Outcomes of Transcatheter Aortic Valve Replacement in Patients With Severe Aortic Stenosis: A Review of a Disruptive Technology in Aortic Valve Surgery.

Importance: Medically treated symptomatic severe aortic stenosis has poor outcomes, and in the past 6 decades, it has successfully been treated with surgical aortic valve replacement (SAVR). However, one-third of patients with indications for SAVR are not offered surgery because of the high risk of complications. Transcatheter aortic valve replacement (TAVR), initially developed as a less invasive treatment for inoperable patients, has successfully been used in healthier patient cohorts. In 2017, TAVR became the most common approach for aortic valve replacement in the United States. Observations: During the past decade, the Placement of Aortic Transcatheter Valve (PARTNER) trials (for balloon-expandable valves) and the CoreValve trials (for self-expandable valves) investigated the performance of TAVR in progressively lower-risk patient cohorts. The initial trials demonstrated TAVR to be superior (PARTNER B) and noninferior (CoreValve Extreme Risk) to optimal medical therapy in inoperable patients. Subsequent trials showed both balloon-expandable and self-expandable valves to have good results in high-risk, medium-risk, and low-risk surgical patients when compared with SAVR. However, owing to the fundamentally different nature of the procedure, some complications have been more prevalent with TAVR, most notably moderate or severe paravalvular leak, conduction abnormalities necessitating permanent pacemaker placement, and vascular complications. When present, these complications have been associated with worse outcomes. Conclusions and Relevance: The results of the groundbreaking TAVR trials from the past decade have led to a revolution in the treatment of aortic stenosis. There are now 3 US Food and Drug Administration-approved TAVR devices, and with the encouraging results from the latest low-risk trials, TAVR is likely going to become the dominant treatment for symptomatic severe aortic stenosis. New devices on the horizon are looking to improve the complication rates of TAVR, and ongoing trials are looking to further expand the indications of TAVR and answer 1 of the main remaining questions, ie, long-term durability of percutaneously placed devices.