Abdominal Aortic Aneurysm: When It’s Surgery Time
PEOPLE WHO DON’T realize they’re living with an abdominal aortic aneurysm may face a sudden aortic rupture or tear and massive, catastrophic bleeding. However, others lucky enough to know in advance that they have a small, stable AAA have the luxury of time to consider their treatment choices – from watchful waiting to a minimally invasive procedure to all-out open surgery. Here’s how doctors and patients decide when and what type of elective surgery would be wise.
Major Artery at Risk
The aorta is the large, central artery that carries blood from the heart to your body. The upper section within the chest is the thoracic aorta, and the lower section is the abdominal aorta. Because the aorta receives pressure with each heartbeat, parts of the aorta’s wall can gradually weaken in people at risk. Aortic dissection involves a tear in the aorta’s wall, causing the layers to separate. Aneurysm, a bulge or ballooning in the artery wall, is more common in the abdominal aorta. A ruptured abdominal aortic aneurysm is a medical emergency.
By diagnosing an AAA early, while it’s still small, doctors can carefully monitor patients while treating their risk factors – known as watchful waiting.
“Most aneurysms are diagnosed with imaging studies that are done for some other reason,” says Dr. Benjamin Starnes, a professor and chief of the vascular surgery division at the University of Washington. “The patient will typically come in because they’ve had an X-ray or they’ve had an ultrasound study for some other completely unrelated condition, and oh, by the way, they found out that they have this aneurysm.”
Certain risk factors make you much more vulnerable: being male, 65 or older, a smoker and having high blood pressure or a hardening of the arteries. A family history of AAA also raises your risk. Medical management may keep an AAA under control for years, through watchful waiting, regular imaging studies, lifestyle changes and medication.
Women’s risks are closer to men’s at younger ages, says Dr. James Black, chief of the division of vascular surgery at Johns Hopkins Hospital. However, at 65 and beyond, AAA risk “clearly predominates” for men, he says. But “the problem is while aneurysms are more infrequent in women, they have a higher risk for rupture,” he says. “So we sometimes get more nervous about aneurysms in women than we do in men.”
Balance Shifts to Surgery
Elective surgery is far preferable to emergency surgery, and most patients do well afterward. The question is when to have it.
“The most important predictor of aneurysm rupture is the diameter of the aneurysm,” says Dr. John Eidt, vice chair of vascular surgery at Baylor University Medical Center in Dallas. “Just like the diameter of a balloon, if it reaches some critical point, it’s likely to burst.” As for shape, fusiform aneurysms, shaped somewhat like a football, are probably a little less likely to burst than sac-shaped aneurysms, Eidt says.
Doctors use serial imaging to see whether an aneurysm is growing and how quickly. “We like to intervene if we see significant change,” Eidt says. “We’ll look at patients every six months or every year in order to be able to plot on a curve, a growth curve or an enlargement curve.”
The onset of symptom is ominous. “Occasionally, aneurysms will actually start to cause pain as they’re rapidly enlarging or sort of pre-rupture,” Eidt says. “That, we think, is a very important finding. It predicts a risk of rupture and would almost always cause us to intervene.”
The patient’s unique history – including age, sex and overall health – is an important piece of the puzzle. “If you’re young, you’re more likely to get your aneurysm fixed than if you’re old,” Eidt says.
Doctors use serial imaging to see whether an aneurysm is growing and how quickly. “We like to intervene if we see significant change,” Eidt says. “We’ll look at patients every six months or every year in order to be able to plot on a curve, a growth curve or an enlargement curve.”
The onset of symptom is ominous. “Occasionally, aneurysms will actually start to cause pain as they’re rapidly enlarging or sort of pre-rupture,” Eidt says. “That, we think, is a very important finding. It predicts a risk of rupture and would almost always cause us to intervene.”
The patient’s unique history – including age, sex and overall health – is an important piece of the puzzle. “If you’re young, you’re more likely to get your aneurysm fixed than if you’re old,” Eidt says. “Your risk of lifetime rupture is higher.”
Coexisting conditions, such as heart, lung or kidney disease, raise the stakes of undergoing surgery, Eidt says: “If your natural history of the [aneurysm] is not very bad, and your risk of the procedure seems excessive because of comorbidities, then we kind of push up the size of the aneurysm that you would reasonably treat.”
Selecting Your Surgeon
Vascular surgeons specialize in procedures involving the thoracic aorta, major arteries and veins. Cardiothoracic surgeons specialize in procedures involving the heart and thoracic aorta. Board certification is one measure of a surgeon’s qualifications. You can check a surgeon’s certification status through the American Board of Surgery website.
Patients should feel free to ask questions about qualifications and experience. “I don’t think it’s at all unreasonable to say to a doctor, ‘Well, how many of these have you done?'” Eidt says. “‘How many do you do on an annual basis? And can you tell me how many of these are done in your hospital?'”
In addition, patients need to trust and feel at ease communicating with their doctors, who should be able to explain the AAA’s status, treatments choices and risks in ways they can readily understand.
“I almost always show the CT scan to the patient in real time,” Eidt says. “We sit at the co
mputer monitor and look at the CT scan together.” Current technology allows 3-D reconstructions, he adds. “So I can show you an aneurysm as clear as if we were in Jamaica looking out at the ocean.”
Picking Your Procedure
Surgical options for aneurysm include traditional open surgery and less-invasive endovascular repair.
Endovascular repair is performed under either general or local anesthesia. A stent – a thin metal tube that makes up the core of a “stent graft” – is guided through the femoral artery toward the area of the aneurysm.
“You don’t remove the aneurysm, but you put a liner – essentially a spring-loaded fabric sleeve – inside the aneurysm that essentially reinforces the inside,” Eidt says. “It prevents the blood pressure from causing the aneurysm to enlarge or rupture.” Recovery is shorter and easier with this option. Patients can usually leave the hospital in the next one or two days.
Black, however, notes that correct fit can be an issue with stents, and not all patients are good candidates. Patients must be willing to come back regularly, usually yearly, for a CT scan to make sure the device is working well.
Open surgery is always done under general anesthesia. A large incision is made straight down the middle of the abdomen, across the abdomen or to the side. The aneurysm is isolated between surgical clamps and opened, and a synthetic graft is sewn into place to replace the weakened part of the aorta. Surgical risks include bleeding, graft or wound infection, kidney perforation and blood clots.
It’s important to realize that open surgery is “a big operation,” Eidt says, with patients taking weeks or even months to fully recover. The trade-off is that results may be longer-lasting. “When you complete the operation, patients almost never have a problem with the procedure – it’s sort of a one and done and you do well,” he says.
Based on your age, aneurysm status, co-existing conditions, general health and personal preference, your medical team will help you decide the right treatment for you.
Risk Statistics
A study published in the September 2016 issue of JAMA Surgery compared early death rates for elective AAA repair procedures. “Overall, in-hospital mortality was 0.7 percent for [endovascular repair] and 3.8 percent for [open AAA repair],” researchers found. Other studies find fewer major complications with endografts in the short term, but by two years and on, survival rates are comparable.
“Endovascular repair is not, as yet, a panacea,” an accompanying commentary notes. “Endovascular AAA repair has yet to rid itself of troubling endoleaks, need for re-interventions and persistent (albeit low) risk of AAA rupture.”
Choosing Your Hospital
Abdominal aortic aneurysm open repair was among a handful of high-risk treatments evaluated by The Leapfrog Group to determine key factors for appropriate, error-free hospital care. Leapfrog concluded that AAA surgery is safer in hospitals where the volume performed is 50 or more cases a year. The U.S. News Best Hospitals ratings now include abdominal aortic aneurysm repair as one of nine common procedures and conditions in which hospital performance is evaluated.
Today, Eidt says, somewhere between 75 to 80 percent of all AAAs are treated with endografts as opposed to open repairs.
One way to find hospitals with high volume and advanced expertise in both procedures is to look for aortic disease centers or aortic centers of excellence that focus on conditions like AAA.
Most big hospitals, Eidt says, have endovascular operating rooms. These, he says, are “specially designed hybrid spaces where people can do a combination of open surgery and endovascular surgery, which is increasingly frequent in the management of these complex aortic cases.”
However, he adds, some small community hospitals “deliver a very high standard of care with very good results in the treatment of patients with abdominal aortic aneurysm. So, therefore, the size of the hospital per se is not a measure.”
Source: healthnews
