When a doctor told May Brown, at age 90, that her aortic valve was failing, the former Vancouver city councillor feared she was done for.
Open-heart surgery wasn’t an option because of scar tissue left two decades earlier after radiation treatments for cancer of the esophagus, she said.
Ms. Brown, a dedicated outdoorswoman and Order of Canada honoree, began to tire easily and became short of breath. “I could see that I was going downhill,” she said.
Fortunately, she was referred to John Webb
Pioneered by Dr. Webb at St. Paul’s Hospital
Ms. Brown underwent the procedure in October, 2010. By the second day she was on her feet, and within five days she was back at home and ready to start a walking routine. “After a month I was feeling very well,” she said. “This was really like a new lease on life.”
Dr. Webb developed the minimally invasive procedure in 2005. Since then, colleagues in more than 25 countries have performed a total of 50,000 aortic valve replacements using his technique.
In a 2010 editorial in the journal of the American Heart Association
The procedure, known as trans-catheter aortic valve implantation (TAVI), eliminates the need to open the chest, saw through the breastbone and put the patient on a heart-lung machine.
Compared with open-heart surgery, patients who undergo TAVI tend to recover faster, Dr. Webb said, adding the success rate among high-risk patients is more than 95 per cent.
“Almost everybody can have their valve done this way,” he said.
The trans-arterial approach was the main innovation of the St. Paul’s Hospital team, which built upon techniques developed elsewhere. There was no “aha” moment, Dr. Webb said. “It was an incremental thing.”
The method allows Dr. Webb to replace aortic valves in up to four patients a day. The majority are not candidates for surgery because of previous procedures or advanced age, he said.
Aortic valves deteriorate with age. The tissue begins to stiffen, preventing the valve from opening fully. “It’s a wear-and-tear thing,” Dr. Webb explained.
The aortic valve has three triangular leaflets that fit together like the Mercedes Benz logo’s three-pointed star. Dr. Webb uses a similarly shaped valve made of bovine tissue that is sewn to a circular metal mesh called a stent.
In its compact form, the stent has a diameter of seven millimetres, about the same as a milkshake straw. The stent is fitted behind a small balloon on a catheter that enters an artery through an incision in the patient’s leg. Inside the body, the stent is pulled over the balloon to prepare for expansion at the aorta above the heart’s left ventricle.
The cardiologist makes two smaller incisions in the patient’s other leg to insert a tube to inject X-ray dye and a wire that sends electrical stimuli to pace the heart.
While the patient is asleep, a small ultrasound probe is put down the throat and into the stomach to provide visuals as the cardiologist moves the new valve into place.
