Exam Cram

• Patent Foramen Ovale (PFO) is a common type of atrial septal defect present in 25% of the UK population

• Diagnosis: Bubble ECHO 

• Presentation: usually asymptomatic, MCQ: young + DVT + stroke

• Management: usually nil, consider closure in strokes

Med Reg Notes

Background

• PFO open during fetal life to allow blood flow to bypass the submerged lungs

• Usually closes at birth during the increased right heart pressures from respiration

• 25% population prevalence

• Higher PFO rates in cytogenic strokes

• A paradoxical stroke is one caused by a DVT, through a PFO

Diagnosis

Bubble ECHO: a bubble is inserted into heart and if it flows from across the atria on ultrasound, a PFO is diagnosed (normally blood cannot flow across the atria).

Closure of PFO

• Debate around the effect of closing the PFO in those with cryptogenic strokes

• Currently isn't consensus on the criteria for closing PFOs

• The RoPE (Risk of Paradoxical Embolism) gives the probability of a stroke being associated with the PFO

For example a 50 year old with no PMH and cortical infarct on imaging has a 75% chance their stroke is from a PFO; with a 6% 2yr risk of re-occurrence.

References and Resources

1. https://pmc.ncbi.nlm.nih.gov/articles/PMC7198765/

2. https://www.mdcalc.com/calc/3902/risk-paradoxical-embolism-rope-score 

Written in 2025.