Tricuspid Valve and Its Function
The heart consists of two main pumping systems: right and left. While the left side pumps oxygenated blood to the body, the right side sends deoxygenated blood returning from the body to the lungs for oxygenation. The tricuspid valve, as its name suggests, is a three-leaflet valve (anterior, posterior, septal) located between the right atrium and the right ventricle.
Its function is to allow deoxygenated blood entering the right atrium to pass into the right ventricle and, when the ventricle contracts, to prevent blood from flowing backward, directing it instead into the pulmonary artery. This valve has a wider annulus and a thinner structure compared to the mitral valve on the left side.
Causes of Tricuspid Valve Diseases
Diseases are divided into two categories based on their origin: congenital or acquired.
Congenital Diseases
These are structural abnormalities that occur during fetal development.
- Ebstein’s Anomaly: This is the most well-known congenital tricuspid valve disorder. The valve leaflets are displaced downward (into the ventricle) from their normal position. This causes a portion of the right ventricle to function like an atrium (atrialization) and the right ventricle to become smaller and dysfunctional. Mild forms may not show symptoms until adulthood.
- Tricuspid Atresia: This is a condition where the valve fails to form at all. There is no passage between the right atrium and the ventricle. For life to be sustained, the baby must have holes in the heart (ASD, VSD) and requires emergency surgery immediately after birth.
Acquired Causes
The vast majority of tricuspid problems seen in adults are due to “secondary” (functional) causes.
- Left Heart Diseases: This is the most common cause. Mitral valve disease or severe left heart failure increases lung pressure (pulmonary hypertension). This high pressure strains the right heart, dilates the right ventricle, and even if the tricuspid valve structure is intact, its annulus widens, preventing the valve from closing properly.
- Pacemaker Leads: Pacemaker leads pass through the right heart and are placed in the ventricle. Sometimes these leads can compress or damage the valve leaflets, leading to regurgitation.
- Endocarditis: This is an infection of the inner lining of the heart. Bacteria can settle on the tricuspid valve, especially in intravenous drug users or patients with central catheters.
- Rheumatic Heart Disease: Although it typically affects the mitral and aortic valves, in advanced cases, it can also affect the tricuspid valve, leading to stenosis.
Difference Between Stenosis and Regurgitation
Valve dysfunction manifests in two ways:
- Tricuspid Regurgitation: This is the most common form. The valve cannot close completely, and blood flows backward into the right atrium instead of the right ventricle. This causes increased pressure in the neck veins and liver.
- Tricuspid Stenosis: This is rarer and usually of rheumatic origin. The valve cannot open completely, making it difficult for blood to pass into the ventricle.
The Body’s Signals: Symptoms
While left heart failure manifests as shortness of breath, right heart failure due to the tricuspid valve is characterized by “systemic circulation” findings:
- Leg Edema: Due to gravity, pitting edema occurs, especially in the ankles and legs.
- Abdominal Swelling (Ascites): As a result of fluid accumulation in the abdominal cavity, patients struggle to fit into their clothes and experience loss of appetite and a feeling of fullness.
- Liver Enlargement: Blood pooling in the liver causes pain and tenderness under the right rib cage. In the long term, it can lead to liver dysfunction known as “cardiac cirrhosis.”
- Prominent Neck Veins: Increased pressure in the right atrium causes the jugular veins in the neck to visibly swell.
- Weakness and Easy Fatigability: Occurs due to decreased pumping capacity of the heart.
Diagnostic Methods
Physical examination and imaging methods are used together for diagnosis.
- Echocardiography (ECHO): This is the gold standard for diagnosis. The valve structure, the degree of regurgitation (mild-moderate-severe), and right ventricular functions are evaluated.
- Transesophageal ECHO (TEE): An ultrasound performed through the esophagus provides a much more detailed view of the valve, which is essential, especially for surgical planning.
- Cardiac MRI: This is the best method for showing the volume and function of the right ventricle. It is particularly guiding in congenital conditions such as Ebstein’s anomaly.
Treatment Options
Tricuspid valve treatment is planned with a multidisciplinary approach based on the cause and severity of the disease.
1. Medical Treatment
Used to alleviate symptoms in mild to moderate regurgitation or in patients unsuitable for surgery. Diuretics reduce edema and abdominal swelling by eliminating excess fluid from the body. However, medications do not correct mechanical valve dysfunction.
2. Surgical Treatment (Repair and Replacement)
In patients undergoing mitral or aortic valve surgery, concomitant intervention is generally recommended if there is moderate-to-severe tricuspid regurgitation or if the valve annulus is dilated. Isolated tricuspid surgery is rarer.
- Tricuspid Valve Repair (Ring Annuloplasty): This is the preferred method. A “C”-shaped synthetic ring is sewn onto the dilated valve annulus to narrow the valve’s diameter and ensure the leaflets meet (coaptation).
- Tricuspid Valve Replacement: If the valve is too damaged to be repaired (e.g., in Ebstein’s anomaly or severe endocarditis), it is replaced. Since blood flow velocity in the right heart is low, the risk of clotting is high; therefore, biological valves, which have a lower clotting risk, are preferred over mechanical valves.
3. Non-Surgical Interventional Methods
In recent years, catheter-based treatments performed via the groin have been developed for patients at high risk for open-heart surgery.
- TriClip: Similar to the clipping technique for the mitral valve, the tricuspid valve leaflets are clipped together edge-to-edge to reduce regurgitation.
- Valve-in-Valve: In patients who previously had a biological valve implanted that has deteriorated, a new valve can be placed non-surgically.
Why Should It Be Treated?
Tricuspid regurgitation should not be underestimated. Severe, untreated regurgitation over a long period leads to:
- Permanent right heart failure,
- Irreversible liver damage (Cirrhosis),
- Kidney dysfunction,
- Treatment-resistant edema and ascites formation.
Early diagnosis and, especially during mitral valve surgeries, proper evaluation and intervention for the tricuspid valve if necessary, are vital for the patient’s long-term quality of life.
