Bicuspid aortic valve
Encyclopedia
A bicuspid aortic valve (BAV) is most commonly a congenital condition of the aortic valve
where two of the aortic valvular leaflets fuse during development resulting in a valve that is bicuspid instead of the normal tricuspid configuration. Normally the only cardiac valve that is bicuspid is the mitral valve
(bicuspid valve) which is situated between the left atrium
and left ventricle
. Cardiac valves play a crucial role in ensuring the unidirectional flow of blood from the atrium to the ventricles, or the ventricle to the aorta or pulmonary trunk.
Bicuspid aortic valve is an inheritable condition, with a demonstrated association with Notch 1. Both familial clustering and isolated valve defects have been documented. The incidence of bicuspid aortic valve can be as high as 10% in families affected with the valve problem. 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.
s. If the leaflets do not close correctly, aortic regurgitation
can occur. If these become severe enough, they may require heart surgery. 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. The heart is put under more stress in order to either pump more blood through a stenotic valve or attempt to circulate regurgitation blood through a leaking valve.
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
(EchoCG) or magnetic resonance imaging
(MRI).
Most patients with bicuspid aortic valve whose valve becomes dysfunctional will need careful follow-up and potentially valve replacement at some point in life. Regular EchoCG and MRI may be performed. For diagnosed patients, genetic testing is done to allow for future offspring with the disease to be monitored and treated early in life.
Patients with bicuspid aortic valve should be followed by cardiologist or cardiac surgeon with specific interest in this valve pathology.
Average lifespan is similar to that of those without the anomaly.
The extracellular matrix of the aorta in patients with BAV shows marked deviations from that of the normal tricuspid aortic valve.
It is currently believed that an increase in the ratio of MMP2 (Matrix Metalloproteinases 2) to TIMP1 (Tissue Inhibitor Metalloproteinases 1) 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 work-up. 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.
Co-arctation of the aorta (a congenital narrowing in the region of the ductus arteriosus) has also been associated with BAV.
Aortic valve
The aortic valve is one of the valves of the heart. It is normally tricuspid , although in 1% of the population it is found to be congenitally bicuspid . It lies between the left ventricle and the aorta....
where two of the aortic valvular leaflets fuse during development resulting in a valve that is bicuspid instead of the normal tricuspid configuration. Normally the only cardiac valve that is bicuspid is the mitral valve
Mitral valve
The mitral valve is a dual-flap valve in the heart that lies between the left atrium and the left ventricle...
(bicuspid valve) which is situated between the left atrium
Left atrium
The left atrium is one of the four chambers in the human heart. It receives oxygenated blood from the pulmonary veins, and pumps it into the left ventricle, via the mitral valve.-Foramen ovale:...
and left ventricle
Left ventricle
The left ventricle is one of four chambers in the human heart. It receives oxygenated blood from the left atrium via the mitral valve, and pumps it into the aorta via the aortic valve.-Shape:...
. Cardiac valves play a crucial role in ensuring the unidirectional flow of blood from the atrium to the ventricles, or the ventricle to the aorta or pulmonary trunk.
Incidence/prevalence
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 an inheritable condition, with a demonstrated association with Notch 1. Both familial clustering and isolated valve defects have been documented. The incidence of bicuspid aortic valve can be as high as 10% in families affected with the valve problem. 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.
Presentation
In many cases, a bicuspid aortic valve will cause no problems. However BAV may become calcified later in life, which may lead to varying degrees of severity of aortic stenosis that will manifest as murmurHeart murmur
Murmurs are extra heart sounds that are produced as a result of turbulent blood flow that is sufficient to produce audible noise. Most murmurs can only be heard with the assistance of a stethoscope ....
s. If the leaflets do not close correctly, aortic regurgitation
Aortic insufficiency
Aortic insufficiency , also known as aortic regurgitation , is the leaking of the aortic valve of the heart that causes blood to flow in the reverse direction during ventricular diastole, from the aorta into the left ventricle....
can occur. If these become severe enough, they may require heart surgery. 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. The heart is put under more stress in order to either pump more blood through a stenotic valve or attempt to circulate regurgitation blood through a leaking valve.
Diagnosis, treatment, and prognosis
The condition can be associated with a heart murmurHeart murmur
Murmurs are extra heart sounds that are produced as a result of turbulent blood flow that is sufficient to produce audible noise. Most murmurs can only be heard with the assistance of a stethoscope ....
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
Echocardiography
An echocardiogram, often referred to in the medical community as a cardiac ECHO or simply an ECHO, is a sonogram of the heart . Also known as a cardiac ultrasound, it uses standard ultrasound techniques to image two-dimensional slices of the heart...
(EchoCG) or magnetic resonance imaging
Magnetic resonance imaging
Magnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
(MRI).
Most patients with bicuspid aortic valve whose valve becomes dysfunctional will need careful follow-up and potentially valve replacement at some point in life. Regular EchoCG and MRI may be performed. For diagnosed patients, genetic testing is done to allow for future offspring with the disease to be monitored and treated early in life.
Patients with bicuspid aortic valve should be followed by cardiologist or cardiac surgeon with specific interest in this valve pathology.
Average lifespan is similar to that of those without the anomaly.
Aorta complications
One of the most notable associations with BAV is the tendency for these patients to present with ascending aortic aneurysmal lesions.The extracellular matrix of the aorta in patients with BAV shows marked deviations from that of the normal tricuspid aortic valve.
It is currently believed that an increase in the ratio of MMP2 (Matrix Metalloproteinases 2) to TIMP1 (Tissue Inhibitor Metalloproteinases 1) 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 work-up. 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.
Co-arctation of the aorta (a congenital narrowing in the region of the ductus arteriosus) has also been associated with BAV.