Bicuspid aortic valve

In many cases, a bicuspid aortic valve will cause no problems. People with BAV may become tired more easily than those with normal valvular function and have difficulty maintaining stamina for cardio-intensive activities due to poor heart performance caused by stress on the aortic wall. Complications Calcification BAV may become calcified later in life, which may lead to varying degrees of severity of aortic stenosis that will manifest as murmurs. If the leaflets do not close correctly, aortic regurgitation can occur. The extracellular matrix of the aorta in patients with BAV shows marked deviations from that of the normal tricuspid aortic valve, specifically reduced Fibrillin-1. It is currently believed that an increase in the ratio of MMP2 (Matrix Metalloproteinases 2) to TIMP1 (tissue inhibitors of metalloproteinase) may be responsible for the abnormal degradation of the valve matrix and therefore lead to aortic dissection and aneurysm. However, other studies have also shown MMP9 involvement with no differences in TIMP expression. The size of the proximal aorta should be evaluated carefully during the workup. The initial diameter of the aorta should be noted and annual evaluation with CT scan, or MRI to avoid ionizing radiation, should be recommended to the patient; the examination should be conducted more frequently if a change in aortic diameter is seen. From this monitoring, the type of surgery that should be offered to the patient can be determined based on the change in size of the aorta. Aortic narrowing A bicuspid aortic valve may cause the heart's aortic valve to narrow (aortic stenosis). Coarctation of the aorta (a congenital narrowing in the region of the ductus arteriosus) has also been associated with BAV. ==Pathophysiology==

Fusion of aortic valve leaflets occurs most commonly (≈80%) between the right coronary and left coronary leaflets (RL), which are the anterior leaflets of the aortic valve. However, all fusion patterns associate with a specific area or areas of dilated enlargement in either the root of the ascending aorta, the ascending aorta, or the transverse aortic arch. Hemodynamics Identifying hemodynamic patterns in the aorta after left ventricle systole aids in predicting consequential complications of bicuspid aortic valve. ==Diagnosis==

A bicuspid aortic valve can be associated with a heart murmur located at the right second intercostal space. Often there will be differences in blood pressures between upper and lower extremities. The diagnosis can be assisted with echocardiography or magnetic resonance imaging (MRI). Four-dimensional magnetic resonance imaging (4D MRI) is a technique that defines blood flow characteristics and patterns throughout the vessels, across valves, and in compartments of the heart. Four-dimensional imaging enables accurate visualizations of blood flow patterns in a three-dimensional (3D) spatial volume, as well as in a fourth temporal dimension. • "Real" bicuspid valves with two symmetric leaflets • A tricuspid architecture with a fusion of two leaflets • A tricuspid architecture with a fusion of three leaflets == Treatment ==

Complications stemming from structural heart issues are most often treated through surgical intervention, which could include aortic valve replacement, or balloon valvuloplasty. ==Prognosis==

BAV leads to significant complications in over one-third of affected individuals. Notable complications of BAV include narrowing of the aortic valve opening, backward blood flow at the aortic valve, dilation of the ascending aorta, and infection of the heart valve. If aortic regurgitation and dilation of the ascending aorta are noted in someone, they should undergo yearly surveillance with transthoracic echocardiograms if the aortic root measures 4.5 centimeters or greater in diameter. ==Epidemiology==

Bicuspid aortic valves are the most common cardiac valvular anomaly, occurring in 1–2% of the general population. It is twice as common in males as in females. Bicuspid aortic valve is a heritable condition, with a demonstrated association with mutations in the NOTCH1 gene. Its heritability (h^2) is as high as 89%. Both familial clustering and isolated valve defects have been documented. Recent studies suggest that BAV is an autosomal dominant condition with incomplete penetrance. Other congenital heart defects are associated with bicuspid aortic valve at various frequencies, including coarctation of the aorta. Bicuspid aortic valve abnormality is also the most observed cardiac defect in Turner syndrome. ==References==