You can learn a lot form your siblings. In this case, I learned How to Save a Life. My brother, Brian Archer (Queen’s Meds ’88) is a radiologist at the Regional Hospital in Saint John, New Brunswick. For the past 5 years, an interprofessional team has quietly been replacing heart valves in patients who have a valve disease called Aortic Stenosis. What is remarkable is that this is done without surgery, with the valve being delivered to its resting place on a catheter inserted through the femoral artery. This procedure is called TAVI. Their program reflects a collaboration between cardiologists, radiologists, cardiac surgeons, X-ray technicians and nurses. It has helped over 70 patients to achieve a better quality and longer duration of life. I invite you to watch the New Brunswick TAVI team doing a TAVI (accompanied by the Denver rockers The Fray):
The most remarkable scene is at the end of the video. It’s not the number of people in the room - although that’s remarkable too - it’s the fact that in many hospitals, radiologists, cardiologist and surgeons are opponents, rather than partners. This is what patient-centered care looks like (note the patient-he’s the one in the middle). Brian, I say with some pride, is the one with the black hat. Aortic stenosis is a common disease. Although there are many causes of aortic stenosis (narrowing of the heart’s main outlet valve), most cases occur in the elderly, and involve calcification of the aortic leaflets. The normal cross sectional area of an aortic valve is ~3-4 cm2. In aortic stenosis, the blood from the left ventricle must exit via an orifice that is often reduced to one-fifth this size (i.e. 0.6 cm2). This causes the heart muscle to hypertrophy and eventually fail. Patients complain of shortness of breath, chest pain and may suffer syncope (passing out). The cure? Aortic valve replacement. This operation is advanced in its evolution and is done via a sternotomy using cardiopulmonary bypass. In good surgical candidates, operative mortality rates of 1-3% are expected. However, aortic stenosis is increasingly a disease of the elderly; many patients are over age 80 years and often they have comorbidities. In this growing cohort, surgery has a higher, and often prohibitive risk. Much as coronary angioplasty has become a mainstream option for managing coronary disease - not replacing coronary artery bypass grafting but certainly being used much more commonly as a therapeutic strategy - so might a percutaneous strategy for valve replacement open up therapy to a new high-risk group of patients. One interesting fact: we don’t know why patients develop aortic stenosis. Many patients retain a normal aortic valve even into their 90s. A recent genome-wide association study from McGill University identified a single nucleotide polymorphism (variation in the gene sequence by one nucleotide) in the lipoprotein, LpA, predicts increased risk for the development of aortic stenosis. This study suggests genetic differences may predispose certain individuals to calcific aortic stenosis.
Transcatheter aortic heart valve (TAVI, also called TAVR) is a procedure with strong Canadian roots. Dr. John Webb at the University of British Columbia and his team pioneered this technique, and since 2005 have implanted over 500 such valves. The procedure has been tested and validated. It is usually done in patients who, because of age and infirmity are not candidates for conventional aortic valve replacement, tend to be older and sicker. As a result, the risks - mostly stroke and problems with damaged blood vessels - are significant. Nonetheless, in a landmark paper in the New England Journal of Medicine, TAVI was shown to be feasible and superior to conservative management in these high-risk elderly patients. A total of 358 patients with aortic stenosis who were not considered to be suitable candidates for surgery underwent randomization at 21 centers (17 in the United States). At one year, the rate of death from any cause (Kaplan–Meier analysis) was 30.7% with TAVI, as compared with 50.7% with standard therapy. The 20% reduction in death is significant and subsequent studies have corroborated the feasibility of this technique. It is probable that with new valves and improved techniques, TAVI will eventually become available to lower risk patients and indeed that move is underway. In a large study of intermediate risk patients TAVI and surgery performed similarly…albeit each with their own adverse outcome profile. Our new program at Queen’s began in February 2013. The picture (left) shows the inflation of the valve, complete at the valve's lower end and in process higher up in the aorta.
As in New Brunswick, it is collaboration. It bodes well for the program that when I asked the lead cardiologist, Dr. Paul Malik (left; Dr. Darrin Payne at right), for a list of the members of the team I receive the following prompt reply:
Even this list is not complete…the program had support from the Chief of Cardiology, Dr. Chris Simpson and the Dean Richard Reznick. Launching the pilot program required commitment from our regional leadership, notably Paul Huras. This is a reminder that smaller centers with great teams can do great things….provided we keep the patient in center! So into the fray we go.