Valvular Heart Disease: The Aortic Valve

Case

• A 60 year old Asian female with a history of a heart murmur presents for a routine visit. She has no complaints.

• Vitals are normal. A 4/6 mid systolic murmur is noted at the left upper sternal border.

• An EKG shows no abnormalities.

Case

• What is the next best step?– Do nothing, this murmur is benign– Do an exercise stress test to try to elicit symptoms

of aortic stenosis.– Do nothing, the patient has had this murmur for a

long time– Check an echocardiogram– Refer the patient to a cardiologist for further

evaluation

Case I: Echocardiogram

Case

• What is the next best step– Do nothing because aortic stenosis is not severe– Start a beta blocker and ACE-I for optimal blood

pressure control– Refer the patient to a cardiac surgeon for repair – Refer the patient to a cardiologist for further

evaluation

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

Aortic Valve Stenosis

• Obstruction of LV outflow• Common causes

– Bicuspid– Degenerative calcific– Rheumatic

• Rare causes– Congenital– Severe aortic atherosclerosis– Rheumatoid– Alkaptonuria

Flather. Lancet, 2000.

Aortic Valve Characteristics

• Normal Aortic Valve– Valve area 3-4 cm2

• Valve stenosis– 25% of normal valve area

• Hemodynamic Progression– 0.12 cm2/year– 0.32 m/s increase in jet velocity/year– 7 mmHg increase in mean gradient/year

Epidemiology

• Most common disease in western world– 50,000 valve replacements annualy– Age 65: 2% of patients– Age >80: >4%– 1 billion dollars annually in US

Etiologies of Aortic Stenosis

Baumgartner. JASE, 2009.

Etiologies of Aortic Valve Disease

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

Bicuspid Valve• 1-2% of births• Generalized arteriopathy: fragmentation of fibers of

the elastic media– Coarctation, aortic dilation, dissection (5-9x risk)

• Most common reason for valve replacement <70 years old

• Roughly 66% of replaced valves < 70 • More common in men: 70-80% of cases• Hemodynamic abnormalities predispose to earlier

stenosis

Roberts. Circulation, 2005.

Bicuspid Aortic Valve

Calcific AS

• Most common cause of AS• Present in 2% of adults 65 or older• Becomes symptomatic age 60-80• Sclerosis present in 29% ≥ 65 • Proliferative and inflammatory changes->

calcification and bone formation• Risk Factors: HL, tob, HTN, DM

Rheumatic AS

• Adhesions and fusion of commisures and cusps

• Vascularization of leaflets-> retraction and stiffening of the free borders of the cusps

• Calcific nodules• Small triangular orifice• Coexists with rheumatic mitral valve disease

Time Between Rheumatic Fever and Symptoms of Stenosis

Development of AS

Otto. NEJM. 2008.

Pathophysiology of AS

• Progressive obstruction and compensatory change

• Pressure overload->increased wall stress->increased wall thickness

• Increased myocardial collagen• Progressive systolic dysfunction• Progressive diastolic dysfunction• Decreased coronary blood flow

Pathophysiology

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

Law of Laplace

Yousef. BMJ. 1999.

Pathologic LV Hypertrophy

Sorajja. Contemporary Cardiology, 2009.

Clinical Course

• Outcome similar to normal in asymptomatic patients

• Progression from sclerosis to severe AS: 2.5% in 8 years

• Mortality is high in patients with symptomatic disease

Cosmi. Arch Int Med. 2002.

Progression of Asymptomatic AS

Otto. Circulation. 1997.

Mortality In Symptomatic Aortic Stenosis Is High

Levy. NEJM, 2002.Ross J Jr, Braunwald E: Aortic stenosis. Circulation 38:V61, 1968

Survival With Or Without Valve Replacement

Carabello. NEJM, 2002.Schwarz. Circulation, 1982.

Clinical Presentation

• Age– Bicuspid: 50-70 years old – Calcific: > 70 years old

• Symptoms– Progressive exercise intolerance– Angina (2/3 with significant CAD)– Syncope– Endocarditis, systemic embolization

Physical Examination• Carotid upstroke

– Parvus and tardus: slow rising, late peaking

– Specific but insensitive• Systolic murmur

– Late peaking heard at the base• Varies beat to beat• Louder with increased flow:

squatting• Quieter with decreased flow:

standing– Stops before A2– Can radiate to the apex

(Gallivardin phenomenon)• Second heart sound

– Absent A2 with severe disease• Signs of heart failure

Libby. Braunwald’s Cardiology. 8th Ed.

Aortic Stenosis Carotid Pulse Waveforms

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

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 ↑↑ ↑ ↓ ↑

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

EKG and CXR

• EKG– LVH– Atrial enlargement– Conduction abnormalities

• Chest XR– Rounding of LV border and apex

Further Assessment

• Unclear symptoms– Treadmill exercise testing

• Development of symptoms• Failure to increase BP > 10 mmHg• NOT IN SYMPTOMATIC PATIENTS

• Low left ventricular function– Dobutamine infusion

Low Cardiac Output: Response to Dobutamine Infusion

Sorajja. Contemporary Cardiology, 2009.

Increase in CO and grad.No change in AVA.

Increase in CO.No change in grad.

No change in CO, dec grad and hypotension.

Echocardiogram in AS

• Valve anatomy definition• LV hpertrophy and systolic function• Transaortic velocities and gradients

Echo Assessment of Aortic Stenosis

Baumgartner. JASE, 2009.

Severity of Aortic Stenosis

Mild Moderate Severe

Jet Velocity (m/s) 2.6-2.9 3.0-4.0 >4.0

Mean gradient (mmHg)

<20 20-40 >40

AVA (cm2) >1.5 1.0-1.5 <1.0

Baumgartner. JASE, 2009.

Medical Therapy For Aortic Stenosis

Bonow. JACC, 2006.

Non-Operative Management of Aortic Stenosis

• Counseling to monitor for symptoms• Evaluate and treat CAD• Reassessment

– For symptoms changes– Severe: Annually– Moderate: 1-2 years– Mild 3-5 years

• Balloon valvulotomy

When To Refer To Cardiology

• All symptomatic• AS with LV dysfunction• Asymptomatic progressive disease• Atypical presentations

Operative Management Of AS• Class I

– Symptomatic– Severe AS undergoing cardiac surgery– Severe AS and EF < 50%

• Class II– Moderate AS undergoing cardiac surgery– Asymptomatic with severe AS and abnormal ex response– Asymptomatic severe with risk of rapid progression– Mild AS undergoing cardiac sx, concern for rapid

progression– Very severe asymptomatic with low op mortality

Surgical Mortality

• 3-4% for AVR alone• 5.5-6.8% with AVR plus CABG• 33% increased mortality in low volume centers

Surgical Risk Calculator

www.sts.org/sections/stsnationaldatabase/riskcalculator/

euroscore.org/

Transcatheter Aortic Valve Replacement May Be An Option For

High Risk Patients

http://www.edwards.com/eu/products/transcathetervalves/sapienthv.htm

Transcatheter Aortic Valve Replacement For High Risk Patients

Leon. NEJM, 2010.

Aortic Regurgitation• Leaflets (46%)

– Degenerative (75% with some AR)

– Endocarditis– Trauma– Congenital– Rhematic– Myxomatous– Systemic disorders: SLE, giant

cell and Takayasu’s, ankylosing spondylitis, Whipple’s, Chron’s, weight loss drugs

• Aorta (54%)– Age– Degenerative disease (Marfan)– Dissection – HTN– Syphilis– Ankylosing spondylitis– Giant cell arteritis– Behcet syndrome– Psoriatic arthritis– Osteogenesis imperfecta– Reieter syndrome – Relapsing poychondritis

Rigolin. Contemporary Cardiology, 2009. Roberts. Circulation, 2006.

Pathophysiology

• LF ejection split between forward and back• Total stroke volume is increased• Left ventricle dilates to accommodate stroke

volume• Increased LVEDP and hypertension ->

increased preload and afterload -> eccentric hypertrophy

• Mismatch-> systolic dysfunction -> fibrosis-> dysfunction becomes permanent

Pathophysiology

Libby. Braunwald’s Cardiology. 8th Ed.

Clinical Presentation

• Long asymptomatic period• LV dysfunction -> EDV and EDP increase• Increase right sided pressures• Cardiac output falls• Exercise tolerance develops

Physical Exam• Findings secondary to

increased stroke volume and widened pulse pressure

• Apical impulse: diffuse, laterally-inferiorly displaced, hyperdynamic

• Carotid pulse: Corrigan’s, bifid• S1 normal, S2 variable• LSB blowing diastolic murmur,

Austin Flint murmur

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

Peripheral Signs of AI

Rigolin. Contemporary Cardiology, 2009.

LVH and Strain In Aortic Regurgitation

Rigolin. Contemporary Cardiology, 2009.

Cardiomegaly In Aortic Regurgitation

Rigolin. Contemporary Cardiology, 2009.

Echo Assessment Of AI

• LA size• Leaflet appearance• Jet width, density,

deceleration, diastolic flow reversal

• VC width, calculated regurgitant volume and EROA

Zoghbi. JASE, 2003.

Echo Assessment Of AI

Zoghbi. JASE, 2003.

Aortic Regurgitation Clinical Course

Bonow. JACC, 2006.

Medical Therapy• Class I recommendation

– Severe AR with symptoms or LV dysfunction and unable to undergo surgery

• Class IIa– Bridge to surgery in patients with severe LV dysfunction

• Class IIb– Long term in severe AR with LV dilation but normal

function• Hydralazine, nifedipine have been studied

No Benefit To Vasodilators In Asymptomatic AR

Evangelista. NEJM, 2005.

Survival After AI Repair By Pre-Op EF

Rigolin. Contemporary Cardiology, 2009.

Bonow. JACC, 2006.