Stenosis of the right cardiac valves: Pulmonary stenosis, Tricuspid Stenosis

Stenosis of the right cardiac valves: Pulmonary stenosis, Tricuspid Stenosis

Pulmonic stenosis

Etiology of pulmonic stenosis (narrowing) is usually congenital (in 95 % of cases). An acquired form of pulmonic stenosis can occur with carcinoid heart disease (it can cause both pulmonic stenosis and pulmonic regurgitation). Rheumatic heart disease is a rare cause of pulmonic stenosis and, when present, it is accompanied by multiple valve disease. Large vegetations on a pulmonic valve infected by endocarditis can be a very rare cause of pulmonary stenosis (or regurgitation).
 Children with pulmonic stenosis are most often asymptomatic and the diagnosis is made by auscultation of the systolic murmur at the region of the pulmonary artery by the pediatrician. (See below) Over the years in patients with a significant degree of pulmonic valve stenosis syncopal episodes, angina-like discomfort in physical effort, effort dyspnea or fatigue may occur. 

In neonates with severe narrowing of the pulmonary valve, cyanosis is often observed due to shunting of blood with a direction from right to left through a patent foramen ovale. This shunt is the result of an elevated pressure in the right atrium. The latter is a consequence of increased pressure in the right ventricle, due to the pulmonary stenosis, which imposes an increased load on right ventricular function. Differential diagnosis of cyanosis in the neonate includes, in addition to severe pulmonary stenosis, with a shunt at the level of the atrial septum, some other congenital anomalies such as transposition of the great arteries or pulmonary atresia.

The systolic murmur of pulmonary stenosis is heard louder parasternally at the second left intercostal space. The murmur has a maximum intensity at the middle of systole. The murmur often is preceded by an ejection click heard at the beginning of systole. The click often is better heard lower parasternally, or at the cardiac apex and not at the position of the maximum intensity of the systolic murmur. Usually, the click is not heard in case of a severe stenosis. There is often a wide splitting of the second heart sound, due to the slower ejection of blood by the right ventricle as a result of pulmonary stenosis.

Indications of severity of pulmonic valve stenosis are the following: a murmur with its maximum intensity occurring late in systole, the longer the duration of the murmur, the greater the splitting of the second heart sound and the lower the intensity of the pulmonic component of the second heart sound, which in some cases of severe stenosis of the pulmonary valve may not be audible.

ECG and echocardiographic findings in pulmonic stenosis

ECG: In moderate to severe pulmonic stenosis, a right QRS axis and ECG findings of right ventricular hypertrophy are observed. In severe stenosis, there may also be an indication of right atrial abnormality or dilatation (tall P waves > 2.5 mm in the inferior leads)
Echocardiography in pulmonic stenosis:
It detects the position of the stenosis. In particular, the stenosis (narrowing) can be valvular, subvalvular, or supravalvular (stenosis of the pulmonary artery).
When the stenosis is valvular, in the left parasternal short axis view at the base of the heart, there is thickening, reduced mobility and a dome-shaped opening of the valve leaflets. When a subvalvular stenosis is present, there is a narrowing caused by excess muscle tissue in the right ventricular outflow tract, and when it is supravalvular, a narrowing of the main pulmonary artery or of one of its main branches is observed (a pathologic narrowing of the arterial lumen causing turbulent flow at the site of the stenosis, detected with color flow doppler).

In general, in pulmonic stenosis with the color doppler, turbulent blood flow is observed with aliasing, i.e. an abrupt change in color with a mosaic color pattern in the area of stenosis, due to increased blood flow velocity.

 The severity of the stenosis is determined by examining blood velocity through the stenosis with continuous wave doppler, which provides the maximum pressure gradient. A pressure gradient is the pressure difference that develops between the two sides of a stenotic valve, i.e. the pressure immediately proximal minus the pressure immediately distal to the stenosis. The patient during the examination should be in a relaxed state, in order to avoid an overestimation of the severity of the stenosis.

 Pulmonary artery magnetic resonance imaging (MRI) or helical CT scan can be used to depict a stenosis of the pulmonary artery or its branches.

Treatment of pulmonary valve stenosis

 The decision for treatment  (with transcutaneous balloon valvuloplasty being preferred over surgical treatment) is made when the peak pressure gradient is > 40 mmHg.
Patients with dysplastic valves may not be suitable for balloon valvuloplasty and may require pulmonary valve replacement with a bioprosthetic valve. Percutaneous stented pulmonary valve
implantation is an alternative to surgical replacement of the  pulmonary valve 
 in selected patients with pulmonic stenosis and regurgitation.

A video of valvular pulmonary stenosis (echocardiogram) by Dr Ramachandra Barik
See Link
An echo case: A patient with severe pulmonary stenosis, right ventricular hypertrophy and right to left shunt through a small ventricular septum defect by Dr. Maged Al Ali

Tricuspid valve stenosis (Tricuspid stenosis)

 It is much rarer than mitral stenosis. It is more frequent in women than in men, but overall it is a very rare condition. Tricuspid valve stenosis is usually due to rheumatic fever. Then it does not occur as a single valve disease but it usually coexists with mitral stenosis and it is often accompanied by some degree of tricuspid regurgitation. Among patients with severe mitral stenosis, hemodynamically significant tricuspid stenosis is present in 5-10%.
Tricuspid stenosis of non-rheumatic etiology is even rarer than stenosis due to rheumatic valve disease.
Such rare causes of tricuspid valve stenosis are carcinoid syndrome (which more often causes tricuspid regurgitation), congenital tricuspid atresia, intramyocardial fibrosis and vegetations on the tricuspid valve due to endocarditis (these usually cause valvular regurgitation and rarely valvular stenosis).

Pathophysiology, symptoms and clinical findings in tricuspid valve stenosis

Tricuspid stenosis causes a diastolic pressure gradient (pressure difference) between the right atrium and the right ventricle, resulting in an elevated pressure in the right atrium and in the systemic veins (systemic venous congestion). The pressure gradient depends on the severity of the stenosis and on the blood flow. It increases on inspiration, in which venous return to the large intrathoracic systemic veins increases and therefore the tricuspid transvalvular blood flow increases. The opposite occurs on expiration. A mean diastolic pressure gradient in the tricuspid valve of ≥ 4 mmHg is usually sufficient to result in an increase in mean right atrial pressure to levels that can cause a degree of systemic venous congestion, but this can be reduced by salt intake limitation and the administration of a diuretic.
 Systemic venous congestion causes peripheral edema (swelling at the lower parts of the body, usually the ankles), hepatomegaly (liver enlargement) and ascites (accumulation of fluid in the abdominal cavity). These are the main manifestations of tricuspid stenosis along with fatigue due to the decreased cardiac output.
However, because mitral stenosis usually precedes the development of tricuspid stenosis, many patients have initial symptoms of effort dyspnea and nocturnal dyspnea, as a result of mitral valve stenosis. Typically, when severe tricuspid stenosis develops, dyspnea decreases and is relatively mild compared to the severity of symptoms and signs of systemic venous congestion (edema, ascites, and hepatomegaly).
In tricuspid stenosis, the jugular veins are distended (jugular venous distention on the neck)  and if heart rhythm is sinus ( thus if atrial contraction occurs), very tall a- waves are observed in the jugular pulse. This is the result of an elevated pressure in the right atrium at atrial systole, because the stenotic valve creates an obstacle to blood flow into the right ventricle. Also in the jugular pulse, there is a slow y -descent (negative wave), because emptying of blood from the right atrium to the right ventricle is delayed by the stenotic valve. In severe tricuspid valve stenosis, severe hepatic congestion may result in some cases in the development of cirrhosis of the liver, with jaundice, muscle wasting, large ascites, and splenomegaly.
The diastolic murmur (diastolic rumble) of tricuspid stenosis has some similarities to the diastolic murmur of mitral stenosis. Because mitral valve stenosis usually coexists, the murmur of tricuspid stenosis may not be detected by the examining physician. The diastolic murmur of tricuspid stenosis is usually heard better on the left lower sternal border and on the xiphoid area. Its intensity increases during inspiration. In expiration and during the stress phase of the Valsalva maneuver its intensity decreases (because then the venous blood return to the right atrium and flow through the tricuspid valve decreases).

The ECG and the echocardiogram in tricuspid stenosis 

The ECG in tricuspid stenosis shows right atrial enlargement (increased P wave amplitude in leads II, and V1-see ECG section). In a patient with clinical manifestations of right heart failure, the presence of ECG signs of right atrial enlargement in the absence of ECG signs indicative of right ventricular dilatation or hypertrophy should raise a suspicion of tricuspid valve disease.
The echocardiogram in tricuspid valve stenosis
Echocardiography shows thickening of the leaflets of the tricuspid valve with a dome-shaped valve in diastole (this is similar to the dome-shaped appearance of the mitral valve in diastole observed in mitral stenosis). There is a large dilatation of the right atrium and the superior vena cava (right atrial enlargement is also seen in the postero-anterior chest x-ray).
The area of the functional tricuspid valve orifice can be calculated by using continuous wave doppler in the same way as in mitral stenosis with a calculation of the PHT-pressure half time. A severe narrowing of the tricuspid valve is indicated by PHT ≥190 ms and an orifice area ≤1 cm2. Continuous wave doppler also calculates the mean transvalvular pressure gradient, which according to the European guidelines (by ESC-2012) in severe tricuspid stenosis is ≥ 5 mmHg. In addition, echocardiography indicates whether there is also tricuspid regurgitation, as well as other valvular diseases (often rheumatic mitral disease).
Treatment of tricuspid valve stenosis
Systemic venous congestion is treated by the limitation of salt consumption and administration of a diuretic drug. This treatment of venous congestion may reduce hepatic congestion and improve liver function, thereby reducing the risk of surgery (especially the increased risk of bleeding associated with hepatic dysfunction, since the blood coagulation factors are synthesized in the liver).
In patients with moderate or severe tricuspid stenosis (with a mean transvalvular diastolic pressure gradient o> 4 mmHg and a calculated valve orifice area <1.5-2 cm2), surgical treatment with surgical repair of the tricuspid valve is recommended or, if the repair is not feasible, tricuspid valve replacement with a bioprosthetic valve. Preferably, surgery for tricuspid valve disease is performed along with the operative treatment of commonly coexisting mitral valve disease. Because tricuspid stenosis is very rarely an isolated disorder and is usually accompanied by moderate to severe tricuspid regurgitation and rheumatic mitral valve disease, balloon tricuspid valvuloplasty is very rarely applicable. This is true, since this procedure is contraindicated when there is a significant tricuspid regurgitation, and of course, it does not treat mitral valve disease, which often coexists.

A video (echocardiogram) of Rheumatic tricuspid stenosis and regurgitation
by Dr Venkatesan Sangareddi
A Video Echo of a patient with tricuspid valve stenosis (with tricuspid regurgitation also) and mitral valve stenosis
by Dr. Maged Al Ali


Bibliography and links 

Baumgarther H, et al. 2017 ESC/EACTS Guidelines for the management of valvular heart disease: The Task Force for the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS), European Heart Journal, , ehx391,

EAE/ASE: Echocardiographic assessment of stenotic heart valves (A very useful guideline in slides)

Wickiecho: Pulmonary stenosis

Pulmonic Valvular Stenosis-emedicine/medscape

Holzer RJ, et al. Transcatheter pulmonary valve replacement: state of the art. Catheter Cardiovasc Interv. 2016;87(1):117–128. [PMID: 26423185]  
American College of Cardiology: Tricuspid valve disease: 10 points to remember
Rodés-Cabau J, Taramasso M, O’Gara PT. Diagnosis and Treatment of Tricuspid Valve Disease: Current and Future Perspectives. Lancet 2016;Apr 2

B Phillips. Tricuspid Valve Disease: A Few Points Regarding Right-Sided Heart Failure. The Internet Journal of Thoracic and Cardiovascular Surgery. 2004 Volume 7 Number 1.

No comments:

Post a Comment