Indications for Aortic Valve Replacement

Tim Brinker

Overview

• Anatomy• Aortic Stenosis and Aortic Insufficiency

-Etiology-Signs/Symptoms-Diagnostic Studies-Indications for Surgical Intervention

Normal Anatomy

• 3 semilunar valve leaflets (right, left, and posterior)

• Normal Aortic valve has cross sectional area of 2.5 to 3.5 cm2.

Aortic Stenosis

• Etiology– Degenerative calcific disease– Congenital Stenosis– Bicuspid Aortic Valve– Rheumatic Heart Disease

Signs and Symptoms

• Most patients remain asymptomatic for years.

• Classic Triad– Angina Pectoris– Syncope– Congestive Heart FailureOther symptoms include hypertension and

dyspnea.

NYHA Classification

• Class I – Symptomatic only with greater than normal activity.

• Class II – Symptomatic with ordinary activity.

• Class III – Symptomatic with minimal activity.

• Class IV – Symptomatic at rest.

Physical Exam

• High pitched systolic crescendo-decrescendo murmur at RUSB and radiates to the carotids.

• Decreases with Valsalva maneuver.• Increases with passive leg raise• Ejection click with bicuspid aortic valve

Diagnostic Studies• CXR – Normal size or cardiomegaly. May see

calcification of the valve in older individuals.• EKG – Demonstrates LVH.• ECHO – Can evaluate calcification and mobility

of aortic valve leaflets, anatomy and aortic valve area, LVH, EF, transvalvular gradients, and aortic regurgitation.

• Cardiac Catheterization – Reveals coronary anatomy, CO, transvalvular gradients, LV function, presence of other valvular lesions. Indicated in patients suspected of having CAD in preparation for AVR.

• Exercise Testing – May elicit exercise-induced symptoms and abnormal bp responses in asymptomatic patients.

Bonow, RO, Carabello, BA, Chatterjee, K, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing committee to revise the 1998 guidelines for the

management of patients with valvular heart disease). Journal of the American College of Cardiology 2006; 48:e1.

Low Gradient Aortic Stenosis

• AVA <1.0 cm2 with TVPG <30 mmHg

Dobutamine or Nitroprusside can distinguish between true stenosis and psuedostenosis.

Operative Indications

• Surgery (Aortic Valve Replacement)– Symptomatic Severe Aortic Stenosis– Asymptomatic severe Aortic Stenosis with

decreased EF (<0.50), AVA <0.6cm2, aortic jet >4m/s, or decreased BP with exercise

– Asymptomatic moderate-severe Aortic Stenosis and undergoing CABG.

Medical Treatment

Antibiotic prophylaxis for infective endocarditis and recurrent rheumatic fever.

If patient is symptomatic and not an operative candidate– Gentle Diuresis, control of HTN

(ACEI,dig,statin)– Avoid venodilators (nitrates) and neg

ionotropes (BB, CCB) in severe AS

Prognosis

• Angina – 5 year survival• Syncope – 3 year survival• CHF – 2 year survival

Aortic Insufficiency

• Etiology– Degenerative diseases– Inflammatory or infectious disease

(endocarditis, rheumatic fever)– Congenital diseases (bicuspid valve)– Aortoannular ectasia– Aneurysm of the aortic root– Aortic dissection

Signs and Symptoms

• May be asymptomatic• Dyspnea on exertion, decreased exercise

capacity• Palpitations• Angina• Pulmonary edema• Right heart failure

Physical Exam

• Diastolic decrescendo murmur at LUSB• Severity proportional to duration of

murmur.• Wide pulse pressure (decrease in diastolic

pressure)• Austin Flint murmur – diastolic rumble at

apex

Diagnostic Studies

• CXR – cardiomegaly ,+/- aortic dilation• EKG – may show LVH or A-fib• ECHO – Measures degree of valvular

insufficiency, LV size and function.• Exercise test – assess functional capacity and

symptomatic response.• May perform aortic root angiography or MRI if

aneurysmal disease is suspected.

Bonow, RO, Carabello, BA, Chatterjee, K, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease. A report of the American College of

Cardiology/American Heart Association Task Force on Practice Guidelines (Writing committee to revise the 1998 guidelines for the management of patients with valvular heart disease). Journal of the American College of Cardiology 2006; 48:e1.

Operative Indications

• Surgery (Aortic Valve Replacement)– Symptomatic severe AI– Asymptomatic severe AI and EF <50% or LV

systolic diameter >55mm or diastolic diameter >75mm

– Asymptomatic severe AI and undergoing CABG.

Medical Therapy

• Vasodilators (nifidepine, ACEI, hydralazine) if severe AI, HTN, or patient is not an operative candidate.

• Diuretics and Digoxin if patient with CHF.

Operative Techniques

• Aortic Valve Replacement– Median sternotomy incision– Cardiopulmonary bypass is used.– Aortic valve is excised totally.– Mechanical valves (single tilting or bileaflet

disk). Patients require lifelong anticoagulation.

– Tissue valves (have projected durability of 15 years or longer with no anticoagulation).

• Ross Procedure– Involves replacement of the aortic valve with

an autograft from the patient’s native pulmonary valve. The pulmonary valve is then replaced with a pulmonary homograft.

– Patients do not require long term anticoagulation.

Take Home Points• In symptomatic AS patients, AVR improves

symptoms and improves survival• AVR is indicated in virtually all symptomatic

patients with severe AS.• AVR is indicated in patients with symptomatic AI

or with LV dysfunction (EF<0.50 at rest)• AVR is not indicated in asymptomatic patients

with normal LV function (EF>0.50) and LV dilation in AI