Aortic stenosis (AS) is a common valvular heart disease whose prevalence increases markedly with age-approximately 2-4% in individuals aged 65 years and older, and up to 3.4% for severe AS in those over 75. Degenerative calcific AS predominates in high-income countries, whereas rheumatic disease remains a major cause in low-income regions. With global population aging, the disease burden of AS continues to rise.
Transcatheter aortic valve replacement (TAVR/TAVI), owing to its minimally invasive nature, has become an important treatment option for severe AS and selected aortic regurgitation patients, expanding from high-surgical-risk populations to those at intermediate and low risk. In recent years, the number of TAVR procedures in many regions has surpassed or approached that of surgical aortic valve replacement, and major clinical guidelines have elevated TAVR to a recommended standard therapy.
Conventional TAVR relies on combined fluoroscopic and echocardiographic guidance. However, perioperative complications remain frequent in elderly and high-risk patients, particularly acute kidney injury (AKI), which significantly increases short- and long-term mortality. Contrast exposure during the procedure is a major contributor to AKI; thus, clinical practice increasingly favors strategies that minimize contrast use, such as low-dose and low-kV imaging. Elevated contrast concentration in the renal tubules increases viscosity, prolongs renal exposure, and can lead to tubular injury and renal dysfunction. Continuous radiation exposure during vascular access, device positioning, valve deployment, and post-release assessment also poses safety concerns for both patients and medical staff.
Echocardiography-only guidance for TAVR has therefore emerged as an attractive alternative, with the potential to replace fluoroscopy and contrast for anatomical visualization and device positioning, thereby reducing radiation exposure and contrast-related kidney injury. However, no prospective randomized study has directly compared echocardiography-only guidance with conventional fluoroscopy-plus-echocardiography guidance, and current evidence remains preliminary.
To address this gap, a randomized controlled trial was designed to evaluate whether echocardiography-only guidance is non-inferior to combined fluoroscopic and echocardiographic guidance in terms of device success, while also assessing the safety, efficacy, and clinical feasibility of both approaches.