***Ejection click is softer and absent with increasing severity
***Ejection click is softer and absent with increasing severity
***Wide split [[S2 splitting|S2]] with reduced or absent [[Heart sounds|P2]] component
***Wide split [[S2 splitting|S2]] with reduced or absent [[Heart sounds|P2]] component
***Right sided [[S4]] can be audible. {| class="wikitable" ! !Mild !Severe |- |Physical Examination findings |normal jugular venous pulse, absent right ventricle lift, ejection click in the pulmonary area which decreases with inspiration, [[ejection systolic murmur]] in the pulmonary area heard in the ending of mid systole increasing in intensity during inspiration. |
***Right sided [[S4]] can be audible.
{| class="wikitable"
! !Mild !Severe |- |Physical Examination findings |normal jugular venous pulse, absent right ventricle lift, ejection click in the pulmonary area which decreases with inspiration, [[ejection systolic murmur]] in the pulmonary area heard in the ending of mid systole increasing in intensity during inspiration. |
*Elevated [[Jugular venous pressure|JVP]] with a prominent "A" wave
*Elevated [[Jugular venous pressure|JVP]] with a prominent "A" wave
Synonyms and keywords: Valvular Pulmonary Stenosis, Pulmonic Stenosis, Right Ventricular Outlet Obstruction, supravalvular pulmonic stenosis, infundibular pulmonic stenosis, RVOT, congenital pulmonary valve stenosis, Congenital stenosis of pulmonary valve, Narrowing of pulmonary valve
Overview
Pulmonary stenosis accounts for 8% of all congenital heart disease and worldwide the prevalence of pulmonic stenosis is 1 per 2000 births.[1] The pulmonic valve stenosis is classified into 3 different subtypes based on the location of the stenosis. Isolated valvular stenosis is the most common sub-type, with dome shaped morphology and dysplastic valves. Patients with mild stenosis usually have a beningn course and do not progress, patients with moderate to severe stenosis manifest symptoms of dyspnea, chest pain, fatigue and syncope. If left untreated patients progress to right heart failure. 2D Echo is the standard diagnostic test to identify the location and to assess the severity of the stenosis. Symptomatic patients undergo valvulotomy or balloon valvuloplasty based on the morphology of the affected valves. Timely intervention in patients with valvular stenosis has good outcomes and excellent prognosis. Guidelines for evaluation, approach and treatment are well-defined.
Historical Perspective
The pulmonary valve and its function of allowing blood to the lungs for nourishment was first described by Hippocrates.[2]
Erasistratus, mentioned the involvement of the pulmonary valve in the unidirectional flow.
Galen described the membranes of the valves and named them as "semilunar".
Mondino de Luzzi designed the sketch of the pulmonary valves in the anatomical position for the first time.
Realdo Colombo described the pulmonary circulation for the first time.
Classification
Based on the anatomic location
Pulmonic stenosis is classified into valvular, subvalvular (infundibular) and supravalvular based on the location of the stenosis in relation to the pulmonary valve. Valvular stenosis is most common of the three sub-types.
Sub-valvular stenosis: It can be infudibular or sub-infundibular. Infundibular stenosis is a feature of tetralogy of fallot. Sub-infundibular pulmonic stenosis is known as ‘double chambered right ventricle’ dividing the right ventricle into a high pressure inlet and a low pressure outlet causing a progressive right ventricular outflow tract obstruction.[3]
Valvular stenosis: It is the most common cause of pulmonic stenosis. The valves are usually dome shaped or dysplastic affecting the movement of the cusps. It can be isolated or associated with other congenital heart diseases such as atrial septal defects, Ebstein’s anomaly, double outlet right ventricle, and transposition of the great arteries.
Supravalvular stenosis: The obstruction is usually in the common pulmonary trunk or in the bifurcation or the pulmonary branches. It is commonly associated with other congenital syndromes such as Williams–Beuren, Noonan, Allagile, DiGeorge, and Leopard syndrome.
Based on the severity of the stenosis
Severity of pulmonary stenosis is classified based on the estimated peak velocity and peak resting gradient calculated using modified Bernoulli equation. It is classified into:[4]
Mild: Peak velocity less than 3m/s and peak gradient is less than 36 mm Hg.
Moderate: Peak velocity is 3 to 4m/s and peak gradient is 36 to 64mm Hg.
Severe: Peak velocity is greater than 4m/s and peak gradient is greater than 64mm Hg.
Other anatomic abnormalities may be present, such as narrowed RVOT.
Vmax >4 m/s; peak instantaneous gradient >64 mm Hg
Right ventricular hypertrophy
Possible RV, RA enlargement
Poststenotic enlargement of main Pulmonary artery
None or variable and dependent on severity of obstruction
According to 2014 AHA/ACC Guidelines for the Management of Patients With Valvular Heart Disease, progression of valvular heart disease (VHD) are defined as follows:[6]
Stage
Definition
Description
A
At risk
Patients with risk factors for development of VHD
B
Progressive
Patients with progressive VHD (mild-to-moderate severity and asymptomatic)
C
Asymptomatic severe
Asymptomatic patients who have the criteria for severe VHD:
C1: Asymptomatic patients with severe VHD in whom the left or right ventricle remains compensated
C2: Asymptomatic patients with severe VHD with decompensation of the left or right ventricle
D
Symptomatic severe
Patients who have developed symptoms as a result of VHD
Pathophysiology
Pathogenesis
Pulmonic valve stenosis with fused commisures affect the flexibility of the valve causing obstruction of the outflow tract. In patients with dysplastic valves, the cusps are not fused but they are rigid from intrinsic thickening resulting in the narrowing of the outflow tract.[7]
These morphological changes affect the complete opening of the pulmonic valve in ventricular systole causing elevated right ventricular systolic pressures and leading to right ventricular remodelling.[8]
The obstruction leads to increased pressure overload in the right ventricle as it has to push the blood against resistance.
Genetics
These are a common genetic disorders associated with pulmonic stenosis:[9]
A rare association of pulmonic stenosis with an unrepaired ASD is reported.[19]
Epidemiology and Demographics
Pulmonary stenosis accounts for 8% of all congenital heart disease.
Worldwide, the prevalence of pulmonic stenosis is 1 per 2000 births.[1]
The prevalence of pulmonic stenosis and tetralogy of fallot is higher in asian countries.[20]
Causes
Pulmonary valve stenosis is due to a structural changes resulting from thickening and fusion of the pulmonary valve. The valve pathology can be congenital or acquired. The following is the list of causes:
Congenital causes
These account for 95% of the cases with pulmonic stenosis which include isolated pulmonic valve pathologies and its associations with other congenital heart diseases.[21]
Functional Pulmonic Stenosis: Primary cardiac tumours obstructing the right ventricular outflow tract such as leiomyosarcoma.[36]
Differentiating from other diseases
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Right ventricular outflow tract obstruction must be distinguished from an ASD, a small VSD, aortic stenosis, and acyanotic or pink tetralogy of Fallot.
Atrial septal defect: Presence of systolic ejection murmur, wide fixed split S2, EKG showing RVH. In ASD the split of the S2 is fixed, there is no ejection click.
Acyanotic or pink tetralogy of Fallot: with amyl nitrate and increased venous return the murmur of PS increases, and the murmur of tetralogy decreases because of peripheral dilation and an increase in right to left shunting.
Risk Factors
Common risk factors in the development of congenital heart disease apply for pulmonic stenosis and include:[37]
Patients with congenital pulmonary stenosis manifest clinical features few hours after birth, in childhood or in adulthood. Manifestation of symptoms, symptom severity and the outcomes are dependent on the severity of the disease.[39] Patients with mild pulmonic stenosis have a benign course and do not progress.[40] and patients with moderate and severe stenosis have dyspnea with exertion and syncope.
Prognosis
Patients with moderate to severe pulmonic valve stenosis are managed well with surgery or balloon valvuloplasty and have very good prognosis.
Anatomy (MOVE THIS SECTION TO THE PULMONARY VALVE PAGE)
Pulmonary valve is located at the distal part of the right ventricular outflow tract at the junction of the pulmonary artery.
It is located anterior and superior to the aortic valve at the level of the third intercostal space and separated from the tricuspid valve by the infundibulum of the right ventricle.
It is comprised of three equal sized, semilunar cusps or leaflets (right, left, anterior), nomenclature based on the corresponding aortic valve.
The three cusps are joined by commissures and the cusps are thinner when compared to the aortic valve, due to a low pressure in the right ventricle.
The area of the valve is related to body surface area and men usually have greater valve area when compared with women.[42]
The normal orifice area is approximately around 3cm².[43]
The pulmonary valve opens in the right ventricular systole allowing the deoxygenated blood to be delivered to the lungs.
During the right ventricular diastole the pulmonary valves close completely to prevent regurgitation of blood into the right ventricle.
Diagnosis
Gold standard diagnosis of pulmonic stenosis and assessment of severity is done by 2D echocardiography.[44]
History and Symptoms
The severity of symptoms and age of symptom onset depends on the severity of the stenosis. Clinical presentations vary as follows:
Critical pulmonary stenosis:It presents in first few hours to days of life with cyanosis. It is a condition with a very small or pin-hole orifice in the pulmonary valve which can be diagnosed prenatally. These patients have an intact interventricular septum, poorly complaint hypoplastic right ventricle and are ductus dependent. Cyanosis in these patients is due to the right to left shunting at the level of the foramen ovale.[45][46]
Mild Pulmonic Stenosis: Patients with mild stenosis are asymptomatic and are diagnosed by routine examination with an ejection systolic murmur.
Moderate Pulmonic Stenosis: Patients present with exertional dyspnea and fatigue.
Severe Pulmonic Stenosis: Patients present with exertional dyspnea, chest pain and syncope.
Patients with isolated pulmonary stenosis usually appear normal. In patients diagnosed with syndromes associated with pulmonic stenosis syndrome specific physical examination findings are demonstrated.
Cardiac examination findings are dependent on the degree of the pulmonary stenosis, the pathology of the valve and associated cardiac lesions. The common findings include as follows:
In mild stenosis findings include normal jugular venous pulse, absent right ventricle lift, ejection click in the pulmonary area which decreases with inspiration, ejection systolic murmur in the pulmonary area heard in the ending of mid systole increasing in intensity during inspiration.[47]
- |Physical Examination findings |normal jugular venous pulse, absent right ventricle lift, ejection click in the pulmonary area which decreases with inspiration, ejection systolic murmur in the pulmonary area heard in the ending of mid systole increasing in intensity during inspiration. |
Patients with mild stenosis usually do not show any EKG changes excepting for right axis deviation of -100° to -110° which is considered normal in children and adults.
In case of severe stenosis the following changes can be noted, which include:
Deep S waves in the left precordial leads with <1 R:S ratio in lead V6
Echocardiography
Transthoracic 2D Echo and Doppler imaging is the standard diagnostic test to detect and assess the severity of the stenosis.[48]
Echo shows thickened and dome shaped valves, peak and mean gradients to assess the severity can be measured by Doppler imaging.
Dysplastic valves are well visualized on echo.[49]
Always calculate the tricuspid regurgitation gradient to rule out overestimation of the pulmonary stenosis gradient.[50]
Right ventricular function and ejection fraction is better measured by a 3D echo when compared to a 2D echo.[51]
Pulmonic Stenosis 1
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Pulmonic Stenosis 2
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MRI
Cardiac MRI is very useful to study the anatomy of the right ventricular outflow tract, pulmonary artery and to locate the exact level of stenosis.[52]
Cardiac Catheterization
Cardiac catheterization is useful to measure the pressure gradients directly, but its not performed on a regular basis as echo is a reliable and non-invasive test to measure the pressure gradients.[53]
Dual-Source Computed Tomography
It is an accurate imaging technique to evaluate the function and anatomy of the pulmonary valve.[54]
Evaluation of Pulmonary Stenosis in Adolescents and Young Adults
According to 2008 ACC/AHA guidelines[7], following are the guidelines for evaluation of patients with pulmonary stenosis:
"1. An ECG is recommended for the initial evaluation of pulmonic stenosis in adolescent and young adult patients and serially every 5 to 10 years for follow-up examinations.(Level of Evidence: C) "
"2.Transthoracic Doppler echocardiography is recommended for the initial evaluation of pulmonic stenosis in adolescent and young adult patients, and serially every 5 to 10 years for follow-up examinations.(Level of Evidence: C)"
"3.Cardiac catheterization is recommended in the adoles- cent or young adult with pulmonic stenosis for evalu- ation of the valvular gradient if the Doppler peak jet velocity is greater than 3 m per second (estimated peak gradient greater than 36 mm Hg) and balloon dilation can be performed if indicated.(Level of Evidence: C) "
"1.Diagnostic cardiac catheterization is not recommended for the initial diagnostic evaluation of pulmonic stenosis in adolescent and young adult patients.(Level of Evidence: C).(Level of Evidence: C) "
Treatment
Medical Therapy
There are no specific medical therapy for the treatment of pulmonic stenosis. However, patients diagnosed with right heart failure diuretics are recommended to decrease the fluid overload.
Surgery
Indications for surgery
Surgical correction is recommended based on the peak gradient and other associated clinical features:[55]
Surgery is advised regardless of the symptoms if the Doppler derived peak instantaneous gradient greater than 64 mm Hg (peak velocity >4 m/s).
In patients with Doppler derived peak instantaneous gradient less than 64 mm Hg (peak velocity >4 m/s), surgery is advised if any of the following is present:
Asymptomatic patients with a systolic RV pressure greater than 80 mm Hg (TR velocity >4.3 m/s).
According to 2010, ESC Guidelines for the management of grown-up congenital heart disease, Indications for intervention in Right Ventricular Outlet Obstruction are as follows:[56]
"1.RVOTO at any level should be repaired regardless of the symptoms when the doppler peak gradient is >64mm Hg(peak velocity >4.0m/s), provided that the RV function is normal and no valve substitute is required(Level of Evidence: C)"
"2.In valvular PS, balloon valvulotomy should be the intervention of choice.(Level of Evidence: C) "
"3.In asymptomatic patients in whom balloon valvulotomy is ineffective and the surgical valve replacement is the only option, surgery should be performed in the presence of a systolic right ventricular pressure greater than 80mm Hg ( TR velocity >4.3m/s)(Level of Evidence: C) "
Surgical outcomes in patients with valvular stenosis is good with survival rate of 90 to 96% 25 years after the surgery when its done in the childhood.[60][61]
Survival is around 70% at 25 years when the surgery is performed in adulthood.
BPV has shown to have good outcomes in long term follow up with very low rate of re-intervention requirement.[62][63][64]
BPV has shown to have sub-optimal results in patients with dysplastic valves when compared to doming valves.[65]
Complications of the surgery
Post procedural pulmonary regurgitation is a common complication and occurs in 10 to 40% patients. Majority of the patients remain asymptomatic and only few patients develop hemodynamically significant pulmonary regurgitation.[66]
Patients with PS are recommended for a regular echocardiography to evaluate the degree of pulmonary regurgitation, RV pressure, RV function and tricuspid regurgitation. The frequency of visits is dependent on the degree of stenosis and is as follows:[7]
Mild untreated or residual pulmonic stenosis: Follow up once every 5 years.
Moderate pulmonic stenosis: Annual visit with echocardiography every 2 years.
ACC / AHA Guidelines - Indications for balloon valvotomy in Pulmonary Stenosis (DO NOT EDIT)
According to 2008 ACC/AHA guidelines[7], following are the indications for balloon valvotomy in pulmonary stenosis:
"1.Balloon valvotomy is recommended in adolescent and young adult patients with pulmonic stenosis who have exertional dyspnea, angina, syncope, or presyncope and an RV–to–pulmonary artery peak-to-peak gradient greater than 30 mm Hg at catheterization.(Level of Evidence: C) "
"2.Balloon valvotomy is recommended in asymptomatic adolescent and young adult patients with pulmonic stenosis and RV–to–pulmonary artery peak-to-peak gradient greater than 40 mm Hg at catheterization.(Level of Evidence: C) "
"1.Balloon valvotomy is not recommended in asymptomatic adolescent and young adult patients with pulmonic stenosis and RV–to–pulmonary artery peak-to-peak gradient less than 30 mm Hg at catheterization.(Level of Evidence: C) "
"1.Balloon valvotomy may be reasonable in asymptomatic adolescent and young adult patients with pulmonic stenosis and an RV–to–pulmonary artery peak-to-peak gradient 30 to 39 mm Hg at catheterization.(Level of Evidence: C) "
Recommendations For Pulmonary Valvuloplasty
According to 2011, Indications for Cardiac Catheterization and Intervention in Pediatric Cardiac Disease, A Scientific Statement From the American Heart Association.[68]
"1. Pulmonary valvuloplasty is indicated for a patient with critical valvar pulmonary stenosis (defined as pulmonary stenosis present at birth with cyanosis and evidence of patent ductus arteriosus dependency), valvar pulmonic stenosis, and a peak-to-peak catheter gradient or echocardiographic peak instantaneous gradient of >40 mm Hg or clinically significant pulmonary valvar obstruction in the presence of RV dysfunction.(Level of Evidence: A) "
"1. It is reasonable to perform pulmonary valvuloplasty on a patient with valvar pulmonic stenosis who meets the above criteria in the setting of a dysplastic pulmonary valve.(Level of Evidence: C) "
"2. It is reasonable to perform pulmonary valvuloplasty in newborns with pulmonary valve atresia and intact ventricular septum who have favorable anatomy that includes the exclusion of RV-dependent coronary circulation.(Level of Evidence: C) "
"1. Pulmonary valvuloplasty may be considered as a palliative procedure in a patient with complex cyanotic CHD, including some rare cases of tetralogy of Fallot.(Level of Evidence: C) "
"1. Pulmonary valvuloplasty should not be performed in patients with pulmonary atresia and RV-dependent coronary circulation.(Level of Evidence: B) "
Prevention
Endocarditis prophylaxis is not recommended in patients with pulmonary stenosis, except in patients with valvular prosthesis.[69]
Participation In Sports
According to 2005 Task Force 2: Congenital Heart Disease, guidelines for participation in sports are as follows:[70]
Pulmonary valve stenosis in untreated patients
"1.Athletes with a peak systolic gradient less than 40 mm Hg and normal right ventricular function can participate in all competitive sports if no symptoms are present. Annual re-evaluation is recommended. "
"2.Athletes with a peak systolic gradient greater than 40 mm Hg can participate in low-intensity competitive sports (classes IA and IB). Patients in this category usually are referred for balloon valvuloplasty or operative valvotomy before sports participation. "
Pulmonary valve stenosis treated by operation or balloon valvuloplasty
"1.Athletes with no or only residual mild PS and normal ventricular function without symptoms can participate in all competitive sports. Participation in sports can begin two to four weeks after balloon valvuloplasty. After operation, an interval of approximately three months is suggested before resuming sports participation. "
"2.Athletes with a persistent peak systolic gradient greater than 40 mm Hg should follow the same recommendations as those for patients before treatment."
"3.Athletes with severe pulmonary incompetence characterized by a marked right ventricular enlargement can participate in class IA and IB competitive sports."
↑Paraskevas, G.; Koutsouflianiotis, K.; Iliou, K. (2017). "The first descriptions of various anatomical structures and embryological remnants of the heart: A systematic overview". International Journal of Cardiology. 227: 674–690. doi:10.1016/j.ijcard.2016.10.077. ISSN0167-5273.
↑Cabrera A, Martinez P, Rumoroso JR, Alcibar J, Arriola J, Pastor E; et al. (1995). "Double-chambered right ventricle". Eur Heart J. 16 (5): 682–6. PMID7588901.CS1 maint: Explicit use of et al. (link) CS1 maint: Multiple names: authors list (link)
↑Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP, Guyton RA, O'Gara PT, Ruiz CE, Skubas NJ, Sorajja P, Sundt TM, Thomas JD (2014). "2014 AHA/ACC guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines". J. Am. Coll. Cardiol. 63 (22): 2438–88. doi:10.1016/j.jacc.2014.02.537. PMID24603192.
↑Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP, Guyton RA, O'Gara PT, Ruiz CE, Skubas NJ, Sorajja P, Sundt TM, Thomas JD (2014). "2014 AHA/ACC guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines". J. Am. Coll. Cardiol. 63 (22): 2438–88. doi:10.1016/j.jacc.2014.02.537. PMID24603192.
↑Pagon RA, Adam MP, Ardinger HH, Wallace SE, Amemiya A, Bean L, Bird TD, Fong CT, Mefford HC, Smith R, Stephens K, Allanson JE, Roberts AE. PMID20301303. Vancouver style error: initials (help); Missing or empty |title= (help)