--- title: Coarctation of the aorta description: What coarctation of the aorta is, why it makes blood pressure higher in the arms than in the legs, how it shows in newborns, children and adults, how it is found and treated, and when urgent help is needed. type: disease aliases: - CoA sources: - tier: guideline org: minzdrav-rf title: Коарктация аорты year: 2023 url: https://cr.minzdrav.gov.ru/view-cr/754_1 - tier: guideline org: esc title: 2020 ESC Guidelines for the management of adult congenital heart disease year: 2020 doi: 10.1093/eurheartj/ehaa554 url: https://doi.org/10.1093/eurheartj/ehaa554 - tier: reference org: msd-manuals title: Coarctation of the Aorta year: 2023 url: https://www.msdmanuals.com/professional/pediatrics/congenital-cardiovascular-anomalies/coarctation-of-the-aorta sources_checked: 2026-10-12 review: null --- Coarctation of the aorta is a congenital narrowing of the aorta. It is usually found at the start of the descending thoracic aorta: just beyond the point where the left subclavian artery leaves the aorta, opposite the [ductus arteriosus](../patent-ductus-arteriosus/) (this segment is called the aortic isthmus). The narrowing can be short or long, in which case a whole segment of the aorta is narrow; in the most severe cases the aorta is completely closed off. It occurs in about 2–5 in 10,000 newborns and is twice as common in boys as in girls.

Normally the aortic isthmus, the segment just beyond the left subclavian artery, is not narrowed. Blood from the left ventricle flows freely both into the arteries to the head and arms and down the descending aorta to the abdominal organs and legs. Normally systolic blood pressure is lower in the arms than in the legs.

In coarctation the aorta is narrowed just beyond the left subclavian artery. Above the narrowing, in the arteries to the head and arms, blood pressure is raised and the wall of the left ventricle thickens; below the narrowing the abdominal organs and legs receive less blood.

After the procedure the narrowing is repaired: in surgery the narrowed segment is removed and the aorta is rejoined directly or with a graft, and through a catheter it is widened with a balloon or a stent. The doctor chooses the method. A small residual narrowing is possible. Even after successful treatment blood pressure can stay high and the narrowing can come back, so lifelong follow-up with a cardiologist is needed.

## Why it happens At the site of the narrowing, tissue from the ductus arteriosus extends into the wall of the aorta. Before birth, and until the duct closes, much of the blood can flow through it and bypass the narrowing. After birth this tissue changes, and the aorta at this point can gradually become narrower. This is why a baby with severe coarctation becomes acutely ill as soon as the duct narrows or closes. Because of the narrowing, pressure rises above it, in the vessels of the arms and head, and the left ventricle has to work against an extra load, so its wall thickens. Below the narrowing the abdominal organs and legs receive less blood. Over time blood starts to flow around the narrowing through small arteries that widen (collaterals), such as the arteries between the ribs. Coarctation can occur on its own or together with other features of the heart and vessels: a bicuspid aortic valve, a ventricular septal defect or aneurysms of the brain vessels. The Russian Ministry of Health guideline defines CoA as a congenital narrowing of the upper descending thoracic aorta bordering the insertion of the patent ductus arteriosus (PDA); it is caused by interposition of ductal tissue forming a concentric fold. The ESC considers CoA part of a generalised arteriopathy, and not only a narrowing of the aorta; it occurs as a discrete stenosis or as a long, hypoplastic aortic (arch) segment, and ectopic locations are rare. CoA accounts for 6–7% of congenital heart defects according to the Russian guideline and 6–8% according to MSD. A bicuspid aortic valve is present in up to 60% of patients with CoA according to the Russian guideline and in up to 85% according to the ESC. Other associated lesions include ventricular septal defect, subvalvular and supravalvular aortic stenosis, (supra)mitral valve stenosis, Shone complex and intracerebral aneurysms (in up to 10%). CoA occurs in 10–20% of patients with Turner syndrome; an association with Williams–Beuren syndrome has been described. Proximal to the coarctation there is pressure overload (left ventricular hypertrophy and hypertension in the upper part of the body, including the brain); distal to it there is hypoperfusion of the abdominal organs and lower extremities; collaterals develop via intercostal, internal mammary, scapular and other arteries. ## Symptoms What happens depends on how severe the narrowing is: severe coarctation shows in the first days of life, while mild coarctation may only be found in an adult who is being checked for high blood pressure. In a newborn with critical coarctation, blood flow to the lower half of the body depends on the open ductus arteriosus. When the duct closes, the baby passes less and less urine, the bowel works less well and shock may develop; this can happen within the first 7–10 days of life. The pulses in the legs are then weak or cannot be felt, and blood pressure in the legs is lower than in the arms or cannot be measured. In infants without the critical form, signs of heart failure come to the fore: shortness of breath, a fast heartbeat, sweating, tiring quickly when crying and feeding, and poor weight gain. Children aged 1 to 15 usually have no complaints, and the defect is found by chance, from a heart murmur and raised blood pressure. In older children and adults the main sign is high blood pressure in the arms. There may be headaches, ringing in the ears, nosebleeds, "floaters" or flashes in front of the eyes, cold feet and leg pain during exercise. A systolic blood pressure gradient of ≥ 20 mm Hg between upper and lower extremities, weak or absent pulses in the lower extremities, or radiofemoral pulse delay indicate significant CoA. 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 in the legs. In newborns with compensated duct-dependent flow, leg pulses and blood pressure may be comparable to those in the arms even with critical obstruction; an oxygen saturation difference of more than 3% between the right arm and the lower extremities should raise suspicion of CoA. A systolic murmur along the left sternal border, loudest in the interscapular area to the left of the spine, is typical; collaterals may cause continuous murmurs, and in a pinpoint CoA murmurs may be completely absent. Heart failure rarely develops after the neonatal period; according to the Russian guideline, only 5% of children who have survived infancy have signs of it. ## How it is diagnosed A simple check of blood pressure in the arms and legs, and comparing the pulses in the arms and legs, helps to suspect the defect. The diagnosis is confirmed by an ultrasound scan of the heart ([echocardiography](../../diagnostic/echocardiography/)) with Doppler. Teenagers and adults, and patients before surgery, have a CT or MRI scan of the aorta, which shows the whole aorta. Blood pressure monitoring over 24 hours helps to show how high the blood pressure is. Transthoracic echocardiography is recommended for children and adults with CoA, but direct imaging of the arch and proximal descending aorta is often limited, and in the presence of extensive collateral arteries Doppler gradients are not reliable and are often underestimated. Cardiac MRI and CT, including 3D reconstruction, are the preferred non-invasive techniques to evaluate the entire aorta in adolescents and adults; for surgical planning the Russian guideline prefers contrast-enhanced MRI. The chest X-ray shows a "3" sign in the upper left mediastinal shadow and rib notching from dilated intercostal collaterals, seldom seen before age 5; the ECG usually shows left ventricular hypertrophy but may be normal, and neonates and infants with severe CoA usually have right rather than left ventricular hypertrophy. Aortic catheterisation is performed in the setting of interventional treatment; it is not recommended for diagnosis in isolated CoA. ## How it is treated Coarctation is repaired by surgery or through the blood vessels with a catheter; the method depends on the anatomy of the aorta and on the approach preferred by the centre. Newborns with the critical form need urgent surgery. Until then the baby is given a medicine from the prostaglandin group into a vein, which keeps the ductus arteriosus open. In the first year of life the narrowed segment is usually removed and the ends of the aorta are sewn together. Older children and adults increasingly have a stent placed through a blood vessel. A narrowing that comes back after surgery is widened with a balloon or also treated with a stent. If blood pressure stays high, it is treated in the same way as [high blood pressure](../../disease/hypertension/) in general. Even after successful surgery, lifelong follow-up by a cardiologist is needed: at least twice in the first year, then at least once a year. The most common late complication is high blood pressure: by age 40 up to half of patients have it. The narrowing can come back (re-coarctation), so blood pressure in the arms and legs is compared regularly and the aorta is checked from time to time with MRI or CT. People with no remaining narrowing whose blood pressure is normal both at rest and during exercise can usually lead normally active lives without restriction. People with high blood pressure, remaining narrowing or other complications avoid heavy static (isometric) exercise, the more strictly the more serious these problems are. After successful treatment many women go through pregnancy without major problems, but with unrepaired coarctation, high blood pressure, remaining narrowing or an aortic aneurysm the risk of rupture of the aorta or of a brain aneurysm during pregnancy and delivery is higher. Urgent repair is recommended for critical (duct-dependent) CoA regardless of the gradient; until surgery a prostaglandin infusion maintains patency of the PDA. With stable haemodynamics and a gradient across the narrowing of more than 20 mm Hg, elective repair is recommended. Extended oblique end-to-end anastomosis has become the method of choice in the first year of life; adults with native CoA more often need grafts. According to MSD, surgical mortality is less than 5% for symptomatic infants and less than 1% for older children; according to the ESC, the surgical risk in simple CoA may currently be less than 1%, but it increases significantly beyond the age of 30–40 years. Transluminal balloon angioplasty is the method of choice for re-coarctation after open surgery; stenting is more effective than balloon angioplasty alone and has become the procedure of choice in older children and adults, and the ESC prefers covered stents. According to the ESC, balloon angioplasty in adults is only indicated for re-dilatation of previously stented aortas, whereas the Russian guideline names balloon angioplasty the method of choice for re-coarctation regardless of age. Follow-up is at least yearly; imaging of the aorta (preferably MRI) is commonly repeated every 3–5 years, and ambulatory blood pressure monitoring and echocardiography are done every year. A gradient of ≥ 20 mm Hg between upper and lower extremities indicates re-coarctation. Residual hypertension is investigated and treated according to the hypertension guidelines. ## When to call an ambulance A newborn with critical coarctation can become acutely ill as soon as the ductus arteriosus narrows or closes: shock develops, the kidneys stop working properly, the baby passes less and less urine, and the picture can mimic sepsis. Such a baby needs urgent surgery in a cardiac surgery centre. If a newborn suddenly becomes much more unwell or passes noticeably less urine, call your local emergency number (112 in the EU, 911 in the US and Canada, 999 in the UK). People with coarctation, especially if it is untreated, have a higher risk of bleeding in the brain from a ruptured aneurysm and of dissection or rupture of the aorta, including during pregnancy.