Med Device Monday: Preventing Recurring Strokes

This fall, FDA announced the approval of a new medical device that can help avoid recurrent strokes in certain patients. Strokes happen when blood supply to the brain is cut off or drastically reduced, causing damage by killing brain cells. The most common type of stroke is the Ischemic stroke, which happen when a blood vessel to the brain is obstructed. 

Plaque build-up in arteries can narrow narrow the vessels, and it can also break loose and lodge in smaller vessels, blocking blood's path in the brain. Blood clots can cause these blockages as well. When this happens, these pieces of debris are known as emboli. The AMPLATZERPFO Occluder from St. Jude Medical is a new medical device meant for patients aged 18-60 years who experience repeat Ischemic strokes due to a hole in their heart and the subsequent blood clot emboli.

 Photo from heart.org.

Photo from heart.org.

Patent foramen ovale (PFO) is a small opening between the upper chambers of the heart. This hole, or flap, is a normal part of fetal development and it typically closes in infancy. Many people for whom it doesn't close will never even know: it is often asymptomatic unless and until it causes other problems. Per the Mayo Clinic, the tip-offs can include migraines with aura and (you guessed it!) unexplained strokes: "Although it's not uncommon to have a patent foramen ovale, most people with the condition never know they have it. A patent foramen ovale is often discovered during tests for other problems...most people never need treatment for this disorder." Strokes happen for people with PFO because the open flap allows blood clots to form and be passed from the right to left side of the heart and into the blood stream. 

St. Jude Medical explains: "Normally in a developing fetus, the foramen ovale allows oxygenated blood from the placenta to bypass the lungs. This small, flap-like opening typically closes shortly after birth. When this flap remains open, or "patent", it is referred to as a PFO. A PFO can potentially allow dangerous clots to pass from the right side of the heart to the left, travel up to the brain and cause a stoke. The AMPLATZER PFO Occluder is the only device approved in the United States for PFO closure and has been shown to lower the risk of stroke by sealing the unwanted hole between the left and right chambers of the heart." 

 Photo from sjm.com.

Photo from sjm.com.

This less-invasive procedure is a good alternative to open-heart surgery (a hot topic around here lately!), and also would be a replacement for anticoagulant or antiplatelet therapy. FDA's description of the device reads "The device is made of two connected circular, self-expanding, nickel-titanium (Nitinol) discs that contain thin polyester fabric. ...To place the device, a physician first inserts a delivery catheter through a vein in the leg until it reaches the heart. The physician then advances the AMPLATZER PFO Occluder through the delivery catheter and opens the left disc in the left atrium and the right disc in the right atrium. The physician then separates the PFO occluder device from the delivery catheter, removes the delivery catheter from the body, and leaves the occluder device permanently implanted in the heart. The two connected discs close the PFO. Over time, a thin layer of tissue covers the device."

The image above is of the AMPLATZER™ PFO Occluder, and while the video below is not, it is quite similar and the procedure for placing it is essentially identical to that shown on the St. Jude Medical website.