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The secret of the bileaflet heart valve: Why is it present at birth?
Of the many forms of heart disease, bicuspid aortic valve (BAV) is the most common and occurs during fetal development when the two valves of the aortic valve fuse, resulting in a double A bicuspid heart valve instead of the normal three-valve (tricuspid) structure. This heart disease is present at birth and affects approximately 1.3% of the adult population, forming part of the health risks. This article will discuss the physiology of bileaflet heart valves, associated complications, and subsequent preventive and therapeutic measures.
Characteristics of bileaflet heart valve
Normally, heart valves play a key role in controlling the direction of blood flow. However, bileaflet heart valves are functionally limited due to structural defects. Most people with bileaflet heart valves experience no significant problems in daily life, but as they age, they may begin to experience fatigue, especially when performing activities that require endurance, primarily due to compromised heart function. Impaired effects.
Analysis of complications
Calcification phenomenon
Calcification of bileaflet heart valves may occur with age, which can lead to varying degrees of aortic stenosis and produce heart murmurs.
In addition, if the valve does not close completely, aortic regurgitation may occur, which may require heart surgery if severe enough. The increased pressure on the heart caused by bileaflet heart valves may increase the risk of aortic rupture.
Aortic disease
Patients with bicuspid heart valve disease often have aneurysmal lesions of the ascending aorta. The extracellular matrix of the aorta is significantly different from that of a normal three-valve heart valve, and studies have found that the decrease in Fibrillin-1 is closely related to this. The real cause may be an imbalance of certain enzymes (such as MMP2) and inhibitors (such as TIMP1), leading to abnormal degradation of the valve matrix.
Aortic stenosis
In addition to calcification, bileaflet heart valves may cause aortic stenosis, which prevents the normal flow of blood. If the valve does not close tightly, blood may flow backward into the left ventricle. At the same time, congenital stenosis of the thoracic aorta is also associated with bileaflet heart valves.
Pathophysiology of bileaflet heart valve
During development, the two valves of the aortic valve often fuse. About 80% of the cases involve right coronary and left coronary valve fusion, while about 17% of cases involve right coronary and non-coronary valve fusion, and the rest only account for 2%. This pattern of fusion predicts the risk of future complications in those with the disease.
Hemodynamics
Analysis of hemodynamics of the ventricular system can predict subsequent complications. Patients with bileaflet heart valves have higher blood flow rates and a spiral shape as measured by 4D MRI, which causes the aorta to suffer greater damage when blood flows, showing their special human physiology.
Diagnosis and testing
The diagnosis of a bicuspid heart valve is usually confirmed by a heart murmur (usually heard in the right second intercostal space) and a blood pressure difference between the upper and lower extremities with an ultrasound of the heart, such as an echocardiogram or 4D MRI. . Advances in 4D MRI allow doctors to accurately visualize the characteristics and patterns of blood flow in the heart.
Treatment methods
When faced with complications caused by cardiac structural problems, the treatment of choice is usually surgical intervention, such as aortic valve replacement or balloon valve dilatation. These measures will help reduce the likelihood of significant health risks.
Prognosis and efficacy
Research shows that more than one-third of patients with bileaflet heart valves may suffer major complications, including aortic stenosis and aortic regurgitation. For patients whose aorta is dilated, cardiac ultrasound examinations should be performed annually to monitor the progression of the disease.
In general, bileaflet heart valve, as the most common heart valve abnormality, has a profound impact on the quality of life of patients. Faced with this phenomenon, we can't help but think: Why can this structural abnormality persist into old age in some people without causing other larger problems?
