Continuing Education Activity

Pulmonic stenosis is a typically benign condition in most patients. While generally non-life-threatening after the neonatal period, complications and new-onset symptoms may arise in adults requiring intervention. This activity describes the evaluation and treatment of pulmonic stenosis and highlights the role of the healthcare team in improving care for patients with this condition.

Objectives:

• Describe the pathophysiology of pulmonic stenosis.
• Review the common presentation of a patient with pulmonic stenosis.
• Identify treatment considerations and common complications of interventions for patients with pulmonic stenosis.
• Explain the importance of improving care coordination amongst the interprofessional team to improve outcomes for patients affected by pulmonic stenosis.

Introduction

Pulmonic stenosis is a defect of the pulmonic valve in which the valve is stiffened, causing an obstruction to flow. This disease is typically congenital, benign, and diagnosed in pediatric patients with potentially curative treatments. Pulmonic stenosis is also present in adults, usually in conjunction with severe cardiac structural diseases.

Etiology

Pulmonic stenosis is commonly associated with congenital structural cardiac syndromes, including tetralogy of Fallot and Noonan syndrome.[1][2][3] Maternal rubella syndrome is also a common cause of congenital pulmonic stenosis, albeit it is not a genetic-based defect.[4][5] The onset of symptomatic pulmonic stenosis in adults may be seen in pregnancy of patients with undiagnosed pulmonic stenosis, or patients suffering from an underlying carcinoid syndrome.[6][7][8] Furthermore, patients with rheumatic heart disease, previous cardiothoracic surgeries, or a cardiac tumor may acquire pulmonic stenosis.

Epidemiology

Pulmonic stenosis accounts for 7%-10% of the congenital heart diseases.[9][10] There is a slight female predominance, and 2% of familial occurrences are without a genetic cause.[11]

Pathophysiology

Isolated pulmonic stenosis is divided in to valvular, subvalvular, and supravalvular obstruction.

Valvular pulmonic stenosis is the most common type. In typical valvular disease, the commissures are partially fused, and leaflets are thin. This structural anomaly results in a dome-shaped or conical outlet seen during systole.[12] Less commonly, the pulmonic valves can be dysplastic, thickened, and without fusion. The associated hypoplastic annulus and proximal pulmonary artery are common in atypical presentations and are also associated with Noonan syndrome.[13] The atypical presentation generally requires intervention in the early years of life. Bicuspid valves are associated with tetralogy of Fallot, while other variations in leaflet quantities, such as quadricuspid valves, have also been reported.[13]

Subvavular pulmonic stenosis is a defect obstructing the infundibular region. A primary cause of fibromuscular narrowing of the right ventricular outflow tract may be associated with a double-chambered right ventricle or tetralogy of Fallot.[14] Secondary causes of subvalvular pulmonic stenosis may be a result of primary valvular stenosis, inducing hypertrophy of the right ventricle. Secondary stenosis often regresses with valvotomy or valvuloplasty.[14][15][16]

Supravalvular pulmonic stenosis, also known as peripheral pulmonary stenosis, is a functional obstruction originating from the pulmonary artery. The blockage may occur at the main artery, bifurcation point, at distal branches of the pulmonary artery, or any combination thereof. Supravalvular stenosis is associated with structural defects of atrial septal defects, ventricular septal defects, patent ductus arteriosus, and tetralogy of Fallot. Supravalvular stenosis may also be a result of surgical repair of transposition of the great arteries.

History and Physical

Most patients with pulmonic stenosis are asymptomatic, which may lead to a missed diagnosis until an insult occurs. Symptomatic patients typically experience dyspnea on exertion or associated fatigue, depending on the severity of obstruction and cardiac compensatory reserve. Rarely, patients can experience angina or sudden cardiac arrest. In patients with an associated septal defect, the patient may present with signs of cyanosis.

A physical exam may reveal multiple signs of pulmonic stenosis, depending on severity and practitioner skill. Cardiac examination may reveal a left parasternal heave, secondary to right ventricular hypertrophy. Auscultation at the left upper sternal border may reveal a systolic ejection murmur radiating to the back.[17] Furthermore, there may be an associated ejection click and a split S2, rising from a delay in pulmonary closing.[18][19] Finally, pulmonic auscultation may be associated with a 4th heart sound and tricuspid regurgitation.[20][21]

Evaluation

Evaluation of pulmonic stenosis is best completed using echocardiography, due to its superior visualization of the pulmonic valve and surrounding structures.[22][23][24][25] A transthoracic echocardiogram is sufficient in most cases. Transesophageal echocardiography should be reserved for suboptimal views or when particularly assessing for endocarditis.[26][27]

Doppler studies using echocardiography provides flow gradients, which is used to grade severity. Guidelines from the European Association of Echocardiography, the American Society of Echocardiography, the American Heart Association, and American College of Cardiology (AHA/ACC) and the European Society of Cardiology have been summarized below.[22][23][28][29][30][31][32]

• Mild stenosis: Peak doppler gradient across the valve <36 mm Hg, doppler jet velocity <3m/sec, or peak doppler gradient <30 mm Hg.
• Moderate stenosis: Peak doppler gradient across the valve 36 to 64 mm Hg, doppler jet velocity 3 m/sec to 4m/sec, or peak doppler gradient 30 to 50 mm Hg.
• Severe stenosis: Peak doppler gradient across the valve >64 mm Hg, doppler jet velocity >4m/sec, or peak doppler gradient >50 mm Hg.

Pulmonic stenosis may be interpreted through electrocardiography, despite not being diagnostic. Criteria supporting right ventricular hypertrophy correlates well with the severity of the disease. Right axis deviation may also be seen in mild disease, while prominent R waves in V1 and R waves in AVR are more likely seen in severe cases.

Cardiac catheterization and pulmonary angiography are typically not required for the diagnosis of pulmonic stenosis due to echocardiography's efficacy and safety profile. Cardiac magnetic resonance imaging (CMR) is a viable alternative to echocardiography. In the setting of suboptimal echocardiographic viewing or complicated anatomy, cardiac magnetic resonance imaging may assist in proper diagnosis.[33][34] CMR also provides a measurement of the right ventricular volume, right ventricular function, and pulmonary artery blood flow.[35][36][37] Cardiac computed tomography (CCT) may be substituted for patients who cannot undergo CMR.

The sensitivity of plain film x-rays is not sufficient to diagnose pulmonic stenosis. Radiographic evidence of pulmonic stenosis is supported by the prominence of the pulmonary arteries or a prominent right heart border.

Treatment / Management

The American Heart Association and American College of Cardiology have recommended the following management plans in their 2008 guidelines:[28]

• Asymptomatic patients with peak doppler gradient <30 mm Hg can be followed up every five years with an electrocardiogram and doppler echocardiography.
• Asymptomatic patients with peak doppler gradient >30 mm Hg can be followed up every two to five years with doppler echocardiography.
• Asymptomatic patients with peak doppler gradient >60 mm Hg are recommended for balloon valvotomy.
• Symptomatic patients with a peak doppler gradient >50 mm Hg and a domed pulmonic valve are recommended for balloon valvotomy.

Surgical intervention is recommended for severe valvular stenosis with severe pulmonary regurgitation, hypoplastic pulmonary annulus, subvalvular stenosis, or supravalvular stenosis. Unfortunately, balloon valvotomy is not as effective in dysplastic valves as in domed valves, making surgery the preferred option. Balloon valvotomy may be worthwhile if peak doppler gradient is >60 mm Hg in asymptomatic patients, or if peak doppler gradient is >50 mm Hg in symptomatic patients. Surgery should also be considered in patients undergoing concurrent cardiac surgical procedures. Pulmonary artery balloon angioplasty, with optional stent placement, is an acceptable treatment for supravalvular and subvalvular pulmonic stenosis.

Differential Diagnosis

Congenital structural cardiac defects include complex congenital heart disease associated with findings of pulmonary stenosis, double-chambered right ventricle, syndrome of absent pulmonary valves, and tetralogy of Fallot. Adult-onset symptoms, excluding undiagnosed congenital causes, include rheumatic valvular heart disease and carcinoid heart disease. Acute onset of symptoms should include myocardial infarction, pulmonary embolism, right heart failure, cardiac tumor, cardiac sarcoma, sinus of Valsalva aneurysm.

Prognosis

The prognosis for most patients is excellent. Except for critical stenosis during the neonatal period, most patients will live a typical life.[38] For patients undergoing surgical revision, 67% of patients achieve 90% of maximal exercise capacity, with only 15-20% needing reintervention. 67% of reinterventions are for significant pulmonary regurgitation, and, if present, most supraventricular tachycardias (SVTs) resolved with reintervention.[39][40]

For patients undergoing balloon valvotomy, a better prognosis was seen with dome-shaped valves over dysplastic valves. After the procedure, at years 1, 3, and 6, the reintervention rate was 0%, 3.5%, and 3.5%, respectively.[41][42] Furthermore, 52% of adults were free of any symptoms.[43] Complications are generally minor but could include a vagal response, catheter induced ventricular ectopy, right bundle branch block, and transient or permanent high-grade AV nodal block.[44] A rare but serious side effect has been seen, dubbed "suicidal right ventricle," in which the infundibulum obstructs the right outflow tract; this may self-resolve or require reintervention.[43][45][46]

Patients suffering from pulmonic stenosis can also undergo virtually all dental procedures. Antibiotics are only recommended with a history of prior endocarditis or a prosthetic valve placement.[47] In pregnancy, patients should avoid vigorous exercise, especially in the second half, when they have moderate or severe gradients. Finally, in athletes with mild stenosis and gradients less than 50 mm Hg, there are no activity limitations; more severe cases should only participate in low-intensity competitive sports.

Complications

Complications of pulmonic stenosis are rare. Infective endocarditis is possible; however, it is the lowest likelihood of all valvular pathologies at 0.38 per 10,000 person-years.[48][49] Other complications include arrhythmias, typically as premature atrial contractions, premature ventricular contractions, and ventricular couplets.[50][51][52]

Consultations

In the setting of pregnancy, a high-risk obstetrician should be consulted as the hemodynamic changes associated with pregnancy can exacerbate pulmonic stenosis symptoms. Cardiology consultation for a pregnant patient may be warranted if the symptoms are severe. Consult of a pediatric cardiologist is warranted for newborns experiencing symptoms of pulmonic stenosis. Depending on the severity, pediatric critical care may also be necessary. In cases of suspected symptomatic pulmonic stenosis in an adult, a cardiology consult may be warranted.

Deterrence and Patient Education

Parents of patients diagnosed with pulmonic stenosis should be educated about complications and treatments available to pediatrics patients. Adult patients, especially those who are planning to become pregnant, should be educated about the risk of such decisions exacerbating their underlying condition.

Enhancing Healthcare Team Outcomes

An interprofessional team approach will ensure the best outcome during pregnancy and labor for patients with pulmonic stenosis. Obstetricians and cardiologists should be in communication for the affected mother's health, as well as with a pediatric intensivist and cardiologist for the affected neonate.

Review Questions

• Access free multiple choice questions on this topic.
• Comment on this article.

References

1.

Balzer D. Pulmonary Valve Replacement for Tetralogy of Fallot. Methodist Debakey Cardiovasc J. 2019 Apr-Jun;15(2):122-132. [PMC free article: PMC6668735] [PubMed: 31384375]

2.

Hill G. Repair and follow-up of Tetralogy of Fallot with pulmonary stenosis. Congenit Heart Dis. 2013 Mar-Apr;8(2):174-7. [PubMed: 23448360]

3.

Anderson K, Cnota J, James J, Miller EM, Parrott A, Pilipenko V, Weaver KN, Shikany A. Prevalence of Noonan spectrum disorders in a pediatric population with valvar pulmonary stenosis. Congenit Heart Dis. 2019 Mar;14(2):264-273. [PubMed: 30556322]

4.

Yazigi A, De Pecoulas AE, Vauloup-Fellous C, Grangeot-Keros L, Ayoubi JM, Picone O. Fetal and neonatal abnormalities due to congenital rubella syndrome: a review of literature. J Matern Fetal Neonatal Med. 2017 Feb;30(3):274-278. [PubMed: 27002428]

5.

Khanra D, Shrivastava Y, Duggal B, Soni S. Congenital supravalvular and subvalvular pulmonary stenosis with hypoplastic pulmonary annulus associated with congenital rubella syndrome. BMJ Case Rep. 2019 Jul 10;12(7) [PMC free article: PMC6626474] [PubMed: 31296628]

6.

Simula DV, Edwards WD, Tazelaar HD, Connolly HM, Schaff HV. Surgical pathology of carcinoid heart disease: a study of 139 valves from 75 patients spanning 20 years. Mayo Clin Proc. 2002 Feb;77(2):139-47. [PubMed: 11838647]

7.

Karimi A, Pourafshar N, Fudge JC. Pulmonary and tricuspid valvuloplasty in carcinoid heart disease. Catheter Cardiovasc Interv. 2018 Jun;91(7):E68-E71. [PubMed: 28029208]

8.

Nguyen A, Schaff HV, Abel MD, Luis SA, Lahr BD, Halfdanarson TR, Connolly HM. Improving outcome of valve replacement for carcinoid heart disease. J Thorac Cardiovasc Surg. 2019 Jul;158(1):99-107.e2. [PubMed: 30527716]

9.

Samánek M, Slavík Z, Zborilová B, Hrobonová V, Vorísková M, Skovránek J. Prevalence, treatment, and outcome of heart disease in live-born children: a prospective analysis of 91,823 live-born children. Pediatr Cardiol. 1989 Fall;10(4):205-11. [PubMed: 2687820]

10.

Stephensen SS, Sigfusson G, Eiriksson H, Sverrisson JT, Torfason B, Haraldsson A, Helgason H. Congenital cardiac malformations in Iceland from 1990 through 1999. Cardiol Young. 2004 Aug;14(4):396-401. [PubMed: 15680046]

11.

CAMPBELL M. Factors in the aetiology of pulmonary stenosis. Br Heart J. 1962 Sep;24(5):625-32. [PMC free article: PMC1017928] [PubMed: 14018144]

12.

Snellen HA, Hartman H, Buis-Liem TN, Kole EH, Rohmer J. Pulmonic stenosis. Circulation. 1968 Jul;38(1 Suppl):93-101. [PubMed: 4889601]

13.

Linde LM, Turner SW, Sparkes RS. Pulmonary valvular dysplasia. A cardiofacial syndrome. Br Heart J. 1973 Mar;35(3):301-4. [PMC free article: PMC458606] [PubMed: 4692662]

14.

Robertson M, Benson LN, Smallhorn JS, Musewe N, Freedom RM, Moes CA, Burrows P, Johnston AE, Burrows FA, Rowe RD. The morphology of the right ventricular outflow tract after percutaneous pulmonary valvotomy: long term follow up. Br Heart J. 1987 Sep;58(3):239-44. [PMC free article: PMC1216443] [PubMed: 3663423]

15.

Kumar M, Turrentine MW, Rodefeld MD, Bell T, Brown JW. Right Ventricular Outflow Tract Reconstruction With a Polytetrafluoroethylene Monocusp Valve: A 20-Year Experience. 2016 SummerSemin Thorac Cardiovasc Surg. 28(2):463-470. [PubMed: 28043462]

16.

Cheatham SL, Holzer RJ, Chisolm JL, Cheatham JP. The Medtronic Melody® transcatheter pulmonary valve implanted at 24-mm diameter--it works. Catheter Cardiovasc Interv. 2013 Nov 01;82(5):816-23. [PubMed: 23359563]

17.

Fitzgerald KP, Lim MJ. The pulmonary valve. Cardiol Clin. 2011 May;29(2):223-7. [PubMed: 21459245]

18.

Hultgren HN, Reeve R, Cohn K, McLeod R. The ejection click of valvular pulmonic stenosis. Circulation. 1969 Nov;40(5):631-40. [PubMed: 5377205]

19.

Stern J, Delman AJ. Normal splitting of the second heart sound in significant valvular pulmonic stenosis. Am Heart J. 1968 Jul;76(1):13-7. [PubMed: 5659268]

20.

Hayes CJ, Gersony WM, Driscoll DJ, Keane JF, Kidd L, O'Fallon WM, Pieroni DR, Wolfe RR, Weidman WH. Second natural history study of congenital heart defects. Results of treatment of patients with pulmonary valvar stenosis. Circulation. 1993 Feb;87(2 Suppl):I28-37. [PubMed: 8425320]

21.

Fathallah M, Krasuski RA. Pulmonic Valve Disease: Review of Pathology and Current Treatment Options. Curr Cardiol Rep. 2017 Sep 16;19(11):108. [PubMed: 28916901]

22.

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., American College of Cardiology/American Heart Association Task Force on Practice Guidelines. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014 Jun 10;63(22):e57-185. [PubMed: 24603191]

23.

Baumgartner H, Hung J, Bermejo J, Chambers JB, Evangelista A, Griffin BP, Iung B, Otto CM, Pellikka PA, Quiñones M., American Society of Echocardiography. European Association of Echocardiography. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr. 2009 Jan;22(1):1-23; quiz 101-2. [PubMed: 19130998]

24.

Weyman AE, Hurwitz RA, Girod DA, Dillon JC, Feigenbaum H, Green D. Cross-sectional echocardiographic visualization of the stenotic pulmonary valve. Circulation. 1977 Nov;56(5):769-74. [PubMed: 912836]

25.

Lima CO, Sahn DJ, Valdes-Cruz LM, Goldberg SJ, Barron JV, Allen HD, Grenadier E. Noninvasive prediction of transvalvular pressure gradient in patients with pulmonary stenosis by quantitative two-dimensional echocardiographic Doppler studies. Circulation. 1983 Apr;67(4):866-71. [PubMed: 6825241]

26.

Warnes CA, Williams RG, Bashore TM, Child JS, Connolly HM, Dearani JA, Del Nido P, Fasules JW, Graham TP, Hijazi ZM, Hunt SA, King ME, Landzberg MJ, Miner PD, Radford MJ, Walsh EP, Webb GD. ACC/AHA 2008 Guidelines for the Management of Adults with Congenital Heart Disease: Executive Summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to develop guidelines for the management of adults with congenital heart disease). Circulation. 2008 Dec 02;118(23):2395-451. [PubMed: 18997168]

27.

Miranda WR, Connolly HM, DeSimone DC, Phillips SD, Wilson WR, Sohail MR, Steckelberg JM, Baddour LM. Infective Endocarditis Involving the Pulmonary Valve. Am J Cardiol. 2015 Dec 15;116(12):1928-31. [PubMed: 26611123]

28.

Warnes CA, Williams RG, Bashore TM, Child JS, Connolly HM, Dearani JA, del Nido P, Fasules JW, Graham TP, Hijazi ZM, Hunt SA, King ME, Landzberg MJ, Miner PD, Radford MJ, Walsh EP, Webb GD. ACC/AHA 2008 Guidelines for the Management of Adults with Congenital Heart Disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to develop guidelines on the management of adults with congenital heart disease). Circulation. 2008 Dec 02;118(23):e714-833. [PubMed: 18997169]

29.

Baumgartner H, Bonhoeffer P, De Groot NM, de Haan F, Deanfield JE, Galie N, Gatzoulis MA, Gohlke-Baerwolf C, Kaemmerer H, Kilner P, Meijboom F, Mulder BJ, Oechslin E, Oliver JM, Serraf A, Szatmari A, Thaulow E, Vouhe PR, Walma E., Task Force on the Management of Grown-up Congenital Heart Disease of the European Society of Cardiology (ESC). Association for European Paediatric Cardiology (AEPC). ESC Committee for Practice Guidelines (CPG). ESC Guidelines for the management of grown-up congenital heart disease (new version 2010). Eur Heart J. 2010 Dec;31(23):2915-57. [PubMed: 20801927]

30.

Zaidi A, Ionescu A, Sharma R, Heatley M. Echocardiographic surveillance of aortic valve stenosis: towards a standardized approach. J Heart Valve Dis. 2012 Nov;21(6):707-13. [PubMed: 23409349]

31.

Fernando RJ, Garner C, Slaughter TF. A Review of the 2017 American Society of Echocardiography Guidelines for Evaluation of Aortic Stenosis: Considerations for Perioperative Echocardiography. J Cardiothorac Vasc Anesth. 2018 Aug;32(4):1800-1814. [PubMed: 29735221]

32.

Galiè N, Humbert M, Vachiery JL, Gibbs S, Lang I, Torbicki A, Simonneau G, Peacock A, Vonk Noordegraaf A, Beghetti M, Ghofrani A, Gomez Sanchez MA, Hansmann G, Klepetko W, Lancellotti P, Matucci M, McDonagh T, Pierard LA, Trindade PT, Zompatori M, Hoeper M., ESC Scientific Document Group. 2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension: The Joint Task Force for the Diagnosis and Treatment of Pulmonary Hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS): Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC), International Society for Heart and Lung Transplantation (ISHLT). Eur Heart J. 2016 Jan 01;37(1):67-119. [PubMed: 26320113]

33.

Fratz S, Hess J, Schwaiger M, Martinoff S, Stern HC. More accurate quantification of pulmonary blood flow by magnetic resonance imaging than by lung perfusion scintigraphy in patients with fontan circulation. Circulation. 2002 Sep 17;106(12):1510-3. [PubMed: 12234957]

34.

Kutty S, Rathod RH, Danford DA, Celermajer DS. Role of imaging in the evaluation of single ventricle with the Fontan palliation. Heart. 2016 Feb;102(3):174-83. [PubMed: 26567230]

35.

Sridharan S, Derrick G, Deanfield J, Taylor AM. Assessment of differential branch pulmonary blood flow: a comparative study of phase contrast magnetic resonance imaging and radionuclide lung perfusion imaging. Heart. 2006 Jul;92(7):963-8. [PMC free article: PMC1860721] [PubMed: 16775104]

36.

Steeden JA, Atkinson D, Hansen MS, Taylor AM, Muthurangu V. Rapid flow assessment of congenital heart disease with high-spatiotemporal-resolution gated spiral phase-contrast MR imaging. Radiology. 2011 Jul;260(1):79-87. [PMC free article: PMC3121014] [PubMed: 21415248]

37.

Roman KS, Kellenberger CJ, Farooq S, MacGowan CK, Gilday DL, Yoo SJ. Comparative imaging of differential pulmonary blood flow in patients with congenital heart disease: magnetic resonance imaging versus lung perfusion scintigraphy. Pediatr Radiol. 2005 Mar;35(3):295-301. [PubMed: 15490145]

38.

Shaath G, Al Mutairi M, Tamimi O, Alakhfash A, Abolfotouh M, Alhabshan F. Predictors of reintervention in neonates with critical pulmonary stenosis or pulmonary atresia with intact ventricular septum. Catheter Cardiovasc Interv. 2012 Mar 01;79(4):659-64. [PubMed: 21954133]

39.

Roos-Hesselink JW, Meijboom FJ, Spitaels SE, vanDomburg RT, vanRijen EH, Utens EM, Bogers AJ, Simoons ML. Long-term outcome after surgery for pulmonary stenosis (a longitudinal study of 22-33 years). Eur Heart J. 2006 Feb;27(4):482-8. [PubMed: 16361324]

40.

Nielsen EA, Hjortdal VE. Surgically treated pulmonary stenosis: over 50 years of follow-up. Cardiol Young. 2016 Jun;26(5):860-6. [PubMed: 26403466]

41.

Sehar T, Qureshi AU, Kazmi U, Mehmood A, Hyder SN, Sadiq M. Balloon valvuloplasty in dysplastic pulmonary valve stenosis: immediate and intermediate outcomes. J Coll Physicians Surg Pak. 2015 Jan;25(1):16-21. [PubMed: 25604363]

42.

Parent JJ, Ross MM, Bendaly EA, Breinholt JP. Results of pulmonary balloon valvuloplasty persist and improve at late follow-up in isolated pulmonary valve stenosis. Cardiol Young. 2017 Oct;27(8):1566-1570. [PubMed: 28651667]

43.

Taggart NW, Cetta F, Cabalka AK, Hagler DJ. Outcomes for balloon pulmonary valvuloplasty in adults: comparison with a concurrent pediatric cohort. Catheter Cardiovasc Interv. 2013 Nov 01;82(5):811-5. [PubMed: 23613310]

44.

Rao PS. Percutaneous balloon pulmonary valvuloplasty: state of the art. Catheter Cardiovasc Interv. 2007 Apr 01;69(5):747-63. [PubMed: 17330270]

45.

Ben-Shachar G, Cohen MH, Sivakoff MC, Portman MA, Riemenschneider TA, Van Heeckeren DW. Development of infundibular obstruction after percutaneous pulmonary balloon valvuloplasty. J Am Coll Cardiol. 1985 Mar;5(3):754-6. [PubMed: 3156173]

46.

Ahmadi A, Sabri M. Percutaneous balloon valvuloplasty inpatients with pulmonary valve stenosis: a single center experiment. J Pak Med Assoc. 2012 Mar;62(3 Suppl 2):S58-61. [PubMed: 22768462]

47.

Wilson W, Taubert KA, Gewitz M, Lockhart PB, Baddour LM, Levison M, Bolger A, Cabell CH, Takahashi M, Baltimore RS, Newburger JW, Strom BL, Tani LY, Gerber M, Bonow RO, Pallasch T, Shulman ST, Rowley AH, Burns JC, Ferrieri P, Gardner T, Goff D, Durack DT., American Heart Association. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. J Am Dent Assoc. 2008 Jan;139 Suppl:3S-24S. [PubMed: 18167394]

48.

Gersony WM, Hayes CJ, Driscoll DJ, Keane JF, Kidd L, O'Fallon WM, Pieroni DR, Wolfe RR, Weidman WH. Bacterial endocarditis in patients with aortic stenosis, pulmonary stenosis, or ventricular septal defect. Circulation. 1993 Feb;87(2 Suppl):I121-6. [PubMed: 8425318]

49.

Gersony WM, Hayes CJ. Bacterial endocarditis in patients with pulmonary stenosis, aortic stenosis, or ventricular septal defect. Circulation. 1977 Aug;56(1 Suppl):I84-7. [PubMed: 872351]

50.

Wolfe RR, Driscoll DJ, Gersony WM, Hayes CJ, Keane JF, Kidd L, O'Fallon WM, Pieroni DR, Weidman WH. Arrhythmias in patients with valvar aortic stenosis, valvar pulmonary stenosis, and ventricular septal defect. Results of 24-hour ECG monitoring. Circulation. 1993 Feb;87(2 Suppl):I89-101. [PubMed: 8425327]

51.

Cuypers JA, Menting ME, Opić P, Utens EM, Helbing WA, Witsenburg M, van den Bosch AE, van Domburg RT, Baart SJ, Boersma E, Meijboom FJ, Bogers AJ, Roos-Hesselink JW. The unnatural history of pulmonary stenosis up to 40 years after surgical repair. Heart. 2017 Feb 15;103(4):273-279. [PubMed: 27515953]

52.

Ruckdeschel ES, Schuller J, Nguyen DT. Ventricular Tachycardia in Congenital Pulmonary Stenosis. Card Electrophysiol Clin. 2016 Mar;8(1):205-9. [PubMed: 26920196]

Disclosure: Joseph Heaton declares no relevant financial relationships with ineligible companies.

Disclosure: Chris Kyriakopoulos declares no relevant financial relationships with ineligible companies.