Illustration by Eric Dinyer
Hope Chest
By creating the latest techniques, furthering
research and passing this knowledge to residents and students, the Department
of Cardiothoracic Surgery advances the treatment of patients with heart
and chest diseases.
by Lori Baker Schena and Phil Davis
A surgeon settles in front of a video screen and slips his hands into special gloves that control a set of robotic arms in a nearby operating room.
When the surgeon flexes or rotates his hands in the gloves, the robotic arms mimic his movements. Surgery begins, but not with the traditional incision. Instead, the surgeon guides the robot arms through small operating ports between the patient's ribs.
Guided by the surgeon's skilled and steady hands, the delicate robot arms repair a damaged artery.
The patient, spared much of the pain and trauma of traditional coronary artery bypass, goes home in record time-minus the foot-long scar and lengthy recovery that once were necessary evils of a coronary bypass procedure
Welcome to the USC Department of Cardiothoracic Surgery, where innovations like using robots to make already minimally invasive surgery even more minimal may someday become routine.
Robbin G. Cohen, M.D., assistant professor of surgery and vice chair of the Department of Cardiothoracic Surgery, already has performed a coronary bypass on a cadaver using robotic arms and a thoracoscope, an instrument that offers an insider's view of the chest cavity. Cohen anticipates bringing this technology into a clinical setting within a few years.
"Today we use a variety of incisions for coronary bypass operations and different valve procedures-many of which are extremely small," explains Cohen, author of one of the first textbooks on minimally invasive surgical techniques. "Of course, the natural extension of this work is the use of robotic arms, which can enter the chest through smaller ports than can human arms and hands-eliminating entirely the need for an incision."
Innovation was what Vaughn A. Starnes, M.D., Hastings Professor and chair
of the Department of Cardiothoracic Surgery, had in mind when he proposed
the creation of a Department of Cardiothoracic Surgery, a vision that became
a reality in September 1997. Today, the department has ten surgeons and
scientists who maintain patient practices, conduct research, pioneer new
surgical techniques and train the next generation of surgeons. Creating
and running an academic department comes with a host of pressures, but Starnes
thrives on it without sacrificing patient care.
Since 1992, when Starnes arrived at USC to head the then-division of cardiothoracic surgery in the Department of Surgery, cardiothoracic clinical and research efforts have grown more than four-fold. In his first year, USC cardiothoracic surgeons performed 500 procedures. In 1997, they performed more than 2,000
Their research efforts have attracted millions of dollars in grant funding; and their pediatric surgery innovations have captured the attention of surgeons all over the world. An increased demand for USC's cardiothoracic expertise led the department to expand to several facilities in Southern California.
In addition to continued advances in the clinical and research realms, the department is also expanding its teaching role with more residents and more programs for medical students.
"To put it simply, our mission is to further advance the treatment of patients with cardiothoracic diseases," Starnes explains. "We do this on three levels: offering patients the latest clinical techniques; participating in advanced clinical research; and conducting advanced basic research projects."
He adds, "A key part of our mission is to assure that what we learn is passed on through our residents and students."
THE SCIENCE OF HOPE
When a routine-checkup at Childrens Hospital Los Angeles (CHLA) revealed 9-year-old Camden Dir's lungs were working at a capacity of only 22 percent, the little girl was suddenly in desperate need of an immediate lung transplant. Normally, it takes about six months to find a suitable donor-time Camden did not have. Her parents, Steve and Janice Dir, opted for a living-related lobar procedure. In early 1998, the Dir family underwent the operations.
At USC University Hospital, Cohen and Winfield J. Wells, M.D., removed one lobe from each of Camden's parents. The lobes were preserved on ice in a special solution and rushed across town to CHLA, where Starnes transplanted them into Camden's chest. The operation-one of only 25 done on a child over the last five years-went well and doctors are confident that Camden will lead a normal life. "We receive referrals from all over the world for this procedure and have performed transplants in some 75 patients," Starnes says. "We are also being asked to travel internationally to discuss this procedure. It's an exciting innovation, and it came out of our USC program."
Camden's story illustrates the true mission of USC's cardiothoracic surgeons-providing hope through advanced care
"The transplantation program has an excellent survival rate despite the severity of the patients preoperative condition," says Mark L. Barr, M.D., associate professor of cardiothoracic surgery. "This can be directly attributed to the depth of experience of our team members as well as the progress we have made in the areas of immunology and organ preservation research."
One of the main challenges in organ transplantation is the development of new immunosuppressive drugs and techniques to avoid organ rejection. For the past decade, Barr has been the principal investigator for both national and international research studies of new immunosuppressive techniques including the use of photopheresis to address organ rejection in transplant patients.
"Photopheresis is a treatment that combines ultraviolet light and light-activated drugs to increase the immunosuppressive response," explains Barr. "We have found that photopheresis, added to triple drug therapy, results in a significant decrease in cardiac rejection episodes without increasing side effects."
Barr has also been heavily involved in the development of new organ preservation techniques for heart and lung transplantation. Results from his laboratory have impacted clinical practice of cardiac and pulmonary preservation worldwide.
During the past several years, Barr has been involved in the use of mechanical hearts and other heart-assist devices. USC University Hospital is one of the investigative sites of the most modern generation of left ventricular assist devices (LVADs).
"Years ago," Barr says, "researchers attempted to use mechanical hearts to replace the entire heart. But we have found that technically it is a lot easier to keep the heart, and implant a device to assist its function."
The LVAD is usually implanted in the abdomen, with a power supply located outside the body. By keeping the patient's heart, complications are reduced and the possibility of clot formation decreased. Currently, LVADs are used as a bridge to transplantation for patients with end-stage heart disease. Barr, who was recently named a consultant for the Center for Devices in the U.S. Department of Health and Human Services, foresees a time in the not-so-distant future when LVADs will be used as permanent alternatives.
ADVANCING PATIENT CARE
Another intriguing research area is xenotransplantation-modifying animal organs to make them suitable for human transplantation.<
"We recruited a noted basic scientist, Don Kramer, Ph.D., to our CHLA lab to work on this area of research, which continues to be of vital importance in the face of the current organ shortage," says Starnes. "Our goal is to develop suitable animal substitutes that would not be rejected by the human host. The field holds great promise."
Starnes says that the thrust of the basic research program is to concentrate on projects that have the greatest potential to impact patient care throughout the world One project involves vascular restenosis, an overgrowth of muscle in the artery that can lead to clogging or closure of the artery, which occurs after nearly half of all balloon angioplasties and coronary bypasse
"Currently, there is no treatment for this condition," Starnes says.
A USC research team is focusing its efforts in manipulating the genes that determine the surface characteristics of the lining of the blood vessels-especially in response to injury-to prevent them from proliferating and clogging the artery. Funded by a $3 million grant, Starnes, Barr, Frederick L. Hall, Ph.D., director of the USC Cardiothoracic Surgery Research Program, and Erlinda M. Gordon, M.D., are making headway in the search for answers.
The roots of this investigation are in cancer research: Hall brings extensive experience in understanding the pathways in pediatric bone cancer that result in abnormal growth.
"We found that a novel human gene, known as cyclin G1, was over-expressed in bone cancer," Hall observes. "We subsequently discovered that cyclin G1 is also responsible for activating the abnormal proliferation and wound healing in the vascular system, which leads to the closure-or stenosis-of arteries."
Armed with this knowledge, Hall and his colleagues have developed an antisense, or reverse, molecule for the cyclin G1 that blocks the pathway. The antisense molecule inhibits smooth muscle cell growth and proliferation within the vessel wall. This discovery has recently been demonstrated in laboratory models. Other research is underway to develop a system to deliver the gene to the injury site.
"We have developed the payload," Hall says. "Now we have to develop a launch vehicle-a delivery system to get it to our target."
For gene therapy to work, therapeutic genes must get to the right place-the area of injury. "We have developed a series of gene delivery tools-vectors-that target damaged areas where collagen is exposed, as in the cardiovascular system after balloon angioplasty," Hall explains. "These collagen-targeted vectors would deliver therapeutic genes into the smooth muscle cells, which would then prevent or reduce the incidence of vascular restenosis."
If this vector proves successful, the antisense cyclin G1 gene could be injected into a peripheral vein that would then circulate until it locates the area of injury, Starnes says. "In this way, we could deliver a concentrated dose of the gene right where it is needed." Hall predicts that the injectable vector will also play a key role in other aspects of heart disease, with such possible targets as atherosclerotic plaques and areas of ischemia.
IMPROVING OPTIONS
The trachea, also known as the windpipe, has always been particularly frustrating to surgeons. It is mostly composed of cartilage-a tough, flexible connective tissue-that does not get a good supply of blood and heals poorly.
Clark B. Fuller, M.D., assistant professor of cardiothoracic surgery, says homograft reconstruction, taking tissue from another part of the body to reconstruct the trachea, will soon offer improved surgical options to people suffering ailments of the trachea.
Fuller recently performed homograft reconstruction on a 44-year-old woman whose long history of tuberculosis caused narrowing in her trachea. The cartilage used in the repair was taken from her rib cage
Fuller also is using his expertise in video-assisted thoracic surgery (VATS) for procedures normally performed through an incision. VATS evolved from advances in laproscopic surgery in which surgeons use long thin instruments to make surgical repairs without having to make a large incision.
VATS technology is also useful for trauma surgeons to diagnose and treat serious injuries like a traumatic hemothorax.
"Hemothorax, in which blood collects in the space between the chest wall and the lungs, most often occurs from a chest injury," Fuller explains. "The cause of hemothorax is often difficult to determine with a chest X-ray. We have been able to use VATS technology to perform early evaluations to determine the presence and extent of the blood and then treat it. VATS also allows us to examine the diaphragm and the rest of the lungs to see if there are any missed injuries-the Achilles heel of trauma surgeons. It has proved an invaluable procedure in many instances where the cause of bleeding cannot be determined by traditional diagnostic procedures."
SURGEONS IN THE COMMUNITY
While the USC Department of Cardiothoracic Surgery is ivory tower in concept and intellectual fervor, its feet are solidly on the ground.
Surgeons in the program are actively taking the latest research findings into community-based settings. And, community surgeons are finding a home in the program as well. Two examples:
When James G. McPherson III, M.D., M.P.H., worked as an attending cardiothoracic surgeon at New York City's St. Luke's/Roosevelt Hospital Center, he noticed many areas in the city that were underserved by cardiac surgery.
As one of three new assistant professors of cardiothoracic surgery at USC, he does not intend to let that happen in Los Angeles. He is developing heart and bloodless surgery programs at Intercommunity Medical Center and Arcadia Methodist Hospital.
"My goal is to offer first class cardiac surgery services," McPherson says. "The cardiologists at these hospitals will have access to the academic heart surgery programs that we have at USC University Hospital."
While the USC Department of Cardiothoracic Surgery has recruited several academic physicians to work in the community, there is one community physician who took on an academic role. Ever since Ismael N. Nuño, M.D., came to Los Angeles County+USC Medical Center as a boy for emergency surgery to remove a burst appendix, he vowed to return to practice medicine at the hospital.
"While working in the community in the mid-1990s, Dr. Starnes allowed me the opportunity to start teaching cardiac surgery once a week at General Hospital and I just loved it," Nuño says. "It was like coming home. Nothing is as fulfilling as teaching young students as well as treating patients who I could truly relate to from my own childhood experiences. So when I was offered a full-time job as chief of cardiac services at LAC+USC Medical Center, I grabbed it."
For more information about the Department of Cardiothoracic Surgery, or to learn about The Doctors of USC, call 1-800-USC-CARE (1-800-872-2273).