Valvular Heart Disease: The Mitral Valve

Valvular Heart Disease:The Mitral Valve

Case

• A 45 year old man presents to establish care. He was told many years ago that he needed antibiotics prior to dental work because there was a problem with a heart valve. He has occasional palpitations. On exam he has brisk carotid upstrokes and a holosystolic murmur is heard best at the apex along with an S3 and a diastolic rumble.

Case

• What is the next best step?– Do nothing, this murmur is benign– Do an exercise stress test because the patient may

have CAD and ischemic heart disease– Do nothing, exam findings suggest mild disease– Order an echocardiogram – Refer the patient to a cardiologist for further

evaluation

Case

• An echocardiogram shows moderately dilated left atrium, a normal appearing left ventricle with am EF of 55%, a prolapsing posterior mitral leaflet and severe MR. Now you should:– Tell the patient to continue antibiotic prophylaxis

prior to the dental work– Have the patient follow up with a annual echo– Refer the patient for valve surgery– Refer the patient for a defibrilator to prevent

sudden death from MVP

What Makes A Heart Murmur?

• High blood flow through a normal or abnormal orifice

• Forward flow through a narrowed or irregular orifice

• Backward flow through an incompetent valve

These Murmurs Are Benign

• Mid systolic murmur at the left sternal border with grade 2 or less with a normal S1 and S2 and no other abnormal findings in an otherwise asymptomatic patient

• Associated with normal or increased blood flow across normal valves

These Murmurs Need Further Evaluation

• Diastolic Murmurs• Continuous Murmurs • Systolic

– Loud– Early systolic– Late systolic– Holosystolic

Strategy For The Evaluation Of Cardiac Murmurs

Bonow. JACC. 2006.

When To Order An Echo

• Class I– Diastolic, continuous, holosystolic, late systolic,

clicks, radiation to neck or back– Symptoms of underlying cardio-pulmonary disease– Grade 3 or louder mid systolic murmurs

• Class III– Mid systolic mumur grade II or less thought to be

innocent

Mitral Valve Disease: From Many Structures

• Mitral leaflets• Chordae• Papillary muscles• Mitral anulus

Otto. NEJM, 2001.

Etiology of Mitral Regurgitation

• Organic (Primary pathology of the leaflets)– Degenerative– Rheumatic– Endocarditis– Congenital

• Functional (Secondary to myocardial process)– Ischemic – Dilated cardiomyopathy– Hypertrophic cardiomyopathy

Enriquez-Serano. Contemporary Cardiology, 2009.

Mitral Regurgitation: Epidemiology

• Prevalence: >5,000,000• Incidence: >650,000 new cases/year in the US• Most common discharge diagnosis• Most common cause of readmission < 60 days• Cost: > 34.8 billion annualy

Rosamond. Circulation, 2008.Braunwald. 2007.

Pathophysiology• Volume overload ->

– LV dilation– LA dilation

• Acute: Rapidly increasing LA/PV pressures-> pulmonary edema

• Chronic: Slow enlargement of the LA with low pressures

• Left ventricular dilation and increased EF followed by LV deterioration

Foster. NEJM, 2002.

Hemodynamic Stages of Mitral Regurgitation

Libby. Braunwald’s Heart Disease. 8th Ed.

Natural History of Severe MR


Degenerative Mitral Valve Disease: Mitral Valve Prolapse

• Most common organic mitral valve disease

• Incidence about 2-3% • Usually results in mitral

valve prolapse • Variable histology

– Increased extracellular matrix

– Thickened and redundant– Chordal elongation

Sanders. Forensic Science International, 2007.

Complications• Chordal rupture and flail leaflet

– 12% of patients– Most common in older men

• Heart failure• Sudden death• AF• Endocarditis

– Most common compliation, but rare (100cases/100,000 patient years)

– Higher risk with flail leaflet

Mitral Regurgitation: Mitral Valve Prolapse

Foster. NEJM. 2010.

Echocardiogram: Flail Mitral Leaflet

Foster. NEJM. 2010.

Endocarditis

• Destruction of tissue by infection

• About 5% of severe MR

Mitral Regurgitation From Connective Tissue Disease

Functional Mitral Regurgitation

• Affects 15-20% with HF, 12% 30 days post MI

• Leaflets are normal• Coaptation is

incomplete• Can also be associated

with papillary muscle rupture

Marasco. Heart, Lung and Circulation, 2008.

Prosthetic Valve Failure

Alexander. Circulation, 1995.

Prosthetic Valve Failure

Novarro. JASE, 2000.

St Jude Mitral Valve

Butany. J Clin Path, 2005

Physical Exam Findings

• Brisk carotid upstrokes, laterally displaced forceful apical impulse

• Murmur: characteristics don’t reliably predict severity– Similar to AS, TR and VSD– Constant intensitiy, holosystolic, loud blowing,

apical with axillary radiation– Dimimished S1, split S2, possible S3 and loud P2– Highly variable depending on structures involved

Dynamic Auscultation

Intervention

Hypertrophic Obstructive Cardiomyopathy Aortic Stenosis

Mitral Regurgitation

Mitral Valve Prolapse

Valsalva ↑ ↓ ↓ ↑ or ↓Standing ↑ ↑ or

unchanged↓ ↑

Handgrip or squatting

↓ ↓ or unchanged

↑ ↓

Supine position with legs elevated

↓ ↑ or unchanged

Unchanged ↓

Exercise ↑ ↑ or unchanged

↓ ↑

Amyl nitrite ↑↑ ↑ ↓ ↑Isoproterenol ↑↑ ↑ ↓ ↑


XR Findings

• Prominent left atrial enlargement

• Left ventricular enlargement

• Pulmonary edema in acute MR


Atrial Fibrillation Affects 50% of Patients Within 10 Years


Acute Mitral Regurgitation Elevated PAP and Large PCWP V Waves


Variable Presentations of Mitral Regurgitation


Mitral Regurgitation Severity By Echo• Structural

– LA size– LV size– Mitral leaflets and apparatus

• Doppler– Jet area and characterisitics– Mitral inflow– Pulmonary vein flow

• Quantitative– Regurgitant orifice area– Vena contracta– Right ventricle

Zoghbi. JASE, 2003.

Medical Management

• Diuretics to maintain euvolemia• Digoxin and beta blocker for rate control• Medical therapy directed at underlying

ischemia• No benefits to vasodilators• Afterload reduction and inotropic support in

acute mitral regurgitation

Survival: Medical Management of Organic MV Regurgitation


MildModerate

Severe

Mitral Valve Prolapse Repair

Foster. NEJM. 2010.

Prosthetic Mitral Valve

Bloomfield. Heart, 2002.

Survival After Surgical Correction By EF


Repair vs Replacement

• Repair can be accomplished in 80-90%• Advantages

– Possible lower mortality rates– Possible reduced need for anticoagulation– Lower risk of endocarditis

Foster. NEJM. 2010.

Possible Survival Benefit With Mitral Valve Repair

Shuhaiber. EJCTS, 2007.

Chronic Severe MR

Bonow. JACC, 2006.

Percutaneous Therapies• 1/3 of European patients with severe

valve disease are denied surgery• 1/2 of patients with severe

symptomatic MR

Piazza. JACC, 2009.Feldman. JACC, 2009

Mitral Stenosis• Most commonly from

rheumatic fever: 99%• 2-20 years until symptoms

of MS• Likely worsened by

recurrent RF• Also

– Congenital– CTD, RA– Mucopolysaccharidoses

• Mimicks– Tumors– Infection– membranes

http://www.yale.edu/imaging/echo_atlas/entities/mitral_stenosis.html

Hemodynamics

• Normal valve orifice 4-6 cm2

• Small valve area requires higher pressure gradient

• Symptoms precipitated by fast heart rate– Higher LA-LV pressure gradient– Lower cardiac output


Hemodynamics: Why Symptoms Develop

• Increased left atrial pressure• Increase in left ventricular diastolic pressure• Pulmonary hypertension• Everything is worse with exercise• Chronic atrial changes lead to arrhythmia

Clinical Findings• Presentation

– Dyspnea, hemoptysis, chest pain, arrhythmia, embolic events, hoarseness

• Exam findings– Accentuated S1– Opening snap- at the apex with the diaphragm– A2-OS snap good indicator of severity– Findings of pulmonary hypertension– Low pitched rumbling murmur at the apex– Maneuvers that increase mitral flow increase murmur and

decrease A2-OS time

Echo Determinants Of Mitral Stenosis Severity

Baumgartner. JASE, 2009.

Echo Determinants Of Mitral Stenosis Severity

Mild Moderate Severe

Valve Area (cm2) >1.5 1.0-1.5 <1.0

Mean Gradient (mmHg)

<5 5-10 >10

PAP (mmHg) <30 30-50 >50

Mitral Valvuloplasty Score

Baumgartner. JASE, 2009.

Natural History of 159 Patients With Un-Operated Mitral Valve Disease

Mitral stenosis

Mitral regurgitation

Expected survival


Management Approach to Mitral Stenosis

Nobuyoshi. Circulation, 2009.

Percutaneous Valvuloplasty

Nobuyoshi. Circulation, 2009.

http://circ.ahajournals.org/content/vol119/issue8/images/large/1FF3.jpeg

Long Term Outcome For Percutaneous Valvuloplasty


Endocarditis Prophylaxis

• Prosthetic valve material• Prior endocarditis• Congenital heart disease

– Unrepaired cyanotic– For 6 months following repair with prosthetic

material – Following incomplete repair with prosthetic

material• Transplant recipient with abnormal valves

Valvular Heart Disease: The Mitral Valve

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