Primary and Secondary Endpoints:
The primary endpoint for this study was overall mortality throughout the follow-up period extending to 9 years after the TAVR procedure. Secondary endpoints included aortic valve revision, myocardial infarction, newly recognized arrhythmia, new-onset angina, cardiac arrest, coronary artery bypass grafting, coronary angioplasty, stroke, endocarditis, and prosthetic valve insufficiency.
The independent variables included: ELI values calculated based on the native aortic valve and the effective aortic orifice area (EOA) after TAVR, demographic data, type of prosthesis, and presence of preoperative aortic valve insufficiency.
Clinical and demographic baseline characteristics and routine preoperative hemodynamic variables were collected from the medical records and existing preoperative trans-thoracic echocardiography (TTE), transesophageal echocardiography (TEE), and left/right cardiac catheterization database.  The ELI value was calculated using the formula (AVA * ASTJ / (ASTJ − AVA)) / (body surface area in M2), where AVA is the aortic valve area and ASTJ is the aortic area at the sinotubular junction 5. The AVA for the native valves were the values obtained by TTE before the TAVR procedure. The EOA replaced this value for any individual implanted with TAVR in postoperative TTE exams. Prosthetic aortic valve characteristics, including the prosthesis diameter, height, bovine/porcine-derived, trans-femoral/apical/aortic implantation, and sheath size, were obtained by reviewing the manufacturer manual.