Before birth the foramen ovale allows mixing of blood in the collecting chambers of the foetal heart. After birth as the lungs start to function, this flap of tissue closes and in the first few years of life in most people it fuses permanently. In 5 to 15% of otherwise normal people the flap of tissue remains open, in the majority of people the resulting defect is small and of no significance. It is likely that in normal people there is frequent development of blood clot in the large veins of the legs and pelvis, usually they are broken down when the blood carries them to the lungs. However in some certain circumstances the pressure in the right side of the heart exceeds that on the left (coughing, straining, lifting etc) and clot can bypass the lungs and lodge in the arteries in the brain causing stroke via the PFO.
The presence of a Patent Foramen Ovale (PFO) (potential hole in heart) can allow passage of blood clot, bubbles or chemicals from the right to the left side of the heart which can cause stroke and other neurological conditions and decompression symptoms (when SCUBA diving).
This procedure can be performed under local anaesthetic with an ICE ultrasound probe as described above. Dr. Shapiro’s preference is to use a general anaesthetic (as the ASD closure), as this allows the use of the techniques of three dimensional TOE. The images obtained via 3D, give much better demonstration of the anatomy and allow much more precision in closure.
Sometimes Dr. Shapiro uses similar devices to the ASD closure but a variety of others are available and each has it specialist use.
Dr. Shapiro runs an annual training course in Cambridge to discuss which device suits which hole.
Dr. Shapiro has performed approximately 800 cases of PFO closure since 1992. The audit data shows no deaths or serious complications including device displacement.
2D echo showing a pfo in a young patient who had suffered a stroke.
Xray images showing deployment of AGA PFO closure device.
Figure showing PFO device in the left atrium by 3D echo.
Patients are usually treated as a day case and return promptly to normal activity. Often a six month course of aspirin and clopidogrel is prescribed.
Who needs PFO closure?
This is a rather more difficult decision , younger patients with a definate stroke with no other cause and a widely open PFO and also possibly an septal aneursym are the most certain.