OBJECTIVES: German hospitals receive the same reimbursement by the statutory health insurance for CABG surgery irrespective of whether or not a rethoracotomy, which involves higher in-hospital costs, has to be performed following hemorrhage. In order to evaluate the in-hospital costs for CABG with and without rethoracotomy from the hospital perspective, a cost-analysis of CABG surgery was performed. Furthermore, the cost-effectiveness of prophylactic administration of the antihemorrhagic agent aprotinin was investigated. METHODS: The detailed resource utilization of 138 CABG patients, 68 with rethoracotomy and 70 without, was analysed based on sample of patient medical records from 7 German hospitals. Resource costs were provided by hospital administrations and supplemented by literature. The overall costs for both groups were then combined with rethoracotomy rates in patients with and without prophylactic administration of aprotinin derived from a published meta-analysis of all relevant clinical trials in open heart surgery. RESULTS: The total in-hospital costs per patient with CABG were on average DM 21,241 and increased to DM 31,326 for a CABG patient requiring rethoracotomy. Besides the costs of the rethoracotomy, the costs of intensive care were the main cost driver in patients with rethoracotomy. The meta-analysis showed with statistical significance that aprotinin can reduce the rethoracotomy rate from 5.0% to 1.8% in patients undergoing heart surgery. When combining the cost data with the results of the meta-analysis, the expected average costs per patient treated with aprotinin (including drug costs) were DM 21,432 compared to DM 21,655 per patient without aprotinin treatment. A cost-effectiveness analysis (costs per patient without rethoracotomy) resulted in a difference of DM 970 in favour of the prophylactic antihemorrhagic treatment. CONCLUSION: The analysis showed that CABG patients requiring an additional rethoracotomy generated about 47% higher costs than patients with CABG surgery only. The administration of the antihemorrhagic agent aprotinin can be recommended in the light of the reduced complication rate and improved cost-effectiveness of CABG-surgery.