A paravalvular leak is a complication that can arise after heart valve replacement surgery. It involves an abnormal flow of blood around, rather than through, the newly implanted prosthetic heart valve.
What is a Paravalvular Leak?
A paravalvular leak, also known as paravalvular regurgitation, describes the leakage of blood that occurs between the prosthetic heart valve and the native heart tissue. Instead of blood flowing through the valve’s opening, it seeps through a gap around the valve’s sewing ring. This gap results from an incomplete seal between the artificial valve and the natural heart structures.
Paravalvular leaks can affect any of the heart’s four valves after replacement surgery: the aortic, mitral, tricuspid, or pulmonary valves. They are most commonly observed in the mitral and aortic valve positions. Mitral leaks are three times more common than aortic leaks, and their incidence can increase after repeat operations.
Causes and Risk Factors
Paravalvular leaks primarily stem from issues related to heart valve replacement surgery. A common cause is incomplete apposition, or fitting, of the prosthetic valve’s sewing ring to the native heart tissue. This can happen if sutures become loose or pull through the natural heart tissue, especially in areas with significant calcium deposits.
Tissue friability, where the heart tissue is unusually delicate, can also prevent a tight seal. Infections, specifically infective endocarditis, are another factor, as they can weaken the tissue around the valve or lead to abscesses that disrupt the seal. Pre-existing calcification in the annular ring can also hinder proper seating and expansion of the prosthetic valve, leading to gaps. Patients who have undergone multiple valve replacement surgeries are at a higher risk.
Identifying Symptoms
Symptoms of a paravalvular leak can vary in presentation and severity. Small leaks might not cause noticeable symptoms, or they may present as a heart murmur detected during a routine examination. Larger leaks can lead to issues due to the heart’s reduced efficiency.
Common symptoms include shortness of breath, particularly with physical activity or when lying flat. Patients may also experience fatigue, weakness, or heart palpitations. Signs of heart failure, such as unexpected weight gain or swelling in the feet and legs, can also occur. Anemia is another possible symptom, resulting from the destruction of red blood cells caused by blood leaking through the defect, known as hemolysis.
Diagnosis Methods
Diagnosing a paravalvular leak and assessing its severity requires specialized imaging. Echocardiography is the primary imaging modality for detection. A transthoracic echocardiogram (TTE) is the initial test, providing an ultrasound scan of the heart.
For a more detailed assessment, a transesophageal echocardiogram (TEE) is employed. During a TEE, a small probe is guided down the esophagus, allowing for higher-resolution images of the heart and precise visualization of the leak’s location and size. Three-dimensional (3D) TEE offers superior diagnostic accuracy, especially for complex or multiple defects, by providing a better definition of the leak’s size and shape. Cardiac computed tomography (CT) scans can also provide additional information. Cardiac catheterization may also be used to further evaluate the leak.
Treatment Options
Managing a paravalvular leak depends on its size, location, the presence and severity of symptoms, and the patient’s overall health. Small, asymptomatic leaks often do not require intervention and may be managed conservatively with regular monitoring. For patients experiencing symptoms, initial management may involve medications to alleviate issues like heart failure, such as diuretics to reduce fluid retention, or blood transfusions for severe anemia caused by hemolysis.
When intervention is needed, two primary approaches are considered: transcatheter repair and surgical re-operation. Transcatheter repair is a minimally invasive procedure where a closure device, often a “plug,” is guided through a catheter, typically inserted via the femoral artery, to block the leak. This method is increasingly favored for high-surgical-risk patients and has shown good immediate and midterm results, with procedural success rates around 90% in experienced centers. While transcatheter closure is associated with lower short-term mortality rates compared to surgery, it may have higher rates of residual moderate-to-severe leaks at follow-up.
Surgical re-operation involves open-heart surgery to either repair the leak with sutures or a patch, or to replace the prosthetic valve entirely. This has historically been the standard treatment for symptomatic leaks, particularly for very large defects, active infection, or valve instability. However, repeat surgeries carry increased risks of complications and mortality, with rates potentially increasing with each subsequent operation. The choice between these treatment options is made by a multidisciplinary heart team, considering the specific characteristics of the leak and the patient’s individual circumstances.