Mitral stenosis resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Twinkle Singh, M.B.B.S. [2]; Mohamed Moubarak, M.D. [3]

Mitral Stenosis Resident Survival Guide Microchapters
Overview
Causes
FIRE
Diagnosis
Treatment Medical Therapy Summary for Mitral Stenosis Intervention
Rheumatic Fever Prophylaxis
Do's

Overview

Mitral stenosis refers to abnormal narrowing of mitral orifice, which leads to obstruction of blood flow from left atrium to left ventricle most commonly as a complication of rheumatic fever. The most common presentations of mitral stenosis are dyspnea, orthopnea, paroxysmal nocturnal dyspnea, and peripheral edema. Mitral stenosis has a characteristic low-pitched, rumbling diastolic murmur, heard best at the apex during physical examination. The definitive therapy for mitral stenosis include percutaneous balloon valvotomy, surgical mitral valve repair, or mitral valve replacement.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated.

• Infective endocarditis

Common Causes

• Congenital
• Infective endocarditis
• Mitral annular calcification
• Rheumatic fever

Click here for the complete list of causes

FIRE: Focused Initial Rapid Evaluation

A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients in need of immediate intervention.

Boxes in the red color signify that an urgent management is needed.

Identify cardinal findings that increase the pretest probability of mitral stenosis ❑ Mid diastolic murmur ❑ Low-pitched diastolic rumble ❑ Associated with an opening snap ❑ Best heard at the cardiac apex ❑ Radiating to the axilla ❑ Increases with lying down, raising the legs and with exercise ❑ Decreases with valsalva maneuver and amyl nitrate ❑ Reduced pulse pressure

Does the patient have any of the following findings of decompensated mitral stenosis that require urgent management? ❑ Tachycardia ❑ Hypotension ❑ Severe dyspnea ❑ Loss of consciousness ❑ Chest pain

Yes

No

What is the complication of mitral stenosis that is causing decompensation?

Continue with the complete diagnostic approach below

Stroke ❑ Suspect in case of: ❑ Sudden weakness or paralysis - face, arm or leg ❑ Speech or visual difficulties ❑ Altered level of consciousness ❑ Sudden severe headache

Atrial fibrillation ❑ Suspect in case of palpitations ❑ Order an ECG immediately looking for ❑ Irregularly irregular rhythm, and ❑ Absent P waves

Pulmonary embolism ❑ Suspect in case of: ❑ Acute onset of exertional dyspnea or dyspnea at rest ❑ Pleuritic or substernal chest pain ❑ Hemoptysis

Pulmonary hypertension ± right sided heart failure ❑ Suspect in case of severe dyspnea ❑ Increased jugular venous pressure immediately ❑ Hepatomegaly ± pulsatile liver

Click here for stroke resident survival guide

Click here for atrial fibrillation resident survival guide

Click here for pulmonary embolism resident survival guide

Click here for Pulmonary hypertension resident survival guide, or Click here for Acute heart failure resident survival guide

❑ Treat the complications of mitral stenosis that lead to decompensation ❑ Order a TTE to evaluate the severity of the mitral stenosis

When to consider intervention in mitral stenosis ? ❑ Continue with the treatment algorithm below

Complete Diagnostic Approach

A complete diagnostic approach should be carried out after a focused initial rapid evaluation is conducted and following initiation of any urgent intervention..
Abbreviations: AF: Atrial fibrillation; PMBC: Percutaneous mitral ballon commissurotomy; TR: Tricuspid regurgitation; S1: First heart sound; P2: Pulmonary component of second heart sound; EKG: Electrocardiogram; TTE: Transthoracic echocardiography; MS: Mitral stenosis

Characterize the symptoms: ❑ Exercise intolerance ❑ Dyspnea on exertion ❑ Palpitations ❑ Orthopnoea ❑ Paroxysmal nocturnal dyspnea ❑ Hoarseness ❑ Cough ❑ Hemoptysis ❑ Thromboembolism ❑ Stroke ❑ Pulmonary embolism ❑ Respiratory infections ❑ Fatigue ❑ Right heart failure

Inquire about past medical history: ❑ Rheumatic fever ❑ Respiratory infection ❑ Congenital MS

Examine the patient: Appearance of the patient ❑ Plethoric cheeks with bluish patches Vital signs ❑ Pulse ❑ Rate ❑ Tachycardia ❑ Rhythm ❑ Irregularly irregular (suggestive of AF) ❑ Strength ❑ Reduced pulse pressure ❑ Reduced in volume Neck: ❑ Jugular venous distension ❑ Prominent a wave (suggestive of right heart failure) ❑ Absent a wave (suggestive of AF) ❑ Prominent v wave (suggestive of TR) Extremities: ❑ Peripheral edema (suggestive of right sided heart failure) Abdominal examination: ❑ Ascites (suggestive of right sided heart failure) ❑ Hepatomegaly (suggestive of right sided heart failure) Cardiovascular examination: Auscultation ❑ Left parasternal heave ❑ Loud S1 ❑ Loud P2 (indicates pulmonary hypertension) ❑ Opening snap ❑ Murmur ❑ Most prominent at the apex and best heard using the bell of the stethoscope ❑ Mid diastolic murmur (low pitched, rumbling) ❑ Holosystolic murmur (suggestive of TR) ❑ Graham-Steell murmur (suggestive of pulmonary regurgitation) {{#ev:youtube|HW2pk1icYdM|250}} Video adapted from Youtube.com ❑ Rales

Order tests: ❑ Transthoracic echocardiography ❑ Assess valve area ❑ Assess disease of other valves ❑ Assess mean pressure gradient ❑ Assess pulmonary artery pressure ❑ Assess suitability of valve morphology for PMBC ❑ EKG ❑ Left atrial enlargement ❑ Broad, bifid P wave in lead II (P mitrale) Picture adapted from en.ecgpedia.org ❑ Biphasic P wave with terminal negative portion Picture adapted from en.ecgpedia.org ❑ Right ventricular hypertrophy ❑ Right axis deviation of +90 degrees or more ❑ Incomplete RBBB pattern ❑ ST T strain pattern in leads 2,3,aVF ❑ P pulmonale or right atrial enlargement or P congenitale ❑ Inverted T wave in the anterior precordial leads Click here for the rest of the EKG findings in right ventricular hypertrophy ❑ Right axis deviation ❑ QRS complex is positive in leads III and aVF ❑ QRS complex is negative in leads I and aVL Shown below an ECG depicting right axis deviation ❑ Atrial fibrillation ❑ Absence of P waves ❑ Irregularly irregular heart rate Shown below an ECG depicting atrial fibrillation Picture adapted from Wikidoc.org ❑ Chest X-ray ❑ Double right heart border (suggestive of left atrial hypertrophy) ❑ Prominent pulmonary artery ❑ Kerley lines (suggestive of interstitial pulmonary edema) Picture adapted from Radiopedia.org

Classify mitral stenosis based on the following findings on TTE: ❑ Valve anatomy ❑ Valve hemodynamics gradient ❑ Hemodynamic consequences

Stage A ❑ No symptoms ❑ Patient at risk of developing mitral stenosis ❑ Mild valve doming during diastole ❑ Normal transmitral flow velocity

Stage B ❑ No symptoms ❑ Progressive mitral stenosis ❑ Valve area > 1.5 cm² ❑ Rheumatic valve changes with commissural fusion and diastolic doming of the mitral valve leaflets ❑ Increased transmitral flow velocities ❑ Diastolic pressure half-time < 150 ms ❑ Mild to moderate left atrial enlargement ❑ Normal pulmonary pressure at rest

Stage C ❑ Asymptomatic severe mitral stenosis ❑ Valve area ≤ 1.5 cm² (≤ 1 cm² in severe mitral stenosis) ❑ Rheumatic valve changes with commissural fusion and diastolic doming of the mitral valve leaflets ❑ Diastolic pressure half-time ≥ 150 ms (≥ 220 ms with very severe mitral stenosis) ❑ Elevated pulmonary artery systolic pressure > 30 mmHg ❑ Severe left atrial enlargement

Stage D ❑ Symptomatic severe mitral stenosis ❑ Valve area ≤ 1.5 cm² (≤ 1 cm² in severe mitral stenosis) ❑ Rheumatic valve changes with commissural fusion and diastolic doming of the mitral valve leaflets ❑ Diastolic pressure half-time ≥ 150 ms (≥ 220 ms with very severe mitral stenosis) ❑ Elevated pulmonary artery systolic pressure > 30 mmHg ❑ Severe left atrial enlargement

Treatment

Shown below is an algorithm summarizing the management of rheumatic mitral stenosis according to 2014 AHA/ACC guidelines for management of valvular heart disease.
MVA: Mitral valve area; PMBC: Percutaneous mitral ballon commissurotomy; PCWP: Pulmonary capillary wedge pressure; ms: milliseconds; NYHA: New York Heart Association; AF: Atrial fibrillation

Medical Therapy

The filling of the left ventricle depends upon the diastole time which is limited by mitral stenosis. Therefore, slowing the heart rate is crucial in the initial management of mitral stenosis in order to improve the diastole time and consequently improve the filling of the left ventricle.

Classify mitral stenosis based on TTE: ❑ Valve anatomy ❑ Valve hemodynamics gradient ❑ Hemodynamic consequences

Stage A

Stage B

Stage C

Stage D

❑ Yearly follow up is recommended with history and physical examination in asymptomatic patients with mild MS ❑ For mild MS repeat echocardiography every 3-5 years ❑ For moderate MS repeat echocardiography every 1-2 years ❑ The onset of symptoms require medical therapy and re-evaluation of the stage as the patient may also need intervention in moderate and severe disease

Continue with the summary for mitral stenosis intervention below

The presence of symptoms is an indication for intervention Indications for pharmacotherapy: ❑ Alleviate symptoms before surgery ❑ Control symptoms precipitated by intercurrent illness or during pregnancy ❑ Persistent symptoms after intervention Medications: ❑ Diuretics: used to relieve symptoms of pulmonary vascular congestion (shortness of breath, orthopnea and paroxysmal nocturnal dyspnea) and in case of right sided heart failure ❑ Beta blockers: useful to control exertional symptoms as it decreases heart rate and cardiac output during exercise, thus decreasing the rise in transmitral gradient ❑ Digoxin: used in case of right or left ventricular systolic dysfunction and also during atrial fibrillation (not the first line) ❑ Statin therapy: slower progression of rheumatic mitral stenosis Antithrombotic recommendations: Consider anticoagulation therapy in MS patients with: ❑ AF ❑ Prior embolic event ❑ Left atrial thrombus Long term oral anticoagulation (2.0-3.0 INR) Prevention of endocarditits: No longer require antimicrobial prophylaxis

Continue with the summary for mitral stenosis intervention below

Summary for Mitral Stenosis Intervention

❑ Assess the presence of symptoms

Symptomatic

Asymptomatic

❑ Assess the severity of mitral stenosis

❑ Assess the severity of mitral stenosis

Very severe ❑ MVA ≤ 1 cm2 ❑ Pressure half time ≥ 220 ms ❑ Stage D

Severe ❑ MVA ≤ 1.5 cm2 ❑ Pressure half time ≥ 150 ms ❑ Stage D

Progressive ❑ MVA > 1.5 cm2 ❑ Pressure half time < 150 ms

Very severe ❑ MVA ≤ 1 cm2 ❑ Pressure half time ≥ 220 ms ❑ Stage C

Severe ❑ MVA ≤ 1.5 cm2 ❑ Pressure half time ≥ 150 ms ❑ Stage C

Progressive ❑ MVA > 1.5 cm2 Pressure half time < 150 ms

❑ Assess if valve morphology is favorable for PMBC

❑ Perform exercise testing

❑ Assess if valve morphology is favorable for PMBC

❑ Assess if the new onset AF is present

❑ Monitor patient periodically

Yes

No

❑ Assess PCWP on exercise

Yes

No

No

Yes

❑ Proceed with PMBC

If patient is severely symptomatic (NYHA III/IV): ❑ Assess the surgical risk of patient

If PCWP > 25 mm Hg: ❑ Proceed with PMBC If PCWP< 25 mm Hg : ❑ Monitor patient periodically

❑ Proceed with PMBC

❑ Monitor patient periodically

❑ Assess if the valve morphology is favorable for PMBC

Yes

No

Yes

No

❑ Proceed with PMBC

❑ Proceed with mitral valve surgery

❑ Proceed with PMBC

❑ Monitor patient periodically

Rheumatic Fever Prophylaxis

Shown below is the table depicting the secondary prophylaxis of rheumatic fever according to the 2014 AHA/ACC guideline for the management of valvular heart disease.

Secondary prevention of rheumatic fever Penicillin G benzathine ▸ 1.2 million units IM every day for 4 weeks Penicillin V potassium ▸ 200 mg orally twice a day Sulfadiazine ▸ 1 g orally once a day Macrolide antibiotics (in patients allergic to penicillin) ▸ Varies

Indications	Duration of prophylaxis
▸ Rheumatic fever with carditis and persistent valvular heart disease	▸ 10 years or until the patient is 40 years (whichever is longer)
▸ Rheumatic fever with carditis but no valvular heart disease	▸ 10 years or until the patient is 21 years (whichever is longer)
▸ Rheumatic fever without carditis	▸ 5 years or until the patient is 21 years (whichever is longer)

Do's

• Perform transesophageal echocardiography (TEE) in patients considered for PMBC to rule out left atrial thrombus and to determine mitral regurgitation severity.
• Perform exercise testing or invasive hemodynamic testing, when clinical signs and symptoms don't co-relate with echocardiographic findings.
• Perform mitral valve surgery in stage C and stage D mitral stenosis, if patient is undergoing cardiac surgery for some other indication.
• Perform mitral valve surgery in moderate mitral stenosis (mitral valve area: 1.6 - 2 cm²) if the patient is undergoing cardiac surgery for other indications.
• Perform mitral valve surgery with excision of left atrial appendage in stage C and stage D mitral stenosis patients who have had recurrent embolic events despite being on anticoagulation therapy.
• Perform TTE every 3-5 years in asymptomatic stage B MS patients and every 1-2 years in asymptomatic stage C MS patients who have mitral valve area 1-1.5 cm² .
• Perform TTE once every year in asymptomatic stage C MS patients who have mitral valve area < 1 cm².
• In cases of senile calcific mitral stenosis, intervention is done only when symptoms are severe and cannot be controlled with heart rate control and diuretics.

References

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