Background: The potential benefit of using larger or smaller transcatheter heart valves (THV) in patients with borderline aortic annulus measurement (BAM) remains uncertain. The objective of this study was to evaluate the clinical outcomes associated with the selection of larger or smaller THV in the context of BAM. Methods: This was a multicenter observational study including patients who underwent transcatheter aortic valve replacement with the SAPIEN 3 or SAPIEN 3 Ultra-valve systems (Edwards Lifesciences, Irvine, CA) from April 2014 to June 2021. BAM was defined according to the manufacturer sizing chart and included the following annulus areas: 314 to 346, 400 to 430, 500 to 546 mm ² . A 1:1 propensity score matching was used to compare outcomes of patients with larger or smaller THV. Results: From a total of 2467 patients, BAM was identified in 852 patients (34.5%). A larger and smaller THV was selected in 338 (39.7%) and 514 patients (60.3%) patients, respectively. The choice of a larger THV was associated (before and after propensity matching) with a higher risk of new-onset left bundle branch block (HR, 2.25 [95% CI, 1.39–3.65; P =0.001) and permanent pacemaker implantation (HR, 1.86 [95% CI, 1.11–3.09]; P =0.016) without any impact on gradients or the risk of moderate or severe paravalvular regurgitation at discharge (HR, 0.78 [95% CI, 0.41–1.45]; P =0.427). The risk of periprocedural complications such as aortic rupture and tamponade was low (<1%) and similar between groups. Conclusions: In patient with BAM, selecting a larger SAPIEN 3/Ultra THV increased the risk of conduction disturbances without any benefit on valve hemodynamics and clinical outcomes.

Over the past five decades, the Fontan procedure has been developed to improve the life expectancy of patients with congenital heart defects characterized by a functionally single ventricle. The Fontan circulation aims at redirecting systemic venous return to the pulmonary circulation in the absence of an impelling subpulmonary ventricle, which makes this physiology quite fragile and leads to several long-term complications. Despite the importance of hemodynamic assessment through cardiac catheterization in the management and follow-up of these patients, a thorough understanding of the ultimate functioning of this type of circulation is lacking, and the interpretation of the hemodynamic data is often complex. In recent years, new tools such as combined catheterization with cardiopulmonary exercise testing have been incorporated to improve the understanding of the hemodynamic profile of these patients. Furthermore, extensive percutaneous treatment options have been developed, addressing issues ranging from obstructive problems in Fontan pathway and acquired shunts through compensatory collaterals to the percutaneous treatment of lymphatic circulation disorders and transcatheter edge-to-edge repair of atrioventricular valves. The aim of this review is to detail the various tools used in cardiac catheterization for patients with Fontan circulation, analyze different percutaneous treatment strategies, and discuss the latest advancements in this field.