Differences in Flow-Gradient Patterns Between Severe Bicuspid Aortic Stenosis and Severe Tricuspid Aortic Stenosis　― Mechanistic Insight From Multimodal Imaging ―

Abstract

Background: We investigated the flow-gradient pattern characteristics and associated factors in severe bicuspid aortic stenosis (AS) compared with severe tricuspid AS. Methods and Results: A total of 252 patients with severe AS (115 bicuspid vs. 137 tricuspid) who underwent aortic valve (AV) replacement were retrospectively analyzed. Patients were classified into 4 groups according to stroke volume index and mean pressure gradient across the AV [normal-flow-high-gradient (NF-HG), low-flow-high-gradient, normal-flow-low-gradient, low-flow-lowgradient (LF-LG)]. In 89 patients who underwent cardiac computed tomography (CT), influential structural parameters of the left ventricular outflow tract (LVOT), AV and ascending aorta were assessed. Bicuspid AS was more likely to present a NF-HG pattern (83.5% vs. 64.2%, P<0.001), and significantly fewer presented a LF-LG pattern compared with tricuspid AS. In bicuspid AS, there was a significant mismatch between geometric orifice area (GOA) on CT planimetry and effective orifice area (EOA) calculated using the echocardiographic continuity equation. Bicuspid AS presented with a larger angle between the LVOT-AV and aorta. Multivariate analysis of bicuspid AS revealed that systemic arterial compliance (β=-0.350, P=0.031) and the LVOT-AV-aorta angle (β=-0.538, P=0.001), and stroke volume index (β=0.409, P=0.008) were associated with a discrepancy between GOA and EOA. Conclusions: Flow-gradient patterns in bicuspid AS differ from those of tricuspid AS and are associated with the structural and functional characteristics of the aorta.

Temporal Trends in Diagnosis, Treatments, and Outcomes in Patients With Bicuspid Aortic Valve

“…Recently, MDCT has been used as a complement to echocardiography for diagnosing heart valve disease and preoperative evaluation ( 18 , 29 , 30 ). In patients with BAV, MDCT can provide accurate information about the BAV and adjacent structural abnormalities including the aorta, concomitant anomalies, or combined coronary artery disease ( 10 , 11 ). Furthermore, in the era of transcatheter AVR, the use of multimodal imaging is becoming an increasingly essential part of routine clinical practice, particularly for BAV patients with significant AS ( 10 , 31 ).…”

“…In addition, BAV often is accompanied by aortopathy, other congenital defects, cardiomyopathies, or infective endocarditis (IE) (7)(8)(9). In the past two decades, echocardiographic surveillance of asymptomatic subjects has increased, and multimodality imaging has been developed and applied in heart valve diseases (10,11). Recently, transcatheter aortic valve replacement (AVR) has been expanded to young age and low risk groups, and treatment methods in BAV patients have diversified (12)(13)(14).…”

Assessment of aortic valve area on cardiac computed tomography in symptomatic bicuspid aortic stenosis: Utility and differences from Doppler echocardiography

“…Standard measurements were performed according to current guidelines (12). Bicuspid AV was diagnosed when only two cusps were unequivocally identified in systole and diastole in the short-axis view, as previously described (8,9,13). In all patients, bicuspid AV was confirmed on cardiac CT and echocardiography.…”

“…In particular, the discrepancy between EOA Echo and GOA CT is greater in patients with bicuspid AS compared with those with tricuspid AS (3,8). Previous studies have shown different flow gradient patterns, greater jet eccentricity, and less pressure recovery in patients with bicuspid AS (3,8). However, data to determine the utility of GOA CT on assessment for AS severity are scarce, and there are no studies focusing on bicuspid AS.…”

Echocardiographic assessment of aortic stenosis: a practical guideline from the British Society of Echocardiography

“…Differing classifications of BAV have been advocated in the literature, which means that comparisons and nomenclature are not standardized ( 14 , 15 , 16 , 17 ). Importantly, there is no consensus as to associations between the sub-type of BAV and the pattern of valve dysfunction or aortic dilatation ( 14 , 15 , 16 ).…”