What are the possible cardiovascular complications of Down syndrome?

Updated: Apr 30, 2018
  • Author: Gratias Tom Mundakel, MBBS, DCH; Chief Editor: Maria Descartes, MD  more...
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Cardiovascular complications are important in Down syndrome. [22, 58] Children who seem asymptomatic at birth and do not have a murmur may have a significant cardiac defect. Children who have left-to-right shunts, such as atrioventricular septal defects, may develop signs of heart failure at age 1-2 months, manifested by tachypnea, poor feeding, and failure to thrive. If increased pulmonary vascular resistance is noted, the left-to-right shunt may be minimized, thus preventing early heart failure. However, if left undetected, this condition may lead to persistent pulmonary hypertension with irreversible pulmonary vascular changes.

Generally, surgery to correct the heart defect is delayed until the infant is larger and is strong enough to tolerate the operation, which is usually performed at age 6-9 months. Most children do very well and thrive after the procedure.

In patients with an atrioventricular septal defect (AVSD), symptoms usually occur in infancy as a result of systemic-to-pulmonary shunting, high pulmonary blood flow, and an increased risk of pulmonary arterial hypertension. Increased pulmonary resistance may lead to a reversal of the systemic-to-pulmonary shunt accompanied by cyanosis (ie, Eisenmenger syndrome). To reduce the risk of this complication, children with a large AVSD without pulmonary obstruction should have their defect repaired before the age of 4 months. [2]

Patients with Down syndrome are considered to be at higher risk for pulmonary arterial hypertension than patients without Down syndrome. This is because of the diminished number of alveoli, the thinner media of pulmonary arterioles, and the impaired endothelial function in these patients.

Early corrective cardiac surgery is warranted to prevent irreversible pulmonary vascular lung damage. Moreover, new medical treatment strategies (eg, prostacyclin, endothelin receptor antagonist and phosphodiesterase-5-inhibitor) have been demonstrated to substantially improve clinical status and life expectancy of patients with pulmonary arterial hypertension.

Coronary artery disease–related mortality is surprisingly low. Pathologic studies have revealed decreased levels of atherosclerosis in Down syndrome. Individuals with Down syndrome also have a decreased risk of hypertension.

Acquired heart valve disease is common in Down syndrome and includes mitral valve prolapse and aortic regurgitation. [31]

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