Benefit-to-harm ratio of thromboprophylaxis for patients undergoing major orthopaedic surgery

Investigation into the Cost-Effectiveness of Extended Posttraumatic Thromboprophylaxis

BACKGROUND

Severely injured patients are at particularly high risk for venous thromboembolism (VTE). Although thromboprophylaxis (PPX) is employed during the inpatient period, patients may continue to be at high risk after discharge. Comparative evidence from surgical subspecialities (eg oncology) reveals benefits of postdischarge (ie extended) PPX. We hypothesized that an extended, postinjury oral thromboprophylaxis regimen would be cost-effective.

STUDY DESIGN

A cost-utility model compared no PPX with a 30-day course of apixaban, dabigatran, enoxaparin, fondaparinux, or rivaroxaban in trauma patients. Immediate events including deep venous thrombosis, pulmonary embolus, or bleeding within 30 days of injury were modeled in a decision tree with patients entering a Markov process to account for sequelae of VTE, including postthrombotic syndrome and chronic thromboembolic pulmonary hypertension. Effectiveness was measured in quality-adjusted life years. One-way and probabilistic sensitivity analyses were performed to identify conditions under which the preferred PPX strategy changed.

RESULTS

Rivaroxaban was the dominant strategy (ie less costly and more effective) compared with no PPX or alternative regimens, delivering 30.21 quality-adjusted life years for $404,546.38. One-way sensitivity analyses demonstrated robust preference for rivaroxaban. When examining only patients with moderate-high or high VTE Risk Assessment Profile scores, rivaroxaban remained the preferred strategy. Probabilistic sensitivity analysis demonstrated a preference for rivaroxaban in 100% of cases at a standard willingness-to-pay threshold of $100,000/quality-adjusted life year.

CONCLUSIONS

A 30-day course of rivaroxaban is a cost-effective extended thromboprophylaxis strategy in trauma patients in this theoretical study. Prospective studies of postdischarge thromboprophylaxis to prevent postinjury VTE are warranted.

Can thrombus age guide thrombolytic therapy?

Venous thrombosis (VT) is a common yet complex clinical condition that has shown minimal alteration in clinical management for decades. It is well known that thrombus evolves structurally over time, with complex changes resulting from the interplay between coagulation factors, cytokines, leukocytes and a myriad of other factors. Our current treatment options are most effective in the acute thrombus, which is composed predominantly of a loose mesh of fibrin and red blood cells (RBCs), making current anticoagulation therapies and thrombolytics quite effective in treatment. Later stages of thrombus are more cellular containing leukocytes, and develop a fibrotic collagenous framework that is more resistant to our current treatments. Understanding the biology of an evolving thrombus will allow us to tailor our treatment and optimize outcomes, as well as focus on novel therapies for the treatment of chronic thrombus. Given the morbidity and mortality of both post thrombotic syndrome (PTS) in patients with deep VT, as well as chronic thromboembolic pulmonary hypertension (CTEPH) in patients with pulmonary embolism (PE), new and innovative therapies must continue to be explored to help prevent these potentially devastating conditions.

Sleep apnea and venous thromboembolism. A systematic review

Recent evidence suggests that obstructive sleep apnea is a significant and independent risk factor for a number of cardiovascular disorders. Since the association between obstructive sleep apnea and cardiovascular disease is mediated by endothelial dysfunction, hypercoagulability and platelet abnormalities, we sought to investigate whether sleep apnea may also be considered a risk factor for venous thromboembolism (VTE). We carried out an electronic search in Medline and Scopus using the keywords "apnea" OR "apnoea" AND "venous thromboembolism" OR "deep vein thrombosis" OR "pulmonary embolism" in "Title/Abstract/Keywords", with no language or date restriction. Fifteen studies (8 case-control, 4 retrospective observational, 2 prospective case-control and 1 prospective observational) were finally selected for this systematic review. In all studies except one (14/15; 93 %), obstructive sleep apnea was found to be an independent risk factor for VTE, either deep-vein thrombosis (DVT) or pulmonary embolism (PE). In the two prospective case-control studies the risk of DVT or PE was found to be two- to three-fold higher in patients with obstructive sleep apnea than in those without. In conclusion, the current epidemiological evidence supports the hypothesis that obstructive sleep apnea may be an independent risk factor for VTE.

Haematological considerations in urology: A systematic review

Deep venous thrombosis (DVT) remains a serious and common complication of surgical procedures and is therefore an issue of importance for all urologists. In the UK, pulmonary embolism (PE) following DVT in hospitalised patients causes 32,000 deaths each year. DVT and PE represent the outcome of venous thromboembolism (VTE). The total cost for management of VTE in 2005 was approximately ₤640 million. Early risk assessment and optimising modifiable risks are paramount in order to reduce the incidence of VTE. In this article we review common risk factors for VTE and emphasise specific risk factors for urological procedures. The perioperative management of urological patients who are chronically anticoagulated is discussed. We review the literature regarding anticoagulation and its relevance to all urological procedures and mention the problems associated with new anticoagulant agents. All urologists should be familiar with the new range of anticoagulant agents due to the increasing number of patients taking them.