Patent Ductus Arteriosus

Question 1

What is a PDA

Answer 1

A PDA is connection between the descending aorta (just distal to left subclavian A) and proximal pulmonary artery. In the foetal circulation it serves to aid in the shunting of blood away from the lungs in utero.

Question 2

What does the ductus arteriosus become in adults

Answer 2

ligmentum arteriosus

Question 3

What prevents normal PDA closure

Answer 3

Prostaglandins

Question 4

What medications would you given to close a PDA

Answer 4

Indomethacin
Ibuprofen

Question 5

In what scenarios would it be beneficial to keep a PDA patent

Answer 5

Cyanotic heart disease such as ToF/ Transposition of great vessels

Question 6

What are the complications of a PDA

Answer 6

Increased blood flow in pulmonary truck leads to pulmonary HTN. Increased venous return to left atrium can lead to volume overload to LA and LV.

complications include
- RVF
- LVF
- Eisenmengers

Question 7

How may PDAs present

Answer 7

Asymptomatic
IE
Heart failure
Eisenmenger’s

Question 8

Clinical signs of PDA (non auscultation)

Answer 8

Clubbing/ cyanosis (is Eisenmenger’s)
A waves (Pul HTN)
CV Waves (functional TR)
Parasternal heave
Loud P2
Thrill in infraclavicular area

Question 9

Auscultation of PDA

Answer 9

Uninterrupted murmur ‘machine like’
Loud P2
radiated to left scapula
Murmur will get quieter with Eisenmenger’s

Question 10

Mnemonic for clinical signs of PDA

Answer 10

MBCHB:
Machine like murmur
Bounding pulse
Collapsing pulse
Heave
BP (wide) wide pulse pressure

Question 11

Why may you get asymmetrical cyanosis/ clubbing if Eisenmenger’s occurs

Answer 11

Rt UL normal
Lt UL clubbed + cyanosed
both LL cyanosed and clubbed

depends on degree in which blood can enter the left subclavian artery on shunt reversal

Question 12

How is PDA graded on clinical features

Answer 12

Mild: continuous murmur
Moderate: Wide PP, collapsing pulse, volume overloaded LV, pulmonary HTN
Severe: Eisenmenger’s, cyanosis/ clubbing, absence of murmur

Question 13

Causes of PDA

Answer 13

Neonatal rubella
Birth at altitude
Transposition of great vessels
Prematurity
Congenital

Question 14

Investigations for PDA

Answer 14

ECG: ventricular hypertrophy (bilateral), P mitrale
CXR: Pulmonary plethora, visible ductus if calcified
TTE
may require cardiac catheterisation for pulmonary pressures

Question 15

Management of PDA

Answer 15

Small may not require closure

Medical - indomethacin
Surgical - Open closure, percutaneous closure

Follow up in adult congenital heart disease clinic

Question 16

Contraindication for closure of PDA

Answer 16

Eisenmenger’s
irreversible pulmonary HTN