What is coarctation of the aorta? 

Coarctation of the aorta (CoA) is a congenital heart defect characterized by a significant narrowing of the aorta, the body’s main artery that carries oxygen-rich blood from the heart to the rest of the body. This narrowing usually occurs at the “isthmus,” the area just past the point where the arteries branch off to the head and arms. This structural “bottleneck” forces the left ventricle to pump at much higher pressures to push blood through the obstruction, leading to high blood pressure in the upper body and reduced blood flow to the lower body and abdominal organs. 

Coarctation accounts for approximately 5% to 8% of all congenital heart defects in the UK. Because the heart must work significantly harder to overcome the narrowing, the muscle of the left ventricle can become dangerously thickened (hypertrophy) over time. If left untreated, CoA can lead to premature heart failure, aortic rupture, or stroke. While often diagnosed in newborns, “silent” cases may go unnoticed until adulthood, when they are frequently discovered during investigations for unexplained high blood pressure. 

What We will cover in this Article 

• Anatomy of the aortic narrowing and its hemodynamic impact. 

• Recognising symptoms in neonates vs. adults. 

• Clinical differentiation: Duct-dependent vs. isolated coarctation. 

• The link between CoA and Turner Syndrome. 

• Modern treatment options: Surgery vs. Balloon Angioplasty and Stenting. 

• 2025 clinical data on long-term blood pressure outcomes. 

The Anatomy of Aortic Narrowing 

In a healthy heart, the aorta is a wide, arching vessel that allows blood to flow freely to the entire body. In coarctation, a portion of this vessel is pinched or constricted. This typically occurs near the ductus arteriosus, a fetal blood vessel that closes shortly after birth. When the ductus closes, the surrounding aortic tissue can sometimes tighten, creating the coarctation. 

The result is a pressure gradient: 

• Pre-stenotic (Before the narrowing): High blood pressure in the heart, head, and arms. 

• Post-stenotic (After the narrowing): Low blood pressure and weaker pulses in the legs and lower abdomen. 

This pressure imbalance is the hallmark of the condition and is the primary reason why clinicians check for “radio-femoral delay” a delay in the pulse felt at the groin compared to the wrist. 

Clinical Presentation: Neonates vs. Adults 

The timing of symptoms depends on the severity of the narrowing. In cases of “critical” coarctation, a newborn may appear healthy for the first few days while the ductus arteriosus is still open. Once it closes, blood flow to the lower body is severely restricted, leading to rapid clinical collapse. 

The following table summarizes the different clinical presentations seen across age groups: 

Feature	Neonatal Presentation	Adult Presentation
Primary Symptom	Pale skin, irritability, heavy breathing	Frequent headaches, leg cramps during exercise
Blood Pressure	Significant upper/lower body difference	Persistent hypertension (high BP)
Pulses	Weak or absent femoral (groin) pulses	Strong pulses in arms, weak in legs
Heart Sounds	Harsh systolic murmur	Continuous murmur over the back
Complications	Shock, organ failure, acidosis	Early-onset coronary disease, brain aneurysm

Causes and Associated Conditions 

While the exact cause is often unknown, research suggests that coarctation occurs during the first eight weeks of pregnancy. It is frequently associated with other cardiac and genetic conditions. For instance, up to 50% of people with coarctation also have a “bicuspid aortic valve,” where the valve has only two flaps instead of three. 

• Turner Syndrome: Approximately 10% to 15% of girls with Turner Syndrome are born with coarctation of the aorta. 

• Genetic Triggers: Deletions on specific chromosomes can affect the development of the aortic arch. 

• Maternal Factors: 2025 clinical data suggests that maternal metabolic health and environmental exposures in the first trimester play a role in aortic arch formation. 

Treatment: Surgery and Stenting 

The goal of treatment is to remove the narrowing and restore normal blood flow. The choice of procedure depends on the patient’s age and the length of the narrowed segment. 

1. Surgical Repair: Most common in infants. The surgeon removes the narrowed part and sews the two healthy ends back together (end-to-end anastomosis). 

2. Balloon Angioplasty: A catheter with a balloon is used to stretch the narrowing. This is often used for “re-coarctation” if the narrowing returns after surgery. 

3. Stenting: A metal mesh tube (stent) is placed inside the aorta to keep it open. This is now the preferred treatment for older children and adults. 

To Summarise 

Coarctation of the aorta is a structural narrowing that creates a dangerous pressure imbalance between the upper and lower body. While it can cause life-threatening shock in newborns, it can also remain a “hidden” cause of high blood pressure in adults. Modern treatments like surgical resection and stenting are highly effective, but 2025 clinical data emphasizes that repair is not a “cure.” Patients must remain under the care of a cardiologist for life to manage potential high blood pressure and ensure the aorta remains open and healthy. 

If your baby appears very pale, has cold legs, or is struggling to breathe, call 999 immediately. 

If you or your child experience sudden, severe chest pain or a thunderclap headache, call 999 immediately. 

Authority Snapshot (E-E-A-T Block) 

This article was reviewed by Dr. Stefan Petrov, a UK-trained physician (MBBS) with postgraduate certifications in ACLS and BLS. Dr. Petrov has extensive clinical experience in general medicine and emergency care, having worked in hospital wards and intensive care units where the management of acute hypertension and neonatal cardiac emergencies is a priority. His expertise ensures this information on coarctation of the aorta is accurate, safe, and aligned with current NHS and British Congenital Cardiac Association (BCCA) standards.