Download Coarctation of Aorta

Coarctation of Aorta
Seoul National University Hospital
Department of Thoracic & Cardiovascular Surgery
Coarctation of Aorta
1. Definition
A congenital narrowing of upper descending thoracic aorta
adjacent to the site of attachment of ductus arteriosus
2. History
Morgagni
Bonnett
Crafoord
Vorsschulte
:
:
:
:
1st description in 1760
postductal & preductal type in 1903
1st coarctation repair in 1944
prosthetic onlay graft or vertical incision
and transverse closure in 1957
Waldhausen : subclavian patch aortoplasty in 1966
Coarctation of Aorta
Developmental factor
1. Underdevelopment or hypoplasia of aortic
arch or isthmus
Definition of hypoplasia
* Proximal arch : 60% of ascending aorta
* Distal arch
: 50% of ascending aorta
* Isthmus
: 40% of ascending aorta
2. Presence of ectopic ductal tissue in the aorta
Aortic Arch Hypoplasia
Definition
• Hypoplastic arch has higher ratio of elastin lamellae to
vessel diameter & increase in collagen and decrease in
alpha-actin-positive cell that may hinder the ability of
arch to distend.
1. 50% reduction of terminal end of ascending aorta, sometimes,
because of small ascending aorta in coarctation, descending
thoracic aorta is compared.
2. Transverse arch diameter less than body weight in Kg plus 1
3. Z-value less than –2 or more
Coarctation of Aorta
Morphology
1. Localized stenosis
* More than 50% reduction in cross sectional area
* Shelf, projection, infolding of aortic media into the
lumen opposite the ductus arteriosus
* Usually intimal hypertrophy ( intimal veil ) extends
the shelf circumferentially and further narrows the
lumen (Rodbard)
2. Tubular hypoplasia
*
*
*
*
Severe with lesser narrowing
Proximal aortic & arterial wall
Distal aortic arch narrowing
Fetal flow pattern (Rudolph)
Coarctation of Aorta
Evolution
Coarctation of Aorta
Pathophysiology
• 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
Coarctation of Aorta
Associated pathology
1. Collateral circulation
* Inflow
: primary from branches of both subclavian arteries
. internal mammary artery . vertebral artery
. costocervical trunk
. thyrocervical trunk
* Outflow : into descending aorta, two pairs of intercostal arteries
2. Aneurysm formation of intercostal arteries
* 3rd, & 4th rib notching
* rare before 10 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
CoA
Localized
CoA
Tubular Hypoplasia
Distal arch
PDA
Coarctation of Aorta
Natural history
1. Incidence
* 5-8% of CHD (5 per 10000 live births)
* Isolated CoA (82% of total CoA) ; male:female = 2:1
CoA + VSD 11%, COA + other cardiac anomalies 7%
* Complex CoA ; no sex difference
2. 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 decades
4. Aortic rupture
: 2~3rd decade
5. Intracranial lesion
: subarachnoid hemorrhage(cong. Berry
aneurysm)
Collaterals
in CoA
Coarctation of Aorta
Clinical features & diagnosis
1. Infancy
1) Closure of ductus (7-10 days) produces severe obstruction
2) Ductus arteriosus remains patent - differential cyanosis
3) Associated intracardiac defect - more severe, early onset
4) Degree of collateral circulation
2. Childhood
* Asymptomatic without significant associated lesion
* Hypertension (90%)
* Cardiomegaly (33%)
* Rib notching (15%)
3. Adolescence and adult
* Hypertension ; very common * Valvar heart disease
* Heart failure at 30 years of age
4. Associated syndrome
* Turner syndrome (XO) : 2% * Von Recklinghausen’s D
* Noonan’s syndrome or congenital rubella
Coarctation of Aorta
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
Coarctation of Aorta
Techniques of operation
1. Subclavian flap aortoplasty
Neonate, infant and child up to 10 years
2. End-to-end anastomosis
Preferred in any age group
* Extended end-to-end anastomosis
* Radically extended end-to-end anastomosis
3. Patch angioplasty or graft replacement
Prevention of Recoarctation
Ideal operative procedure
• Successfully address transverse arch hypoplasia (if
present),
• Resection of all ductal tissue, and
• Prevention of residual circumferential scarring at the
aortic anastomotic sit.
Factors
• Younger age at operation
• Presence of aortic arch hypoplasia remain risk factors
for recoarctation
Regional Cerebral Perfusion
Technique
• We begin full-flow CPB at a calculated baseline of 150
mL · kg–1 · min–1 and, after snare placement on the
proximal brachiocephalic vessels, initiate RLFP by
reducing pump flow to 50% of baseline.
• We make further adjustments such that baseline
cerebral blood flow velocity as measured by
transcranial Doppler and cerebral oximetrics as
measured by NIRS are optimally maintained.
• RLFP provides consistent cerebral circulatory support
and that this support is bilateral, despite being applied
to the inominate artery.
Pediatric Cardiac Surgery
Neurologic complications
• Incidence of 2.3% for overt clinical presentation & up
to 60% when sensitive magnetic resonance imaging is
applied in heart surgery of infants & children.
• In control of the arch proximal to the left carotid artery,
during COA surgery, this assumes that collateral blood
flow and completeness of the circle of Willis allows for a
favorable and even distribution of cerebral blood flow.
• But patients undergoing coarctation repair, proximal
occlusion of the aortic arch results in transient but
significant impairment in contralateral cerebral oxygen
balance
Blood Supply to Spinal Cord
The most important blood supply to spinal cord comes from
spinal artery, a minor supply is from Adamkiewicz artery
CoA
Exposure
CoA
LSCA flap
CoA Patch Augmentation
CoA Subclavian Artery Flap
CoA End-to-End Anastomosis
CoA
Extended end-to-end Anastomosis
Coactation of Aorta
Resection and Anastomosis
Coactation of Aorta
Resection & Extended end-to-end Anastomosis
Coarctation of Aorta
End-to-Side Anastomosis
Coarctation of Aorta
Enlargement of VSD, Resection of Conal Septum
CoA + VSD, One-stage Repair
CoA + VSD, One-stage Repair
Coarctation of Aorta
End-to-Side Anastomosis
Opening of Resected Segment
Coactation of Aorta
 Operative results
•
Hospital mortality
Causes of early death are
acute and chronic cardiac failure or severe
pulmonary insufficiency
•
Incremental risk factor for death
1) Older age
2) Hypoplastic left heart class
3) Techniques of operation
Coactation of Aorta
 Operative results
•
Mobidity
1) Paraplegia (0.2 ~ 1.5%)
2) Hypertension and abdominal pain
3) Persistent or recurrent coarctation
- more than 20mmHg
- high incidence in young
4) Upper body hypertension without resting gradient
- increased vascular activity in the forearm
- age at operation is risk factor
5) Late aneurysm formation
- higher in onlay patch technique
6) Valvular disease
7) Congestive heart failure with hypertension
8) Bacterial endocarditis
Coactation of Aorta
Special features of postoperative care
1. Systemic arterial hypertension
Usually, but infant or young child doesn’t
need to be treated.
2. Abdominal pain
Usually mild abdominal discomfort for a few days,
and prominent in 5 - 10%.
Control hypertension, nasogastric decompression,
IV maintain
3. Chylothorax
5%
Coactation of Aorta Repair
Postoperative hypertension
• Sealy
Altered baroreceptor response with increased
excretion of epinephrine or norepinephrine
• Rocchin
Sympathetic nervous system in early phase,
and renin-angiotensin system in late phase
Coactation of Aorta Repair
Paraplegia
1.
2.
3.
4.
5.
6.
7.
Duration of spinal cord ischemia
Duration of intercostal artery ischemia
Intraoperative proximal hypotension
Postoperative hypotension
Hyperthermia during operation
Anastomosis with tension
Acidosis in the perioperative periods
Coactation of Aorta
Special situation & controversies
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 coarctation
Increased mortality and morbidity
5. CoA with VSD or other anomalies
Increased mortality and morbidity
Coactation of Aorta
Balloon dilatation
• The role of balloon dilatation is controversial because of
early restenosis, the need for multiple interventions,
potential limb ischemia, and the increased risk of
aneurysm formation
• The mechanism for early restenosis in neonates may
be related to multiple factors including ductal tissue
constriction or recoil, isthmus hypoplasia, intimal
hyperplasia as a result of smooth muscle cell
proliferation, and matrix protein production with
arterial remodeling are involved in restenosis