Deep vein thrombosis subtree with systemic bleeding subtrees. Deep vein thrombosis (DVT) subtree showing possible outcomes following development of DVT (tree shown is for strategy of anticoagulant prophylaxis). A linkage term representing the complement of the effectiveness of withholding anticoagulant prophylaxis for reducing the risk of systemic bleeding was used to link the distal subtrees. This effectiveness term was calculated as follows: effectiveness of withholding anticoagulant prophylaxis = ((probability of systemic bleeding with LMWH) - (probability of systemic bleeding without LMWH))/(probability of systemic bleeding with LMWH). The circles represent chance nodes, and the triangles on the far right represent the outcome measure, expected utility. Numerical values under each branch are the baseline probabilities used at each chance node for the baseline case with administration of anticoagulant prophylaxis. Values to the right of each triangle are the final expected values (utility) for each state. Alive PE: survival after a pulmonary embolism; Alive w Systemic Bleed: survival after a systemic bleeding complication; CNS Bleed: progression of intracranial hemorrhage; Disabling: disabling neurological deficit; DVT: deep vein thrombosis; Non Disabling: non-disabling neurological deficit; No Sys Bleed: no systemic bleeding complication; PE: pulmonary embolism; Systemic Bleed: hemorrhagic complication not involving central nervous system.