PROSTHETIC HEART VALVE : Types, Selection, and Functional assessment Dr SHAJUDEEN 2nd Year DM Resident HISTORY OF PROSTHETIC HEART VALVE First Mechanical valve was designed by Charles Hufnagel in 1954 ( Implanted in descending thoracic aorta for AR) Plexiglass (Methyl Methacrylate)cage &
Silicone-coated nylon poppet Dwight Harken perfomed the first aortic valve replacement in 1960 Nina Braunwald implanted the first Ball and cage valve in Mitral position in 1960 Homograft was first developed by Donald Ross Porcine valve was first implanted by Binet et al. Alian Carpenter discovered Gluteraldehyde Fixation The name Bioprosthetic valve was coined by Carpentier.
David implanted the first stentless porcine bioprosthesis in 1988 Ross & Boyes performed the first successful allograft replacement from cadaver in 1962 ADVANCEMENT IN PHV TECHNOLOGY Ball and cage Ball and Disc Porcine valve Pericardial valve
Titling Disc Stentless valves (1988) Bileaflet New Generation valve ( Trileaflet valve) under Trial
Trans catheter Prosthesi Changes in Valve Processing Technology Formaldehyde fixation Anticalcification treatment( Alpha oleic acid (AOA) & Polysorbate 80) Gluteraldehyde fixation under Gluteraldehyde fixation Normal pressure advantages Cross links Collgen fibers
Reduces Tissue antigenicity Enzymatic degradation Cell viability Zero pressure fixation AOA binds to the bioprosthetic tissue & inhibit calcium flux
Problem with the High Pressure fixation Early matrix fragmentation & Premature valve degeneration Prosthetic Heart valve PROSTHETIC HEART VALVE CLASSIFICATION MECHANICAL PROSTHETIC HEART VALVES BALL &CAGE TILTING DISC
BILEAFLET VALVES BIOPROSTHETIC HEART VALVES AUTO GRAFT HOMOGRAFT HETERO GRAFT STENTED : PORCINE or PERICARDIAL STENTLESS : PORCINE Homograft : From Human cadaver Heterograft : From Porcine or Bovine
PHV valves: Advantages and Disadvantages Mechanical heart valve Bioprosthetic heart valves Advantage Durability high Advantage o Prolonged anticoagulation not needed
Disadvantages o Limited durability. o Structural valve degeneration Disadvantage Thrombosis & Thromboembolism risks high so life long anticoagulation Mechanical PHV Basic structure
TTKCHITRA The ball is a silicone rubber polymer, impregnated with barium sulfate for radiopacity, which oscillates in a cage of
Mechanical valve types merits and demerits Ball and Cage Advantage of the design Advantages Occluder travel completely out of orifice reducing the possibility of thrombus or pannus growing from the sewing ring to interfere with the Valve Mechanism
Continous changing point of contact of the ball reduces the wear and tear in any one area Disadvantage Central flow Obstruction Collisions with the occluder ball causes damage to blood cells.
Bulky cage design so not suitable for if small LV cavity. or small aortic annulus. Thrombogenic risk is slightly higher ie 4% to 6% per year TILTING DISC : KEY FEATURES Tilting disc Advantage & Disadvantages Advantage over Ball & Cage
Low profile Disadvantage Thrombus and Pannus interfering with the motion of disc Central blood flow. Careful orientation of disc needed Decrease turbulence during implantation Reduce shear stress.
Thrombotic risk is reduced TTK-CHITRA:ADVANTAGES ONLY INDIAN-MADE HEART VALVE Complete structural integrity Silent operation Rotatable within the sewing ring to assure its freedom to rotate if repositioning needed. Low profile, most price-friendly
Low thromboembolism even if poor anticoagulant compliance Bileaflet valves advantages over single disc Carbon leaflets and flange exhibit high strength and excellent biocompatibility Superior hemodynamics Lower transvalvular pressure gradient at any outer diameter and cardiac
Largest opening angle output than caged ball or tilting disc Low turbulence. valves Low bulk and flat profile Easier insertion
Thrombogenicity in the mitral position may be less than that associated with other prosthetic valves Bioprosthetic valves : Key features Pericardial valve: Made from Bovine pericardium mainly but from Porcine or Equine also. Pericardial valve are invariably stented
Increased durability due to increased amount of collagen More symmetrical function of leaflet so better hemodynamics Homograft (Allograft) Aortic Valves Harvested from cadavers usually within 24 hours of donor death Insertion: usually in the Aortic position without a prosthetic stent and implanted in the subcoronary position with valve alone or the valve and a portion of aorta are implanted as a root
replacement, with reimplantation of the coronary arteries into the graft Pulmonary Autografts Ross procedure : Patient's own pulmonary valve and adjacent main pulmonary artery are removed and used to replace the diseased aortic valve with reimplantation of the coronary arteries in to the graft. The autograft is non thrombogenic and no anticoagulation is needed
Risk of Endocarditis is very low. NEXT GENERATION VALVE The next generation of
mechanical valves is the trileaflet which mimics natural function and
hemodynamics more closely heart has valve
improved and the potential for greatly reduced SELECTION OF PROSTHETIC HEART VALVE
Factors to be considered while selecting a prosthetic heart valve Age of the patient Comorbid condition ( cardiac and non cardiac) Expected lifespan of the patient Long term outcome with the prosthetic heart
valves Patient wishes Skill of the surgeon Women of child bearing ages For valve replacement for IE: Homograft preffered For Narrow
aortic root if root enlargement/replacement not possible choice is Bileaflet valves.
ACC Guidelines for selection of PHV PHV Selection in Pregnancy Evaluation of prosthetic valves Evaluation of prosthetic valves CLINICAL INFORMATION &CLINICAL EXAMINATION IMAGING OF THE VALVES CXR
2D echocardiography TEE 3D echo CineFluoro CT Cardiac catheterisation CLINICAL INFORMATION Clinical data : Reason for the study & the patients symptoms Type & size of replaced valve.
Date of surgery. Patients height, weight, and BSA should be recorded to assess whether prosthesis-patient mismatch (PPM) is present BP & HR HR particularly important in mitral and tricuspid evaluations because the mean gradient is dependent on the diastolic filling period X-Ray in PHV : Identification of Valves
Carina AV MV Apex Chest X ray AP View The Aortic valve - intersection of these two lines. The Mitral valve -
lower left quadrant (patients left). The Tricuspid valve - lower right corner (the patient's right) The Pulmonic valve- upper left corner (the patient's left).
Determination of site of valve by assesing the direction of flow If the direction of flow is from Inferior to superior likely aortic valve. Superior to inferior- likely a mitral valve. X-ray detection of complication: Strut fracture in Bjork shiley Bjork Shiley PHV Normal structure
Cinefluoroscopy Structural integrity Motion of the disc or poppet Excessive tilt ("rocking") of the base ring - partial dehiscence of the valve. A rocking motion of greater than 150 of sewing-ring excursion is abnormal Aortic valve prosthesis - RAO caudal - LAO cranial Mitral valve prosthesis - RAO cranial . valuation of prosthetic valves-Cinefluoroscopy
Concept of Opening and closing angle: Medronic hall St Jude Medical standard &, Reagent, On X CarboMedics standard Opening angle 750
850 780 St. Jude medical bileaflet valve ECHO ASSESSMENT OF PROSTHETIC HEART VALVES Flow dynamics of different types of PHV Ball & Cage
Tilting disk Bileaflet Echo in PHV Evaluation : General consideration Compared with a native valve the prosthetic valves are inherently stenotic. The type and size of prosthesis determines what is considered normal function for that valve. So
gradients, EOA, and degree of physiologic
regurgitation will vary based on valve type, manufacturer, and valve size. Echo in PHV Evaluation : General consideration Always use multiple views during echo evaluation of PHV.
For Stented valves-ultrasound beam aligned parallel to flow to avoid the shadowing effects of the stents and sewing ring Echo in PHV Evaluation : General consideration Complete evaluation requires TTE and TEE. TEE is ideal for visualizing the LA, Pul. Veins & LA side of the prosthesis Echo Artifacts due to PHV: Acoustic shadowing Reverberation
Refraction & Mirror artifacts. Doppler assessment:General consideration High sweep speeds (100 mm/s) increases the accuracy of Doppler measurements. Doppler Quantitative Parameters should be averaged from 1 to 3 cycles in sinus rhythm and 5 to 15 cycles in atrial fibrillation to increase accuracy TEE Views
The most useful views include the mid esophageal 4-chamber, 2-chamber, & 3chamber views. Transgastric views may be useful when assessing LV size and function or papillary muscle and chordal anatomy. ECHO FEATURES OF BILEAFLET VALVE Both leaflets are typically visualized . Opening angle 750 to 900 Closing position 1200 for valves 25 mm & 1300 for valves 27 mm
Three orifices are seen in diastole with highest velocity from central orifice Small flame-shaped washing jets of MR are seen Bileaflet have the largest EOA of all the mechanical valves (2.43.2 cm2) with little intrinsic mitral regurgitation (MR). ECHO features of Tilting disc features Closing angle of disc between 1100 to 1300 & Opening angle of 600 to 800 The Orifices for these valves are Asymmetric Major orifice at the site of forward
Disc excursion (in the direction of flow) & Minor orifice at the site of retrograde disc excursion. The EOA of these valves ranges from 1.5 to 2.1 cm2 Major and minor orifice disc angle ranging from 600 to 800 Normal backflow 5 to 9 mL/beat Marked turbulence is created if the major orifice faces the left ventricular outflow tract (LVOT)
PHV Flow Cx: Important feature. Valve type Flow Characteristics Ball-in-cage prosthetic valve (Starr-Edwards, Edwards Lifescience) Much obstruction and little
leakage. Tilting disc prosthetic valve (Bjrk-Shiley; Omniscience; Medtronic Hall) Less obstruction and More leakage. Bi leaflet prosthetic valves (St. Jude
Medical; Sorin Bicarbon; Carbomedics) Less obstruction and More leakage. Bioprostheses. Little or no leakage Homografts, pulmonary
autografts, and unstented bioprosthetic valves (Medtronic Freestyle, Toronto, Ontario, Canada) No obstruction to flow. 2D ECHO assessment of PHV TIMING OF ECHO CARDIOGRAPHIC FOLLOWUP
Baseline postoperative TTE study should be performed 3-12weeks after surgery, when the Chest wound has healed Ventricular function has improved.
Anaemia with its associated hyperdynamic state has resolved. Bioprosthetic valves Annual echocardiography is recommended after the first 10 years. If symptom of dysfunction echo indicated SOS Mechanical valves routine annual echocardiography is not indicated 2D ECHO ASSESMENT
Valves should be imaged from multiple views, Points to note are Determine the specific type of prosthesis. Confirm the opening and closing motion. Confirm stability of the sewing ring. Presence of leaflet calcification or abnormal echo density (vegetations and thrombi) Confirm normal blood flow patterns Calculate valve gradient Calculate effective orifice area
Detection of Pathologic transvalvular and paravalvular 2D Echo complication detection For bioprostheses, evidence of leaflet degeneration can be recognized leaflet thickening (cusps >3 mm in thickness)-earliest sign calcification (bright echoes of the cusps). Tear (flail cusp). Prosthetic valve dehiscence is characterized by a rocking motion of the entire prosthesis.
An annular abscess may be recognized as an echolucent or echodense irregularly shaped area adjacent to the sewing ring of the prosthetic valve. Doppler Echocardiography in PHV evaluation PRIMARY GOALS OF DOPPLER INTERROGATION Assesment of prosthetic valve obstruction Detection and quantification of prosthetic valve regurgitation
Doppler Assessment of Obstruction of Prosthetic Valves Stenosis Quantitative parameters of Prosthetic valve Stenosis Trans prosthetic flow velocity & Pressure gradients. Valve EOA. Doppler velocity index(DVI). Contour of trans prosthetic jet and acceleration time (AT) For Prosthetic Aortic valve Stenosis
Double envelope spectral doppler Aortic valve: Trans prosthetic valve velocity & Gradient assessment. Take values from multiple transducer position Apical Right parasternal Right supraclavicular Suprasternal notch Take highest velocity from the different values
obtained from various position Transprosthetic velocity and gradient The flow is Eccentric - monoleaflet valves Three separate jets - bileaflet valves Multi-windows examination needed Localised high velocity may be
recorded by continuous wave(CW) Doppler Interrogation through the smaller central orifice of the bileaflet mechanical prostheses overestimation of gradient Prosthetic Heart valve Gradient calculation. Equation P = 4V2
or If LVOT velocity more than 1.5 cm2 P =4 (VPRAV - VLVOT ) 2 2 Limitation of doppler transvalvular Gradient measurement is that it is FLOW DEPENDENT Effective orifice area calculation
(EOA) of Aortic PHV Continuity equation used mostly. EOA PrAV = (CSA LVOT x VTI LVOT) / VTI PrAV This method can be applied even if concomitant aortic regurgitation. Better for bioprosthetic valves and single tilting disc mechanical valves. Underestimation of EOA in case of bileaflet valves. PHT is used only if <200 msec or > 500 msec. Calculation of EOA at the Mitral Prosthetic
valve EOAPrMv = CSA LVOT X VTI LVOT /VTI PrMv Continuity equation cant be applied for mitral PHV EOA calculation if > mild MR/AR present. PHT is also not valied for MPHV EOA calculation as it is influenced by the chronotropy , LA & LV compliance. If PHT significantly delayed (>130msec) or show significant lengthening from the value obtained during the last evaluation
it is useful. How to take measurement for continuity equation VTI LVOT by PW doppler at LVOT at the same location at which LVOT diameter taken ie 0.5 -1 cm distal to the LVOT. VTI PRAV : CW at the Aortic prosthesis CSA LVOT: PLAX zoomed view ie 0.5 -1 cm distal to the LVOT.
Transprosthetic jet contour and Acceleration time :Qualitative index Normal Contour: Triangular & short AT PHVObstruction: Rounded contour with peaking at mid ejection time & prolonged AT(>100msec) DOPPLER VELOCITY
INDEX DVI had a sensitivity, specificity, positive and negative predictive values, and accuracy of 59%, 100%, 100%, 88%, and 90%, respectively for valve dysfunction. DOPPLER VELOCITY INDEX Is the Ratio of the proximal flow velocity in the LVOT to the flow velocity through the aortic prosthesis in aortic PHV or The ratio of flow velocity through the Mitral prosthesis to the flow velocity
across LVOT Time velocity time integrals may also be used in Place of peak velocities ie., DVI for Aotic Valve =VLVOT / VPrAv or VTI LVOT /VTI PrAv
DVI for Mitral Valve = VPr Mv /V LVOT or VTI PrMv/ VTI PrAV DVI can be helpful to screen for valve stenosis, particularly when the Crosssectional area of the LVOT cannot be obtained DVI is always less than one, because velocity will always accelerate through the prosthesis. DVI is not affected by high flow conditions Disadvantage Does not distinguish obstruction due to PPM or intrinsic
dysfunction It depends on the size of LVOT. PROSTHETIC TRICUSPID & PULMONARY VALVE STENOSIS Suspect prosthetic tricuspid stenosis if Prosthetic valve leaflet morphology and moblity abnormal Peak velocity >1.7 m/sec Mean Gradient 6mm of Hg PHT at least 230msec
Evaluation of high gradient across the Prosthetic heart valve Causes of High velocity or gradient across the prosthetic valve
Prosthetic valve stenosis or obstruction. Patient prosthesis mismatch (PPM). High flow conditions. Prosthetic valve regurgitation. Localised high central jet velocity in bileaflet mechanical valves. Increased heart rate. Algorithm for interpreting abnormally high transprosthetic pressure gradients
DETECTION AND QUANTIFICATION OF PROSTHETIC VALVE REGURGITATION Physiologic Regurgitation. Closure backflow (necessary to close the valve) Leakage backflow (after valve closure) Narrow (Jet area < 2 cm2 and jet length <2.5 cm Short in duration
Symmetrical Low(nonaliasing) velocities Regurgitant fraction of <10% to 15%. Pathologic Regurgitation. Always r/o whether Paravalvular or Valvular Patterns of Physiological regurgitation Bioprosthetic Valve: Small central regurgitation Bileaflet valve: Two criss cross jet parallel to the plane of
leaflet opening Tilting Disc: Regurgitation away from the sewing ring at the edge of major orifice Single disc with central strut ( Medronic Hall) Small central jet around the central hole Pathological Regurgitation features Eccentric or Large jet Marked variance on the colour flow density Jet that originates near the sewing ring Visualisation of the proximal flow acceleration
region on the LV side of Mitral valve Prosthetic Mitral regurgitation Echo Evaluation Prosthetic Mitral regurgitation Echo Evaluation Qualitative parameters
Color flow jet areas Flow convergence Jet density Jet contour Pulmonary venous flow Doppler velocity index
Regurgitant jet area calculation is difficult due to artifact & shadowing Retrograde systolic flow in one or more pulmonary vein is specific for significant MR TEE is superior to detect reversal of flow in pulmonary vein mitral prosthesis. PISA method is difficult to apply in PMV regurgitation as eccentric jet or multiple jets Paravalvular regurgitation severity Regurgitant Jet
<10% of the sewing ring : Mild 10- 20 % of the sewing ring : Moderate >20% of the sewing ring : Severe
Limitation of Echo in PHV assessment IN QUANTIFICATION OF PHV REGURGITATION Para valvular jet, Eccentric jet & Multijet difficult to quantify EVALUATION OF PROSTHETIC LEAFLET MOBILTY TTE and TEE has limited sensitivity for the
detection of abnormalities of leaflet morphology and mobility EVALUATION OF PVE TTE and TEE are less sensitive in detection of PVE COMPLICATION OF PROSTHETIC HEART VALVES Complication related to PHV Operative Mortality Perioperative MI
Prosthetic Valve Dehiscence Prosthetic valve endocarditis Thrombo emboli Hemorrhage with anti coagulant therapy Patient-Prosthetic mismatch Hemolysis Prosthetic Valve Dysfunction due to Obstruction
Regurgitation Structural Failure Late Mortality Prosthetic replacement due to complication Patient prosthesis mismatch Patient Prosthesis Mismatch Valve prosthesispatient mismatch (VPPM)
described in 1978 by Dr. Rahimtoola. PPM occurs when EOA of a normally functioning prosthetic valve is too small in relation to the body size resulting in abnormal gradient across the valve. Indexed EOA (EOA/BSA) is the parameter widely used to identify and predict PPM Prevention of PPM Avoided by systematically Calculating the projected indexed EOA of the prosthesis Model with better hemodynamic performance eg Stentless valve
Aortic root enlargement to accommodate a larger size of the same prosthesis model. Supra annular placement: Prevents PPM IN 98% of AVR (The prevention of PPM in the mitral position difficult than in the aortic position because valve annulus enlargement or stentless valve implantation is not an option in this situation) Prosthetic valve thrombus and Pannus Prosthetic valve obstruction
Pure thrombus 75% Pure pannus 10% Combination of pannus and thrombus 12% VALVE THROMBOSIS Definition Any thrombus in the absence of infection attached to or near the operated valve that occclude the path of blood flow or impede the operation of the valves
Pannus It is is a membrane of granulation tissue as an response to healing and is avascular in nature Injured pannus can predispose a thrombotic process and a chronic thrombus can trigger intravascular growth factors that promotes pannus growth. This is more common with tilting disc on the side of minor
orifice. Pannus vs Thrombus THROMBUS Shorter time from valve insertion to valve dysfunction(62 days ) Shorter duration of symptoms (9days) Lower rate of adequate anticoagulation (21%) Longer ( 305 days)
Higher rate of adequate anticoagulation (89 %) Greater total mass length (2.8cm), primarily due to extension into the LA, Mostly it is mobile Smaller -1.2 cm firmly fixed (minimal mobility) to the valve apparatus
Less echo-dense Highly echogenic (due to fibrous composition) Common in aortic position Para valve jet suggests pannus Associated with spontaneous contrast, Common in mitral and tricuspid position
PANNUS Longer(178 days) Structural valve degeneration Structural valve degeneration Definition Any change in function(decrease in one NYHA class or more) of an operated valve including Operated valve dysfunction or deterioration exclusive of infection or thrombus as determined by
the reoperation/autopsy or clinical investigation Wear,fracture,popet escape,calcification, leaflet tear ,stent creep, and suture line disruption of components of an operated valve Structural valve degeneration SVD is the most common cause of Bio PHV failure Freedom from structural valve degeneration
Types of degeneration CALCIFIC DEGERATION NON CALCIFIC DEGERATION ( 30 %) Stented porcine valves : 30- 60% at 15 years Pericardial valves : 86% at 12 years Mortality for reoperation for SVD is 23times than first operation. Sequele of degeneration PHV Stenosis
PHV Regurgitation or Both Mechanical PHV Structural failure Strut fracture Leaflet escape Occluder dysfunction due to lipid adsoption Prosthetic valve infective endocarditis Early endocarditis < 60 days P.O.D- perioperative bacteremia
from skin/wound infections/contaminated intravascular devices. Organisms: Staphylococcus epidermidis, S. aureus, gramnegative bacteria, diphtheroids, and fungi. Late prosthetic-valve endocarditis (>60 days POD) is usually caused by the organisms responsible for native-valve endocarditis, most often streptococci. Site of vegetation Mechanical valves: Between the sewing ring & annulus and
cause paravalvular abscess, dehiscence, peudonaeurysm, fistulas Bioprosthetic valve: IE effects the valve leaflets and cause cusp tear perforation, and vegetation Paravalvular regurgitation Paravalvular regurgitation Causes
Infection Suture dehiscence or fibrosis Calcification of native annulus causing inadequate contact between the sewing ring and annulus More common with the trans catheter aortic valve implantation Mild Paravalvular Regurgitation good prognosis require frequent monitoring
Thank u QUIZ Q No .1 Name of this person? Q.No 2 Name the Complication of this Bileaflet prosthetic valve. Q.No.3
What does this two cinefluroscopy images of the Tricuspid Bileaflet PHV show? ( pictures are of the same patient 8 hrs apart? Q.No.4 What does this spectral doppler tracing show? Tracing taken from A5C through Aortic PHV? Q.No .5. Severe Prosthetic Aortic stenosis include all except
a) Peak velocity > 4m/sec b) Mean Gradient > 35mm of Hg c) DVI >0.25 d) Acceleration Time >100 msec e) EOA : <0.8 Q.No .6 What type of valve is this? a) EDWARD SAPIEN SELF EXPANDABLE b) CORE VALVE BALLOON EXPANDABLE
c) EDWARD SAPIEN BALLOON EXPANDABLE d) CORE VALVE SELF EXPANDABLE Q.No .7 Male patient presented with PUO 1 month after Aortic valve replacement. What is the echo finding? PLAX & SHORT AXIS images. Q.No .8 Para valvular regurgitation is said to be severe if regurgitation is _____% of the sewing ring circumferance?
a) >20% b) >30% c) >40% d) >50% Q.No .8 Features of Physiological regurgitation? A) Jet area < 2 cm2 and jet length <2.5 cm B) Jet area > 2cm2 but < 5cm2 and jet length <2.5 cm
C) Jet area >2cm2 and jet length >2.5cm D) jet area of >5cm2 and jet Length of 2.5 cm Q.No.9 What does this PLAX IMAGES show? Q.No 10 Severity Aortic PPM is defined as a) Indexed EOA 0.65 cm2 /m2 b) Indexed EOA 0.85 cm2 /m2
c) Indexed EOA 1.2 cm2 /m2 d) Indexed EOA 0.9 cm2 /m2 Q.No 11 Probable valve type producing this type of Doppler Spectral signal ? Q.No 12 Identify the abnormality? ANTICOAGULATION MANAGEMENT
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