Breakthrough discovery in treating narrowed arteries

A breakthrough discovery by Heart and Stroke Foundation researcher Dr. Michael Kutryk that harnesses the body’s own natural defenses to fight narrowing of the arteries has been recognized as “a glimpse into the future” and “potentially one of the biggest advances in cardiology to date”.

Dr. Kutryk was presented with the Canadian Cardiovascular Society’s Young Investigator Award last night at the Canadian Cardiovascular Congress 2004 in Calgary, co-hosted by the Society and the Heart and Stroke Foundation of Canada.

“We’re proud to recognize talented researchers in the early stages of their careers, and look forward to many more years of great work from Dr. Kutryk,” says Dr. David Johnstone, President of the Canadian Cardiovascular Society.

A stent is a small, stainless steel mesh tube inserted as a “scaffolding” to open up plaque-blocked coronary arteries and to keep them open. But in the first six months of treatment, between 15% and 40% of patients with a stent experience renewed narrowing of the arteries and blocking of the stent, says Dr. Kutryk.

This in-stent re-narrowing is called restenosis. It is caused by the formation of extensive scar tissue on the inside wall of the artery where the stent is located. To date, the only solution has been to coat the surface of stents with powerful drugs prior to inserting the stent. Although these drugs can prevent restenosis, they inhibit the growth of the endothelium, which is the innermost cell layer of the blood vessel. A healthy endothelium is necessary for the maintenance of a healthy blood vessel and the lack of endothelium prevents full healing and can result in life-threatening blood clots.

Now, both plain stainless steel stents and their drug-eluting cousins may be on the way out, according to Dr. Kutryk. “The stent we developed with the help of our Heart and Stroke Foundation funding promotes healing of the artery wall and prevents blood clots. In fact, it completely heals blood vessels within 48 hours,” says Dr. Kutryk.

Dr. Kutryk coats his stents with a laboratory-designed antibody that captures naturally occurring endothelial cells that we all have in our circulating blood. “Within minutes of inserting the stent, the antibodies have grabbed endothelial cells from the bloodstream and completely coated the stent,” explains Dr. Kutryk.

“This is really exciting work that could make a big difference in the use of stents in Canada and around the world,” says Dr. George Honos, spokesperson for the Heart and Stroke Foundation and a cardiologist.

Clinical trials for safety and efficacy have been conducted on patients in Holland, Belgium and Germany. A Canadian trial of 400 patients is set to begin next year.

Dr. Kutryk is also currently being funded by the Heart and Stroke Foundation to develop a bio-degradable stent that will simply “disappear” after it has healed the artery or blood vessel. “There are an enormous amount of applications for this technology. The enquiries are coming in from cardiologists all over the world,” says Dr. Kutryk.

Much of the interest is centered around the anti-blood clotting capability of the new endothelial surface coatings produced by the “snatch and grab” action of the antibodies.

“For people with extensive coronary artery disease that cannot be treated using coronary stents, we designing synthetic, non-clotting, vascular grafts which surgeons can just order up from the hospital pharmacy. That would replace current techniques of transferring one of the patient’s veins from the leg into the heart. This could cut the time for bypass surgery in half,” he says.

Also on Dr. Kutryk’s research agenda are endothelial cell coated neurological clips and mechanical heart valves. In both of these procedures blood clotting is a constant risk that must be kept at kept at bay by drugs. These drugs can also cause side effects, for some patients including fatal hemorrhages. Dr. Kutryk’s work could lead to less pain for patients, shorter hospitalizations and significant savings to the Canadian healthcare system.