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Pulmonic Stenosis Last Updated: May 31, 2006 |
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| Synonyms and related keywords: pulmonic stenosis, pulmonary valve stenosis, PS, peripheral pulmonic stenosis, PPS, congenital heart anomalies, valvular PS, atrial septal defect, ASD, ventricular septal defect, VSD, patent ductus arteriosus, congenital heart disease, congenital heart defect
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AUTHOR INFORMATION
| Section 1 of 10   |
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| Author: Xiushui (Mike) Ren, MD, Clinical Echocardiography Fellow, Department of Cardiology, University of California at San Francisco Coauthor(s): Pablo J Saavedra, MD, Fellow, Department of Cardiology, Vanderbilt University School of Medicine; Lauralyn B Cannistra, MD, Director of Echocardiography Lab and Cardiac Rehabilitation, Assistant Professor, Department of Medicine, Memorial Hospital of Rhode Island, Brown University School of Medicine |
| Xiushui (Mike) Ren, MD, is a member of the following medical societies:
Alpha Omega Alpha,
American College of Cardiology, and
American Society of Echocardiography |
| Editor(s): Park W Willis IV, MD, Associate Chief of Cardiology, Program Director, Adult Cardiovascular Disease Fellowship, Professor, Departments of Medicine and Pediatrics, University of North Carolina School of Medicine and Hospitals; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine;
Marschall S Runge, MD, PhD, Marion Covington Distinguished Professor of Medicine, Vice Dean for Clinical Affairs, School of Medicine, Chairman, Department of Medicine, University of North Carolina at Chapel Hill;
Amer Suleman, MD, Consultant in Electrophysiology and Cardiovascular Medicine, Department of Internal Medicine, Division of Cardiology, Medical City Dallas Hospital;
and Michael E Zevitz, MD, Assistant Professor of Medicine, Finch University of the Health Sciences, The Chicago Medical School; Consulting Staff, Private Practice |
Disclosure
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INTRODUCTION
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Background: Pulmonic stenosis (PS) refers to a dynamic or fixed anatomic obstruction to flow from the right ventricle (RV) to the pulmonary arterial vasculature. Although diagnosed and treated primarily 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. Pathophysiology: PS can be an isolated finding at valvular (90%), subvalvular, or peripheral (supravalvular) levels, and also can be found in association with more complicated congenital heart disorders. The characteristics of the various types of PS are described in this section.
Valvular pulmonic stenosis
Valvular PS typically is an isolated anomaly, comprising approximately 10% of all congenital heart disease. Typically, the 3 leaflets are thin and pliant with partially fused commissures, resulting in a conical or dome-shaped structure with a narrowed central orifice. Poststenotic pulmonary artery dilatation may occur owing to "jet-effect" hemodynamics.
Of patients with valvular PS, approximately 10-15% have dysplastic pulmonic valves. These valves have irregularly thickened valve leaflets, with little, if any, commissural fusion, and exhibit variably reduced mobility. They are composed of myxomatous tissue, which may extend to the vessel wall. The valve annulus is small, and the supravalvular area of the pulmonary trunk is usually hypoplastic. Poststenotic dilatation is less common with dysplastic valve stenosis than classic PS. Approximately two thirds of patients with Noonan syndrome have PS due to dysplastic valves.
Although uncommon in isolated valvular PS, a bicuspid valve is found in as many as 90% of patients with tetralogy of Fallot.
In moderately severe-to-severe valvular PS, subvalvular hypertrophy can cause infundibular narrowing and obstructive hemodynamics, which regress after correction of valvular stenosis.
Cyanosis can occur with right-to-left atrial shunting through a patent foramen ovale; this is due to critical PS and decreased right ventricular chamber compliance.
Subvalvular pulmonic stenosis
Subvalvular PS occurs as a narrowing of the infundibular or subinfundibular region, often with a normal pulmonic valve. This condition can 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 bifurcation of 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; 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 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. Noonan syndrome is named after Dr. Jacqueline A. Noonan, who in 1968 reported 19 patients with Turner phenotype, 17 of whom had associated pulmonic stenosis. Noonan syndrome is an autosomal dominant disorder characterized by dysmorphic facial features, webbed neck, chest deformity, cryptorchidism, mental retardation, bleeding diatheses, proportionate short stature, and pulmonic stenosis. Frequency:
- In the US: PS is a common form of congenital heart disease that occasionally is diagnosed for the first time in adulthood.
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 despite body growth, and 60% of patients with severe PS require intervention within 10 years of diagnosis.
Sex: A slight female predominance exists.
History: - Most children and adults with mild-to-moderately severe pulmonic stenosis (PS) are asymptomatic.
- Those with moderately severe-to-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.
Physical: - A precordial heave or a palpable impulse from the RV along the left parasternal border may suggest moderately severe-to-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.
Causes: See Pathophysiology. - Other forms of acquired pulmonic stenosis
- PS is a rare manifestation of rheumatic heart disease.
- 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.
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DIFFERENTIALS
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Cardiac Neoplasms, Primary
Cardiac Sarcoma
[Cardiac Tumors, Benign]
Sinus of Valsalva Aneurysm
Other Problems to be Considered:
Congenital heart abnormality (see Causes)
Rheumatic valvular heart disease
Carcinoid heart disease |
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Patient Education
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Imaging Studies:
- 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 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 hypertrophy can be noted readily (see Image 1). RV size and systolic function, RA size, and pulmonary artery can be quantified in most patients.
- 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 forms between the RV and pulmonary artery. Doppler studies of the stenotic valve area can determine the severity of the gradient (see Image 2).
- 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 peak transvalvular gradient of less than 50 mm Hg.
- Moderately severe PS occurs if the valve area is 0.5-1.0 cm2, with a peak transvalvular gradient between 50 and 75 mm Hg.
- Severe PS is defined by a valve area smaller than 0.5 cm2 and a peak transvalvular gradient of greater than 75 mm Hg.
- Newer data suggest that Doppler-derived mean transpulmonary gradient is more accurate than peak gradient.
- RV hypertrophy with asymmetric septal hypertrophy may be present.
- 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 requires prompt therapeutic intervention (see Images 3-4).
- Cardiac catheterization and pulmonary angiography
- 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.
- In the case of isolated PPS, pulmonary angiography may be needed to establish the diagnosis.
Other Tests:
- The degree of (right) ventricular hypertrophy on the ECG is largely correlated directly with the severity of PS.
- With mild PS, 50% of patients have a normal ECG tracing or only mild right-axis deviation.
- With moderately severe PS, right-axis deviation and increased R-wave amplitude in V1 are seen.
- Severe PS is associated with extreme right-axis deviation, a dominant R wave in AVR, and a prominent R wave (>20 mm) in V1.
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TREATMENT
| Section 6 of 10 |
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Surgical Care: - Traditionally, PS was treated by surgical valvotomy.
- Since its introduction in 1982, percutaneous balloon valvuloplasty has become the initial intervention in children with congenital PS. Although experience is limited in adolescents and adults, long- and short-term results appear to be favorable if the valve is thin and compliant. Balloon valvuloplasty should be considered in any patient with a transvalvular 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. In general, no advantage is gained by delaying intervention for PS.
- Pulmonary artery balloon angioplasty has had limited success, but supravalvular and PPS are more difficult to treat.
- Expandable metal stents can overcome an obstruction successfully; however, the need for stent reexpansion as the individual grows remains problematic.
Activity: For more details, see Special Concerns. - Pregnancy: Avoidance of vigorous exercise is recommended, especially during the second half of pregnancy in patients with moderate or severe gradients.
- 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.
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FOLLOW-UP
| Section 7 of 10 |
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Deterrence/Prevention:
- Infective endocarditis prophylaxis: The American Heart Association (AHA) Guidelines on Prevention of Bacterial Endocarditis considers all forms of isolated 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.
Prognosis:
- Except for critically severe stenosis in neonates, survival is the rule for individuals with congenital PS.
- 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.
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MISCELLANEOUS
| Section 8 of 10 |
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Special Concerns:
- Pulmonic stenosis in pregnancy
- Valvular heart disease, including PS, should warrant follow-up care by a high-risk obstetrics team. The hemodynamic changes in pregnancy—which include increase in plasma volume proportionally greater than red blood cell volume, increase in cardiac stroke volume, decrease in systemic vascular resistance, decrease in pulmonary vascular resistance with a drop in pulmonary pressures, and decrease in venous return that is more marked in the third trimester—can exacerbate the symptoms of PS.
- In general, pregnancy is tolerated well by individuals who have asymptomatic PS before conception, even if the degree of stenosis is severe.
- When symptoms are referable to PS, they are similar to those of individuals who are not pregnant and symptomatic. The symptoms of healthy pregnancy can resemble those of PS, including exertional fatigue, dyspnea, orthopnea, presyncope, and, rarely, frank syncope. Palpitations due to arrhythmias have been noted to be more common in those with PS.
- Mild PS produces a murmur similar to that of the benign flow murmur of pregnancy, which typically increases in intensity as the stroke volume is augmented. During the physical examination, this murmur can be distinguished from the flow murmur of pregnancy by noting a prominent jugular venous a wave, an RV lift, a systolic thrill over the pulmonic area, a pulmonic ejection click, and a diminished or absent P2. ECG and echocardiographic evaluation are essential in confirming clinical suspicion. Fetal echocardiography is indicated in patients with PS or tetralogy of Fallot.
- Avoidance of vigorous exercise is recommended, especially during the second half of pregnancy in patients with moderate-to-severe gradients.
- Balloon valvuloplasty is recommended in nonpregnant patients when the gradient across the right ventricular outflow track is greater than 50 mm Hg at rest or when the patient is symptomatic.
- If severe PS is detected during pregnancy, percutaneous balloon valvuloplasty to relieve the obstruction usually can be accomplished safely, obviating the need to terminate the pregnancy.
- Arrhythmias are treated according to the severity of symptoms.
- Considerations for labor and delivery
- Patients who are asymptomatic during pregnancy generally tolerate labor and delivery well.
- For more severe valvular disease, a high-risk obstetrics team along with a cardiology consultation may be required to manage deliveries.
- Antibiotic prophylaxis generally is not recommended for cesarean delivery and is considered optional in women with PS that is associated with complex congenital heart disease.
- See AHA Guidelines on Prevention of Bacterial Endocarditis.
- Pulmonic stenosis in athletes
- Athletes with mild PS gradients (ie, <50 mm Hg) have no activity limitations.
- Those with more severe PS can participate in low-intensity competitive sports; their treatment should be directed by the criteria discussed in Treatment.
| Caption: Picture 4. 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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Picture Type: Movie |
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BIBLIOGRAPHY
| Section 10 of 10 |
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