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Mitral Stenosis

  • Author: Claudia Dima, MD, FACC; Chief Editor: Richard A Lange, MD, MBA  more...
 
Updated: Nov 06, 2014
 

Background

Mitral stenosis (MS) is characterized by obstruction to left ventricular inflow at the level of mitral valve due to structural abnormality of the mitral valve apparatus. The most common cause of mitral stenosis is rheumatic fever. The association of atrial septal defect with rheumatic mitral stenosis is called Lutembacher syndrome.

Stenosis of the mitral valve typically occurs decades after the episode of acute rheumatic carditis. Acute insult leads to formation of multiple inflammatory foci (Aschoff bodies, perivascular mononuclear infiltrate) in the endocardium and myocardium. Small vegetations along the border of the valves may also be observed. With time, the valve apparatus becomes thickened, calcified, and contracted, and commissural adhesion occurs, ultimately resulting in stenosis.

Whether the progression of valve damage is due to hemodynamic injury of the already affected valve apparatus or to the chronic inflammatory nature of the rheumatic process is unclear.

Other causes

Other, less common etiologies for mitral stenosis include malignant carcinoid disease, systemic lupus erythematosus, rheumatoid arthritis, mucopolysaccharidoses of the Hunter-Hurler phenotype, Fabry disease, Whipple disease, and methysergide therapy. Congenital mitral stenosis can also occur.

A number of conditions can simulate the physiology of mitral stenosis: severe nonrheumatic mitral annular calcification, infective endocarditis with large vegetation, left atrial myxoma, ball valve thrombus, and cor triatriatum.

Indeed, a study by Iwataki et al indicated that in patients with degenerative aortic stenosis, calcific extension to the mitral valve, causing mitral annular/leaflet calcification, can result in nonrheumatic mitral stenosis. Using real-time three-dimensional (3D) transesophageal echocardiography in 101 patients with degenerative aortic stenosis and 26 control subjects, the investigators found an average decrease of 45% in the effective mitral annular area of the patients with degenerative aortic stenosis, as well as a significant reduction in the maximal anterior and posterior leaflet opening angle. Consequently, a significant decrease in the mitral valve area in these patients was found, with an area of less than 1.5 cm2 detected in 24 of them (24%).[1]

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Pathophysiology

The normal mitral valve orifice area is approximately 4-6 cm2. As the orifice size decreases, the pressure gradient across the mitral valve increases to maintain adequate flow.

Patients will not experience valve-related symptoms until the valve area is 2-2.5 cm2 or less, at which point moderate exercise or tachycardia may result in exertional dyspnea from the increased transmitral gradient and left atrial pressure.

Severe mitral stenosis occurs with a valve area of less than 1 cm2. As the valve progressively narrows, the resting diastolic mitral valve gradient, and hence left atrial pressure, increases. This leads to transudation of fluid into the lung interstitium and dyspnea at rest or with minimal exertion. Hemoptysis may occur if the bronchial veins rupture and left atrial dilatation increases the risk for atrial fibrillation and subsequent thromboembolism.

Pulmonary hypertension may develop as a result of (1) retrograde transmission of left atrial pressure, (2) pulmonary arteriolar constriction, (3) interstitial edema, or (4) obliterative changes in the pulmonary vascular bed (intimal hyperplasia and medial hypertrophy). As pulmonary arterial pressure increases, right ventricular dilation and tricuspid regurgitation may develop, leading to elevated jugular venous pressure, liver congestion, ascites, and pedal edema.

Left ventricular end-diastolic pressure and cardiac output are usually normal in the person with isolated mitral stenosis. As the severity of stenosis increases, the cardiac output becomes subnormal at rest and fails to increase during exercise. Approximately one third of patients with rheumatic mitral stenosis have depressed left ventricular systolic function as a result of chronic rheumatic myocarditis. The presence of concomitant mitral regurgitation, systemic hypertension, aortic stenosis, or myocardial infarction can also adversely affect left ventricular function and cardiac output.

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Epidemiology

Frequency

United States

The prevalence of rheumatic disease in developed nations is steadily declining with an estimated incidence of 1 in 100,000.

International

The prevalence of rheumatic disease is higher in developing nations than in the United States.[2] In India, for example, the prevalence is approximately 100-150 cases per 100,000, and in Africa the prevalence is 35 cases per 100,000.

Mortality/Morbidity

Mitral stenosis is a progressive disease consisting of a slow, stable course in the early years followed by an accelerated course later in life. Typically, there is a latent period of 20-40 years from the occurrence of rheumatic fever to the onset of symptoms. Once symptoms develop, it is almost a decade before they become disabling. In some geographic areas, mitral stenosis progresses more rapidly, presumably due to either a more severe rheumatic insult or repeated episodes of rheumatic carditis due to new streptococcal infections, which results in severe symptomatic mitral stenosis in the late teens and early 20s.

In the asymptomatic or minimally symptomatic patient, survival is greater than 80% at 10 years. When limiting symptoms occur, 10-year survival is less than 15% in the patient with untreated mitral stenosis. When severe pulmonary hypertension develops, mean survival is less than 3 years. Most (60%) patients with severe untreated mitral stenosis die of progressive pulmonary or systemic congestion, but others may suffer systemic embolism (20-30%), pulmonary embolism (10%), or infection (1-5%).

Sex

Two thirds of all patients with rheumatic mitral stenosis are female.

Age

The onset of symptoms usually occurs between the third and fourth decade of life.

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Contributor Information and Disclosures
Author

Claudia Dima, MD, FACC Interventional Cardiology

Disclosure: Nothing to disclose.

Coauthor(s)

Kenneth B Desser, MD † Former Clinical Professor, Director of Cardiology Fellowship, Banner Good Samaritan Medical Center

Disclosure: Nothing to disclose.

Specialty Editor Board

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.

Steven J Compton, MD, FACC, FACP, FHRS Director of Cardiac Electrophysiology, Alaska Heart Institute, Providence and Alaska Regional Hospitals

Steven J Compton, MD, FACC, FACP, FHRS is a member of the following medical societies: American College of Physicians, American Heart Association, American Medical Association, Heart Rhythm Society, Alaska State Medical Association, American College of Cardiology

Disclosure: Nothing to disclose.

Chief Editor

Richard A Lange, MD, MBA President, Texas Tech University Health Sciences Center, Dean, Paul L Foster School of Medicine

Richard A Lange, MD, MBA is a member of the following medical societies: Alpha Omega Alpha, American College of Cardiology, American Heart Association, Association of Subspecialty Professors

Disclosure: Nothing to disclose.

Additional Contributors

L Michael Prisant, MD, FACC, FAHA Cardiologist, Emeritus Professor of Medicine, Medical College of Georgia, Georgia Regents University

L Michael Prisant, MD, FACC, FAHA is a member of the following medical societies: American College of Cardiology, American College of Chest Physicians, American College of Clinical Pharmacology, American College of Forensic Examiners Institute, American College of Physicians, American Heart Association, American Medical Association

Disclosure: Received honoraria from Boehringer-Ingelheim for speaking and teaching.

Acknowledgements

The authors and editors of Medscape Drugs & Diseases gratefully acknowledge the contributions of previous authors Holger P Salazar, MD, Senthil Nachimuthu, MD, FACP, and Kiruthika Balasundaram, MBBS, to the development and writing of this article.

References
  1. Iwataki M, Takeuchi M, Otani K, et al. Calcific extension towards the mitral valve causes non-rheumatic mitral stenosis in degenerative aortic stenosis: real-time 3D transoesophageal echocardiography study. Open Heart. 2014. 1(1):e000136. [Medline]. [Full Text].

  2. Marcus RH, Sareli P, Pocock WA, et al. The spectrum of severe rheumatic mitral valve disease in a developing country. Correlations among clinical presentation, surgical pathologic findings, and hemodynamic sequelae. Ann Intern Med. 1994 Feb 1. 120(3):177-83. [Medline].

  3. Henri C, Pierard LA, Lancellotti P, Mongeon FP, Pibarot P, Basmadjian AJ. Exercise Testing and Stress Imaging in Valvular Heart Disease. Can J Cardiol. 2014 Sep. 30(9):1012-1026. [Medline].

  4. Wunderlich NC, Beigel R, Siegel RJ. Management of mitral stenosis using 2D and 3D echo-Doppler imaging. JACC Cardiovasc Imaging. 2013 Nov. 6(11):1191-205. [Medline].

  5. Bruce CJ, Nishimura RA. Newer advances in the diagnosis and treatment of mitral stenosis. Curr Probl Cardiol. 1998 Mar. 23(3):125-92. [Medline].

  6. Schlosshan D, Aggarwal G, Mathur G, Allan R, Cranney G. Real-time 3D transesophageal echocardiography for the evaluation of rheumatic mitral stenosis. JACC Cardiovasc Imaging. 2011 Jun. 4(6):580-8. [Medline].

  7. [Guideline] Nishimura RA, Otto CM, Bonow RO, et al. 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. [Medline]. [Full Text].

  8. [Guideline] Gerber MA, Baltimore RS, Eaton CB, Gewitz M, Rowley AH, Shulman ST, et al. Prevention of rheumatic fever and diagnosis and treatment of acute Streptococcal pharyngitis: a scientific statement from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee of the Council on Cardiovascular Disease in the Young, the Interdisciplinary Council on Functional Genomics and Translational Biology, and the Interdisciplinary Council on Quality of Care and Outcomes Research: endorsed by the American Academy of Pediatrics. Circulation. 2009 Mar 24. 119(11):1541-51. [Medline].

  9. Antonini-Canterin F, Moura LM, Enache R, Leiballi E, Pavan D, Piazza R. Effect of hydroxymethylglutaryl coenzyme-a reductase inhibitors on the long-term progression of rheumatic mitral valve disease. Circulation. 2010 May 18. 121(19):2130-6. [Medline].

  10. [Guideline] Nishimura RA, Carabello BA, Faxon DP, et al. ACC/AHA 2008 Guideline update on valvular heart disease: focused update on infective endocarditis: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol. 2008 Aug 19. 52(8):676-85. [Medline].

  11. [Guideline] Vahanian A, Alfieri O, Andreotti F, et al. Guidelines on the management of valvular heart disease (version 2012): The Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC) and the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2012 Oct. 33(19):2451-96. [Medline].

  12. Wann LS, Curtis AB, Ellenbogen KA, et al. 2011 ACCF/AHA/HRS focused update on the management of patients with atrial fibrillation (update on dabigatran): a report of the American College of Cardiology Foundation/American Heart Association Task Force on practice guidelines. J Am Coll Cardiol. 2011 Mar 15. 57(11):1330-7. [Medline].

  13. Feldman T. Rheumatic Mitral Stenosis. Curr Treat Options Cardiovasc Med. 2000 Apr. 2(2):93-104. [Medline].

  14. Rahimtoola SH. Choice of Prosthetic Heart Valve in Adults An Update. J Am Coll Cardiol. 2010 Jun 1. 55(22):2413-2426. [Medline].

  15. Holmes DR Jr, Mack MJ. Transcatheter valve therapy a professional society overview from the american college of cardiology foundation and the society of thoracic surgeons. J Am Coll Cardiol. 2011 Jul 19. 58(4):445-55. [Medline].

  16. Horstkotte D, Niehues R, Strauer BE. Pathomorphological aspects, aetiology and natural history of acquired mitral valve stenosis. Eur Heart J. 1991 Jul. 12 Suppl B:55-60. [Medline].

 
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M-mode across the mitral valve showing a flat E-F slope resulting from elevated left atrial pressure throughout diastole due to a significant gradient across the mitral valve. Increased thickness and calcification of anterior leaflet of the mitral valve and decreased opening of the anterior and posterior leaflets in diastole are also shown.
Parasternal long-axis view demonstrating calcification and doming in diastole of the anterior valve leaflet and mild restriction in the opening of posterior mitral valve leaflet.
Apical 4-chamber view demonstrating restricted opening of the anterior and posterior mitral valve leaflet with diastolic doming of anterior leaflet with left atrial enlargement.
Transesophageal echocardiogram with continuous wave Doppler interrogation across the mitral valve demonstrating an increased mean gradient of 16 mm Hg consistent with severe mitral stenosis.
Apical 4-chamber view with color Doppler demonstrating aliasing in the atrial side of the mitral valve consistent with increased gradient across the valve. This figure also shows mitral regurgitation and left atrial enlargement.
Magnified view of the mitral valve in apical 4-chamber view revealing restricted opening of both leaflets.
Transesophageal echocardiogram in an apical 3-chamber view showing calcification and doming of the anterior mitral leaflet and restricted opening of both leaflets.
Transesophageal echocardiogram in an apical 3-chamber view with color Doppler interrogation of the mitral valve revealing aliasing, which is consistent with increased gradient across the mitral valve secondary to stenosis. Also shown in this image, a posteriorly directed jet of severe mitral regurgitation.
Table 1. Duration of Secondary Rheumatic Fever Prophylaxis
Category Duration After Last Attack Rating*
Rheumatic fever with carditis and residual heart disease (persistent valvular disease† ) 10 y or until age 40 y (whichever is longer); sometimes lifelong prophylaxis IC
Rheumatic fever with carditis but no residual heart disease (no valvular disease† ) 10 y or until age 21 y (whichever is longer) IC
Rheumatic fever without carditis 5 y or until age 21 y (whichever is longer) IC
*Rating indicates classification of recommendation and level of evidence (eg, IC indicates Class I, level of Evidence C).



†Clinical or echocardiographic evidence.



Table 2. Secondary Prevention of Rheumatic Fever (Prevention of Recurrent Attacks)
Agent Dose Mode Rating*
Benzathine penicillin G Children 27 kg (60 lb): 600,000 U



Patients >27 kg: 1,200,000 every 4 wk†



Intramuscular IA
Penicillin V 250 mg bid Oral IB
Sulfadiazine Children 27 kg: 0.5 g qd



Patients >27 kg: 1 g qd



Oral IB
Macrolide or azalide (for individuals allergic to penicillin and sulfadiazine) Variable Oral IC
*Rating indicates classification of recommendation and level of evidence (eg, IA indicates Class I, level of Evidence A).



†In high-risk situations, administration every 3 weeks is justified and recommended.



Table 3. Primary Prevention of Rheumatic Fever (Treatment of Streptococcal Tonsillopharyngitis*)
Agent Dose Mode Duration Rating
Penicillins
Penicillin V (phenoxymethyl penicillin) Children 27 kg (60 lb): 250 mg bid or tid



Patients >27 kg: 500 mg bid or tid



Oral 10 d IB
Amoxicillin 50 mg/kg qd (maximum 1 g) Oral 10 d IB
Benzathine penicillin G Children 27 kg (60 lb): 600,000 U



Patients >27 kg: 1,200,000 U



Intramuscular Once IB
For individuals allergic to penicillin
Narrow-spectrum cephalosporin (cephalexin, cefadroxil) Variable Oral 10 d IB
Clindamycin 20 mg/kg/d divided in 3 doses (maximum 1.8 g/d) Oral 10 d IIaB
Azithromycin 12 mg/kg qd (maximum 500 mg) Oral 5 d IIaB
Clarithromycin 15 mg/kg/d divided bid (maximum 250 mg bid) Oral 10 d IIaB
*Sulfonamides, trimethoprim, tetracyclines, and fluoroquinolones are not acceptable.



† Rating indicates classification of recommendation and level of evidence (eg, IB indicates Class I, level of Evidence B)



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