Toronto (Aug. 23, 2007) - Peter Munk Cardiac Centre clinicians at Toronto General Hospital repaired a common heart defect linked to stroke with an implant or patch that encourages the heart's own healthy tissue to grow and heal itself, and which then disappears within months.

In a North American first, Peter Munk Cardiac Centre clinicians used a novel "bioresorbable" device made of collagen and an alloy frame to treat a patient with patent foramen ovale (PFO), a common congenital heart defect. It's a small hole in the muscular wall separating the heart into the upper right and left sides. Normally, the PFO closes at birth, but in about 30% of the population, it does not.

"This type of technology is futuristic, it helps the heart heal itself and then the majority of the device gets absorbed by the body, so there is no barrier to future therapies," said Dr. Eric Horlick, the lead interventional cardiologist at the Peter Munk Cardiac Centre who performed the first procedure in North America on July 13, 2007. "By placing another type of permanent implant we effectively close the PFO, but lose access to the left atrium for further therapies that could impact heart rhythm disorders or valvulvar heart disease. That is an important consideration". Dr. Horlick is also an Assistant Professor of Medicine at University of Toronto.

Derwyn Miller, 59, has had one stroke, and was recently found to have an embolism which blocked a blood vessel in his left eye. This was an especially critical event as he is already blind in the right eye. Tests revealed that he had a PFO, and was facing either being on blood thinning medication for life or receiving an older version of an implant, which would remain permanently in his body. However, when offered the chance to be the first North American patient to receive the new technology, Derwyn eagerly accepted. The procedure took about half an hour, with Derwyn going home the same day. Since then, three other patients have had the procedure and all are doing well.

"I was very happy to be the first patient to have this done. It was critical for me to reduce the risk of getting blood clots in my good eye, " said Derwyn, adding that he was surprised at how quickly he recovered from the procedure.

Usually, patients with PFO have no symptoms, but among young patients who have had a stroke of undetermined origin, the PFO may be implicated as the cause. Under certain conditions of increased pressure inside the chest (such as squatting, coughing or sneezing), blood may travel from the right upper chamber to the left upper heart chamber. If there is a clot or other type of particle in the blood in the right side of the heart, it can easily cross the PFO, enter the heart's left side, and then travel out of the heart to the brain, causing a stroke, or into a coronary artery, causing a heart attack.

Until now, these heart defects were usually treated with permanent implants or with blood thinners.

In the new procedure, Dr. Horlick and the multidisciplinary team of interventional cardiologists, nurses, and technologists used the BioSTAR implant to patch the opening in Derwyn's heart. The device, manufactured by NMT Medical of Boston, encourages the heart's own tissue to grow over it, closing the hole and absorbing the device's collagen mesh. To date, the device has been used in Europe, and now in Toronto through the Peter Munk Cardiac Centre. It is in clinical trials in the U.S. and not yet commercially available for patients there.

"The Peter Munk Cardiac Centre is one of the world's leading training centres for new technologies to treat structural heart disease," said Dr. Horlick, adding that "We are expert in interventional technologies and repairs that once required open-heart surgeries and which now allow the patient to recover faster and more easily."

During the procedure, a catheter or tube is threaded from the groin through a vein to the left atrium of the heart. A small delivery catheter that holds the device is slipped into this tube and advanced to the septum, the wall which separates the heart into the left and right sides. The implant is pushed through the hole in the septum and is opened out like an umbrella. The device is then retracted until the umbrella-like device covers the hole. A second patch is deployed on the other side of the septum wall so that the hole is firmly plugged on both sides. With time, most of the device dissolves and is covered by natural heart tissue. The procedure is monitored by a sophisticated, miniaturized real-time echocardiogram performed from the inside the heart , which displays the beating heart, including the chambers and the major blood vessels, helping the cardiologist to accurately guide and place the device and assess the effect of placement. Dr, Horlick adjusts and interprets the echo in real time as the procedure progresses.

About Toronto General Hospital

Toronto General Hospital is a partner in the University Health Network, along with the Toronto Western Hospital and the Princess Margaret Hospital. These research hospitals are affiliated with the University of Toronto. The scope of research at Toronto General Hospital has made this institution a national and international source for cardiovascular discovery, education and patient care, as well as for its innovations in transplantation, surgical innovation, infectious diseases, diabetes and genomic medicine. In addition, the Peter Munk Cardiac Centre at Toronto General Hospital trains more cardiologists and cardiovascular surgeons than any hospital in Canada.

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Email: UHN.News@uhn.ca

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