Cath Lab Profile: Continuing a Long History of Innovation at Emory University Hospital | CardioSource WorldNews Interventions
CSWN: Interventions speaks with Habib Samady, MD, director of interventional cardiology at Emory University and the cardiac catheterization lab at Emory University Hospital, and Syed Tanveer Rab, MD, interventional cardiologist at Emory University Hospital, member of the ACC's Interventional Section Leadership Council and Councillor of the ACC's Georgia Chapter.
The team at the Emory University Hospital cath lab
Since the beginning of interventional cardiology, Emory University has been home to some of the earliest leaders in the field. Could you describe some of that history?
Habib Samady, MD: We think of Emory University as the birthplace of coronary angioplasty and interventional cardiology. In 1980, we were incredibly fortunate to recruit Andreas Gruentzig, MD, who pioneered angioplasty while working in Zurich. In those seminal years between 1980 and 1985, Emory University was basically where everybody came to learn how to perform coronary angioplasty. Over the years, we have trained dozens and dozens of interventional cardiologists from around the world. We are very proud of that tradition.
One of the people who recruited Dr. Gruentzig was Spencer B. King, III, MD, another pioneer of interventional cardiology who led the Emory interventional program after Dr. Gruentzig's death. Dr. King led early stent development work, vascular brachytherapy research, as well as the National Institute of Health–funded EAST trial that compared multivessel angioplasty to bypass surgery. Dr. King was succeeded by John Douglas, Jr., MD, who was the first interventional cardiologist in the United States to place a coronary stent.
In 2011, I had the privilege of taking over for Dr. Douglas as the program's director. Our areas of expertise now are intracoronary imaging and physiology, translational research in atherosclerosis science in the cath labs, and coronary biomechanics. We are the biomechanical core laboratory for the ABSORB III Imaging Substudy and are running the SHEAR STENT multi-center, multinational trial, among other studies.
In addition, like many centers around the country, we are very interested in percutaneous coronary interventions (PCIs) for chronic total occlusions (CTOs). These techniques are somewhat different than those for performing a normal PCI, so we have a pretty active CTO program here as well.
The Emory interventional cardiology program has really expanded, so that we now help direct six organizations, including the four Emory hospitals:
- Emory University Hospital, our main flagship hospital
- Emory University Midtown (Cath Lab Director: Henry Liberman, MD)
- Emory St. Joseph's Hospital (Cath Lab Director: William Lieppe, MD)
- Emory Johns Creek (Cath Lab Director: Gregory Robertson, MD)
Then there are two other hospitals where we perform coronary angioplasty and other procedures:
- the Atlanta VA Medical Center (Cath Lab Director: Kreton Mavromatis, MD)
- Grady Hospital, a large inner-city hospital (Cath Lab Director: Michael McDaniel, MD)
Overall, our system has a pretty large footprint in this area.
Emory is a leader in performing TAVR in the interventional suite. Can you describe the process of implementing this program at your lab?
Dr. Samady: Our structural heart disease and TAVR programs are areas where we embrace a collaborative, shared decision-making approach. Vasilis Babaliaros, MD (interventional cardiology), and Vinod Thourani, MD (surgery), are co-directors of the Structural Heart and Valve Center at Emory. Their leadership has propelled Emory into one of the top three structural heart disease and TAVR programs in the country in terms of volume.
When we started the TAVR program, we performed them mostly in the hybrid operating room. We realized, though, that Medicare reimbursement for TAVR is limited and the valve is very expensive. The hospital actually ended up losing money on some of the TAVRs that were done in the operating room with anesthesiology and used other intense resources.
So, Dr. Babaliaros and his team basically posed the question, "How are we supposed to gain the experience and the confidence to bring TAVR to the cath lab so it can be performed safely without intense resource utilization?" To make the procedure safe, our cath lab nurses became very experienced in the delivery of heavier sedation under the guidance of the cardiologists.
Another resource-intense part of the care of TAVR patients was the typical admittance to the coronary intensive care unit afterwards. Our solution was to "pre-close" the femoral access site so patients could just transfer to the step-down unit and be discharged in a couple of days.
Syed Tanveer Rab, MD: Emory, I believe, is now a "go-to place" for TAVR and adult congenital heart disease. With support from Emory University, philanthropic grants, and research grants a structural heart center was established, and a dedicated staff was chosen, including team leaders who provided one-on-one instruction and teaching for the staff member or the interventional fellow. In 2007, we also implemented a "Heart Team" approach, which included inverventional cardiologists, cardiac surgeons, research staff, a dedicated cardiac sonographer, and a board-certified echocardiographer.
A database of TAVR cases was also established; this database is extensive, with each patient having an individual profile with their imaging results. For research and training purposes, we can also generate a PowerPoint presentation for each case to share with other colleagues and in national meetings. Emory was also a prime site for the PARTNER trial, and to date more than 800 TAVR procedures have been performed here. Besides TAVR, our structural heart center is also equipped to treat other valvulopathies, including perivalvular leaks, implanting the MitraClip for severe mitral regurgitation, and the Melody transcatheter pulmonary valve for conduit graft stenosis in adult congenital heart disease.
Through a partnership with the pediatric cardiologists at Sibley Heart Center of Children's Healthcare of Atlanta, our structuralists are also dual-credentialed in pediatric cardiology. In addition, new investigational devices are being developed in collaboration with Georgia Tech, so with these partnerships, I would say our interventional program for adult congenital heart disease is really thriving.
How do you handle staff communication and training—in particular, with TAVR and imaging? Is there a learning curve or any special training considerations with this approach?
Dr. Samady: We are very lucky that Dr. Babaliaros was able to receive training directly from Alain Cribier, MD, who was the first person in the world to perform TAVR. After training, Dr. Babaliaros returned to Emory and really ramped up experience levels very quickly.
When we moved TAVR into the cath lab, I would say that there was a change in the threshold in our experience because there is a safety net in the operating room. If something happens in the operating room, the surgical option is immediately available. So, your confidence level, your abilities, and your experience with the TAVR procedure must be very high before you perform it the cath lab.
That's where the learning curve really starts to pick up, not only in terms of femoral access and vascular complications, but also in terms of placing and sizing the percutaneous valves. Dr. Babaliaros has led the effort in sizing TAVR that includes performing computed tomography and inflating a balloon in the valve before TAVR. Based on the resistance of the balloon in the valve, you can help size it. We also have a very active peripheral arterial disease program, which is directed by Khusrow Niazi, MD, and where Dr. Niazi and other peripheral interventionalists conduct numerous clinical studies, in areas such as peripheral drug-eluting balloon therapies and carotid stents.
Dr. Rab: When fellows or attendings enter the TAVR program, they receive on the job training for 6 months to a year. The learning curve is between 50 and 100 cases, and it also helps that we have large-volume sites in the Emory system. During training, staff communication occurs on a one-to-one basis, with competencies evaluated on a monthly basis. Newly-graduated nurses and techs also attend training courses and seminars.
This was also the case for adopting radial access for catheterization. Although there was an initial reluctance, the majority of cases are accessed through the radial artery. Emory has had the program for 12 years, so now even some of the more veteran interventionalists are using the radial approach. Many of the patients who undergo these types of procedures or an uncomplicated intervention are then eligible for same-day discharge.
What measures do you have in place to ensure quality of outcomes?
Dr. Rab: I think quality metrics are very important at Emory—our academic facility was recognized with Accreditation for Cardiovascular Excellence, and Emory University Hospital was ranked #2 among the more than 100 academic centers participating in the national University Health Consortium Quality Leadership Awards. I would attribute these achievements to good communication and attention to quality metrics.
There is a weekly meeting in all specialties—whether it is infectious disease or critical care or cardiology—where each case is discussed as we look for areas to improve. There are many team members who are present at these weekly quality control meetings; STEMI program meetings, for instance, include a quality assurance cardiologist, an interventionalist, cath lab nurses, the cath lab STEMI coordinator, the emergency department physician, and the emergency department charge nurse. The discussion includes a review of echocardiograms and angiograms, as well as delays in any part of the process that we can improve on. If there is a metric that is not followed, we make sure to follow through and provide feedback to the relevant staff. The data we collect is used for tracking core measures performance, for reporting to the ACC's National Cardiovascular Data Registries®, and, ultimately, to help us improve our processes.
In terms of improving outcomes for STEMI patients, we also have a successful door-to-balloon (D2B) program and were given a Bronze Recognition award from the American Heart Association's Mission: Lifeline program. Our program is unique for a large metro area: the interventionalist picks up a patient from the emergency department, and along with the staff there, preps the patients for the cath lab before the full on-call cath team arrives to start the procedure. At the 2010 ACC meeting we reported 30-minute reductions in D2B times using this program, and now, we have a nearly 100% success rate in achieving D2B times under 90 minutes. We, along with several other leaders in the area, also developed a STEMI manual for the AHA Mission: Lifeline program.
What are some other clinical questions that the team at Emory University Hospital is trying to answer?
Dr. Samady: The sort of "holy grail" that interventional cardiologists have always been searching for is a way to determine which part of a coronary artery is likely to suddenly occlude due to plaque rupture or erosion and cause a cardiac event— even in a patient with nonobstructive coronary disease or who has been evaluated and is compliant. Despite advances, this is still a problem in 2014. We are not good at figuring out which segment of the coronary artery with some narrowing due to cholesterol plaque will suddenly shift to a closure. Unfortunately, about half of those patients die before ambulances can reach them.
We are working to reduce that number. Based on the research we are doing here, we believe a combination of anatomic imaging (like optimal coherence tomography or intravascular ultrasound) with what we call biologic imaging (or shear stress, which basically refers to the frictional force of blood as it travels through the coronary arteries) will help identify vulnerable coronary segments that could potentially be treated preemptively.
To help answer this question, we are looking at the vessels, microvascular function, and endothelial function of patients with nonobstructive coronary disease. We repeat evaluation (consisting of intravascular ultrasound, optical coherence tomography, and wall shear stress analysis) over time to try to predict which of these variables can identify plaque progression and vulnerability. We're finding that wall shear stress is actually a pretty strong predictor, and we're aiming to translate that finding into larger clinical trials.
Another clinical area we are very passionate about is women and heart disease. Many women have under-diagnosed coronary disease. We have a large referral base of women who may have bounced around to multiple cardiologists and cath labs, had a coronary angiogram, and were told, "Your angiogram is normal, you don't have any problems with your heart."
However, we understand that even when the angiogram is normal, you can have problems with your microvasculature or endothelial function, which we can test for here. Unfortunately, many of these women have just been shifted around with all these chest pain syndromes for years. But by looking at their vessels or microvasculature, we can determine that they actually are not fine—they may have zero endothelial function or coronary vasospasms or other factors that are causing the trouble. One of our active trials in this area is the MARINA study, which randomizes patients with microvascular disease to the antianginal medication ranolazine or placebo.
Our cardiologists and nurse practitioners staff the women's program, and we also will refer patients to gastroenterology, to psychiatry, or to obstetrics and gynecology. Clearly, we understand that not all women with chronic chest pain syndrome have a problem with their microvasculature. Perhaps they have GI problems or other issues, so a multidisciplinary approach is critical to determining the problem.
Dr. Rab mentioned the collaboration with Georgia Tech—can you explain some of the aims and clinical goals of that partnership?
Dr. Samady: All of the work we do—whether it's with wall shear stress or biomechanics—is done in cooperation with colleagues at Georgia Tech, including Don Giddens, PhD, former dean of the College of Engineering there, and Alessandro Veneziani, PhD, here at Emory's Mathematics Department. This partnership offers a unique combination of interventional cardiologists and imagers on our side and bio-mathematicians and engineers from Georgia Tech and Emory Mathematics.
Together we attempt to answer some of those clinical questions we discussed earlier, including stent biomechanics and the way stents heal. This is an important area of study because if you deploy two different types of stents—perhaps a rigid metallic stent and a compliant bioresorbable platform—we know that the way they heal in the coronary arteries is completely different. By studying the biomechanics of these stents, we are hoping to reach an understanding of where certain stents may perform better.
As new stent platforms are introduced, particularly some of these bioabsorbable and compliant stent technologies, the regulatory agencies are extremely interested in understanding how stents heal with regard to their biomechanics. It is one thing to test these technologies at the bench in vitro, but it's more realistic to actually test their performance in diseased and calcified human coronary arteries.
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