Post on 23-Feb-2016
description
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.