Perioperative Management of Patients on Oral Anticoagulants: A Decision Analysis

Abstract

Background . To better inform clinicians on the optimal management of patients on oral anticoagulation who need to undergo surgery or invasive procedures, the authors performed a decision analysis examining whether a perioperative aggressive or minimalist strategy results in greater quality-adjusted survival. Methods . A decision analysis model was created comparing withholding warfarin (minimalist strategy) to withholding warfarin and administering treatment-dose subcutaneous low-molecular-weight heparin (LMWH) or intravenous heparin perioperatively (aggressive strategy). The base-case analysis examined a hypothetical 60-year-old hypertensive individual with mechanical aortic valve replacement undergoing major abdominal surgery. A probabilistic sensitivity analysis was performed using a Monte Carlo simulation with quality-adjusted life expectancy (QALE) as the outcome. Secondary analyses examined patients with a mechanical mitral valve and atrial fibrillation. Sensitivity analyses were performed for each variable. Results . Under the base-case scenario, the minimalist strategy was preferred for 78% of trials in the Monte Carlo simulation, with a mean benefit of 0.003 years (95% confidence interval, -0.005 years to 0.011 years). Sensitivity analyses based on point estimates indicate that the aggressive strategy is preferred when the annual stroke rate is >5.6% or the increase in postoperative major bleeding induced by heparin is <2.0%; however, the benefit is small over the range of plausible values. Conclusions . For most patients with a mechanical aortic valve or atrial fibrillation undergoing major surgery, a minimalist strategy of simply withholding oral anticoagulation provides similar QALE as an aggressive strategy of administering perioperative subcutaneous LMWH or intravenous heparin. The aggressive therapy provides greater QALE for patients at higher risk of stroke (e.g., mechanical mitral valves), although the benefit is small.