There was not enough evidence to support or refute a recommendation regarding heparin bridge therapy in reducing thromboembolism in chronically anticoagulated patients (Level B).
Bottom line: These are the most up-to-date guidelines for anticoagulant and antiplatelet agents in patients with transient ischemic attacks and strokes undergoing procedures, but further research is needed in many areas.
Citation: Armstrong MJ, Gronseth G Anderson DC, et al. Summary of evidence-based guideline: periprocedural management of antithrombotic medications in patients with ischemic cerebrovascular disease: Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2013;80:2065-2069.
Extended Prophylaxis with Aspirin Was Noninferior to Extended Prophylaxis with Low-Molecular-Weight Heparin
Clinical question: Is aspirin as effective as low-molecular-weight heparin (LMWH) for the extended prophylaxis of venous thromboembolism (VTE) after total hip arthroplasty (THA)?
Background: Deep vein thrombosis (DVT) and pulmonary embolism (PE) are common complications after THA. After initial prophylaxis, LMWH given for up to 30 days has been shown to reduce VTE compared with placebo. However, LMWH is costly and may increase the risk of minor bleeding. Aspirin is a potentially simple, low-cost alternative.
Study design: Randomized, placebo-controlled trial.
Setting: Twelve university-affiliated orthopedic hospitals in Canada.
Synopsis: Patients undergoing elective THA without hip fracture, metastatic cancer, or bleeding precluding anticoagulants were eligible. All patients received dalteparin for 10 days and were then randomized to aspirin 81 mg daily or to continue dalteparin. The primary outcome was symptomatic proximal DVT or PE during 90 days’ follow-up. The study was terminated early due to slow enrollment. At that time, 2,364 patients had been enrolled, and an analysis by an independent data safety and monitoring board determined that continuing the study was unlikely to alter the main findings. Extended prophylaxis with aspirin was noninferior to LMWH for the primary outcome, which occurred in 0.3% vs. 1.3%, respectively (95% CI, -0.5% to 2.5%, P<.001 for noninferiority). There were no significant differences in major or minor bleeding.
Though the early termination is a concern, the sample size was large and the results do not suggest inadequate power as a reason for lack of superiority for LMWH. Also, all patients received 10 days of LMWH, which indicates a period of LMWH after discharge will still be needed for most patients prior to initiating aspirin.
Bottom line: After initial LMWH prophylaxis for 10 days, extended prophylaxis with aspirin can be considered, particularly for patients for whom LMWH may not be feasible.
Citation: Anderson DR, Dunbar MJ, Bohm ER, et al. Aspirin versus low-molecular-weight heparin for extended venous thromboembolism prophylaxis after total hip arthroplasty: a randomized trial. Ann Intern Med. 2013;158:800-806.
Symptomatic Subsegmental Pulmonary Embolism (PE) Has a Prognosis Similar to Proximal PE
Clinical question: Is the prognosis of a symptomatic subsegmental pulmonary embolism (PE) similar to that of a more proximal PE?
Background: The use of multidetector computed tomography angiography (CTA) has allowed for better assessment of the pulmonary vasculature and increased detection of distal emboli. Prior studies have raised questions on the clinical importance of subsegmental PE but have been limited by small size or retrospective design.
Study design: Combined data from two prospective trials of management of suspected PE.
Setting: Twelve hospitals in the Netherlands and four tertiary-care emergency departments in Canada.
Synopsis: The study cohort consisted of 3,769 patients with suspected PE, of which 2,688 underwent CTA. Of patients diagnosed with PE, 15.5% had isolated subsegmental emboli. All patients were treated with anticoagulation. During three months of follow-up, the incidence of symptomatic recurrence for subsegmental PE was similar to patients with proximal PE (3.6% vs. 2.5%, respectively). The mortality rates for patients with subsegmental and proximal PE were also similar (10.3% vs. 6.3%, respectively).