Discordant echocardiographic grading in low gradient aortic stenosis (DEGAS study) from the italian society of echocardiography and cardiovascular imaging research network: rationale and study design.

Low‑gradient aortic stenosis (LG‑AS) is characterized by the combination of an aortic valve area compatible with severe stenosis and a low transvalvular mean gradient with low‑flow state (i.e., indexed stroke volume <35 mL/m2) in the presence of reduced (classical low‑flow AS) or preserved (paradoxical low‑flow AS) ejection fraction. Furthermore, the occurrence of a normal‑flow LG‑AS is still advocated by many authors. Within this diagnostic complexity, the diagnosis of severe AS remains challenging. Objective: The general objective of the Discordant Echocardiographic Grading in Low‑gradient AS (DEGAS Study) study will be to assess the prevalence of true severe AS in this population and validate new parameters to improve the assessment and the clinical decision‑making in patients with LG‑AS. Methods and Analyses: The DEGAS Study of the Italian Society of Echocardiography and Cardiovascular Imaging is a prospective, multicenter, observational diagnostic study that will enroll consecutively adult patients with LG‑AS over 2 years. AS severity will be ideally confirmed by a multimodality approach, but only the quantification of calcium score by multidetector computed tomography will be mandatory. The primary clinical outcome variable will be 12‑month all‑cause mortality. The secondary outcome variables will be (i) 30‑day mortality (for patients treated by Surgical aortic valve replacement or TAVR); (ii) 12‑month cardiovascular mortality; (iii) 12‑month new major cardiovascular events such as myocardial infarction, stroke, vascular complications, and rehospitalization for heart failure; and (iv) composite endpoint of cardiovascular mortality and hospitalization for heart failure. Data collection will take place through a web platform (REDCap), absolutely secure based on current standards concerning the ethical requirements and data integrity.