Dr. Maral Ouzounian, cardiac surgeon at UHN’s Peter Munk Cardiac Centre was the Principal Investigator in a study that compared the two leading options for young to middle-aged patients facing replacement of their aortic valve. (Photo: Peter Munk Cardiac Centre, UHN)

A Peter Munk Cardiac Centre-led study that compared the two main surgical options to replace diseased or failing aortic valves in young and middle-aged patients was recently published in the journal Circulation. 

The aortic, tricuspid, mitral and pulmonary valves are the four main valves in the heart. Each valve acts as a key conduit for controlling blood flow through the body. 

The study yielded some surprising results, expected to impact both patients within a defined age group who face replacement of their aortic valve, and physicians.

The study's Principal Investigator is Dr. Maral Ouzounian, cardiac surgeon, Peter Munk Cardiac Centre, University Health Network and leading expert in aortic disease and scientist within the Peter Munk Centre of Excellence in Aortic Disease.

UHN News talked to Dr. Ouzounian about the impetus for the study, which compared 208 matched pairs of patients, each of whom had been followed over many years following aortic valve replacement surgery.

Why was this study necessary?

The study was really done to answer a fundamental question: What is the best option for young to middle-aged patients who need an aortic valve replacement?

If you are facing aortic valve surgery, you really have one of two options. If your aortic valve leaflets are normal, your aortic valve could be repaired. Alternatively, if your aortic valve is very diseased, then it is not reparable, in which case you need a valve replacement.

Describe the options for young or middle-aged individuals requiring an aortic valve replacement?

​​If you are facing aortic valve replacement surgery, you have one of three options.

The first is a mechanical aortic valve, of which the benefit is that it's durable and will last a long time. The downside is it requires lifelong anti-coagulation – through coumadin or warfarin – to keep the blood at the right thinness.

The second option is a biological valve such as a pig or cow valve. The benefit there is you don't need warfarin, you can just take Aspirin for those valves. However, particularly in the population of 30 - 40-year-olds, these valves are not durable, so they are not really an appropriate option for very young patients.

The third option is the Ross procedure.  The Ross procedure is a technique whereby we take the patient's own pulmonary valve and we excise their diseased aortic valve. We place their own pulmonary valve into the aortic position and we replace their pulmonary valve with a cadaveric pulmonary valve or what's called a homograft.

The Ross procedure has been in use for many, many years, but it's a technically a more complex operation than a straightforward mechanical aortic valve. And so, uptake of the Ross procedure across the world has really waxed and waned, and has stayed at relatively low rates. It's only done in certain centres.

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