Transcatheter Aortic Valve Replacement

Abstract

T ranscatheter aortic valve replacement (TAVR) is increasingly being adopted in the treatment of severe aortic stenosis since over 250,000 patients have been treated worldwide. The risks of the procedure are decreasing and results appear stable up to 5 years (1-5). Further progress is expected from improvement in patient selection, procedural performance and technology. On this last point a number of reports have shown promising early results with the new generation devices (6-9). This latter point is the topic of the study by Meredith et al. (10) in this issue of JACC: Cardiovascular Interventions, which reports the 1-year outcome of TAVR using the Lotus valve (Boston Scientific, Natick, Massachusetts). Besides showing mid-term outcomes with the newgeneration TAVR devices for the first time, the authors should be congratulated for their rigorous methodology including neurological evaluation, core laboratory analysis of echocardiography, computed tomography, and electrocardiography and adjudication of adverse events using the most recent VARC criteria (11). The study by Meredith et al. (10) shows that the good 30-day results of the Lotus valve (8) are confirmed after 1 year with good hemodynamic performance and very low incidence of paravalvular leaks (88.6% of patients had no/trivial regurgitation), which translates into a good mid-term clinical benefit: 1-year all-cause mortality 10.9%; 3.4% disabling strokes; no repeat procedure, and 97.1% of patients being in New York Heart Association functional class I or II. The good functional results were confirmed by a variety of functional scores and assessment of quality of life. However, a permanent pacemaker implantation was performed in 31.9% of cases.What are the positive aspects and possible concerns raised by these findings when compared with the current knowledge from earlier devices and the preliminary results with the other new devices?The incidence of paravalvular leaks observed here is very low, in line with the results recently presented at an early stage with the other new devices (6,7,9). This represents significant progress in what was a serious limitation of the first-generation devices where moderate-to-severe aortic regurgitation occurred in 9% to 30% of patients with a proven negative impact on outcomes (1)(2)(3)(4)12). This is due to the polymeric outer adaptive seal of the Lotus valve and also to the retrievability and repositioning capacity. The controlled mechanical positioning and retrievable potential are also of interest in cases with challenging anatomy such as borderline height of the coronary ostia. Furthermore, it decreases the need for valve in a valve implantation. This attractive feature is also present in both the Direct Flow (Direct Flow Medical, Santa Rosa, California) and Evolut R (Medtronic, Minneapolis, Minnesota) prostheses (7,9).The excellent hemodynamic performance with low transvalvular gradients and valve area ¼ 1.7 cm 2 is