Progression of Ascending Aorta Diameters in Bicuspid Aortic Valve After Transcatheter or Surgical Replacement.

Overview

The goal of this prospective, non-randomized, single-center, observational study is to assess whether there is a progressive dilation of ascending aorta after surgical or transcatheter aortic valve replacement (TAVR) in patients who underwent elective aortic valve replacement or TAVR for stenotic bicuspid aortic valve (BAV) at our institution from 2015 to June 2022. Participants will undergo both a CT and an echocardiographic assessment at least 90 days after surgery.

Bicuspid aortic valve (BAV) is the most common congenital heart defect in adults, affecting 1.3% of the population worldwide. Although valve dysfunction is the most common complication of a bicuspid aortic valve, there is evidence of association of BAV with a specific disease pathology involving the aorta called bicuspid aortopathy. This condition has been proved to predispose to dilatation of all the segments of the proximal aorta both on a genetic and a hemodynamic base, with a reported prevalence of approximately 50% of patients with BAV. Aortic dissection is therefore the most feared complication of BAV aortopathy and BAV itself, but despite a higher relative risk that increases with age, the absolute incidence of aortic dissection remains low. In elderly population the prevalence of BAV seems to be relatively high as well (incidence of 22% in a reported cohort of octogenarian patients). In the era of transcatheter aortic valve replacement (TAVR), the knowledge of BAV incidence in the elderly is extremely important, assuming that this condition has been considered for years a contraindication to percutaneous procedure by the most. Nevertheless, TAVR has been proved to be a feasible and safe procedure in specific patients deemed at high surgical risk. As BAV dysfunction tends to reveal earlier than tricuspid ones, when patients are referred to surgery for aortic valve replacement, ascending aorta is often still normal-sized, not deserving surgical treatment, according to current guidelines. It remains controversial whether there is need for concomitant aortic surgery among patients with BAV dysfunction and moderately-dilated aorta, as some authors reported progressive aortic dilatation and aortic dissection even after AVR. So far, it has never been investigated and there is no information regarding possible differences in the rate of aneurysmal progression in patients with bicuspid aortic valve undergoing surgical or percutaneous aortic valve replacement. A follow-up Computed Tomography (CT) scan is therefore indicated in these patients as chest CT scan is the gold standard for the exact measurement of the aortic diameters. Aim of this prospective, non-randomized observational study is to assess whether there is a progressive dilation of ascending aorta after surgical or transcatheter aortic valve replacement using CT and echocardiographic imaging in patients with a stenotic BAV who undergo surgical or transcatheter aortic valve replacement. At the moment no data are available to formulate any hypothesis. Based on our selection criteria a sample size of 150 will be considered in this study, 60% submitted to a surgical approach and 40% to a transcatheter replacement. This sample size is able to detect, in term of effect size, a difference in diameters changes between the 2 procedures from baseline to approximatively 90 days after procedure of about 0.45, considering a significance level of 5% and a power of 80%.