Elsevier

International Journal of Cardiology

Volume 317, 15 October 2020, Pages 144-151
International Journal of Cardiology

Supra-annular sizing of transcatheter aortic valve prostheses in raphe-type bicuspid aortic valve disease: the LIRA method

https://doi.org/10.1016/j.ijcard.2020.05.076Get rights and content

Highlights

  • THV prostheses anchoring occurs at the LIRA plane in raphe-type BAV disease.

  • Supra-annular prosthesis sizing is not standardized in BAV disease.

  • The LIRA sizing method appeared to be safe with a high device success.

  • The LIRA method might optimize prosthesis sizing in raphe-type BAV disease.

Abstract

Background

Recent evidence shows that THV prostheses anchoring occurs at the raphe-level, known as LIRA plane, in raphe-type bicuspid aortic valve (BAV) disease. The purpose of this study was to evaluate the application of a novel supra-annular sizing method, known as Level of Implantation at the RAphe (LIRA) method, to optimize transcatheter heart valve (THV) prosthesis sizing in raphe-type BAV disease.

Methods and results

The LIRA method was applied to all consecutive patients with raphe-type BAV disease between November 2018 to January 2020 in our centre. THV prostheses were sized on the basis of baseline CT scan perimeters at the LIRA plane and at the virtual basal ring. In case of discrepancy between the two plane measurements, the plane with the smallest perimeter was considered the reference for prosthesis sizing. Post-procedural device success, defined according to Valve Academic Research Consortium–2 (VARC-2) criteria, was evaluated in the overall cohort. 20 patients (mean patient age 81 ± 5.4 years, 70% males) were identified as having a raphe-type BAV disease at pre-procedural CT scans and were implanted with different types of THV prostheses. The LIRA plane method appeared to be highly successful (100% VARC-2 device success) with no procedural mortality, no valve migration, no moderate-severe paravalvular leak and low transprosthetic gradient (residual mean gradient of 8.2 ± 2.9 mm Hg).

Conclusions

Supra-annular sizing according to the LIRA method appeared to be safe with a high device success. The application of the LIRA method might optimize THV prosthesis sizing in patients with raphe-type BAV disease.

Introduction

Transcatheter aortic valve implantation (TAVI) is a valid option for the treatment of severe aortic stenosis as an alternative to surgical aortic valve replacement [1,2]. Latest evidences show that TAVI can be offered to patients with low surgical risk, therefore, shifting to a younger population [3]. In this cohort, the prevalence of bicuspid aortic valve (BAV) anatomy is higher [4,5]. However, a small proportion of patients with BAV anatomy may present the disease at advanced age. The prevalence of octogenrerians and nonagenerians in the BAV population varies from 4,5% to 28% [6]. In this specific subgroup of patients TAVI might be a valid option for the treatment of severe aortic stenosis due to a higher risk of surgical complications related to age, frailty, and other comorbidities. BAV anatomy is characterized by heavily calcified leaflets, commisural fusions, calcific or fibrotic raphes, slit-like elliptical orifices and it is also associated with a greater aortic angulation and ascending aorta dimensions compared with tricuspid aortic valve patients [7]. These anatomical aspects have raised the risk of suboptimal results in first-generation devices due to a high rate of paravalvular leak (PVL), device underexpansion, need for a second transcatheter heart valve (THV), aortic dissection and annular rupture [8]. Latest retrospective registries show that the device success rate has improved with the introduction of new-generation THVs [9,10]. However, a higher rate of procedural complications and clinical events is still maintained in the BAV cohort. A retrospective analysis of the Transcatheter Valve Therapy (TVT) registry that included only 3rd generation balloon-expandable Sapien 3 devices (Edwards Lifesciences, Irvine, California,USA) found a higher rate of 30-day of stroke, annular rupture and conversion to open surgery in the bicuspid vs tricuspid cohort [11]. A recent restrospective analysis from the same registry including both balloon and self-expandable devices (81% new generation devices with a majority of balloon-expandable THVs), confirms the improvement of device success and the reduction of moderate-severe aortic insufficiency with new-generation devices, leading to slightly inferior procedural results in bicuspid vs tricuspid TAVI procedures [12]. Particularly, current generation self-expanding prostheses were the minority of devices implanted in this registry analysis and they were associated with a three times higher incidence of post-procedural moderate-severe aortic insufficiency when compared with balloon-expandable prostheses. According to these results, TAVI might represent a valid alternative to cardiac surgery in BAV anatomy, where surgical aortic valve replacement (SAVR) is the reference treatment due to its optimal results and the exclusion of BAV anatomy from randomized clinical studies evaluating TAVI vs SAVR [[1], [2], [3],13]. However, procedural and device success in BAV anatomy still need to be improved with all types of THVs prostheses.

Appropriate prosthesis size selection is essential for a high device success in TAVI in order to optimize the interference between the prosthesis and the anatomy [14]. BAV represents a challenge for an adequate prosthesis sizing due to its anatomical peculiarities [8,9,15,16]. Particularly, the narrowest part of the aortic root in BAV anatomy seems across the aortic valve leaflets instead of the annular virtual basal ring (VBR) [17]. However, even if largely accepted, this concept has not been reproducibly demonstrated and specific measurements to assess the supra-annular level are not standardized across different operators.

A recent multicentre computed tomography (CT) scan study has identified a supra-annular plane that predicts THV prosthesis-anchoring in raphe-type BAV disease, named as LIRA (Level of Implantation at the RAphe) plane [18]. The main objective of our study is to evaluate the safety of a novel supra-annular sizing method to optimize prosthesis sizing in raphe-type BAV disease by performing sizing measurements at the LIRA plane (the LIRA sizing method).

Section snippets

Study design and population

The LIRA sizing method was applied to all consecutive patients treated with TAVI for aortic stenosis in raphe-type BAV disease between November 2018 to January 2020 using different types of THV prostheses. BAV was defined as a deformed aortic valve with 2 functional cusps forming a valve mechanism with <3 zones of parallel apposition. The LIRA sizing method was applied to BAV type 1 and 2 according to Sievers classification; type 1 identified valve morphologies with one raphe, and type 2 was

Baseline characteristics

Between November 2018 and January 2020, a total of 20 patients were included. Mean age was 81 ± 5.4 years, 70% were males with a median Society of Thoracic Surgeons (STS) predicted risk of mortality score of 4.3 (3.0–6.5). Baseline characteristics of the included cohort are reported in Table 2. CT scans identified three different BAV anatomies: 15 patients with type 1 BAV and calcific raphe, 2 patients with type 1 BAV and fibrotic raphe and 3 patients with type 2 BAV. VBR perimeter

Discussion

The main findings of our study are the following:

  • 1)

    THV prosthesis sizing according to the LIRA method appeared to be safe with a high device success in a cohort of 20 patients with raphe-type BAV disease;

  • 2)

    The application of the LIRA method might optimize THV prosthesis sizing in patients with raphe-type BAV disease;

  • 3)

    Tracing the internal borders of the leaflets to obtain the perimeter at the LIRA plane could predict the perimeter occupied by the prosthetic valve;

  • 4)

    Two commissures were visibles in <50%

Limitations

There are several limitations in our study. First, this was a single-centre non-randomized study. Second, TTE measurements were not performed by a core laboratory for the diagnosis of BAV and for the evaluation of echocardiographic outcomes.Third, our proposed sizing methodology (LIRA method) needs to be validated in a larger prospective multicentre registry.

Conclusions

Supra-annular sizing according to the LIRA method in raphe-type BAV patients seems safe with a high device success with different types of THV prostheses. Further larger studies are needed to confirm our preliminary findings.

Declaration of Competing Interest

Matteo Montorfano serves as proctor for Boston Scientific. The other authors have nothing to disclose.

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    All authors take responsibility for all aspects of the reliability and freedom from bias of the data presented and their discussed interpretation.

    1

    Both authors contributed equally to this manuscript.

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