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Close to the heart

The cardiac team at St. Boniface Hospital has become the first in North America – and only the second in the world – to successfully use a stent graft to repair a tear in the ascending aorta of a patient, an approach that eliminates the need for open-heart surgery and increases the odds that the patient will survive

Danielle Laxdal and Bassett family
Dr. Siuchan Sookhoo (left) and Dr. Alan Menkis.
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How to repair an ascending aorta

BY SHARON CHISVIN
Winnipeg Health Region
Wave, July / August 2016

Tim Anderson’s experience gives new meaning to the old saying about every cloud having a silver lining.

Earlier this year, the 66-year-old retiree became the first person in North America – and only the second in the world – to successfully undergo an innovative surgical procedure to repair a tear in his ascending aorta – a tear that was only discovered during a routine chest scan to ensure his cancer was in remission.

The fortuitous turn of events is not lost on Anderson. Had he not been treated for lung cancer three years ago, he would not have been undergoing the chest scan earlier this year, and chances are the tear in his aorta would have killed him.

“I am a lucky man,” says Anderson, a tall, thin man with a shock of white hair.

Anderson’s unusual story began in 2013 when he successfully underwent radiation and chemotherapy treatments to beat his stage three lung cancer into remission.

As a precautionary measure, he was asked to periodically undergo a CT scan of his chest at Health Sciences Centre Winnipeg so doctors could make sure the tumour did not reappear. And so every six months for the next three years, Anderson dutifully turned up at HSC for the exam, and each time he was told his cancer remained in remission.

Until this past January.

“On the first Wednesday in January, I went for a CT scan,” Anderson recalls. “They noticed something.”

A second CT scan was ordered for the next day. That’s when doctors confirmed that the “something” spotted during the first chest scan was in fact a slight tear in an artery leading from his heart, known in the medical world as a dissection of the ascending aorta.

Anderson was immediately referred to St. Boniface Hospital, which is where the Winnipeg Regional Health Authority’s Cardiac Sciences Program is located. It was there that he would eventually see Dr. Zlatko Pozeg, a cardiac surgeon with the program and Director of the WRHA’s Aortic Disease Clinic.

As Pozeg explains, a tear in the aorta is no small thing. As the main artery in the human circulation system, the aorta conveys oxygenated blood from the left ventricle of the heart to all of the other body parts, with the exception of the lungs. The ascending aorta is the section of the artery that emerges from the heart, goes up towards the neck, and turns sharply to the left, arching over the heart. The descending aorta is the part of the artery that runs down through the chest and abdomen.

The aorta has three layers, and an aortic dissection occurs when the innermost layer tears, says Pozeg. Once a tear occurs, blood can propagate to a second channel, or lumen, forcing the inner layer and middle layer of the aortic wall to separate, or dissect.

If the surge of blood ruptures through the outside aortic wall, the dissection can be fatal. In fact, about 50 per cent of those who experience aortic dissection do not make it to hospital, and about 15 to 25 per cent of patients who make it to the hospital and go through the operation also die.

“It’s a lethal condition, generally speaking,” says Pozeg, who is also an assistant professor of cardiac surgery in the Department of Surgery at the University of Manitoba’s Faculty of Health Sciences.

While aortic dissections are extremely dangerous, they also are relatively rare. St. Boniface Hospital, the Region’s centre for cardiac care and a global leader in heart health, typically sees about 20 to 30 cases of the condition a year.

Most individuals who present with the condition are male, and most are over 60 years of age. Aortic dissections also are often, but not exclusively, associated with extremely high blood pressure and a history of connective tissue diseases such as Marfan syndrome. The most common feature of aortic dissection, one that affects 96 per cent of individuals who experience the condition, is severe chest or abdominal pain that comes on very suddenly.

“There’s an extreme sharp, shooting pain that happens almost instantaneously and that’s when the tear occurs,” Pozeg explains.

Anderson, however, had no pain, and no idea that he had the potentially lethal condition. But his diagnosis triggered a flurry of activity.

“I had the CT scan on the Thursday around five in the afternoon (at HSC),” Anderson says of the second scan that was used to confirm the aortic dissection. “By 10 p.m., I was in the emergency area (at St. Boniface Hospital). At 11 o’clock I went upstairs to the ICU. And then from there, one thing led to another.”

That “one thing leading to another” involved Pozeg consulting with other specialists at St. Boniface and then making some critical phone calls and arrangements.

At issue was how to go about repairing the tear in Anderson’s aorta. Normally, a tear of
this sort would be repaired by open-heart surgery, says Dr. Alan Menkis, Director of the Region’s Cardiac Sciences Program. But Pozeg proposed repairing the aorta though a procedure called thoracic endovascular aortic repair (TEVAR). 

TEVAR is a minimally invasive procedure, Pozeg explains. “It is a stent graft that we put on the inside of the aorta to stabilize the various aortic syndromes.” The stent graft is made from a special tightly woven synthetic fabric wrapped around a stainless steel framework.

“What was unusual about this case was that this occurred in the ascending aorta and we don’t usually put a stent graft in the ascending aorta,” explains Menkis, who is also Head of the Section of Cardiac Surgery at the University of Manitoba.

Although TEVAR is often used to repair dissections of the descending aorta, Menkis says dissections in the ascending aorta are generally fixed with open-heart surgery. “But,” he adds, “this gentleman had enough other problems that open-heart surgery would have been quite dangerous.”

“I felt that his poor lung function was such that it would put him at increased risk for the traditional operation,” Pozeg adds.

Fortunately, Anderson also met the very specific anatomical criteria necessary for TEVAR to be performed successfully on an ascending aorta. These criteria included his aorta being the requisite size and length for the procedure and the aortic tear being in a specific location. “You have to have enough of a landing spot,” Menkis explains, in order to perform the procedure effectively and without causing grievous harm.

“Surgery is still the gold standard for this disease,” Pozeg says, “but in patients whom we would turn down for the operation because the risk is so high, this can be a very attractive alternative.”

Adding to the complexity of the decision was the fact that St. Boniface had to get permission from Health Canada to use a special stent graft for the TEVAR procedure.

“We had to get special access from Health Canada because it is technology that has not been approved for regular use yet, because there have not been any studies done on it,” Pozeg says. “So I had to say we have this patient, it’s an emergency, this is how and why he would benefit, and they released it.”

St. Boniface also had to contact the manufacturer who makes the stent graft used in these types of procedures and have one shipped in on an emergency basis. “This particular stent graft was on the shelf in Toronto,” he continues, “and we arranged it and had it flown here immediately.” It was taken by taxi to the Toronto airport.

“They are not readily available because they are not used on a regular basis,” Pozeg says. “The company that makes them doesn’t have that many of them and they’re not in every hospital.”

By 6 p.m. Friday, Pozeg and his team at St. Boniface were ready to proceed. The TEVAR procedure performed on Anderson began with the administration of a light anesthetic. An area in his groin was then frozen and a small incision was made in that area. A needle was then inserted into the incision and passed into the artery of the groin, and a series of wires and dilators were used to progressively enlarge the hole in order to allow for the passage of a delivery catheter. This catheter contained the all-important stent graft, but in a collapsed state. The stent graft, Pozeg emphasizes, was specifically designed for the ascending aorta and is the first of its kind to be developed. 

Once the hole was wide enough, the catheter was inserted and passed up through the femoral artery to the aorta. When it reached the site of the dissection, the catheter was pulled back and the stent graft was released. The stent graft, as designed, immediately affixed to the aortic wall, thereby isolating the dissection and creating a new and secure channel through which the patient’s blood could flow unobstructed. The aortic tear was fixed.

Throughout the procedure, interventional radiologist Dr. Siuchan Sookhoo meticulously guided and monitored the stent graft’s passage and deployment using a variety of technology and radiological imaging.

“It’s important to know that I do this procedure with the interventional radiologist,” Pozeg emphasizes. “The two of us are always involved in this type of operation, and this is definitely a multidisciplinary team approach.” Other members of the team that day included a vascular surgeon, an anesthetist, nurses and radiology technicians. 

“As things get less invasive, you often need larger teams to do it because you bring in skill sets from different specialties,” says Menkis. “So for this kind of stuff, with the stent grafts and dissections and aneurysms in the aorta, having a cardiac surgeon, having a vascular surgeon, having an interventional radiologist and having an anesthetist are all required in the midst of these procedures, and it’s the collaborative work and the teamwork among these different sub-specialties that really are the key to this kind of advanced work.”

Having these specialists rely on each other for different clinical areas during a single procedure ensures that the patient gets the best care possible, he adds. “It’s a progression of what you’re already doing but because you have that larger team around you, everyone’s got an area of expertise that adds to the success of the operation.”

The team that worked on Anderson completed the TEVAR procedure in about two hours that Friday. He remained in the hospital over the weekend and returned home on Monday. Conventional surgery, in comparison, would have taken about six hours from start to finish, and, of course, would have required the opening of the chest cavity and prolonged anesthesia. It also would have meant several days of post-surgery care in the ICU for the patient and a post-operative hospital stay of about another 10 days.

“In the room I was in there was another fellow who had his chest opened, and he was into his fifth day and he was still there when I left,” Anderson recalls.

TEVAR does come with some risks, including possible injury to the blood vessels in the groin area and the rupturing of the aorta when the stent graft is deployed, but the risks inherent in the procedure are minimal compared to the risks associated with traditional invasive heart surgery – among them blood clots, lung and kidney failure, heart attack and stroke.

“By and large, the surgical risks are mitigated using this procedure,” says Sookhoo.
Pozeg had been trained in TEVAR dissections during his advanced cardiac surgery fellowship at the Hospital for the University of Pennsylvania in Philadelphia. But, while he had performed TEVAR many times on dissections of the descending aorta since joining the cardiac surgical team at St. Boniface in 2013, as well as during the five years he worked at Southlake Regional Health Centre in Newmarket, Ontario prior to that, he had never had an opportunity to use the procedure on a dissection in the ascending aorta.

Until Anderson walked through the doors of St. Boniface Hospital, the right circumstance had never presented itself.

“I honed my skills on the descending aorta, on which we’ve done lots of TEVAR, and now we’re trying to advance the field by helping patients by doing it on the ascending aorta,” Pozeg says. “I’d been waiting for the right patient to use it on.”

Placing a stent graft in the ascending aorta is not that different than placing a stent graft in the descending aorta, of which they have done a fair bit here,” Menkis adds.  “It’s just a question of them putting it in a different position, and using a completely different kind of stent graft, and maybe having a different ratchet system to deploy it.”

Anderson, for his part, was appreciative of the way in which he was kept apprised of every step of the process, including the fact that the stent graft had to come from out of town. He knew that the procedure had rarely been done, but he had full trust and confidence in Pozeg and his team.

“Because I had lung cancer, they didn’t really want to open me up,” he says matter-of-factly. “I guess if they had to, they would have, but everything seemed to work out. Dr. Pozeg explained thoroughly what he was doing and I just said, ’Well, let’s do it.’  Everything happened pretty quickly (and) everybody at St. Boniface was fantastic.”
In the months since having the procedure, Anderson has not experienced any health issues related to TEVAR. “Everything’s been really good and Pozeg has been really good,” he emphasizes.

Pozeg says the successful use of TEVAR in this case underscores the fact that he and his colleagues have the requisite knowledge, skill base and support to foster innovative techniques and advance the overall cardiac surgery program at St. Boniface Hospital and throughout the WRHA. But, he cautions, in spite of this recent ground-breaking achievement, it will still be a long time before TEVAR becomes the standard procedure to treat ascending aorta dissections.

“Way, way down the road maybe this will become more routine, but we’re not at that point yet,” he says.

His colleague Sookhoo agrees. “This is the newest field for the early part of the aorta and we need more robust designs and varieties to ensure all types of aortas can be treated,” he says.

While there has been a shift in the paradigm since the inception of stent grafts, and that shift, combined with evolving treatment and innovative technologies, may eventually make procedures like TEVAR more commonplace, that won’t happen anytime soon. When it comes to “best practices” in medicine, he adds, long-term results are needed before something can be coined a “new standard of care.”

“The stent graft technology has to be advanced and improved upon and these things often go in stages,” Pozeg adds. “First, we test the safety and feasibility and then we test the long-term function and outcomes.”

The experience with Anderson, he adds, proved that it was feasible, it can be done, and it was safe. “So those were two very early steps we need to establish before we move on and use it regularly.”

At the same time, Anderson’s experience also reaffirmed that St. Boniface Hospital is a global leader in innovative cardiac care. “Although we are quite small,” Sookhoo says, “we are definitely in the forefront along with our bigger brothers and sisters in the rest of Canada and the (United States.)”

Being the first health centre in Canada, and in fact in North America, and the second health centre worldwide, to successfully perform this particular procedure for this particular condition has been a great source of satisfaction, Menkis admits. But the fact that his team was able to achieve this milestone did not come as a surprise to the director. The achievement, he says, is a reflection of his department’s long-standing commitment to excellence and innovation, and to its openness to try new approaches and creatively work together.

“If you think about what’s best for the patient, rather than what you are familiar with doing, then with the right backup and team and co-operation and collaboration, you can make these things successful,” he says. “Really, the secret is bringing the right people with the right technology and the right facility around the patient, and that’s what we try to espouse in all aspects of our program.”

The use of TEVAR on Anderson’s ascending aortic dissection was just one manifestation of this co-operative and collaborative approach.

“We helped somebody who would have been in a great deal of trouble in not a very long period of time,” Menkis adds. “Having the stars aligned with the right team and patient, and the right circumstance and the right technology available to us in rather short order was terrific,” says Menkis. 

Not just for St. Boniface Hospital, but for Tim Anderson as well.

Sharon Chisvin is a Winnipeg writer.

Wave: November / December 2015

About Wave

Wave is published six times a year by the Winnipeg Health Region in cooperation with the Winnipeg Free Press. It is available at newsstands, hospitals and clinics throughout Winnipeg, as well as McNally Robinson Books.

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