congenital heart disease

1. AORTIC STENOSIS
* B O O K R E V I E W : M O S S A N D A D A M S
* * M A R Y A M K E S H A V A R Z H E D A Y A T I
* * * A D U L T C O N G E N I T A L H E A R T D I S E A S E
* * * * R A J A E I H E A R T C E N T E R , T E H R A N , I R A N
* * * * * Q A Z V I N U N I V E R S I T Y O F M E D I C A L
S C I E N C E

2. • Valvar aortic stenosis
• most common type of congenital left ventricular outflow tract obstruction : 80% to 85%
•
• subvalvar stenosis: 15% of LVOTO, subvalvar stenosis is more common in males ,
male-to-female ratio =1.5:1 and 2.5:1
• supravalvar stenosis : least common, 1 in 20,000 live births ,Williams–Beuren
syndrome, slight male predominance (52% to 55%)

3. BAV
• 1% of the general population in autopsy studies
•
• males : 65%
• Race  African Americans appearing to have a lower prevalence of both bicuspid
aortic valve and severe aortic stenosis

4. BAV
• the most common congenital abnormality of the aortic valve
• a fibrous ridge, or raphe, at the site of fusion
• 95% of cases, the cusps of a bicuspid valve are unequal in size
• with a raphe frequently present in the larger, fused cusp
• 70% to 85% : fusion occurs between right and left-coronary cusps
• Fusion between the right and the noncoronary cusp is next most common
• fusion between the left and the noncoronary cusp is quite rare
• only∼2% of bicuspid valves develop clinically significant stenosis or insufficiency by
adolescence
• fusion of the right and noncoronary cusps : more risk of significant aortic stenosis or
insufficiency

5. BAV
• Dilation of the ascending aorta or aortic root is commonly seen in association with
bicuspid aortic valves with or without significant stenosis
•
• mild dilation : 50% of pediatric and young adult patients
•
• Moderate or severe dilation :16% and 5% of the patients,
• Significant stenosis does not appear to increase the risk of significant aortic dilation, and
(valves with moderate or greater aortic stenosis have been associated with less dilation of
the aortic root than those with milder stenosis)

7. UNICUSPID AORTIC VALVE
• less common
• complete or partial fusion of two (unicuspid, unicommissural) or all three commissures
(unicuspid, acommissural)
• develop clinically significant disease earlier in life compared with bicuspid valves

11. CALCIFIC AORTIC STENOSIS
• either bicuspid or tricuspid aortic valves
• a common disease in adulthood
• rarely seen in pediatric patients
• Calcification of a bicuspid aortic valve does not generally begin until the fourth decade
•
• sclerosis can be seen as early as the second decade in asymptomatic valves

12. • Tricuspid aortic valves with dysplastic leaflets :
• less frequently than bicuspid or unicuspid valves
• valvar aortic stenosis due to incomplete opening of a “doming” valve ,reduced
effective valve orifice
• annular hypoplasia : Much less commonly, in the setting of additional left-sided
anomalies , spectrum of hypoplastic left heart syndrome

13. ADDITIONAL ANOMALIES
• most common : coarctation of the aorta, PDA , VSD
•
• bicuspid valve : in 20% to 85% of cases of isolated coarctation
• Concentric left ventricular hypertrophy : with hemodynamically significant stenosis
• In cases of severe neonatal aortic stenosis, obstruction to left ventricular outflow in utero
often leads to the development of endocardial fibroelastosis, a diffuse thickening and
scarring of the left ventricular endocardium

14. SUBVALVAR AORTIC STENOSIS
• membranous subaortic stenosis (Discrete subvalvular AS)
• most common form , 70% to 80% of cases
• a thin, fibrous membrane just proximal ( several millimeters) to the aortic valve
•
• The membrane is generally very thin (1 to 2 mm)
• often circumferential
• attachments to the anterior leaflet of the mitral valve

16. • fibromuscular ridge :
• The second most common type, thicker than the membrane
• located slightly inferior of aortic valve
• Pathology : abnormal flow patterns and shear stresses within the left
ventricular outflow tract that lead to endothelial damage, cellular
proliferation, and collagen deposition resulting in the formation of the
fibrous membrane or ridge
SUBVALVAR AORTIC STENOSIS

17. • tunnel-type” obstruction :
• muscular hypertrophy and narrowing of the left ventricular outflow tract
• several centimeters below the valve
• While de novo ,most commonly diagnosed in patients undergone prior congenital heart
surgery due to abnormal flow patterns and shear stresses caused by even mild residual
postoperative subaortic obstruction result in proliferation and hypertrophy
SUBVALVAR AORTIC STENOSIS

18. OTHER ETIOLOGIES OF SUBAORTIC
OBSTRUCTION
• anomalous insertions of mitral valve chordae or accessory atrioventricular valve tissue
(in the setting of a cleft mitral valve or complete atrioventricular septal defect)
• the left ventricular outflow tract “goose-neck deformity” present in complete
atrioventricular septal defects
• posterior malalignment of the infundibular septum
• asymmetric septal hypertrophy as a subtype of hypertrophic cardiomyopathy

19. ASSOCIATED FINDING IN SUBAORTIC STENOSIS
•aortic insufficiency:
• 70% of patients with subaortic stenosis over time
• in some cases related to previous balloon or surgical intervention on the aortic valve
• secondary to valve damage from long-standing exposure to the high-velocity jet caused by the
subvalvar membrane
• aortic valve morphology is most often normal
• bicuspid aortic valve is identified in 10% to 25% of patients

20. • ventricular septal defect : 10% to 48% of patients
• Coarctation of the aorta :
• 6% to 20% of patients with subvalvar stenosis
• sometimes accompanied by additional left-sided anomalies including a
supravalvar mitral ring and a parachute mitral valve

21. PHYSIOLOGY IN AORTIC STENOSIS
• Primary Physiology : left ventricular outflow tract obstruction
• location (the stenosis is above, below, or at the level of the aortic valve) and mechanism of
obstruction affect course and treatment
• In all cases increased afterload
• For preserved left ventricular systolic function and cardiac output, left ventricular outflow
tract obstruction results in increased left ventricular systolic pressure and wall stress and
hypertrophy.
• Ventricular wall stress is directly proportional to ventricular pressure, and inversely
proportional to ventricular wall thickness
• concentric ventricular hypertrophy successfully maintains wall stress within normal limits
• Over time, a persistent pressure load on the left ventricle results in pathologic ventricular
remodeling and development of clinical heart failure.

22. HEART FAILURE
***1- The first negative physiologic effect of ventricular hypertrophy is impaired ventricular
relaxation correlated with the degree of ventricular hypertrophy
• myocyte hypertrophy to fibrosis and cell death
• progressive cardiomyocyte loss , increased collagen replacement ,deterioration of systolic
and diastolic function ,clinical heart failure
• ***2- subendocardial ischemia

23. CLINICAL FEATURES
• gradually progressive disease
• produces symptoms only late in the disease course
• Mild or moderate aortic stenosis : asymptomatic
• moderate to severe aortic stenosis : fatigue, exertional dyspnea, angina, and syncope
• exertional dyspnea was present in all patients with a left ventricular outflow tract gradient of at
least 70 mm Hg, in <20% of patients with a lower gradient
• Angina and syncope are increasingly common with increasing disease severity
• a complaint of dyspnea, angina, or syncope in a patient with known or suspected aortic
stenosis warrants urgent evaluation

24. PHYSICAL EXAMINATION
• vital signs : normal
• tachycardia and tachypnea (in infants with severe disease or older patients who have progressed to left
ventricular failure)
• ***supravalvar aortic stenosis : right arm often demonstrating a systolic pressure 15 to 20 mm Hg higher
than the left (due to the Coanda effect, a phenomenon in fluid dynamics in which a jet stream adheres to
a boundary wall )
• Patients with supravalvar stenosis : systolic hypertension ,widened pulse pressure due to reduced elasticity
of the aorta
• In patients with more than moderate stenosis: laterally displaced left ventricular impulse ,systolic thrill over
the base of the heart (thrill over the suprasternal notch in even mild valvar aortic stenosis)
• S1 : normal
• S2: single or narrowly split in 50% (due to delayed closure of the aortic valve ),
• physiologic splitting of S2 : most reliable examination finding to exclude severe aortic stenosis
• pulmonary valve may close prior to the aortic valve “paradoxical splitting”
• S3 and S4 gallops : common in pediatric patients with left ventricular outflow tract obstruction

25. PHYSICAL EXAMINATION
• The classic murmur : harsh crescendo–decrescendo systolic ejection murmur
• valvar and supravalvar stenosis: the murmur loudest at right upper sternal border
• subvalvar stenosis : murmur better heard at the left mid sternal border
• intensity of murmur: correlates with degree of obstruction
• severe obstruction : parasternal systolic murmur IV–V/VI
• ejection murmur of aortic stenosis often radiates to the carotid arteries
• aortic insufficiency + stenosis : early diastolic decrescendo murmur along the left lower sternal
border
• midsystolic ejection click : An important clue to distinguish aortic valvar stenosis from supravalvar
or subvalvar disease : best heard at the apex , in most cases of dysplastic or bicuspid aortic valves,
regardless of degree of stenosis, constant throughout the respiratory cycle
• severe left ventricular outflow tract obstruction, peripheral pulses are diminished and slightly
delayed in relation to the second heart sound, the classic “parvus et tardus” pulses of aortic stenosis
• severe disease + heart failure : tachycardia, tachypnea, hepatomegaly ,jugular venous distension,
pulmonary rales

26. ELECTROCARDIOGRAPHY
• EKG findings : neither highly sensitive nor highly specific for severe stenosis (even in
pediatrics
• the presence of left ventricular hypertrophy and a strain pattern on EKG is an independent
predictor of the development of heart failure in asymptomatic patients with aortic stenosis
and is associated with increased myocardial fibrosis on MRI and increased risk of
cardiovascular death

27. RADIOGRAPHY
• normal heart size
•
• dilated ascending aorta
• One exception : in neonate ,significant cardiomegaly , enlargement of the left
ventricular and left atrial borders, Pulmonary edema

28. ECHOCARDIOGRAPHY
• information about the aortic valve and left ventricular outflow tract (anatomic and
physiologic )
• AHA/ACC guidelines : class I recommendation for the diagnostic evaluation of suspected
aortic stenosis
• Supravalvar stenosis : more difficult to fully evaluate by transthoracic echocardiography
•

29. • peak instantaneous gradient is generally higher than the catheter-derived gradient ,
While the mean Doppler-derived gradient may more closely approximate the peak-to-
peak gradient (pressure recovery)

31. • severe stenosis = peak velocity across the aortic valve of ≥4.0 m/s or a mean gradient
across the valve of ≥40 mm Hg
• low gradient due to decreased cardiac output, an aortic valve area ≤1.0 cm2 or indexed
valve area ≤0.6 cm2/m2 is consistent with severe stenosis
• Moderate stenosis = a peak velocity between 3.0 and 3.9 m/s or a mean gradient
between 20 and 39 mm Hg
• mild stenosis = peak velocity of 2.0 to 2.9 m/s and a mean gradient ≤20 mm Hg

32. OTHER MODALITIES
*** TEE :
• limited role in evaluation of aortic stenosis in pediatric patients
• The exception : in the operating room
• better define the mechanism of obstruction preoperatively
• adequacy of relief of obstruction
• intraoperative complications
• postoperative : residual lesions
*** 3-D echocardiography : useful anatomic information , mechanism of
complex subaortic obstruction

33. •MRI : clarify the level and mechanism of anatomic obstruction, degree of aortic dilation,
aortic insufficiency, , degree of myocardial fibrosis via late gadolinium enhancement( a marker for
fibrosis is an independent predictor of mortality in adults with aortic stenosis )
• Exercise Testing : exercise capacity, hemodynamic response to exercise, and exercise-
related ST-segment changes = correlated with disease severity in pediatric patients with aortic stenosis
*** Guidelines:
• ETT in asymptomatic severe AS = class IIa recommendation
• avoiding exercise testing in any symptomatic patient
• Patients who develop symptoms = symptomatic, despite the lack of symptoms at baseline, and aortic
valve intervention is recommended
• AHA guidelines for catheter-based intervention in pediatric patients : class I recommendation for
aortic balloon valvuloplasty for patients with a peak-to-peak gradient of at least 40 mm Hg who are
asymptomatic at baseline but develop either symptoms or EKG changes with exercise .

34. CARDIAC CATHETERIZATION
• gold standard to measure pressure gradients and determine the need for intervention
• therapeutic tool for patients with valvar aortic
• using light conscious sedation to mimic resting hemodynamic conditions as closely as
possible. General anesthesia can alter systemic vascular resistance, which can impact
measured pressure gradients
• measurements performed prior to administration of iodinated contrast, cause elevations in
the systolic and end-diastolic blood pressure.
• pressure gradients can be underestimated in low cardiac output

35. • Mechanisms of aortic stenosis : subvalvar, valvar, or supravalvar
• a left ventriculogram define the morphologic substrate (discrete subaortic membrane
versus tunnel-like obstruction)
• assess ventricular function
• degree of left ventricular hypertrophy
• assess degree of aortic insufficiency
• presence of aortic root ectasia commonly observed in patients with valvar aortic stenosis

36. NATURAL HISTORY
***Valvar aortic stenosis
• is a progressive disease
• higher gradient at presentation are risk factors for more rapid progression, the need
for intervention, and increased mortality
• increase in peak systolic velocity of only 0.04 m/s/yr

37. NATURAL HISTORY
***Subvalvar Aortic Stenosis : generally a progressive disease
• Independent predictors of disease progression : increased gradient at diagnosis,
attachment of the subaortic membrane to the mitral valve, aortic valve thickening at
diagnosis, and decreased distance between the aortic valve and the subaortic
•
• aortic insufficiency is another important physiologic anomaly associated with subvalvar
aortic stenosis, generally worsens with time , Risk factors for progression of aortic
insufficiency include increased mean gradient at diagnosis and increased time since
diagnosis

38. NATURAL HISTORY
***Supravalvar Aortic Stenosis:
- generally worsens with time
- Interestingly, the pulmonary stenosis often frequently found in the same patients
generally improves over time ,The reason for this discrepancy is unknown

39. MEDICAL MANAGEMENT
• Neonates with critical aortic stenosis must be stabilized prior to surgical or catheter-based
interventions, and patency of the ductus arteriosus must be maintained with prostaglandin E1
• hypertension management in patients with a bicuspid aortic valve or aortic stenosis.
Hypertension is a significant risk factor for aortic root dilation and further elevates left
ventricular afterload .
• Anti-hypertensive therapy is a class I recommendation for adults with asymptomatic aortic
stenosis with both beta-blockers and ACE-inhibitors being considered reasonable choices.
• In the setting of aortic stenosis with aortic root dilation, angiotensin receptor blockers were
previously thought to have the added potential benefit of inhibiting TGF-β, which has been
implicated in aortic root dilation in Marfan syndrome and other connective tissue disorders.
However, a recent randomized controlled trial failed to show any benefit of losartan compared
to atenolol in preventing aortic root dilation among Marfan syndrome patients and the role of
angiotensin receptor blockers in the management of aortic root dilation related to bicuspid
aortic valve is unclear.
• antibiotic prophylaxis is not indicated for left ventricular outflow tract obstruction, The
exceptions to this are patients who have undergone aortic valve replacement or in patients
with a prior history of infective endocarditis.

40. FOLLOW UP
• The ACC/AHA guidelines for the management of aortic stenosis recommend transthoracic
echocardiogram every 6 months to 1 year for asymptomatic patients with severe stenosis,
every 1 to 2 years for patients with moderate stenosis, and every 3 to 5 years for patients
with mild stenosis
• Infants with even mild aortic stenosis should be re-evaluated every 4 to 8 weeks
• Symptom development requires urgent evaluation in any patient

41. EXERCISE
• asymptomatic patients with mild aortic stenosis (defined as peak-to-peak gradient <30 mm
Hg, mean Doppler gradient <25 mm Hg, peak instantaneous Doppler gradient <40 mm Hg)
may participate in all sports without restriction
• all competitive sports should be avoided in patients with severe aortic stenosis (peak-to-peak
gradient >50 mm Hg, mean Doppler gradient >40 mm Hg, peak instantaneous Doppler
gradient >70 mm Hg)
• Recommendations are more complex for asymptomatic patients with moderate stenosis
(peak-topeak gradient 30 to 50 mm Hg, mean Doppler gradient 25 to 40 mm Hg, peak
instantaneous Doppler gradient 40 to 70 mm Hg). If patients with moderate stenosis have no
more than mild left ventricular hypertrophy, a normal exercise test, and do not exhibit a strain
pattern on baseline EKG, they may participate in sports with low static component and low to
moderate dynamic component (including golf, bowling, baseball or softball, and volleyball). If
these patients have no history of tachycardia, they may also participate in sports with
moderate static and low dynamic components (including diving, archery, and horseback or
motorcycle riding).

42. PREGNANCY
• Severe aortic stenosis may be poorly tolerated in pregnancy, with hemodynamic changes
including increased preload, decreased afterload, and increased heart rate
• A dilated aortic root also is a risk factor for complications during pregnancy
• Intervention on the aortic valve is recommended for patients with severe aortic stenosis prior
to pregnancy
• For patients with severe stenosis who do become pregnant, intervention on the aortic valve
during pregnancy is recommended if there is hemodynamic deterioration or the development
of NYHA class III or IV heart failure symptoms

43. THERAPEUTIC CARDIAC CATHETERIZATION
• Balloon aortic valvuloplasty is typically reserved for patients with valvar aortic stenosis,
although there is evidence that thin, discrete subaortic membranes may be effectively treated
with balloon angioplasty as well
• indications for balloon aortic : For asymptomatic children and young adults, a peak systolic
ejection gradient ≥50 mm Hg
•
• in symptomatic patients (angina or syncope), patients with resting or exercise-induced ECG
changes, or patients planning to become pregnant or participate in competitive sports, a
gradient ≥40 mm Hg is often used
• calcific aortic valve disease, seen more typically in older adults, often does not respond to
aortic valvuloplasty

44. SURGICAL MANAGEMENT
• either valve repair or valve
• the dysplastic but noncalcified valves of pediatric patients have proven more amenable to
surgical intervention
• The most common residual lesion following a surgical valve repair is stenosis, rather than
insufficiency
• freedom from reintervention was approximately 80% to 90% at 10 years, with early mortality
of 2%
• The most durable replacement valve is a mechanical prosthesis. While excellent long-term
outcomes can be achieved with mechanical valves (up to 90% survival and freedom from
reintervention at 20 years)
• Another issue with mechanical valves is the lack of appropriately sized options for infants and
small children, as well as the inability of the valve to grow with the patient.

45. ROSS PROCEDURE
• The final option for surgical aortic valve replacement is the Ross procedure, in which the
patient's pulmonary valve is used as an autograft. Often the procedure of choice for small
children, the Ross offers the advantages of a high quality replacement valve that will grow
with the patient. The need to replace the right ventricle to pulmonary artery conduit over
time necessitates future reoperation (or possible catheter placement of a valve such as the
Melody valve), though the hope is that conduit exchange will entail less morbidity and
mortality than reintervention on the aorta.
• ∼75% actuarial survival at 15 years
• 40% of pediatric patients developing at least moderate neoaortic insufficiency after 6 years

47. • Subvalvar Aortic Stenosis The surgical approach to repairing
subvalvar aortic stenosis depends greatly on the type of obstruction present
• . discrete fibrous membrane : Repair involves relatively straightforward membrane
resection, a low-risk procedure ,mortality between 1% and 2% ,early repair using a
peak gradient of 40 mm Hg as an indication for surgery
• Subaortic membranes are known to recur, and reoperation rates between 0.6% and
1.8% per year
• Risk factors for membrane recurrence : increased peak gradient at the time of
diagnosis ,early age at diagnosis , and distance <5 mm between membrane and
valve
• Complex or tunnel-like subaortic resection requires more extensive surgery to correct
• survival outcomes are still generally excellent
• recurrent obstruction and reoperation is more common(15% to 50% )

48. –Supravalvar Aortic Stenosis
– outcomes are inferior to those of valvar and subvalvar stenosis, with 3% to 9% early
mortality
• reoperation 34% at 20 years
• The most common indication for reoperation is aortic valve dysfunction
• The coronary arteries must be carefully assessed both with preoperative imaging,
direct examination in the operating room
• concomitant repair or replacement of the aortic valve occurs in up to 40%