Cardiology Internal Medicine

Coarctation of the Aorta (CoA)

Coarctation of the Aorta

Introduction – Coarctation of the Aorta

Coarctation or narrowing of the aorta (coarctatio aortae) is a common cardiovascular abnormality. About 5% of all adults with congenital heart defects have coarctation. Aortic coarctation can occur as part of other complex cardiovascular malformations, but is usually isolated. This overview summarizes the characteristics of the isolated form of coarctation of the aorta.

Coarctation is much more common in men than in women. Adult patients with surgically corrected coarctation can usually be recognized by a left lateral thoracotomy scar.

Pathophysiology

Non-corrected coarctation exposes the left ventricle to a pressure load similar to that in aortic stenosis, although the stenosis in coarctation only affects the lower body half. The reduction of perfusion pressure in the lower body half allows the blood pressure in the upper body half of a patient with coarctation to become very high. After surgical or catheter-based correction, normal circulation properties are restored.

Associated malformations

  • A Bicuspid aortic valve is present in the majority of patients with coarctation. Thus, for patients with known coarctation, the aortic valve should be evaluated to ascertain whether it is bi- or tricuspid. Conversely, a patient with a bicuspid aortic valve should be evaluated for coarctation.
     
  • There is an overrepresentation of cerebral arterial aneurysm in patients with coarctation.
     
  • Individuals with Turner syndrome have a strong overrepresentation of coarctation.

Clinical Findings and Treatment


In CoA patients that have undergone surgical correction, the anatomy of the aortic arch and descending aorta is usually normal or almost normal. Older adults who have been treated for coarctation have often been operated with subclavian flap technology, ie use of the subclavian artery as an endogenous graft. The surgical result is often very good. However, the patient sometimes has problems with blood supply to the left arm, usually asymptomatic. There is often a reduced pulse in the left radial artery and the patient has lower or difficult to measure blood pressure in the left arm.

Today, surgery with reconstruction of the aortic arch (removal of the coarctation) is more common, but insertion of Gore-Tex grafts or other foreign materials are other possible options.


Complications – Coarctation of the Aorta

Mild to moderate coarctation belongs to the heart defects that are sometimes first detected in adulthood. Newly discovered hypertension in younger patients should therefore always raise suspicion of undiagnosed coarctation, primarily through blood pressure measurement of arm-legs and by checking pulses in the groin. Blood pressure is usually equal in both arms but substantially lower in the legs of a patient with significant, untreated coarctation.

Patients with corrected coarctation are at increased risk of developing hypertension. The Swedish quality register SWEDCON states that at the age of 36, 52% of patients with coarctation have developed hypertension. Development of hypertension should lead to reassessment of the possibility of potential re-coarctation, but otherwise, the treatment is the same as in the case of hypertension in other patients. The diagnostic procedures that may be relevant include MRI/CT but often, catheterization is needed and is handled via or in collaboration with a regional GUCH unit.

Complications related to aortic surgery occur often in the form of aneurysm formation and residual/re-coarctations. Aneurysm formation is rare but may cause symptoms of aortic dissection/aneurysm, including hemoptysis.

There is support in the literature that patients with coarctation are at increased risk of developing coronary heart disease, but recent large-scale registry studies have not been able to substantiate this claim.


Follow-up – Coarctation of the Aorta

Patients with coarctation should be followed by physicians who are experienced in the treatment of GUCH (Grown-up congenital heart disease) in collaboration with the regional GUCH unit. Morphological imaging of the thoracic aorta should be done in adulthood and repeated at varying intervals depending on appearance.

In case of corrected coarctation with good results and a thoracic aorta without significant deviations, morphological checks can be done at sparse intervals, 5-10 years, primarily by MRI. Clinical checks including arm and leg blood pressure monitoring, ECG (left ventricular hypertrophy?) should be done every two years according to the guidelines of the European Cardiovascular Association.

Screening for cerebral aneurysm is not indicated, but clinical vigilance should be present in sudden, severe headache.

Abnormal remnants or coarctation can be clinically relatively easily ruled out by pulse palpation and blood pressure measurement in the arm and leg. Elevated blood pressure in the arm compared to the leg, especially if the pressure gradient is more than 20 mmHg, should raise suspicion of residual coarctation. In these patients, blood pressure should be measured in the right arm.

Endocarditis prophylaxis is considered not to be recommended according to newer guidelines.

Sports and physical activities at the recreational level can usually be undertaken without restrictions in a patient with a well-corrected and followed-up coarctation. For elite-level sports events, there are usually no restrictions, but activities with a very high static load should prompt closer discussion with sports-interested GUCH physicians.

Pregnancy can be carried out with minimal risk in the majority of women who have had their coarctation corrected and adequately monitored and where residual coarctation and/or aneurysm is not present. Worth noting is that women with Turner syndrome have a significantly increased risk of coarctation and an undiagnosed, dense coarctation exposes the pregnant mother as well as the fetus to potentially very large risks.

Note: 

  • Young patients with newly discovered hypertension – may be undiagnosed coarctation.
     
  • In the absence of peripheral artery disease, the blood pressure in the legs is higher than in the arms. A lower leg blood pressure, especially if the pressure drop is more than 20 mmHg, indicates the presence of significant coarctation.
     
  • In non-corrected coarctation, the pressure is equal in both arms, after surgical intervention the pulse is often missing in the left arm.
     
  • Coarctation is strongly linked to a higher risk of developing hypertension.

Further Reading