Mitral stenosis

13 Interesting Facts of Mitral stenosis

1. Mitral stenosis involves narrowing of mitral valve orifice, restricting blood flow from left atrium to left ventricle during diastole
2. Slowly progressive disease; many patients remain asymptomatic by readjusting their lifestyles to a more sedentary level 
3. Rheumatic fever is the most common cause 
4. Initial diagnosis is suggested by history and physical examination
5. Echocardiography is the diagnostic test of choice 
6. No known drug therapies to prevent worsening of stenosis; antibiotic prophylaxis can help prevent rheumatic fever recurrence 
7. Medical therapy, although not curative, can control the hemodynamic consequences of mitral stenosis, such as heart failure and atrial fibrillation
8. Percutaneous mitral balloon valvotomy is the therapy of choice for uncomplicated mitral stenosis 
9. Surgical management of mitral stenosis (commissurotomy or valve replacement) is indicated in severely symptomatic patients with severe mitral stenosis (mitral valve area of 1.5 cm² or smaller, stage D) who are not high-risk surgical candidates and who are not candidates for percutaneous mitral balloon valvotomy (or who have undergone failed percutaneous mitral balloon valvotomy) 
10. Atrial fibrillation, systemic embolism, stroke, and bacterial endocarditis are complications 
11. Severity of stenosis progresses in almost all patients
12. Drugs can only provide symptomatic relief and delay the need for surgery
13. Surgical management is not curative but may prolong survival

Pitfalls

• Endocarditis prophylaxis for dental procedures is reasonable only for patients at elevated risk—those with the following: 
  • Prosthetic cardiac valves
  • Prosthetic material used for cardiac valve repair (eg, annuloplasty rings and chords)
  • Previous infective endocarditis
  • Cardiac transplant with valve regurgitation due to a structurally abnormal valve
  • Unrepaired cyanotic congenital heart disease or repaired congenital heart disease, with residual shunts or valvular regurgitation at or adjacent to a prosthetic patch or prosthetic device
• Heart failure can be exacerbated with β-blocker therapy, but this is rarely a cause for stopping therapy
  • Consider temporary increases in diuretic treatment and/or a slight reduction of the β-blocker dose
  • After stabilization, make an effort to uptitrate toward the target dose

Mitral stenosis involves narrowing of mitral valve orifice, restricting blood flow from left atrium to left ventricle during diastole

Classification

• Stages of mitral stenosis, according to American Heart Association/American College of Cardiology guideline 
  • Stage A, B, C, or D based on valve anatomy and hemodynamics, hemodynamic consequences, and symptoms

Stage	Definition	Valve anatomy	Valve hemodynamics	Hemodynamic consequences	Symptoms
A	At risk of mitral stenosis	• Mild valve doming during diastole	• Normal transmitral flow velocity	• None	• None
B	Progressive mitral stenosis	• Rheumatic valve changes with commissural fusion and diastolic doming of the mitral valve leaflets • Planimetered mitral valve area more than 1.5 cm²	• Increased transmitral flow velocities • Mitral valve area more than 1.5 cm² • Diastolic pressure half-time less than 150 ms	• Mild to moderate left atrial enlargement • Normal pulmonary pressure at rest	• None
C	Asymptomatic severe mitral stenosis	• Rheumatic valve changes with commissural fusion and diastolic doming of the mitral valve leaflets • Planimetered mitral valve area 1.5 cm² or less • (Mitral valve area 1 cm² or less with very severe mitral stenosis)	• Mitral valve area 1.5 cm² or less • (Mitral valve area 1 cm² or less with very severe mitral stenosis) • Diastolic pressure half-time 150 ms or more • (Diastolic pressure half-time 220 ms or more with very severe mitral stenosis)	• Severe left atrial enlargement • Elevated pulmonary artery systolic pressure: more than 30 mm Hg	• None
D	Symptomatic severe mitral stenosis	• Rheumatic valve changes with commissural fusion and diastolic doming of the mitral valve leaflets • Planimetered mitral valve area 1.5 cm² or less	• Mitral valve area 1.5 cm² or less • (Mitral valve area 1 cm² or less with very severe mitral stenosis) • Diastolic pressure half-time 150 ms or more • (Diastolic pressure half-time 220 ms or more with very severe mitral stenosis)	• Severe left atrial enlargement • Elevated pulmonary artery systolic pressure: more than 30 mm Hg	• Decreased exercise tolerance • Exertional dyspnea

Caption: The transmitral mean pressure gradient should be obtained to further determine the hemodynamic effect of the mitral stenosis and is usually more than 5 to 10 mm Hg in severe mitral stenosis; however, due to the variability of the mean pressure gradient with heart rate and forward flow, it has not been included in the criteria for severity.

Citation: From Nishimura RA 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. 63(22):e57-185, 2014, Table 13.

Clinical Presentation

History

• Patients may be asymptomatic while at rest in the early stages
• Disease is slowly progressive; many patients remain asymptomatic by readjusting their lifestyles to a more sedentary level 
• Symptoms may include the following:
  • Dyspnea
  • Fatigue (due to decreased cardiac output)
  • Hemoptysis (due to sudden hemorrhage from rupture of thin-walled bronchial veins)
  • Chest pain
  • Weight loss
  • Hoarseness (due to left atrial enlargement and pressure on recurrent laryngeal nerve, ie, Ortner syndrome)
• Patients may present with symptoms of congestive heart failure, as follows:
  • Dyspnea on exertion
  • Orthopnea
  • Paroxysmal nocturnal dyspnea
  • Pedal/peripheral edema
• History of rheumatic fever (several years to more than 20 years prior) 
• Family history of rheumatic fever or mitral stenosis

Physical examination 

• Irregular pulse (caused by atrial fibrillation)
• Jugular venous pulse
  • Prominent a wave; a wave disappears with onset of atrial fibrillation
  • Pulsatile neck veins
• Tachypnea
• Mitral facies: cheeks with pinkish purple patches; associated with severe chronic mitral stenosis, low cardiac output, and systemic vasoconstriction
• Lung crepitation
• Apical impulse displacement (due to right ventricular hypertrophy)
• Right ventricular heave, palpable S₁ (tapping apical impulse), palpable P₂, and diastolic thrill in mitral area
• Auscultatory findings
  • Low-pitched, rough, and rumbling early diastolic murmur with presystolic accentuation during expiration; best heard over apex with bell of stethoscope in the left lateral position
  • Noncalcified mitral valve
    • Persisting murmur throughout diastole
    • Loud S₁ and opening snap
  • Calcified mitral valve
    • Murmur is difficult to hear
    • Soft or absent S₁ and opening snap
• In later stages, findings include:
  • Hepatomegaly
  • Ascites
  • Peripheral edema

Causes

• Common causes
  • Rheumatic fever is the most common cause (rheumatic mitral stenosis) 
    • Rheumatic changes are present in 99% of stenotic mitral valves surgically excised
    • Incidence of rheumatic mitral stenosis has greatly decreased in industrialized countries 
  • Degenerative calcification
    • Annular calcification of mitral valve is age related and is most commonly associated with cardiovascular risk factors and end-stage renal disease (degenerative mitral stenosis)
• Less common causes include: 
  • Congenital defect in mitral valve
  • Malignant carcinoid syndrome
  • Systemic lupus erythematosus
  • Rheumatoid arthritis
  • Whipple disease
  • Fabry disease
  • Mucopolysaccharidoses of the Hurler syndrome phenotype
  • Drugs (eg, methysergide therapy, diet drug fenfluramine)

Risk factors and/or associations

Age 

• In North America and Europe (approximately 1 case per 100,000 people), patients present with severe valve obstruction in sixth decade of life
• In Africa (approximately 35 cases per 100,000 people), severe disease often is seen in teenagers

Sex

• Two-thirds of all patients with rheumatic mitral stenosis are female 

Other risk factors/associations

• Progression is more rapid in tropical climate regions
• Low socioeconomic status correlates with untreated or undertreated streptococcal infections, favoring development of rheumatic fever; drives higher incidence of valvular disease in developing countries compared with developed countries 
• Recurrent streptococcal infection; more common in developing countries, owing to poor diagnosis and treatment of streptococcal infections

Diagnostic Procedures

• Diagnosis is typically established by history and physical examination, chest radiograph, ECG, and echocardiography
• Initial diagnosis is suggested by history and physical examination
  • History of rheumatic fever
  • Presence of typical symptoms (eg, dyspnea, fatigue, chest pain)
  • Positive auscultatory findings
• ECG
  • May reveal signs of left atrial enlargement, atrial fibrillation, or signs of right ventricular hypertrophy as disease advances
• Chest radiography
  • May demonstrate signs of left atrial enlargement; with disease progression, enlarged right ventricle and signs of pulmonary edema may be present
• Echocardiography is method of choice to diagnose mitral stenosis and to access the severity and hemodynamic consequences 
  • Exercise testing combined with Doppler echocardiography is recommended when discrepancy exists between resting echocardiographic findings and severity of clinical symptoms 
• Occasionally, cardiac catheterization can be used to evaluate mitral stenosis when there is discrepancy between clinical picture and echocardiographic findings; routine diagnostic cardiac catheterization is not recommended 

Imaging

• Echocardiography 
  • Gold standard investigation to confirm mitral stenosis
  • Transthoracic echocardiography is usually sufficient for routine management 
    • Transesophageal echocardiography may be preferred for its higher image quality to exclude atrial thrombus (eg, before percutaneous mitral balloon valvotomy or after embolic event)
  • Measures the following:
    • Degree of abnormality in valves
    • Valve area
    • Pulmonary artery pressure (elevated in mitral stenosis)
  • Detects thickening and calcification of mitral valve cusps
  • Mitral valve commissural fusion can be detected
  • Transmitral pressure gradient is high (more than 10 mm Hg)
  • Posterior aspect of mitral valve moves anteriorly during diastole
  • Doming of mitral valve leaflets may be noted during diastole
  • Left atrial clot may be noted
  • Wilkins score or mitral valvuloplasty score: valve condition is quantified according to leaflet thickness, mobility, calcification, and subvalvular thickening found on echocardiogram 
    • Useful to predict feasibility for percutaneous mitral balloon valvotomy or surgical commissurotomy 
    • Assessment of mitral valve anatomy according to Wilkins score 

Grade	Mobility	Thickening	Calcification	Subvalvular thickening
1	Highly mobile valve with only leaflet tips restricted	Leaflets near normal in thickness (4-5 mm)	A single area of increased echo brightness	Minimum thickening just below the mitral leaflets
2	Leaflet mid and base portions have normal mobility	Midleaflets normal, considerable thickening of margins (5-8 mm)	Scattered areas of brightness confined to leaflet margins	Thickening of chordal structures extending to one-third of the chordal length
3	Valve continues to move forward in diastole, mainly from the base	Thickening extended through the entire leaflet (5-8 mm)	Brightness extending into the mid-portions of the leaflets	Thickening extended to distal third of the chords
4	No or minimal forward movement of the leaflets in diastole	Considerable thickening of all leaflet tissue (more than 8-10 mm)	Extensive brightness throughout much of the leaflet tissue	Extensive thickening and shortening of all chordal structures extending down to the papillary muscles

Caption: The total score is the sum of the 4 items and ranges between 4 and 16.

Citation: From Baumgartner H et al: Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. J Am Soc Echocardiogr. 22(1):1-23; quiz 101-2, 2009, Table 5.

• Doppler echocardiography assists in assessment of pulmonary hypertension; measures pulmonary artery pressure during rest and exercise 

Functional testing

• ECG 
  • As an initial test, may suggest features associated with mitral stenosis, but echocardiography is necessary for confirmation
  • Relatively insensitive for detecting mild mitral stenosis, but does show characteristic changes with moderate to severe obstruction
  • Left atrial enlargement (P wave duration in lead II greater than 0.12 seconds and/or a P wave axis between +45° and −30°) is seen in 90% of patients with significant mitral stenosis and sinus rhythm
  • Findings are similar to those of pulmonary hypertension (eg, right axis deviation), atrial fibrillation (eg, absent P waves, irregularly irregular rate), and right ventricular hypertrophy

Differential Diagnosis

Most common

• Increased flow through anatomically normal valve
• Austin Flint murmur
• Left atrial myxoma
• Infective endocarditis
• Cor triatriatum
• Atrial septal defect

Treatment Goals

• Prevent recurrent rheumatic fever
• Relieve symptoms
• Prevent development of complications
• Control symptoms of congestive heart failure
• Treat atrial fibrillation, if present
• Prevent thrombus propagation

Admission criteria

Congestive heart failure

Pregnant women with symptoms of mitral stenosis in second or third trimester

Criteria for ICU admission

• Atrial fibrillation
  • Sustained atrial fibrillation that compromises cardiac output or leads to pulmonary congestion requires hospitalization and urgent cardioversion
• Systemic emboli
• Infective endocarditis

Recommendations for specialist referral

• Refer to cardiologist for the following:
  • All suspected cases of mitral stenosis, for baseline echocardiographic assessment
  • Pregnant patients with moderate to severe stenosis
  • Known case of mitral stenosis with dyspnea that restricts normal activities
• Refer to interventional cardiologist or cardiothoracic surgeon if invasive intervention is planned

Treatment Options

No drug therapies are known to prevent worsening of stenosis

Patients with rheumatic mitral stenosis should receive penicillin prophylaxis for β-hemolytic streptococcal infections to prevent rheumatic fever recurrence 

• Long-term prophylaxis against rheumatic fever is recommended to prevent recurrent episodes and consequent progression of the disease in patients with rheumatic heart disease 

Medical therapy, although not curative, can control hemodynamic consequences of mitral stenosis, such as heart failure and atrial fibrillation

• Options include the following: 
  • β-blockers for atrial fibrillation and heart failure
  • Calcium channel blockers for atrial fibrillation and heart failure
  • Digoxin for heart failure; consider when β-blockers and calcium channel blockers are ineffective for rate control
  • Diuretics for heart failure; consider with severe mitral stenosis, with persistent symptoms after intervention, or when intervention is not possible
  • In patients with atrial fibrillation and rheumatic mitral stenosis, vitamin K antagonist is indicated for anticoagulation 
    • For patients in sinus rhythm, oral anticoagulation is indicated in patients with history of embolism or with left atrial thrombus 
• Heart failure can be exacerbated with β-blocker therapy, but this is rarely a cause for stopping therapy
  • Consider temporary increases in diuretic treatment and/or a slight reduction of the β-blocker dose
  • After stabilization, make an effort to uptitrate toward the target dose

Percutaneous mitral balloon valvotomy is the therapy of choice for uncomplicated mitral stenosis (Wilkins score less than 8)

• Recommended for symptomatic patients with moderate to severe mitral stenosis and favorable valve morphology, no or mild mitral regurgitation, and no evidence of left atrial thrombus 
• Option for asymptomatic patients with very severe mitral stenosis and favorable valve anatomy, or with atrial fibrillation 
• Can be considered for patients with mild mitral stenosis whose symptoms cannot be explained by other causes and who also have pulmonary hypertension (greater than 25 mm Hg) with exercise 

Surgical management of mitral stenosis (commissurotomy or valve replacement) is indicated in severely symptomatic patients with severe mitral stenosis (mitral valve area of 1.5 cm² or smaller, stage D) who are not high-risk surgical candidates and who are not candidates for percutaneous mitral balloon valvotomy (or who have undergone failed percutaneous mitral balloon valvotomy) 

Prophylaxis against infective endocarditis

• Is reasonable, in patients at elevated risk, before dental procedures involving manipulation of gingival tissue or periapical region of teeth or perforation of oral mucosa; applies to patients with the following: (Related: Endocarditis)
  • Prosthetic cardiac valves
  • Prosthetic material used for cardiac valve repair (eg, annuloplasty rings and chords)
  • Previous infective endocarditis
  • Cardiac transplant with valve regurgitation due to a structurally abnormal valve
  • Unrepaired cyanotic congenital heart disease or repaired congenital heart disease, with residual shunts or valvular regurgitation at or adjacent to a prosthetic patch or prosthetic device

Drug therapy

• β-blockers 
  • For treatment of atrial fibrillation and heart failure
    • Bisoprolol
      • Atrial fibrillation
        • Bisoprolol Fumarate Oral tablet; Adults: 2.5 to 10 mg PO daily.
      • Heart failure
        • Bisoprolol Fumarate Oral tablet; Adults: Initially, 1.25 mg PO once daily for 48 hours, then 2.5 mg PO once daily for first month, then 5 mg PO once daily. Max: 10 mg PO once daily.
    • Carvedilol
      • Atrial fibrillation
        • Carvedilol Oral tablet; Adults: 3.125 to 25 mg PO twice daily.
      • Heart failure
        • Carvedilol Oral tablet; Adults: Limited data show benefit in patients NYHA Class III/IV heart failure referred for cardiac transplant. Initially, 3.125 mg PO twice daily has been evaluated, titrated up to 25 mg PO twice daily. Another trial used initial test dose of 6.25 mg PO, with weekly titration to Max tolerated dose (up to 100 mg/day). Mean dose was 58 mg (n = 48).
    • Metoprolol
      • Atrial fibrillation
        • Metoprolol Tartrate Oral tablet; Adults: 25 to 100 mg PO twice daily.
      • Heart failure
        • Metoprolol Tartrate Oral tablet; Adults: A target dose of 100 to 200 mg/day PO has been studied; a starting dose of 12.5 mg/day has been used; dose should be titrated to target as tolerated.
• Calcium channel blockers
  • For heart failure secondary to mitral stenosis, especially in those with contraindications to β-blocker therapy, and for atrial fibrillation 
    • Diltiazem
      • Diltiazem Hydrochloride Oral tablet; Adults: 30 mg PO 3 times per day, titrated to 60 to 90 mg 3 times per day, has been studied.
  • Cause less fatigue than β-blockers
• Diuretics 
  • For edema in heart failure
    • Bumetanide
      • Bumetanide Oral tablet; Infants†, Children†, and Adolescents†: 0.015 to 0.1 mg/kg/dose PO every 6 to 24 hours has been recommended (Max initial dose: 2 mg); 0.014 to 0.15 mg/kg/dose PO every 24 to 48 hours was used for 4 to 20 weeks in 8 infants with congenital heart disease and heart failure. Max dose has not been specified; Max adult dose: 10 mg/day.
      • Bumetanide Oral tablet; Adults: Initially, 0.5 to 1 mg PO daily. Multiple daily doses may be given at 4 to 5 hour intervals if the initial diuretic response is not adequate. Max: 10 mg/day.
    • Furosemide
      • Furosemide Oral solution; Infants, Children, and Adolescents: Initially, 1 to 2 mg/kg/dose PO every 6 to 12 hours. If response is inadequate after 6 to 8 hours, increase by 1 to 2 mg/kg/dose (Max: 6 mg/kg/dose). Use lowest effective dose for maintenance. For nephrotic syndrome, some experts recommend 1 to 2 mg/kg/day PO as 1 daily dose or divided twice daily.
      • Furosemide Oral tablet; Adults: Initially, 20 to 80 mg PO as a single dose; may repeat dose in 6 to 8 hours. Usual dose: 40 to 120 mg/day. Max: 600 mg/day.
      • Furosemide Oral tablet; Geriatric: See adult dose.
• Cardiac glycosides
  • Consider when β-blockers and calcium channel blockers are ineffective for rate control 
  • For heart failure
    • Digoxin
      • Loading dose
        • Digoxin Oral tablet; Children 5 to 10 years: Total dose of 20 to 45 mcg/kg PO given in 3 divided doses, with first dose equaling 50% of total loading dose. Then give 25% of total loading dose at 6 to 8 hour intervals for 2 doses; carefully assess response before each dose.
        • Digoxin Oral tablet; Adults, Adolescents, and Children older than 10 years: Total dose of 10 to 15 mcg/kg PO given in 3 divided doses, with first dose equaling 50% of total loading dose. Then give 25% of total loading dose at 6 to 8 hour intervals for 2 doses; carefully assess response before each dose.
      • Maintenance dose
        • Digoxin Oral tablet; Children 5 to 10 years: 6.4 to 12.9 mcg/kg/day PO in 2 divided doses is the recommended starting maintenance dose. Usual daily maintenance dose requirements for the treatment of congestive heart failure are based on corrected CrCl (mL/minute/1.73m2) and lean body weight (LBW). Monitor serum digoxin concentrations and adjust dosage accordingly. Doses are rounded to the nearest whole/half tablet. 
        • Digoxin Oral tablet; Adults, Adolescents, and Children older than 10 years: Initially, 3.4 to 5.1 mcg/kg/day PO given once daily. Usual daily maintenance dose requirements for the treatment of congestive heart failure are based on corrected CrCl (mL/minute per 70 kg or mL/minute/1.73m2) and lean body weight (LBW). Doses are rounded to the nearest whole/half tablet. According to the Beers Criteria, digoxin should be avoided as first-line therapy for atrial fibrillation or heart failure; if use is necessary, the drug should not be prescribed in daily doses greater than 0.125 mg.
• Anticoagulants 
  • For preventing emboli or thrombi in atrial fibrillation
    • Warfarin
      • Warfarin Sodium Oral tablet; Adults: A target INR of 2.5 (range: 2 to 3) is recommended in atrial fibrillation patients with rheumatic mitral stenosis or moderate to severe mitral stenosis. A target INR of 3 (range: 2.5 to 3.5) is recommended for atrial fibrillation patients with mechanical heart valves. Patients with mechanical heart valves should also receive aspirin 75 mg to 100 mg PO once daily
• Antibiotic prophylaxis
  • Primary treatment streptococcal infections, such as pharyngitis, to prevent rheumatic fever recurrence (Related: Pharyngitis)
    • Penicillin
      • Parenteral
        • Penicillin G Benzathine Suspension for injection; Infants and Children weighing less than 27 kg: 600,000 units IM as a single dose.
        • Penicillin G Benzathine Suspension for injection; Children and Adolescents weighing 27 kg or more: 1.2 million units IM as a single dose.
        • Penicillin G Benzathine Suspension for injection; Adults: 1.2 million units IM as a single dose.
      • Oral
        • Penicillin V Potassium Oral tablet; Infants† and Children 1 to 11 years weighing 27 kg or less†: 250 mg PO 2 to 3 times daily for 10 days is recommended by clinical guidelines.
        • Penicillin V Potassium Oral tablet; Children 1 to 11 years weighing more than 27 kg†: 500 mg PO 2 to 3 times daily for 10 days, or alternately, 250 mg PO 3 times daily for 10 days is recommended by clinical guidelines.
        • Penicillin V Potassium Oral tablet; Children and Adolescents 12 to 17 years: 500 mg PO 2 to 3 times daily or 250 mg PO 4 times daily for 10 days is recommended by clinical guidelines. FDA-approved dose is 125 to 250 mg PO every 6 to 8 hours for streptococcal infections.
        • Penicillin V Potassium Oral tablet; Adults: 500 mg PO 2 to 3 times daily or 250 mg PO 4 times daily for 10 days is recommended by clinical guidelines. FDA-approved dose is 125 to 250 mg PO every 6 to 8 hours for streptococcal infections.
    • Erythromycin (if patient has penicillin hypersensitivity)
      • Erythromycin Oral tablet; Infants, Children, and Adolescents: 30 to 50 mg/kg/day PO in 3 to 4 divided doses for 10 days (Max: 1 to 2 g/day).
      • Erythromycin Oral tablet; Adults: 250 to 500 mg (base, estolate, or stearate) PO every 6 hours or 400 to 800 mg (ethylsuccinate) PO every 6 hours for 10 days.
  • For secondary prophylaxis of recurrent streptococcal infections to prevent recurrent rheumatic fever 
    • Intramuscular injections of benzathine penicillin are preferred to oral regimens due to higher efficacy in relapse prevention 
    • Recommended for at least 10 years after the last episode of acute rheumatic fever or until age 40, whichever is the longest
      • Consider lifelong prophylaxis in high-risk patients, based on severity of valvular heart disease and exposure to group A streptococci
    • Benzathine penicillin
      • Penicillin G Benzathine Suspension for injection; Infants and Children weighing less than 27 kg: 600,000 units IM every 4 weeks, or every 3 weeks in high-risk patients.
      • Penicillin G Benzathine Suspension for injection; Children and Adolescents weighing 27 kg or more: 1.2 million units IM every 4 weeks, or every 3 weeks in high-risk patients.
      • Penicillin G Benzathine Suspension for injection; Adults: 1.2 million units IM every 4 weeks, or every 3 weeks in high-risk patients.

Nondrug and supportive care

Dietary salt restriction with heart failure 

Procedures

Percutaneous mitral balloon valvotomy

General explanation 

• Nonsurgical procedure performed via cardiac catheterization
• Involves introducing a balloon catheter into the left atrium, positioning it at the mitral valve, and widening the mitral valve by repeated inflation and deflation of the balloon

Indication

• Uncomplicated mitral stenosis: therapy of choice (Wilkins score less than 8)
• Recommended for symptomatic patients with moderate to severe mitral stenosis and favorable valve morphology, no or mild mitral regurgitation, and no evidence of left atrial thrombus 
• Option for asymptomatic patients with very severe mitral stenosis and favorable valve anatomy or when mitral valve obstruction results in atrial fibrillation 
• Can be considered for patients with mild mitral stenosis whose symptoms cannot be explained by other causes and who have pulmonary hypertension (greater than 25 mm Hg) with exercise 
• Can be considered for symptomatic patients when surgery carries high risk for adverse outcomes, even if valve morphology is suboptimal 

Contraindications 

• Moderate to severe mitral regurgitation
• Severe or bicommissural calcification
• Presence of thrombus in left atrium
• Absence of commissural fusion
• Severe concomitant aortic valve disease, or severe combined tricuspid stenosis and regurgitation requiring surgery
• Concomitant coronary artery disease requiring bypass surgery

Complications 

• Cerebral emboli
• Cardiac perforation
• Residual atrial septal defect; rarely, can be large enough to cause right-sided heart failure

Mitral valve replacement

General explanation 

• Surgical procedure with general anesthesia
• Prosthetic valve placement (mechanical or bioprosthetic valve)
• Long-term anticoagulation is required

Indication 

• Symptomatic patients with severe mitral regurgitation when balloon mitral valvotomy or surgical mitral valve repair is not possible
• Patients with combined mitral stenosis and moderate or severe mitral regurgitation
• Extensive commissural calcification
• Severe fibrosis
• Subvalvular fusion
• History of previous valvotomy

Contraindications

• Poor general surgical candidates

Complications

• Valve failure
• Valve infection
• Valve-induced thrombus

Open/closed mitral commissurotomy/valvotomy 

General explanation 

• Surgical procedures with general anesthesia
• Open mitral valvotomy (preferred)
  • Performed under direct vision via cardiopulmonary bypass
  • Thrombi removed from left atrium
  • Separation of fused chordae
  • Debridement of calcium from valve leaflets
• Closed mitral valvotomy
  • Rarely used in current US practice; replaced with balloon mitral valvotomy
  • Performed without cardiopulmonary bypass but with a transventricular dilator
  • Most effective when mitral regurgitation, atrial thrombosis, and valvular calcification are not serious and chordal fusion and shortening are not severe

Indication

• Patients with severe mitral stenosis and significant symptoms when mitral balloon valvotomy is not available or is contraindicated because of left atrial thrombus or moderate to severe mitral regurgitation, or when the valve is calcified and surgical risk is acceptable 

Contraindications

• Patients with multivalvular lesion requiring valve replacement

Complications 

• Valve failure
• Mitral regurgitation
• Thromboembolism

Comorbidities

• Tachyarrhythmia (eg, atrial fibrillation) 
  • Decreases diastolic time for ventricular filling, reducing cardiac output
  • Can result in symptomatic heart failure

Special populations

• Pregnant women
  • Increase in metabolic demands in the second and third trimesters of pregnancy can cause sudden and life-threatening complications in an otherwise asymptomatic patient with mitral stenosis 
  • Mitral stenosis is often poorly tolerated when valve area is less than 1.5 cm², even in previously asymptomatic patients 
  • Symptomatic mitral stenosis should be treated with bed rest and β-blockers, possibly associated with diuretics 
  • With persistent dyspnea or pulmonary arterial hypertension despite medical therapy, consider percutaneous mitral balloon valvotomy after the 20th week 
  • Consider anticoagulant therapy 
• Elderly patients
  • When surgery presents high risk or is contraindicated but life expectancy is still acceptable, percutaneous mitral balloon valvotomy is a useful option, even if only as a palliative measure 

Monitoring

• Perform transthoracic echocardiography to reevaluate asymptomatic patients with mitral stenosis and stable clinical findings, to assess pulmonary artery pressure and valve gradient 
  • Very severe mitral stenosis with mitral valve area less than 1 cm²: every year
  • Severe mitral stenosis with mitral valve area of 1.5 cm² or smaller: every 1 to 2 years
  • Progressive mitral stenosis with mitral valve area more than 1.5 cm²: every 3 to 5 years

Complications

• Atrial fibrillation
  • 17% of patients aged 21 to 30 years
  • 45% of those aged 31 to 40 years
  • 60% of those aged 41 to 50 years
  • 80% of those older than 51 years
• Systemic embolism from left atrial thrombus 
  • Stroke; approximately 50% of all clinically apparent emboli are found in the cerebral vessels 
• Bacterial endocarditis (Related: Endocarditis)
• Left-sided heart failure (Related: Heart failure)
• Right-sided heart failure
• Pulmonary hypertension

Prognosis

• Severity of stenosis progresses in almost all patients
• Drugs can only provide symptomatic relief and delay the need for surgery
• Surgical management is not curative but may prolong survival
• Restenosis can occur

Prevention

• Treat streptococcal infections promptly 
  • Pursue early diagnosis and treatment of rheumatic fever
  • Treating acute streptococcal pharyngitis with appropriate antibiotics helps to prevent rheumatic fever

Sources

Soliman OI et al: New scores for the assessment of mitral stenosis using real-time three-dimensional echocardiography. Curr Cardiovasc Imaging Rep. 4(5):370-7, 2011 Reference