Venous thrombosis prophylaxis in haemophilics undergoing major orthopaedic surgery: a survey of haemophilia treatment centres

Patients undergoing major orthopaedic surgery, such as hip or knee arthroplasty, are at particularly high risk for thrombotic events because of the nature of the surgery and of postoperative immobilization, and routine pharmacological thromboprophylaxis has been the standard of care for more than 15 years [1]. Hip and knee replacement surgery for treatment of major haemophilic arthropathy and joint deformities is often required in the care of patients with severe haemophilia. Patients with haemophilia are often considered to be at exceptionally low risk for postoperative thromboembolic complications by virtue of their bleeding disorder. However, peri-operative correction of the haemostatic defect with clotting factor concentrates presumably puts these patients at risk for developing postoperative venous thromboembolism (VTE) that is equal to or higher than that of the general population [if factor VIII (FVIII) and FIX levels >1.5 IU mL−1] [2,3]. Despite correction of the haemostatic defect, thrombotic risk is generally felt to be not high enough to warrant pharmacological thromboprophylaxis. In the presence of additional risk factors, such as an inherited thrombophilia, the risk of VTE is likely to be further increased [2,4]. Co-inheritance of the Leiden or prothrombin 20210 gene mutations has also been suggested to lead to an attenuated haemophilia phenotype, supporting the notion of increased postoperative VTE risk in this population with normalized factor VIII or FIX levels. Given the ageing demographics and increasing joint disease associated with obesity in the haemophilia population [5], the question of thrombotic risk associated with major joint replacement surgery is likely to continue to be a highly relevant issue. As management of VTE in haemophilia patients poses unique challenges and incurs greater potential for increased morbidity, optimizing preventive strategies in this population is critical. Currently, no evidence-based guidelines or consensus statements from haemophilia experts, networks or advocacy groups exist. Furthermore, we are not aware of any prospective clinical trials addressing this issue. Thus, current practice in this setting will likely vary and remain controversial. To delineate current attitudes and practices on peri-operative thromboprophylaxis in haemophilia patients undergoing orthopaedic surgery, a brief e-mail survey consisting of four key questions was sent to approximately 140 Federally funded Hemophilia Treatment Centers in the United States in 2005. A total of 60 responses were received and are summarized below. Question 1: Do you believe that patients with haemophilia who undergo hip/knee arthroplasty and are on factor replacement therapy are at high enough risk for deep vein thrombosis to warrant some type of thromboprophylaxis? For this, 67% responded ‘yes’, 25% responded ‘no’ and 8% responded that this question was not applicable, given that they predominantly managed paediatric patients who rarely undergo joint replacement. Question 2: Do you currently provide thromboprophylaxis to all haemophilia patients on factor replacement therapy undergoing hip or knee arthroplasty? Of the 67% in support of prophylaxis, 55% answered ‘yes’ and 45% responded ‘no’. Thus, among Hemophilia Treatment Centers, there clearly exists a clinical equipoise with respect to the use of thromboprophylaxis in this setting. Question 3: Do you currently provide thromboprophylaxis to selected haemophilia patients on factor replacement therapy undergoing hip or knee arthroplasty (e.g. only if their respective FVIII or FIX levels are above a certain cut–off, e.g. >100% activity?) Of the 45% of providers who do not provide thromboprophylaxis to all patients, 78% provide prophylaxis to selected patients, e.g. only if clotting factor levels are above a certain point and 22% provide no thromboprophylaxis. The final question addressed the precise modality of thromboprophylaxis used. Of those providing thromboprophylaxis, 32% reported using compression stockings, 35% as using Sequential Compression Devices, 24% reported using low molecular weight heparin, 1% fondaparinux, 3% unfractionated heparin, 4% warfarin and 1% aspirin. Notably, recent ACCP recommendations guide against the use of aspirin alone as thromboprophylaxis in any patient group. Until the prevalence of deep vein thrombosis in haemophilic patients following major surgery is known, the risk benefit of pharmacological prophylaxis cannot be confidently predicted. It is reasonable to assume that the risks of both thrombosis and bleeding may vary with the intensity and duration of factor replacement therapy used at the time of surgery. It is unlikely that a randomized prospective clinical trial will ever be accomplished in this population, but determination of the rate of asymptomatic DVT by objective diagnostic screening does deserve further study. These rates in the non-coagulopathic patient population have been well-studied. Data from such a study in haemophilia could serve as the basis for standard guidelines or formal recommendations regarding optimal preventive strategies for thromboprophylaxis for patients in this setting. L. Boggio has received funds 5 years ago for a clinical trial with Idraparinux in patients with VTE. The rest of the authors have stated that they had no interests which might be perceived as posing a conflict or bias.