TAVR
What Is the Best Treatment for Severe Aortic Stenosis Patients With Small Aortic Annulus?
2021 年 85 巻 7 号 p. 977-978
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2021 年 85 巻 7 号 p. 977-978
Small aortic annulus (SAA) is still a challenge in both surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR) for aortic stenosis (AS) patients. SAA has been shown to be associated with poorer outcomes after SAVR, with increased mortality and ischemic cardiovascular events, compared with normal-sized aortic annulus.1 SAA has been known to cause prosthesis-patient mismatch (PPM), which is associated with less left ventricular (LV) mass regression, increased heart failure rehospitalization, structural valve deterioration, and late mortalities after AVR.2 In this issue of the Journal, Meguro et al report several important findings regarding TAVR for AS patients with SAA based on an analysis of data from the Japan Transcatheter Valve Therapies registry.3 Meguro et al show that SAA is associated with less hemodynamic improvement and is an independent predictor of PPM compared with normal-sized annulus.3 They also report that patients who received a 20-mm intra-annular device had a smaller indexed effective orifice area (iEOA) than those receiving a 23-mm supra-annular device (median [interquartile range] 0.94 [0.78–1.06] vs. 1.07 [0.8–1.24] cm2/m2, respectively; P=0.001).3 Previous studies reported similar findings,4 and TAVR has been shown to result in better hemodynamics and a lower incidence of PPM than SAVR in randomized controlled studies.5,6 These findings may have led to the idea that TAVR with a supra-annular device is the best choice for AS patients with SAA. However, in real-world practice, decision making is not that simple, and the selection of treatments and prostheses should be based on many factors. Herein, we discuss how to choose the best treatment for each AS patient with SAA (Figure).
Algorithm for treatment selection for severe aortic stenosis (AS) with small aortic annulus. ARE, aortic root enlargement; AVR, aortic valve replacement; PPM, patient prosthesis mismatch; SAVR, surgical aortic valve replacement; TAVR, transcatheter aortic valve replacement. *Choice of the intra-annular value is reasonable if the anatomy is not feasible for a supra-annular value.
Article p 967
First, the occurrence and grade of PPM need to be predicted. For surgical aortic prosthetic valves, a predicted effective orifice area (EOA) chart is available,7 and the iEOA can be calculated by dividing the predicted EOA by body surface area. For transcatheter heart valves, several studies have published the mean EOA of each size of each prosthesis.3,8
Second, it is essential to assess whether PPM would affect the outcomes in each patient with SAA. Based on a large dataset including >60,000 cases, Herrmann et al showed that severe PPM is an independent predictor of 1-year mortality after TAVR, whereas moderate PPM is not.9 Mohty et al reported that severe PPM does not increase late mortality after SAVR in old (age ≥70 years) or obese patients, and that moderate PPM increases late mortality after SAVR in patients with LV dysfunction.10 Paradoxical low-flow severe AS has been shown as another factor indicating vulnerability to PPM.11
Third, the standard treatment method is selected on the basis of guidelines and heart team discussions.12 Given the effectiveness of SAVR with the sutureless valve or aortic root enlargement (ARE) on EOA, SAA alone should not be the rationale for changing the treatment plan from SAVR to TAVR, especially in low-risk patients. Instead, if the TAVR candidate patient is expected to have significant PPM and is at a reasonable risk of surgery, we reconsider SAVR with ARE.
Fourth, detailed procedural planning is important in patients with SAA. In TAVR, based on previously published hemodynamic data, the supra-annular device would be the primary choice for patients who are expected to have significant PPM.3,4 If the anatomy is not feasible for the supra-annular device, it is reasonable to choose an intra-annular device. If patients are not expected to have significant PPM, the prosthesis should be chosen based on other anatomical characteristics and the heart team’s preference. In SAVR, the sutureless valve has been reported to be hemodynamically advantageous over conventional stented valves.13 Shurestha et al reported that the mean (±SD) EOA of the smallest sutureless valve, which covers 19- to 21-mm aortic annuli, was 1.40±0.37 cm,13 which is similar to the EOA of the 23-mm supra-annular transcatheter valve.3,8 In addition, ARE is a powerful surgical solution for SAA. A recent meta-analysis revealed that the incidence of PPM was lower in SAVR with ARE than conventional SAVR.14 Unlike other randomized controlled studies, the Placement of Aortic Transcatheter Valves (PARTNER) 3 trial showed similar hemodynamic performance after SAVR and TAVR,15 probably because larger surgical valves were implanted compared with other trials. Importantly, ARE was used in 4.6% of SAVR patients in the PARTNER 3 trial, which is higher than the ARE rate (3.2%) in the Society of Thoracic Surgeons database.2 Although SAVR with ARE has been reported to have longer cardiopulmonary bypass and aortic cross-clamp times than simple SAVR, the rates of reoperation for bleeding and early mortality were reportedly be similar.14 The potential beneficial effect of ARE on future valve-in-valve TAVR is another important point. A larger transcatheter valve can be implanted after SAVR with ARE, and the risk of coronary obstruction at the time of valve-in-valve TAVR should be lower because ARE enlarges not only the annulus, but also the sinus of Valsalva and increases the distance between the prosthesis and coronary ostia. Thus, it is reasonable to choose the sutureless valve or standard valve with ARE for patients who are expected to have significant PPM after simple SAVR with the standard valve.
Avoiding significant PPM after SAVR or TAVR is very important in AS patients. Even for patients with SAA, significant PPM can be avoided by following the step-by-step process described above to determine the best treatment.
M.T. serves as a consultant to Edwards Lifesciences, Terumo, and Century Medical, and has received lecture fees from Medtronic, Abbott, and Livanova. J.I. has no conflicts of interest to declare.
