PATHOPHYSIOLOGY OF COARCTATION OF AORTA

1. PATHOPHSIOLOGY
COARCTATION OF AORTA

2. NOMENCLATURE
coarctatis (Latin)- Contracted, tightened or pressed together.
The first description of this condition is attributed to Johann Freidrich Meckel, a Prussian
anatomist who demonstrated the case of an 18-year-old female in 1750
CONGENITAL NARROWING OF UPPER DESCENDING THORACIC AORTA
ADJACENT TO SITE OF ATTACHMENT OF DUCTUS ARTERIOSUS

3. 4
6
Thoracic coarctation is a manifestation of abnormal development of the embryologic left fourth and sixth aortic
arches

4. FLOW THEORY
DUCTUS SLING THEORY
THEORIES

5. FLOW THEORY
• In the normal fetus the aortic isthmus receives only 10% of the combined
ventricular output, which explains that the normal neonatal isthmus diameter is
only about 70% to 80% of the diameter of the ascending aorta.
• Decreased blood flow in the aortic isthmus in the embryonic
period
• Due to reduced perfusion, the isthmus region cannot develop properly and
remains hypoplastic. In such cases there is often not only localized coarctation,
but also tubular hypoplasia of the aortic arch proximal to the isthmus.
• Intracardiac lesions diminish the volume of left ventricular outflow promote
development of coarctation in the fetus by reducing flow through the aortic
isthmus
“NO FLOW, NO GROW”!

6. DUCTUS SLING THEORY
In 1855, Skoda speculated that the constriction of the
aorta is related to the closure of the ductus arteriosus
extending into the walls of the aorta,a proposal which is
referred to as the Skodiac hypothesis
Coarctation develops as the result of migration of ductal
smooth muscle cells into the periductal aorta, with
subsequent constriction and narrowing of the aortic
lumen.This concept is concordant with the clinical
observations that coarctation often becomes manifest after
ductus closure and that it may be palliated in the
newborn with prostaglandin E1 infusion.

7. OTHER FACTORS
• GENETIC
TURNERS SYNDROME
22q DELETION
• NEURAL CREST CELLS -Believed to play role in pathogenesis of juxtaductal
aorta

8. CLASSIFICATION
•EDWARDs(Preductal,Post ductal,Juxtaductal)
•AMATO et al
I - Primary CoA
II- CoA with isthmic hypoplasia
III- CoA with tubular hypoplasia
•BONNET(Infantile & Adult)
•Surgical classification:
I - Isolated CoA
II - CoA with VSD
III - CoA with complex intra-cardiac anomaly

9. In the infantile group, the ductus arteriosus
is open and there is a tubular narrowing of
the isthmus of the aorta proximal to the
ductus. The ductus supplies the blood flow
to the descending aorta
In the adult type of
coarctation the ductus is
closed and there is a
shelf-like narrowing within
the lumen of the aorta

10. PREDUCTAL TYPE
1. PDA is patent and large and provide
blood flow to lower extremity.
2. Tubular narrowing of isthmus
3. No shelf like narrowing in aorta.
4. Minimal post stenotic dilatation of
aorta.
5. Minor enlargement of intercostal
arteries.
POSTDUCTAL TYPE
1. The ductus is closed and no
longer acts as a shunt.
2. No narrowing of isthmus.
3. Shelf like narrowing with in the
aorta in juxtaductal position.
4. Post stenotic and prestenotic
aorta is dilated.
5. Intercostal arteries are grossly
dilated.
The key difference between these two types is the patent ductus arteriosus provides blood flow to the lower
extremity in the preductal (infantile) group and the ductus arteriosus is closed in the postductal (adult)
coarctation

11. MORPHOLOGY
Most commonly is a discrete stenosis
The most common site is at the junction of the aortic isthmus, the arterial duct
or ligament, and the descending aorta

12. • C/s area reduced by at least 50%.
• An intimal and medial malformation and a
prominent posterior infolding (the posterior shelf)
which often extends around the entire
circumference of the aorta . In the majority of
cases, the shelf is formed by ductal tissue
• Histologic examination reveals thick intimal and
medial ridges that protrude posteriorly and
laterally into the aortic lumen
Usually intimal hypertrophy ( intimal veil )
extends the shelf circumferentially and further
narrows the

13. TUBULAR HYPOPLASIA / PREDUCTAL/
INFANTILE COARCTATION
- INVOLVES ISTHMUS & DISTAL ARCH
- PRESENT IN INFANCY
- INTRACARDIAC LESIONS COMMON

14. Common association • Uncommon
• VSD
• AORTIC STENOSIS/AORTIC
ATRESIA.
• MS/MR
• VSD WITH LVOTO
• TOF
• CONGENITAL PULMONARY
STENOSIS
• PULMONARY ATRESIA
• TRICUSPID ATRESIA
• RT AORTIC ARCH

15. Associated pathology
1. Collateral Formation
2.. Aneurysm formation of intercostal arteries
3. Aortic valve * bicuspid (27-45%) * stenosis
4. Intracranial aneurysm * berry type intracranial aneurysm
5. Associated cardiac anomaly * 85% of neonates presenting
COA

16. COLLATERAL CIRCULATION
Collateral arteries bypass the obstruction and augment perfusion to the lower body.Although rarely
present in infants, collateral circulation gradually develops throughout childhood in those with subcritical
coarctation
Between aorta proximal to and distal to coarctation.
More developed in adult or postductal type as ductus is closed and collaterals are the only source of
blood supply to the lower half of body.
Inflow primarily from branches of the subclavian artery
Outflow primarily into upper DTA.

17. Site Inflow Outflow
Lateral chest wall 1. 3rd to 6th ant. I/C art. from IMA (First two ant
I/C art do not participate)
2. Lat. Thoracic art. From 2nd part of Axillary
art
3. I/C br. from musculophrenic art.
1. Ant. Br of 3rd to 9th post. I/C art
2. Arteria Aberrans
Around the Scapula 1. Transverse cervical & transverse scapular art
from thyrocervical trunk of subclavian art
2. Suprascapular art from Subclavian art
3. Subscapular art from 3rd part of Axillary art
1. Muscular br from post div of 3rd to 7th
post I/C art
Diaphragm 1. Musculophrenic art from IMA 1. Inf phrenic art from Abd Aorta
2. Lower post I/C art (ant div)
Upper abdominal wall 1. Sup epigastric art (terminal br of IMA) 1. Inf epigastric art (br of EIA)
2. Ant div of upper lumbar art
Around the spinal cord 1. Ant spinal art from vertebral art
2. Post spinal art from Post inf cerebellar art or
vertebral art
1. Radicular art from post div of post I/C and
lumbar art
Collateral flow predominantly arise from:
1. Subclavian artery and its branches: Internal thoracic artery , intercostal artery, scapular artery, cervical artery, vertebral artery, spinal
artery.
2. Epigastric artery.

18. Pseudocoarctation
• It is a rare condition
presumably resulting from the
congenital elongation of the
aortic arch .
• The elongation leads to
redundancy and kinking of the
aorta which may appear
similar to the coarctation but
has no actual obstruction to
the blood flow. (Absence of
narrowing of Aortic lumen)
• There is no actual pressure
gradient in pseudocoarctation.
• There is tendency of
dilatation and aneurysm
formation due to the turbulant
flow in aorta.

19. PATHOPHYSIOLOGY
• Upper body HTN, systolic gradient across CoA
• When obstruction develops rapidly
•  ventricle fails to take up increased afterload
•  lv failure
•  increased LAP & PV congestion
• increased shunting across foramen ovale and
hypoperfusion of distal organs
•  acidosis, oliguria, gut ischemia, cold clammy
extremities.

20. • If ductus closes gradually allows time for LVH
and collateral formation.
• If ductus is wide open RV output provides lower
body perfusion.

21. Natural History
• Incidence 50: 1lakh live births. Common in males.
• 5-7% of congenital heart disease
• 80% of these are isolated CoA ± PDA
• Natural history of untreated isolated CoA
1st month:10% - acute CHF
1st year: 20% - CHF
1-4 yrs: 10% - chronic CHF
• Thus 50% die within 10 yrs of life
• 14-20yrs of age: 20% will die d/t Bacterial
endocarditis, aortic rupture or intracranial
hemorrhage
• 20-50 yrs of age: 20% d/t heart failure secondary
to HT or valvular heart disease

22. • MC causes of death
-heart failure(26%)
- infective endocarditis(25%)
- aortic rupture(21%)
-intracranial haemorrhage(13%)

23. CLINICAL FEATURES
• NEONATES AND INFANTS
• CHILDHOOD
• ADULTS

24. NEONATES AND INFANTS
• When coarctation presents in infancy, it often presents as a catastrophic
illness.
• Congestive heart failure and shock can occur suddenly as the ductus
arteriosus closes.
• A large proportion of these infants have coarctation with important
associated structural lesions such as a ventricular septal defect or aortic
stenosis.
• In an infant with severe coarctation and a large ventricular septal defect,
the sudden onset of ventricular dysfunction, low cardiac output, shock,
and acidosis classically develops around 8 to 10 days of life.
• Multiorgan system failure, particularly renal failure and/or necrotizing
enterocolitis, and death occur rapidly unless definitive medical and
surgical interventions are provided rapidly

25. NEONATES AND INFANTS
SYMPTOMS OF CONGESTIVE HEART FAILURE
 FAST BREATHING
 POOR FEEDING
 BREATHELESSNESS
 SWEATING
 FAILURE TO THRIVE
 COLLAPSE

26. NEONATES AND INFANTS
• TACHYPNOEA
• INTERCOSTAL RECESSION
• PROFOUND SKIN MOTTLING
• SLOW CAPILLARY REFILL
• PERPHERAL CYANOSIS
• ABSENT /WEAK FEMORAL PULSES
• OVERACTIVE PRECORDIUM
The presence of palpable femoral pulses in the first day or two of life does not exclude the diagnosis of coarctation or interruption,
since flow of blood to the lower body may be maintained antegradely through the persistently patent arterial duct. Once symptoms
occur, the femoral pulses are usually weaker, or absent

27. BEYOND INFANCY
• Childhood—Usually asymtomatic,
Hypertention
• Adolescence & adult life--
--Asymtomatic
--reduced femoral pulse
--murmur, hypertention
--Headache,epitaxis,claudication
--rarely with CCF,
dissection,intracranial hemorrhage

28. BEYOND INFANCY
• CVA – 2nd – 3rd decade
• IE / Endarteritis – 2nd – 4th decade
• Rupture / Dissection – 3rd – 4th decade
• HT & CAD

29. General Examination
• Normal
• Broad chest and narrow leg
• Left arm may be smaller than right
• Impaired growth in infants with CHF
• Turner’s syndrome (XO)

30. CVS examination
•Pulse
• Brachio-femoral delay
Left radial pulse weak – LSCA stenosis
Right radial pulse weak – aberrant RSCA

31. Blood pressure
Systolic blood pressure gradient
Difference b/w UL & LL BP > 20mmHg
On echo- gradient across CoA– 20mmHg
On cath withdrawl gradient > 20mmHg
The gradient will increase with exercise.
Hypertension

32. • The combination of weak or absent femoral pulses
together with a gradient in pressure between the limbs
is therefore virtually pathognomonic of aortic
coarctation.

33. Differential cyanosis
• (PDA with Right to Left shunt) Ductal-dependent
perfusion of the lower half of the body results in
differential cyanosis. If there is critical aortic coarctation,
the lower half of the body is supplied with venous blood
via a right-to-left shunt at the ductal level. A relevant
difference in pulse oximetry exists between the right arm
(preductal) and the legs (postductal).
Left ventricular pressure and volume overload may
produce a prominent, heaving ventricular impulse at
the apex.

34. Auscultation
• S1 Normal
• S2 Normal
• S3 LVF
• S4 severe HT
. A constant systolic ejection click may be heard at the apex, signaling the presence of a bicuspid
aortic valve

35. Murmurs
1. Systolic
2. (A grade 2–3/6 systolic ejection murmur originating from the coarctation itself is usually best heard at the base and the left interscapular area
posteriorly.If the coarctation is severe, the systolic murmur may be long and spill into diastole)
3. Collateral –
4. Continuous murmurs ,delayed onset crescendo- decrescendo in ant thorax, right infraclavicular, left sternal
and suprasternal.
5. Associated intracardiac lesions create other murmurs.
 Functional – ESM of BAV
 PSM at the lower left sternal border or apex.–VSD/MR
• MDM at the apex-MS

36. Thank you