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]; Amr Marawan, M.D. [4]; Rim Halaby, M.D. [5]

Mitral Stenosis Resident Survival Guide Microchapters
Overview
Causes
Stages
FIRE
Diagnosis
Treatment Medical Therapy Intervention
Secondary Prevention of Rheumatic Fever
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

Stages

Shown below is a table depicting the 4 stages of mitral stenosis, adapted from 2014 AHA/ACC guidelines for management of valvular heart diseases.

Abbreviations: MS: mitral stenosis; MVA: mitral valve area; PASP: pulmonary artery systolic pressure

Stage	Definition	Valve anatomy	Valve hemodynamics	Hemodynamic consequences	Symptoms
A	At risk of MS	❑ Mild diastolic doming of mitral valve leaflets	❑ Normal transmitral velocity	Absent	Absent
B	Progressive MS	❑ Rheumatic valve changes characterized by commissural fusion and diastolic doming of mitral valve ❑ MVA > 1.5 cm2 (planimetered)	❑ Increased transmitral flow velocities ❑ MVA > 1.5 cm2 ❑ Pressure half time during diastole < 150 ms	❑ Mild to moderate left atrial enlargement ❑ Normal pulmonary pressure at rest	None
C	Asymptomatic severe MS	❑ Rheumatic valve changes characterized by commissural fusion and diastolic doming of mitral valve ❑ MVA ≤ 1.5 cm2 ❑ MVA ≤ 1 cm2 in very severe MS	❑ MVA ≤ 1.5 cm2 (planimetered) ❑ MVA ≤ 1 cm2 (planimetered) in very severe MS ❑ Diastolic pressure half time ≥ 150 ms ❑ Diastolic pressure half time ≥ 220 ms with very severe MS	❑ Severe left atrial enlargement ❑ PASP > 30 mm Hg	Absent
D	Symptomatic severe MS	❑ Rheumatic valve changes characterized by commissural fusion and diastolic doming of mitral valve ❑ MVA ≤ 1.5 cm2 (planimetered)	❑ MVA ≤ 1.5 cm2 ❑ MVA ≤ 1 cm2 in very severe MS ❑ Diastolic pressure half time ≥ 150 ms ❑ Diastolic pressure half time ≥ 220 ms with very severe MS	❑ Severe left atrial enlargement ❑ PASP > 30 mm Hg	❑ Dyspnea on exertion ❑ Decreased exercise tolerance

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 ❑ Sudden weakness or paralysis

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 ❑ Exercise testing with Doppler or invasive hemodynamic assessment in case of discrepancy between resting Doppler echocardiographic findings and clinical symptoms or signs ❑ Assess the response of the mean mitral gradient ❑ Assess the pulmonary artery pressure ❑ 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

Stage B

Stage C

Stage D

Treatment

Medical Therapy

Treatment of Acute Decompensation ❑ Digoxin In the following cases: ❑ Symptomatic right ventricular or left ventricular dysfunction (digitalis increases myocardial contractility) ❑ Atrial fibrillation (digitalis slows the ventricular response which prolongs the diastolic filling time) ❑ Diuretics (In the following cases fluid overload) ❑ Low sodium diet ❑ Activity restriction Systemic Embolization Prevention In the following cases: ❑ Paroxysmal, persistent, or permanent atrial fibrillation (Class I, Level of Evidence B) ❑ Prior embolization event (Class I, Level of Evidence B) ❑ Left atrial thrombus (Class I, Level of Evidence B) Rate Control In the following cases: ❑ Atrial fibrillation associated with fast ventricular response (Class IIa, Level of Evidence C) ❑ Normal sinus rhythm plus symptoms associated with exercise (Class IIb, Level of Evidence B)

Intervention

Shown below is an algorithm depicting the indications for mitral stenosis intervention according to the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease.

Abbreviations: AF: atrial fibrillation; MR: mitral regurgitation; MS: mitral stenosis; MVA: mitral valve area ; PCWP: pulmonary capillary wedge pressure; PMBC: percutaneous mitral balloon commissurotomy; T_1/2: pressure half-time

Determine the severity of rheumatic mitral stenosis (MS)

Very severe MS ❑ MVA ≤1 cm2 ❑ T1/2 ≥220 ms

Severe MS ❑ MVA ≤1.5 cm2 ❑ T1/2 ≥150 ms

Progressive MS MVA >1.5 cm2 T1/2 <150 ms

Is the patient symptomatic?

Is the patient symptomatic?

Is the patient symptomatic?

No ( Stage C)

Yes (Stage D)

No (Stage C)

Yes With no other cause for the symptoms

Does the patient have: ❑ Favorable valve morphology AND ❑ No left atrial clot AND ❑ No or mild MR

Does the patient have: ❑ Favorable valve morphology AND ❑ No left atrial clot AND ❑ No or mild MR

Is there a new onset of AF?

Order an exercise treadmill test

No

Yes

Yes

No

Yes

No

Is PCWP> 25 mm Hg?

Does the patient have: ❑ NYHA class III-IV symptoms AND ❑ High surgical risk

Does the patient have: ❑ Favorable valve morphology AND ❑ No left atrial clot AND ❑ No or mild MR

No

Yes

Yes

No

Yes

No

Periodic monitoring

PMBC (Class IIa)

PMBC (Class I)

Mitral valve surgery (Class I)

PMBC (Class IIb)

Periodic monitoring

PMBC (Class IIb)

Periodic monitoring

Secondary Prevention of Rheumatic Fever

Indications

Shown below is the table depicting the indication for secondary prophylaxis of rheumatic fever.

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) (Class I, Level of Evidence C)
▸ Rheumatic fever with carditis but no valvular heart disease	▸ 10 years or until the patient is 21 years (whichever is longer) (Class I, Level of Evidence C)
▸ Rheumatic fever without carditis	▸ 5 years or until the patient is 21 years (whichever is longer) (Class I, Level of Evidence C)

Antibiotic Regimens

Shown below is the table depicting the antibiotic regimens for secondary prophylaxis of rheumatic fever.

Antibiotics	Dosage
Penicillin G benzathine (Class I, Level of Evidence A)	▸ Weight >27 Kg (60 lb): 1.2 million units IM every day for 4 weeks ▸ Weight ≤27 Kg (60 lb): 600,000 units IM every day for 4 weeks
Penicillin V (Class I, Level of Evidence B)	▸ 200 mg orally twice a day
Sulfadiazine (Class I, Level of Evidence B)	▸ Weight >27 Kg (60 lb): 1 g orally once a day ▸ Weight ≤27 Kg (60 lb): o.5 g orally once a day
Macrolide or azalide antibiotics (in patients allergic to penicillin) (Class I, Level of Evidence C)	▸ Varies

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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