Echocardiographic Echocardiographic Evaluation of Prosthetic Evaluation of Prosthetic

Heart ValvesHeart Valves

Patricia Tung, M.D.Patricia Tung, M.D.

February 10, 2010February 10, 2010

ObjectivesObjectives

Types of prosthesesTypes of prostheses Prosthetic dysfunctionProsthetic dysfunction Echocardiographic surveillance of Echocardiographic surveillance of

prosthesesprostheses

Types of ProsthesesTypes of Prostheses

Mechanical valvesMechanical valves Tissue valvesTissue valves Homograft valvesHomograft valves

Mechanical ValvesMechanical Valves

Tissue ValvesTissue Valves

Homograft ValvesHomograft Valves

ObjectivesObjectives

Types of prosthesesTypes of prostheses Prosthetic dysfunctionProsthetic dysfunction Echocardiographic surveillance of Echocardiographic surveillance of

prosthesesprostheses

Mechanisms of Prosthetic Valve Mechanisms of Prosthetic Valve DysfunctionDysfunction

Structural failureStructural failure StenosisStenosis RegurgitationRegurgitation

Thromboembolic complicationsThromboembolic complications EndocarditisEndocarditis Patient Prosthesis MismatchPatient Prosthesis Mismatch

Structural Failure BioprostheticsStructural Failure Bioprosthetics

Cohn et al. Ann Thorac Surg, 1998.

Homograft DysfunctionHomograft Dysfunction

Subject to severe tissue calcification Subject to severe tissue calcification Usually reserved for complex aortic root Usually reserved for complex aortic root

abscessesabscesses Hyperlipidemia accelerates prosthesis Hyperlipidemia accelerates prosthesis

calcificationcalcification Secondary prevention may slow this Secondary prevention may slow this

process process

Physical Exam FindingsPhysical Exam Findings

TTETTE valve area and regurgitationvalve area and regurgitation exclude significant obstruction exclude significant obstruction Flow velocity is crucial measurementFlow velocity is crucial measurement Often inadequate for infection or small structural changes (strut fracture, small Often inadequate for infection or small structural changes (strut fracture, small

vegetation, paravalvular leak)vegetation, paravalvular leak)

TEETEE inspection of valve apparatus and seatinginspection of valve apparatus and seating may not accurately quantify valve flow velocitiesmay not accurately quantify valve flow velocities

Echocardiographic EvaluationEchocardiographic Evaluation

Normal Appearance PVNormal Appearance PV

Normal Doppler ClicksNormal Doppler Clicks

Normal Doppler Flow PatternsNormal Doppler Flow Patterns

Fluid Dynamics and VelocitiesFluid Dynamics and Velocities

Normal Finding: RegurgitationNormal Finding: Regurgitation

Pathologic RegurgitationPathologic Regurgitation

Characterized by:Characterized by: An eccentric or large jetAn eccentric or large jet Marked variance on the color flow displayMarked variance on the color flow display A jet that originates around the valve sewing A jet that originates around the valve sewing

ringring Visualization of a proximal flow acceleration Visualization of a proximal flow acceleration

region on the LV side of the mitral valveregion on the LV side of the mitral valve

Prosthetic Valve RegurgitationProsthetic Valve Regurgitation

Prosthetic Valve StenosisProsthetic Valve Stenosis

Pressure gradientsPressure gradients- Calculated using the Bernoulli equation (4vCalculated using the Bernoulli equation (4v22))- Good correlation when validated against Good correlation when validated against

invasive pressure measurementsinvasive pressure measurements- mechanical valves, especially bileaflet, result mechanical valves, especially bileaflet, result

in overestimation of the gradient due to in overestimation of the gradient due to differing fluid dynamics differing fluid dynamics

Prosthetic Aortic Valve AreaProsthetic Aortic Valve Area

Prosthetic AVA: Velocity RatioProsthetic AVA: Velocity Ratio

Measure velocity increase across valveMeasure velocity increase across valve Ratio of outflow tract velocity/aortic jet Ratio of outflow tract velocity/aortic jet

velocity reflects degree of stenosisvelocity reflects degree of stenosis Ratio = 1 if no obstruction presentRatio = 1 if no obstruction present Given inherent stenosis, normal range is Given inherent stenosis, normal range is

0.35 to 0.5 for aortic prosthesis0.35 to 0.5 for aortic prosthesis

Prosthetic Mitral Valve AreaProsthetic Mitral Valve Area

Can be estimated using the pressure half-Can be estimated using the pressure half-time approach as for native mitral valve time approach as for native mitral valve stenosis.stenosis.

The expected half-time for a PV is longer The expected half-time for a PV is longer than with a native valve.than with a native valve.

Prosthetic Valve ThrombosisProsthetic Valve Thrombosis

TEE is often negative if the TEE is often negative if the thrombi are small or if new thrombi are small or if new thrombus has not formed thrombus has not formed since the initial embolic since the initial embolic event.event.

Thus an embolic event in a Thus an embolic event in a patient with a prosthetic patient with a prosthetic valve (esp mechanical) valve (esp mechanical) must be presumed to be must be presumed to be related to the PV even if the related to the PV even if the TEE is negative.TEE is negative.

Prosthetic Valve EndocarditisProsthetic Valve Endocarditis

Difficult to detect with TTEDifficult to detect with TTE Often involves sewing ring and annulus, Often involves sewing ring and annulus,

resulting in paravalvular abscess rather resulting in paravalvular abscess rather than a discrete vegetationthan a discrete vegetation

Prosthetic Valve EndocarditisProsthetic Valve Endocarditis

Patient Prosthesis MismatchPatient Prosthesis Mismatch

Size of prosthesis results in inadequate Size of prosthesis results in inadequate blood flow given metabolic demandsblood flow given metabolic demands

Prosthesis itself functions wellProsthesis itself functions well Indexed effective orifice area < or = Indexed effective orifice area < or =

0.85cm2/m20.85cm2/m2 Predicts high transvalvular gradients, Predicts high transvalvular gradients,

persistent LVH and increased rate of persistent LVH and increased rate of cardiac events following AVRcardiac events following AVR

ObjectivesObjectives

Types of prosthesesTypes of prostheses Prosthetic dysfunctionProsthetic dysfunction Echocardiographic surveillance of Echocardiographic surveillance of

prosthesesprostheses

Recommended SurveillanceRecommended Surveillance Baseline echocardiogram 6-8 weeks Baseline echocardiogram 6-8 weeks

postoperativelypostoperatively Routine echocardiographic surveillance Routine echocardiographic surveillance

annually thereafterannually thereafter Evaluate forEvaluate for

Regression of hypertrophy or dilationRegression of hypertrophy or dilation Recovery of LV systolic functionRecovery of LV systolic function Changes in PA pressuresChanges in PA pressures

SummarySummary Prosthetic valve dysfunction is well detected by Prosthetic valve dysfunction is well detected by

echocardiographyechocardiography Dysfunction includesDysfunction includes

Structural failureStructural failure Thromboembolic complicationsThromboembolic complications EndocarditisEndocarditis PPMPPM

Distinguishing normal from pathologic function Distinguishing normal from pathologic function can be challenging; most useful is comparison to can be challenging; most useful is comparison to baseline post-prosthesis baseline post-prosthesis

ReferencesReferences Otto, C. Textbook of Clinical Echocardiography, Fourth Edition Otto, C. Textbook of Clinical Echocardiography, Fourth Edition

2009.2009. Libby et al. Braunwald’s Heart Disease. Eighth Edition 2008.Libby et al. Braunwald’s Heart Disease. Eighth Edition 2008. Pibarot, P and Dumesnil JG. Prosthesis-patient mismatch: Pibarot, P and Dumesnil JG. Prosthesis-patient mismatch:

definition, clinical impact, and prevention. Heart 2006;92:1022-1029 definition, clinical impact, and prevention. Heart 2006;92:1022-1029 Bonow RO, Carabello BA, Chatterjee K, et al:  ACC/AHA 2006 Bonow RO, Carabello BA, Chatterjee K, et al:  ACC/AHA 2006

guidelines for the management of patients with valvular heart guidelines for the management of patients with valvular heart disease: A report of the American College of Cardiology/American disease: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 Guidelines for the Management of committee to revise the 1998 Guidelines for the Management of Patients with Valvular Heart Disease): Developed in collaboration Patients with Valvular Heart Disease): Developed in collaboration with the Society of Cardiovascular Anesthesiologists: endorsed by with the Society of Cardiovascular Anesthesiologists: endorsed by the Society for Cardiovascular Angiography and Interventions and the Society for Cardiovascular Angiography and Interventions and the Society of Thoracic Surgeons.   the Society of Thoracic Surgeons.   CirculationCirculation   2006; 114:e84.    2006; 114:e84.