PFO/ASD closure
Overview
A PFO (Patent Foramen Ovale) and an ASD (Atrial Septal Defect) is where there is a hole in the septum between the right and left atria.
PFO is a flap which tends to close after birth, although remains patent in ~25% of the population, however for the majority of patients with PFOs there is no clinical significance.
-Foramen ovale is patent during fetal devlopment in order for blood to bypass non functional fetal lungs
An ASD is a congeintal abnormality of the septum. This allows for blood to flow from the left to right atria or vice versa, resulting in mixing of arterial and venous blood (shunt).
-A right to left shunt is considered more severe as it results in de-oxygenated blood being pumped throughtout the body.
If there is significant strain on the heart, the PFO or ASD may need to be closed.
This can be done using TOE with x-ray, where a catheter is passed from the right atrium to the left atrium, and a closure device is deployed to expand and straddle both sides of the hole.
Procedure
Equipment
-
Venous sheaths - usually starts with 7F which can be upgraded to delivery system sheath size
-
Amplatzer catheter
-
Septal occluder/ASD closure device (nitinol wire mesh filled wth Dacron fabric)
-
sizing balloon may be used
Procedure
-
Done under GA
-
Venous access and catheter is inserted into RA (pressure sample recorded)
-
Catheter crosses into the LA (pressure sample recorded)
-
A sizing balloon catheter may be used to measure size of hole (this may be done on TOE too)
-
An appropriate sized device is chosen, prepped and deployed across the septum.
-
Successful device deployment is confirmed by TOE (colour doppler) and contrast/bubble injections
