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]

Synonyms and keywords: Mitral valve stenosis; narrowing of mitral valve

Overview

Mitral stenosis refers to abnormal narrowing of mitral orifice, which leads to obstruction of blood flow from left atrium to left ventricle. 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

Diagnosis

Shown below is an algorithm summarizing the approach to the initial evluation of mitral stenosis according to 2014 AHA/ACC guidelines for management of valvular heart disease..
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: ❑ History of rheumatic fever ❑ Exercise intolerance ❑ Dyspnea on exertion ❑ Palpitations ❑ Orthopnoea ❑ Paroxysmal nocturnal dyspnea ❑ Hoarseness ❑ Cough ❑ Hemoptysis ❑ Thromboembolism ❑ Respiratory infections ❑ Fatigue ❑ Right heart failure signs: ❑ Peripheral edema ❑ Ascites ❑ Hepatomegaly

Examine the patient: Appearance of the patient ❑ Plethoric cheeks with bluish patches Vital signs ❑ Pulse ❑ Rate ❑ Tachycardia ❑ Rhythm ❑ Irregularly irregular (with onset of AF) ❑ Strength ❑ Reduced pulse pressure ❑ Reduced in volume Neck: ❑ Jugular venous distension ❑ Prominent a wave in right heart failure ❑ Absent a wave in AF ❑ Prominent v wave in TR Chest examination: Auscultation ❑ Left parasternal heave ❑ Loud S1 ❑ Loud P2 (indicates pulmonary hypertension) ❑ Opening snap ❑ Murmur ❑ Mid diastolic murmur (low pitched, rumbling) ❑ Holosystolic murmur indicates TR ❑ Graham-Steell murmur indicates pulmonary regurgitation {{#ev:youtube|HW2pk1icYdM|250}} Video adapted from Youtube.com ❑ Rales

Order tests: ❑ Perform 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 ❑ RV1 = 7 mm or more ❑ RV1 + SV5 or SV6 = 10 mm or more ❑ R/S ratio in V1 = 1.0 or more ❑ S/R ratio in V6 = 1.0 or more ❑ Incomplete RBBB pattern ❑ ST T strain pattern in leads 2,3,aVF ❑ P pulmonale or right atrial enlargement or P congenitale ❑ R wave progression reversal ❑ Inverted T wave in the anterior precordial leads ❑ Right axis deviation ❑ QRS complex is positive in leads III and aVF ❑ QRS complex is negative in leads I and aVL ❑ Atrial fibrillation ❑ Absence of P waves ❑ Irregularly irregular heart rate Picture adapted from Wikidoc.org ❑ Perform 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 ❑ Perform 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

Consider alternative diagnosis: ❑ Myxoma ❑ Obstruct the mitral orifice ❑ Exclude with echocardiography ❑ Atrial fibrillation ❑ Order echocardiography to exclude mitral stenosis

Treatment

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.

Medical therapy ❑ Consider heart rate control in MS patients with: ❑ Normal sinus rhythm and symptoms present on exercise ❑ AF and fast ventricular response ❑ Consider anticoagulation therapy in MS patients with: ❑ AF ❑ Prior embolic event ❑ Left atrial thrombus

Shown below is an algorithm summarizing the approach to 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

❑ 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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