An ASD, is a congenital defect in the septum that allows blood flow between the two upper chambers (atria) of the heart. An ASD is commonly known as a "hole in the heart." This communication results in the continuous mixing of arterial and venous blood known as a "shunt". The amount of shunting present dictates the hemodynamic significance and can translate to progressive symptoms of shortness of breath due to overload of the right side of the heart.
A PFO is physiologically similar, but consists of a "flap" covering the hole which allows intermittent communication between the two chambers. All babies are born with this flap present, but in the majority of individuals it permanently closes about four weeks after birth. In various observational studies, this flap has been noted to remain patent in as high as 20% of the population. In most individuals, the presence of a PFO does not translate to any symptoms at all.
ASDs and PFOs have been now recognized to be associated with increased risk of stroke, due to their ability to allow blood clots to cross from the venous circulation to the arterial circulation. Referred to as paradoxical systemic embolization, these blood clots can travel to the arterial circulation of the brain, causing an obstruction of blood flow which results in a stroke.
Traditionally, these septal defects have required open-heart surgery to close this abnormal communication between these two chambers of the heart. A revolutionary treatment option for the closure of ASDs and PFOs utilizes a percutaneous device delivered through a vein, therefore avoiding the need for invasive surgery. The occluding device uses the shape memory of Nitinol (an alloy of nickel and titanium) wire mesh that conforms two flat discs to fit the defect size. This minimally invasive procedure, performed by an interventional cardiologist, typically takes place in a catheterization laboratory where the device is delivered to the heart through a small catheter using x-ray and echocardiography. The recovery time for this procedure is much less than the traditional surgical route and usually only requires an overnight stay in the hospital.
If you have experienced a stroke and/or have been diagnosed with an atrial defect, please consult your physician to determine if this procedure may be beneficial for you.