Clinical efficacy of risk-stratified prophylaxis with low-dose aspirin for the management of symptomatic venous thromboembolism after total hip arthroplasty

Pulmonary thromboembolism (PTE) and deep vein thrombosis (DVT) are serious complications after total hip arthroplasty (THA). Aspirin has been considered a safe and cost-effective prophylaxis for venous thromboembolism (VTE), and there have been some reports about the incidence of PTE (0%–0.57%) and DVT (0.1%–0.35%) with low-dose aspirin for prophylaxis after THA. The aim of this study was to investigate the incidence of postoperative symptomatic VTE in our hospital and to evaluate the clinical efficacy of our prophylactic regimen. We retrospectively reviewed the medical records of consecutive patients who underwent THA in our hospital between 2011 and 2016. A total of 3295 hips (male: 337 patients, 365 hips; female: 2527 patients, 2930 hips) were enrolled in this study. Patients were divided into low-risk and high-risk groups. Low-risk patients were administered aspirin (100 mg/day) for 28 days postoperatively. High-risk patients, such as those diagnosed with obesity and/or with a history of VTE, received anticoagulants (enoxaparin or edoxaban) for 5 days postoperatively, followed by a dose of aspirin for 28 days. Based on our criteria, 218 of 3295 hips were considered high risk. No VTE-related mortality was observed. One patient developed symptomatic PTE, and one patient developed symptomatic DVT. Both were successfully treated. Postoperative fatal bleeding or bleeding from any organ such as gastrointestinal and cerebral hemorrhage were not observed. A low incidence (0.03%) was observed for symptomatic DVT and PTE. This study demonstrated that the hospital's risk-stratified protocol using low-dose aspirin or anticoagulants was clinically effective in preventing symptomatic VTE. These results were considerably better than those reported from Western countries. However, all patients in this study were the Japanese. It was unclear whether similar results were given to non-Japanese patients. Therefore, this protocol needs severe carefulness to be applied to non-Japanese populations.