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Coarctation of Aorta

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Underdevelopment or hypoplasia of aortic arch or isthmus Definition of hypoplasia * Proximal arch : ... Aneurysm formation of intercostal arteries * 3rd, ... – PowerPoint PPT presentation

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Title: Coarctation of Aorta


1
Coarctation of Aorta
2
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 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

3
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

4
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

5
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)

6
Coarctation of Aorta
  • Evolution

7
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

8
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

9
CoA Localized
10
CoA Tubular Hypoplasia
Distal arch
PDA
11
Coarctation of Aorta
  • Natural history
  • 1. Incidence
  • 5-8 of CHD (5 per 10000 live
    births)
  • Isolated CoA (82 of total CoA)
    malefemale 21
  • 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 23rd decade
  • 5. Intracranial lesion subarachnoid
    hemorrhage(cong. Berry

  • aneurysm)

12
Collaterals in CoA
13
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
    Recklinghausens D
  • Noonans syndrome or congenital rubella

14
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

15
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

16
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

17
Regional Cerebral Perfusion
  • Technique
  • We begin full-flow CPB at a calculated baseline
    of 150 mL kg1 min1 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.

18
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

19
Blood Supply to Spinal Cord
The most important blood supply to spinal cord
comes from spinal artery, a minor
supply is from Adamkiewicz artery
20
CoA Exposure
21
CoA LSCA flap
22
CoA Patch Augmentation
23
CoA Subclavian Artery Flap
24
CoA End-to-End Anastomosis
25
CoA Extended end-to-end Anastomosis
26
Coactation of Aorta Resection and Anastomosis
27
Coactation of Aorta Resection Extended
end-to-end Anastomosis
28
Coarctation of Aorta End-to-Side Anastomosis
29
Coarctation of Aorta Enlargement of VSD,
Resection of Conal Septum
30
CoA VSD, One-stage Repair
31
CoA VSD, One-stage Repair
32
Coarctation of Aorta End-to-Side Anastomosis
Opening of Resected Segment
33
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

34
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

35
Coactation of Aorta
  • Special features of postoperative care
  • 1. Systemic arterial hypertension
  • Usually, but infant or young child doesnt
  • 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

36
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

37
Coactation of Aorta Repair
  • Paraplegia
  • 1. Duration of spinal cord ischemia
  • 2. Duration of intercostal artery ischemia
  • 3. Intraoperative proximal hypotension
  • 4. Postoperative hypotension
  • 5. Hyperthermia during operation
  • 6. Anastomosis with tension
  • 7. Acidosis in the perioperative periods

38
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(lt 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

39
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
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