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prosthetic heart valves -Dr. Raajit Chanana
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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