The word coarctation has been derived

from latin word ‘COACTERE’, meaning to

contract.

Definition of hypoplasia

* Proximal arch : 60% of ascending aorta

* Distal arch : 50% of ascending aorta

* Isthmus : 40% of ascending aorta

1. Definition

A congenital narrowing of upper descending thoracic aorta adjacent to the site of attachment of ductus arteriosus.

2. History

Morgagni : 1st description in 1760

Bonnett : postductal & preductal type in 1903

Crafoord : 1st coarctation repair in 1944

Vorsschulte : prosthetic onlay graft or vertical incision and transverse closure in 1957

Waldhausen : subclavian patch aortoplasty in 1966

Robert gross: 1938 reported possible complication

of severe haemorrhage and paraplegia after

repair of CoA.

Occurrence rate: 0.2-0.6/1000 live births

Represents 5-8% of all congenital heart disease.

8th most common congenital heart defect.

Two theories

1. The flow theory

2. The ductal sling theory

Any congenital anomaly that reduces the flow through left

side heart and inturn through aortic isthmus in intrauterine life

leads to poor development and ultimately coactation of

aorta.

Holds true for infantile or preductal type of coactation.

Can explain occurrence of coactation with obstructive

lesions of left side like aortic stenosis, bicuspid aortic valve,

congenital mitral stenosis, VSD, shones complex.

Also explain why the coarctation is not seen with right side

obstructive lesions like TOF, PS, TA.

In patients with no associated intracardiac defects the flow

theory does not explain the occurrence of CoA.

For these patients the ductal sling theory holds good.

SKODA more than 100 years ago postulated that it is the abnormal extension of contractile ductal tissue into the

aorta which is responsible for pathogenesis of CoA.

Resected specimen shows the extension of ductal tissue in

circumferencial sling extending from ductus arteriosus and into the surrounding aorta. Contraction and fibrosis of this

ductal tissue sling at the time of ductal closure would lead to

formation of obstructing shelf with in the aorta .

Bonnet in 1903 divided the patients into 2 groups : infantile

type and adult type.

Later infantile type were known by name of preductal type

and adult type was known by name of postductal type.

The entity juxtaductal CoA is now a days used to denote

adult type.

PREDUCTAL TYPE1. 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 stenoticdilatation of aorta.

5. Minor enlargement of intercostal arteries.

POSTDUCTAL TYPE1. 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.

3 groups

1. Group I: patients with isolated CoA

2. Group II : patients of CoA with VSD

3. Group III: patients of CoA with complex

intracardiac anomalies other than

simple VSD.

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.

There is no actual pressure gradient in pseudocoarctation.

There is tendency of dilatation and aneurysm formation due

to the turbulant flow in aorta.

Occurs in 0.5 – 2% cases of coarctation.

Etiology: congenital or related to other diseases like rubella,

takayashu arteritis, von recklinghausen’s disease.

Narrowing is diffuse in 1/3rd cases and circumsccribed in 2/3rd

of cases.

Diagnosis is angiography.

Treatment is by patch aortoplasty or by bypass graft.

1. Collateral circulation2. Aneurysm formation of intercostal arteries

* 3rd, & 4th rib notching * after 4 years of age

3. Coronary artery dilatation and tortuosity* due to LVH

4. Aortic valve* bicuspid (27-45%) * stenosis ( 6 - 7%)

5. Intracranial aneurysm* berry type intracranial aneurysm in some patients

6. Associated cardiac anomaly* 85% of neonates presenting COA

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.

There is progressive enlargement of collateral blood vessels around the coarctation segment.

Collateral flow predominantly arisese from:

1. Subclavian artery and its branches: Internal thoracic artery ,

intercostal artery, scapular artery, cervical artery, vertebral artery, spinal artery.

2. Epigastric artery.

1. Incidence* 5-8% of CHD (5 per 10000 live births)* Isolated CoA (82% of total CoA)

male:female = 2:1CoA + VSD 11%, COA + other cardiac anomalies 7%

* Complex CoA ; no sex difference2. Survival of pure CoA

* 15% : CHF in neonate or infancy* 85% : survive late childhood without operation* 65% : survive 3rd decade of life (2% at 60 years)

3. Bacterial endocarditis : common in 1st 5 decades4. Aortic rupture : 2~3rd decade5. Intracranial lesion : subarachnoid hemorrhage(cong. Berry aneurysm)

Congestive heart failure(26%)

Bacterial endocarditis (25%)

Spontaneous rupture of aorta (21%)

Intracranial haemorrhage(13%)

Narrowed aorta produces increased left ventricular afterload and wall stress, left ventricular hypertrophy, and congestive heart failure.

Systemic perfusion is dependent on the ductal flow and collateralization in severe coarctation

Bimodal distribution

Group 1 : presents in first week of life

Group 2 : presents in childhood and adolescent

They have ductal dependent circulation.

Comes to light after closure of ductus with cardiovascular

shock , renal failure and acidosis. They are a medical

emergency.

Due to less collateral flow in infancy ischemia of organs distal

to coarctation occurs.

At same time sudden increase in LV afterload leads to acute

CHF.

Management includes ventillation , sedation, correction of

acid base balance, prevent hypothermia, prevent

hypoglycemia, maintain optimum perfusion by inotropes and

PGE1 infusion to keep ductus patent followed by surgical

intervention when organ functions were optimised.

Majority of patients are asymptomatic and presents with

hypertension on routine examination.

Symptomatic patients may presents with :

1. Headache and epistaxis due to systemic hypertension

2. Claudication due to reduced blood flow to lower extremity

3. Increased incidence of aneurysm of circle of willis leading to

stroke

4. Aortic aneurysm proximal or distal to coarctation

5. Aortic dissection

6. Atherosclerotic heart disease with MI

7. Congestive heart failure.

8. Bacterial endocarditis (fever).

Diagnosis in new born

Diagnosis in children and adult

Newborn with severe CoA and ductus closure will present in

shock , renal failure, acidosis.

Physical examination: tachycardia, tachypnoea, pale

appearance, lower extremity pulses absent, upper extremity pulses are thready.

Child is hypotensive, liver enlarged

CXR shows cardiomegaly and evidence of CHF.

ECG shows left ventricular strain pattern

2 D echo shows lack of pulsatile flow in descending aorta,

coarctation site and associated cardiac anomaly ,

anatomical details of arch.

Cardiac catheterization: not routinely done but can be done

in patients with suspected complex congenital cardiac

anomalies.

CT angiography: in cases where cardiac cath is not necessary but imaging of arch is not adequate CT

angiography is indicated to see anatomy of arch.

Mostly asymptomatic

Upper extremity hypertension with diminished femoral pulses.

ECG: reveals LVH and LV strain pattern.

CXR Shows:

1. Rib notching(inferior border of 3-9 ribs) if patient is above 4

years of age due to erosion byenlarged collaterals.

2. Classic 3 sign due to dilatation of LSCA , narrowing of

coarctation site and dilatation of post stenotic segment.

3. Cardiomegaly

4. E sign on barium filled oesophagus

2 D echo: mostly diagnostic and shows all the necessary

details, a shelf is seen posteriorly in coarctation segment.

Cardiac catheterization study is required only if there are

associated intracardiac anomalies, a question with regards to collaterals and when visualization by 2 D echo is poor.

MRI is more beneficial in older children for anatomy of arch.

Indications for operation

1. Reduction of luminal diameter greater

than 50% at any age

2. Upper body hypertension over 150mmHg

in young infant ( not in heart failure )

3. CoA with congestive heart failure

at any age

General considerations

Specific techniques

Advantages and drawbacks of different

techniques

Complications and management.

Approach:

1. Posterolateral thoracotomy through 3rd or 4th ICS.

2. Median sternotomy approach is better in patients with

associated cardiac anomalies that are to be repaired simultaneously.

Arterial pressure monitoring lines are placed in right radial

artery and femoral artery.

In cases where rt subclavian artery arises below the coarctation segment then instead of radial line use temporal

artery for proximal aortic pressure monitoring.

Multiple chest collaterals are ligated and divided individually

The lung is retracted anteriorly and mediastinal pleura

overlying the coarctation segment is incised.

The descending aorta , left subclavian artery , isthmus of

aorta, ductus arteriosus and transverse aortic arch distal to left carotid artery is mobilised.

ABOTT ARTERY: this artery is not found in normal subjects but is

seen in CoA patients arising from posterior wall of aortic arch

or lt subclavian artery. When encountered it should be

ligated.

Maintain proximal aortic pressure high during cross clamp to

provide adequate arterial pressure distal to the clamp to

prevent paraplegia.

In adults 160-200 mm hg , in children 100-120mmhg

The distal aortic pressure should not < 45mm hg

If the distal aortic pressure falls below 45 mmhg, following

steps are to be taken

1] use plasma expanders

2] use iontrops

3]relocate the clamp if possible

4]use of partial left heart CPB with left atrial & descending

aortic cannulation

5] prevent acidosis

6] never use SNP

1] resection & end to end anastomosis

2] prosthetic patch aortoplasty

3] prosthetic interpositio graft

4] resection with extended end to end

anastomosis

5]subclavian flap aortoplasty

6] balloon dilatation angioplasty

7] bypass grafts

Described by crafoord & nylin 1944 in adults

Described by kerklin in 1955 in infant

Narrowed coarctation segment is excised with direct end to

end circumferential anastomosis of aorta

Ductus is ligated & divided at the same time

High rate of recoarctation at surgical

site[ 20-86%] particularly in the age of < 1

yr

This technique does not address issue of

hypoplastic transverse arch

Not possible in older children as arch &

descending aorta are more fixed &

difficult to mobilise

Use of silk suture instead of monofilament

suture

Inadequate resection of ductal tissue

Lack of growth at circumferential suture

line

Lack of growth of hypoplastic transverse

arch

Introduced by vosschulte in 1957 mainly for

patients of 1-16 yrs.

access is through left 4th ICS

Aorta is incised longitudinally in region of

coarctation with prolongation of incision well

above & below

Patch extent upto left subclavian artery

Is isthmus is also hypoplastic, the patch may be

extended upto left carotid artery with clamp

position proximal to left carotid artery

The collateral vessels are preserved & do not

require ligation & division

Allows enlargement of isthmic hypoplasis

Anastomosis is tension free

The posterior aortic wall & even hypoplastic aortic

arch grows after repair

Recoarctation [9%]

Aneurysm formation of aortic wall

opposite to patch

Described by robert gross in 1951using

aortic homograft

I960 , cooley & debakey used decron

graft

Indicated in patients > 10 yrs of age

,patients with associated aneurysm ,

patients with complex long segment

coarctation & patients with recurrent

coarctation.

Inability of prosthetic graft to grow with

child

Longer cross clamp time

Increase incidence of bleeding

Introduced by waldhausen & nahrwold in 1966

Indicated in infants

Operation is perform through left 4th ICS

The aota is clamped proximal to left subclavian and dital to coactation

Left subclavian is ligated distally near the origin of vertebral

artery & divided

The aorta is opened longitudinally & incision extended uptoleft subclavian

The subclavian flap is folded onto the aorta

Techniques is simple

Short cross clamp time

Avoidence of prosthetic matarial

Easy hemostatic controll

Increase anastomotic growth due to use

of autologous flap

Left arch ischemia due to ligation of left

subclavian

Poor growth & function of left upper limb

Aneurysm formation

Recoarctation[ 13%]

Given by Amato in1966

Perform by left thoracotomy or median sternotomy

Indicated in coarctation with hypoplastic distal transverse

arch

Adequate mobilzation of descending aorta, first two ot three

intercostal vessels are ligated & divided, arched vessels are

looped, clamp is placed between innominate & left carotid ,

ductal tissue excised, the coarctation segment is also excised & incision is made in transverse arch upto proximal clamp &

the two segment of aorta anastomosed

Mortality is 2% & recoarctation is 4%

Low rate of recoarctation

Avoidance of left arm ischemia & growth disorder

It addresses & corrects hypoplasia of transverse arch

Avoid prosthetic material

Limits the potential for aneurysm formation

Preseves normal vascular anatomy

It is the currently procedure of choice for

infants < 1 yr of age & in many children

also.

Described by elliott

Indicated in transverse arch hypoplasis

Clamps are placed proximal to left

carotid also involving some part of rihght

innominate artery

Allows extension of arch incision more

proximal than extende E to E

anastomosis

Described by sos in 1979 In patients with

neonatal coarctation

Indications

1] patients with major systemic illness that

increase the risk of surgery

2] older patients with mild discrete

coarctation with poor collateral

formation

3] for dilataion of recurrent coarctation

Formation of aneurysm near dilatation

site

Residual gradient > 20 mm hg

Aortic rupture with stents

In stent stenosis particularly in younger &

low birth weight children [31%]

Two stage response

First response is due to release of strech

on baroreceptor on carotid bodies after

removal of obstruction , it subsides within

24 hrs and it is due to increased

sympathetic activities

Second response is due to elevated level

of renin angiotensin, it appears within 48-

72 hrs of first response

1] mesenteric arterities & ischemia – child

develop abdominal pain tenderness

distension , GI bleeding requiring

laprotomy

Keep the patient NPO for 32-48 hrs

In immediate postoperative period

esmolol & nicardipine can be used to

titrate B.P.

ACE inhibitors can be used for second

phase response

Preoperative administration of

propranolol is quite useful in blunting

sympathetic response & managing

postoperative hypertension

There is a tendency of persistence of

hypertension even after repair of

coarctation which is proportionate to

age of patient

Described by hufnagel & gross in animals

Bing described paraplegia in humans after coarctation repair

in 1948

Incidence is 0.4%- 1.5%

The incidence is correlated with length of cross clamp time [>

49 min] & presence of abberent origin of right subclavian

below coarctation

Management of aortic pressure is crucial

SSEP are a possible method to assess reversible spinal cord

ischemia

Both true & false aneurysms can form as

a complication of coarctation repair

Risk factor for aneurysm formation

1] patch aortoplasty at advance age

2] operation on recoarctation

3]use of decron as compare of PTFE

patch

Risk factor for recoarctation:

1] age < 2months

2] weight < 2 kg

3] residual ductal tissue

4] use of silk sutures for anastomosis

Postoperative arm to leg peak systolic

pressure gradient of > 20 mmhg

acrossed repaired area

Simultaneous arm & leg pressure

measurement are best way to exclude

posssibilty of residual obstruction

Physical examination coupled with MRI

angiography is most accurate.

Resection & E TO E anastomosis have high recoarctation rate { 19%} followed by flap aortoplasty {13%}

Resection with extended E TO E anastomosis have lowest recoarctationrate{6%}

Treatment is balloon dilatation , if not successful reoperation is considered, reoperation is difficult owing to dense scarring & adhesions.

For patients with long segment

coarctation, very dense adhesions or

those requiring cardiac operations,

jacobs & coworker suggested bypass

graft from ascending to descending

aorta through combined thoracotomy &

median sternotomy approach

Kenter also reports extra anatomic

bypass grafts.

1. CoA proximal to left subclavian artery* 1% of all COA

* reverse subclavian flap* abdominal CoA : 0.5 ~ 2%

2. Mild or moderate coarctation* degenerative change prone to occur

3. Prevention of paraplegia* Collateral circulation, hypothermia(< 45min at 33 deg C)

* Descending aortic pressure under 50mmHg after clamp

4. Recurrent coarctationIncreased mortality and morbidity

5. CoA with VSD or other anomaliesIncreased mortality and morbidity

Echocardiography is primary diagnostic

tool

CT & MR angiography is very useful

specially to delineate the anatomy of

transeverse arch

Coarctation should be repaired at the

time of diagnosis to prevent late

hypertension

Resection & extended E TO E

anastomosis is treatment of choice for

infants , neonates & young children

Interposition graft placement is indicated

in older children & adults

Balloon dilatation is initial procedure of

choice for recoarctation if unsuccessful

reoperation with patch aortoplasty or

graft interposition is recommended.