Suspected acute pulmonary emboli: cost-effectiveness of chest helical computed tomography versus a standard diagnostic algorithm incorporating ventilation-perfusion scintigraphy

Background: There is a controversy regarding the investigation of patients with suspected acute pulmonary embolism (PE). Aims: To compare the cost-eff ectiveness of alternative methods of diagnosing acute PE. Chest helical com puted tomography (CT) alone and in combination with venous ultrasound (US) of legs and pulmonary angiography (PA) were compared to a conventional algo rithm using ventilation-perfusion (V/Q) scintigraphy supplemented in select ed cases by US and PA. Methods: A decision-analytical model was constructed to model the costs and effects of the three diagnostic strategies in a hypothetical cohort of 100 0 patients each. Transition probabilities were based on published data. Lif e years gained by each strategy were estimated from published mortality rat es. Schedule fees were used to estimate costs. Results: The V/Q protocol is both more expensive and more effective than CT alone resulting in 20.1 additional lives saved at a (discounted) cost of $ 940 per life year gained. An additional 2.5 lives can be saved if CT replac es V/Q scintigraphy in the diagnostic algorithm but at a cost of $23,905 pe r life year saved. Conclusions: The more effective diagnostic strategies are also more expensi ve. In patients with suspected PE, the incremental cost-effectiveness of th e V/Q based strategy over CT alone is reasonable in comparison with other h ealth interventions. The cost-effectiveness of the supplemented CT strategy is more questionable.