A Bicuspid Aortic Valve (BAV) is the most common congenital heart defect, affecting approximately one to two percent of the population. The aortic valve controls the flow of oxygen-rich blood from the heart’s main pumping chamber into the aorta, the body’s largest artery. When this valve is bicuspid, it has an abnormal structure that can lead to problems over a person’s lifetime. An echocardiogram, often called an echo, is a non-invasive ultrasound of the heart that serves as the primary tool for identifying and assessing the condition. It provides detailed images of the valve’s structure and function, which is necessary for long-term care and management.
Understanding the Bicuspid Aortic Valve
The normal aortic valve, known as a tricuspid valve, consists of three small, crescent-shaped leaflets that open and close to ensure unidirectional blood flow. A bicuspid aortic valve, by contrast, has only two leaflets, or cusps, an anatomical difference that occurs during fetal development. The valve is formed incorrectly, often with two cusps being fused together. The resulting two-leaflet structure can impede the valve’s ability to open and close smoothly, creating turbulent blood flow. While some people live their entire lives without experiencing issues, the abnormal structure makes the valve prone to degeneration over time.
The Role of Echocardiography in Diagnosis
Echocardiography is the standard imaging method used to diagnose a bicuspid aortic valve, allowing doctors to visualize the valve’s structure in real-time. It uses high-frequency sound waves to create moving pictures of the heart’s chambers, valves, and surrounding blood vessels. When the bicuspid valve opens during systole, the two leaflets often create a characteristic visual appearance in the short-axis view, described as a “football” or “fish-mouth” shape. The echo also identifies a raphe, a ridge where the third leaflet failed to fully separate, marking the point of fusion between two cusps. Doppler echocardiography measures the speed and direction of blood flow across the valve to quantify the severity of any functional issues.
Identifying Associated Valve Issues
The primary functional issues associated with a bicuspid aortic valve are Stenosis and Regurgitation. Over time, abnormal mechanical stress leads to accelerated calcification and stiffening, causing the valve opening to narrow (aortic stenosis). This narrowing forces the heart’s main pumping chamber to work harder to push blood through the restricted opening. The echo measures stenosis severity by calculating the mean pressure gradient (the pressure difference across the valve) and the aortic valve area; a high gradient indicates severe narrowing. Aortic regurgitation, or insufficiency, occurs when the two leaflets fail to close completely, allowing blood to leak backward. The echocardiogram assesses regurgitation severity by observing the size and velocity of the backward-flowing jet of blood.
Monitoring and Long-Term Care
A BAV diagnosis requires lifelong surveillance due to the potential for progressive valve dysfunction and associated aortic complications. The echocardiogram establishes a schedule for follow-up imaging, ranging from every one to five years based on the initial severity of valve issues and aortic size. This regular monitoring helps detect subtle changes in function before they cause significant symptoms.
A significant concern in BAV patients is the associated aortopathy, which is a structural abnormality that often leads to the progressive widening, or dilation, of the aorta, particularly the ascending aorta. The echo accurately measures the diameter of the aortic root and the ascending aorta to monitor this enlargement. This dilation is monitored closely because a significantly enlarged aorta carries an increased risk of a life-threatening event like dissection or rupture.
Surgical intervention, such as valve replacement or repair, is considered when the echo confirms severe valve dysfunction or when the aorta reaches a specific size threshold, often 50 millimeters or larger. If the patient is undergoing heart surgery for another reason, the threshold for repairing an enlarged aorta is lowered to 45 millimeters. The goal of long-term care is to maintain normal heart function and prevent aortic complications.