Economics of myocardial perfusion imaging in Europe - The EMPIRE study

Background Physicians use myocardial perfusion imaging to a variable extent in patients presenting with possible coronary artery disease. There are fe w clinical data on the most cost-effective strategy although computer model s predict that routine use of myocardial perfusion imaging is cost-effectiv e. Objectives To measure the cost-effectiveness of four diagnostic strategies in patients newly presenting with possible coronary artery disease, and to compare cost-effectiveness in centres that routinely use myocardial perfusi on imaging with those that do not. Methods We have studied 396 patients presenting to eight hospitals for the diagnosis of coronary artery disease. The hospitals were regular users or n on-users of myocardial perfusion imaging with one of each in four countries (France, Germany, Italy, United Kingdom). Information was gathered retrosp ectively on presentation, investigations! complications, and clinical manag ement, and patients were followed-up for 2 years in order to assess outcome . Pre- and post-test probabilities of coronary artery disease were computed for diagnostic tests and each test was also assigned as diagnostic or part of management. Diagnostic strategies defined were: 1: Exercise electrocard iogram/coronary angiography, 2: exercise electrocardiogram/myocardial perfu sion imaging/coronary angiography, 3: myocardial perfusion imaging/coronary angiography, 4: coronary angiography. Primary outcome measures were thr: c ost and accuracy of diagnosis, the cost of subsequent management. and clini cal outcome. Secondary measures included prognostic power, normal angiograp hy rate, and rate of angiography not followed by revascularization. Results Mean diagnostic costs per patient were: strategy 1: pound 490, 2: p ound 409, 3: pound 460, 4: pound 1253 (P<0.0001). Myocardial perfusion imag ing users: pound 529, non-users pound 667 (P=0.006). Mean probability of th e presence of coronary artery disease when the final clinical diagnosis was coronary artery disease present were. strategy 1: 0.85, 2: 0.82, 3: 0.97, 4: 1.0 (P<0.0001), users 0.93, non-users 0.88 (P=0.02), and when coronary a rtery disease was absent, 1: 0.26, 2: 0.22, 3: 0.16, 4. 0.0 (P<0.0001), use rs 0.21, non-users 0.20 (P=ns). Total 2-year costs (coronary artery disease present/absent) were: strategy 1: pound 4453/pound 710, 2. pound 3842/poun d 478, 3. pound 3768/pound 574, 4: pound 5599/pound 1475 (P<0.05/0.0001), u sers: pound 5563/pound 623, non-users: pound 5428/pound 916 (P=ns/0.001). P rognostic power at diagnosis was higher (P<0.0001) and normal coronary angi ography rate lower (P=0.07) in the scintigraphic centres and strategies. Nu mbers of soft and hard cardiac events over 2 years and final symptomatic st atus did not differ between strategy or centre. Conclusion Investigative strategies using myocardial perfusion imaging are cheaper and equally effective when compared with strategies that do not use myocardial perfusion imaging, both for cost of diagnosis and for overall 2 year management costs. Two year patient outcome is the same.