aortic stenosis audrone laforgia, md advisor: dr. nelson cicu lecture, 03/04/2011

Aortic StenosisAortic Stenosis

Audrone LaForgia, MDAudrone LaForgia, MDAdvisor: Dr. NelsonAdvisor: Dr. Nelson

CICU Lecture, 03/04/2011CICU Lecture, 03/04/2011

Congenital Heart DiseaseCongenital Heart DiseasePhysiologic PresentationsPhysiologic Presentations

Contractile dysfunctionContractile dysfunction Obstruction of Systemic Blood FlowObstruction of Systemic Blood Flow

Ventricular Pressure OverloadVentricular Pressure Overload Ductal-dependant Systemic Blood FlowDuctal-dependant Systemic Blood Flow

Volume OverloadVolume Overload Left-to-Right Shunt/Excessive Pulmonary FlowLeft-to-Right Shunt/Excessive Pulmonary Flow

Obstruction of Pulmonary Blood FlowObstruction of Pulmonary Blood FlowRight-to-left Shunt/Diminished Pulmonary FlowRight-to-left Shunt/Diminished Pulmonary FlowDuctal-dependant Pulmonary Blood FlowDuctal-dependant Pulmonary Blood Flow

TranspositionTranspositionParallel CirculationsParallel Circulations

Single Ventricle PhysiologySingle Ventricle Physiology

EpidemiologyEpidemiology

Defective development of cardiac valves occurs in Defective development of cardiac valves occurs in 20-30% of patients with CHD20-30% of patients with CHD

AS occurs in 3-6% of all patients with CHDAS occurs in 3-6% of all patients with CHD Male:female – 4:1Male:female – 4:1

Theory: diminished flow across AoV contributes to Theory: diminished flow across AoV contributes to underdevelopment of the left heart (hypoplastic LV, underdevelopment of the left heart (hypoplastic LV, aortic arch, etc.)aortic arch, etc.)

PathologyPathology

Valvar – 71%Valvar – 71% Subvalvar – 23%Subvalvar – 23% Supravalvar – 6%Supravalvar – 6%

Pathology – Valvar ASPathology – Valvar AS

Bicuspid AoV - MCBicuspid AoV - MC Unicuspid AoV - lessUnicuspid AoV - less Stenosis of tricuspid AoV – the leastStenosis of tricuspid AoV – the least

Bicuspid AoV with fused commissure Bicuspid AoV with fused commissure and an eccentric orifice; prone to and an eccentric orifice; prone to calcification later in lifecalcification later in life

Bicuspid AoVBicuspid AoV

Bicuspid AoV EchoBicuspid AoV Echo

Pathology – Subvalvar ASPathology – Subvalvar AS

AkaAka Subaortic stenosis Subaortic stenosis

Simple diaphragm:Simple diaphragm:– AkaAka Discrete membranous Discrete membranous – 10% of all AS cases10% of all AS cases– 2/3 with associated cardiac lesions – 2/3 with associated cardiac lesions –

VSD, PDA or COAVSD, PDA or COA

Discrete Membranous Discrete Membranous Subaortic StenosisSubaortic Stenosis


Tunnel stenosis – long tunnel-like fibromuscular Tunnel stenosis – long tunnel-like fibromuscular narrowing of the LVOT:narrowing of the LVOT:– Often with hypoplasia of ascending aorta, AoV ring or thickened Often with hypoplasia of ascending aorta, AoV ring or thickened

AoV leafletsAoV leaflets– Extremely rare – 71 cases reported since 1961Extremely rare – 71 cases reported since 1961

Usually associated with other Usually associated with other LV anomaliesLV anomalies – – Shone complexShone complex::– Supramitral ringSupramitral ring– Parashute MVParashute MV– Subaortic stenosisSubaortic stenosis– COACOA

Note associations above – secondary to decreased Note associations above – secondary to decreased flow through the left heartflow through the left heart

Tunnel-like Subaortic StenosisTunnel-like Subaortic Stenosis


Hypertrophic cardiomyopathy (HCM), Hypertrophic cardiomyopathy (HCM), formerly known as Idiopathic formerly known as Idiopathic hypertrophic subaortic stenosis hypertrophic subaortic stenosis (IHSS), – primary disorder of the heart (IHSS), – primary disorder of the heart musclemuscle

Pathology – Supravalvar ASPathology – Supravalvar AS

Annular constriction above the valve at Annular constriction above the valve at the upper margin of sinus of Valsalvathe upper margin of sinus of Valsalva

May be associated with hypoplasia of May be associated with hypoplasia of ascending aortaascending aorta

Often associated withOften associated with Williams (or Williams (or Williams–Beuren) syndromeWilliams–Beuren) syndrome

Williams–Beuren syndromeWilliams–Beuren syndrome

Developmental delayDevelopmental delay Mental retardationMental retardation Pectus excavatumPectus excavatum ClinodactilyClinodactily Characteristic (“elfin”) Characteristic (“elfin”)

faciesfacies Multiple PA stenosesMultiple PA stenoses Initial hypercalcemia Initial hypercalcemia

PathologyPathology

Closed Transventricular Aortic Valvotomy for Closed Transventricular Aortic Valvotomy for Critical Aortic Stenosis in Neonates: Critical Aortic Stenosis in Neonates:

Outcomes, Risk Factors, and ReoperationsOutcomes, Risk Factors, and Reoperations

Brown JW et al. Ann Thorac Surg. 2006;81:236-242. Brown JW et al. Ann Thorac Surg. 2006;81:236-242.

Few ConsiderationsFew Considerations

Critical AS with normal MV and normal-sized LV is Critical AS with normal MV and normal-sized LV is much less common than with HLHS as it is a much less common than with HLHS as it is a continuum – rationale for fetal interventioncontinuum – rationale for fetal intervention

Valvar AS is relatively common isolated defect, but Valvar AS is relatively common isolated defect, but it only occasionally presents as critical it only occasionally presents as critical (symptomatic) in newborns; usually (symptomatic) in newborns; usually unicuspidunicuspid AoV AoV

LV dysfunction develops secondary to extremely LV dysfunction develops secondary to extremely high LV afterloadhigh LV afterload

Transition at BirthTransition at Birth

During fetal life, obstruction to the left During fetal life, obstruction to the left ventricle does not lead to decreased ventricle does not lead to decreased systemic perfusion as its outflow can be systemic perfusion as its outflow can be diverted via PDA diverted via PDA

Left-sided obstruction causes Left-sided obstruction causes decompensation after birth because decompensation after birth because postnatal changes in circulation prevent RV postnatal changes in circulation prevent RV from performing the work of LV – FO closesfrom performing the work of LV – FO closes

After BirthAfter Birth

L to R shunt across FO is present due to L to R shunt across FO is present due to increased diastolic pressure in LV; O2 Sat in increased diastolic pressure in LV; O2 Sat in RV and PA is increased as well as in PDA RV and PA is increased as well as in PDA and systemic circulationand systemic circulation

In critical AS R to L shunt across PDA is In critical AS R to L shunt across PDA is necessary to maintain systemic perfusion as necessary to maintain systemic perfusion as there is there is no flowno flow across AoV across AoV

Pathophysiology - Decreased Pathophysiology - Decreased Systemic PerfusionSystemic Perfusion

Clinical ManifestationsClinical Manifestations

Hemodynamic significance depends on Hemodynamic significance depends on degree of obstruction and tends to be degree of obstruction and tends to be progressiveprogressive

Mild to moderate AS – asymptomaticMild to moderate AS – asymptomatic Severe AS – failure to thrive and tachypnea Severe AS – failure to thrive and tachypnea Critical AS – CHF within the first few weeks Critical AS – CHF within the first few weeks

((PDA dependent lesionPDA dependent lesion))

Differential DiagnosisDifferential Diagnosis

Decreased systemic perfusion:Decreased systemic perfusion:– Obstructive heart diseaseObstructive heart disease– Myocardial dysfunction from sepsisMyocardial dysfunction from sepsis– Anemia/polycythemiaAnemia/polycythemia– Hypocalcemia/Hypoglycemia/Metabolic Hypocalcemia/Hypoglycemia/Metabolic

acidosisacidosis

Physical Exam – Critical ASPhysical Exam – Critical AS

Stable during the first hours of life, or Stable during the first hours of life, or even until 3-4 weeks after birtheven until 3-4 weeks after birth

After ductal constriction CHF develops After ductal constriction CHF develops – poor feeding, pallor, diaphoresis, – poor feeding, pallor, diaphoresis, tachypnea, irritability – low CO/shocktachypnea, irritability – low CO/shock

Physical Exam – Critical ASPhysical Exam – Critical AS

Severe respiratory distress due to Severe respiratory distress due to increased pulmonary venous pressureincreased pulmonary venous pressure

Gallop rhythm - CHF Gallop rhythm - CHF Peripheral pulses absent or weakPeripheral pulses absent or weak Poor perfusionPoor perfusion HepatomegalyHepatomegaly Severe metabolic acidosisSevere metabolic acidosis

What About The Murmur?What About The Murmur?

High pitch, grade 2-4/6 systolic ejection High pitch, grade 2-4/6 systolic ejection murmur is best heard at the right 2murmur is best heard at the right 2nd nd

intercostal space, with radiation to the neck intercostal space, with radiation to the neck and apexand apex

In severe, but NOT critical AS as there is no In severe, but NOT critical AS as there is no flow across AoV in critical ASflow across AoV in critical AS

In general, SEM within the first 24 hours of In general, SEM within the first 24 hours of life – think of AS or PSlife – think of AS or PS

CXR – Critical ASCXR – Critical AS

CardiomegalyCardiomegaly Pulmonary venous Pulmonary venous

congestioncongestion

Management – Critical ASManagement – Critical AS

Intubation/PPVIntubation/PPV

PGE1 at higher doses to reopen the ductPGE1 at higher doses to reopen the duct

May need inotropes and diuretics for CHFMay need inotropes and diuretics for CHF

Percutaneous balloon valvuloplasty – Percutaneous balloon valvuloplasty – optimal procedure for critically ill neonates – optimal procedure for critically ill neonates – to relieve afterloadto relieve afterload

ManagementManagement

MedicalMedical SurgicalSurgical

Medical ManagementMedical Management

Percutaneous balloon valvuloplastyPercutaneous balloon valvuloplasty

Complications:Complications:– Transection of the femoral and iliac arteryTransection of the femoral and iliac artery– Perforation of the aortaPerforation of the aorta– Pericardial tamponadePericardial tamponade– Avulsion of AoV leafletAvulsion of AoV leaflet– Massive AR later – 10-30%Massive AR later – 10-30%– Perforation of MV or LVPerforation of MV or LV – Vascular complications more pronounced in neonates Vascular complications more pronounced in neonates

Surgical ManagementSurgical Management

Advantage – direct inspection of AoV, Advantage – direct inspection of AoV, more precise commissurotomy, and more precise commissurotomy, and shaving of any excess myxomatous shaving of any excess myxomatous tissue/nodules on the leafletstissue/nodules on the leaflets


Depends on LV function rather than sizeDepends on LV function rather than size

Univentricular repair – if LV is severely Univentricular repair – if LV is severely fibrotic and unable to generate high fibrotic and unable to generate high pressures when obstructed, it may not be pressures when obstructed, it may not be capable of supporting systemic blood flow capable of supporting systemic blood flow even after obstruction is relieved:even after obstruction is relieved:– Norwood procedureNorwood procedure


Biventricular repair:Biventricular repair:– Close aortic valvotomy without CPB with dilators or Close aortic valvotomy without CPB with dilators or

balloon cathetersballoon catheters– Aortic valve commissurotomy – divided within 1 mm of Aortic valve commissurotomy – divided within 1 mm of

aortic wall; adequate leaflet attachments necessary to aortic wall; adequate leaflet attachments necessary to avoid ARavoid AR

– Aortic valve replacementAortic valve replacement– Tunnel-like subaortic AS – aortoventriculoplasty (Tunnel-like subaortic AS – aortoventriculoplasty (Konno Konno

operationoperation))– Discrete subaortic AS – excision of the membraneDiscrete subaortic AS – excision of the membrane– Supravalvar AS – widening of stenotic area using a patchSupravalvar AS – widening of stenotic area using a patch

Closed Transventricular Closed Transventricular Aortic ValvotomyAortic Valvotomy

Aortic Valve ReplacementAortic Valve Replacement

Mechanical valveMechanical valve Porcine bioprosthesisPorcine bioprosthesis AoV allograftAoV allograft Pulmonary valve autograft (Pulmonary valve autograft (Ross procedureRoss procedure) – ) –

autologous pulmonary valve replaces AoV; aortic or autologous pulmonary valve replaces AoV; aortic or pulmonary allograft replaces pulmonary valvepulmonary allograft replaces pulmonary valve

Anticoagulation required for mechanical valvesAnticoagulation required for mechanical valves Durability is an issue with allograftsDurability is an issue with allografts

Neonatal Isolated Critical Aortic Valve Neonatal Isolated Critical Aortic Valve Stenosis: Balloon Valvuloplasty or Stenosis: Balloon Valvuloplasty or

Surgical ValvotomySurgical Valvotomy

Balloon valvuloplasty had higher re-Balloon valvuloplasty had higher re-intervention rate but shorter hospital intervention rate but shorter hospital and ICU stay, reduced immediate and ICU stay, reduced immediate morbidity and was associated with less morbidity and was associated with less severe AR.severe AR.

Zain Z et al. Heart Lung Circ. 2006;15(1):18-23.Zain Z et al. Heart Lung Circ. 2006;15(1):18-23.

Neonatal surgical aortic Neonatal surgical aortic commissurotomy: predictors of outcome commissurotomy: predictors of outcome

and long-term resultsand long-term results

Predictors of increased mortality in Predictors of increased mortality in neonates undergoing surgical valvotomy:neonates undergoing surgical valvotomy:– Size of aortic annulusSize of aortic annulus– Endocardial fibroelastosisEndocardial fibroelastosis– Fractional shortening <35%Fractional shortening <35%– Low aortic gradientLow aortic gradient

Balloon valvuloplasty offers poor results Balloon valvuloplasty offers poor results when performed in patients with complex when performed in patients with complex anomalies. anomalies.

Agnoletti G et al. Ann Thorac Surg. 2006;82(5):1585-92. Agnoletti G et al. Ann Thorac Surg. 2006;82(5):1585-92.

In General…In General…

Both surgical valvotomy and transcatheter Both surgical valvotomy and transcatheter balloon valvuloplasty are associated with balloon valvuloplasty are associated with mortality and morbidity and with residual or mortality and morbidity and with residual or recurrent valve dysfunction.recurrent valve dysfunction.

Both are Both are palliativepalliative procedures: sooner or procedures: sooner or later, re-intervention is likely. later, re-intervention is likely.

The choice between the two varies The choice between the two varies according to the local expertise and/or according to the local expertise and/or preference. preference.

Most Important – Freedom Most Important – Freedom Rate From Re-interventionRate From Re-intervention

Balmer et al.Balmer et al. showed that AR was frequently showed that AR was frequently observed after balloon valvuloplasty; freedom rate observed after balloon valvuloplasty; freedom rate from re-intervention was only 35% at 3 years.from re-intervention was only 35% at 3 years.

At this age, there is no other choice than Ross At this age, there is no other choice than Ross procedure or AoV replacement by allograft.procedure or AoV replacement by allograft.

Survivors after primary valvotomy in most surgical Survivors after primary valvotomy in most surgical series have 10-year freedom rates from re-series have 10-year freedom rates from re-intervention between 55 and 90%.intervention between 55 and 90%.

At this interval, the AoV annulus is usually big At this interval, the AoV annulus is usually big enough to accommodate an adult-size mechanical enough to accommodate an adult-size mechanical valve, if needed. valve, if needed.

Therapeutic DilemmaTherapeutic Dilemma

Newborn with Newborn with severesevere, but NOT critical AS – no CV , but NOT critical AS – no CV decompensation and LV function is normaldecompensation and LV function is normal

Demands on myocardium over the first weeks of life Demands on myocardium over the first weeks of life are large:are large:– Increase in metabolic demand with growthIncrease in metabolic demand with growth– Decrease in Hb level – CO increasesDecrease in Hb level – CO increases– Anemia causes systemic vasodilation - low DBP, Anemia causes systemic vasodilation - low DBP,

tachycardiatachycardia– Decrease coronary blood flow to hypertrophied LVDecrease coronary blood flow to hypertrophied LV– LV ischemia/dysfunction weeks after birthLV ischemia/dysfunction weeks after birth– May not recover after obstruction is relieved May not recover after obstruction is relieved

NeurodevelopmentNeurodevelopment

Albers EL et al. Pediatr Res. 2010;68(1).Albers EL et al. Pediatr Res. 2010;68(1).

Thank YouThank You

Bicuspid AoV EchoBicuspid AoV Echo

Physical ExamPhysical Exam

Ross-Konno procedureRoss-Konno procedure

aortic stenosis audrone laforgia, md advisor: dr. nelson cicu lecture, 03/04/2011

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