A Long-Term, Multidisciplinary Physician Collaboration Flourishes in Hybrid Labs

Dr. David Brown, an interventional cardiologist, Dr. Todd Dewey, a cardiothoracic surgeon, and colleagues work closely together on hybrid procedures, particularly aortic valve replacement. Dr. Brown and Dr. Dewey share their thoughts on building and working in hybrid labs, and what they have learned from their participation in transcatheter aortic valve implant trials, most recently the PARTNER (Placement of AoRTic TraNscathetER Valve) trial. Can you describe the hybrid labs at The Heart Hospital and Medical City Dallas Hospital? Dr. Dewey: We have had two Siemens hybrid rooms at The Heart Hospital for almost two years. We do a fair amount of thoracic endografting, abdominal aortic endografting, and aneurysmal disease. We are using The Heart Hospital hybrid rooms for lead placements and pacemakers, and defibrillator placements. At Medical City Dallas, which has two Philips hybrid labs, there is quite a large structural heart program and there we are doing transcatheter aortic valve replacements. Our aortic surgery volumes have tripled over the past three years. Typically, we schedule our hybrid procedures as surgical cases. We try to do these procedures as the first case of the day, with a 7:30am start time. The interventional cardiologist may come to the hybrid room and put stents in either old bypass grafts or native vessels. The surgeon then performs a minimally invasive valve surgery. This collaboration means we do not have to extend the time or complexity of the operation to dissect the heart out from surrounding adhesions and do bypass grafts, particularly if a lesion appears suitable for a good result with a stent. Everything is done simultaneously in the same room to shorten the time and complexity of the procedure. Dr. Brown: Our work together started with the development of abdominal aortic aneurysm (AAA) stent grafting and subsequently, carotid stenting, which is performed by cardiologists, vascular surgeons, and cardiac surgeons. This collaboration has increased with the transcatheter valve trials, due to the severity and complexity of elderly patients with critical aortic stenosis. The transcatheter valve procedures have required the closest collaboration we’ve ever had. We started doing them in the operating room with a mobile C-arm, and quickly found that mobile imaging was a serious deficit. We truly were wondering what we were looking at. We couldn’t see valvular calcium or the actual stent valve. We had a case where the valve embolized while using the mobile C-arm, and that’s when we knew the significance of high-resolution fixed imaging. It led us to develop our hybrid operating rooms for better imaging and patient safety. In the interim, we made the cath lab into a pseudo OR and a poor man’s version of a hybrid room, with much better imaging, but a compromise on space, since our cath labs were 560 square feet. We knew we needed hybrid operating rooms. The PARTNER trial really led us to getting hybrid OR labs, and we now have hybrid rooms in both The Heart Hospital and Medical City Dallas. These rooms are highly utilized by multiple specialties, have the excellent imaging interventionalists require, and are key to having all the tools and instruments the surgeons want in the room. It’s a comfort zone for everyone. Dr. Dewey: We use the hybrid room 24 hours a day, with an on-call team for both the cath lab and the operating room. For many of the thoracic and abdominal aortic procedures, we often just use the operating team. The OR crew has spent the last several years collaborating with the cath lab personnel. The OR team is trained in most catheter-based procedures, except for coronary interventions, and that’s when we call in the cath lab team to help the cardiologists. For all the thoracic and abdominal endografting, however, our OR staff is comfortable with the imaging equipment, and the use of most catheters and wires. Were you both involved in the creation of the hybrid labs at the two hospitals? Dr. Dewey: Yes, Dr. Brown and I were involved. There was a committee formed by the hospital that included a number of key stakeholders, generally people who would be using the labs. Along with other vascular surgeons, I was on that committee. We looked at vendors and technology, and what we wanted to put in the rooms. What are some of the more common procedures done in the hybrid rooms? Dr. Dewey: Probably the best revascularization procedure we do is the LIMA-LAD (left internal mammary artery-left anterior descending coronary artery) graft. Outcomes with this graft are superior to stenting or coronary artery bypass graft surgery (CABG) using saphenous veins. Vein graft patency is somewhere around 80-85% at one year. Thus, in certain situations, bypass grafting using veins as the conduit is not as good as some of the results seen with drug-eluting stents. We apply the best technology in order to get the best result for the patient. If there is a lesion in a vessel where it looks better to intervene percutaneously, then that’s what we do. If we can place a stent in a circumflex or other artery, and all the patient needs is a LIMA to the LAD, then we can then use a small access incision and perform a minimally invasive direct coronary artery bypass (MIDCAB) procedure. It saves the patient from a larger operation. The last few years have also seen quite a shift in therapy for aneurysmal disease, particularly abdominal aneurysmal disease. Ten years ago, our standard practice was to do an open procedure on everybody. The hospital length of stay was 10 to 12 days and the total recovery time was generally measured in months. Patients did well once they recovered, but there was certainly more risk and a greater chance of complications. Today, for most of these cases, if patients have anatomy suitable for the technology, we perform an endograft in the hybrid operating room. There are two companies that make devices for peripheral endografting: Medtronic and Gore. We use both products in AAA procedures. Sometimes we do them percutaneously and on other occasions, depending on the anatomy, we will actually cut down the femoral vessels. We can cover the entire abdominal aorta and iliacs from the inside, using this approach. Patients are generally home within 48 hours and recovery time is usually a few weeks. It’s certainly a significant improvement, which has developed not only for abdominal aneurysms, but also for thoracic aneurysms. The next advance will be branch grafting, which is creating devices that are not just simple tubes, but also contain side branches, so that you can get into side vessels such as the subclavian arteries, renal arteries or some of the abdominal arteries. It will allow coverage of larger portions of the thoracic and abdominal aortas without obstructing an important branch. How are patients managed once it’s been decided that they would be good candidates for a hybrid lab procedure? Dr. Dewey: The most common procedures that surgeons and interventionalists do together involve structural heart problems, such as aortic stenosis. We have a combined valve clinic that meets every Tuesday afternoon. Dr. Brown, along with one of his partners, Dr. Bowers, is there, and I and one of my partners, Dr. Mike Mack, also staff the clinic. We see the patients jointly and make decisions concerning patient management as a team, including whether balloon aortic valvuloplasty, conventional valve surgery, or a transcatheter valve implantation is the best treatment option. As high-volume operators, can you share some of your learning process with aortic valve replacement? Dr. Dewey: We have certainly learned a number of things over the years. I think Dr. Brown really hit on the main point that imaging is the key to the procedure. If you can’t see accurately what you are doing, it’s hard to be successful with transcatheter valve implantation. Both Dr. Brown and I have been involved in transcatheter aortic valve procedures since 2004. It’s been quite a learning experience, starting with procedures that took 4 or 5 hours to perform, to procedures that now are generally completed in 45 minutes. The sponsor of the PARTNER trial, Edwards Lifesciences, makes sure that all investigators are well trained, and have adequate proctoring and support when initiating their program. The goal is not to recreate the mistakes that others have made, but to learn from them and avoid them. When we first started, we were trying to develop a new procedure along with several other sites in the world, essentially from scratch. Early on, we made nearly as many mistakes as we did things right. Dr. Brown: Dr. Dewey is the leading surgeon in the country for transapical aortic valve implantation, and one of the top surgeons in the world in the volume of cases he has done. Our site was third in the country with the number of patients enrolled in the PARTNER trial. It is a big part of what we do every day. Today, we are going to see 15 patients sent from across the southern U.S. to see who may be eligible for the transcatheter aortic valve implant trial. Dr. Dewey, at how many locations have you proctored? Dr. Dewey: I’ve had the pleasure of proctoring sites on 3 continents: Europe, the United States and Australia. I always bring something away from those experiences. I teach operators to do the procedure the way we do it, but I also learn from them, too. Everyone involved in doing these procedures is a top-notch, high-volume cardiologist or surgeon, so there is always something to learn. You have both emphasized the importance of imaging. What is happening with the development of imaging technology? Dr. Dewey: It’s all about visualization, particularly with the transcatheter valve. There’s quite a bit of innovation in the technology being brought to market. In 2007, transcatheter technology received CE mark approval in Europe. Since, a number of companies have been investing in new ways to image the aortic annulus. Philips is working on their Heart Navigator project, which is a software package that allows a patient’s preoperative CT scan to be loaded onto the system. It recreates a near-3D image of the area of interest on the fluoro screen. We think it is intriguing technology. Not only could it be very useful in terms of finding the appropriate imaging angle for transcatheter valve deployment, but it also has applicability for abdominal and thoracic endografting. We’re just beginning to look at this technology. Dr. Brown: As more minimally invasive and transcatheter mitral valve work invades the current aortic valve imaging arena, the same technology will develop over the next 5 years — a superimposition of CT scan and fluoroscopy, allowing us to map anatomy, physiology, and measurements for the mitral valve. I think this is a burgeoning field. We will be able to drop in everything from sutures to anchors, rings and valves, with a very elegant roadmap system that will tie CT, echo, 3D echo, and perhaps additional modalities, together. Where is clinical trial research heading? Dr. Brown: In coronary disease, we have gone through the SYNTAX and FREEDOM trials of multivessel disease, comparing complex multiple stent implantation with CABG. An upcoming trial, the EXCEL trial, is going to look further at this area, to include hybrid procedures with minimally invasive bypasses simultaneously with stenting, which is another ideal use of the hybrid room. Other aortic valves moving through clinical trials are CoreValve, Ventor, Symetis and Direct Flow. At the same time, there is significant transcatheter development going on for mitral valves. There is an ever-building pressure in the mitral valve field, where everybody’s been trying to do the same thing for close to 10 years. In the past 5 years, there hasn’t been a great deal of clinical change. But, I think we are about to see the top come off the pressure cooker and all sorts of things evolve or erupt, if you will, ranging from minimally invasive mitral valve replacement to transthoracic repair, as well as all kinds of minimally invasive treatments and percutaneous approaches. Mitral valve repair is a growth area for clinical evaluation trials, and research that will focus on the use of the hybrid room between the cardiac surgeons, cardiologists and the abilities of those teams. Any final thoughts? Dr. Dewey: I would emphasize that going forward, the practice of cardiovascular surgery, in particular, is increasingly geared towards collaboration between surgeons and cardiologists. If you look at the specialties, they are continuing to merge towards each other. I think there will be more and more opportunities for surgeons and cardiologists to work in collaboration. Dr. Brown can be contacted at davidbro@baylorhealth.edu Dr. Dewey can be contacted at tdewey@csant.com

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