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 Class III 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 FIGURE 25-1 Prevalence rates of heart failure by gender and age in the United States between 1988 and 1994—the Third National Health and Nutrition Examination Survey (NHANES III). Among men (blue), the prevalence increased from 18 cases per 1000 in those aged 45 to 54 years to 98 cases per 1000 in those aged 75 years and older. Among women (purple), the prevalence increased from 13 cases per 1000 in those aged 45 to 54 years to 97 cases per 1000 in those aged 75 years and older.  (Data from American Heart Association: Heart Disease and Stroke Statistics—2003 Update. Dallas, American Heart Association, 2002.) 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 Libby. Braunwald’s Heart Disease. 8th Ed.

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 Heart failure 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 Unchanged Exercise Amyl nitrite ↑↑ Isoproterenol Libby. Braunwald’s Heart Disease. 8th Ed.

XR Findings Prominent left atrial enlargement Left ventricular enlargement Pulmonary edema in acute MR Enriquez-Serano. Contemporary Cardiology, 2009.

Atrial Fibrillation Affects 50% of Patients Within 10 Years Enriquez-Serano. Contemporary Cardiology, 2009.

Acute Mitral Regurgitation Elevated PAP and Large PCWP V Waves Libby. Braunwald’s Heart Disease. 8th Ed.

Variable Presentations of Mitral Regurgitation Enriquez-Serano. Contemporary Cardiology, 2009.

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 Mild Moderate Severe Enriquez-Serano. Contemporary Cardiology, 2009.

Mitral Valve Prolapse Repair Foster. NEJM. 2010.

Prosthetic Mitral Valve Bloomfield. Heart, 2002.

Survival After Surgical Correction By EF Libby. Braunwald’s Heart Disease. 8th Ed.

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

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 Exam findings 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 Expected survival Mitral stenosis Mitral regurgitation Libby. Braunwald’s Heart Disease. 8th Ed.

Management Approach to Mitral Stenosis Nobuyoshi. Circulation, 2009.

Percutaneous Valvuloplasty Nobuyoshi. Circulation, 2009.

Long Term Outcome For Percutaneous Valvuloplasty Libby. Braunwald’s Heart Disease. 8th Ed.

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