Routine Postoperative Aspirin for VTE Chemoprophylaxis in Primary Total Ankle Arthroplasty

Abstract

Category: Ankle Arthritis; Ankle; Other Introduction/Purpose: The use of low-dose aspirin for postoperative venous thromboembolism (VTE) chemoprophylaxis has been widely studied and validated in adult reconstruction surgery with little to no reported adverse reactions. In total ankle arthroplasty (TAA) literature, low-molecular-weight heparin (LMWH) has been the predominant chemoprophylactic agent used, despite little evidence supporting it. To date, no studies have assessed the role of aspirin for VTE chemoprophylaxis after total ankle arthroplasty and no formalized clinical practice guideline exists. The purpose of this study was to evaluate outcomes of a large consecutive series of patients undergoing primary TAA at a single institution, in relation to routine postoperative aspirin administration. Methods: A prospective telephone survey and retrospective chart review was performed of patients undergoing primary TAA at a single institution by two fellowship trained foot and ankle surgeons. All patients were prescribed oral aspirin 81 mg BID for at least 2 weeks postoperatively, (or while weight-bearing was restricted). The primary outcome variable was postoperative development of deep vein thrombosis (DVT), pulmonary embolism (PE), or VTE related mortality within 3 months postoperatively. Venous ultrasounds were also queried. The secondary outcome variable was assessment of aspirin related adverse reaction including delayed wound healing and gastrointestinal (GI) bleeding. Patients with a history of bleeding disorder or history of prior VTE requiring non-Aspirin VTE chemoprophylaxis were excluded. Results: There were 217 patients included for retrospective review, and 81 patients completed the telephone survey (34% response rate). Concomitant procedures included gastrocnemius recession (104), teno-Achilles lengthening (20), ligament repair (17), tendon repair (3), tendon transfer (12), and plantar fasciectomy (1). The cohort included 119 males (54.8%), with a mean age 62.6 +/- 10.3 years (range 24 to 88), and mean BMI 30.6 +/- 5.6 (range 21.3 to 52.6). There were no GI bleeding or VTE events, yet 46/217 (21.2%) cases of delayed wound healing. Eleven patients underwent venous ultrasounds that all were negative. Sex (p=0.458), age (p=0.443), and BMI (p=0.335) were not associated with delayed wound healing, but current/former smoking status trended toward significant association (p=0.077). Time to weight-bearing was mostly bi-modal, between 1.5-3.5 weeks (37.8%) or 5.5-7.5 weeks (45.1%). Time to weight-bearing approached significance with delayed wound healing (p=0.05), which may represent surgeon intervention to promote healing. Conclusion: This study demonstrates effective use of aspirin in preventing VTE events after primary TAA in patients without risk factors for VTE and PE, which is cheaper and more widely available all around the world. Further randomized controlled studies may better elucidate any role of aspirin with regards to delayed wound healing, which had an an approximate incidence of 20% in our cohort. Limitations of the study include those inherent to a retrospective review, such as lack of a control group.