PFO leading to shunt physiology

1. Noon Conference
Owen Thompson, MS4
09/13/2018

2. © 2016 Virginia Mason Medical Center 2
Objectives
Patent Foramen Ovale
• Context of R to L shunt
• Epidemiology, Embryology
• Clinical presentation
• Diagnosis
• Treatment
• Illness Scripts

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Context
Altitude
Normal
Hypoventilation
Diffusion
“Dead Space”
Shunt
Causes of Hypoxemia
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Context
Shunt
(Anatomic vs Physiologic)
Intracardiac
PFO
ASD
VSD
Sinus of Valsalva Rupture
Extracardiac
Pulmonary AVM
Hepatopulmonary Syndrome
Peds
Truncus Arteriosis
Transposition of Great Vessels
Tricuspid Atresia
Tetralogy of Fallot
Total Anomalous Pulmonary Venous Return
Eisenmenger

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Epidemiology:
• Autopsy, community TTE studies: 25%
• Cryptogenic stroke cohorts: 40%
• Female siblings of PFO patients: 77%
• Odds Ratio 9.8
Embryology:
• Flap fusion complete by age 2yo
• Associated:
• Other ASD
• Atrial Septal Aneurysm
• Chiari Network
• Ebstein’s
Patent Foramen Ovale
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Question
A 47yo woman with past medical Hx of HTN and GERD presents
with acute onset vision loss, confusion, dizziness and paresthesias.
She is found to have a PCA infarct. Workup is negative for large
artery atherosclerosis, cardioembolism, or small-vessel occlusion,
but she is found to have a PFO by TTE. What is the most
appropriate next step?
A) PFO closure
B) DVT/VTE evaluation
C) Antiplatelet therapy
D) Anticoagulation

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Clinical presentation
7
Mostly asymptomatic!!
Most important:
• Cryptogenic Stroke
• 20-40% of all ischemic strokes
• Migraine / Vascular Headache
• Platypnea-orthodexia syndrome
• Decompression Sickness  Air Embolism
Dyspnea
Desaturation
A-Okay

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Diagnostic criteria
Ultrasound:
• All modalities use agitated saline (bubble) contrast
• 3-5 beat delay more consistent with AVM
• Physiologic R  L shunting
• early ventricular systole
• Valsalva release
• Cough
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Study Doppler Visualization Sn
TTE Y +
TEE Y Y +++
Intracardiac echocardiography Y Y +++
Transmitral doppler +++
Transcranial doppler +
GRADE BUBBLES
0 0
1 1-30
2 30-100
3 >100

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Treatment
9
Incidental?
Nothing
Cryptogenic Stroke?
2017 Practice Change (after extensive stroke workup):
• <60yo
• Cryptogenic nonlacunar ischemic stroke Percutaneous Device
• PFO with R to L bubble study
vs. antiplatelet therapy alone
Side effects: new-onset atrial fibrillation,
hematoma, device migration/embolization

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Illness Scripts
10
ASD Pulmonary AVM
Pathophysiology Failure of embryologic closure (usually by 2yo)
Most (>90%) due to HHT / Osler Weber Rendu.
Also hepatic cirrhosis, cancers…
Epidemiology
Very common (25% incidence)
Less commonly symptomatic
Enriched in cryptogenic stroke cohorts
VERY uncommon (3 in 15,000 autopsy studies)
2:1 F:M
Time course Variable
HHT: Symptoms develop with age, epistaxis first
(teens), AVMs likely present in childhood
Clinical
presentation
Cryptogenic Stroke (paradoxical embolus)
Migraine / Vascular headache
Platypnea-orthodeoxia syndrome
Decompression sickness , air embolism
Dyspnea, HEMOPTYSIS, chest pain, cough,
stroke, brain abscess, murmur, polycythemia,
pulm HTN, clubbing/cyanosis,
Platypnea-orthodeoxia syndrome
Symptoms usually in 4th-6th decade
HHT: epistaxis, mucocutaneous telangiectasias,,
brain abscess. Symptoms in 20s
Diagnostics
TTE
TEE
Intracardiac echo
Transcranial doppler
Transmitral doppler
TTE with bubble contrast
Chest CT
Pulmonary angiography
MR angiography
Therapeutics Percutaneous closure Embolization

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Acknowledgements
- Zach Mattes
- Cheyenne Enevold
- Meghan Caballero
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