[Sustainability of medical imaging in cardiology]

Every year, 5 billion imaging testing are performed worldwide, and about 1 out of 2 are cardiovascular examinations. According to recent estimates, 30 to 50% of all examinations are partially or totally inappropriate. This represents a potential damage for patient undergoing imaging (who takes the acute risks of a stress procedure and/or a contrast study without a commensurable benefit), an exorbitant cost for the society and an excessive delay in the waiting lists for other patients needing the examination. Economic induction, medico-legal concern, and specialist guidelines, which do not quantitate the potential benefits against the risks of a given procedure, boost inappropriateness of all imaging techniques. In case of ionizing tests, the reduction of useless imaging testing would improve the quality of care also through abatement of long-term risks, which are linked to the dose employed. The radiation dose equivalent of common cardiological imaging examinations corresponds to more than 1000 chest x rays for a thallium scan and to more than 500 chest x-rays for a multislice computed tomography. Although a direct evaluation of incidence of cancer in patients submitted to these procedures is not available, the estimated risk (often ignored by cardiologists) of cancer according to the latest 2005 Biological Effects of Ionizing Radiation Committee VII is about one in 500 exposed patients for a Thallium scintigraphy scan, and one in 750 for a CT scan. Such a risk is probably not acceptable when a scintigraphic or radiological procedure is applied for mass screening (when the risk side of the risk-benefit balance is not considered) or when a similar information can be obtained by other means. By contrast, it is fully acceptable in appropriately selected groups as a filter to more invasive, risky and costly procedures (for instance, coronary angiography and anatomy-driven revascularization). At this point, the cardiological community, that faces the reality of limited resources, should do every effort in order to minimize inappropriate testing, since they induce an exorbitant increase in health care costs with no improvement, and possibly with a reduction in care quality.