ABC | Volume 114, Nº2, February 2020

Update Update of the Brazilian Guideline on Nuclear Cardiology – 2020 Arq Bras Cardiol. 2020; 114(2):325-429 risk stratification, a management approach established in clinical practice that is not invalidated by the findings of the study. Prior knowledge indicates that patients with lower ischemic burden have a better prognosis than individuals with larger and more intense ischemia; 2. The ISCHEMIA trial demonstrated no benefit of myocardial revascularization (Invasive Group - IG) versus optimal medical therapy (OMT) to reduce the major outcomes of “death” and “acute myocardial infarction.” Despite the methodological differences, these results were somewhat similar to those of the COURAGE study. It is noteworthy that the mortality curves began to separate after two years of medical follow-up, apparently benefiting the IG and potential long-term implications, which justified the increased clinical follow-up of P, underway at the moment. Note that the IG had an improved quality of life assessment, reduced frequency of angina and lower use of specific medication compared to the OMT group; 3. The ISCHEMIA trial is one of the most relevant studies on stable CAD, with important messages for clinical practice. The validity of the results is emphasized for the population sample evaluated in the study and for the definitions of ischemia and its severity levels employed. However, for exclusion situations, such as P with left main disease, recent acute coronary syndrome, angioplasty in the previous 12 months, ejection fraction < 35% and progressive or unstable symptoms, prior knowledge remains unchanged. Both CAD and ischemic heart disease represent a broad spectrum of patients, with inherent heterogeneity and important prognostic implications (extensive evidence base in the literature and described in detail in the current guideline). Were excluded from the trial an impressive number of P that had at least moderate angina and ischemia in the absence of coronary obstructions, showing the diversity of the disease and the value of functional assessment; 4. The main question is whether the ISCHEMIA study has properly evaluated a significant number of P with moderate/severe ischemia, aiming to determine whether myocardial revascularization adds prognostic benefit to these patients, as documented by scintigraphy, which was not the exclusive method of documentation. There was the inclusion (randomization) of cases with nonexistent or mild ischemia (12% of the total randomized), which is surprising for a study that was initially intended to include only patients with moderate to severe ischemia. There was also a change in the criteria for inclusion of P with severe ischemia in the study, with a significant number based on the results of exercise testing, without imaging, a decision made after the study was in progress. From this change, the percentage of these P that would effectively have severe myocardial ischemia on scintigraphy is questioned; 5. Therefore, the Editorial Board of this guideline believes that the definitive analysis of the results will only be possible after the formal publication of the trial results. Editorial Board of the New Update of The Brazilian Guideline on Nuclear Cardiology, February 2020 3. The Application of Nuclear Medicine Techniques to Justify Financial Resources Available for Attending Cardiology Patients in Brazil 3.1. Introduction Cardiovascular diseases are the main cause of death in Brazil, and they are responsible for 30% of deaths worldwide every year. 1 They are responsible for approximately 8% of total healthcare costs in Brazil, a figure which has been increasingly annually, in parallel with population aging. 1 Teich and Araújo estimated that in 2011, approximately 200,000 events associated with acute coronary syndromes occurred in Brazil, entailing a massive impact of 3.88 billion Brazilian reals, considering only hospital and indirect costs, associated with loss of productivity. 2 Considering these findings, it has been demonstrated that (preventive) measures play a crucial role in reducing morbidity and mortality, and they should be a priority in national healthcare policy design, as they have profound additional impacts on reducing costs and maintaining productivity. Another significant point, however, which has contributed to reducing the outcome of “cardiovascular death” and to justifying expenses, involves the use of tools which make accurate diagnosis of a determined condition possible (?) and which aid and guide the conduct of physicians, based on these results. Myocardial perfusion scintigraphy (MPS) plays a significant role in justifying financial resources for attending patients with established or potential cardiovascular disease. 3.2. Cost-Effectiveness in Comparison with Cardiac Catheterization One of the main fundaments of MPS is its good ability to identify low-risk patients, who do not require invasive intervention, in spite of established coronary disease, such as anatomical lesions on coronary angiography. 3 Observational studies in the 1990’s have demonstrated that MPS was able to identify high- and low-risk groups, resulting in reduced costs for patients with coronary artery disease (CAD) and avoiding procedures that are not associated with improved patient health outcomes. A major prospective study carried out in the United States of America (USA) recruited 11,372 patients with stable angina, who were referred to either MPS or cardiac catheterization. Patients were adjusted by clinical risk, and the costs of direct cardiac catheterization (aggressive strategy) were compared to initial scintigraphy followed by selective catheterization in high-risk patients (conservative strategy). Although both strategies had similar adverse outcomes, such as cardiac death and non-fatal myocardial infarction, revascularization rates were higher (between 13% and 50%) in patients who underwent catheterization directly. 4 This reflex of revascularizing anatomical lesions which do not determine ischemia led to unnecessary associated medical costs of around 5,000 dollars per patient in this study. 4 Currently, the use of medical resources for conditions that do not have consequences for patients or that could be managed conservatively is known as “overtreatment.” 5 The study of *To access the Addendum bibliography, go to: https://sbc-portal.s3.sa-east-1.amazonaws.com/diretrizes/Publicacoes/2020/ Bibliografia-adendo/Bibliografia_ADENDO_INGLES_24-01-2020.pdf 331