Aortic Aneurysm Surgery
Some of us may not consider numbers to be our area of expertise, but when we’re talking about matters of life and death, numbers can suddenly become very important.
Here are a few to consider.
An aortic aneurysm is a bulge in the aorta, the largest blood vessel in the body. Aneurysms can form in the chest or abdomen (or both). Sixty percent of aortic aneurysms involve the part of the aorta that extends immediately from the heart. Forty percent occur in the segment extending into the abdomen. The larger the aneurysm grows, the greater the chance it may dissect or rupture, which is life-threatening.
Abdominal aortic aneurysms (AAA), or aneurysms in the abdominal part of the aorta, are the 13th leading cause of death in the United States and the 10th leading cause of death in men.
NewYork-Presbyterian’s aortic surgeons had a 100% success rate (data from 2013-2014) in treating abdominal aneurysms involving the arteries of the kidneys (infrarenal aneurysms).
This success has become possible through the creation of a comprehensive Aortic Center at NewYork-Presbyterian/Columbia University Medical Center. This integrated program, directed jointly by cardiac and vascular surgeons in the Department of Surgery, features a 24/7 on-call team of cardiologists, vascular surgeons, cardiac surgeons, and interventionalists who specialize in the treatment of aortic aneurysms and dissections. This team is carefully coordinated by Tracy Andrews, DNP, ACNP, a highly experienced cardiac surgical nurse practitioner, who rapidly assesses incoming patients, obtains critical test results, and directs patients to the appropriate specialists for treatment.
This unusual collaboration provides expert care for patients with all types of aneurysms and dissections, and is particularly important in the case of aneurysms and/or dissections that require both cardiac and vascular expertise.
Prior to the development of the Aortic Center at NYP/Columbia, aneurysms were treated by different specialists depending on whether they were located above or below the diaphragm, explains Dr. Richard Green, Director of the Division of Vascular Surgery and Endovascular Interventions. Thoracic aneurysms (those above the diaphragm) were traditionally treated by cardiothoracic surgeons, and those below the diaphragm, in the abdominal cavity, were the purview of vascular surgeons. But experience has taught the team that the best results are achieved when cardiac and vascular surgeons work together to ensure optimal care of the entire aorta.
About aortic aneurysms
Aneurysms are areas in which the aortic walls are weakened, thinned and distended, similar to the way that a balloon bulges outward as it is blown up. Aneurysms may occur in any part of the aorta. If the aneurysm occurs near the heart or above the diaphragm, it is considered a thoracic aortic aneurysm and if it is below the diaphragm in the abdominal cavity, it is considered an abdominal aortic aneurysm. Aneurysms that occur right where the aorta extends from the heart, called aortic root aneurysms, may impair the function of the aortic heart valve and reduce blood flow to the rest of the body. Some aneurysms involve both thoracic and abdominal sections of the aorta.
Smaller aneurysms may be monitored and may not enlarge to the point of requiring surgery, but an aneurysm that enlarges to 5 cm or more is at risk for tearing, or dissection. Dissection is a life-threatening emergency that requires immediate surgery. Ideally, aneurysms are detected and monitored or treated before any symptoms occur; in some cases, aneurysms are detected incidentally during X-rays or CT scans for other conditions.
Treatment of aortic aneurysms
At NewYork-Presbyterian, aneurysms can be successfully repaired with excellent outcomes and with mortality rates well below national rates. For instance, consider the average death rates of patients undergoing minimally invasive repair of abdominal aortic aneurysms. Nationally, an average of 3% of patients undergoing elective surgery die, and during emergency surgery, the rate of death is 13%. At NewYork-Presbyterian, the mortality rate for both elective and emergency surgical patients was 0.0% in 2014.
One of the keys to the successful treatment of aortic aneurysms is careful monitoring and referral for surgical consultation to avoid rupture or dissection of the aneurysm. Another factor in the center’s high success is its surgeons’ expertise in determining which treatment approach is ideal for each patient. “Every approach has unique benefits and risks,” says Michael Borger, MD, PhD, Surgical Director of the Aortic Center. It takes experience to know which treatment will be the right one for each patient.”
The Aortic Center offers the full spectrum of care for both aortic aneurysms and dissections, including the following:
- Open surgical repair of aortic aneurysms and dissections. About two-thirds of aortic procedures are performed through traditional surgery.
- Minimally invasive endovascular stent grafting accounts for about one-third of aortic procedures. These include endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms, and thoracic endovascular aneurysm repair (TEVAR) for thoracic aortic aneurysms. EVAR and TEVAR are performed through catheters rather than open surgery, and afford patients a faster, easier recovery than after open surgery. Surgeons at the Aortic Center also implant special stents with customized bifurcations, or branches, to accommodate smaller arteries branching from the aorta. Few other centers have the advanced expertise to create and implant these specialized stent grafts, which make it possible to treat aneurysms close to the renal arteries.
- Hybrid approaches combine a conventional surgical technique with an interventional or endovascular approach.
Aortic root aneurysms
Treatment of aortic root aneurysms has traditionally required replacement or repair of the aortic heart valve as well as the ascending aortic tissue (the part of the aorta that extends upwards from the heart). However NewYork-Presbyterian surgeons have significant experience utilizing aortic valve-sparing techniques, also known as the David procedure, which allow them to replace the diseased part of the aortic root while preserving the patient’s native aortic valve. Leaving the patient’s aortic valve intact spares patients from limitations and potential complications associated with prosthetic heart valves.
If the patient’s aortic valve is too damaged and needs to be replaced, the program has extensive expertise in the full scope of options, including:
- Replacement of the aortic root and valve with a biologic aortic root-valve conduit developed by surgeons in our program;
- Reconstruction of the aorta and aortic valve with the aid of a human cadaveric aorta;
- The Ross procedure, which entails replacing the diseased aorta and valve with pulmonary tissue;
- Replacement of the entire aortic root and aortic valve with a combination of a mechanical valve with an attached tube graft.
Returning our attention to the numbers, surgeons at the Aortic Center had a 0% mortality rate for elective valve-sparing ascending aortic repair in 2014 and 2015, compared to a national 3% mortality rate. Among patients requiring emergency aortic arch surgery, our program had a 4.7% mortality rate compared to 10.9% mortality across the country. Complications such as renal failure, infection, and stroke were also far below the national average. “When it is you or a loved one in question, those outcomes make a difference,” says Dr. Green.
Elephant trunk procedures
About 11% of patients have aneurysms that affect both thoracic and abdominal sections of the aorta. Co-directors Michael Borger, MD, PhD, and Richard Green, MD, perform the elephant trunk procedure, a two-staged procedure, in certain patients with such complex aneurysms.
The first stage of the elephant trunk procedure prepares the descending aorta in such a way that it will facilitate surgical replacement or stent graft insertion during a second procedure. The timing of the second procedure is dependent on many factors and requires assessment on a patient-by-patient basis. According to Tracy Andrews, the two-part approach is needed because attempting to repair both the thoracic and abdominal portions in a single procedure would require that the patient be under anesthesia for too long and would expose the patient to excessive surgical risk. “The elephant trunk followed by TEVAR or a second surgical procedure reduces the risk of kidney damage and other complications associated with a large, single stage procedure,” says Dr. Borger. “In cases where aneurysms involve the descending thoracic aorta, the elephant trunk followed by TEVAR produces the best outcomes.”
Genetic Testing and Counseling
Along with medical and surgical care, the center provides genetic testing and counseling in order to identify and optimally treat connective tissue disorders and other genetic conditions underlying aneurysmal disease. Geneticist Wendy Chung, MD and the Cardiogenetics program at NYP/Columbia provide the most thorough and sophisticated genetic testing and counseling available in the country. Testing and counseling is extended to family members as well as patients, so that prevention and early detection plans can be implemented. According to Dr. Green, identifying genetic factors underlying aortic disease is crucial to helping the team determine what treatments will be best for which patients.
Monitoring and Surveillance of Aneurysms
Whether or not patients undergo surgery, the Aortic Center at NYP/Columbia offers a unique approach to ongoing surveillance that includes collaboration with internal medicine, cardiology, and other specialties at NYP/Columbia. The multidisciplinary team meets bimonthly to discuss complex cases and offers comprehensive management follow-up with referral providers.
The Aortic Center is committed to nothing less than being the best surgical center in the country for the treatment of aortic aneurysms and dissections. In pursuit of this goal, the center is conducting numerous clinical trials and developing a patient database in order to prospectively study the role of genetics in aortic disease, the safety and efficacy of emerging therapies, and more.