title: Surgery, venous thrombosis and anti-Xa.
abstract: Deep venous thrombosis is a common and unpredictable complication of surgery. In this study it is proposed that patients who develop this complication may be predicted by a low preoperative level of a naturally occurring inhibitor of coagulation, anti-Xa. Two groups of patients were investigated. Women taking the oral contraceptive pill had lower preoperative anti-Xa levels than their non-pill controls (P less than 0.01) and in addition had a significantly higher incidence of deep venous thrombosis (DVT) following emergency surgery (P less than 0.05). In 90 patients undergoing total hip replacement, the mean preoperative anti-Xa level of those patients who developed DVT was significantly lower than those who did not (P less than 0.001). Ninety-four per cent of patients with a preoperative anti-Xa level of less than 80 per cent developed DVT. The effect of low dose heparin on anti-Xa was studied. The results suggest a mechanism for the cause of postoperative thrombosis which also permits selection of individual patients who will develop this complication.
mesh_terms: D000293:Adolescent; D000328:Adult; D000510:Alpha-Globulins / Q000032:analysis*; D000990:Antithrombin III / Q000032:analysis*; D001777:Blood Coagulation / Q000187:drug effects; D003276:Contraceptives, Oral / Q000009:adverse effects* / Q000494:pharmacology; D005260:Female; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D011183:Postoperative Complications; D013924:Thrombophlebitis / Q000209:etiology*; D013997:Time Factors
chemical_list: D000510:Alpha-Globulins; D003276:Contraceptives, Oral; D000990:Antithrombin III; D006493:Heparin