92. Timing of postoperative anticoagulant resumption as a predictor of thromboembolic events in spine surgery

BACKGROUND CONTEXT Approximately 250,000 patients per year who are on anticoagulants must interrupt their regimen to undergo surgery or an invasive procedure that poses a high risk for blood loss. These patients must be properly managed in order to balance the prevention of thromboembolic events with excessive bleeding risk during surgery. Current guidelines for the timing of preoperative interruption and postoperative resumption of long-term anticoagulant therapy have been outlined but are based on methodologically weak observational studies and low quality data.The ambiguity of the existing data is reflected in the postoperative anticoagulant management of many spine surgeons. While some surgeons are willing to restart postoperative anticoagulants soon after surgery, others choose to wait for fear of bleeding complications. While spine surgery patients represent a unique cohort at high risk for bleeding complications, data exploring perioperative anticoagulation management for this population is lacking. PURPOSE To determine the postoperative day of anticoagulant resumption in spine surgery patients that minimizes thromboembolic complications. STUDY DESIGN/SETTING This was a retrospective cohort study of spine surgery patients within one hospital system. PATIENT SAMPLE The study included 1,441 patients who stopped medical anticoagulation for a spine surgery between the years 2008 and 2018 and who resumed anticoagulation while inpatients postoperatively. OUTCOME MEASURES The primary outcome measure was incidence of thromboembolic complication, defined as cerebrovascular accident (CVA), myocardial infarction (MI), pulmonary embolism (PE), or deep vein thrombosis (DVT). METHODS All patients undergoing fusion or decompression spinal surgery between the years 2008-2018 who were medically anticoagulated within 14 days prior to surgery and who resumed anticoagulation while inpatient were studied. Ten independent predictors of thromboembolic events were examined: postoperative day of anticoagulant resumption, age, sex, race, aspirin use, Charlson Comorbidity Index (CCI), fusion as a component of surgery, multilevel surgery, and length of stay. Multivariate logistic regression analysis was used to identify which predictors increased the odds of a thromboembolic event. RESULTS Of the 1,441 patients studied, 418 (29%) were restarted on anticoagulation on postoperative day (POD) #1, another 603 (41%) were restarted on POD#2, and 420 (29%) were restarted on POD#3 or later. Patients restarted on POD#3 or greater had an increased risk of thromboembolic events (OR 1.63, p = 0.038, 95% CI = 1.02 - 2.6). Other risk factors for clotting events included black race (OR 1.96, p = 0.007, 95% CI = 1.19 - 3.2), CCI greater than 3 (CCI 3-4: OR 2.67, p = .006; CCI 5-6: OR 3.04, p = .003; CCI 7+: OR 3.53, p CONCLUSIONS In our study of medically anticoagulated patients undergoing spine surgery, resumption of anticoagulants on POD#3 or greater increased the risk of thromboembolic complications. This finding further reinforces recent literature suggesting that a conservative approach when resuming anticoagulants after surgery can lead to serious complications. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.