Year in review: bicuspid aortopathy

Abstract

Purpose of review: This article outlines the key research contribution to bicuspid aortic valve (BAV) aortopathy over the past 18 months.

Recent findings: Investigators have further defined the current gaps in knowledge and the scope of the clinical problem of BAV aortopathy. Support for aggressive resection strategies is waning as evidence mounts to suggest that BAV is not similar to genetic connective tissue disorders with respect to aortic risks. The role of cusp fusion patterns and valve-mediated hemodynamics in disease progression is a major area of discovery. Molecular and cellular mechanisms remain elusive and contradictory.

Summary: BAV aortopathy is a major public health problem that remains poorly understood. New insights on valve-mediated hemodynamics using novel imaging modalities may lead to more individualized resection strategies and improved clinical guidelines.

Figure 1. Recommendations for aortic surgery in patients with BAV aortopathy

From 1998 to 2014, 10 different international guidelines have focused on the aortopathy related to bicuspid aortic valves. Different criteria are used if the patient is undergoing surgery for aortic valve disease (red) or there are no surgical indications for the aortic valve (blue). With permission (pending) from reference #.

Figure 2. 4D flow MRI of BAV-mediated hemodynamics

Images show control and BAV patient with a right-left (RL) and right-noncoronary (RN) fusion pattern. Note that the RL-BAV resulted in a marked eccentric aortic outflow jet (but not higher velocity, arrow) impinging on the aortic wall compared to TAV. We have found that the BAV phenotype (RL vs right-noncoronary [RN]) strongly impacts aortic outflow and thus aortic regions exposed to elevated WSS(50, 61).

Figure 3. Correlation of WSS with tissue histopathology

Eccentric transvalvular BAV flow (left) exposes aortic wall regions exposed to elevated WSS (middle, red region) which exhibit abnormal tissue metrics of aortopathy (right)(71).