VALVE REPLACEMENT

RAHUL ARORA

JR III

VALVE REPLACEMENTOUTLINE

INTRODUCTION TYPES OF VALVE PROSTHESIS SELECTION OF AN ARTIFICIAL VALVE INDICATIONS OF VALVE REPLACEMENT TECHNIQUE FOR VALVE REPLACEMENT SURGERY RISKS OF SURGERY COMPLICATIONS PROPHYLAXIS AND FOLLOW UP RECENT ADVANCEMENTS IN VALVE REPLACEMENT

INTRODUCTIONHISTORY 1952 – First mechanical heart valve was

implanted. 1962 – First successful biological valve was

implanted.

EPIDEMIOLOGY 80,000 undergo cardiac valve replacement in US

annually. Approx.265,000 prosthetic valves implanted

worldwide each year. In India, 10,000 cardiac valve replacement are

being carried out yearly (estimate 2010)

TYPES OF ARTIFICIAL VALVE

MECHANICALinert synthetic materialdurable

BIOPROSTHETICAnimal tissue

Choice of prosthesis depends on anticipated longevity of the patient and his/her ability to tolerate anticoagulation.

.

MECHANICAL VALVESStarr-Edwards Silastic ball valve

Chitra TTK tilting disc valve (Indian)

St. Jude Medical bileaflet valve

St. Jude bileaflet valves Most commonly implanted mechanical valves Low bulk and flat profile Superior hemodynamics have a greater effective opening area lower transvalvular pressure gradient at any outer

diameter and cardiac output Starr-Edwards valve Bulky Not suitable for the mitral position Induces hemolysis, more if perivalvular leak

develops. As size decreases, valve becomes stenoticTHROMBOGENICITY: tilting disc > caged ball > bileaflet

NEXT GENERATION OF MECHANICAL

VALVE: TRILEAFLET VALVE

More physiological

Better hemodynamics ‘central blood flow’

Reduced thrombosis risk

BIOPROSTHETIC VALVE TYPES DEPENDING ON

SOURCE XENOGRAFT HOMO/ALLOGRAFT AUTOGRAFT

TYPES DEPENDING ON PRESENCE OF STRUTS STENTED STENTLESS

lower post-operative valvular gradient, greater post-operative effective orifice

area index (EOAI), earlier regression of LVH. Stentless heterografts have the

disadvantages that their implantation is more complex

STENTLESS

STENTED

DIFFERENCES BETWEEN MECHANICAL AND BIOPROSTHETIC VALVE

MECHANICAL BIOPROSTHETIC

LIFESPAN 30 YEARS OR MORE 10-15 YEARS

THROMBOGENICITY MORE LESS

NOISE MORE NEGLIGIBLE

PATIENT-PROSTHESIS MISMATCH

MORE LESS

VALVE DETERIORATION DURABLE HIGHLY SUSCEPTIBLE

HEMODYNAMICS IMPROVING CLOSE TO NATURAL

ANTICOAGULATION LIFELONG 3 MONTHS

RISK OF REOPERATION LESS MORE

SELECTION OF AN ARTIFICIAL VALVE RISK BENEFIT RATIO

MULTIFACTORIAL Age Site of involvement Size of LV cavity Special situation(Pregnancy, Associated

cardiac abnormalities) Patient’s preference(Anticoagulation, regular

follow up)

FACTORS Age

>65 years : bioprosthesis <65 years : mechanical

Anticoagulation Ready : mechanical No / contraindication : bioprosthesis

Prosthesis mechanical at other site : mechanical Reoperation / Infective endocarditis : bioprosthesis

o Special women of child bearing age : bioprosthesis Risk factors : atrial fibrillation, hypercoagulabilty :

mechanical Small aortic annulus : stentless bioprosthetic Site of valve

aortic : mechanical (survival benefit in some studies) Tricuspid : bioprosthetic (high incidence of thrombus formation)

DESIGN CONSIDERATIONS Has to mimic the blood flow properties of a normal

heart valve, called “central flow” keeps work done by the heart to a minimum.

Not allow stagnation / pooling of blood to decrease risk of clots.

to reduce mechanical causes of hemolysis. It should be quiet. Minimum ‘patient–prosthesis mismatch’.

MAJOR CRITERIA FOR AORTIC VALVE SELECTIONClass I mechanical prosthesis is recommended for patients with a

mechanical valve in the mitral or tricuspid position. (C)

bioprosthesis is recommended for patients of any age who will not take warfarin or have major medical contraindications to warfarin therapy. (C)

Class IIa mechanical prosthesis for patients under 65 years of age who do

not have a contraindication to anticoagulation.

bioprosthesis is reasonable for patients aged 65 years or older without risk factors for thromboembolism. (C)

Aortic valve re-replacement with a homograft is reasonable for patients with active prosthetic valve endocarditis. (C)

Class IIb A bioprosthesis might be considered for woman of childbearing

age(C)

MAJOR CRITERIA FOR MITRAL VALVE SELECTIONClass I bioprosthesis is indicated for those patients who

will not take warfarin, is incapable of taking

warfarin, or has a clear contraindication to warfarin therapy. (C)

Class IIa mechanical prosthesis is reasonable for patients

under 65 years of age with long-standing atrial

fibrillation. (C)

bioprosthesis is reasonable for patients 65 years of age or older. (C)

bioprosthesis is reasonable for patients under 65 years of age in sinus rhythm after proper counselling.(C)

INDICATIONS OF BIOPROSTHETIC VALVE

patients with contraindications for anticoagulant therapy

patients who are noncompliant with permanent anticoagulant treatment, who are unwilling to take anticoagulants on a regular basis, or cannot be monitored;

patients over the age of 65 years because of greater risk of hemorrhage while taking anticoagulants;

patients with a small aortic annulus in whom an unstented (free) bioprosthetic graft may provide superior hemodynamics; and

younger women wishing to bear children, who require AVR.

INDICATIONS FOR VALVE REPLACEMENT

MITRAL VALVE REPLACEMENT MITRAL STENOSIS

Class I symptomatic (NYHA functional class III–IV) moderate or severe MS percutaneous mitral balloon valvotomy is unavailable, percutaneous mitral balloon valvotomy is contraindicated

because of left atrial thrombus despite anticoagulation or because concomitant moderate to severe MR is present (C), or

Valve morphology is not favorable for valvotomy (B) extensive commissural calcification, severe fibrosis, and subvalvular fusion valve severely distorted by previous transcatheter or operative

manipulation, or preservation of the chordal attachments to optimize LV functional recovery.

Class IIa severe pulmonary hypertension (PASP > 60) with NYHA

functional class I–II symptoms, and MV Area< 1 cm2 who are not considered candidates for percutaneous mitral balloon valvotomy or surgical MV repair. (C)

MITRAL VALVE REPLACEMENT MITRAL REGURGITATION

Class I symptomatic patient with acute severe MR.(B)

chronic severe MR and NYHA functional class II, III, or IV symptoms in the absence of severe LV dysfunction (severe LV dysfunction is defined as EF < 30% and/or ESD > 55mm). (B)

asymptomatic patients with chronic severe MR and mild to

moderate LV dysfunction, EF between 30% to 60%, and/or

ESD ≥ 40 mm. (B)

Class IIa asymptomatic patients with chronic severe MR, preserved LV

function, and new onset of atrial fibrillation or pulmonary hypertension (PASP > 50 mm Hg at rest or > 60 mm Hg with exercise). (C)

chronic severe MR due to a primary abnormality of the mitral apparatus and NYHA functional class III-IV symptoms and severe LV dysfunction (EF < 30% and/or ESD > 55 mm) in whom MV repair is highly likely. (C)

AORTIC VALVE REPLACEMENT AORTIC REGURGITATION

Class I symptomatic patients with severe AR irrespective of LV

systolic function.(B) asymptomatic patients with chronic severe AR and LV systolic

dysfunction (ejection fraction 0.50 or less) at rest.(B) chronic severe AR while undergoing CABG or surgery on the

aorta or other heart valves.(C)

Class IIa asymptomatic patients with severe AR with normal LV systolic

function (EF greater than 0.50) but with severe LV dilatation (EDD greater than 75 mm or ESD greater than 55 mm).(B)

AORTIC VALVE REPLACEMENT AORTIC REGURGITATION

Class IIb Moderate AR while undergoing surgery on the ascending

aorta or CABG. (C) asymptomatic patients with severe AR and normal LV

systolic function at rest (EF greater than 0.50) when the degree of LV dilatation exceeds an EDD of 70 mm or ESD of 50 mm, when there is evidence of progressive LV dilatation, declining exercise tolerance, or abnormal hemodynamic responses to exercise.(C)

Class III not indicated for asymptomatic patients with normal LV

systolic function at rest when the degree of dilatation is not moderate or severe.(EDD<70mm or ESD<50mm)(B)

AORTIC VALVE REPLACEMENTAORTIC STENOSIS

Class ISevere AS (AVA < 0.6 cm2, mean gradient>60 mm Hg, and jet

velocity>5.0 m/s ) o symptomatic.(B)o undergoing CABG or surgery on the aorta or other heart valves.

(C)o LV systolic dysfunction (EF<50%). (C)

Class IIa moderate AS undergoing CABG or surgery on the aorta or other

heart valves (B)

Class IIb severe asymptomatic AS with abnormal response to exercise or a

high likelihood of rapid progression (age, calcification, and CAD) or if surgery might be delayed at the time of symptom onset.(C)

severe asymptomatic AS when the patient’s expected operative mortality is 1.0% or less.(C)

Undergoing CABG who have mild AS with when there is evidence, moderate to severe valve calcification, that may progress rapidly. (C )

TRICUSPID VALVE REPLACEMENT

Class IIa Severe primary TR when symptomatic. (C)

Severe TR secondary to diseased/abnormal tricuspid valve leaflets not amenable to annuloplasty or repair. (C)

Severe TS (mean diastolic pressure gradients > 4 mmHg & tricuspid orifice areas <1.5–2 cm2 ) along with MVR.

It is resonable to do TVR 6 to 9 months after valve excision and control of the infection in case of tricuspid valve endocarditis.

PULMONARY VALVE REPLACEMENT severe PR caused by surgical correction of tetralogy of

Fallot, is required only occasionally because of intractable right heart failure.

Under such circumstances, valve replacement may be carried out, preferably with a porcine bioprosthesis or a pulmonary allograft.

There is growing experience with catheter-based approaches to pulmonic valve replacement in native pulmonic valve disease and in PR following surgical correction of congenital heart defects.

SURGERY FOR NATIVE VALVE ENDOCARDITIS

Class I Valve dysfunction resulting in heart failure. (B)

AR or MR with hemodynamic evidence of elevated LVED or left atrial pressures. (B)

Persistent infection after 7 to 10 days of adequate antibioic therapy; infection due to fungal or other highly resistant organisms. (B)

Complicated by heart block, annular or aortic abscess, or destructive penetrating lesions (e.g., ruptured sinus of Valsalva to right atrium, right ventricle, or left atrium fistula; mitral leaflet perforation with aortic valve endocarditis; or infection in annulus fibrosa). (B)

SURGERY FOR PROSTHETIC VALVE ENDOCARDITIS

Class I heart failure. (B)

Valve dehiscence evidenced by cine fluoroscopy or

echocardiography. (B)

evidence of increasing obstruction or worsening

regurgitation. (C)

Persistent infection after 7-10 days of adequate antibiotic therapy

complications (e.g., abscess formation). (C)

Class IIa Emergency operation in patients with a thrombosed left-

sided prosthetic valve and NYHA functional class III–IV

symptoms or have a large clot burden>5cm resulting in recuurent emboli. (C)

TECHNIQUE FOR VALVE REPLACEMENT SURGERY

At present, majority of valve replacement surgeries are open heart surgery using a heart-lung machine.

This machine will keep oxygen-rich blood flowing through the body while the heart is stopped and cooled.

Next, a cut is made into the heart or aorta, depending on which valve is being repaired or replaced.

Once the surgeon has finished the repair or replacement, the heart is then started again, and patient is disconnected from the heart-lung machine.

MINIMALLY INVASIVE VALVE SURGERY a technique that uses smaller incisions to repair or replace

heart valves. less pain and reduces the length of the hospital stay and the

recovery time. It cannot be done in patients

severe valve damage more than one valve repaired or replaced Coronary artery disease obese

Could be done using a robot.

TRANSCATHETER AORTIC VALVE IMPLANTATIONIndications

•Severe symptomatic aortic stenosis•Estimated operative mortality for conventional surgery > 20%•Severe ascending aortic calcification that prevents aortic cannulation•Severe radiation damage

FACTORS FOR PERIOPERATIVE RISKPerioperative mortality rate depends on advanced age comorbidity (e.g., pulmonary or renal disease,

the need for nonvalvular cardiovascular surgery, diabetes mellitus)

preoperative functional disability and Pulmonary Arterial hypertension.

Overall perioperative mortality is 5% and reducing.The overall 10-year survival of surgical survivors is

∼70%. Reoperation carries double the risk and

perioperative mortality.

LATE COMPLICATIONS OF VALVE REPLACEMENT Thromboemboli, Bleeding due to anticoagulants, Mechanical valve thrombosis, Pannus ingrowth, Paravalvular leak, Hemolysis, Structural deterioration, Infective endocarditis, and Prosthesis - patient mismatch (functional

prosthetic valve stenosis that occurs when the prosthesis is too small relative to the patient's anatomy).

FOLLOW UP AND SPECIAL PRECAUTIONS Antibiotic prophylaxis prior to dental procedures

that involve manipulation of gingival tissue or the periapical region of teeth or perforation of the oral mucosa is indicated for patients after valve replacement.

Prosthetic valve and ventricular function should be assessed with transthoracic echocardiography 3 months after surgery and physical examination, ECG, chest X-ray, blood urea nitrogen/creatinine, electrolytes, INR, a baseline complete blood count, reticulocyte count, and serum lactate dehydrogenase (LDH) test obtained to serve as a baseline set of values should the question of hemolysis arise in the future.

Risk factors include atrial fibrillation, previous thromboembolism,LV dysfunction, older-generation thrombotic valve, mechanical tricuspid valve or more than 1 mechanical valve and hypercoagulable condition.

TAKE HOME MESSAGEResults of valve replacement surgery are dependent on

the patient's myocardial function and general medical condition at the time of operation;

the technical abilities of the operative team and the quality of the postoperative care; and

the durability, hemodynamic characteristics, and thrombogenicity of the prosthesis.

Patient preference must be factored into any decision regarding the type of valve replacement.

Decision to proceed with valve replacement should be finalized only when valve repair is either not appropriate or not feasible.

Bioprosthesis remain the preferred valve choice for patients older than 65 years, pregnant, as well as for others who refuse to take anticoagulation or for whom anticoagulation may be contraindicated.

THANK YOU