TUESDAY, Feb. 26, 2013 (HealthDay News) -- Ultrasound scans for patients with small abdominal aortic aneurysms may not be required as often as is currently assumed, a new study suggests.
An abdominal aortic aneurysm is an abnormal bulge in the section of the aorta -- the main artery that carries blood from the heart to the rest of the body -- that runs through the abdomen.
"The risk of rupture of abdominal aortic aneurysms increases as the diameter of the aneurysm increases," said one expert not connected to the study, Dr. Mark Adelman.
"If aneurysm ruptures, there is an 80 percent chance that the patient will not survive," said Adelman, who is a vascular surgeon at NYU Langone Medical Center and associate professor at the NYU School of Medicine in New York City. "It is imperative to identify these aneurysms and repair them before they are at high risk for rupture."
Typically, surgery is performed to reduce the risk of rupture in people with large abdominal aortic aneurysms. But researchers who reviewed 18 previous studies involving a total of nearly 15,500 patients concluded that for people with small aortic abdominal aneurysms (less than 2.2 inches in diameter), the risks of surgery are greater than the risk of rupture.
Monitoring with ultrasound scans is recommended for these patients. The researchers, led by Simon Thompson, of the University of Cambridge in England, also noted that most small abdominal aortic aneurysms grow slowly and that surveillance intervals of several years may be acceptable for the majority of patients with smaller aneurysms.
"Current recommendations for surveillance intervals vary widely, although the intervals usually decrease with increasing [aneurysm] diameter," Thompson wrote in the research.
The team said their review findings indicate that for men, gaps between ultrasound scans could range from one to three years, depending on the size of the aneurysm, and, in this scenario, "the risk of rupture would be maintained at less than 1 percent."
This means for a patient with an abdominal aortic aneurysm of just over 1 inch in diameter, "this would reduce the average number of surveillance scans from approximately 15 to seven," the British team said.
They said more research is needed to assess the frequency of monitoring for women with slightly larger aneurysms (just under 2 inches in diameter).
The study "clearly identifies that small aneurysms grow slower than larger aneurysms," Adelman said. "Therefore, the interval between scans should be longer in patients with smaller aneurysms."
"The standard of care in the United States is to image small aneurysms infrequently -- approximately every other year," he said. "Once the aneurysm grows to approximately [1.7 inches], annual ultrasound imaging is typically performed."
Therefore, "the findings in this study confirm the typical practice patterns in the United States, and incur costs of about $200 per year in patients with moderate- to large-sized aneurysms -- a cost effective strategy," Adelman said.
The study appears in the Feb. 27 issue of the Journal of the American Medical Association.
The Society of Interventional Radiology has more about abdominal aortic aneurysm.