Perioperative Low-Molecular-Weight Heparin and Neuraxial Anesthesia: A Review of Current Practice Guidelines

Abstract

Over the past nine years, the wide acceptance of low-molecular-weight heparins (LMWHs) in the United States has been the result of this class of drugs excellent safety and efficacy profile across multiple applications to prevent and treat arterial and venous thromboembolic disease. There has been concern, however, about the safety of using anticoagulant-based deep vein thrombosis (DVT) prophylaxis with regional anesthesia. This concern arose from a number of case reports in which the development of spinal hematoma was linked to the administration of LMWHs in patients receiving concomitant neuraxial anesthesia. In December 1997, the FDA issued an advisory about these adverse events indicating that there might be a relationship between epidural hematoma and neuraxial anesthesia in patients receiving LMWH's. Manufacturers of LMWHs subsequently added a boxed warning to their prescribing information alerting clinicians to these potential effects. Subsequently, the American Society of Regional Anesthesia (ASRA) produced guidelines with respect to the safe use of anticoagulants in patients receiving neuraxial anesthesia/analgesia based upon the available case reports and evidence. Upon review of the data, the inherent efficacy and widespread acceptance of LMWHs for prophylaxis of DVT, it may be concluded that conscientious use of LMWHs and neuraxial anesthesia may be provided safely in nearly every situation if attentive towards proper administration relative to the use of anesthesia. The fact that regional anesthesia reduces the risk of venous thromboembolism when other pharmacologic prophylaxis is not used after joint replacement surgery is well documented (Table 1).1,2,3,4 Further, it is recognized that in joint replacement, clot formation begins intraoperatively. Thus the use of neuraxial anesthesia and post-operative analgesia combined with early pharmacologic prophylaxis would appear to be the most efficacious approach toward preventing thromboembolic complications. The purpose of this review is to summarize the proper guidelines for the management of patients undergoing joint replacement surgery in the context of pharmacologic DVT prophylaxis and neuraxial anesthesia and analgesia.