SURGICAL TREATMENT FOR VALVULAR HEART DISEASE

1Susan Raaymakers, MPAS, PA-C, RDCS (AE)Susan Raaymakers, MPAS, PA-C, RDCS (AE)

(PE)(PE)Grand Valley State University, Grand Rapids, Grand Valley State University, Grand Rapids,

MichiganMichiganraaymasu@gvsu.eduraaymasu@gvsu.edu

BACKGROUND Review

Rheumatic heart dz originates as throat infection from streptococcal infection Article in January 2009 JASE

Rheumatic heart disease was the leading cause of death 100 years ago in people aged 5-20 years in the United States Incidence just above 0% in developed countries

Chronic rheumatic heart disease is estimated to exist in 5-30 million children and young adults; 90,000 patients die from this disease each year. The mortality rate from this disease remains 1-10%

Occurs generally in children 5-15 years old but may present in adult 2

http://www.emedicine.com/ped/topic2007.htm

INITIAL SURGICAL TREATMENTS

First successful attempt at surgical treatment Incising the left atrial appendage, placing finger

through the incision into the left atrium, feeling the stenotic mitral and relieving the obstruction by simple finger pressure.

3

INITIAL SURGICAL TREATMENTS In the early days of cardiovascular surgery,

procedures were done on the beating heart

1950’s cardiac and pulmonary bypass machines were developed This development made it possible to keep the patient

alive while stopping the heart for surgical repair Ability to stop the heart allowed examination of valve

pathology and repair Stimulated surgeons’ collaboration with mechanical

engineers in developing prosthetic valves

4

Erector set heart pump, 1950 Using a toy Erector set, William Sewell Jr. and William W. L. Glenn, Yale University medical students, built this section of a heart pump,

which Sewell successfully used in experimental bypass surgery on dogs. Acquired in 1959 from

Sewell's mother, this heart pump is one of many invention prototypes in the Smithsonian

collections

INDICATIONS FOR SURGICAL REPAIR/REPLACEMENT OF VALVES

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FIRST GENERATION OF SYNTHETIC VALVES Era of valve surgery proceeded the development

of echocardiography by only a few years. 1960s One of the earliest applications of echocardiography was the

evaluation of prosthetic valves.

The first generation of synthetic valves retained in a cage Free-floating balls (mechanical ball and cage) or Disc occluders (caged disk)

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INDICATIONS

Valvular stenosis Valvular regurgitation Native valve endocarditis Aortic dissection with severe aortic

regurgitation

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VALVULAR REPLACEMENT8

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THREE TYPES OF PROSTHETIC HEART VALVES

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THREE TYPES OF PROSTHETIC HEART VALVES

MechanicalBioprostheticHomograft

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MECHANICAL VALVES

All mechanical valves haveA Sewing ring

Moving component Cage, strut or frame.

Made from a compressed carbon material •Hard enough and yet free of significant friction to provide long term durability •Providing relative freedom from wear, breakage or excessive clotting.

MECHANICAL VALVESTYPES Ball and Cage Caged Disc Tilting Disc Bileaflet Valved Conduit

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MECHANICAL VALVEBALL AND CAGE

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MECHANICAL VALVESBALL AND CAGEStarr-Edwards (used in the first

clinically successful valve replacement)Was most Common

Smeloff-Cutter Braunwald-Cutter Magovern-Surgitool Magovern-Cromie Harken DeBakey-Surgitool Hufnagel

15

MECHANICAL BALL AND CAGE

16Hufnagel

1952

Starr-Edwards in Mitral Position – introduced 1961

To open, the ball moves forward into the cage, allowing blood flow around the entire circumference. To occlude, the ball is driven back into the sewing ring to prevent backflow.

Smeloff-Cutter

STARR-EDWARDS VALVE IN MITRAL POSITION

17

•poppit

•moving forward and backward in the cage.

•Diastole,

•poppet moves forward allowing blood to flow around the occluder.

•These valves are highly echogenic, and small thrombi or vegetations can be easily hidden or overlooked.

14.5 Feigenbaum

FLOW PROFILEBALL AND CAGE Open position

Blood flows across sewing ring and around the ball occluder on all sides In Colorflow, observed as bilateral horns.

Closed positionSmall amount of regurgitation: circumferentially

around the ball as it seats in the sewing ring

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M-MODE STARR-EDWARDS FROM APEX

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SHORT-COMINGS OF BALL AND CAGE

1. Bulky in design and did not fit well into a small ventricle or aorta

2. Small internal orifice, making them relatively stenotic

3. Stimulated thrombus formation, which precipitated thromboembolic events, necessitating long-term anti-coagulation therapy 20

MECHANICAL VALVECAGED DISC

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MECHANICAL VALVE - CAGED DISCNO LONGER IN USE Beall-Surgitool

Was the most common Kay-Shiley Kay-Suzuki Cooley-Cutter Cross-Jones

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MECHANICAL VALVE - CAGED DISC

23Beall-Surgitool

Movable disc (discoid)

Disc elevated by very slight pressure to demonstrate closure

Cooley-Cutter

MECHANICAL VALVE - CAGED DISC

Advantage over ball and cage Caged disc occupied less area

Disadvantage Similar to ball and cage

Tissue overgrowth Chipping of the disc due to constant impact Mechanical problems

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MECHANICAL VALVESINGLE TILTING DISC

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MECHANICAL VALVE SINGLE TILTING DISC Most common

Medtronic-HallBjörk-Shiley

No longer available in U.S. due to the problem of strut fracture

Other tilting discsLillehei-KasterHall-KasterWada-CutterOmniscience Omnicarbon

26Van der Spuy "toilet seat" valveBlood tended to clot at the spring pivot of this valve.

http://www.hhmi.org/biointeractive/museum/exhibit98/content/h12info.html

MECHANICAL VALVE SINGLE TILTING DISC

27Björk-Shiley (1971 First Successful Tilting Disk)

Medtronic-Hall Pivoting Disc Valve

•Single disk prosthesis •Round sewing ring and a circular disk fixed eccentrically to the ring via a hinge.

• Disk moves through an arc of less than 90º allows:•Antegrade flow in the open position •Seating within the sewing ring to prevent backflow in the closed position.

FLOW PROFILE – SINGLE TILTING DISK

Open positionTwo orifices of unequal size (major vs. minor)

Asymmetric flow profile as blood accelerates along the tiled surface of the open disk

Subtle variations dependent on shape of disk (concave vs. convex) and sewing ring design

Closed positionSmall central jet of regurgitation occurs around

the central hole 28

COMPLICATIONS OF SINGLE TILTING DISCS Björk-Shiley had issues with strut fractures

619 of the 80,000 convexo-concave valves implanted fractured with patient death in 2/3 of cases

FDA removed from market in 1986 Perhaps the most infamous recall case on record

Hinge is eccentrically positioned within the sewing ring and the disk opens less than 90 degrees. Major and minor orifices are created and some

stagnation of flow occurs behind the disk. 29

BJORK-SHILEY

30

SINGLE TILTING DISCS Advantage

Low profile, can be inserted into aortic and mitral positions

Disadvantage High degree of leakage around central strut Region of stagnation behind disc

Thrombus formation Tissue overgrowth

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MECHANICAL VALVEBILEAFLET

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MECHANICAL VALVE - BILEAFLET St. Jude

Most frequently used mechanic valve Three orifices, which promote central flow Least stenotic mechanical prosthetic valve

Carbomedics Duromedics (Hemex) Gott-Daggett

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Non-dynamic

MECHANICAL VALVE - BILEAFLET

34St. Judehyperlink Carbomedics

• Opening angle is generally more vertical (approx 80º) than single disk prosthesis • Results in three distinct orifices:

• Two larger ones on either side and a smaller central rectangular-shaped orifice.

ST. JUDE MITRAL PROSTHESIS

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BI-LEAFLET MECHANIC VALVE

Colorflow profile Single large flow pattern or Two major jets on sides and one minor in middle.

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FLOW PROFILE - BILEAFLET

Complex fluid dynamics

Open positionTwo large lateral valve orifices with a small

narrow central “slitlike” orificeThree peak velocities corresponding to

three orifices Highest velocity in middle orifice Local gradients are often substantially higher than

overall valvular pressure

Closed positionTwo crisscross jets of regurgitation are seen

in plane parallel to the leaflet opening plane

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OVERALL COMPLICATIONS OF MECHANICAL VALVES

38

COMPLICATIONS OF MECHANICAL VALVES

Thrombus Indefinite anti-coagulation Stenosis

Thrombosis Pannus ingrowth

Fibrotic tissue which grows around a newly implanted prosthetic heart valve.

Vigorous growth of this healing tissue can freeze or obstruct a replacement valve.

May be related, in part, to the design or materials of the prosthesis, or to the degree of anticoagulation

Dehiscensce Infective endocarditis Hemolysis

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COMPLICATIONS OF MECHANICAL VALVESCONTINUED Mechanical failure

Ball/disc/cage variance/strut fracture

Heart-valve mismatch

Left ventricular outflow tract obstruction

Valve bed abnormalityPseudoaneurysm, valve ring abscess,

fistula, hematoma

RegurgitationCentral, perivalvular

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BIOPROSTHETIC VALVESConstructed from either human or animal tissue.

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BIOPROSTHETICVALVES Heterograft (xenograft)

Transfer from animal to humanLongest replaced approximately 10 yearsTypically replaced at 5 years

Auto-graft Transfer from self to self

Homograft (allograft)Transfer from one human to another

Last approximately 5 years 42

HETEROGRAFTTransfer from Animal to Human43

HETEROGRAFT (XENOGRAFT)PORCINE VALVES

Limited availability of heterograft prompted the use of porcine valves procured from slaughterhouses

Pig’s aortic valve is placed on stents, attached to a sewing ring and glutaraldehyde stabilized

Most common: Hancock I and II Carpentier-Edwards Intact (aortic)

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Hancock Porcine – Valve Closed

NORMAL FUNCTIONING PORCINE AORTIC PROSTHESIS

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•Leaflet opening during systole resembles that of a normal native valve.

•Overall appearance is similar that bioprosthesis

•Occasionally mistaken for native when historical information is not available.

• Careful observation yields an echogenic sewing ring and struts.

NORMAL FUNCTIONING PORCINE MITRAL PROSTHESIS

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HETEROGRAFT (XENOGRAFT)STENTLESS PORCINE VALVE

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A low-pressure glutaraldehyde fixed intact porcine valve supported by Dacron cloth

Advantage: No stents allows larger valve to be implanted

Two approved valves: Toronto SPV Freestyle Valve

Toronto SPV

STENTLESS AORTIC VALVE Stentless Aortic Valve

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SAME PATIENT - PSAX

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HETEROGRAFT (XENOGRAFT)BOVINE PERICARDIUM

Bovine (cow) pericardium fashioned into a trileaflet valve Mounted on stents and a

sewing ring

Most common brands: Carpentier-Edwards Ionescu-

Shiley (Withdrawn from United States Market)

Mitroflow 50

Carpentier Edwards – Valve Closed

AUTOGRAFTTransfer from Self to Self51

AUTOGRAFTROSS PROCEDURE

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Excision of the aortic valve Placement of the pulmonary valve annulus and

trunk into the aortic position Reimplantation of the coronary arteries.

Pulmonary side, a homograft conduit is placed between the right

ventricle and pulmonary artery

HOMOGRAFTTransfer from One Human to Another53

HOMOGRAFT (ALLOGRAFT)

Rarely used to replace a MV or TV

Aortic Homograft Harvested from human cadavers shortly

after death, (cryopreseved) May be sown into the aortic annulus without

stents. Customized by the surgeon in the operating

room at the time of implantation.

May be difficult to identify by echocardiography Aortic root may appear thicker than normal Valve failure is usually due to valvular

regurgitation 54

ADVANTAGE OF BIOPROSTHETIC VALVES May avoid anticoagulation Lower pressure gradients Central flow dynamics Failure usually occurs slowly Valve of choice in the tricuspid/pulmonic

position Stentless valve may be hemodynamically

superior to stented heterograft Increased effect orifice area Lower gradients Greater regression of ventricular

hypertrophy55

COMPLICATIONS OF BIOPROSTHETIC VALVES Calcification/degeneration Infective endocarditis

Vegetation, valve ring abscess, fistula Dehiscence (all valve replacements)

Sewing ring around prosthesis becomes unsecured to surrounding structures

Inherently stenotic Tissue preserved and fixed with within

a prolypropylene mount attached to a Dacron sewing ringLess pliable than native valve tissue. 56

COMPLICATIONS OF BIOPROSTHETIC VALVES – CONTINUED

StenosisDegeneration, thrombotic

Sewing ring may be too small relative to the flow

In young patients, what was normal as a child is now too small as an adult

Effective orifice area is significantly smaller than the area of the sewing ring Valve assembly (i.e. occluder mechanism) occupies

some of the central space57

COMPLICATIONS OF BIOPROSTHETIC VALVES - CONTINUED Deterioration of tissue valve

Occurs at an accelerated rate Younger patients Patients with end-stage renal disease on hemodialysis.

Older patients, especially in those with a risk of falling, Tissue valve may be the most appropriate choice.

Tissue valves are less durable than mechanical valves with a reported failure rate of 25% at 10 years 42% at 12 years 60% at 15 years The failure rate is higher in young patients (less than 35

years of age) and in chronic renal failure patients58

VALVED CONDUITS59

VALVED CONDUITS Used in congenital heart surgery and

ascending aortic repairs When a new passageway for blood flow

and a valve are needed

May be biologic (i.e. homograph) or artificial (i.e. Gore-Tex or Dacron) material

May incorporate either tissue or a mechanical valves

Fluid dynamics similar to those for a valve implanted in the native annulus 60

CARPENTIER-EDWARDS BIOPROSTHETIC VALVED CONDUIT

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OTHER CONDUITS

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EVALUATION OF PROSTHETIC VALVES BY TRANSTHORACIC ECHOCARDIOGRAPHY

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EVALUATION OF PROSTHETIC VALVES BY TRANSTHORACIC ECHOCARDIOGRAPHY

Confirm stability of the sewing ring Determine the specific type of prosthesis Confirm the opening and closing motion of

the occluding mechanism Can be difficult but with careful interrogation the

rapid motion of the leading edge of the disk or ball generally can be recorded.

Evaluate for gross structural abnormalities such as vegetations and thrombi

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TEE EVALUATION OF PROSTHETIC VALVES

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EVALUATION BY TEE GENERAL QUESTIONS THAT SHOULD BE ANSWERED

Is there valve dehiscence?

Is there evidence of torn/flail leaflets, ball/disc variance?

Are there mass lesions? Vegetations, thrombi, pannus

Is there valve ring abscess / pseudoaneurysm/ fistula?

How much volume/leakage volume/ pathological valvular regurgitation / paravalvular leak is present?

Is there valvular stenosis?66

TEE EVALUATION OF PROSTHETIC VALVES Helpful in patients who are too unstable to

undergo cardiac catheterizations

Surface study is inadequate for diagnosis

Regurgitation jets appear larger as compared to transthoracic

67

Non dynamic

PRESSURE RECOVERY68

PRESSURE RECOVERY Downstream pressure after

an obstruction Will be lower than the upstream

pressure before

After flow passes through orifice Pressure recovers toward its original

value Rate and magnitude: variable

depending on valvular geometry

Difference between cardiac catheterization and echocardiography pressure gradients 69

ROUTINE EVALUATION OF PROSTHETIC VALVES

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ROUTINE EVALUATION OF PROSTHETIC VALVESChamber dimension and functionValve type and movementPeak flow velocityMaximum and mean pressure

gradientsPressure half time

Generally overestimates valve area in presence of mitral prosthesis

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ROUTINE EVALUATION OF PROSTHETIC VALVES

Effective orifice area by continuity equation Pulmonary artery pressures Diastolic filling profile Color flow jet length, duration and area,

pulmonary vein (mitral regurgitation) Color flow jet or descending thoracic aorta flow

(aortic regurgitation)

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GENERAL M-MODE/ 2-D/ CARDIAC DOPPLER FINDINGS POST-PROSTHETIC VALVE SURGERY

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POST-PROSTHETIC VALVE SURGERY

7414.23 Feigenbaum

GENERAL M-MODE/ 2-D/ CARDIAC DOPPLER FINDINGS POST-PROSTHETIC VALVE SURGERYAortic Stenosis Left ventricular systolic/diastolic function

Should improve is decreased preoperatively Left ventricular hypertrophy

Should regress Peak/mean gradient

Will be reduced compared to pre-op but a residual peak and mean gradient will be present due to aortic valve replacement

If mitral regurgitation was present before surgery, May be decreased in severity post-op

Left ventricular intracavitary systolic gradients May predict a poor prognosis 75

GENERAL M-MODE/ 2-D/ CARDIAC DOPPLER FINDINGS POST-PROSTHETIC VALVE SURGERY

Aortic Regurgitation Left ventricular dimensions

Should decrease with an improvement of ventricular systolic function

Peak/mean gradients Will be increased for prosthetic heart valve compared

to native aortic valve

76

GENERAL M-MODE/ 2-D/ CARDIAC DOPPLER FINDINGS POST-PROSTHETIC VALVE SURGERY

Mitral Stenosis May be a slight increase in

Left ventricular dimensions

Left atrial dimension May decrease slightly but usually will not normalize

Left atrial appendage May be obliterated at surgery

Valve leaflets, chordae tendineae, papillary muscles May be left intact

Peak/mean gradients Will be reduced compared to pre-op

Mitral valve area Larger than pre-op

Pulmonary artery pressures May decrease 77

GENERAL M-MODE/ 2-D/ CARDIAC DOPPLER FINDINGS POST-PROSTHETIC VALVE SURGERY

Mitral Regurgitation LV dimension

Should decrease with an improvement in systolic function

LA dimension Should decrease but will not normalize

Valve leaflets, chordae tendineae, papillary muscles

May be left intact

Decreased compared to pre-op with mitral valve replacement Transmitral peak velocity, peak pressure gradient, mean

pressure gradient

Pulmonary artery pressures may decrease

78

NORMAL OR PHYSIOLOGICAL REGURGITATION

79

NORMAL OR PHYSIOLOGIC REGURGITATION

Regurgitation occurs in Virtually all types of mechanical prostheses Seating regurgitation or "closure backflow"

appears only briefly Due to retrograde volume displacement as the valve

leaflets close.

Divided into two types Closure backflow Leakage

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COMPLICATIONS81

AORTIC ROOT ABSCESS

Echo-free space is seen posterior to the aortic root and associated perivalvular regurgitation.

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14.27 Feigenbaum

14.27b Feigenbaum

PERIVALVULAR LEAK

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Example of stentless aortic prosthetic valve Mild degree of

perivalvular regurgitation is seen.

14.28a Feigenbaum

OBSTRUCTION

The most common cause of prosthesis obstruction is the presence of a thrombus.

84

THROMBUS ECHOCARDIOGRAM

Large thrombus Left atrial aspect of

the mitral prosthesis

8514.37 Feigenbaum

VEGETATION Prosthetic valve

Most common site for attachment of a vegetation is the sewing ring.

Large vegetation can be seen in the left atrium Attached to the sewing

ring of a St. Jude mitral prosthesis.

86

14.46 Feigenbaum

RING ABSCESS

87

14.51b Feigenbaum

14.51c Feigenbaum

DEHISCENCE

Dehiscence of porcine mitral prosthesis Excessive motion of the prosthetic valve was evident.

Abnormally high peak flow velocity (2.8 cm/sec) Increased gradient

(14 mm Hg) 88

14.52 Feigenbaum

VALVED CONDUITS89

VALVED CONDUITS Part of repair of some forms of

complex congenital heart disease

Not all conduits contain valves and those that do may use either bioprosthetics or mechanical prostheses.

Conduit itself often has a characteristic echocardiographic appearance due to the conduit material and the ribbed design 90

REPAIR

Adult patients with aortic valve pathology are seldom candidates for valve repair.

Valve replacement is usually necessary for significant aortic stenosis or regurgitation.

91

MITRAL VALVE REPAIR92

MITRAL VALVE REPAIR

Repairing rather than replacing Several advantages and is being performed with

increasing frequency.

Mitral and tricuspid valve pathologies should be considered for valve repair Operative mortality associated with repair of these

valves is lower than that associated with their replacement.

93

MITRAL VALVE REPAIR

Selection of repair vs. replace is dependent uponEtiology, morphology and severity as

well as the status of the left ventricle.

Replacement for :severe scarring and deformation by a disease process such as advanced rheumatic heart disease advanced lupus another inflammatory process

94

MITRAL VALVE REPAIR SUCCESS RATE IN PATIENTS WITH MYXOMATOUS DEGENERATION AND MITRAL VALVE PROLAPSE

Posterior leaflet prolapse Carries a greater likelihood of successful

repair Than anterior or bi-leaflet prolapse

95

http://www.escardio.org/communities/EAE/CasePortal/Pages/Case159.aspx

96

SOME DEGREE OF REGURGITATION MAY REMAIN AFTER REPAIR

97

Stable mitral ring in mitral position Well preserved leaflet

excursion

14.59 Feigenbaum

14.60a Feigenbaum

FUTURE OF VALVULAR REPLACEMENT?

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99

SAFETY AND EFFICACY STUDY OF THE MEDTRONIC COREVALVE® SYSTEM IN THE TREATMENT OF SYMPTOMATIC SEVERE AORTIC STENOSIS IN HIGH RISK AND VERY HIGH RISK SUBJECTS WHO NEED AORTIC VALVE REPLACEMENT

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Clinical Trial for transcatheter aortic valve implantation (TAVI)

>1,300 patients Subjects have one of two options:

1. Open heart surgical aortic valve replacement2. Transcatheter aortic valve implantation (only

available through the clinical trial)

CLINICAL TRIAL FOR TRANSCATHETER AORTIC VALVE IMPLANTATION (TAVI)

101

45 Sites Across the US. Trial Locations in Michigan

Detroit Medical Center Spectrum Health Hospitals University of Michigan Health Systems

COREVALVES

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Inclusion criteriaPredicted risk of operative mortality ≥15%Senile degenerative aortic valve stenosis

Mean > 40 mmHg/left velocity >4.0 m/sec AND

Initial AVA ≤0.8 cm2 (or AVA index ≤0.5 cm2/m2)

Symptomatic; NYHC Functional Class II or greaterSubject informed of the nature of the trial, agrees and has provided written informed consent as approved by IRB of the respective clinical siteSubject and treating physician agree that the subject will return for all post-procedure follow-up visits

COREVALVES

103

Exclusion CriteriaEvidence of an acute myocardial infarction ≤ 30 days before the index procedure.Any percutaneous coronary or peripheral interventional procedure performed within 30 days prior to the index procedure.Blood dyscrasias as defined: leukopenia (WBC < 1000mm3), thrombocytopenia (platelet count <50,000 cells/mm3), history of bleeding diathesis or coagulopathy, or hypercoagulable states.Untreated clinically significant coronary artery disease requiring revascularization.Cardiogenic shock manifested by low cardiac output, vasopressor dependence, or mechanical hemodynamic support.Need for emergency surgery for any reason.Severe ventricular dysfunction with left ventricular ejection fraction (LVEF) < 20% as measured by resting echocardiogram.Recent (within 6 months) cerebrovascular accident (CVA) or transient ischemic attack (TIA).

COREVALVES

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Exclusion CriteriaEnd stage renal disease requiring chronic dialysis or creatinine clearance < 20 cc/min.Active Gastrointestinal (GI) bleeding within the past 3 months.A known hypersensitivity or contraindication to any of the following which cannot be adequately pre-medicated:

aspirin Heparin (HIT/HITTS) and bivalirudin (only for Extreme Risk

patients) nitinol (titanium or nickel alloy) ticlopidine and clopidogrel contrast media

COREVALVES

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Exclusion CriteriaOngoing sepsis, including active endocarditis.Subject refuses a blood transfusion.Life expectancy < 12 months due to associated non-cardiac co-morbid conditions.Other medical, social, or psychological conditions that in the opinion of an Investigator precludes the subject from appropriate consent.Severe dementia (resulting in either inability to provide informed consent for the trial/procedure, prevents independent lifestyle outside of a chronic care facility, or will fundamentally complicate rehabilitation from the procedure or compliance with follow-up visits).Currently participating in an investigational drug or another device trial.Symptomatic carotid or vertebral artery disease.Additional Exclusion for High Risk Surgical only: Subject has been offered surgical aortic valve replacement but declined.Anatomical

COREVALVES (TAVI)

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Exclusion CriteriaNative aortic annulus size < 20 mm or > 29 mm per the baseline diagnostic imaging.Pre-existing prosthetic heart valve any position.Mixed aortic valve disease (aortic stenosis and aortic regurgitation with predominant aortic regurgitation (3-4+).Moderate to severe (3-4+) or severe (4+) mitral or severe (4+) tricuspid regurgitation.Moderate to severe mitral stenosis.Hypertrophic obstructive cardiomyopathy.Echocardiographic evidence of intracardiac mass, thrombus or vegetation.Severe basal septal hypertrophy with an outflow gradient.Aortic root angulation (angle between plane of aortic valve annulus and horizontal plane/vertebrae) > 70° (for femoral and left subclavian/axillary access) and > 30° (for right subclavian/axillary access).

COREVALVES

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Ascending aorta diameter > 43 mm unless the aortic annulus is 20-23 mm in which case the ascending aorta diameter > 40 mm.

Congenital bicuspid or unicuspid valve verified by echocardiography.

Sinus of valsalva anatomy that would prevent adequate coronary perfusion.

Vascular Transarterial access not able to accommodate an

18Fr sheath.

SOURCES CoreValve U.S. Pivotal Trial. Medtronic. [Online] 2010.

[Cited: February 20, 2012.] http://www.medtronic.com/corevalve/ous/system.htm.

Feigenbaum H, Armstrong W. (2004). Echocardiography. (6th Edition). Indianapolis. Lippincott Williams & Wilkins.

Goldstein S., Harry M., Carney D., Dempsey A., Ehler D., Geiser E., Gillam L., Kraft C., Rigling R., McCallister B., Sisk E., Waggoner A., Witt S., Gresser C.. (2005). Outline of Sonographer Core Curriculum in Echocardiography.

Kardon, Eric. Prosthetic Heart Valves. Medscape Reference. [Online] February 08, 2010. [Cited: February 20, 2012.] http://emedicine.medscape.com/article/780702-overview.

Otto C. (2004). Textbook of Clinical Echocardiography. (3rd Edition). Elsevier & Saunders.

Reynolds T. (2000). The Echocardiographer's Pocket Reference. (2nd Edition). Arizona. Arizona Heart Institute.

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