Low productivity of stress cardiac magnetic resonance imaging for screening of coronary artery disease Marko Boban, 1,2 Vladimir Pesa 1 Coronary artery disease (CAD) is one of the most important chronic comorbidities in the general population, resulting in tre- mendous societal cost. 1 It is responsible for an annual death toll of 4 000 000 throughout 28 European Union (EU) member states, of which 700 000 occur at an age younger than 65 years. 2 Despite significant efforts to identify novel bio- markers, genome-wide-associated studies and conventional imaging modalities, the challenge of developing effective screen- ing tools has still to be tackled in a suffi- ciently resourceful manner. 1 Wider availability of diagnostic machin- ery, as well as their partial support by guidelines, has made some procedures such as adenosine stress cardiac magnetic resonance (CMR) very popular. 3 4 With thoughtful application, adenosine stress CMR can offer clinically relevant prog- nostic information and affect subsequent therapeutic decisions. However, when used to screen for CAD, stress CMR is a questionable practice. If you consider that the effects of negative stress CMR perfu- sion on rates of long-term major adverse cardiovascular events are very similar to those accomplished by treadmill testing, the cost-efficiency of the former is debateable. 3 If we were to try to screen the EU popu- lation for high-risk cases—theoretically and effectively covering 1.6 million people expected to have acute coronary syndrome (ACS) during the next year—and if this were to be undertaken by five CMR centres per 28 EU member states, each per- forming 10 examinations a day, this labour-intense task would take 4.8 years. The cost, using average European prices (around 643 euro), would be 1.03 billion euro per intervention, and that is assuming that the costs of machines, education, technical and software maintenance are not included and that labour, electricity and hospital space are secondarily com- pensated. 5 Indirect medical costs, from losing productivity to attend diagnostic procedures, would also be very high. In addition, when trying to calculate the number needed to prevent one ACS in this highly selected, but still theoretical, popu- lation of high-risk individuals, it has been estimated that five examinations would be needed to prevent one ACS (risk 0.0025 and high-risk individuals of 1.6 million, with 0.005 prevalence), hence screening would need to be conducted on a very large population. 2 There is also the important issue with the adenosine stress CMR test of the high number and proportion of negative diag- nostic reports. A multicentric study on the cost efficiency of adenosine CMR versus percutaneous coronary angiography (PCA) reported a remarkable three out of four negative tests (73%; n=1983/2717 total), with a further 6% of non-diagnostic cases (n=163/2717), totalling nearly 80% of examinations that basically did not find the disease, and shadowing the light of efficiency. 5 Although this is conceptually in line with a high negative predictive value of stress CMR for excluding CAD, at the same time it provides little informa- tion on how exactly to prevent a major adverse cardiac outcome. From the clinical perspective, it is also of concern not to see the results of previous treadmill testing in most of the registry-based studies concern- ing CMR and prognosis or economic effi- ciency. 56 Even more interesting is the fact that numerous studies focusing on the cost-efficiency of CMR used partially flawed settings: comparing the functional test of CMR (optimal for excluding disease) with PCA (optimal for diagnosing and/or treatment), where the latter is only functional in exceptional cases such as fractional flow reserve studies. These studies therefore usually ended with the convenient conclusion that one prevented PCA represents a saving of money, while resources spent on the large number of reports within the referral range, as well as on those with positive or unclear findings, requiring subsequent diagnostics (some of which also included PCA), were not addressed at all. 5 6 In these propensity- unmatched situations, the chances are inevitably in favour of a single stress CMR examination over a single PCA, which could be of concern otherwise to the national health authorities of the member states, and assets being paid from govern- ment funds. In addition, since most nega- tive stress CMR examinations finish without affecting subsequent diagnostic/ therapeutic interventions, there might be an ethical challenge from the standpoint of performing unessential examinations on a vast number of patients. One should, however, note that stress CMR is very valuable in selected patients with known CAD, after a major cardiovas- cular event or revascularisation treatment, for testing the objectivity of symptoms, functionality of stenoses and global risk assessment. 3 Positive results of stress CMR testing—that is, inducible stress per- fusion deficits—are the only category that would benefit from revascularisation treat- ments, considering control of symptoms, quality of life and rate of major adverse events. 7 In these circumstances, there are even more problems with the previously noted high proportion of non-diagnostic or falsely positive results, especially in patients with diabetes, hypertensive heart disease, aortic stenosis or other categories, in whom constitutive stationary perfusion deficits commonly exist. 8 From a technical point of view, because of a short half-life and other character- istics, adenosine stress testing has an excel- lent safety profile and tolerability in patients with ischaemic heart disease or others. 9 Gadolinium-based contrasts also have good tolerability and low levels of adverse reactions. The rate of serious side effects such as nephrogenic system fibrosis is fortunately low and in most cases pre- ventable. However, long-term effects of gadolinium depositions in various tissues is still of unknown significance. 10 Central nervous system deposits have been found to be associated with multiple contrast applications, depending on the chemical structure of the contrast, which might conceal potential for long-term neural toxicity. 10 Owing to the potential toxicity of gadolinium, it seems reasonable not to overuse contrast examinations. This is par- ticularly true in cases with a high chance of a negative result, as well as those with a low likelihood of relevant subsequent therapeutic interventions, or in those with no reasonably defined significant positive effects on prognostic course. Unnecessary contrast applications could be circum- vented in cases in which risk assessment 1 Department of Cardiology, University Hospital TTO, Medical Faculty University of Rijeka, Zagreb, Croatia; 2 Department of Internal Medicine, Medical Faculty “J.J. Strossmayer”, University of Osijek, Opatija, Croatia Correspondence to Assistance Professor Marko Boban, Department of Cardiology, University Hospital TTO, Medical Faculty University of Rijeka, Medical Faculty “J.J. Strossmayer”, University of Osijek, Osijek 51410, Croatia; marcoboban@yahoo.com Boban M, Pesa V. Postgrad Med J Month 2017 Vol 0 No 0 1 Editorial PGMJ Online First, published on January 10, 2017 as 10.1136/postgradmedj-2016-134653 Copyright Article author (or their employer) 2017. Produced by BMJ Publishing Group Ltd under licence.