Bicuspid Aortic ValveBicuspid Aortic Valve

06/01/200706/01/2007

Bicuspid aortic valveBicuspid aortic valve

Definition:Definition:– Two functional aortic valve leaflets with Two functional aortic valve leaflets with

two complete commissurestwo complete commissures AKA “Bicommissural aortic valve”AKA “Bicommissural aortic valve”

Bicuspid aortic valveBicuspid aortic valve

Felt to represent a complex Felt to represent a complex continuumcontinuum– Unicommissural, Bicommissural, Unicommissural, Bicommissural,

Tricuspid, and QuadricuspidTricuspid, and Quadricuspid

Not simply a fusion of two normal Not simply a fusion of two normal cuspscusps

Bicuspid aortic valveBicuspid aortic valve

Three criteria:Three criteria:    

1.) Unequally sized cusps1.) Unequally sized cusps

– Larger leaflet is the "conjoined" leafletLarger leaflet is the "conjoined" leaflet    

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Bicuspid Aortic ValveBicuspid Aortic Valve

2.) Presence of a central ridge 2.) Presence of a central ridge (raphe)(raphe)      – Usually in the center of the conjoined Usually in the center of the conjoined

leafletleaflet

Bicuspid Aortic ValveBicuspid Aortic Valve

3.) Smooth cusp margins3.) Smooth cusp margins

– Excludes tricuspid valves which fused Excludes tricuspid valves which fused due to inflammatory processes (eg, due to inflammatory processes (eg, rheumatic fever)rheumatic fever) Irregularity and scarring within the raphe.Irregularity and scarring within the raphe.

MorphologyMorphology

Orientation:Orientation:    – Anterior-posterior Anterior-posterior

Left leaflet Left leaflet Right (conjoined) leafletRight (conjoined) leaflet

– Left-rightLeft-right Anterior (conjoined) leaflet Anterior (conjoined) leaflet Posterior leafletPosterior leaflet

PhysiologyPhysiology

Normally functioning bicuspid valveNormally functioning bicuspid valve– Abnormal folding and creasingAbnormal folding and creasing– Restricted motionRestricted motion– Turbulent flowTurbulent flow

Prolonged stress leads to valve Prolonged stress leads to valve damagedamage

StatisticsStatistics

Estimated overall incidence of 1-2%Estimated overall incidence of 1-2%

M:F at least 2:1M:F at least 2:1

Familial clustering suggests AD with Familial clustering suggests AD with variable penetrancevariable penetrance

No race or geographical predilectionNo race or geographical predilection

Associated AnomaliesAssociated Anomalies

Left dominant coronary arteryLeft dominant coronary artery– Up to 50% Up to 50%

10% with tricuspid valve10% with tricuspid valve

Short left main coronary arteryShort left main coronary artery– Less than 5mmLess than 5mm

Associated AnomaliesAssociated Anomalies

Coarctation of the aortaCoarctation of the aorta Interrupted aortic archInterrupted aortic arch

– >50% have bicuspid aortic valve>50% have bicuspid aortic valve

Associated AnomaliesAssociated Anomalies

Turner's SyndromeTurner's Syndrome– Up to 30%Up to 30%

William's SyndromeWilliam's Syndrome– Up to 10%Up to 10%

ImagingImaging

EchocardiographyEchocardiography– Modality of choiceModality of choice

Long-axis shows systolic doming due to Long-axis shows systolic doming due to limited valve openinglimited valve opening

Short-axis allows examination of the Short-axis allows examination of the commisures, leaflet morphology, and commisures, leaflet morphology, and mobility.mobility.

RadiographsRadiographs

Usually normal in pediatric Usually normal in pediatric populationpopulation

Aortic root enlargementAortic root enlargement

Left ventricular enlargementLeft ventricular enlargement

May see calcified raphe or leafletsMay see calcified raphe or leaflets

CT/MRICT/MRI

Allows for evaluation of the aorta and Allows for evaluation of the aorta and coronary arteriescoronary arteries

Functional informationFunctional information

http://medirec.ncvc.go.jp/

PathologyPathology

Aortic StenosisAortic Stenosis

Aortic InsufficiencyAortic Insufficiency

Bacterial EndocarditisBacterial Endocarditis

Aortic DissectionAortic Dissection

Aortic StenosisAortic Stenosis

Poorly functioning valves may have Poorly functioning valves may have incomplete systolic openingincomplete systolic opening

Responsible for 80-95 % of aortic Responsible for 80-95 % of aortic valve disease detected in infancyvalve disease detected in infancy– May cause rapid deteriorationMay cause rapid deterioration– Progression over years is more commonProgression over years is more common

Aortic Stenosis Aortic Stenosis

Bicuspid valve may be prone to Bicuspid valve may be prone to accelerated agingaccelerated aging– Sclerosis begins in the second decade of Sclerosis begins in the second decade of

lifelife– Estimated that 50% of adults with Estimated that 50% of adults with

severe AS have bicuspid valves. severe AS have bicuspid valves.

Aortic StenosisAortic Stenosis

Cusps oriented in the AP direction Cusps oriented in the AP direction demonstrate more rapid progressiondemonstrate more rapid progression

Presence of risk factors can also Presence of risk factors can also expedite the processexpedite the process– High LDL, high lipoprotein (A) and High LDL, high lipoprotein (A) and

smokingsmoking

Aortic InsufficiencyAortic Insufficiency

Isolated AIIsolated AI

AI with aortic root dilatation AI with aortic root dilatation 

Aortic InsufficiencyAortic Insufficiency

Isolated AIIsolated AI– Prolapse of redundant larger cuspProlapse of redundant larger cusp

Rarely severeRarely severe

Aortic InsufficiencyAortic Insufficiency

Disruption of the elastic tissue within Disruption of the elastic tissue within the upper aortic ring/sinotubular the upper aortic ring/sinotubular junction junction – May occur due to inherent abnormalityMay occur due to inherent abnormality– May be due to coarctation of the aorta May be due to coarctation of the aorta

or bacterial endocarditisor bacterial endocarditis Often severe with high mortalityOften severe with high mortality

Bacterial Endocarditis Bacterial Endocarditis

Estimated 10-30% of patients with Estimated 10-30% of patients with bicuspid aortic valvebicuspid aortic valve– 25% of cases of endocarditis occur on bicuspid 25% of cases of endocarditis occur on bicuspid

valvesvalves

– Tetralogy of Fallot, VSD, and MVP are the other Tetralogy of Fallot, VSD, and MVP are the other lesions associated with SBElesions associated with SBE

Prophylactic antibiotics for dental/surgical Prophylactic antibiotics for dental/surgical proceduresprocedures

Bacterial EndocarditisBacterial Endocarditis

Responsible for half of cases of Responsible for half of cases of severe AI in patients with bicuspid severe AI in patients with bicuspid valvevalve– Many due to cusp perforationMany due to cusp perforation

Unexplained systemic emboli should Unexplained systemic emboli should raise suspicionraise suspicion

Aortic Dissection Aortic Dissection

Approximately 5% of patientsApproximately 5% of patients– Etiology is unclearEtiology is unclear

Abnormal response to hemodynamic stressAbnormal response to hemodynamic stress– Cystic medial necrosis similar to Marfan’sCystic medial necrosis similar to Marfan’s– Dysfunctional microfibrillar proteins, endothelial Dysfunctional microfibrillar proteins, endothelial

nitric oxide synthetase, etc.nitric oxide synthetase, etc.

Medical Management Medical Management

LifestyleLifestyle– Exercise, heart healthy diet, no smokingExercise, heart healthy diet, no smoking

Cholesterol and hypertensive Cholesterol and hypertensive medicationmedication

Medical ManagementMedical Management

Surveillance echocardiographySurveillance echocardiography

Early surgical referralEarly surgical referral

First-degree relative screeningFirst-degree relative screening

Surgical TreatmentSurgical Treatment

Severe valvular dysfunction or aortic Severe valvular dysfunction or aortic root dilatationroot dilatation

Symptomatic patientsSymptomatic patients

Evidence of abnormal LV dimensions Evidence of abnormal LV dimensions and function and function

Surgical TreatmentSurgical Treatment

Pediatric casesPediatric cases– Balloon ValvuloplastyBalloon Valvuloplasty

Without calcified valvesWithout calcified valves Isolated Aortic InsufficiencyIsolated Aortic Insufficiency

– Valve RepairValve Repair Valve replacement Valve replacement

– With or without aortic root replacementWith or without aortic root replacement Prosthetic/Bioprosthetic/HomograftProsthetic/Bioprosthetic/Homograft Ross procedureRoss procedure

ReferencesReferences Fedak PWM, Verma S, David TE, Leask RL, Weisel RD, Butany J. Clinical and Fedak PWM, Verma S, David TE, Leask RL, Weisel RD, Butany J. Clinical and

pathophysiological implications of a bicuspid aortic valve. pathophysiological implications of a bicuspid aortic valve. Circulation. Circulation. 2002; 106: 2002; 106: 900–904 900–904

Ward, C. Clinical significance of the bicuspid aortic valve. Ward, C. Clinical significance of the bicuspid aortic valve. HeartHeart 2000 83: 81-85 2000 83: 81-85 Pediatric Cardiac SurgeryPediatric Cardiac Surgery, Mavroudis et al., 3rd edition, Mosby, St. Louis., Mavroudis et al., 3rd edition, Mosby, St. Louis. Aboulhosn, J, Child, JS. Left ventricular outflow obstruction: subaortic stenosis, Aboulhosn, J, Child, JS. Left ventricular outflow obstruction: subaortic stenosis,

bicuspid aortic valve, supravalvar aortic stenosis, and coarctation of the aorta. bicuspid aortic valve, supravalvar aortic stenosis, and coarctation of the aorta. CirculationCirculation. 2006 Nov 28;114(22):2412-22.. 2006 Nov 28;114(22):2412-22.

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