Mitral stenosis resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Definition

Mitral stenosis refers to abnormal narrowing of mitral orifice which leads to obstruction of blood flow from left atrium to left ventricle and development of a pressure gradient between the two chambers.

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

Initial Evaluation

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..

Characterize the symptoms: ❑ 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: Pulse ❑ Tachycardia ❑ Reduced pulse pressure ❑ Irregularly irregular (with onset of AF) ❑ Reduced in volume Head: ❑ Mitral facies ❑ Plethoric cheeks with bluish patches Neck: ❑ Jugular venous distension ❑ Prominent a wave in right heart failure ❑ Absent a wave in AF ❑ Prominent v wave in TR Chest: ❑ 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 ❑ Rales

❑ Perform EKG ❑ Perform chest X-ray ❑ Perform transthoracic echocardiography

Assess the following on TTE: ❑ Valve area ❑ Disease of other valves ❑ Mean pressure gradient ❑ Pulmonary artery pressure ❑ Suitability of valve morphology for PMBC

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

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

Management

Shown below is an algorithm summarizing the approach to management of mitral stenosis according to 2014 AHA/ACC guidelines for management of valvular heart disease.

❑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 valve morphology is favorable for PMBC

❑ Monitor patient periodically

Yes

No

❑ Assess if PCWP > 25 mm Hg on exercise

Yes

No

No

Yes

❑ Proceed with PMBC

❑ Assess if patient is severely symptomatic (NYHA III/IV) ❑ Assess if the risk of surgery is high

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

❑ Proceed with PMBC

❑ Monitor patient periodically

❑ Assess for the presence of new onset AF

Yes

No

AF present

No AF

❑ Proceed with PMBC

❑ Proceed with mitral valve surgery

❑ Proceed with PMBC

❑ Monitor patient periodically

MVA: Mitral valve area; PMBC: Percutaneous mitral ballon commissurotomy; PCWP: Pulmonary capillary wedge pressure; ms: milliseconds; NYHA: New York Heart Association; AF: Atrial fibrillation

Do's

• Perform trans-esophageal 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.

References

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