Non-Invasive Non-Invasive Assessment of Assessment of

Prosthetic ValvesProsthetic Valves

November 21, 2007November 21, 2007

Alex MorssAlex Morss

Terms and definitionsTerms and definitions

Prosthetic valves: manmade Prosthetic valves: manmade replacements of heart valves, either replacements of heart valves, either mechanical (nonorganic) or bioprosthetic mechanical (nonorganic) or bioprosthetic (organic materials used in construction, (organic materials used in construction, i.e. animal or human parts)i.e. animal or human parts)

Assessment: visual evaluationAssessment: visual evaluation Non-invasive: taking pictures of hidden Non-invasive: taking pictures of hidden

things without using sharp objects (i.e., things without using sharp objects (i.e., essentially nonviolent means of seeing essentially nonviolent means of seeing them undressed)them undressed)

Main Characters Main Characters (Protagonists)(Protagonists)

Mechanical ValvesMechanical Valves Ball-cage Ball-cage Tilting discTilting disc BileafletBileaflet

Bioprosthetic ValvesBioprosthetic Valves StentedStented Unstented (aortic root)Unstented (aortic root) Homograft, allograftHomograft, allograft

The AntagonistsThe Antagonists

Endocarditis +/- vegetationsEndocarditis +/- vegetations Paravalvular leak (+/- dehiscence)Paravalvular leak (+/- dehiscence) ThrombosisThrombosis Pannus formationPannus formation Degeneration, +/- calcific stenosis or Degeneration, +/- calcific stenosis or

leaflet tearleaflet tear Strut fracture, disc embolizationStrut fracture, disc embolization Unseating of valveUnseating of valve

The ArsenalThe Arsenal

Roentgenography (X-Roentgenography (X-Ray)Ray)

FluoroscopyFluoroscopy Cardiac MRI (?)Cardiac MRI (?) EchocardiographyEchocardiography

TTE will often best allow TTE will often best allow optimal Doppler anglesoptimal Doppler angles

TEE will often best TEE will often best allow optimal direct allow optimal direct visualizationvisualization

IntangiblesIntangibles

The Main CharactersThe Main Characters Mechanical ValvesMechanical Valves

Ball-cage (Starr-Ball-cage (Starr-Edwards)Edwards)

Tilted-disc (Bjork-Tilted-disc (Bjork-Shiley, Medtronic-Hall)Shiley, Medtronic-Hall)

* Note: the convexoconcave * Note: the convexoconcave version of the Bjork-Shiley version of the Bjork-Shiley valve earned a bad name due valve earned a bad name due to cases of strut fracture and to cases of strut fracture and disc embolizationdisc embolization

Bileaflet (St. Jude, Bileaflet (St. Jude, Carbomedics)Carbomedics)

All valves are sized by All valves are sized by diameter, 19-33 mmdiameter, 19-33 mm

O’Neill NEJM 1995

Main Characters, Part Main Characters, Part DeuxDeux

Bioprosthetic Bioprosthetic ValvesValves Stented: Carpentier-Stented: Carpentier-

Edwards, Hancock, Edwards, Hancock, Ionescu-Shiley, St. Ionescu-Shiley, St. Jude MosaicJude Mosaic

Stentless: Biocor.Stentless: Biocor. Homografts/Homografts/

autografts: may not autografts: may not be able to detect be able to detect noninvasivelynoninvasively

Also sized by Also sized by diameter, 19-33 mmdiameter, 19-33 mm

Hancock

Mosaic

Stentless porcine

Unveiling the arsenalUnveiling the arsenalOld School: RoentgenographyOld School: Roentgenography

Mechanical and many Mechanical and many stented bioprosthetic stented bioprosthetic valves are radiopaque, valves are radiopaque, allowing allowing determination of valve determination of valve type and position on type and position on chest X-ray.chest X-ray.

May be used to assess May be used to assess for device fracture in for device fracture in some casessome cases Starr-Edwards valve seen in aortic position

in 1965. From Nery, Heart 2004

Up a Notch: FluoroscopyUp a Notch: Fluoroscopy Best methodology to Best methodology to

assess mechanical assess mechanical leaflet motion due to leaflet motion due to outstanding spatial outstanding spatial and temporal and temporal resolution.resolution.

May be used to May be used to assess stability of assess stability of valve ring with the valve ring with the cardiac cyclecardiac cycle

May optimally May optimally position angle to best position angle to best assess subtle fractureassess subtle fracture

O’Neill NEJM 1995

Disc embolizationDisc embolization

O’Neill NEJM 1995

disc

Cardiac MRICardiac MRI

Cardiac MRI may Cardiac MRI may visualize mechanical visualize mechanical valves, but lacks the valves, but lacks the temporal resolution temporal resolution and Doppler and Doppler capablities of capablities of echocardiographyechocardiography

May show gross May show gross valve position, valve position, function, and function, and regurgitationregurgitation

More cardiac MRIMore cardiac MRI

EchocardiographyEchocardiography TransthoracicTransthoracic

Allows assessment of valve area and regurgitation Allows assessment of valve area and regurgitation via Doppler, which is generally adequate to via Doppler, which is generally adequate to exclude significant obstructive or regurgitant exclude significant obstructive or regurgitant change. Flow velocity is the crucial measurement. change. Flow velocity is the crucial measurement.

Inadequate to assess infection or small structural Inadequate to assess infection or small structural changes (e.g. strut fracture, small vegetation, changes (e.g. strut fracture, small vegetation, paravalvular leak)paravalvular leak)

TransesophagealTransesophageal Ideal for visual inspection of valve apparatus and Ideal for visual inspection of valve apparatus and

seating; may not accurately quantify valve flow seating; may not accurately quantify valve flow velocities. May directly measure aortic valve area velocities. May directly measure aortic valve area via planimetryvia planimetry

Echo by valve positionEcho by valve position AorticAortic

Accurate TTE assessment relies on accurate Doppler Accurate TTE assessment relies on accurate Doppler assessments in multiple viewsassessments in multiple views

Often many TTE views partially obscured by shadowing. Often many TTE views partially obscured by shadowing. Often TEE required to view leaflets Often TEE required to view leaflets

MitralMitral Among the best positions for TTE visualization, usually Among the best positions for TTE visualization, usually

able to see leaflets via apical viewsable to see leaflets via apical views TricuspidTricuspid

Also usually adequately visualized by TTE directly and Also usually adequately visualized by TTE directly and via Dopplervia Doppler

PulmonicPulmonic Rarest position for valve replacement. Difficult to Rarest position for valve replacement. Difficult to

visualize for both TTE and TEE, no clear advantagevisualize for both TTE and TEE, no clear advantage

Aortic ProsthesesAortic Prostheses

Focus on Doppler imaging of aortic outflows to Focus on Doppler imaging of aortic outflows to determine mean and peak gradientsdetermine mean and peak gradients

Can identify prosthesis type by direct Can identify prosthesis type by direct visualizationvisualization

As with all prostheses, need to know their SIZE As with all prostheses, need to know their SIZE to allow assessment of normal vs. to allow assessment of normal vs. pathologically increased transvalvular pathologically increased transvalvular gradient. gradient.

Size varies from 19-29 mm in diameterSize varies from 19-29 mm in diameter Normal gradients for each valve type and size Normal gradients for each valve type and size

may be found on reference tablesmay be found on reference tables

Normal aortic bileaflet Normal aortic bileaflet valvevalve

Peak gradient 20mmHg, mean 12 mmHgPeak gradient 20mmHg, mean 12 mmHg Normal bileaflet gradients are dependent Normal bileaflet gradients are dependent

on valve sizeon valve size

Normal mechanical aortic Normal mechanical aortic valve peak gradientsvalve peak gradients

BileafletBileaflet 19mm: 33 +/- 1119mm: 33 +/- 11 29mm: 13 +/- 529mm: 13 +/- 5

Tilting discTilting disc 19mm: 4619mm: 46 29mm: 12+/- 829mm: 12+/- 8

Ball-cageBall-cage 23mm: 33+/-1323mm: 33+/-13 29mm: 29+/-929mm: 29+/-9

Full tables are available in echo texts or on fellowship echo website

Feigenbaum 2005

Approximate flow velocities:

19mm 2.9 m/sec

29 mm 1.9 m/sec

(+/- 0.5 m/sec)

Normal aortic Normal aortic bioprosthetic valvebioprosthetic valve

Peak gradient 17mm- need valve size and ideally baseline Peak gradient 17mm- need valve size and ideally baseline gradient at time of valve implantation to assess for normal gradient at time of valve implantation to assess for normal valuevalue

May also use continuity equation with measurement of May also use continuity equation with measurement of LVOT to calculate effective aortic valve areaLVOT to calculate effective aortic valve area

Tilting disc AVRTilting disc AVR

Ball-cage AVRBall-cage AVR

Name the AVR typeName the AVR type

Aortic bioprosthetic valve with paravalvular Aortic bioprosthetic valve with paravalvular leak, valvular regurgitationleak, valvular regurgitation

What’s wrong?What’s wrong?

Tilting disc valve with thrombosis causing partial obstruction

Talley, Can J Card 1986

Mitral prosthetic valvesMitral prosthetic valves

Better visualization on TTEBetter visualization on TTE Much lower normal gradients than Much lower normal gradients than

aortic valves due to lower flow aortic valves due to lower flow velocities and larger size overallvelocities and larger size overall

Sizes generally vary from 25-33mm Sizes generally vary from 25-33mm in diameterin diameter

Normal bioprosthetic Normal bioprosthetic MVRMVR

Peak mitral velocity of 1.30 m/sec, peak gradient 8 mmHg, Peak mitral velocity of 1.30 m/sec, peak gradient 8 mmHg, mean 5mmHg (normal ~ 5 depending on valve size)mean 5mmHg (normal ~ 5 depending on valve size)

Bileaflet MVRBileaflet MVR

Appropriate regurgitation shown- 2 jets in bileaflet valveAppropriate regurgitation shown- 2 jets in bileaflet valve By design in mechanical valves to minimize thrombosis By design in mechanical valves to minimize thrombosis

riskrisk

Ball-cage MVRBall-cage MVR

Cage-ball valves have the highest nomalvalve gradients due to design

Mean gradient 9 mmHgMean gradient 9 mmHg Standard mean gradient for ball-cage Standard mean gradient for ball-cage

MVR is 5-7 +/- 3, depending on sizeMVR is 5-7 +/- 3, depending on size

Mitral endocarditisMitral endocarditis

Kort, JASE 2006 (from Gelfand)

Mitral unpleasantries, Mitral unpleasantries, part IIpart II

A league of its ownA league of its own

SummarySummary Valve type and position often easily determined on CXRValve type and position often easily determined on CXR Fluoroscopy optimal for assessing mechanical valve Fluoroscopy optimal for assessing mechanical valve

leaflet motion, unable to see bioprosthetic leafletsleaflet motion, unable to see bioprosthetic leaflets TTE may identify flow velocities and gross structure, TTE may identify flow velocities and gross structure,

best suited for MVR and exclusion of obstruction due to best suited for MVR and exclusion of obstruction due to good Doppler views. Doppler velocities and valve good Doppler views. Doppler velocities and valve gradients are likely better than calculation of valve gradients are likely better than calculation of valve area due fewer variablesarea due fewer variables

TEE allows better visualization of smaller structural TEE allows better visualization of smaller structural changes, vegetations, and paravalvular leaks. It is the changes, vegetations, and paravalvular leaks. It is the study of choice for concerns of endocarditis in any study of choice for concerns of endocarditis in any prosthetic valve.prosthetic valve.

CMR limited role and not generally used to assess CMR limited role and not generally used to assess prosthetic valves.prosthetic valves.

Thank you!