Comprehensive MR Analysis of Cardiac Function, Aortic Hemodynamics and Left Ventricular Strain in Pediatric Cohort with Isolated Bicuspid Aortic Valve

Abstract

Bicuspid aortic valve (BAV) disease demonstrates a range of clinical presentations and complications. We aim to use cardiac MRI (CMR) to evaluate left ventricular (LV) parameters, myocardial strain and aortic hemodynamics in pediatric BAV patients with and without aortic stenosis (AS) or regurgitation (AR) compared to tricuspid aortic valve (TAV) controls. We identified 58 pediatric BAV patients without additional cardiovascular pathology and 25 healthy TAV controls (15.3 ± 2.2years) who underwent CMR with 4D flow. BAV cohort included subgroups with no valvulopathy (n = 13, 14.3 ± 4.7 years), isolated AS (n = 19, 14.5 ± 4.0 years), mixed valve disease (AS + AR) (n = 13, 17.1 ± 3.2 years), and prior valvotomy/valvuloplasty (n = 13, 13.9 ± 3.2 years). CMR data included LV volumetric and mass indices, myocardial strain and aortic hemodynamics. BAV patients with no valvulopathy or isolated AS had similar LV parameters to controls excepting cardiac output (p < 0.05). AS + AR and post-surgical patients had abnormal LV volumetric and mass indices (p < 0.01). Post-surgical patients had decreased global longitudinal strain (p = 0.02); other subgroups had comparable strain to controls. Patients with valvulopathy demonstrated elevated velocity and wall shear stress (WSS) in the ascending aorta (AAo) and arch (p < 0.01), while those without valve dysfunction had only elevated AAo velocity (p = 0.03). Across the cohort, elevated AAo velocity and WSS correlated to higher LV mass (p < 0.01), and abnormal hemodynamics correlated to decreased strain rates (p < 0.045). Pediatric BAV patients demonstrate abnormalities in LV parameters as a function of valvular dysfunction, most significantly in children with AS + AR or prior valvotomy/valvuloplasty. Correlations between aortic hemodynamics, LV mass and strain suggest valvular dysfunction could drive LV remodeling. Multiparametric CMR assessment in pediatric BAV may help stratify risk for cardiac remodeling and dysfunction.