Transcatheter aortic valve implantation (TAVI) has become a widely accepted strategy for the treatment of aortic stenosis in patients at intermediate, high, or prohibitive surgical risk. After >1 decade of innovation and clinical trial experience, the available technology for TAVI has grown enormously, and now includes a myriad of vascular access approaches and innovative valve designs. As a result, the range of patients who can benefit from these advances continues to grow rapidly. Furthermore, given the improved safety profile and clinical success of current-generation devices in randomized trials, the use of TAVI among even low-risk populations is justified in current trials. With the rapid dissemination and expansion of this technology, operators need to have a comprehensive understanding of how to select the appropriate procedural approach for each individual patient. In this Review, we detail the current evidence for TAVI among different patient populations, discuss the different vascular access approaches currently in use, and explore differences in design features among currently available and investigational valve systems. Furthermore, we provide an overview of important considerations for special patient populations, such as those with existing mitral prostheses, bicuspid aortic stenosis, isolated aortic regurgitation, or severe left ventricular outflow tract calcification.