Outcomes and costs of positron emission tomography: comparison of intravenous adenosine and intravenous dipyridamole.

The objective of this study was to compare the cost of intravenous adenosine and intravenous dipyridamole in positron emission tomography (PET) in patients with coronary artery disease. A retrospective, open-label, case-control, cost-effectiveness analysis was performed in the out-patient nuclear medicine department of a university hospital. Thirty-six patients underwent dipyridamole PET, and 72 matched patients underwent adenosine PET. A cost-effectiveness analysis was conducted using a direct cost accounting approach to estimate institutional costs. Key costs evaluated included acquisition cost, administration cost, monitoring cost, cost of management of side effects, and cost of follow-up care. The total cost of adenosine PET and dipyridamole PET was divided by their respective predictive accuracies to provide a total cost adjusted for efficacy. Adenosine increased heart rate and lowered systolic blood pressure to a significantly greater extent than dipyridamole. The number of patients experiencing adverse drug reactions was significantly greater for adenosine (82%) than for dipyridamole (67%), but the frequency of prolonged (> 5 minutes) and late-onset side effects was significantly greater for dipyridamole than for adenosine. The frequency of side effects requiring medical intervention was also significantly greater for dipyridamole (53%) than for adenosine (6%). Although adenosine had a significantly greater acquisition cost than dipyridamole, costs of monitoring, management of side effects, and follow-up care were significantly less for adenosine than for dipyridamole. As a result, the total cost of using dipyridamole is significantly greater ($928.00 per patient) than the total cost of using adenosine ($672.00 per patient). Based on these results, adenosine may be the drug of choice for pharmacologic vasodilation for PET.