Pulmonic stenosis (PS) refers to a dynamic or fixed anatomic obstruction to flow from the right ventricle (RV) to the pulmonary arterial vasculature. Although most commonly diagnosed and treated in the pediatric population, individuals with complex congenital heart disease and more severe forms of isolated PS are surviving into adulthood and require ongoing assessment and cardiovascular care.[1]
PS can be due to isolated valvular (90%), subvalvular, or peripheral (supravalvular) obstruction, or it may be found in association with more complicated congenital heart disorders. The characteristics of the various types of PS are described in this section.[2]
Valvular pulmonic stenosis
Isolated valvular PS comprises approximately 10% of all congenital heart disease. Typically, the valve commissures are partially fused and the 3 leaflets are thin and pliant, resulting in a conical or dome-shaped structure with a narrowed central orifice. Poststenotic pulmonary artery dilatation may occur owing to "jet-effect" hemodynamics.
Alternatively, approximately 10-15% of individuals with valvar PS have dysplastic pulmonic valves. These valves have irregularly shaped, thickened leaflets, with little, if any, commissural fusion, and they exhibit variably reduced mobility. The leaflets are composed of myxomatous tissue, which may extend to the vessel wall. The valve annulus is usually small, and the supravalvular area of the pulmonary trunk is usually hypoplastic. Poststenotic dilatation of the pulmonary artery is uncommon. Approximately two thirds of patients with Noonan syndrome have PS due to dysplastic valves.
A bicuspid valve is found in as many as 90% of patients with tetralogy of Fallot, whereas it is rare in individuals with isolated valvar PS.
With severe valvular PS, subvalvular right ventricular hypertrophy can cause infundibular narrowing and contribute to the right ventricular outflow obstruction. This often regresses after correction of valvular stenosis.
With severe PS and decreased right ventricular chamber compliance, cyanosis can occur from right-to-left shunting if a concomitant patent foramen ovale, atrial septal defect, or ventricular septal defect is present.
Subvalvular pulmonic stenosis
Subvalvular PS occurs as a narrowing of the infundibular or subinfundibular region, often with a normal pulmonic valve. This condition is present in individuals with tetralogy of Fallot and can also be associated with a ventricular septal defect (VSD).
Double-chambered right ventricle is a rare condition associated with fibromuscular narrowing of the right ventricular outflow tract with right ventricular outflow obstruction at the subvalvular level.
Peripheral pulmonary stenosis
Peripheral pulmonary stenosis (PPS) can cause obstruction at the level of the main pulmonary artery, at its bifurcation, or at the more distal branches. PPS may occur at a single level, but multiple sites of obstruction are more common. PPS may be associated with other congenital heart anomalies such as valvular PS, atrial septal defect (ASD), VSD, or patent ductus arteriosus (PDA); 20% of the patients with tetralogy of Fallot have associated PPS.
Functional or physiologic PPS is a common cause of a systolic murmur in infants. It occurs in both premature and full-term infants; with time, the pulmonary artery grows, and the murmur usually disappears within a few months.
Poststenotic dilatation occurs with discrete segmental stenosis but is absent if the stenotic segment is long or if the pulmonary artery is diffusely hypoplastic.
PPS is associated with various inherited and acquired conditions including rubella and the Alagille, cutaneous laxa, Noonan, Ehlers-Danlos, and Williams syndromes.
PS is a common form of congenital heart disease that occasionally is diagnosed for the first time in adulthood. Isolated valvular PS comprises approximately 10% of all congenital heart disease.
Mortality/Morbidity
Except for critical stenosis in neonates, survival is the rule in congenital PS.
The long-term course of patients with mild PS is indistinguishable from that of the unaffected population. Mild PS does not tend to progress in severity; rather, pulmonic valve orifice size usually increases with body growth. However, untreated severe PS may result in outflow obstruction that progresses over a period of years; 60% of patients with severe PS require intervention within 10 years of diagnosis.
Most children and adults with mild-to-moderately severe pulmonic stenosis (PS) are asymptomatic. Those with severe PS may experience exertional dyspnea and fatigue.
In extremely rare cases, patients present with exertional angina, syncope, or sudden death.
Peripheral edema and other typical symptoms occur with right heart failure.
Cyanosis is present in those with significant right-to-left shunt via a patent foramen ovale, atrial septal defect, or ventricular septal defect.
A precordial heave or a palpable impulse from the RV along the left parasternal border may suggest severe PS. In the left upper sternal border, a systolic thrill may be palpable at the level of the second intercostal space.
In valvular PS, auscultation reveals a normal S1 and a widely split S2, with a soft and delayed P2. Valvular PS typically causes a systolic crescendo-decrescendo ejection murmur in the left upper sternal border that increases with inspiration and radiates diffusely.
In patients with pliable valve leaflets, a systolic ejection click may precede the murmur, distinguished from aortic ejection sounds by its increased intensity on expiration and softening on inspiration. As the severity of PS increases, the ejection murmur increases in intensity, its duration prolongs, and its peak becomes more delayed. No ejection click is heard when dysplasia or severe leaflet thickening immobilizes the valve leaflets, or if the stenosis is above or below the pulmonic valve.
The murmur of PPS may be continuous, softer, and higher pitched.
Mild-to-moderately severe desaturation or frank cyanosis may be noted with right-to-left shunting through a patent foramen ovale, atrial septal defect, or ventricular septal defect.
Other forms of acquired pulmonic stenosis include the following:
PS is a rare manifestation of rheumatic heart disease, and it follows involvement of the mitral and aortic valves.
Carcinoid may result in development of myxomatous plaques in the RV outflow tract, with distortion and constriction of the pulmonic ring, as well as fusion or destruction of pulmonary valve leaflets, resulting in both stenosis and regurgitation.
Rarely, cardiac tumors can grow on or into the RV outflow tract and cause flow obstruction.
Sinus of Valsalva aneurysms and aortic graft aneurysms are extracardiac entities that can cause PS by external compression.
A characteristic radiographic finding, even with mild valvular pulmonic stenosis (PS), is prominence of the main, right, or left pulmonary arteries caused by poststenotic dilatation.
The intrapulmonary vasculature usually appears normal, even in severe PS.
In critical PS, the pulmonary vasculature may appear decreased if significant right-to-left shunting occurs through a patent foramen ovale or atrial septal defect or if severe unilateral pulmonary artery branch obstruction is present.
The overall heart size usually is normal unless RV failure or tricuspid regurgitation develops.
A prominent right heart border suggesting right atrial enlargement may be present in as many as 50% of affected individuals.
Echocardiography provides a definitive confirmation of the diagnosis of PS. Both 2-dimensional and Doppler techniques should be used to comprehensively evaluate the pulmonic valve.
Using 2-dimensional imaging, thickening of the valves, characteristic doming of nondysplastic valves, and right ventricular (RV) hypertrophy can be noted readily (see image below). RV size and systolic function, right atrial (RA) size, and pulmonary artery dimensions can be quantified in most patients.
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Pulmonic stenosis. Echocardiogram of a patient with severe pulmonic stenosis. This image shows a parasternal short axis view of the thickened pulmonar....
Color Doppler aids in both defining high velocity jets and localizing their origin. Pulsed waved Doppler (placed just proximal to the site of obstruction) and continuous wave Doppler are used to measure jet velocity, which can be converted to pressure gradient using the modified Bernoulli equation. Normally, no systolic gradient is present across the pulmonic valve. With PS, however, the RV systolic pressure increases and a pressure gradient occurs between the RV and pulmonary artery. Doppler studies of the stenotic valve can determine the severity of the gradient (see image below).
View Image
Pulmonic stenosis. Echocardiogram of a patient with severe pulmonic stenosis. This image shows a Doppler scan of the peak velocity (5.2 m/s) and gradi....
The pulmonary valve area of a healthy adult is 2.0 cm2/m2 of body surface area. Mild valvular PS is defined by a valve area larger than 1 cm2 and a transvalvular pressure gradient of less than 50 mm Hg. Moderately severe PS occurs if the valve area is 0.5-1.0 cm2, with a transvalvular pressure gradient between 50 and 75 mm Hg. Severe PS is defined by a valve area smaller than 0.5 cm2 and a transvalvular pressure gradient greater than 75 mm Hg.
RV hypertrophy with asymmetric septal hypertrophy may be present. In addition, restrictive physiology can be demonstrated by Doppler interrogations of tricuspid inflow, hepatic vein flow, and Doppler tissue imaging. A restrictive RV pattern is associated with worse RV systolic function and worse exercise tolerance.
Doppler evidence of right-sided pressures approaching or exceeding systemic pressures or a 2-dimensional echocardiogram demonstrating paradoxical septal motion during systole with reversal of the usual right convex curvature of the interventricular septum is an indication for therapeutic intervention (see image and video below).
View Image
Pulmonic stenosis. Echocardiogram of a patient with severe pulmonic stenosis. This image shows that moderately severe pulmonary insufficiency (orange ....
View Video
This video is an echocardiogram of a patient with severe pulmonic stenosis. The first segment shows the parasternal short axis view of the thickened pulmonary valve. The second segment shows the presence of moderate pulmonary insufficiency (orange color flow).AV=Aortic valve, PV=Pulmonary valve, PA=Pulmonary artery, PI=Pulmonary insufficiency
Cardiac catheterization generally is not needed to verify the findings of noninvasive tests, except when a significant discrepancy is noted between clinical findings and echocardiographic findings. When performed, cardiac catheterization can diagnose PS by a pressure gradient from the pulmonary artery to the RV on "pull-back" of the pulmonary artery catheter. Cardiac catheterization may be useful in assessing the presence of concomitant congenital abnormalities.
In the case of isolated PPS, pulmonary angiography may be needed to establish the diagnosis.
Traditionally, pulmonic stenosis (PS) was treated by surgical valvotomy. Since its introduction in 1982, however, percutaneous balloon valvuloplasty has become the initial intervention in children, adolescents, and adults with congenital valvar PS. Balloon valvuloplasty should be considered in any patient with a transvalvular pressure gradient greater than 50 mm Hg.
Occasionally, balloon valvuloplasty is not successful. These patients tend to have valvular dysplasia (eg, Noonan syndrome) or a hypoplastic pulmonic valve annulus and, therefore, may require surgical valvotomy.
Pulmonary artery balloon angioplasty with or without placement of an expandable metal stent can be used to treat supravalvular PS and PPS. Expandable metal stents can overcome an obstruction successfully; however, the need for stent reexpansion as the individual grows remains problematic.
The American Heart Association/American College of Cardiology[3] and the European Society of Cardiology[4] have published guidelines on the management of patients with valvular heart disease.
Avoidance of vigorous exercise in pregnancy is recommended, especially during the second half of pregnancy in patients with moderate or severe gradients.
One study found that pregnant patients with PS had favorable outcomes and low maternal and fetal complications. This is in contrast to left heart obstructive lesions such as aortic and mitral stenosis.[5]
Athletes
Athletes with mild PS and gradients less than 50 mm Hg have no activity limitations. Those with more severe PS can participate in low-intensity competitive sports.
Infective endocarditis prophylaxis: The American Heart Association (AHA) Guidelines on Prevention of Bacterial Endocarditis considers all forms of isolated pulmonic stenosis (PS) to be in the moderate-risk category, and any PS associated with complex congenital heart disease to be in the high-risk category. Therefore, antibiotic prophylaxis is recommended for all forms of PS.
Except for critically severe stenosis in neonates, survival is the rule for individuals with congenital PS.[6] The long-term course of individuals with mild PS is indistinguishable from that of the unaffected population. Mild PS does not tend to progress in severity; rather, pulmonic valve orifice size usually increases with body growth.
Severe PS may result in outflow obstruction that progresses over a period of years despite body growth (60% of patients require intervention within 10 y of diagnosis). With appropriate intervention, those with moderately severe PS have an excellent prognosis.
The functional effect of PS may change during an individual's lifetime such that symptoms or limitations occurring in childhood may resolve by adulthood.
Available data support relieving moderately severe and severe PS in childhood, with follow-up care through adolescence and into adulthood. When PS is corrected during childhood, the life expectancy of the affected individual matches that of the unaffected age- and sex-matched cohort. The more severe and protracted the course of PS, the less optimal the outcome of intervention, including death due to RV failure in the most severe cases.
Balloon valvuloplasty is preferred, provided the valve is compliant and mobile. Those with severe valvular fibrocalcific thickening are more likely to require a surgical approach. The recurrence rate of PS in patients who are treated surgically is approximately 4%. Long-term results of balloon valvuloplasty are comparable to the results of surgical repair, with the rate of recurrence of severe PS less than 5%. A recent study shows that long-term follow-up of patients after surgical treatment for isolated pulmonary valve stenosis resulted in a high rate of reinterventions (53% at a median follow-up of 34 years). Thus, close follow-up in postsurgical patients is needed.
Adult patients are more likely to present with subvalvular hypertrophic pulmonic stenosis or valvular fibrocalcific thickening. Secondary subvalvular hypertrophic stenosis regresses following correction of the primary valvular abnormality, and residual dilatation of the pulmonary trunk is not significant clinically, even when marked. Recognizing subvalvular hypertrophy is important, since it may lead to dynamic outflow obstruction during the acute phase following correction of valvular stenosis. With few exceptions, postvalvuloplasty pulmonic regurgitation is of mild-to-moderate severity.
A study by Zdradzinski et al indicated that specific guidelines for the timing of valve replacement need to be developed for patients with isolated PS who develop pulmonic regurgitation after surgical valvotomy. The study, which involved 109 adult patients, including 34 patients with isolated PS and 75 with tetralogy of Fallot, investigated whether recommendations for valve replacement in patients with tetralogy of Fallot who develop pulmonic regurgitation after complete repair can be applied when regurgitation develops after valvotomy for isolated PS.[7]
The report found that the degrees of pulmonic regurgitation and symptom severity were similar between the two groups of patients, but an analysis of biventricular systolic function and QRS width indicated that the morphologic changes that occur in association with tetralogy of Fallot and its repair involve more than just the effects of pulmonic regurgitation.[7]
Xiushui (Mike) Ren, MD, Cardiologist, The Permanente Medical Group; Associate Director of Research, Cardiovascular Diseases Fellowship, California Pacific Medical Center
Disclosure: Nothing to disclose.
Coauthor(s)
Lauralyn B Cannistra, MD, FACC, Director of Echocardiography Lab and Cardiac Rehabilitation, Assistant Professor, Department of Medicine, Memorial Hospital of Rhode Island, Brown University School of Medicine
Disclosure: Nothing to disclose.
Specialty Editors
Francisco Talavera, PharmD, PhD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference
Disclosure: Received salary from Medscape for employment. for: Medscape.
Marschall S Runge, MD, PhD, Charles and Anne Sanders Distinguished Professor of Medicine, Chairman, Department of Medicine, Vice Dean for Clinical Affairs, University of North Carolina at Chapel Hill School of Medicine
Disclosure: Received honoraria from Pfizer for speaking and teaching; Received honoraria from Merck for speaking and teaching; Received consulting fee from Orthoclinica Diagnostica for consulting.
Chief Editor
Richard A Lange, MD, MBA, President, Texas Tech University Health Sciences Center, Dean, Paul L Foster School of Medicine
Disclosure: Nothing to disclose.
Additional Contributors
Park W Willis IV, MD, Sarah Graham Distinguished Professor of Medicine and Pediatrics, University of North Carolina at Chapel Hill School of Medicine
Pulmonic stenosis. Echocardiogram of a patient with severe pulmonic stenosis. This image shows a parasternal short axis view of the thickened pulmonary valve.
Pulmonic stenosis. Echocardiogram of a patient with severe pulmonic stenosis. This image shows a Doppler scan of the peak velocity (5.2 m/s) and gradients (peak 109 mm Hg, mean 65 mm Hg) across the valve.
Pulmonic stenosis. Echocardiogram of a patient with severe pulmonic stenosis. This image shows that moderately severe pulmonary insufficiency (orange color flow) is also present.
This video is an echocardiogram of a patient with severe pulmonic stenosis. The first segment shows the parasternal short axis view of the thickened pulmonary valve. The second segment shows the presence of moderate pulmonary insufficiency (orange color flow).AV=Aortic valve, PV=Pulmonary valve, PA=Pulmonary artery, PI=Pulmonary insufficiency
Pulmonic stenosis. Echocardiogram of a patient with severe pulmonic stenosis. This image shows a parasternal short axis view of the thickened pulmonary valve.
Pulmonic stenosis. Echocardiogram of a patient with severe pulmonic stenosis. This image shows a Doppler scan of the peak velocity (5.2 m/s) and gradients (peak 109 mm Hg, mean 65 mm Hg) across the valve.
Pulmonic stenosis. Echocardiogram of a patient with severe pulmonic stenosis. This image shows that moderately severe pulmonary insufficiency (orange color flow) is also present.
This video is an echocardiogram of a patient with severe pulmonic stenosis. The first segment shows the parasternal short axis view of the thickened pulmonary valve. The second segment shows the presence of moderate pulmonary insufficiency (orange color flow).AV=Aortic valve, PV=Pulmonary valve, PA=Pulmonary artery, PI=Pulmonary insufficiency
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