TRICUSPID ATRESIA

Dr Bijilesh uSenior Resident,

Dept. of Cardiology,Medical College, Calicut

- Perloff ‘s text book of congenital heart diseases - Moss and Adams ‘s text book of congenital cardiology - Rudolph text book of pediatric cardiology - Freedom’s natural and modified natural history of cong.heart diseases - Andreson text book of congenital heart disease - Figenbaum’ text book of echocardiography - Hurst’s heart disease - Braunwald’ heart diseases - Langman’s Embryology

References

Defined as congenital absence or agenesis of the tricuspid valve, with no direct communication between the right atrium and right ventricle

• Incidence : 0.06 per 1000 live births

• Prevalence : 1- 3% of CHD (Report of New England Regional Infant Cardiac Program – 1980)

HISTORY

• First reported by Kreysig in 1817• Clinical features reported by Bellet and

Stewart in 1933• Taussig and Brown in 1936

EMBRYOLOGY

• Early embryogenesis - process of expansion of inlet portion of right ventricle coincides with development of AV valves

• Failure of this process - atresia of tricuspid valve & absent inlet portion of right ventricle

• Embryological insult occurring later in gestation - Less common variety - with well formed but fused leaflets

• If valve fusion incomplete - tricuspid stenosis

ANATOMY

Muscular

Membranous

Atrioventricular

• Most common type – muscular (89%)

• Dimple or a localized fibrous thickening in the floor of RA at expected site of tricuspid valve.

• Membranous type - membranous septum forms floor of the RA at the expected location of TV

• May be associated with absent pulmonary valve

leaflets

• Atrioventricular canal type Extremely rare (0.2%) Leaflet of the common AV valve seals off the only entrance into RV

MORPHOLOGICAL CONSIDERATIONS

RA & ASD• The right atrium is enlarged and hypertrophied.

• Interatrial communication is necessary for survival

• Stretched patent foramen ovale - ¾ cases

• True ASD less common - ostium secundum type

• Rarely patent foramen ovale is obstructive and may form an aneurysm of fossa ovalis

• Sometimes large enough to produce mitral inflow obstruction

LA & LV

• Left atrium may be enlarged, especially when pulmonary blood flow is increased

• Mitral valve is morphologically normal - rarely incompetent

• LV is enlarged and hypertrophied

Right ventricle

Small and hypoplastic

Inflow or sinus portion absent

Trabecular portion & outflow or conus region often well developed

Size of the RV varies – depends on size of VSD

With a large VSD or TGA - RV larger

When VSD is small - only the conus is present

VSD in Tricuspid Atresia

Associated VSD - 90% of individuals during infancy

Usually perimembranous Can be muscular /malalignment types

Restrictive VSD’S cause subpulmonic obstruction in pts with NRGA subaortic obstruction in pts with TGA

At birth VSD is usually restrictive- permitting adequate but not excessive PBF

40% of these defects close spontaneously/ decrease in size - acquired pulmonary atresia

Majority of defects close in the first yr of life

Classification - KUHNE

Type 1 Normally related great arteriesType 2 D-transposition of great arteriesType 3 L- Transposition of great arteries

Type 1

Normally related great arteries (70 – 80%) a. Intact IVS with pulmonary atresia( 9%) b. Small VSD and pulmonary stenosis( 51%) c. Large VSD without pulmonary stenosis ( 9%)

Type II

D-transposition of great arteries (12 – 25%)

a. VSD with pulmonary atresia( 2%) b. VSD with pulmonary stenosis( 8%) c. VSD without pulmonary stenosis(18%)

Type 3

L- Transposition or malposition of great arteries (3-6%)

Associated with complex lesions Truncus arteriosus Endocardial cushion defect

Additional cardiovascular abnormalities- 20%

• Coarctation of aorta – 8%• Persistent left SVC• Juxtaposition of atrial appendages -50% of TA with TGA• Right aortic arch

• Abnormalities of mitral apparatus- cleft in AML,MVP ,direct attachment of leaflets to papillary muscles

PHYSIOLOGY- TA

• Obligatory rt to left shunt at atrial level• LA receives both the entire systemic and pulmonary

venous return

• Entire mixture flows into LV - sole pumping chamber

TA WITH NRGA

• Pulm artery blood flow is usually reduced • Restrictive VSD - zone of subpulmonic stenosis.

• LV overload is curtailed but at the cost of cyanosis• 90% of cases

PHYSIOLOGY

• When VSD is non restrictive and pulmonary vascular resistance is low

PBF and LV volume over load - excessive Cyanosis is mild

PHYSIOLOGYTA WITH NRGA

TA with TGA• VSD is almost always non-restrictive and PS usually

absent• Low PVR > abundant pulmonary arterial blood flow• Minimal cyanosis,marked LV volume overload

• With restrictive vsd or infundibular narrowing →diminished syst circulation →metabolic acidosis and shock

PHYSIOLOGY

SEX PREDILECTION

• TA with NRGA - Equal frequency in males & females

• TA with TGA - male preponderance

- no male preponderance with juxtaposition of atrial appendages

GENETICS

• Specific genetic causes - remain to be determined in humans

• FOG2 gene may be involved • Validated only in animal studies

• 22q11 deletion • Familial recurrence is low • Recurrence in siblings is only about 1%

NATURAL HISTORY

• Few infants survive beyond 6 months without surgical palliation

• Intense hypoxia and death ensue unless ductus is patent unless adequate systemic to PA collaterals present

TA with NRGA with an intact IVS

TA with NRGA & SMALL VSD

• VSD closes spontaneously or become excessively obstructive - majority die by one year

• Rarely a favorable balance achieved b/w VSD & PBF permitting survival from 2nd to 5th decades

NATURAL HISTORY

TA with NRGA & LARGE VSD.

• Excessive PBF > vol. overload of LV and CCF• Patients usually do not fare well

• Some have lived to ages 4 to 6 years• Long survivals reported between ages 32 and 45 yrs

- in exceptional cases

NATURAL HISTORY

TR. ATRESIA WITH TGA

• Same poor longevity patterns hold for TA with TGA and large VSD

• Exceptional survivals to mid-late teens reported

• TA with TGA with subaortic stenosis ( restrictive VSD) - ominous combination

NATURAL HISTORY

Overall survival in infants with TA

• 1 year- 72%.• 5 years- 52%.• 10 years- 46% Franklin et al 1972 -1987, 237 patients

Probability of surviving for 1 year was 64% and to 8 years was 55% The overall surgical mortality for the palliative procedures was 35.8%

Survival of patients presenting in infancy with tricuspidatresia to the Toronto Hospital for Sick Children, Tame et al , 101 patients, 1970 - 1984

Physical examination- appearance

• Dysmorphic facies - Cat-eye syndrome - congenital coloboma

• JVP - a wave amplitude increase due to restrictive interatrial communication. - Y descent is slow

Precordium

• LV impulse without an RV impulse in a cyanotic patient

• Gentle RV impulse - TA with non restrictive VSD and a well developed RV

• Palpable thrill if VSD is restrictive

AUSCULTATION

• First heart sound is single • Second usually single - soft pulmonic component -

occasionally present

• TA with NRGA - prominent murmur of restrictive VSD – holosystolic maximal at mid to lower LSB

TA with TGA & increased PBF

• Holosystolic murmur – across VSD• S2 – single & loud• S3• MDM

AUSCULTATION

Pulmonary vascular resistance – high

• VSD murmur vanishes

AUSCULTATION

• TA with TGA - coexisting pulmonic or subpulmonic stenosis - midsystolic murmur – loudness and length vary inversely with degree of obstruction

AUSCULTATION

ECG• Tall peaked right atrial P

waves - Himalayan P waves• LV hypertrophy • Absence of RV forces in

precordial leads

• QRS axis - left and superior - type 1 - LAD or normal - type 2

CHEST X-RAY- TA WITH NRGA AND SMALL VSD

• Pulmonary vascularity reduced• Pulmonary artery segment – inconspicuous• Heart size – normal

• Right cardiac border superior convexity - enlarged RA

• Inferior part flat or receding - absence of RV

• LAO – Humped appearance of right cardiac border

CXR - TA with TGA - no obstruction

• Lungs – plethoric• LV, LA, RA – enlarged

• Right cardiac border no hump-shaped

contour – RV is relatively well

developed

CXR - TA with TGA and PS

• Pulmonary blood flow is normal or reduced• Prominent RA• Convex LV • Narrow vascular pedicle

ECHOCARDIOGRAM• Presence of an imperforate

linear echo density at the location of normal TV

• Presence and size of the interatrial communication• Presence and size of a VSD• Relationship of the aorta and pulmonary artery

• Size of the RV and pulmonary arteries• Presence and severity of infundibular or pulmonary

stenosis• Presence and size of the ductus arteriosus• Presence of aortic isthmus narrowing or coarctation• Degree of mitral regurgitation • Left ventricular function

CARDIAC CATHETERIZATION

• Limited role at presentNewborn• Define sources of pulmonary blood flow • Associated anomalies not clearly defined by echo • TA with TGA - Obstruction at VSD or infundibulum• Therapeutic role for balloon atrial septostomy

• Prior to Fontan - Pulm.Vascular resistance - Pulmonary artery size - Pulmonary artery distortion - by previous surgery• Older patients without definitive palliation - detect collaterals from aorta - lungs

CARDIAC CATHETERIZATION

HEMODYNAMIC DATA • Right atrial pressure is slightly higher than LAP• Prominent ‘a ‘wave in the right atrium -interatrial communication is restrictive

• LV systolic and EDP – normal• LVEDP may increase with large VSD as PVR drops

and LV volume overload ensues

• Oxygen saturation (Sao2) in systemic venous return - lower than normal - diminished Sao2 in systemic arterial blood• Sao2 of pulmonary venous return - normal

• LA and LV saturations - diminished - obligatory R-L shunt

INITIAL MEDICAL MANAGEMENT

• Maintain patency of the ductus before cardiac catheterization or planned surgery

• Given as an infusion• .025 – 0.1 mg/kg/mt• Potential for apnea• Fever , siezure, hypotension

PGE1

• Balloon atrial septostomy may be done as part of initial catheterization to improve the RA-LA shunt

SURGICAL CARE

Palliative

Corrective therapy

PALLIATIVE SURGERY DECIDED IN TERMS OF

Decreased pulmonary flow

Increased pulmonary flow

FOR ↓ PBF

• PBF - increased by surgical creation of an aortopulmonary shunt

• Blalock & Taussig - Subclavian artery - ipsilateral PA• Potts - Descending aorta – LPA• Waterston-Cooley - Ascending aorta – RPA

• Modified Blalock-Taussig shunt - Gore-Tex interposition graft - Subclavian artery - PA• Central aortopulmonary fenestration - Gore-Tex shunt

• Glenn shunt • Superior vena cava – RPA• End-to- end

• Improves PBF and Sa o2• No risk of pulmonary HTN

• Pulmonary AV malformations later

↑ PBF

• Pulmonary artery banding - In patients with tricuspid atresia type II

CORRECTIVE SURGERY

• Fontan and Kreutzer - physiologically corrective operation

- complete separation of the systemic and pulmonary circuits

CHOUSSAT CRITERIA• Age at operation – 4 and 15 yrs - not strictly followed nowadays• Normal sinus rhythm• Normal systemic venous connections• Normal right atrial size

• Normal pulmonary arterial mean pressure - > = 15 mm Hg

• Low pulmonary vasc resistance - 4 woods units/m2• Adequate sized PA with diameter > 75% of aorta• Normal LVEF (>60%)• Absence of MR• Absence of complicating factors from previous

surgeries

• THANK YOU.