Practice Easily Missed?

Coarctation of the aorta in the newborn

BMJ 2011; 343 doi: https://doi.org/10.1136/bmj.d6838 (Published 16 November 2011) Cite this as: BMJ 2011;343:d6838
  1. Mallika Punukollu, general practitioner1,
  2. Anthony Harnden, university lecturer in general practice2,
  3. Robert Tulloh, consultant, reader in paediatric cardiology3
  1. 1Kershaw Unit, Gartnavel Royal Hospital, Glasgow G12 0XH, UK
  2. 2Department of Primary Health Care, University of Oxford, Oxford OX3 7LF, UK
  3. 3Bristol Congenital Heart Centre, University Hospitals Bristol NHS Foundation Trust, Bristol BS2 8BJ, UK
  1. Correspondence to: M Punukollu mpunukollu{at}gmail.com
  • Accepted 7 September 2011

Key points

  • Suspected congenital heart disease in the newborn is a medical emergency

  • Coarctation of the aorta is the most commonly missed congenital heart disease

  • Remain alert for the possibility of coarctation of the aorta, especially in an infant presenting with poor feeding, failure to thrive, or signs of heart failure

  • Specific physical findings include a systolic murmur, weak or absent femoral pulses, and upper body hypertension

  • However, a normal result on examination of a newborn does not rule out congenital heart disease

  • Detection and treatment of coarctation of the aorta reduces morbidity and mortality from heart failure and improves long term outcome

Case scenario

A 14 day old infant presented with poor feeding, sleepiness, and loss of weight. He was born at term with normal vaginal delivery and was discharged within 24 hours after a newborn check was normal. Examination showed mild tachycardia, tachypnoea, weak femoral pulses, and a soft systolic murmur at the left sternal edge. The lungs were clear and the liver was enlarged by 3 cm. He was immediately referred to a specialist paediatric cardiology centre, where, after further investigation, a diagnosis of coarctation of the aorta was confirmed, prostaglandin was started, and the patient had successful surgical correction.

What is coarctation of the aorta?

Congenital heart disease is the commonest group of congenital diseases. It affects 19 in 1000 live births worldwide1 and accounts for 9% of infant deaths in the United Kingdom.2 Coarctation of the aorta is a discrete narrowing of the proximal descending aorta and accounts for 7% of congenital heart defects (figs 1 to 3 ).1 3

Figure1

Top: Normal heart. Bottom: Heart with coarctation of the aorta (arrows indicate direction of all blood flow)

Figure2

Coarctation of the aorta is a narrowing of the aorta, the major artery leading from the heart to the body. Blood pressure above the constriction is high, leading to upper limb hypertension. Below the constriction the blood pressure is low, causing poor perfusion and symptoms such as leg fatigue, cold feet, and weak femoral pulses

Figure3

Heart with coarctation of the aorta and patent ductus arteriosus. Blood flow is restricted through the coarctation but can flow through the open connection between the aorta and the pulmonary artery, the ductus arteriosus. Symptoms usually do not occur until the ductus closes, usually when the newborn is a few days to about 2 weeks old. After the closure, the blood supplied through the ductus stops causing an increase in afterload on the heart leading to heart failure, and low blood pressure can result

How common is coarctation of the aorta?

  • Coarctation of the aorta occurs in 1 per 2000-2500 live births worldwide1

  • It is the sixth most common form of congenital heart disease1

Why is coarctation of the aorta missed?

Coarctation of the aorta is the most commonly missed congenital heart disease,3 4 and many cases not diagnosed until adulthood or death are incorrectly attributed to sepsis.1

Coarctation of the aorta may be missed in newborns because of the low sensitivity (32%) of the neonatal screening examination.5 Moreover, cardiac symptoms may not develop before 48 hours of age and closure of the patent ductus arteriosus (fig 3).3 6

Other factors contributing to a delay in diagnosis include a lack of familiarity by clinicians with the clinical manifestations of coarctation of the aorta; 20% of babies with coarctation in the UK are undiagnosed at the 6-8 week examination.7 One study found that only 56% of eligible babies had a routine examination for signs of heart disease between 6 and 8 weeks of age, and even if an abnormality was suspected there were delays in referral. In another study about a quarter of babies with murmurs had structural heart disease but only about half were referred.8 In babies with coarctation of the aorta, 25-85% are estimated to have a bicuspid aortic valve.9 10 11 In addition, they may have other associated cardiovascular abnormalities, such as ventricular septal defect (in 15% of cases) and persistent ductus arteriosus (13%).11

Why does this matter?

Suspected congenital heart disease is a medical emergency. Thirty infants a year in California, USA, die of a missed or late diagnosis of critical congenital heart disease.3 A retrospective cohort study of 898 infants who died with congenital heart disease found that more than half of them died at home or in the emergency department and that coarctation of the aorta and hypoplastic left heart syndrome were the most commonly missed diagnoses and were associated with the highest mortality.3 Coarctation of the aorta was missed in 27% of missed cases of congenital heart diseases (n=152) with mean age at death 17 days.3 Studies have found that many of the complications (such as hypertension, coronary artery disease, congestive heart failure, recoarctation, aortic aneurysm, aortic rupture, and cerebrovascular accidents9 10 11) caused by delayed referral of children with coarctation of the aorta could have been prevented if the clinician had checked for the presence of femoral pulses,4 which is recommended by guidelines from England’s National Institute for Health and Clinical Excellence as part of the routine neonatal examination.12

Early diagnosis of coarctation of the aorta reduces morbidity and mortality from heart failure13 and is critical for the proper timing of therapeutic interventions. The repair of coarctation of the aorta during early childhood is associated with less systemic hypertension and improved long term outcome.9 10 11

How is coarctation of the aorta diagnosed?

Clinical features

Infants may be asymptomatic until closure of the ductus arteriosus. After closure detectable physical signs (hypertension and/or abnormal femoral pulse) develop by 5 days of age, and almost half of the children affected will develop severe symptoms before 14 days of age (that is, before the first vaccination visit).6 Infants may develop poor feeding, tachypnoea, cool legs and feet, and pale or possibly grey skin discoloration. These signs may reflect heart failure and cardiogenic shock.14 A retrospective study of 165 infants with congenital heart disease found that the commonest symptoms were breathlessness (75%), lower respiratory tract infections (45%), and failure to thrive (39%).15 Coarctation of the aorta may cause faltering growth because of breathlessness (causing poor feeding and low energy intake) and in some cases high energy requirements (causing insufficient energy for normal growth).16

Older children and adults may have exercise intolerance; symptoms of poor perfusion such as leg fatigue, cold feet, and claudication; headache (resulting from hypertension); and symptoms of heart failure.14

A harsh systolic murmur (often absent in newborns) over the left sternal border indicates a 54% chance of an underlying cardiac malformation.17 Weak or absent femoral pulses are found in 92% of infants with coarctation of the aorta,18 and in these cases referral should be made to a paediatrician for blood pressure measurements. Upper limb hypertension has been found in 97% of infants with coarctation of the aorta18 and a systolic blood pressure that is ≥20 mm Hg higher in the arms than in the legs is evidence of coarctation of the aorta (specificity 92%).19 However, a negative finding on the four limb blood pressure measurement does not exclude the condition.19

Investigations

Pulse oximetry in the feet can detect 92% of duct dependent congenital heart disease (coarctation of the aorta, transposition of the great arteries, and hypoplastic left heart syndrome) and has a very low false positive rate (0.17%).20 In addition, it is easy to use, reliable, and cost effective.20

Imaging and haemodynamic evaluation by transthoracic echocardiography is the recommended investigation to confirm the type of congenital heart disease.21 Transthoracic echocardiography has a sensitivity of 91% in detecting coarctation of the aorta and 100% for all cardiac defects.22

How is coarctation of the aorta managed?

The initial treatment, after resuscitation of the neonate, would involve the use of prostaglandin to reopen the arterial duct.23 This usually leads to stabilisation, often in conjunction with intensive care support. Surgical repair usually takes place within a few days of presentation (fig 4).

Figure4

Surgical management of coarctation of the aorta: resection with end to end anastomosis

In older children, control hypertension after surgery with β blockers, angiotensin converting enzyme inhibitors, or angiotensin receptor blockers as first line medications. In coarctation of the aorta, stent insertion at cardiac catheterisation has become the treatment of first choice in older children and in adults. This is most appropriate when there is a localised narrowing at the site of the coarctation, rather than a hypoplastic arch, which might require surgery.24

Long term follow-up postoperatively is mandatory because of the risk of systemic hypertension, aneurysm formation, or emergence of symptoms associated with congenital heart disease.

Notes

Cite this as: BMJ 2011;343:d6838

Footnotes

  • This is one of a series of occasional articles highlighting conditions that may be more common than many doctors realise or may be missed at first presentation. The series advisers are Anthony Harnden, university lecturer in general practice, Department of Primary Health Care, University of Oxford, and Richard Lehman, general practitioner, Banbury. To suggest a topic for this series, please email us at easilymissed{at}bmj.com.

  • Contributors: MP wrote the first draft of the article, which was modified by AH and RT. All authors agreed the final draft.

  • Funding: None.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • Patient consent not required (patient anonymised, dead, or hypothetical).

References

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