Patent Ductus Arteriosus, Emergency Medicine

Basics

Description

Patent vessel in the fetal heart connects the pulmonary trunk to the descending aorta.
Shortly after birth, changes normally provoke contraction, closure, and fibrosis:
- Sudden increase in the partial pressure of oxygen
- Changes in the synthesis and metabolism of vasoactive eicosanoids
In the preterm infant, persistent patency of the ductus may be a normal life-saving response.
The patent ductus usually has a normal structural anatomy.
Patency results from hypoxia and immaturity.
In the full-term newborn, patency of the ductus is a congenital malformation.
Deficiency of both the mucoid endothelial layer and the muscular media of the ductus
As pulmonary vascular resistance falls, aortic blood is shunted into the pulmonary artery.
Extent of the shunt reflects the size of the ductus and the ratio of the pulmonary to systemic vascular resistances.
Up to 70% of the left ventricular output may be shunted through the ductus to the pulmonary circulation.
Risk factors:
- Premature birth
- Coexisting cardiac anomalies
- Conditions resulting in hypoxia
- High altitude
- Maternal rubella infection
- Female-to-male ratio, 3:1

Etiology

Prematurity
Congenital anomaly
Hypoxia
Prostaglandins

Diagnosis

Signs and Symptoms

History

Isolated patent ductus arteriosus (PDA), an unanticipated event
PDA, as part of a larger congenital cardiac anomaly, may be diagnosed by US during pregnancy.

Physical Exam

Asymptomatic when the PDA is small, but otherwise may present with a range of findings.
Congestive heart failure (CHF), often in 1st day of life
Wide pulse pressure
Prominent apical impulse
Thrill
Systolic and continuous murmur.
Sounds like a humming top or rolling thunder
Begins soon after onset of the 1st sound, reaches maximal intensity at the end of systole, and wanes in late diastole
Localized to the 2nd left intercostal space or radiates down the left sternal border toward the apex or to the left clavicle
Recurrent pulmonary infections
Retardation of physical growth

Essential Workup

Establish the diagnosis with imaging studies.
Rule out complications such as heart failure and endocarditis.

Diagnosis Tests & Interpretation

Lab
Unhelpful in making the diagnosis
Imaging

CXR:
- Usually normal in infants
- In children and adults:
  - Increased intrapulmonary markings
  - Calcifications
  - Left ventricle and left atrial enlargement
  - Dilated ascending aorta
  - Dilated pulmonary arteries
EKG:
- Abnormal if the ductus is large:
  - Left ventricular hypertrophy
  - Right ventricular hypertrophy is a sign of greater severity.
Echocardiography:
- Normal if the ductus is small
- Left atrial enlargement
- Size of the ductus can be determined by scanning from the suprasternal notch.
- Doppler studies will determine aortic to pulmonary artery flow during diastole.
Cardiac catheterization:
- Normal or increased right-sided pressure
- Oxygenated blood in the pulmonary artery confirms left-to-right shunting.
- Injection of contrast into the ascending aorta shows opacification of the pulmonary arteries.

Differential Diagnosis

Venous hum:
- Common insignificant bruit
- Heard in the neck or anterior portion of the chest
- Soft humming sound in systole and diastole
- Decreased by light compression of the jugular venous system
Total anomalous pulmonary venous connection to the innominate vein:
- Continuous murmur like venous hum
Aorticopulmonary septal defect:
- Murmur is often only systolic.
- Heard at the right sternal border
Ruptured sinus of Valsalva
Coronary arteriovenous fistulas
Anomalous origin of left coronary artery from the pulmonary artery
Absence or atresia of pulmonary valve
Aortic insufficiency with ventricular septal defect
Peripheral pulmonary stenosis
Truncus arteriosus

Treatment

Supplemental oxygen if CHF

Pre-Hospital

Monitoring and oxygen

Initial Stabilization/Therapy

Small, asymptomatic shunts may not need closure.
Pulmonary support
Supplemental oxygen

Ed Treatment/Procedures

Sodium and fluid restriction
Correction of anemia to hematocrit >45%
Antibiotic prophylaxis for endocarditis
Preterm infants:
- Usually closes spontaneously
- Varies with the magnitude of shunting and severity of respiratory distress syndrome
- Pharmacologic inhibition of prostaglandin synthesis with indomethacin during the 1st 2 " 7 days of life
Full-term infants and children:
- Surgical closure is required, even in asymptomatic patients, as spontaneous closure is rare.
- Ligation and division
- Transfemoral catheter technique to occlude PDA with foam plastic plug or double umbrella

Medication

Indomethacin: 0.2 " 0.25 mg/kg per dose; repeat q12 " 24h for 3 doses

Follow-Up

Disposition

Admission Criteria

Heart failure
Endocarditis
Pulmonary hypertension

Discharge Criteria

Asymptomatic
Prophylactic antibiotics
Close follow-up with plans for early surgical closure

Issues for Referral
A pediatric cardiologist/neonatologist should be involved in all patients who have any evidence of heart failure, particularly if pharmacologic management is being considered.

Pearls and Pitfalls

CHF may cause decrease in glomerular filtration rate and urinary output.
Indomethacin may cause GI bleeding.

Additional Reading

Dorfman AT, Marino BS, Wernovsky G, et al. Critical heart disease in the neonate: Presentation and outcome at a tertiary care center. Pediatr Crit Care Med. 2008;9:193 " 202.
Laughon M, Bose C, Benitz, WE. Patent ductus arteriosus management: What are the next steps. J Pediatr. 2010;157(3):355 " 357.
Moore P, Brook MM. Patent ductus arteriosus and aortopulmonary window. In: Allen HD, Driscoll DJ, Shaddy RE, et al., eds. Moss and Adams ' Heart Disease in Infants, Children, and Adolescents: Including the Fetus and Young Adult. 8th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013:722 " 745.
Nemerofsky SL, Parravicini E, Bateman D, et al. The ductus arteriosus rarely requires treatment in infants >1000 grams. Am J Perinatol 2008;25:661 " 666.
Webb GD, Smallhorn JF, Therrien, J, et al. Chapter 65: Congenital heart disease. In: Bonow RO, Mann DL, Zipes DP, et al., eds. Braunwalds Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, PA: Elsevier Saunders; 2012:1411 " 1468.

Codes

ICD9

747.0 Patent ductus arteriosus

ICD10

Q25.0 Patent ductus arteriosus

SNOMED

83330001 Patent ductus arteriosus (disorder)
125964004 Patent ductus arteriosus with right-to-left shunt (disorder)
125963005 Patent ductus arteriosus with left-to-right shunt
253686000 Patent ductus arteriosus - persisting type (disorder)

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