elective hip arthroplasty.
abstract: This is a review of a double-blind, prospective study comparing the thromboprophylactic efficacy and safety of two different prophylactic regimens of a low molecular weight heparin (tinzaparin) in 250 consecutive patients (aged < or 18) undergoing primary elective hip arthroplasty. Regimen 1: 75 U anti-Xa/kg BW (actual range 63 to 91) once daily started 12 hours before operation; and regimen 2: 50 U anti-Xa/kg BW (actual range 41 to 71) once daily started 2 hours before operation. Both regimens were administered in a weight-adjusted fashion and were continued for 7 days after operation or until full mobilization. Efficacy was evaluated by occurrence of postoperative deep vein thrombosis (DVT) diagnosed by bilateral ascending phlebography on day 7 +/- 2 after operation, and the venograms were evaluated in an assessor blind fashion by a panel of three expert radiologists. Safety was evaluated by the amount of blood lost and transfusion requirements during and after the operation; all bleeding complications, reoperations, adverse events and deaths were observed during the study. A 3-month follow-up on survival and occurrence of thromboembolism was performed on all randomized patients. The result was a significantly better protective effect against proximal DVT by regimen 1 compared with regimen 2. This was achieved with improved safety in terms of a significantly decreased need for blood transfusions during operation and fewer wound complications in the postoperative period in favor of regimen 1. Therefore, tinzaparin administered in a dosage of 75 U anti-Xa/kg BW 12 hours before surgery is significantly more protective against proximal DVT and safer than the standard regimen of 50 U anti-Xa/kg BW started 2 hours before surgery in patients undergoing primary elective hip arthroplasty.
authors.affiliation: Department of Orthopaedics, Aalborg Hospital, Denmark.
authors.forename: M R
authors.initials: MR
authors.lastname: Lassen
authors.forename: L C
authors.initials: LC
authors.lastname: Borris
authors.forename: H P
authors.initials: HP
authors.lastname: Jensen
authors.forename: K A
authors.initials: KA
authors.lastname: Poulsen
authors.forename: P
authors.initials: P
authors.lastname: Ejstrud
authors.forename: B S
authors.initials: BS
authors.lastname: Andersen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods* / Q000592:standards; D001803:Blood Transfusion; D004311:Double-Blind Method; D017558:Elective Surgical Procedures / Q000009:adverse effects / Q000592:standards; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006470:Hemorrhage / Q000209:etiology; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010690:Phlebography; D010976:Platelet Count; D011446:Prospective Studies; D015996:Survival Rate; D013921:Thrombocytopenia / Q000209:etiology; D000078222:Tinzaparin; D020246:Venous Thrombosis / Q000209:etiology* / Q000628:therapy*
chemical_list: D005343:Fibrinolytic Agents; D006495:Heparin, Low-Molecular-Weight; D000078222:Tinzaparin