Coarctation of aorta
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Transcript of Coarctation of aorta
COARCTATION OF AORTA
Dr. VIKAS
Deptt. Of ctvs, pgimer, chandigarh
COARCTATION OF AORTA
EMBRYOLOGY NOMENCLATURE PATHOPHYSIOLOGY NATURAL HISTORY CLINICAL FEATURES
NOMENCLATURE Coarctatus (Latin) – contracted tightened &
pressed together
Haemodynamically significant congenital narrowing of upper descending thoracic aorta adjacent to ductus arteriosus
Interrupted aortic arch - Lumen is atretic short distance seperates aortic ends .
Primary/ pure/ isolated CoA ± PDA without other associated anomalies
NOMENCLATURE (contd)
Hypoplasia of proximal transverse aortic arch is a diameter less than 60% of the ascending aorta
Hypoplasia of the distal aortic arch (between the left common carotid artery and the left subclavian artery) is a diameter < 50% of the ascending aorta.
Isthmic hypoplasia is diameter < 40% of the ascending aorta.
Hypoplasia of the distal arch requiring reconstruction is considered to be present if the diameter of the aortic arch (in mm) is less than 1 plus the infant’s weight in kgs.
History
1760 Johann Freidrich Meckel- extra ordinary dilatation of heart due to narrow aortic conduit.
1760 Morgagni- 1st description at autopsy
1790 Paris described pathologic features
Van Praagh –Juxtaductal (reflects different age of presentation of patients)
1928-1946 Reifenstein, Levine, Gross natural history (though did not appreciate that CoA is a frequent cause of death in infancy)
Abbot’s artery
Dr. Maude Elizabeth Seymour Abbott
first and largest post-mortem series in 1928
findings from all 200 previously documented cases over the age of 2 years, dating from the first report of aortic coarctation by Paris in 1791
Alfred Blalock
Alfred Blalock and Edward Park at Johns Hopkins, proposed the first surgical repair in 1944, describing a bypass from the left subclavian artery to the aorta to circumvent the area of narrowing.
Clarence Crafoord Crafoord and Nylin at
Karolinska Institute, (Stockholm, Sweden) performed the first resection with end-to-end reanastomosis in 1944.
19 October 1944, The patient was a 14 year-old boy. 32 years later, the patient was symptom-free with no pressure gradient across the repair
Robert Edward Gross
Gross (1948) used homografts to replace the narrowed segments of aorta.
Maurice Campbell
Natural history of coarctation of the aorta. Br Heart J 1970; 32:633–40
EMBRYOLOGY
Ductus tissue theory: skoda proposed abnormal extension of contractile
ductal tissue into aorta
contraction and fibrosis at ductal closure lead to aortic constriction and primary coarctation .
Haemodynamic theory: reduced flow across aortic isthmus during fetal life
lead to poor development of istmus “no flow no grow’
Turner syndrome XO: Fetal lymphatic obstruction distended thoracic duct compresses fetal descending thoracic aorta development of CoA
Gridlock mutant gene - related to early disturbance in vessel formation due to recessive mutant gene (Shelf in fetus with CoA)
CLASSIFICATION 1903 Bonnett classified into Adult(Post ductal) and
infantile(Preductal) Amato et al.
I - Primary CoA
II- CoA with isthmic hypoplasia III- CoA with tubular hypoplasia (isthmus and
segment between left common carotid artery & left subclavian arteries)
Subtypes 1. with VSD 2. with other major cardiac defects
Surgical classification:
I - Isolated CoA II - CoA with VSDIII - CoA with complex intra-cardiac anomaly
Types of coarctation
Morphological Features
Discrete CoA Adult / Juxtaductal/ Postductal In older chidren and adults Associated cardiac lesions are rare Well developed collateral circulation rare < 5 yrs of age. External - sharp indentation at CoA site Internal - obstructing diaphragm/ shelf 1. Infolding of Aortic media 2. Ridge formed by intimal hyperplasia 3. Present opposite to the site of ductus due to
reorientation of the angle formed by the ductus and the aorta
Changes Post stenotic dilatation Collateral formation Degenarative changes
Tubular hypoplasia Preductal/infantile Presents in infancy Associated with major cardiac anomalies collateral circulation/seconadary changes are
rare Externally continuity of PDA and DTA is seen
Coarctation of Aorta
COLLATERAL CIRCULATION
Seen mostly in isolated coarctation
Usually symmetrical on both sides
Inflow is from subclavian artery branches
Outflow into upper DTA
Mostly third and fourth intercoastals
Collateral formation in Coarctation of Aorta
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 (First two post I/C art which arise from Sup I/C art, br of Costocervical trunk, do not participate)
2. Arteria Aberrans
Around the Scapula 1. Transverse cervical & transverse scapular art from thyrocervical trunk of subclavian art
2. Suprascapular art from Subclavian art3. 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 Aorta2. 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 art2. Post spinal art from Post inf cerebellar
art or vertebral art
1. Radicular art from post div of post I/C and lumbar art
Arteria Aberrans
Branches from right side of descending thoracic aorta near the origin of right bronchial artery
Represents the remains of right dorsal aorta
Passes behind the trachea and oesophagus and may anastomose with the right Sup I/C art
Occassionally is enlarged to form 1st part of right Subclavian artery
Abbott’s artery
Arise anywhere on the posterior wall of aortic arch or back of the subclavian artery within a radius of 2cm from the origin of subclavian artery
Proceeds cranially and turns behind carotid artery and aortic arch
Represent evanescent remnant of fifth arch
Described By Maude Abbott
Rib notching seen in older patients
uncommon below 5 years
Seen in third to ninth rib posteriorly
Erosion of inferior surfaces of posterior ribs
Associated AnomaliesCardiac anomalies
1. PDA present in all cases of preductal or infantile type of CoA
2. PFO
3. Left sided obstructive lesions (aortic stenosis or atresia, bicuspid aortic valve (46%), subaortic stenosis, Shone’s syndrome)
4. Lesions with abnormal interventricular or great vessel communications (VSD either in isolation (11%) or in combination with transposition; and aortopulmonary window)
Coarctation of the Aorta with VSD
VSD in 40% present in the neonatal period :
increased L-R shunting (VSD) results in CCF.
no specific type
Coarctation of the Aorta with MV Abnormalities
seen in 25% 2% have severe abnormalities and 10%
of patients also have MR. Incidence of MS higher with VSD and
coarctation as compared with coarctation alone.
MS:parachute mitral valve or hypoplasia of the mitral valve ring or supravalvar ring.
Coarctation of the Aorta with AS
21% of patients with coarctation have aortic valve disease but only 2% are severe enough requiring surgery. 5% of all critically ill infants with coarctation also have aortic stenosis.
valvar or subvalvar
decreased cardiac output with poor pulses in all extremities masking upper and lower extremity pulse difference.
Coarctation of Aorta is NOT ASSOCIATED with TOF Congenital Pulmonary Stenosis Pulmonary Atresia Tricuspid Atresia Rt Aortic Arch
Associated Anomalies
Extracardiac vascular anomalies: Intracranial aneurysms variation in Brachiocephalic art anatomy left subclavian art arise at the site of stenosis Aberrant right subclavian art arise distal to
CoA (Subclavian steal syndrome due to reverse flow of vertebral art) or retroesophageal anomalous right subclavian artery
Dissecting aortic aneurysm Vascular rings—double aortic arch
Associated Syndromes
Turner’s syndrome
Von Recklinghausen’s disease
Noonan syndrome
Congenital rubella
Pathophysiology
1. Degree of obstruction
2. Type of Coarctation (preductal versus postductal)
3. Rapidity of development of obstruction
4. Status of ductus arteriosus
5. State of collateral development
6. Presence of associated intra-cardiac lesions.
Coarctation with IVS & closure of PDA
↑ ↑ SVR ↑ Asc Ao pr
PDA closure ↓ PBF
↓ Desc Ao Pr
↑ LV pr ↑LA Pr
↑L R shunt (ASD)
↓ LV vol load
Effect of Prostaglandin E1
Relaxes the ductus smooth muscle that has extended into the aortic wall
Maintains patency of ductus arteriosus
Effective within 7 – 10 days
Therefore it is required for pre-operative stabilization of patients with preductal coarctation who are duct dependent circulation
Effect of Oxygen
100% Oxygen
Early PDA closure
Increases Coarctation gradient
Coarctation with IVS & collateral formation
Collateral formation
Asc Ao requires less pr to maintain distal flow
↓ LV afterload
CCF improves
Coarctation with small VSD
Insignificant effect on infants ↑ LV pressure large shunt Leading to moderate PAH
Coarctation with large VSD
Large LR shunt when obstruction develops (↑ afterload)
If obstruction is acute ↓ CO, failure ↑ PA pressure very early pulm vascular
disease
Complications of longstanding CoA
Post-stenotic dilatation of upper descending thoracic aorta
Collateral formation which may become aneurysmal
Degenerative changes (saccular aneurysm formation, intimal erosion with dissection, marked disruption of elastic tissue and mycotic aneurysm)
Hypertension
Mycotic aneurysm and bacterial endocarditis in CoA
Dissecting aneurysm in complicating Coarctation of Aorta
ANEURYSM COLLATERALEnlarged tortuous third ,fourth intercoastals
Mostly saccular
Rare before 10 yrs
Prevelance 10% at end of second decade,20% by third decade
HT with CoA
Etiology Mechanical obstruction Reactivity of arteriolar resistance vessels ↓ compliance of Aortic wall Resetting of baroreceptor reflex plasma renin activity
Natural History
Incidence 50: 1lakh live births. Common in males.5-7% of congenital heart disease80% of these are isolated CoA ± PDANatural history of untreated isolated CoA 1st month:10% - acute CHF 1st year: 20% - CHF 1-4 yrs: 10% - chronic CHFThus 50% die within 10 yrs of life14-20yrs of age: 20% will die d/t Bacterial
endocarditis, aortic rupture or intracranial hemorrhage20-50 yrs of age: 20% d/t heart failure secondary to
HT or valvular heart disease
Natural History (Campbell 1970)
Studied survival of patients > 2yrs of age
20yrs of age: 25% will die
32yrs of age: 50% will die
46 yrs of age: 75% will die
58yrs of age: 90% will die
Hazard function
Very high peak of hazard during 1st month of life which falls rapidly, and by the end of 1year, it reaches constant hazard phase. That continues till 30 yrs of age, & then it starts rising
Natural History-Aortic rupture
Common in 2 & 3rd decade Involves usually ascending aorta leading to
haemopericardium with temponade Less often occurs at the site of post-stenotic
dilatation Are probably true dissecting aneurysm
Natural History- Coarctation with Intracranial lesions (Reifenstein, Abbott)
Death around 28-30 yrs Subarachnoid hemorrhage from rupture of
congenital berry aneurysm on the circle of willis arteries -cause of rupture may be associated HT,
CVA - atherosclerosis - emboli in the presence of infective
endocarditis
Natural History - CoA with VSD
Presentation is earlier than in patients with isolated VSD
Most of these babies die within few months without surgical treatment, in case the VSD does not diminish in size
Pseudo-coarctation Kinking of aorta in vicinity
of ductus Elongated tortuous, dilated
distal to Aortic arch and Prox. descending aorta
Absence of narrowing of Aortic lumen
Absence of gradient Abdominal CoA
In prox and distal to renal art
With renal artery stenosis
Clinical Presentation
Neonates & Infants– CCF as PDA closes– sudden CCF,shock,multi organ
failure,renal failure & necrotising enterocolitis,DeathChildhood—Usually asymtomatic,
HypertentionAdolescence & adult life--
--Asymtomatic--reduced femoral pulse
--murmur, hypertention--
headache,epitaxis,claudication --rarely with CCF, dissection,intracranial hemorrhage
--steal syndrome-during exercise
CLINICAL FEATURES
Newborn – no evidence of CoA CHF – early infancy(esp. at 1-2weeks) & 4th
decade CVA – 2nd – 3rd decade IE / Endarteritis – 2nd – 4th decade Rupture / Dissection – 3rd – 4th decade HT & CAD
CVS examination
Pulse – brachio-femoral delay left radial pulse weak – LSCA stenosis right radial pulse weak – aberrant
RSCA Subclavian steal syndrome Differential cyanosis (PDA with Right to Left shunt) Coarctation with VSD- no cyanosis as Left to
Right shunt
CVS examination
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
Auscultation
S1 loud mitral component S2 normal splitting with delayed loud A2 Gallop rhythm
Murmurs
Systolic 1. Collateral – delayed onset crescendo-
decrescendo in ant thorax, right infraclavicular, left sternal and suprasternal.
2. Coarctation – soft localized posteriorly3. Functional – ESM of BAV
Diagnostic methods
Two dimensional echocardiography can visualize coarctation in neonates and small infants and is usually the definitive study
Associated anomalies, severity
After infancy, helpful but usually not definitive
Diagnostic methods (ctd)
Cardiac catheterization and aortography
To confirm the diagnosis in older patients and in doubtful cases during infancy.
Define the anatomy, location and severity
Hypoplasia of arch Ductus Collaterals Associated lesions Pulmonary vasculature
Cardiac catheterization and aortography (ctd.) Resting gradient of >20 mm Hg is significant Falsely low gradient in:
1. Large ductus
2. well developed collaterals
3. low cardiac output/ poorly contracting LV
4. Multiple left sided obstructive lesions
Aortography
Decrease in luminal diameter approaching 50% significant.
Also reveal any hypoplasia of arch/isthmus Arrangement of aortic branches Degree of Collateral circulation aneurysm
Diagnostic methods (ctd)
CT/MRI increasingly being used in patients outside of infancy instead of cardiac catheterization
Also indicated if age > 20 years because of higher prevalence of aneurysm
Unequal arm pressures (anomalous right subclavian or involvement of left subclavian artery origin), absence of palpable collaterals and rib notching
( poorly developed collaterals)
Medical therapy
Optimization of hemodynamics before surgery with inotropic support and diuretic therapy.
Prostaglandin E1 - promotes ductal patency and improves perfusion of the descending aorta, renal and mesenteric beds.
Relaxation of the aortic end without actually opening the entire ductal lumen
Starting dose of 0.05mcg/kg/min increased to 0.1-0.15mcg/kg/min
May cause apnea or hypotension
Medical therapy (ctd.)
correction of the severe acidosis and oliguria, hypothermia, hypoglycemia and anemia.
If required intubation and mechanical ventilation.
If associated large VSD, keeping PCO2 to 45 to 50 mm Hg, thus raising the PVR and increasing the ductal flow to the lower body.
converting an otherwise emergent procedure into an elective one .
THANK YOU & to be contd