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Updated: May 23, 2026
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Closure of a Patent Foramen Ovale (PFO): An Intervention Sequence
Published on: December 23, 2022
Patent foramen ovale, dialysis and microembolization
Sudhakar George1, Stephen Holt, David Hildick-Smith
1Department of Cardiology, Brighton and Sussex University Hospitals, Brighton, UK. sudhakar.george@nhs.net
Nephrology (Carlton, Vic.)
|April 11, 2012
Summary
Haemodialysis (HD) circuits generate microemboli, but this study found no evidence of cerebral microembolization in HD patients, even those with a patent foramen ovale (PFO). Microemboli were detected in arteriovenous fistulae during HD, but did not reach the brain.
Area of Science:
- Nephrology
- Cardiology
- Neurology
Background:
- Haemodialysis (HD) circuits are known to produce microemboli.
- A patent foramen ovale (PFO) may facilitate intracardiac shunting of these microemboli to the cerebral circulation in HD patients.
Purpose of the Study:
- To investigate the presence of PFO in HD patients.
- To confirm microemboli generation during HD.
- To detect cerebral microemboli in HD patients using transcranial Doppler scanning.
Main Methods:
- Bubble contrast transthoracic echocardiography was used to identify PFO in HD and peritoneal dialysis patients.
- Arteriovenous fistulae were interrogated to confirm microemboli production during HD.
- Transcranial Doppler scanning of the middle cerebral artery was performed before and during HD.
Main Results:
- A PFO was identified in 21.3% of patients (12/51 HD patients, 5/29 PD patients).
- A significant increase in microemboli was observed in draining arteriovenous fistulae during HD compared to before HD (P = 0.012).
- No evidence of cerebral microembolization to the middle cerebral artery was detected during HD in either group.
Conclusions:
- Microemboli are produced in the arteriovenous fistulae during HD.
- Despite PFO presence, no cerebral microembolization was detected in the middle cerebral artery during HD.
- These findings differ from previous studies reporting carotid circulation microemboli during HD.
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