Patent ductus arteriosus vs Coarctation of the aorta
How to tell Patent ductus arteriosus and Coarctation of the aorta apart when a board question makes them look alike.
PDA is continuous machinery murmur; coarctation is upper-lower extremity pulse and pressure difference.
Side by side
Continuous machinery murmur below the left clavicle with bounding pulses from persistent aorta-to-pulmonary artery flow.
Aortic narrowing with upper-extremity hypertension, weak femoral pulses, leg symptoms, and rib notching in older patients.
Persistent ductus arteriosus creates postnatal left-to-right shunting from aorta to pulmonary artery.
Coarctation obstructs flow through the aorta and creates pressure gradients and collateral circulation.
Prematurity, continuous murmur, widened pulse pressure, and bounding pulses point PDA.
Arm-leg BP difference, delayed femoral pulses, and rib notching point coarctation.
The trap
Both can present asymptomatic in childhood and both are linked to chromosomal syndromes (PDA with congenital rubella and prematurity; coarctation with Turner syndrome and bicuspid aortic valve). The discriminator is pulse and BP: PDA gives a continuous machinery murmur at the left infraclavicular area with a widened pulse pressure and bounding peripheral pulses; coarctation gives upper-extremity hypertension with delayed and weakened femoral pulses (radio-femoral delay), plus rib notching from intercostal collaterals on adult chest X-ray. Differential cyanosis (pink upper body, cyanotic lower body) appears in either lesion when right-to-left shunting develops.
Watch it explained
The repair move
For ductus/aorta questions, compare pulse pressure pattern before naming the lesion.
Try a free question
CoreA premature infant has a continuous machinery-like murmur below the left clavicle with bounding pulses and widened pulse pressure. Which congenital lesion is most likely?
Show answer and explanation
Answer: A. Patent ductus arteriosus. PDA classically causes a continuous machinery murmur from persistent aorta-to-pulmonary artery flow.
Why the other choices are tempting
- B. Coarctation causes upper-extremity hypertension and diminished lower-extremity pulses.
- C. ASD causes fixed split S2.
- D. TOF causes cyanosis from RV outflow obstruction plus VSD/overriding aorta/RVH.
- E. VSD causes harsh holosystolic murmur at the lower left sternal border.
Flashcards
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What is the fastest separator for Patent ductus arteriosus vs Coarctation of the aorta?
PDA is continuous machinery murmur; coarctation is upper-lower extremity pulse and pressure difference.
What clue should make you choose Patent ductus arteriosus?
Continuous machinery murmur below the left clavicle with bounding pulses from persistent aorta-to-pulmonary artery flow.
Quick answers
What is the fastest way to tell Patent ductus arteriosus from Coarctation of the aorta?
PDA is continuous machinery murmur; coarctation is upper-lower extremity pulse and pressure difference.
What is the key clue for Patent ductus arteriosus?
Continuous machinery murmur below the left clavicle with bounding pulses from persistent aorta-to-pulmonary artery flow.
What is the key clue for Coarctation of the aorta?
Aortic narrowing with upper-extremity hypertension, weak femoral pulses, leg symptoms, and rib notching in older patients.
What is the common trap with Patent ductus arteriosus vs Coarctation of the aorta?
Both can present asymptomatic in childhood and both are linked to chromosomal syndromes (PDA with congenital rubella and prematurity; coarctation with Turner syndrome and bicuspid aortic valve). The discriminator is pulse and BP: PDA gives a continuous machinery murmur at the left infraclavicular area with a widened pulse pressure and bounding peripheral pulses; coarctation gives upper-extremity hypertension with delayed and weakened femoral pulses (radio-femoral delay), plus rib notching from intercostal collaterals on adult chest X-ray. Differential cyanosis (pink upper body, cyanotic lower body) appears in either lesion when right-to-left shunting develops.