P6472Novel cardiac imaging prognostic markers of clinical outcome in patients with bicuspid aortic valve and chronic aortic regurgitation

Abstract

Abstract Background Patients with chronic aortic regurgitation (AR) can have a substantial myocardial damage despite being asymptomatic. Early surgical strategy might be beneficial. Bicuspid aortic valve (BAV) is a congenital heart disease present in almost 30% of these patients. Purpose Identify novel imaging predictors of early disease progression. Methods Prospective three-centre study of patients with chronic AR of at least moderate to severe (3+) grade and BAV morphology. Patients without currently recognised indication for surgical treatment were enrolled. Baseline examination included echocardiography (ECHO) with 3-dimensional (3D) vena contracta area and magnetic resonance (MR) with regurgitant fraction measured from flow sequence. All imaging studies were analysed in CoreLab. The primary endpoint was defined as a combination of cardiovascular death, surgical treatment or hospitalization for heart failure. Results A total of 83 patients with BAV and at least 3+ AR were enrolled during 2015–2018. Median follow-up was 759±455 days, primary composite endpoint occurred in 13 patients who met criteria for surgical treatment, no patient died or was hospitalized for heart failure. Baseline parameters were compared between two groups: patients with and without endpoint. Clinical and laboratory data did not differ between the two groups. Left ventricular (LV) ejection fraction was normal in all patients. LV diameters and volumes were significantly larger in patients with primary endpoint. This was most pronounced in MR measured indexed volumes in end-diastole and end-systole, P=0.003 and P=0.003. Non-invasive markers of diffuse myocardial fibrosis (native T1 relaxation time and global longitudinal strain, P=0.614 and P=0.137 respectively) were not different. Novel markers of AR severity were significantly increased in surgically treated patients: 3D vena contracta 0.26±0.10 cm2 versus 0.38±0.11 cm2 (P<0.001), MR regurgitant fraction 33.9±15.4 versus 50.2±12.2% (P=0.001). Both 3D vena contracta with cutoff value ≥0.4 cm2 (sensitivity=85%, specificity=84%, area under the curve=0.85) and MR regurgitant fraction with cutoff value ≥34% (sensitivity=94%, specificity=58%, area under the curve=0.76) showed high accuracy to identify patients who require early surgical intervention. Adding 3D vena contracta and MR regurgitant fraction to indexed LV end-systolic volumetric parameters significantly increases the predictive value for early disease progression with p=0.001 and p=0.006 (Likelihood-ratio test). 3D vena contracta predictive value Conclusions Novel imaging parameters of AR severity such as 3D vena contracta and MR derived regurgitant fraction predict early disease progression in patients with BAV and at least 3+ chronic AR. These values significantly increase the predictive value of traditional parameters based on LV size measures.