Stress Echo 2030: the Novel ABCDE-(FGLPR) Protocol to Define the Future of Imaging

Stress echo (SE) 2020 is an international, multicenter, prospective, effectiveness study started in 2016 that conceptualized, disseminated and validated a new approach for functional testing within and beyond coronary artery disease (CAD). As originally planned, the study created the cultural, informatic and scientific infrastructure connecting high-volume, accredited SE labs, sharing common criteria of indication, execution, reporting and archiving SE. This approach allowed acquisition of original safety, feasibility, and outcome data in evidence-poor diagnostic fields, beyond the established core application of SE in CAD based on regional wall motion abnormality (RWMA) assessment. SE2020 standardized procedures, validated emerging signs, and integrated new information with established knowledge, helping to build a next-generation SE lab adopting the ABCDE protocol. Each and every step of ABCDE-SE provides independent and incremental prognostic information building on the prior steps and identifies distinct patient phenotypes and vulnerabilities possibly outlining different therapeutic targets: myocardial ischemia in step A, pulmonary congestion with B-lines in step B, preload reserve and left ventricular contractile reserve (LVCR) in step C, coronary microcirculation with coronary flow velocity reserve (CFVR) or real-time myocardial contrast echocardiography in step D, and cardiac autonomic balance with heart rate reserve (HRR) in step E. This shared practice can now be used as a new standard of care and a suitable platform for the next wave of studies converging towards SE 2030 and sharing with the older SE2020 study some distinct features: effectiveness study, performed in the real world with real doctors facing real clinical problems in real consecutive patients; upstream quality control of reading and direct entering of data from peripheral centers in the data bank so that evidence is obtained inside and outside highly specialized academic centers; identification of simple yet innovative objectives relevant to change the clinical practice. These features are completely different from efficacy studies, as when highly specialized centers recruit highly selected patients, the resulting data may be difficult to translate in clinical practice. For these reasons, the American Society of Echocardiography has identified already in 2013 as a top research need "the development of a registry of echocardiographic information (and eventually images) that can serve as a platform for quality improvement and clinical research. Such registry data would be accessible to the research community facilitating a broad range of clinical research on the effectiveness of echocardiography for the improvement of patient management and outcome".

SE2030 will establish the platform of evidence to build the perfect SE test, suitable for all patients, anywhere, anytime, also quantitative and operator independent. The need for such an ideal test is especially vital in our times, when the economic crisis, the increased awareness of cancer and non-cancer radiation damage, the pressing need for climate-neutral choices in health care, and the unavoidable trend to externalize health care are potent propelling forces, boosted by COVID pandemics, for the diffusion of a low cost, radiation-free, climate-friendly, and portable technique such as cardiovascular ultrasound.

Methodology. Five important aspects will be shared by SE2030 in full continuity with SE2020, with minor adaptations and implementations.

Upstream quality control. The study is a prospective registry but it is necessary to have an upstream quality control with a certified reader from each center. A mandatory quality control is necessary for conventional and innovative parameters, since the volume of activity is necessary but not sufficient to ensure the quality of reading.

Peripheral reading and inclusivity. Once the reader has been certified, the peripheral reading will be directly entered in the data bank via the Redcap program property of the Italian Society of Echocardiography and Cardiovascular Imaging. This will allow a more flexible and rapid platform, less error in data inputting and better compliance with new regulations strictly protecting privacy in clinical studies. Another feature of SE2030 is inclusivity, so that any center meeting the selection criteria can be enrolled, allowing centers traditionally outside the editorial stage but producing high quality clinical activity to contribute to generate data relevant for the scientific community.

Uniform methodology. Each laboratory will adopt the preferred choice of stress among physical, pharmacologic or pacing stress according to standardized protocol in line with guidelines recommendations. Physical exercise includes semi-supine or upright bicycle exercise, and peak or post-treadmill exercise. Pharmacologic testing will be with dobutamine or vasodilators (dipyridamole, adenosine or regadenoson) according to physician preferences, patients' contraindications, local availability and cost. Pacing stress can be performed with transesophageal atrial pacing or with external programming of a permanent pacemaker. Independent of the chosen form of stress, execution, performance, archiving and interpretation of testing will follow a standardized format with the ABCDE protocol. From the technical viewpoint of success rate, a limiting step is step D. Step D is easy and feasible with vasodilator, less easy but still highly feasible with dobutamine, not easy and less feasible with semi-supine exercise, and virtually impossible with (peak or post) treadmill exercise. Therefore, our recommendation is to use semi-supine exercise, capturing coronary flow signal in early or intermediate stages of exercise when most flow increase occurs and feasibility is still high, before it drops at higher levels of exercise. When treadmill is used, step D is skipped; if information is deemed important, a vasodilator test can be performed at 30' after the end of exercise focused on CFVR and heart rate response.

All laboratories will be granted with free artificial intelligence (AI) software and encouraged to use ultrasound enhancing agents when needed to help leading edge technology upgrade and uniformity of methods across all study laboratories .

The full spectrum of enrolled patients evaluated for clinically relevant endpoints. The various projects will include patients with known or suspected CAD (project 1), known or suspected heart failure with preserved ejection fraction (project 2), hypertrophic cardiomyopathy (HCM, project 3), status post-chest radiotherapy and chemotherapy (project 4), repaired Tetralogy of Fallot (project 7), cardio-pulmonary involvement post-COVID 19 (project 8), post-ischemic (project 10) and primary valvular heart disease (project 11) and suspected coronary vasospasm, a diagnosis frequently missed but important to recognize as a possible cause of life-threatening disease, which is easy to treat when promptly identified (project 12). The 12 protocols running on the SE-ABCDE platform are spread all over the spectrum of cardiovascular disease, from severe valvular heart disease to suspected CAD in patients with normal LV function. Potential heart donors with brain death will be evaluated to assess the suitability for donation of hearts currently dismissed on the basis of clinical history criteria but in the absence of a cardiac functional evaluation (project 9). The study will exploit and possibly contribute to upgrade the leading edge quantitative and operator-independent technology of AI-SE and cardiac strain (project 5) for image interpretation and data analysis and will also evaluate the results of SE parameters in the context of powerful environmental modulators of stress results and/or long-term outcome such as air pollutants and medical radiation exposure analyzed through big data mining with AI (project 6). The overarching aim of the study is to make SE practice more uniform, versatile, standardized, quantitative and evidence-rich, producing data potentially relevant to change clinical practice.

Sponsored by a professional scientific society. The study is investigator-driven and not industry-driven. It is endorsed by an independent-not for profit professional society (Italian Society of Echocardiography and Cardiovascular Imaging) and not sponsored by industry, although some materials useful for project completion such as AI-software will be donated by industrial partners for recruiting centers.

Inclusion criteria

Known or suspected coronary artery disease Hypertrofic cardiomiopathy Repaired Tetralogy of Fallot Primary valvular disease

Exclusion criteria

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