Novel imaging technology provides GPS system to help guide surgeons
Each year, nearly 40,000 Americans undergo elective surgery to repair an abdominal aortic aneurysm. Sometimes referred to as AAA (“triple A”), this condition develops when a portion of the aorta, the main blood vessel carrying blood from the heart to the lower part of the body, becomes enlarged and starts to bulge. Marc Schermerhorn, MDLeft untreated, this condition can lead to a dangerous and often fatal turn of events.
“Large aneurysms, five centimeters in diameter or larger, or those that are fast-growing, could weaken the aortic wall and eventually rupture,” explains Marc Schermerhorn, MD (right), Chief of Vascular and Endovascular Surgery in the CardioVascular Institute at Beth Israel Deaconess Medical Center and Associate Professor of Surgery at Harvard Medical School. “This is a life-threatening situation.”
Schermerhorn recommends that aneurysms be repaired before they pose a problem. Repairs can be made surgically, through bypass grafting, or with a minimally invasive option called endovascular aortic repair (EVAR).
EVAR Proves Safe and Durable
In a study published in the New England Journal of Medicine
in 2015, Schermerhorn and a group of BIDMC researchers compared EVAR with open surgical repair. They found that not only is the less invasive EVAR safe and durable, but that EVAR outcomes have been improving over time.
“Over the past 15 years we’ve seen the number of EVAR cases steadily increase, and today more than 75 percent of all AAA patients in the U.S. are able to have aneurysms repaired using this minimally invasive approach,” says Schermerhorn. “Because incisions are smaller, there is less pain and less risk of complications with EVAR than with open surgical procedures.”
illustration of abdominal aortic aneurysm (AAA)EVAR also results in shorter hospital stays and faster recovery times than traditional surgery.
Before treatment, AAA patients first undergo a computed tomography (CT) imaging scan.
“We insert dye prior to the scan so that we can see clearly see the aorta and its branches to determine whether a repair is needed and what type of repair is best for the patient,” says Schermerhorn. “If it is determined that EVAR and a stent-graft are a patient’s best treatment option, the CT scan provides the surgeon with information necessary to choose specific grafts.”
For the minimally invasive EVAR procedure, a thin tube known as a catheter is inserted through a small puncture in the patient’s groin. Using the catheter, the surgeon navigates to the aorta to position a “stent-graft.” Made of fabric supported by a wire ”scaffold,” the stent reinforces the weak spot in the aortic wall and diverts blood flow so that it creates an internal bypass through the aneurysm.
A GPS System for the Blood Vessels
Endovascular AAA surgeries are now even more precise thanks to an advanced 3-D imaging technology developed by engineers at Philips Healthcare in the Netherlands with feedback from Schermerhorn.
Known as the Vessel Navigator system, the imaging technology couples 3-D vascular anatomical information from preoperative imaging scans with a live X-ray image called a fluoroscopy, which is recorded during the EVAR procedure. Together, these two critical pieces are overlaid to provide surgeons with a 3-D “roadmap” to guide them through the patient’s vasculature with extreme precision.
“The 3-D Vessel Navigator roadmap can be rotated at any angle and follows the movement of the X-ray beam and the table where the patient is lying,” explains Schermerhorn. “This provides surgeons with unique views of the patient’s vasculature — in real time — so they can execute even the most complex aneurysm repairs.”
In a study published in the Journal of Vascular Surgery, Schermerhorn and colleagues showed that, compared to conventional imaging techniques, Vessel Navigator offered patients and surgeons four important benefits:
- It significantly reduced radiation exposure for patients and providers.
- It reduced X-ray fluoroscopy time.
- It minimized the dose of contrast dye (which can cause serious side effects among some patients).
- It shortened overall procedure time.
“These benefits are particularly important as growing numbers of AAA patients with more complex conditions become eligible for treatment,” says Schermerhorn. “The Vessel Navigator technology offers so many advantages that I consider it indispensable and now use it on all aortic interventions.”
He adds, “Our hope is to continue to develop new technologies aimed at making vascular interventions better and safer for patients worldwide.”
Above content provided by the CardioVascular Institute at Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.
Abdominal Aortic Aneurysm
Causes & Risk Factors
Most aortic aneurysms are caused by a breakdown in the proteins that provide structural strength to the aorta's wall. Some risk factors that contribute to this structural breakdown include:
- Age – individuals over 60 are most likely to develop this condition
- Gender – males are more prone to the condition than females
- History of atherosclerosis (hardening of the arteries)
- Family history of AAAHistory of smoking
- High blood pressure
- Chronic lung disease
Most people feel no symptoms. AAA is often detected when tests are conducted for unrelated reasons. Those with symptoms describe them as:
- A pulsing feeling in the abdomen
- Unexplained severe pain in the abdomen or lower back
Source: Society for Vascular Surgery