1. Making Decisions About Antithrombotic Therapy in Heart Disease
Mark H. Eckman, MD, Herbert J. Levine, MD, FCCP, Stephen G. Pauker, MD 
CHEST 
Volume 108, Issue 4, Pages 457S-470S (October 1995)
DOI: /chest.108.4_Supplement.457S
Copyright © 1995 The American College of Chest Physicians Terms and Conditions

2. FIGURE 1
Decision node and Markov states for anticoagulation decision tree. The square node (left) denotes the initial decision. The curly bracket indicates that the same Markov subtree (rectangular node surrounding a solid triangle with circles) is used for both decisions. In this abbreviated version of the Markov model, there are 11 states of health. Patients receiving anticoagulants start the simulation in the state OK ON WARFARIN, while those not receiving anticoagulants start in the state OK OFF WARFARIN.
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3. FIGURE 2
Patients face the same chance events during each cycle of the simulation. The first pair of circular chance nodes denote the chance of thromboembolic events. The second pair of chance nodes denote the chance of bleeding complications, while the final chance node denotes the chance of dying from demographic-related causes.
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4. FIGURE 3
One-way sensitivity analysis examining the marginal cost-effectiveness of anticoagulation as a function of the annual rate of thromboembolic events. Three points on this curve are illustrated corresponding to a low, intermediate, and high rate of thromboembolic events, mitral stenosis in normal sinus rhythm, rheumatic mitral stenosis in atrial fibrillation, and atrial fibrillation with a prior embolus, respectively.
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5. FIGURE 4
Two-way sensitivity analysis of relation between the rates of thromboembolic and bleeding events. A combination of these two parameters corresponds to a point on the graph. Three points are shown, corresponding to mitral stenosis in normal sinus rhythm (NSR), mitral stenosis and atrial fibrillation, or atrial fibrillation and a prior embolus. For any combination of thromboembolic risk and bleeding risk, if the point lies below the line, anticoagulation is the optimal choice.
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6. FIGURE 5
Three-way sensitivity analysis of relation among the rates of thromboembolic and bleeding events and the efficacy of anticoagulation. The format is similar to Figure 4, with each line corresponding to a different efficacy.
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7. FIGURE 6
Two-way sensitivity analysis of relation between the risk of thromboembolic and bleeding events calibrated for use with Table 6. A second horizontal axis depicts the probability of ischemic stroke, corresponding to the risk weight for thromboembolic events in the horizontal axis above. For any set of patient characteristics, the clinician can calculate a patient-specific risk for both ischemic stroke and major bleeding events. The two diagonal threshold lines represent a lower bound (upper line) and an upper bound (lower line) for the baseline rate of bleeding in low-risk patients receiving warfarin. Two points are shown, corresponding to a 67-year-old with atrial fibrillation and a history of GI bleeding, and a 72-year-old with atrial fibrillation, noninsulin-dependent diabetes (NIDDM), and hypertension (HTN).
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8. FIGURE 7
One-way sensitivity analysis examining the marginal cost-effectiveness of anticoagulation with warfarin as a function of the efficacy of aspirin in preventing thromboembolic events. Above the threshold, marked by a vertical dashed line, aspirin is less costly and more effective than anticoagulation with warfarin.
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9. FIGURE 8
Two-way sensitivity analysis of relation between a patient's propensity for thromboembolic and bleeding events for four different therapies. Moving from the upper left to the bottom right of the figure represents an increasing intensity of antithrombotic therapy (therapies are increasingly efficacious but present the patient with an increasing risk of bleeding). Patients who have a low risk of thromboembolism but a high risk of bleeding do best with no antithrombotic therapy (eg, Pt A), while patients who have a high risk of thromboembolism and a lower risk of bleeding may do better with a combination of warfarin and aspirin. Patient D has a greater propensity to bleed, but the risk of thromboembolism is so high, that combined treatment with warfarin and aspirin is indicated.
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