Novel oral anticoagulants for thromboprophylaxis after orthopaedic surgery

Guidelines for the prevention of venous thromboembolism in hospitalized patients with pelvi-acetabular trauma

BACKGROUND

Venous thromboembolism is a dreaded complication leading to increased morbidity and mortality in patients having pelvi-acetabular fractures.

OBJECTIVES

These evidence based guidelines aim to provide the decision making ability in the prevention of venous thromboembolism in patients with pelvi-acetabular trauma planned for operative or non operative treatment.

METHODS

The patients were subclassified into 5 categories. The PICO framework was used to devise research questions in each category. The systematic reviews were performed for each research question. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess outcomes of critical interest. The guideline panel consisting of expert members of different subspecialties, analyzed the evidence and made recommendations.

RESULTS

The guideline panel proposed 21 recommendations. There are five recommendations in category 1 to 3, two recommendations in category 4 and four recommendations in category 5.

CONCLUSION

In pelvi-acetabular fractures there is strong evidence to suggest that thromboprophylaxis should be given. It should be initiated as early as possible after control of hemorrhage. The chemical prophylaxis is the preferred mode and LMWH is the preferred agent of choice. The mechanical methods can be used as an adjunct. The routine prophylactic use of IVC filters is not recommended. However, the use of retrievable IVC filters in high risk patients with established VTE in preoperative period can be considered. The use of newer directly acting oral anticoagulants is gaining importance.

Risk of venous thromboembolism during rehabilitation of patients with spinal cord injury

Background

Patients with spinal cord injury (SCI) are at risk of thrombosis and bleeding. Data on the risks during rehabilitation are inconsistent, and thromboprophylactic strategies are heterogeneous. We aimed to evaluate the thrombotic risk and bleeding events of SCI patients during rehabilitation.

Methods

We retrospectively collected hospital record data of 263 consecutive SCI patients admitted at a rehabilitation clinic. 78 patients with acute venous thromboembolism (VTE) at the primary center, without acute trauma or lower extremity paresis, less than one month rehabilitation, or reasons for long-term therapeutic anticoagulation, were excluded. All patients received pharmacologic thromboprophylaxis throughout rehabilitation. Primary endpoint was objectively diagnosed VTE; secondary endpoint was bleeding.

Results

Of 185 patients, 162 (88%) were men; mean age was 47.8 years. 94 patients were tetraplegic, 91 paraplegic. During a mean (±SD) time of 5.1±2.1 months, VTE was diagnosed in 8 patients. After excluding five patients with VTE detected within 2 days after admission, the probability of developing VTE after 6 months of rehabilitation was 2% (95% CI 0–4.4%). Only high D-Dimer upon admission was associated with risk of VTE (adjusted HR 2.3, 95% CI 1.4–4.1). Of 24 bleedings, 14 (64%) occurred at the heparin injection site. Two patients had major bleeding and five had clinically relevant non major bleeding.

Conclusion

SCI patients are at risk of VTE and bleeding during rehabilitation. Strategies need to be developed to identify these patients in order to initiate adequate anticoagulation. Direct oral anticoagulants, which have a favourable risk-benefit profile and are convenient, should be explored.

Low-Molecular-Weight Heparin and the Relative Risk of Surgical Site Bleeding Complications: Results of a Systematic Review and Meta-Analysis of Randomized Controlled Trials of Venous Thromboprophylaxis in Patients After Total Joint Arthroplasty

BACKGROUND

Venous thromboembolism causes significant morbidity and mortality in patients after total joint arthroplasty. Although network meta-analyses have demonstrated a benefit of various thromboprophylactic agents, there remains a concern in the surgical community regarding the resulting wound complications. There is currently no systematic review of the surgical site bleeding complications of thromboprophylactic agents. The aim of this study was to systematically review the surgical site bleeding outcomes of venous thromboembolism prophylaxis in this population.

METHODS

A systematic review and meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Randomized controlled trials comparing more than one of low-molecular-weight heparin (LMWH), warfarin, rivaroxaban, apixaban, dabigatran, aspirin, or no pharmacologic treatment in patients after total hip or knee arthroplasty were selected for inclusion. Five meta-analyses were performed to compare LMWH with control, warfarin, apixaban, rivaroxaban, and dabigatran.

RESULTS

Forty-five randomized controlled trials of 56,730 patients were included. LMWH had a significantly increased relative risk of surgical site bleeding in comparison with control (relative risk, 2.32; 95% confidence interval, 1.40-3.85) and warfarin (1.54; 1.23-1.94). The relative risk of LMWH trended higher than apixaban (1.27; 1.00-1.63) and was similar to rivaroxaban (0.95; 0.74-1.23). Only 1 study reported the risk of surgical site bleeding in LMWH vs dabigatran (5.97; 2.08-17.11).

CONCLUSION

LMWH increased the risk of surgical site bleeding compared with control, warfarin. and dabigatran and trended toward an increased risk compared with apixaban. The risk of surgical site bleeding was similar with LMWH and rivaroxaban.

Unfractionated heparin and mechanical thromboprophylaxis in hip arthroplasty

OBJECTIVE:

To evaluate the efficacy and safety of unfractionated heparin associated with mechanical prophylaxis as a method for preventing venous thromboembolism in hip arthroplasty.

METHOD:

We retrospectively reviewed the records of 181 hip arthroplasties out of 216 consecutive cases performed over a period of 39 months in our hospital. We excluded 35 cases due to non-adherence to the standardized method of thromboprophylaxis or loss to follow-up. All arthroplasties evaluated completed one-year follow-up after surgery with five consultations at predefined periods. Efficacy of the proposed method was evaluated by the occurrence of symptomatic venous thromboembolism confirmed by specific tests and safety was determined by the lack of occurrence of major bleeding according to criteria established by the International Society on Thrombosis and Haemostasis.

RESULTS:

There were four cases of symptomatic venous thromboembolism (2.2%), with three cases of deep vein thrombosis (1.65%) and one case of pulmonary embolism (0.55%). We found one case of severe bleeding (0.55%).

CONCLUSION:

Unfractionated heparin associated with mechanical prophylaxis proved to be an effective and safe method for preventing venous thromboembolism in patients undergoing hip arthroplasty, presenting rates of thromboembolic complications and major bleeding within the range reported with other methods currently used of thromboprophylaxis. Level of Evidence IV, Case Series

New oral pharmacotherapeutic agents for venous thromboprophylaxis after total hip arthroplasty

Patients undergoing total hip arthroplasty (THA) are at high risk for developing venous thromboembolism and, therefore, require short term prophylaxis with antithrombotic agents. Recently, target specific oral anticoagulants (TSOA) including the direct thrombin inhibitor, dabigatran, and the factor Xa inhibitors rivaroxaban, apixaban, and edoxaban have been approved for THA thrombopropylaxis in various countries. The TSOAs provide a rapid acting, oral alternative to parenteral agents including low-molecular weight heparins (LMWH) and fondaparinux; and compared to warfarin, they do not require routine laboratory monitoring and possess much fewer drug-drug interactions. Based on phase III clinical studies, TSOAs have established themselves as an effective and safe option for thromboprophylaxis after THA compared to LMWH, particularly enoxaparin, but require additional evaluation in specific populations such as the renally impaired or elderly. The ability to monitor and reverse these TSOAs in the case of bleeding complications or suspected sub- or supra-therapeutic anticoagulation is of importance, but remains investigational. This review will focus on the drug-specific characteristics, efficacy, safety, and economic impact of the TSOAs for thromboprophylaxis following THA, as well as the aspects of therapeutic monitoring and anticoagulation reversal in the event of bleeding complications or a need for urgent reversal.

Perioperative management of patients on new oral anticoagulants

Background

New oral anticoagulants (NOACs) offer an alternative to warfarin for preventing stroke in patients with atrial fibrillation. NOACs are expected to replace warfarin and other vitamin K antagonists for most of their indications in the future. Knowledge of the use of NOACs in the perioperative period is important for optimal care.

Methods

Studies that reported on the use of NOACs were identified, focusing on evidence-based guidance relating to the perioperative period. PubMed was searched for relevant articles published between January 2000 and January 2014.

Results

The anticipated expanded clinical use of NOACs such as rivaroxaban (Xarelto™), apixaban (Eliquis™) and dabigatran (Pradaxa™) has the potential to simplify perioperative anticoagulant management because of fewer drug–drug interactions, rapid onset of action, predictable pharmacokinetics and relatively short half-lives. However, coagulation status cannot be monitored by international normalized ratio and no antidotes are currently available. In elective surgery, it is important to discontinue the use of NOACs, with special consideration of renal function as route of elimination. Guidelines for the management of bleeding complications in patients on NOACs are provided, and may be considered for trauma and emergency surgery. Haemodialysis could be considered for bleeding with use of dabigatran. Better options for reversal of the effects of NOACs when bleeding occurs may follow with novel drugs.

Conclusion

Management of NOACs in elective and emergency conditions requires knowledge of time of last intake of drug, current renal function and the planned procedure in order to assess the overall risk of bleeding. Currently no antidote exists to reverse the effects of these drugs.