Chest Radiation: Another Sweet Spot for Transcatheter Aortic Valve Replacement

T he growth of transcatheter aortic valve replacement (TAVR) for the management of severe aortic stenosis continues to expand. This procedure was initially approved in 2011 for use in inoperable patients. Through careful study, TAVR has subsequently been evaluated in high-risk, intermediate-risk, and, finally, low-risk patients, although approval for use has not yet been granted for the latter category. Because study and/or approval of TAVR now encompasses patients across the entire risk spectrum, the role of surgical aortic valve replacement (SAVR) needs to be reevaluated. It is currently appropriate to consider SAVR for patients who require another surgical procedure in addition to aortic valve replacement. Examples would be complex multivessel coronary artery disease that requires coronary artery bypass grafting or an ascending aortic aneurysm that requires aortic root replacement. However, multivessel coronary artery disease with a low SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) score (ie, focal stenoses) can be treated with percutaneous coronary intervention with good result. Among young patients (eg, <59 years) who require aortic valve replacement and can tolerate anticoagulation therapy, the choice of a durable mechanical valve may be appropriate. However, a proportion of young patients are not appropriate for anticoagulation therapy for a variety of reasons; therefore, a tissue valve will still need to be considered. In these patients, it is debatable whether a surgical valve with a proven long-term track record would be preferred instead of a transcatheter valve with more limited follow-up data. Although transcatheter valves are thought to have better hemodynamics and a lower incidence of patient prosthesis mismatch than surgical valves, the PARTNER 3 (Placement of Aortic Transcatheter Valve) low-risk trial found that surgical valves were associated with a slightly lower mean aortic gradient and a slightly larger aortic valve area at 30 days and 1 year compared with transcatheter valves. Potential acute and long-term concerns that need to be considered with a transcatheter valve in a young patient include (1) valve deterioration, (2) paravalvular aortic regurgitation, and (3) need for a permanent pacemaker. Regarding the first issue, there has been some concern about TAVR leaflet thrombosis; however, to date, with intermediate follow-up, this does not appear to be a significant clinical problem. With current-generation devices, the rate of moderate to severe aortic regurgitation is quite low in a tricuspid aortic valve (0.8% with a balloon-expandable valve and 3.5% with a self-expanding valve). The need for a permanent pacemaker is also low for a balloon-expandable valve (6.5%) but remains high for a self-expanding valve (17.4%). Bicuspid aortic valves are frequently encountered among younger patients. These valves are often associated with higher eccentricity, extreme annular calcification, calcified raphe, and large size, which can increase the risk of moderate to severe paravalvular aortic regurgitation and thus compromise the long-term efficacy of valve replacement. Adverse valve characteristics can also increase the risk of annular rupture. Bicuspid aortic valves have been associated with more frequent conversion to surgery and lower device success. Early generation balloon-expandable valves (eg, Sapien XT; Edwards Lifesciences) have been associated with higher rates of annular rupture and aortic root injury, whereas early generation self-expanding valves (ie, CoreValve; Medtronic) have been associated with higher rates of second valve implantation and moderate to severe paravalvular leak in bicuspid aortic versus tricuspid aortic valves. However, no difference in these outcomes has been observed for bicuspid versus tricuspid valves with new-generation valves. Accordingly, a careful assessment of the bicuspid valve/ annular complex by TAVR-protocol computed tomography and echocardiography is mandatory among patients with a The opinions expressed in this article are not necessarily those of the editors or of the American Heart Association. From the Department of Medicine, University of Florida, Gainesville, FL. Correspondence to: Anthony A. Bavry, MD, MPH, North Florida/South Georgia Veterans Health System (Malcom Randall Veterans Administration Medical Center), Medical Service, Cardiology Section (111D), 1601 SW Archer Road, Gainesville, FL 32608. E-mail: anthony.bavry@va.gov J Am Heart Assoc. 2019;8:e012783. DOI: 10.1161/JAHA.119.012783. a 2019 The Author. Published on behalf of the American Heart Association, Inc., by Wiley. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.