Tricuspid stenosis overview

# Overview
Tricuspid stenosis (TS) is a type of valvular heart disease where there is a narrowing of the orifice of the tricuspid valve of the heart. A majority of stenotic tricuspid valves are associated with evidence of  tricuspid regurgitation. Tricuspid stenosis is quite uncommon in developed countries due to the low prevalence of rheumatic heart disease, which is the commonest cause of TS. It is the least common valvular stenosis lesion, and generally accompanies mitral and/or aortic valve involvement. It is extremely rare to have isolated acquired tricuspid stenosis. Rheumatic tricuspid valve disease seldom receives much attention and can be easily overlooked on routine clinical and echocardiographic examination, which may lead to postoperative problems after successfully relieving left-sided valvular disease. The clinical findings associated with rheumatic mitral valve disease are also more severe than that of rheumatic tricuspid valve disease, making it rather easy to miss the diagnosis of concomitant tricuspid stenosis (TS). There is a paucity of literature on the prevalence and management of rheumatic tricuspid valve disease. Most of the literature on rheumatic tricuspid stenosis is old, which may be reflective of the low prevalence of rheumatic heart disease in developed countries. However, developing countries and the Indian subcontinent still have a significant prevalence of rheumatic tricuspid valve disease, occurring mostly in young women. Stenotic tricuspid valves are usually anatomically abnormal, and often take years to develop, with few exceptions such as congenital causes, active endocarditis.

# Classification
Tricuspid stenosis is staged based on the valve anatomy and hemodynamics, and the hemodynamic consequences.

# Pathophysiology
TS is characterized by structural changes in the tricuspid valve. The pathophysiology of tricuspid valve stenosis depends on the underlying etiology. In rheumatic heart disease which is the most common cause of TS, there is diffuse scarring and fibrosis of the valve leaflets, fusion of the commissures, and shortening of the chordae tendineae as a result of inflammation. These abnormalities limit leaflet mobility and reduce the size of the tricuspid orifice, increasing the transtricuspid diastolic gradient, which can eventually result in systemic venous hypertension and congestion.
The pathophysiology of tricuspid stenosis based on the underlying etiology:
- Rheumatic tricuspid stenosis:
Diffuse scarring and fibrosis of the valve leaflets from inflammation. Fusion of the commissures may or may not occur.
Chordae tendineae may become thickened and shortened.
As a result of the dense collagen and elastic fibers that make up leaflet tissue, the normal leaflet layers become significantly distorted.
- Diffuse scarring and fibrosis of the valve leaflets from inflammation. Fusion of the commissures may or may not occur.
- Chordae tendineae may become thickened and shortened.
- As a result of the dense collagen and elastic fibers that make up leaflet tissue, the normal leaflet layers become significantly distorted.
- Carcinoid heart disease:
Fibrous white plaques located on the valvular and mural endocardium are characteristic presentations of carcinoid valve lesions.
Valve leaflets become thick, rigid and smaller in area.
Atrial and ventricular surfaces of the valve structure contain fibrous tissue proliferation.
- Fibrous white plaques located on the valvular and mural endocardium are characteristic presentations of carcinoid valve lesions.
- Valve leaflets become thick, rigid and smaller in area.
- Atrial and ventricular surfaces of the valve structure contain fibrous tissue proliferation.
- Congenital tricuspid stenosis:
More common in infants
Lesions may present in a number of different ways, either singularly or in any combination of the following:
Incompletely developed leaflets
Shortened or malformed chordae
Small annuli
Papillary muscles of abnormal size and number
- More common in infants
- Lesions may present in a number of different ways, either singularly or in any combination of the following:
Incompletely developed leaflets
Shortened or malformed chordae
Small annuli
Papillary muscles of abnormal size and number
- Incompletely developed leaflets
- Shortened or malformed chordae
- Small annuli
- Papillary muscles of abnormal size and number
- Mechanical obstruction of flow through the tricuspid valve:
Supravalvular obstruction from congenital diaphragms
Intracardiac or extracardiac tumors
Thrombosis or emboli
Large endocarditis vegetations
- Supravalvular obstruction from congenital diaphragms
- Intracardiac or extracardiac tumors
- Thrombosis or emboli
- Large endocarditis vegetations

# Causes
The most common cause of TS is rheumatic heart disease.  Other causes of TS include carcinoid syndrome, congenital abnormalities, endocarditis, lupus, and mechanical obstruction by a tumor.

## Common Causes
- Rheumatic heart disease (majority of the cases)
- Carcinoid syndrome
- Congenital
Etiology of tricuspid stenosis in operatively excised valves in patients >15years

## Causes by Organ System

## Causes by Alphabetical Order
- Amyloidosis
- Carcinoid syndrome
- Cardiac tumor/Thrombus
- Congenital heart disease
- Ebstein's anomaly
- Endomyocardial fibrosis
- Fabry disease
- Giant blood cyst
- Infective endocarditis
- Intravenous leiomyomatous tumor
- Metastatic tumor
- Myxoma
- Pacemaker infection
- Pacemaker leads
- Rheumatic heart disease
- Systemic lupus erythematosus
- Whipple's disease

# Differential Diagnosis
The differential diagnosis of tricuspid stenosis includes valvular abnormalities causing a similar clinical presentation, and other causes of systemic venous congestion. The heart murmur of tricuspid stenosis must be differentiated from that of other valvular diseases. However, it should be noted that tricuspid stenosis often co-exists with other valvular pathologies such as tricuspid regurgitation, mitral valve and aortic valve abnormalities. Tricuspid stenosis is characterized by a mid diastolic murmur best heard over the left sternal border. It has a rumbling character, a tricuspid opening snap with the wide splitting of S1. The differential diagnosis of tricuspid stenosis includes:
- Aortic regurgitation: The diastolic murmur of aortic regurgitation decreases with respiration, which is in contrast to that of tricuspid stenosis.
- Mitral regurgitation: The murmur of mitral regurgitation is blowing, soft and best heard at the apex.
- Mitral stenosis: The murmur of mitral stenosis is mid-diastolic, rumbling, and best heard after the opening snap.
- Tricuspid regurgitation: The murmur of tricuspid regurgitation is blowing, holosystolic, and best heard over the fourth intercostal area at the left sternal border.
Tricuspid stenosis should also be differentiated from diseases causing a similar clinical presentation, such as:
- Tricuspid atresia
- Constrictive pericarditis
- Restrictive cardiomyopathy
- Atrial myxoma

# Epidemiology and Demographics
TS is the least common valvular disease. TS is rarely an isolated disease, it is mostly associated with mitral and/or aortic valve abnormalities with/without concomitant tricuspid regurgitation.

### Prevalence
A prospective study of the echocardiographic profile of tricuspid valve disease in 788 patients with rheumatic heart disease in India was done. 9% of the patients had tricuspid valve disease and half of these patients with tricuspid valve disease had tricuspid stenosis with/without tricuspid regurgitation. The prevalence of TS is lower in developed countries compared to the developing countries due to the low prevalence of rheumatic heart disease.

### Gender
Most patients with rheumatic tricuspid stenosis are young women with mitral and/or aortic valve disease.

# Risk Factors
One of the most recognized risk factors for TS is rheumatic fever.

# Natural History, Complications, and Prognosis

### Natural history
The natural course of tricuspid stenosis is not well defined. It is extremely rare for TS to occur in isolation, it is usually associated with existing mitral valve disease with/without concomitant tricuspid regurgitation. The most common cause of TS is rheumatic heart disease and it is usually associated with coexisting mitral valve and/or aortic valve abnormality. TS of rheumatic etiology usually occurs with tricuspid regurgitation. Tricuspid stenosis often takes years to develop, with  some exceptions such as congenital causes and active infective endocarditis. Complications of tricuspid stenosis include heart failure, liver failure, and stroke.

### Complications of TS
- Right atrial enlargement
- Atrial fibrillation
- Heart failure
- Infective endocarditis
- Cerebrovascular accident
- Liver failure

### Prognosis
With medical intervention, severe tricuspid stenosis appears well tolerated over several years of follow-up.

# Diagnosis

## History and Symptoms
Tricuspid stenosis is mostly associated with mitral valve abnormalities. Common symptoms include dyspnea, peripheral edema, and fatigue.

## Signs and Symptoms
- Fatigue
- Dyspnea
- Abdominal discomfort (due to hepatomegaly secondary to systemic venous congestion)
- Pedal edema
- Jugular venous distension
- Heart murmur

## Physical Examination
Tricuspid stenosis often co-exists with mitral stenosis, thus depending on the severity of mitral valve pathology, symptoms differ. The diagnosis of TS may also be missed when they coexist. Patients can lay flat without any symptoms in the absence of serious mitral valve pathology and thus, not present with any signs of dyspnea. Characteristic findings of TS include an opening snap and a low to medium pitch diastolic rumbling murmur, usually localized to the lower left sternal border (fourth intercostal space) with inspiratory accentuation.

## Echocardiogram
Transthoracic echocardiography (TTE) should be performed among patients with suspected TS to confirm the diagnosis, determine the etiology, and establish the baseline severity. TTE commonly reveals findings associated with other valvular diseases, such as tricuspid regurgitation and/or mitral stenosis. TS is mainly characterized by an elevated transvalvular gradient. TTE helps in the determination of the anatomic and hemodynamic characteristics of the tricuspid valve. TTE allows the detection of the following:
- Tricuspid valve thickening and calcification
- Chordal thickening and calcification
- Decreased valve mobility with diastolic doming
- Reduced leaflet separation at peak opening
- Immobility of the leaflets ('frozen' appearance seen in carcinoid syndrome)
- Atrial tumors or metastatic lesions
- Valvular  vegetations (suggestive of infective endocarditis)
- Right atrial ball valve thrombus
Doppler echocardiography: The evaluation of the severity of tricuspid stenosis is primarily done using the hemodynamic information provided by continuous-wave Doppler (CWD). Doppler echocardiography is useful to assess the severity of TS through the evaluation of the transvalvular gradient (the hallmark of a stenotic valve is an increase in transvalvular velocity recorded by CWD). The assessment of the tricuspid valve area is limited by the common association of TS with tricuspid regurgitation. The coexistence of tricuspid regurgitation causes the underestimation of the tricuspid valvular area.  A tricuspid valve area  < 1.0 cm2 is associated with increased severity of the TS.

## Findings Associated with Increased Severity
TTE findings that are associated with increased severity of tricuspid stenosis include:
- Mean pressure gradient >5 mm Hg,
- Pressure half-time >190 milliseconds
- Tricuspid valve area  < 1.0 cm2
- Enlargement of the right atrium
- Dilation of the inferior vena cava

# 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary

## Electrocardiogram
The electrocardiogram of patients with TS can demonstrate a sinus rhythm with or without right atrial hypertrophy. Patients with TS experience frequent arrhythmias, particularly atrial flutter and/or atrial fibrillation due to the enlargement of the right atrium. EKG findings suggestive of coexisting mitral valve disease can also be seen.

## Chest X ray
The chest X-ray in a patient with tricuspid stenosis may show right atrial enlargement. The heart size can range from a normal-sized heart to cardiomegaly, with additional findings suggestive of coexisting valvular pathology such as mitral stenosis.

## Cardiac MRI
While echocardiography remains the diagnostic imaging modality of choice, cardiac MRI is useful to evaluate tricuspid stenosis when the results of the echocardiography are insufficient.

# ACC/AHA Guidelines- ACCF/ACR/AHA/NASCI/SCMR 2010 Expert Consensus Document on Cardiovascular Magnetic Resonance (DO NOT EDIT)

## Cardiac Catheterization
While echocardiography remains the diagnostic imaging modality of choice, cardiac catheterization is useful to evaluate tricuspid stenosis when the results of the non-invasive testing are insufficient, particularly among patients who are being evaluated for other conditions such as mitral stenosis and pulmonary hypertension. In the older pre-surgery population, cardiac catheterization may be necessary in order to assess concomitant artery disease.
Catheterization of the right heart is useful for the evaluation of:
- The gradient across the tricuspid valve
- Associated congenital defects
Catheterization of the left heart is useful for the assessment of hemodynamic changes related to the aortic and mitral valves in patients with rheumatic heart disease.

# 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary

# Treatment

## Medical Therapy
Medical therapy with diuretics and sodium restriction for patients with TS with systemic venous congestion. Patients with TS should receive medical therapy for left heart failure, and/or pulmonary hypertension if they are present. Treatment of the underlying etiology and associated conditions/complications is necessary. Fibrinolytic therapy is the first line therapy for prosthetic tricuspid valve thrombosis resulting in tricuspid stenosis.

## Surgery
Tricuspid valve surgery is recommended for patients undergoing surgical intervention for left valvular disease as well as among patients with severe symptomatic isolated TS. Tricuspid valve balloon valvuloplasty has a limited efficacy in the management of tricuspid stenosis.

# 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: Executive Summary