In a symposium called “Evolution in Cardiovascular Diagnosis and Therapies in Canada 2000-10,” leading figures discussed the changes seen over the previous decade in prevention, imaging, interventional cardiology and surgery. Two of those leading figures were Heart Institute physicians.
Dr. Andrew Pipe, Chief of Prevention and Rehabilitation, kicked things off with a survey of changes in the prevention landscape. Smoking—the single most effective intervention for reducing disease risk—has seen major successes thanks to new drug therapies and smoke-free legislation in many regions. With these efforts, the smoking rate has dropped to 15 per cent of the Canadian population.
Cholesterol and blood pressure are now better controlled through improved treatment of those with high levels. Prescriptions for statins have quadrupled over the past 10 years. The incidence of hypertension, though, is increasing with an aging population, as is the incidence of diabetes. Diabetes and obesity are of particular concern with 25 per cent of Canadian adults and 10 per cent of Canadian children now obese.
On the imaging front, the Heart Institute’s Dr. Rob Beanlands offered a “Top 10 in the Last 10 Years” list that highlighted emerging issues and capabilities. Various modes of imaging have seen improvements or established themselves over the past decade. Nuclear cardiology has seen a number of technical improvements.
It is important to note that the Heart Institute has been a leading innovator in nearly every area highlighted by the presenters.
Software detector advances have reduced radiation doses, and improved image quality for SPECT (single photon emission computed tomography) scanners and the ability to quantify blood flow with PET offers promise for use in microvascular diseases. CT angiography has had a major impact in reducing wait times and offering prognostic value. MRI has emerged and will play a greater role to come. Echocardiography has also seen a number of improvements in terms of 3-D imaging, quantifiable methods and mobility in the form of handheld devices.
Significant issues around imaging have also become widely recognized. The shutdown of the Chalk River nuclear reactor and the subsequent medical isotope shortage highlighted the high level of risk in the system and led to efforts to develop alternatives that can be produced without reactors. The related issue of radiation doses that patients are exposed to has come to the fore in the past few years and will be the focus of technological advances to come. Dr. Beanlands concluded that, if radiation levels can be reduced sufficiently, CT angiography could become the standard test for coronary artery disease.
Other speakers addressed interventional cardiology and surgery. Major changes in interventional cardiology have centred on a few areas. Primary coronary intervention (PCI) has changed substantially with the evolution of stents from bare metal to drug eluting to the coming era of resorbables, along with the advent of improved anti-platelet therapies to reduce the risk of clotting. The rapid delivery of PCI thanks to the introduction of STEMI heart attack protocols has significantly cut death and stroke rates.
Strong clinical trial evidence has helped to clarify when stenting versus bypass surgery is the way to go. Stenting is equally effective for the least complex cases, while bypass has the clear edge for more complex cases. There has also been growing collaboration between surgeons and cardiologists with the emergence of percutaneous valve replacement techniques. Transcatheter aortic valve insertion (TAVI) has become an effective alternative for patients who are not good surgical candidates. The mitral valve will likely be the next target for percutaneous replacement.
For surgery, there has been a general decline over the past 10 years in bypass procedures as less complex cases end up in the catheterization lab. But other types of procedures are growing, and the patients that surgeons are seeing are increasingly older and have more co-morbidities. Despite this, mortality rates continue to fall. This is due, in part, to increased accountability and oversight in the form of report cards and outcomes tracking. Technical advances have also been a major theme. Minimally invasive techniques are reducing recovery times, and the TAVI valve replacement offers hope for patients not suited to open heart surgery.
It is important to note that the Heart Institute has been a leading innovator in nearly every area highlighted by the presenters. In prevention, the Ottawa Model for Smoking Cessation is used across Canada. In imaging, the Institute is an international leader in PET, CT and isotope research. In interventional cardiology, Dr. Michel Le May has pioneered the STEMI protocol responsible for cutting heart attack deaths in half. And in surgery, the Heart Institute has been a Canadian leader in TAVI, and Dr. Marc Ruel has led the development of minimally invasive surgical techniques.