Aortic coarctation physical examination

In the majority of patients with coarctation, the constriction is located just distal to the subclavian artery. Due to the presence of constriction at isthmus (proximal to the descencing aorta) the pressure of blood proximal to constriction is high whereas the pressure distal to constriction is low. This leads to hypertension in the upper extremities (supplied by subclavian) and hypotension in lower extremities. The difference is usually in systolic blood pressure whereas the diastolic blood pressures are typically similar. Similarly, the pulses in upper extremities are bounding whereas the femoral pulses are often diminished (brachial-femoral delay). There are 3 potential sources of a murmur: multiple arterial collateral (continuous murmur), an associated bicuspid aortic valve (systolic ejection click), and the coarctation itself which can be heard over the left infraclavicular area and under scapula. Murmurs due to associated cardiac abnormalities such as VSD or aortic valve stenosis, may also be detected. Neonates may present with discrepancies in blood pressure and pulses between the limbs, differential cyanosis or reversed differential cyanosis (depending on associated lesions), murmur, congestive heart failure, and shock. Older children and adolescent may be referred due to agitated behavior, headache, vision problem, and hypertension.

• Tachypnea
• Labored breathing (prominent accessory muscles)

• In human anatomy, the subclavian arteries are two major arteries of the upper thorax. They receive blood from the arch of the aorta. The left subclavian artery supplies blood to the left arm and the right subclavian artery supplies blood to the right arm, with some branches supplying the head and thorax.
• Abnormalities in blood pressure and pulses are hallmark of diagnosis in coarctation of aorta. The physical finding depends on the severity and location of constriction relative to the the origin of subclavian artery:
  • Tachycardia
  • Left subclavian proximal to coarctation: hypertension and normal pulses in both arms and hypotension and diminished pulses in lower extremities (differential hypertension). Synchronous radial pulses, but radial-femoral delay will be present under palpation in either arm. This may be appreciated best by simultaneous arm and leg pulse palpation.
  • Left subclavian distal to coarctation: hypotension and diminished pulses in left arm and lower extremities. Asynchronous radial pulses will be detected in the right and left arms. A brachial-femoral delay between the right arm and the femoral artery may be apparent, while no such delay may be observed with left arm brachial-femoral palpation.
  • Both right and left subclavian artery originate below coarctation: blood pressure and pulses decreased in all four extremities.
  • In mild cases though the pulses are palpable in all for extremities a brachial-femoral delay can be appreciated.
  • Femoral pulses are often diminished in strength. Exercise exacerbates this gradient.

There may be webbing of the neck in patients with Turner syndrome, 35% of whom have aortic coarctation.

• Prominent suprasternal notch pulsation.
• A suprasternal or precordial thrill suggesting associated aortic valve stenosis.
• Abdominal bruit in case of an abdominal coarctation.

• The S2 is loud secondary to hypertension.
• S4 may be present secondary to LVH.
• A prominent P2 may be present if there is associated pulmonary hypertension.

• There are 3 potential sources of a murmur:
  • Multiple arterial collateral (via the internal thoracic, intercostal, subclavian, and scapular arteries) producing a continuous murmur
  • An associated bicuspid aortic valve producing a systolic ejection click.
  • The coarctation itself producing a short midsystolic murmur extending beyond the second heart sound which can be heard over the left infraclavicular area and under scapula.
• Murmurs due to associated cardiac abnormalities such as VSD or aortic valve stenosis, may also be detected.

• Congestive heart failure: may present as tachycardia, tachypnea, ankle edema, anasarca, jugular vein distention, pleural effusion with dullness to percussion at the bases, rales, hepatomegaly, ascites, S3 gallop rhythm, displaced point of maximum impulse (PMI) consistent with an enlarged left ventricle.
• Infective endocarditis: may present with fever with rigors, petechiae, splinter hemorrhages, osler’s nodes, janeway lesions, conjunctival hemorrhage, roth’s spots in the retina, heart murmur(s), signs of heart failure such as rales, splenomegaly, septic emboli, seizures, intracranial hemorrhage and brain abscess.
• Right-sided cardiac obstructive lesions, such as pulmonary stenosis, pulmonary atresia, or tetralogy of Fallot, are observed rarely.

• Differential cyanosis (pink upper extremities with cyanotic lower extremities) may occur when right-to-left shunt across a patent ductus arteriosus provides flow to the lower body.
• Reversed differential cyanosis (upper body cyanosis with normal lower-body oxygen) may occur with associated lesions like transposition of the great arteries, patent ductus arteriosus, and pulmonary hypertension (right-to-left shunt).
• Occasionally adults may have narrow hips and thin legs or have an undeveloped left arm (in those patients in which the coarctation compromises the origin of the subclavian artery).

• Intracranial hemorrhage (subarachnoid hemorrhage, intracerebral hemorrhage)
• The presentations of these intracranial hemorrhage may be headache, hypertension, seizures, meningism, decreased level of consciousness or coma, intraocular hemorrhage, extrocular muscle palsy.
  • This may be due to the increased association of intracranial aneurysm dilated collateral arteries in spinal cord.
  • The ususal age for presentation is 10-30 years.
  • Hypertension increases the chance for these hemorrhages but it has also been found associated in patients with normal blood pressure.
  • Treatment of choice for most aneurysms is placement of a clip across the neck of the aneurysm thus retaining the parent artery yet obliterating blood flow to the aneurysm.

• Neonates may present with discrepancies in blood pressure and pulses between the limbs, differential cyanosis or reversed differential cyanosis (depending on associated lesions), murmur, congestive heart failure, and shock.
• The newborn infant may remain asymptomatic if the PDA is patent or if the coarctation is not severe.
• Severe coarctation of the aorta and a large PDA with a right-to-left shunt into the descending thoracic aorta in a neonate can present as differential cyanosis.

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• Older children and adolescent may be referred due to agitated behavior, headache, and vision problem. Careful measurement of blood pressure and pulses in all four limb is required.
• A pressure difference of more than 20 mm Hg in favor of the arms may be considered evidence of coarctation of the aorta.
• Abnormalities of blood vessels in the retina.
• Murmur and pulsation can be appreciated.
• Conditions other than coarctation (eg, atherosclerotic disease, aortic dissection) can also cause unequal pulses and blood pressures, thus these conditions should also be considered when pulse and blood pressure discrepancies are found.

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