title: Thromboembolism prophylaxis with dabigatran leads to lower perioperative blood loss than with dalteparin in primary knee arthroplasty.
abstract: BACKGROUND
  Low-molecular-weight heparins (LMWH) are commonly used in thrombosis prophylaxis after total knee arthroplasty. In contrast to LMWH, dabigatran etexilate is an oral and direct acting anticoagulant. The hypothesis of the present study was that blood loss occurring in total knee arthroplasty (TKA) is not greater after dabigatran etexilate than after dalteparin.
  
  
  METHODS
  All patients suffering from primary arthrosis of knee joint that had received a total knee arthroplasty were included in this retrospective case-control study. Two groups were formed (dalteparin versus dabigatran etexilate) and the perioperative blood loss was compared using the formula of Nadler (V = EBV × ln (Hct(0)/Hct(1)) [V = blood loss (l); EBV = blood volume (l); Hct(0) = preoperative haematocrit; Hct(1) = haematocrit on the first postoperative day].
  
  
  METHODS
  A total of 155 patients, 61 men and 94 women, were included. The calculated blood loss differed significantly between the two groups. The blood loss was on average 1.5 ± 0.58 l [0.32-2.9 l] in the dalteparin group, compared with 1.3 ± 0.63 l [0.29-4.31 l] in the dabigatran etexilate group (p < 0.01). None of the patients of both observed groups showed clinical signs of thrombosis or pulmonary artery embolism.
  
  
  RESULTS
  Dabigatran etexilate showed a lower perioperative blood loss than dalteparin by comparable safety of both drugs.
  
  
  CONCLUSIONS
  Whether the timing of administration or pharmacological factors were responsible for this cannot be explained by our study.
authors.affiliation: Department of Orthopaedics, Center for Musculoskeletal Surgery, Charité-University Medicine, Charitéplatz 1, 10117 Berlin, Germany. Doerte.Matziolis@Charite.de
authors.forename: Doerte
authors.initials: D
authors.lastname: Matziolis
authors.forename: Georg
authors.initials: G
authors.lastname: Matziolis
authors.forename: Carsten
authors.initials: C
authors.lastname: Perka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D058833:Antithrombin Proteins / Q000627:therapeutic use*; D019645:Arthroplasty, Replacement, Knee; D001562:Benzimidazoles / Q000627:therapeutic use*; D016063:Blood Loss, Surgical / Q000517:prevention & control*; D016022:Case-Control Studies; D000069604:Dabigatran; D017985:Dalteparin / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011725:Pyridines / Q000627:therapeutic use*; D012189:Retrospective Studies; D013923:Thromboembolism / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D058833:Antithrombin Proteins; D001562:Benzimidazoles; D011725:Pyridines; D000069604:Dabigatran; D017985:Dalteparin