Triage of patients to angiography for detection of aortic rupture after blunt chest trauma: cost-effectiveness analysis of using CT.

OBJECTIVE

The purpose of this study was to evaluate the cost-effectiveness of dynamic chest CT, compared with plain chest radiography and immediate angiography, in deciding when angiography should be performed in hemodynamically stable patients with suspected aortic rupture after blunt chest trauma. The use of CT was evaluated in relation to the prior probability of aortic rupture.

MATERIALS AND METHODS

A cost-effectiveness analysis comparing six diagnostic strategies combining chest radiography, CT, and angiography in various sequences was performed. Effectiveness was expressed as survival to hospital discharge, and costs were those incurred to society. Estimates for the variables in the analysis were derived from published reports. The model was evaluated for two cohorts of patients: those undergoing and those not undergoing CT for the evaluation of other injuries. Sensitivity analysis was performed for all variables in the model with emphasis on the prior probability of aortic rupture.

RESULTS

Selecting patients for triage to angiography based on the CT findings yielded higher effectiveness at a lower cost-effectiveness ratio than doing so based on the chest radiograph, and the incremental cost-effectiveness ratio was less than $500,000 per life saved. For the cohort undergoing CT for the evaluation of other injuries, triage to angiography based on the CT findings yielded equivalent survival chances compared with immediate angiography and cost less ($1468 per patient evaluated compared with $2508). For the cohort not undergoing CT for other injuries, immediate angiography yielded the highest survival chances but was expensive, with an incremental cost-effectiveness ratio of $2 million per life saved compared with triage based on CT. In the latter cohort, immediate angiography yielded higher survival chances and had a cost-effectiveness ratio of less than $500,000 compared with the triage by CT if the prior probability of aortic rupture was 5% or more.

CONCLUSION

Selecting hemodynamically stable patients after blunt chest trauma with suspected aortic rupture for angiography on the basis of CT findings is more effective than doing so based on the findings on chest radiography and is cost-effective compared with other accepted health care programs. Immediate angiography has a high incremental cost-effectiveness ratio compared with triage by CT and is warranted only in patients not undergoing CT for the evaluation of other injuries who have a prior probability of aortic rupture of 5% or more.