Coarctation of the Aorta

Coarctation of the aorta usually occurs at the proximal thoracic aorta just beyond the left subclavian artery and just across from the opening of the ductus arteriosus. Coarctation rarely involves the abdominal aorta. Thus, in utero and before the patent ductus arteriosus (PDA) closes, much of the cardiac output bypasses the coarctation via the PDA. Coarctation may occur alone or with various other congenital anomalies (eg, bicuspid aortic valve Bicuspid Aortic Valve Bicuspid aortic valve is the presence of only two (rather than the normal three) valve cusps. Bicuspid aortic valve is the most common congenital cardiovascular abnormality. It is present in... read more , ventricular septal defect Ventricular Septal Defect (VSD) A ventricular septal defect (VSD) is an opening in the interventricular septum, causing a shunt between ventricles. Large defects result in a significant left-to-right shunt and cause dyspnea... read more , aortic stenosis Aortic Stenosis Aortic stenosis (AS) is narrowing of the aortic valve, obstructing blood flow from the left ventricle to the ascending aorta during systole. Causes include a congenital bicuspid valve, idiopathic... read more , patent ductus arteriosus Patent Ductus Arteriosus (PDA) Patent ductus arteriosus (PDA) is a persistence of the fetal connection (ductus arteriosus) between the aorta and pulmonary artery after birth. In the absence of other structural heart abnormalities... read more , mitral valve disorders Overview of Cardiac Valvular Disorders Any heart valve can become stenotic or insufficient (also termed regurgitant or incompetent), causing hemodynamic changes long before symptoms. Most often, valvular stenosis or insufficiency... read more , intracerebral aneurysms). The aneurysms associated with coarctation are usually saccular and are referred to as berry aneurysms.

Physiologic consequences involve 2 phenomena:

Pressure overload causes left ventricular hypertrophy and hypertension in the upper part of the body, including the brain.

Hypoperfusion affects the abdominal organs and lower extremities. Malperfusion of the intestine increases the risk of sepsis due to enteric organisms.

Ultimately, the pressure gradient increases collateral circulation to the abdomen and lower extremities via intercostal, internal mammary, scapular, and other arteries.

Untreated coarctation may result in left ventricular hypertrophy, heart failure Heart Failure (HF) Heart failure (HF) is a syndrome of ventricular dysfunction. Left ventricular (LV) failure causes shortness of breath and fatigue, and right ventricular (RV) failure causes peripheral and abdominal... read more , collateral vessel formation, bacterial endocarditis Infective Endocarditis Infective endocarditis is infection of the endocardium, usually with bacteria (commonly, streptococci or staphylococci) or fungi. It may cause fever, heart murmurs, petechiae, anemia, embolic... read more , intracranial hemorrhage Intracerebral Hemorrhage Intracerebral hemorrhage is focal bleeding from a blood vessel in the brain parenchyma. The cause is usually hypertension. Typical symptoms include focal neurologic deficits, often with abrupt... read more , hypertensive encephalopathy, and hypertensive cardiovascular disease during adulthood. Patients with untreated coarctation are at increased risk of aortic dissection Aortic Dissection Aortic dissection is the surging of blood through a tear in the aortic intima with separation of the intima and media and creation of a false lumen (channel). The intimal tear may be a primary... read more or rupture later in life or in association with pregnancy. The ascending aorta is the area most frequently involved in dissection or rupture. Current data suggest that this risk is less likely a direct consequence of the coarctation and more likely related to a bicuspid aortic valve Bicuspid Aortic Valve Bicuspid aortic valve is the presence of only two (rather than the normal three) valve cusps. Bicuspid aortic valve is the most common congenital cardiovascular abnormality. It is present in... read more and associated aortopathy.

If coarctation is significant, circulatory shock with renal insufficiency (oliguria or anuria) and metabolic acidosis Metabolic Acidosis Metabolic acidosis is primary reduction in bicarbonate (HCO3⁻), typically with compensatory reduction in carbon dioxide partial pressure (Pco2); pH may be markedly low or slightly... read more may develop within the first 7 to 10 days of life and may mimic findings of other systemic disorders such as sepsis. Infants with critical (severe) coarctation are likely to become acutely ill as soon as the ductus arteriosus constricts or closes.

Less severe coarctation may be asymptomatic during infancy. Subtle symptoms (eg, headache, chest pain, fatigue, and leg claudication during physical activities) may be present as children age. Upper-extremity hypertension is often present, but heart failure Heart failure Congenital heart disease is the most common congenital anomaly, occurring in almost 1% of live births ( 1). Among birth defects, congenital heart disease is the leading cause of infant mortality... read more rarely develops after the neonatal period. Rarely, in adulthood, intracerebral aneurysms rupture, resulting in subarachnoid or intracerebral hemorrhage.

Typical physical examination findings include strong pulses and hypertension in the upper extremities, diminished or delayed femoral pulses, and a blood pressure (BP) gradient, with low or unobtainable arterial BP in the lower extremities. Since the coarctation site is usually adjacent to the ostium of the left subclavian artery, the left arm pulse and blood pressure may also be diminished, but they are still greater than leg pulses or blood pressures.

A grade 2 to 3/6 ejection systolic murmur is often present at the upper left sternal border, left axilla, and sometimes most prominently in the left interscapular area (see table ). An apical systolic ejection sound (click) may be present if a bicuspid aortic valve Bicuspid Aortic Valve Bicuspid aortic valve is the presence of only two (rather than the normal three) valve cusps. Bicuspid aortic valve is the most common congenital cardiovascular abnormality. It is present in... read more is also present. Dilated intercostal collateral arteries may cause a continuous murmur in the intercostal spaces.

Affected females may have Turner syndrome Turner Syndrome In Turner syndrome, girls are born with one of their two X chromosomes partly or completely missing. Diagnosis is based on clinical findings and is confirmed by cytogenetic analysis. Treatment... read more .

Diagnosis is suggested by clinical examination (including BP measurement in all 4 extremities and comparing amplitude of brachial and femoral pulses), supported by chest x-ray and ECG, and established by 2-dimensional echocardiography with color flow and Doppler studies or, in older patients with a suboptimal echocardiographic window, with CT or MR angiography.

Chest x-ray shows coarctation as a “3” sign in the upper left mediastinal shadow. Heart size is normal unless heart failure supervenes. Dilated intercostal collateral arteries may erode the 3rd to 8th ribs, causing rib notching, but this radiographic sign is seldom seen before age 5 years.

ECG usually shows left ventricular hypertrophy but findings may be normal. Because the presence of a coarctation alters fetal circulation by shifting a higher proportion of flow through the right ventricle, neonates and infants with severe coarctation usually have right ventricular hypertrophy rather than left ventricular hypertrophy.

Symptomatic neonates are treated promptly. In infants with very mild coarctation and no signs of lower body hypoperfusion, the condition is monitored until definitive repair is done.

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