Faculty Spotlight: Tobias Deuse, MD
In recent years, many new avenues have emerged for treating cardiac valve disease. Conditions such as mitral valve prolapse can be treated through open-heart surgery, minimally invasive surgery, or sometimes without any surgery at all – instead inserting collapsible valves or clips through a small incision in the groin and placing them in the heart with catheters.
"Nowadays, when we have so many options, it’s absolutely crucial that patients are seen by both a cardiologist and a heart surgeon who work together to determine the best treatment option for each patient," said Dr. Tobias Deuse, an adult cardiothoracic surgeon who recently joined the UCSF faculty and is the director of the minimally invasive cardiac surgery program. "There are some procedures that cardiologists do, some that surgeons do, and some procedures that we do together because they involve both of our areas of expertise. With modern heart interventions, the line between cardiology and surgery has become less obvious."
Dr. Deuse was recruited from the University of Hamburg-Eppendorf, one of the leading mitral valve centers in Germany. He is excited by UCSF’s team approach to complex heart disease, and recently led the establishment at UCSF of a combined clinic where patients see both an interventional cardiologist and cardiac surgeon on the same day; the specialists then consult with each other and tailor a treatment plan for each patient’s unique situation.
"If patients meet with a doctor who tells them one thing, and then the next doctor tells them something completely different, they go home confused and frustrated – it’s terrible!" said Dr. Deuse. "But when they see different specialists working together to develop an individualized plan for them, they feel much better. The hospitals that adapt this team approach will likely be most successful."
"Dr. Deuse has had excellent training and is a very gifted surgeon," said Dr. Scot Merrick, chief of the Division of Adult Cardiothoracic Surgery and the Helen and Charles Schwab Distinguished Professor in Surgery. "He is also a very outgoing person, and is easy to get along with. That [combination] is hard to find in cardiac surgery circles. His interest in new technologies is going to be great. He has used a lot more devices in Germany than we have available here in the US, so he has a lot of experience with them and will bring a lot of new ideas."
Keeping His Day Job – And Night Job
Dr. Deuse studied physics as an undergraduate at the University of Stuttgart in Germany, then earned his medical degree from Ludwig Maximilian University in Munich, where he also completed his cardiac surgery internship before completing his cardiovascular surgery residency at the University Heart Center in Hamburg-Eppendorf, Germany.
He was drawn very early to cardiothoracic surgery, in part because of a fascination with cardiac anatomy and the challenge of performing meticulous surgery that required tiny sutures. Even as a medical student, he started doing heart transplants on rats. It was there, 19 years ago, that he met Dr. Sonja Schrepfer, another medical student who became his lifelong research partner and eventually his wife. "It was very romantic, meeting in the basement in the animal OR!" said Dr. Deuse with a laugh.
Dr. Deuse later completed a cardiothoracic surgery transplant fellowship at Stanford University, a pioneering center in the areas of heart and heart-lung transplantation. Among his mentors were Dr. Bruce Reitz, Dr. Philip Oyer and Dr. Craig Miller. Dr. Deuse was then recruited back to Germany, where he served as director of the heart and lung transplantation program at the University of Hamburg-Eppendorf and also practiced as a general cardiac surgeon.
Throughout his career, Dr. Deuse likes to joke that he has had two jobs. His day job is performing elective cardiac surgery. His night and weekend job is performing heart, lung and heart-lung transplants, during the off hours when operating rooms are available for these unscheduled, life-changing procedures.
Dr. Deuse has always juggled a third job, too – in partnership with Dr. Schrepfer, now a renowned stem cell scientist and immunobiologist, he has conducted vascular biology research with the goal of finding better ways to prevent cardiovascular disease.
Complex Mitral Valve Repair
In Hamburg, Dr. Deuse’s "day job" included performing hundreds of heart surgeries, with a focus on reconstructive valve surgery. Perhaps three-quarters of these procedures are complex mitral valve repairs – fixing problems of the valve between the left atrium and left ventricle. "Mitral valve repair is really interesting, because it’s demanding, and no two valves are exactly the same," said Dr. Deuse. "For each one, you have to come up with a strategy, which may be very different from the last case you did."
The mitral valve is a parachute-like structure, with two leaflets that open and close a bit like a pair of French doors, and which are connected to the inside of the heart by a number of chords. When the leaflets fail to close together tightly, blood in the left ventricle can flow backwards to the left atrium, compromising blood flow to the rest of the body. Dr. Deuse comes up with a tailored solution for each valve he repairs. For example, if part of a leaflet is calcified and doesn’t bend properly, Dr. Deuse can modify the other leaflet so together they form a tight seal. If the chords which pull the leaflets open and close are ruptured, he can insert artificial Gore-Tex chords to replace them.
"There is a lot you can do to fix valves, which is why most of them can be repaired," said Dr. Deuse. Repair of a patient’s own valve is preferable to replacement, since bioprosthetic valves – such as those from pigs or cows – degenerate over time, and patients younger than 65 may eventually need a second valve replacement. Mechanical valves, which are made from metal and carbon, can last longer, but require patients to take a blood thinner to prevent clotting around the valve. "A nicely repaired valve can last a lifetime," said Dr. Deuse, noting that for cases where repair is not possible, he and his team can also replace the valve.
Minimally Invasive Approaches
For valve surgery, Dr. Deuse specializes in minimally invasive approaches. Whereas traditional open surgery usually involves a long incision through the center of the chest, which cuts through the breastbone and requires several weeks to heal, he has significant experience in using smaller incisions. Through these "keyhole" incisions, he inserts long-handled surgical instruments and three-dimensional endoscopes, which allow him to view the surgical site on a video screen as he performs the procedure. These incisions can be made in between the ribs, so no bones need to be cut. "If we can avoid opening up the sternum, patients maintain a fully functioning and stable chest," said Dr. Deuse. "That allows patients – especially those who are frail and elderly – to rehabilitate and mobilize more quickly."
For example, patients recovering from open cardiac procedures should avoid lifting suitcases and other heavier items or using their arms to help them walk for eight weeks, due to the risk of reopening their surgical incision and thereby increasing the chances of wound infection. By contrast, patients who have minimally invasive surgery are allowed to move freely and use their arms as soon as they feel up to it.
Contrary to conventional wisdom, minimally invasive surgery is feasible even in overweight patients. "It’s absolutely true that it’s much harder to do in obese patients," said Dr. Deuse, noting that surgical instruments need to be inserted through a deeper incision to get to such patients’ hearts, and there is less room to maneuver because the internal organs push the patient’s diaphragm higher into the chest cavity. "But very obese patients benefit very much from this approach, because they’re at even higher risk of wound infections and have more difficulty standing up and moving after the procedure due to their weight. Because it can benefit such patients, it’s worth the effort."
Dr. Deuse has given workshops for minimally invasive mitral valve repair, where he trained other heart surgeons on the procedure. Usually in two-day events, the participants learned about the theory behind valve repair and could then watch live cases in the OR.
Innovations in Heart Transplantation and Assist Devices
Before joining the UCSF faculty this year, Dr. Deuse directed the heart and lung transplantation program at the University Heart Center Hamburg, and developed expertise with new technologies and devices. For example, because donor hearts are unable to tolerate prolonged periods of time without blood supply, they are usually stored on ice during transit and should be implanted within four hours after retrieval from the donor. To improve preservation of the heart and enable transportation of donor organs over longer distances, a new technology called ex vivo heart perfusion (nicknamed "heart in a box") has been developed. This portable box connects the donor heart with a temporary blood supply, allowing the heart to keep beating and receiving oxygen as it travels to its destination.
This technology was recently tested in several countries, and Dr. Deuse’s program was among the largest enrollers for the German national trial. "The technology is reliable and not only improves organ preservation, but also allows a functional assessment of the heart while it is connected to the device," said Dr. Deuse. "However, the high costs and laborious operation of the device so far preclude a widespread use of this technology." The device is commercially available in Europe, but is still under clinical investigation in the US.
Because of the scarcity of donor hearts, only a fraction of patients with end-stage heart failure will receive a heart transplant. One alternative or "bridge to transplant" procedure is the implantation of a ventricular assist device (VAD), a miniaturized pump that can help patients whose own hearts are unable to keep up with the body’s need for oxygenated blood. "Just a few years ago, we had these big pneumatic devices which were large, heavy and noisy," said Dr. Deuse. "But modern VADs are becoming a better and better option for heart failure patients."
The latest generation of VADs are smaller than ever before, feature continuous flow pumps rather than the bulkier pulsatile pumps, and can be a good option when patients might otherwise die waiting for a donor heart. Because of his experience with keyhole cardiac surgery, Dr. Deuse established minimally invasive techniques for VAD implantation as well. At UCSF, he joins Dr. Georg Wieselthaler, an internationally renowned expert in the development and implantation of VADs as well as in heart transplantation.
Preventing Heart Attacks
Dr. Deuse is also passionate about the research he conducts with Dr. Schrepfer, which currently focuses on new strategies to prevent restenosis of coronary arteries. This occurs when the blood vessels feeding the heart re-narrow after an intervention such as an angioplasty, which uses inflatable balloons and stents to push plaque against the artery walls to restore blood flow.
Scientists now believe this process is not so much like a gradually clogging sewer pipe, but happens because of inflammation in the artery wall. Specifically, the smooth muscle cells –which are the main cell population of the arterial wall – proliferate and become resistant to obeying signals to commit suicide when required for the body to maintain overall health.
"We looked at the growth characteristics of these hard-to-control proliferative cells, and found so many similarities to cancer growth," said Dr. Deuse. In particular, they identified a "switch" that seems to trigger the transformation of normal cells into out-of-control cells that are implicated in restenosis. Drs. Deuse and Schrepfer have begun a clinical trial in Germany with angioplasty patients to test a new class of restenosis inhibitors; these borrow a page from the cancer medication playbook in their method of taming uncontrolled growth.
"So far, we couldn’t find any major side effects or disadvantages of this treatment," said Dr. Deuse. "If we can apply even more localized approaches – such as using these inhibitors as a stent coating – I think this will make any side effects even more unlikely."
Dr. Deuse counts himself lucky to collaborate with a full-time lab scientist. "Since we met in medical school 19 years ago, Dr. Schrepfer and I have done all our research together," he said. "It makes it a little easier for me to come to the lab whenever I have time, because she fills in the gaps when I am not around."
Dr. Deuse is also an enthusiastic educator, and has been inspired by his own mentors, such as Dr. Reitz at Stanford. "You learn the technique when you work with him, but you get so much of the spirit that’s behind this, and it’s contagious," said Dr. Deuse. "When I teach, I try to make the residents or fellows dig deep and understand the basic principles of the disease, and the strategy behind what we are doing. It’s more than just sewing parts together. It’s asking, ‘Why are we doing it this way, and not another way?’ It’s almost like learning a language – rather than learning words by rote, helping them understand where the words come from, and what are their roots."
He and Dr. Schrepfer are excited to join the UCSF faculty. "The research institutions here are phenomenal," he said. "The combination of excellence in clinical care, cutting-edge basic science, and the many bright people clustered here at UCSF is just incredible. It doesn’t get any better than this."
When he is not working at his day, night or weekend jobs, Dr. Deuse enjoys running, cycling and cheering on the Golden State Warriors.
– Elizabeth Chur