Tricuspid stenosis (TS) is a condition where the opening of the tricuspid valve in the heart becomes narrowed. This valve is located between the right atrium, which receives deoxygenated blood from the body, and the right ventricle, which pumps blood to the lungs. The narrowing impedes the normal flow of blood from the atrium to the ventricle during the heart’s filling phase (diastole). This resistance causes blood to back up into the right atrium, increasing pressure within the chamber. This elevated pressure ultimately affects the flow of blood returning from the rest of the body.
Primary Causes of Tricuspid Stenosis
The most frequent cause of tricuspid stenosis is rheumatic heart disease, particularly in a global context. This condition develops as a delayed complication from an untreated infection with Group A Streptococcus bacteria, such as strep throat. The body’s immune response mistakenly attacks the heart tissue, leading to inflammation and subsequent fusion or thickening of the valve leaflets, which restricts their opening.
While rheumatic fever remains the dominant cause, other less common etiologies contribute to tricuspid valve narrowing. Carcinoid syndrome, caused by slow-growing tumors that release potent chemicals, can lead to the formation of fibrotic plaques on the valve leaflets. These plaques cause the valve to become rigid and fixed in a narrowed position.
Congenital heart defects are a rare source, where the valve may be malformed from birth. Iatrogenic causes, stemming from medical procedures, also exist, such as damage from repeated endomyocardial biopsies or the presence of multiple pacemaker leads passing through the valve. Infective endocarditis, a serious infection of the heart lining and valves, can also cause relative stenosis if large infected masses (vegetations) obstruct the valve orifice.
How Symptoms Manifest
The symptoms of tricuspid stenosis arise directly from the mechanical obstruction and the resulting backup of blood into the venous system. The narrowed valve prevents the right ventricle from filling adequately, causing blood pressure in the veins leading into the heart to increase significantly. This elevated pressure, known as systemic venous congestion, is the primary driver of patient discomfort.
A common manifestation is peripheral edema (swelling), particularly in the lower extremities and the abdomen. The increased pressure forces fluid out of the vessels and into the surrounding tissues, causing fluid retention. Patients may also experience abdominal discomfort or pain in the upper right quadrant due to the congestion and enlargement of the liver.
Another visible sign of increased pressure is jugular venous distention (JVD), where the neck veins appear prominent and pulsating. The inability of the right side of the heart to move blood forward reduces the filling of the left side, leading to lowered overall cardiac output. This deficit in blood flow results in generalized fatigue and weakness, especially during physical activity.
Diagnostic Procedures and Treatment Approaches
Diagnosis relies predominantly on imaging techniques that allow direct visualization of the valve and measurement of blood flow dynamics. The echocardiogram (ECHO) is the non-invasive tool of choice, utilizing sound waves to create detailed pictures of the heart’s structure and function. This test reveals the thickened, restricted movement of the tricuspid valve leaflets and the enlargement of the right atrium.
The ECHO employs Doppler technology to measure the pressure difference, or gradient, across the narrowed valve. Severe tricuspid stenosis is indicated by a mean diastolic pressure gradient greater than 5 millimeters of mercury, or a calculated valve area less than 1.0 square centimeter. Supporting diagnostic tools, such as an electrocardiogram (ECG), may show signs of right atrial enlargement or heart rhythm abnormalities like atrial fibrillation. A chest X-ray can sometimes indicate an enlarged heart border corresponding to the dilated right atrium.
Treatment strategies are divided between medical management to alleviate symptoms and interventional procedures to address the underlying mechanical defect. Medical therapy is aimed at managing the fluid overload that results from venous congestion. Diuretics are a mainstay of treatment, working to increase the excretion of salt and water through the kidneys, thereby reducing fluid volume and systemic pressure.
In cases of severe stenosis, or when the patient is undergoing surgery for other heart valves, a definitive intervention is required. Surgical approaches include valve repair, which is preferred when the valve structure allows, or valve replacement with a biological (tissue) or mechanical prosthesis. Biological valves are often favored in the tricuspid position due to a lower risk of blood clot formation compared to mechanical valves.
A less invasive option for certain patients is balloon valvotomy. This procedure involves guiding a catheter with a balloon to the valve and inflating it to widen the opening. This percutaneous approach is reserved for patients with favorable valve anatomy or those considered high-risk for open-heart surgery.