Supra-annular sizing for transcatheter valve implantation in bicuspid aortic stenosis

Introduction

Transcatheter aortic valve implantation (TAVI) is an established treatment option for symptomatic severe aortic stenosis in high [1] and intermediate risk patients [2]. With a prevalence of 1% to 2% in countries outside China, bicuspid aortic valve (BAV) disease is a common congenital malformation [3] that often results in premature aortic stenosis. Since BAV represents a challenge for interventional treatment [4], it traditionally has been considered as a relative contraindication against TAVI. The Lotus valve (Boston Scientific Corp, Marlborough MA) is a mechanically expandable, fully repositionable and retrievable second-generation TAVI prosthesis with an outer adaptive seal that facilitates accurate positioning, early valve function, and hemodynamic stability during deployment, and minimizes paravalvular leakage [5]. Therefore, it might be a good treatment option for BAV stenosis.
For planning TAVI procedures, an in-depth analysis of multidetector computed tomography (MDCT) images is crucial. In most reports of interventional treatment of BAV stenosis, preprocedural measurements were done according to current guidelines [6]. However, such measurements might lead to inaccurate annular sizing and prosthesis selection in BAV disease. Specifically, measurement of the basal ring may lead to the selection of too large prostheses, potentially leading to suboptimal results, or may make the intervention impossible due to non-availability of the necessary large valve sizes.

Aim

Therefore, an alternative process of measurement may be preferred. We therefore aimed to use a new algorithm for MDCT analysis, i.e., supra-annular measurement of the valve opening area at the level of the maximal calcification, to assess the correct aortic valve area opening, and compared it to the conventional analysis algorithm in terms of aortic valve area and diameters in a series of patients with severe BAV stenosis undergoing TAVI using the mechanically expandable Lotus valve.

Material and methods

Between January 2015 and February 2017, patients with severe symptomatic aortic stenosis undergoing TAVI at the University Hospital Basel, Switzerland, were screened for the presence of BAV. Before the intervention, patients underwent transthoracic echocardiography, coronary angiography, and MDCT, and were reviewed by the institutional heart team to determine the best treatment approach. Bicuspid aortic valve patients underwent TAVI...


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