Coarctation of the Aorta: A Not-So-Common Condition

Coarctation of the aorta (CoA) is a heart condition present from birth. It’s diagnosed when the aorta, the largest artery in the body, becomes narrow, making it harder for blood to flow through. If you’ve ever had your garden hose kink up while watering your rose bushes, you already understand the concept. 

The severity of CoA depends on the degree of narrowing. Some people have only slightly narrowed aortas, which allows for mostly normal blood flow; others have dramatic narrowings, requiring the heart to work much harder and quickly leading to heart failure. Whether mild or major, CoA requires medical intervention.

CoA can occur in isolation, but it’s much more commonly found alongside additional heart defects. Among its most frequent partners is a bicuspid aortic valve, which is an aortic valve with two leaflets rather than the normal three. CoA may also occur in conjunction with holes in the heart (septal defects) as well as more complicated heart conditions.

How Common is Coarctation of the Aorta?

CoA is fairly rare in the general population, with an incidence of roughly 1 in 2500 live births. For comparison, a ventricular septal defect (VSD), which is a tiny hole between the right and left ventricles and the most common congenital heart defect, occurs in roughly 1 in 250 live births. 

Certain populations are at increased risk of heart conditions, including CoA. Girls born with Turner’s Syndrome, a female-specific genetic condition caused by an incomplete or missing X chromosome, are especially susceptible to aortic issues, with roughly 5-10% diagnosed with coarctation.   

Outside of genetic syndromes, CoA is roughly twice as common in boys and nearly three times more common in twins. 

What Causes Coarctation of the Aorta?

Most cases of CoA have no obvious cause; the majority of patients have no underlying condition and no family history. Genetic influences may play a role (even in the absence of a genetic syndrome); however, a pathogenic CoA gene has yet to be discovered. CoA is not caused by something mothers do (or do not) during their pregnancies; it’s not influenced by diet, exercise, or injury when babies are in utero. But while the exact cause is elusive, its development is better understood. 

Before birth, babies develop a temporary blood vessel called the ductus arteriosus. Because babies in the womb receive oxygen from the placenta rather than the lungs, this vessel allows blood to skip the lungs and flow directly to other parts of the body. Once babies are born, the ductus arteriosus, no longer needed, closes. In CoA, this closure comes with complications, with some of the ductal tissue extending into the aorta. When the vessel contracts as part of its intended closure, it closes part of the aorta as well, leaving a narrow section and causing coarctation. 

CoA may also be the result of an underdeveloped aorta, one that fails to reach normal diameter. 

Coarctation of Aorta Symptoms

The symptoms of CoA range widely. Babies who are born with severe narrowing may rapidly develop heart failure, with signs that include weak pulses, rapid breathing, constant crying, turning blue, and poor feeding within days or weeks of birth. Those born with mild forms might not be diagnosed until they’re well into childhood. 

Although it’s rare, some patients aren’t diagnosed until adulthood; in these instances, high blood pressure (especially when it’s higher in the arms than the legs) is usually the first sign. Other signs include headaches, nosebleeds, cold feet and hands (due to reduced blood flow), leg pain, reduced exercise tolerance, and shortness of breath. Some people with CoA have heart murmurs, but not everyone. 

Diagnosing CoA before birth, via a prenatal ultrasound, is very challenging because the narrowing doesn’t develop until after the baby is born. Even so, there are visible signs that a baby may be especially likely to develop CoA, including a smaller-than-normal left ventricle, a smaller-than-normal ascending aorta or aortic arch, and a thinner-than-expected aortic isthmus (a short, naturally narrow area of the aorta particularly prone to coarctation). Seeing these signs on prenatal scans doesn’t diagnose CoA, but it puts doctors (and parents!) on high alert. 

How is Coarctation of the Aorta Treated?

CoA is treated through surgical or catheter-based interventions, although newborns may be given prostaglandins to keep the ductus aterisos open as a temporary solution. Surgery is the gold-standard treatment; it typically involves removing the narrowed segment and reconnecting the healthy aorta ends or enlarging the narrowed aorta with a synthetic or biological patch. Surgery is done through the left side of the chest, resulting in a scar on the left side and back rather than down the front (like most heart operations). 

Minimally invasive catheter-based procedures (balloon angioplasty) are commonly used as well, especially in older children, adolescents, and adults. During balloon angioplasty, a catheter with a small balloon is inserted into the aorta via (most often) the femoral artery. It’s then inflated, widening the aorta. A stent may be placed to reduce the chance of re-narrowing.

The Outlook

Once upon a time, CoA was a devastating diagnosis with few options and even fewer happy endings, but modern surgical techniques, innovative science, and cardiac advancements have made it possible for patients to live long lives.

In fact, those with CoA enjoy normal life expectancies, as long as they’re monitored for late complications. Like many heart conditions, CoA is never considered cured, not even after surgery. Those affected are at a significantly increased risk of high blood pressure, recurrent narrowing, and aneurysms (at the site of repair, elsewhere in the aorta, and in the brain), and women may require a high-risk medical team during pregnancy. Those with CoA should receive lifelong care from a cardiologist who specializes in congenital heart disease.

When issues are addressed promptly through monitoring and vigilance, patients with CoA aren’t just given the gift of life; they’re empowered to enjoy the ride.