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Surgical Treatment of Hypertension

Renal denervation has recently been reintroduced as a technique for dealing with refractory hypertension. George Oreopoulos is the surgical member of the Renal Denervation Project led by nephrologists Sandy Logan and cardiologist John Floras at the University Health Network and Mount Sinai Hospitals. The project is reexploring an approach that was introduced in the 1950s to denervate the kidney. In the earlier versions, this was accomplished by dividing the renal artery. The current technique involves hyperthermic interruption of the nerves to the kidney, which travel in the adventitia of the renal arteries. This is accomplished by heating the artery in a controlled burn for two minutes at multiple sites.

George got into this project because of his experience in renal artery surgery and stenting. He is a vascular surgeon with interventional radiology training. The project at the University Health Network is the first in Canada. The fourth patient is currently undergoing treatment. "The radio frequency Symplicity catheter manufactured by the Medtronic company is actively deployed and often used elsewhere in the world. Preliminary experience with this technique has been promising. Patients who are on six medications and still have unacceptably high blood pressure have been brought under satisfactory control with reduction in their medication and acceptable systolic pressures. It does not make them medication free. However, the patients who are currently treated are those with the most difficult form of the disease, requiring high doses of multiple medications. The early trials with the catheter have shown promising results, with drops in systolic pressure of greater than 30 millimeters of mercury systolic (trials of new drugs to lower blood pressure celebrate an average drop of 5 millimeters). There is some risk of dissection of the renal artery by the intravascular catheter, and residual scars from the burns could potentially result in late stenosis or aneurysms. Though the UHN team is using very strict criteria for its study, there is a very large population of potential patients who might benefit from the technique if it becomes practicable for less severe hypertension. In the future, the technique may be appropriate for patients with mild hypertension, chronic renal failure, diabetes, and medication intolerance. Our goal is to perform the procedure in 25-50 patients per year."

"The team started with a maximalist approach, carrying out the procedures in the operating room with intubation and general anesthesia. We are now stripping the technique down to working in the angio suite and then observing the patients on the vascular ward, rather than taking them to the ICU. It is conceivable that one day soon, this could become an outpatient procedure. The patients undergo an aortogram first, then the catheter is introduced percutaneously and guided into the renal artery. Four burns of two minutes each are carried out in both renal arteries. Each non-reusable catheter costs $6,000."

"The European studies show that the blood pressure drop is generally gradual over a three month period, but there have been patients with dramatic drops overnight. One of the problems in the early surgical denervation experience in the 1950s was that patients developed intractable hypotension. Patients who might choose to undergo denervation would be those noncompliant with medications, those who cannot tolerate medications and potentially patients with renal failure, diabetes etc."

Following undergraduate training at McMaster University, George Oreopoulos completed medical school, surgery residency and a vascular residency at the University of Toronto. He subsequently completed an interventional radiology fellowship at UHN and Mount Sinai Hospital. He is married to Amrit, who is a nephrologist at St. Joseph's Hospital. They have two sons - Dimitrios, 8, and Constantine, 4, who have been overheard saying: "No, there are no beds there, we'll have to try another hospital", when they were playing 'rescue squad'. George has recently resumed the study of martial arts, in which he was a black belt in an earlier version of his career. "Like surgery, the martial arts focus on attention, intention and commitment, emphasizing the right steps with full attention at the right time and in the right way. They also emphasize tempo."

George likes to work with trainees and though he was an outstanding surgeon scientist in Ori Rotstein's lab, he plans to focus on a career as a surgical educator and innovator. He likes the manager role and emphasizes it in his teaching of the residents.



The five –year direct entry vascular residency began this year. It will include training in endovascular procedures. Program Director George Oreopoulos developed his skills in this area during a one-year sabbatical at UHN and Mount Sinai Hospital, “one of the most exciting years of my life”. The angioplasty patients were overtaking the practice of vascular surgery and I was fortunate to have a very collaborative group of interventional radiologists to work with. I was trained in both vascular and non-vascular interventions. The skills required are similar and transferable. It was an eye-opening and challenging experience, but necessary for the long term. Interventional fellows teach me as I teach them. I bring clinical judgment and experience and knowledge of how to get things done in the hospital.”

George takes interventional radiology call and is surprised by the prevalence of calls for interventions for almost everything. “I can spend 11 hours straight performing interventional procedures when I am on call. They are easier to book, shorter and offer the convenience of a stable experienced team. There are interesting problems, lots of innovation and great rounds and great working relations. Because of the collaboration with vascular surgery, the interventional fellows learn to run a vascular clinic, a unique experience for a radiologist. The patients are very rewarding to see following the interventions. They are discharged early, return to the clinic extremely grateful for the improvement that is gained with a minimum of inconvenience and discomfort. The only open cases that we are doing in vascular surgery are those of maximum complexity”.

“The paradigm has shifted and the residency must necessarily shift its focus. Trainees will need cardiac surgery experience to provide them with technical skills. They will need a nephrology rotation, where they will provide access for dialysis. They will need to be on the trauma service, as well as surgical oncology to develop their exposure to open surgery,. Graduates will have become accustomed to using a very expensive angio-operating suite. They may encounter resistance because their skills can threaten other specialists. They may also be resisted by the administration of some hospitals that are unprepared to invest in the equipment required for an angio- OR. The solution to this problem will be regionalized care, rather than vascular interventions in every hospital, using a collaborative model that is not yet prevalent.”

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