Tricuspid Stenosis

Tricuspid valve dysfunction can result from morphological alterations in the valve or from functional aberrations of the myocardium. Tricuspid stenosis is almost always rheumatic in origin and is generally accompanied by mitral and aortic valve involvement.[1]

Most stenotic tricuspid valves are associated with clinical evidence of regurgitation that can be documented by performing a physical examination (murmur), echocardiography, or angiography. Stenotic tricuspid valves are always anatomically abnormal, and the cause is limited to a few conditions. With the exceptions of congenital causes or active infective endocarditis, tricuspid stenosis takes years to develop.[2, 3]

Tricuspid Stenosis. A representation of a stenotic tricuspid valve. This image demonstrates fusion of the commissures (shown as dotted lines).

Tricuspid stenosis results from alterations in the structure of the tricuspid valve that precipitate inadequate excursion of the valve leaflets. The most common etiology is rheumatic fever, and tricuspid valve involvement occurs universally with mitral and aortic valve involvement. With rheumatic tricuspid stenosis, the valve leaflets become thickened and sclerotic as the chordae tendineae become shortened. The restricted valve opening hampers blood flow into the right ventricle and, subsequently, to the pulmonary vasculature. Right atrial enlargement is observed as a consequence. The obstructed venous return results in hepatic enlargement, decreased pulmonary blood flow, and peripheral edema. Other rare causes of tricuspid stenosis include carcinoid syndrome, endocarditis, endomyocardial fibrosis, systemic lupus erythematosus, and congenital tricuspid atresia.[2, 3, 4]

In the rare instances of congenital tricuspid stenosis, the valve leaflets may manifest various forms of deformity, which can include deformed leaflets, deformed chordae, and displacement of the entire valve apparatus. Other cardiac anomalies are usually present.[1]

At least four conditions can cause obstruction of the native tricuspid valve. These include (1) rheumatic heart disease, (2) congenital abnormalities, (3) metabolic or enzymatic abnormalities, and (4) active infective endocarditis. Note the following:

• Rheumatic tricuspid stenosis: In this entity, diffuse thickening of the leaflets occurs, with or without fusion of the commissures. The chordae tendineae may be thickened and shortened. Calcification of the valve rarely occurs. The leaflet tissue is composed of dense collagen and elastic fibers that produce a major distortion of the normal leaflet layers.

• Carcinoid heart disease: Carcinoid valve lesions characteristically manifest as fibrous white plaques located on the valvular and mural endocardium. The valve leaflets are thickened, rigid, and reduced in area. Fibrous tissue proliferation is present on the atrial and ventricular surfaces of the valve structure.

• Congenital tricuspid stenosis: These lesions are observed more commonly in infants. They may manifest as incompletely developed leaflets, shortened or malformed chordae, small annuli, abnormal size and number of the papillary muscles, or any combination of these defects.

• Infective endocarditis: Large infected vegetations obstructing the orifice of the tricuspid valve may produce stenosis. This condition is relatively uncommon, even in those who abuse intravenous drugs.

• Unusual causes: Rare causes of tricuspid stenosis include Fabry disease and giant blood cysts.

• Mimickers of tricuspid stenosis: Several conditions may mimic tricuspid stenosis by obstructing flow through the valve. These conditions include supravalvular obstruction from congenital diaphragms, intracardiac or extracardiac tumors, thrombosis or emboli, or large endocarditis vegetations. In addition, conditions that impair right-sided filling can produce similar symptoms and physical findings. These conditions include constrictive pericarditis and restrictive cardiomyopathy.

United States data

Tricuspid stenosis is rare, occurring in less than 1% of the population. While found in approximately 15% of patients with rheumatic heart disease at autopsy, it is estimated to be clinically significant in only 5% of these patients. The incidence of the congenital form of the disease is less than 1%.

International data

Tricuspid stenosis is found in approximately 3% of the international population. It is more prevalent in areas with a high incidence of rheumatic fever. The congenital form of the disease is rare and true incidence is not available.

Race-, sex-, and age-related demographics

No racial predisposition is apparent.

Tricuspid stenosis is observed more commonly in women than in men, similar to mitral stenosis of rheumatic origin. The congenital form of the disease has a slightly higher male predominance.

Tricuspid stenosis can present as a congenital lesion or later in life when it is due to some other condition. The congenital form accounts for approximately 0.3% of all congenital heart disease cases. The frequency of tricuspid stenosis in the older population, due to secondary causes, ranges from 0.3-3.2%.

The prognosis is generally good if therapy is provided for tricuspid stenosis. For those cases in which tumors are the cause of the stenosis, the prognosis is directly related to the prognosis of the underlying disease. In those cases of precipitating infection, if the behavior that caused the initial infection (eg, intravenous drug use) can be modified, prognosis for the patient is good.

Morbidity/mortality

The mortality associated with tricuspid stenosis depends on the precipitating cause. The general mortality rate is approximately 5%.

Complications

Complications that can be encountered after tricuspid valve replacement include infection of the prosthetic valve, particularly in those instances when endocarditis was present preoperatively. Tricuspid insufficiency and thromboembolization can also occur.[5]

Educate patients regarding the adverse effects of anticoagulation. Emphasize instructions regarding dental hygiene and subacute bacterial endocarditis prophylaxis for invasive procedures.

Fatigue, due to limited cardiac output, may be present.

Systemic venous congestion leads to abdominal discomfort and swelling. The onset is usually gradual, but it may be rapid if atrial fibrillation or flutter develops. (For related information, see Medscape's Atrial Fibrillation Resource Center).

Dyspnea may be present but is not severe unless concomitant mitral valve disease is present.

Patients may complain about prominent pulsations in the neck.

When tricuspid stenosis occurs concomitantly with mitral stenosis, the decrement of cardiac output to the pulmonary bed may paradoxically diminish the dyspnea, hemoptysis, and orthopnea typically seen with mitral stenosis.

Obtain information regarding preceding rheumatic fever, symptoms of the carcinoid syndrome, and possible congenital abnormalities.

With sinus rhythm (more common with tricuspid stenosis than with mitral stenosis), the jugular venous pulse increases and the A wave is prominent (may be confused with an arterial pulse).

If atrial fibrillation occurs, the A wave is lost.

Peripheral edema and ascites are frequent.

Without significant mitral pathology, the patient should not be dyspneic and can probably lie flat without symptoms.

A prominent right atrium may be palpable to the right of the sternum. If not obscured by mitral stenosis sounds, a tricuspid opening snap may be heard. A diastolic murmur is audible along the left sternal border or at the xiphoid, which increases with inspiration. Often, tricuspid regurgitation is also present, represented by a holosystolic murmur in a similar location.

The first heart sound may be split widely. The second heart sound may be single. This single sound is due to the inaudible closure of the pulmonary valve from the decrease in blood flow through the stenotic tricuspid valve.

The following laboratory studies may be useful:

• Complete blood cell count: If the white blood cell count is elevated, infection should be considered. A disproportionately high hemoglobin (polycythemia) level may be indicative of poor pulmonary blood flow.

• Complete chemistry profile: The results of this test may help delineate metabolic abnormalities associated with certain inborn errors of metabolism.

A complete evaluation of the heart often necessitates a multimodality approach, including radiography, echocardiography, computed tomography (CT), magnetic resonance (MR) imaging, and invasive angiography.[6]

The following imaging studies may be useful:

• Chest radiography: Cardiac size may range from normal to enlarged (ie, cardiomegaly). Right atrial enlargement may be prominent. Findings specific to a particular associated congenital heart disease may also be seen.

• Echocardiography: This test has become the procedure of choice for the diagnosis of valvular disorders. The test results help delineate the structure of the tricuspid valve and any other intracardiac pathology that may contribute to the pathophysiology of the process.[7]

Electrocardiogram

Arrhythmias are frequent in this patient population. Because of the enlargement of the right atrium, the presence of atrial flutter and/or fibrillation should not be surprising. In sinus rhythm, right atrial enlargement or abnormality (tall P waves on inferior leads) may be noted.

Cardiac catheterization

This may be required prior to surgery in older patients to assess for concomitant coronary artery disease. Right heart catheterization can be used to determine the gradient across the valve and valve area (ie, severity of stenosis) and assess the presence of associated congenital defects (eg, septal defects, intracardiac shunts, anomalous veins) if present. Assessment of aortic and mitral valves via left heart catheterization is useful in patients with rheumatic disease.

Most commonly, stenotic tricuspid valves are secondary to rheumatic fever. These generally demonstrate fibrous tissue proliferation without calcium deposits. The leaflet tissue is composed of dense collagen and elastic fibers, producing major distortions of the normal leaflet layers. Congenitally abnormal valves can show a wide spectrum of incompletely developed leaflets, abnormal chordae tendineae, or dysplastic papillary muscles.

In the treatment of tricuspid stenosis, medical care consists of assessment and treatment of the underlying cause of the valvular pathology, as follows:

• Treat bacterial endocarditis with the appropriate antibiotics as determined by the sensitivity of the organisms cultured.

• Medically address cardiac arrhythmias depending on their characterization.

• Decreasing right atrial volume overload with diuresis and salt restriction helps decrease symptoms and improve hepatic function.

Inpatient care consists of treating the underlying precipitating condition. For acute bacterial endocarditis or rheumatic causes, antibiotic therapy is indicated until the acute phase has resolved. Then, valve surgery can be considered, if indicated.

After valve replacement, inpatient care consists of regulating the anticoagulation and treating postoperative arrhythmias until stability has been achieved. After valve replacement, adjust anticoagulation to an international normalized ratio (INR) of 3-4 because of the low-pressure and low-flow state of the right side. Because of the high risk of thrombosis in this low-pressure system, some authors recommend warfarin therapy for bioprosthetic or mechanical valves.

Tricuspid stenosis remains a surgical disease and requires either commissurotomy or replacement of the valve if right heart failure or low cardiac output has resulted. Surgery is rarely performed solely on the tricuspid valve; it is usually performed in combination with mitral and/or aortic valve disease repair. Note the following:

• With tricuspid valve replacement, the risk of thrombosis is significant and many surgeons advise warfarin therapy for either mechanical or bioprosthetic valve placement.

• Percutaneous balloon valvuloplasty has been used successfully, as long as concomitant regurgitation is not significant.[8] Reddy and colleagues report on the successful outcome of percutaneous valvuloplasty to treat severe bioprosthetic tricuspid valve stenosis in the setting of infective endocarditis. Their patient, a 29-year-old male with a history of intravenous drug use and two previous bioprosthetic tricuspid valve placements, was considered extremely high risk for redo valve replacement surgery. The investigators conclude that interventional treatment of prosthetic valvular stenosis in the setting of endocarditis is a reasonable therapy to use when open surgical repair is prohibitively risky with regard to mortality.[9]

• The therapy chosen depends on the structure of the valve and the degree of deformity encountered.

• When possible, excise intracavitary pathology, whether it be tumors or other structural abnormalities.

• Redundant portions of the dilated right atrium can be excised during the same procedure for restoring the atrium back to normal size.

• In selected patients with prior tricuspid valve surgery and significant stenosis of a bioprosthetic tricuspid valve or a right atrium to right ventricle (RA-to–RV) conduit, percutaneous tricuspid valve replacement may be an option.[10]

• Transcatheter valve-in-valve implantation with either the Melody or Edwards SAPIEN valve may be a potential procedure for patients with significant tricuspid stenosis, significant tricuspid regurgitation, or a mixed lesion and a failing bioprosthesis.[11, 12]

Consultation with infectious disease specialists may be appropriate if the stenosis is secondary to an infectious process.

An endocrinologist may be of assistance if carcinoid syndrome or an inborn error of metabolism is the cause of the pathology.

No specific dietary restrictions are necessary before therapy.

Fluid and sodium restriction is prudent if signs of venous congestion are present.

If a valve replacement is undertaken and the patient must be anticoagulated, dietary instructions must be provided regarding those foods that interfere with anticoagulation and are rich in vitamin K.

Activity is usually self-limited by the patient because of easy fatigability secondary to oxygen deprivation.

Once the pathology has been corrected, no activity restrictions are necessary.

For those cases in which intravenous drug use or bacterial endocarditis was the precipitating event, emphasize careful dental hygiene. Maximize drug detoxification efforts. Of course, do not forget that routine antibiotic coverage should be administered for prevention of endocarditis.

Outpatient care consists of routine follow-up care with echocardiography studies to assess valvular function. Check the INR monthly to regulate anticoagulation. In those instances in which the tricuspid stenosis is secondary to some other process (eg, carcinoid, tumor), consider continual surveillance of the underlying disease state.

In 2014, the AHA/ACC released a revision to its 2008 guidelines for management of patients with valvular heart disease (VHD); and ESC/EACTS issued a revision of its 2007 guidelines in 2021.[13, 14]

The AHA/ACC guidelines include the following recommendations for diagnostic testing and initial diagnosis of tricuspid stenosis (TS)[13] :

• Transthoracic echocardiography (TTE) is indicated to assess the anatomy of the valve complex, evaluate severity of stenosis, and characterize any associated regurgitation and/or left-sided valve disease. (Class I; Level of Evidence: C)
• Conaider invasive hemodynamic assessment of severity of TS in symptomatic patients when clinical and noninvasive data are discordant.(Class IIb; Level of Evidence: C)

Both guidelines concur that Class I indications for tricuspid valve surgery are as follows[13, 14] :

• Symptomatic patients with severe tricuspid stenosis
• Patients with severe tricuspid stenosis undergoing left-sided valve intervention

The AHA/ACC guidelines also recommend consideration of percutaneous balloon tricuspid commissurotomy in patients with isolated, symptomatic severe TS without accompanying TR. (Class IIb; Level of Evidence: C)

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Generally, outpatient medications consist of the anticoagulant warfarin and any antiarrhythmic used to treat atrial fibrillation or flutter, if present. Diuretics may be needed depending on the volume status of the patient.

Class Summary

Alter the electrophysiologic mechanisms responsible for arrhythmia.

Digoxin (Lanoxin)

Cardiac glycoside with direct inotropic effects and indirect effects on the cardiovascular system. Acts directly on cardiac muscle and increases myocardial systolic contractions. Indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.

Class Summary

Used for prophylaxis and treatment of venous thrombosis, pulmonary embolism, and thromboembolic disorders.

Warfarin (Coumadin)

Interferes with hepatic synthesis of vitamin K–dependent coagulation factors. Tailor dose to maintain an INR in the range of 2-3.