Patent Foramen Ovale

Question 1

What is a patent foramen ovale?

Answer 1

• Remnant of normal foetal circulation - allows shunting between two atria
• Occurs in 25-30% of the population

Question 2

What normally happens to PFO after birth?

Answer 2

• Increase in pulmonary blood flow = increased pulmonary venous for to LA = increased LAP
• LAP > RAP, pressing valve of PFO against septum secundum effectively closing PFO
• Fuse over time

Question 3

Identifying PFO with echo?

Answer 3

• Can see flap separation from atrial septum - best seen with TOE
• Usually best seen in subcostal 4 chamber
• Agitated saline bubble study

Question 4

Agitated saline bubble study for PFO?

Answer 4

• If PFO clinically suspected, ASCi performed
• Bubbles crossing IAS into LA and LV when PFO present
• With Valsalva, transient increase in RAP may revel R-L shunt across PFO
• Aneurysmal IAS bows to the left with Valsalva (RAP > LAP)

Question 5

Surgical methods of ASD closure?

Answer 5

• Simple suture closure
• Patch closure

Question 6

Percutaneous methods of ASD closure?

Answer 6

• Amplatzer device (figure of 8 artifact)
• Helex septal occluder devices

Question 7

Role of echo post ASD/PFO closure?

Answer 7

1. Assessment of RV size and systolic function (to determine if right heart has returned to normal size or decreased in size)
2. Detection of any residual shunts (trace amount of intra-device flow may be seen and is normal)
3. Evaluation of position of closure device (if closed via this method)

Question 8

Potential ‘rare’ problems of percutaneous closure?

Answer 8

1. Device embolization
2. Partial dehiscence
3. Cardiac perforation
4. Device erosion
5. Thrombus formation

Question 9

When may device migration/embolisation occur?

Answer 9

• May occur with smaller devices and insufficient tissue rims
• Device may migrate/embolise into the LV

Question 10

When may device dehiscence occur?

Answer 10

If occluder device has separated from plane of IAS at anterosuperior margin of device

Question 11

When may device erosion/cardiac perforation occur?

Answer 11

• Occluder device protruding into pericardial space consistent with device erosion and cardiac perforation
• Erosion may occur when oversized device rubs against cardiac walls with each cardiac cycle