PROSTHETIC HEART VALVES

- Dr. Raajit Chanana

Mechanical Bileaflet eg St Jude Medical, Carbomedics Tilting disc/Single disc eg Medtronic Hall Ball cage eg Star Edwards

Bioprosthesis /Tissue   Stented Porcine –Medtronic Hancock ,

Carpentier- Edwards   Stentless Porcine -St. Jude Medical Toronto

SPV , Medtronic Mosaic  Pericardial  bovine   Carpentier-Edwards Perimount

    

Types

Star Edwards caged ball valve

St Jude bileaflet valve

Carpentier edwards pericardial valve

Cadavers –within 24 hours Subcoronary position or the valve and a

portion of attached aorta are implanted as a root replacement with reimplantation of coronary arteries into the graft.

Advantages superior hemodynamic, low thrombogenicity,

avoidance of early endocarditis Disadvantages Higher SVD, prone to calcification, prosthetic

AR

Homograft/ Allograft Aortic valves

Pts own pulmonary valve and adjacent main pulm artery-removed-replace diseased aortic valve with implantation of the coronary arteries into the graft

Human pulm or aortic homograft inserted into pulm position

Pulmonary autograft/ Ross procedure

Advantage endocarditis risk low ,durable Disadvantage pulmon homograft stenosis (postop

inflammatory reaction) should not be performed in bicuspid aortic

vavle and dilated aortic roots Choice-children , adults of life

expectancy>20yrs and women who wish to become pregnant

Bileaflet valve are the most commonly implanted mechanical valve

Low bulk Flat profile Superior hemodynamic

Heart sounds The closure of the mechanical valve

accentuates the normal heart sound and the intensity of the sound is proportional to the mass of the closure device in the prosthetic valve

Lack of accentuation of the opening or closure sound of the valve suggests an abnormality, such as the presence of thrombus, vegetation or pannus and should be investigated.

Normal physiology

Opening is always less intense than closure If there are 2 prosthetic valve all

mechanical heart sounds are loud Opening and closing are high frequency

sounds and should be differentiated from S3 and S4

Complete absence of an opening sound in a patient with a disk or bileaflet is not unusual such as heavy built or hyperinflated lung

Prosthetic aortic valves

Systolic ejection murmer-prosthetic valve effective area is less than that of native valve, thus there is a mild inherent aortic stenosis

Absenc of SEM low cardiac output hyperinflated lungs Abnormality of prosthetic valve

Diastolic murmur-perivalvular leak or valvular regurgitation, thrombus

Normal physiology

Mitral valve Usually do not produce murmurs. Occasionally low freq rumble in mid diastole in

thin persons and due to smaller effective size.A holosystolic murmur-malfunction of

valve or perivalvular leak.

Any murmur with a mechanical tricuspid valve should prompt an investigation for etiology

Type of valve

AORTIC PROSTHESIS

MITRAL PROSTHESIS

Normal findings

Abnormal findings

Normal findings

Abnormal findings

Bileaflet (St. Jude medical)

cc S1OC

Aortic diastolic murmurDecreased intensity of closing click

High frequency holosystolic murmurDecreased intensity of closing click

p2SEM CCDM

OC

s2

Mechanical valve Warfarin should begin 2 days after

operation Aortic valve –target INR 2-3 if no risk factors If higher risk for thrombosis eg AF,previous

thromboembolism target INR 2.5-3.5 For all valves in the mitral position target

INR 2.5-3.5 Low dose aspirin 75-100mg

Anticoagulants in prosthetic valves

Bioprosthetic valve During first 3 post op months while the

sewing ring becomes endothelized there is risk of thrombosis so warfarin is given

If no risk factors present then warfarin not given

If risk factors –previous embolism,thrombus in the left atrium at operation, remain in AF postoperatively ,need for anticoagulaion persists

Aortic valve replacementClass 1 Mechanical prosthesis in patients with a

mechanical valve in the mitral or tricuspid position

Bioprosthesis in patients of any age who will not take warfarin or who have major medical contraindications to warfarin therapy

Crieria for selection of replacement valves for individuals

Class 2a Patient consideration is a reasonable

consideration in the selection of valve prosthesis. Mechanical prosthesis is reasonable for AVR in pts <65yrs who do not have contraindication to anticoagulation

Cont…. A bioprosthesis is reasonable for AVR in

patients <65yr who elect to receive this valve for lifestyle considerations after detiled discussions of the risks of anticoagulantversus the likelyhood that a second AVR may be neede in the future

Cont… Bioprosthesis is reasonable for patients

>=65yr without risk factors for thromboembolism

Homograft is reasonable for patients undergoing repeat AVR with active prosthetic valve endocarditis

Class 2b Bioprosthesis might be considered for a

woman of child bearing age

Mitral valve replacementClass1 Bioprosthesis in patients who will not take

warfarin, is incapable of taking warfarin, or has clear contraindication to warfarin therapy

Class 2a Mechanical prosthesis reasonable for

patients <65yr with longstanding AF

Bioprosthesis is reasonable in patients >=65yr

Bioprosthesis reasonable for patients <65yrin sinus rhythym who elect to receive this valve for life style considerations after detailed discussions of the risks of anticoagulation versus the likelyhood that a second MVR replacement may be necessary in future.

Prosthetic endocarditis Prosthetic dehiscence Prosthetic dysfunction  - Obstruction: usually thrombotic Regurgitation   Hemolysis    Structural failure Thromboemboli Hemorrhage with anticoagulant therapy Valve prosthesis–patient mismatch Prosthetic replacement Late mortality, including sudden, unexplained death

Complictions of PHV

Mechanical Bioprosthesis Durability more Thrombus +++ + Infection +++ + Dehiscence + +++ Stenosis + ++ Degeneration + +++

Blood pressure wide pulse pressure hypotension Pulses Absent limb pulses Bifid carotid pulse Slow rising low amplitude carotid pulse Elevated jugular venous pulse

Physical findings that prompt consideration of echocardiography

Palpation Thrill Bifid apical impulse New right or left ventricular heaves

Auscultation Decreased intensity of valve closure sound Loss of previous heard opening sounds New gallops Systolic murmur with mitral prosthesis Any diastolic murmur

General Prolonged fever without obvious source Embolic phenomenon

Indications of echocaardiography in patients with PHV First outpatient postop visit 3-4 week after

hospital discharge for baseline assessment of valve function and left ventricular remodelling

New regurgitant murmur Development of new or changing

cardiovascular symptoms Lack of improvement or deterioration of

functional capacity or cardiovascular symptoms after valve replacement

Every 6 month in asymptomatic patients with bioprosthetic valve degeneration and >=mild regurgitation

Patients with suspected valve obstruction caused by thrombus or pannus growth

Patients with suspected PVE

All patients with PHV need appropriate antibiotics for prophylaxis against infective endocarditis

Patients with rheumatic heart disease continue to need antibiotics as prophylaxis against the recurrence of rheumatic carditis

Adequate antithrombotic therapy is needed for appropriate patients

Management

Several syndromes are peculiar to the postoperative period.

• Postperfusion syndrome 3rd or 4th postoperative week. fever, splenomegaly, and atypical lymphocytes; benign and self-limited.

• Postpericardiotomy syndrome fever and pleuropericarditis. 2nd and 3rd postoperative week, but can appear as late as 1 year after surgery self-limited, most patients benefit from taking antiinflammatory drugs

• Even though the pericardium is left open at the end of surgery, cardiac tamponade has been known to occur during the first 6 weeks and needs to be relieved.

Thank you