ABC | Volume 114, Nº2, February 2020

Update Update of the Brazilian Guideline on Nuclear Cardiology – 2020 Arq Bras Cardiol. 2020; 114(2):325-429 Table 1 – Classes of recommendation and levels of evidence Classes of recommendation Class I – Conditions for which there is conclusive evidence or, in the absence of conclusive evidence, general consensus that the procedure is safe and useful/effective Class II – Conditions for which there are conflicting evidence and/or divergent opinions regarding the procedure’s safety and usefulness/effectiveness Class IIA – Weight or evidence/opinion in favor of the procedure. The majority of studies/experts approve. Class IIB – Safety and usefulness/effectiveness less well established, with no prevailing opinions in favor Class III – Conditions for which there is evidence and/or consensus that the procedure is not useful/effective and could, in some cases, be harmful Levels of Evidence Level A – Data obtained from multiple concordant large randomized trials and/or robust meta-analysis of randomized clinical trials Level B – Data obtained from less robust meta-analysis, from a single randomized trial, or from non-randomized (observational) trials Level C – Data obtained through consensus of expert opinion 1. Introduction Nuclear cardiology is a non-anatomical, physiological imaging method. The use of radioactive or radiopharmaceutical substances makes it possible to study several physiopathological mechanisms of cardiovascular disease in vivo . Via this imaging technique, it is also possible to visualize and accompany an instituted therapy’s physiological effects on cardiac function, on the cellular and biochemical level. Of all the applications of nuclear medicine in cardiology, scintigraphy or myocardial perfusion imaging with technetium-99m-labeled radiopharmaceuticals synchronized with electrocardiogram (Gated-SPECT), is the most common exam in clinical practice. For this reason, this technique will be the most discussed in these Guidelines. Recent years have, however, seen a growing concern among the scientific community regarding rational and optimized use of ionizing radiation in medicine. Cardiovascular imaging, moreover, encompasses all functional and anatomical imaging techniques and should, in this context, be used rationally and cost-effectively. Other applications of nuclear medicine in cardiology have also emerged and gained prominence during the past decades, especially positron emission tomography (PET) for the study of coronary flow reserve, cardiac sympathetic activity, and inflammatory/infectious processes, and cardiac amyloidosis (CA). All of these aspects have been taken into consideration and will be covered in detail in the chapters developed herein. Guidelines recommendations are highly valuable tools for medical activity of the highest quality. The objective is to support and aid doctors in making decisions regarding their patients, by elaborating orientations which may be useful as part of the decision-making process. No Guidelines, however, should be replaced by the abilities, experience, and clinical judgments of specialized professionals who are have the final say in their decisions concerning each individual patient. In general, whenever possible and applicable, classifications of recommendation have been adopted for indicating cardiac scintigraphy, supported by levels of evidence, in accordance with the recommendations established by classical cardiology guidelines (Table 1). Based on current evidence, this document, which does not function as a substitute, practically and objectively adds important data to and updates the Brazilian Cardiology Society’s (SBC) First Guidelines and Update on Nuclear Cardiology , both of which were published by the Brazilian Archives of Cardiology (Arquivos Brasileiros de Cardiologia), in 2002 and 2005, respectively. As in the previously mentioned documents, those who participated in the elaboration of these Guidelines are considered specialists in their respective areas and were, for this reason, chosen to develop the chapters thereon. The committed involvement of all colleagues representing the SBC and the Brazilian Society of Nuclear Medicine (SBMN) have made the elaboration of these new update of Brazilian Guidelines on Nuclear Cardiology possible. It is our hope that they will be of great use, especially to Cardiologists and Nuclear Medicine and Clinical Physicians in Brazil. The Organizing Committee appreciates the collaboration of all those involved. 2. Addendum to the ISCHEMIA Study* At the time of publication of this guideline, the International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) had not been published yet, although the main findings were presented on November 16, 2019 at the American Heart Association (AHA) annual congress in Philadelphia, USA, available on the study’s website. Considering its importance for medical decision-making and the potential implications for nuclear cardiology, a few relevant concerns should be highlighted on the findings available so far: 1. The main objective of the ISCHEMIA study was to assess whether patients (P) with at least moderate ischemia on a functional examination would benefit from myocardial revascularization (coronary artery bypass grafting or percutaneous coronary intervention) added to optimal medical therapy). Were randomized 5,179 patients with stable CAD and myocardial ischemia documented by one of many different methods (myocardial perfusion scintigraphy, stress echocardiography, cardiac magnetic resonance imaging, exercise testing not associated with cardiac imaging). These noninvasive methods were used to define the etiology of chest pain and for cardiovascular 330