Aortic Coarctation Flashcards
(51 cards)
What is “true” coarctation of the aorta?
A distinct, shelf-like thickening or infolding of the aortic media into the lumen of the aorta. It is distinct from hypoplasia of the aortic isthmus.
What is aortic hypoplasia?
Defined as a narrowed diameter of an aortic segment with a normal aortic media. This is distinct from true aortic coarctation which involves a thickened or folded aortic media.
What is an atretic aortic arch?
Refers to two patent ends with an interposed ligamentous strand.
What is almost always associated with an atretic aortic arch?
VSD (and the patent ductus arteriosus provides blood flow to the distal aorta.
What is the life expectancy of someone with uncorrected coarctation of the aorta?
30 years
What is the male to female ratio of aortic coarctation?
males:females = 3:2
What is aortic coarctation syndrome?
Coarctation plus hypoplasia of the aortic isthmus and intracardiac defects.
What is the definition of aortic isthmus hypoplasia?
When the isthmus is less than 40% of the diameter of the ascending aorta.
What is the definition of proximal transverse aortic arch hypoplasia?
When the diameter is 60% of the ascending aorta.
What is the definition of hypoplasia of the distal transverse aortic arch?
When the diameter is 50% of the ascending aorta.
What are the two historical classifications of aortic coarctation?
Adult (post-ductal) which was actually a discrete juxtaductal narrowing, and Infantile (preductal) which involved a more diffuse narrowing of an aortic segment in addition to the juxtaductal narrowing.
What is the modern classification system of aortic coarctation?
It involves three categories:
1) isolated coarctation
2) coarctation with VSD
3) coarctation with complex intracardiac anomaly
What are the cardiovascular anomalies COMMONLY associated with coarctation of the aorta?
VSD Bicuspid Ao valve Various mitral anomalies PDA Ao hypoplasia
What is Shone’s syndrome?
It is the combination of 1) Ao Coarctation, 2) supravalvular mitral stenosis, 3) parachute mitral valve, 4) sub-aortic stenosis
What is the association of low pulmonary blood flow cardiac lesions/syndromes with coarctation of the aorta?
They are rarely associated with coarctation of the aorta.
What life-threatening extra-cardiac, extra-aortic anomaly is associated with aortic coarctation?
Intracranial aneurysms
Name three chromosomal abnormalities in which aortic coarctation is relatively common.
Trisomy 13
Trisomy 18
Turner’s
What is one theory that explains why aortic coarctation occurs so close to the ductus arteriosus?
Some investigators suggest that ductal tissue spreads into the aorta and subsequently causes constriction after birth. Normally, ductal tissue invades up to 1/3 of the aorta’s circumference, but in local coarctation sometimes completely encircles the aortic lumen.
What is thought to be the cause of aortic coarctation in Turner’s syndrome?
Lymphatic obstruction resulting in distended thoracic ducts that compress the ascending aorta, alter intracardiac blood flow, and cause neck webbing.
In Turner’s syndrome, what common external physical finding is associated with coarctation of the aorta?
Neck webbing. Turner’s patients with neck webbing are eight times more likely to have coarctation of the aorta than those without neck webbing. NOTE: other syndromes with webbed necks such as Noonan’s and fetal hydantoin do not demonstrate this association.
What are common physical exam findings in an infant < 3 months old with aortic coarctation?
Ejection murmur along the left sternal border and in the left subscapular area.
Prominent precordial impulse often with systolic thrill.
Hepatomegaly and gallop rhythm if CHF is present.
Commonly femoral pulses are diminished.
Describe the pressures measured in the lower extremities as compared to the upper extremities in patients with aortic coarctation.
Classically, there is a large gradient between the two measurements in which the upper extremities have a markedly higher blood pressure than the lower; however, in the setting of a PDA the pressures in the lower extremities may be equal to or even higher than those in the upper.
What anatomic and physiologic findings can explain the absence of a systolic pressure gradient in patient with CoA?
1) The RV may provide flow to the lower body via a PDA
2) LV function may be so poor that systemic hypotension makes it impossible to detect a gradient
3) Rarely, the right subclavian artery has an aberrant origin distal to the coarctation.
If a patient with CoA lacks a systemic gradient between upper and lower extremities, how might pulse oximetry reveal the reason why?
If the patient has a PDA and relies on the RV for systemic blood flow, there may be a differential cyanosis with lower SpO2 recorded from the toe than the preductal hand.
