title: Effects of standard unfractionated and low-molecular-weight heparins on platelets of patients undergoing total hip replacement surgery.
abstract: For prevention of venous thromboembolism in general and in orthopedic surgery, patients are treated prophylactically with standard unfractionated heparins (SH) or with low-molecular-weight heparins (LMWH). Patients (n = 22) undergoing total hip replacement surgery received either 5,000 IU SH (Heparin-Na) three times per day (n = 10 patients) or LMWH (Fraxiparin) once per day (n = 12 patients). Blood samples using CTAD (citrate, theophylline, adenine, dipyridamole) as anticoagulant were collected perioperatively after the first heparin administration, after the operation, and daily until day 4 postoperatively. After cooling at 4 degrees C blood samples were centrifuged, platelet-rich plasmas (PRPs) prepared, and after platelet counting PRPs were divided into platelet sediments (PS) and platelet-poor plasmas (PPP). Cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), serotonin, P-selectin, and laminin were analyzed in PPP and in PS after two freezing/thawing cycles. Platelet serotonin contents and serotonin release did not differ in either heparin group (SH and LMWH). In the LMWH group, 72 h postoperatively the intraplatelet cAMP was significantly (p < 0.01) higher. P-selectin values in PPP and platelet P-selectin release did not vary between the SH and the LMWH group; on the contrary, the platelet P-selectin content increased in the LMWH group 72 and 96 h postoperatively, while in the SH group this parameter showed a small decrease. The differences were significant (p < 0.05). The platelet-bound laminin underwent a slight change 48 and 72 h postoperatively in the LMWH group, but in the SH group the platelet-bound laminin increased permanently and significantly (p < 0.05; p < 0.01) until 72 h postoperatively, but 96 h postoperatively there was a small decline. In the SH group, 24-96 h postoperatively the platelet-bound laminin was significantly (p < 0.05; p < 0.005) augmented, compared with the LMWH group. The higher cAMP and P-selectin contents in the LMWH group suggest that platelets are less impaired by LMWH, and the augmented platelet-bound laminin in the SH group could express the platelet impairment evoked by standard unfractionated heparins.
authors.affiliation: Department of Surgery, Ruprecht-Karls University, Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Aulmann
authors.forename: S
authors.initials: S
authors.lastname: Kwasniki
authors.forename: B W
authors.initials: BW
authors.lastname: Böttiger
authors.forename: P J
authors.initials: PJ
authors.lastname: Meeder
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage*; D019644:Arthroplasty, Replacement, Hip; D004305:Dose-Response Relationship, Drug; D006493:Heparin / Q000008:administration & dosage*; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage*; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects*; D010979:Platelet Function Tests; D011183:Postoperative Complications / Q000097:blood / Q000517:prevention & control*; D012307:Risk Factors; D013924:Thrombophlebitis / Q000097:blood / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D006495:Heparin, Low-Molecular-Weight; D006493:Heparin