Better Monitoring Aortic Aneurysms

Ultrasounds with contrast provide enhanced monitoring for aortic aneurysms

(RxWiki News) Imaging has overwhelmingly proved an effective means of monitoring patients after medical procedures. It's non-invasive and allows doctors to monitor for complications. It just boils down to determining which type of imaging is most effective for certain patients.

For patients receiving an endovascular repair procedure for an abdominal aortic aneurysm, contrast-enhanced ultrasound appears to offer the safest and most accurate monitoring.

"Talk to a vascular surgeon about the type of monitoring used after procedures."

Rosa Gilabert, MD, PhD, from the Hospital Clinic at the University of Barcelona in Spain, said that the findings of a recent study support adding contrast-enhanced ultrasound as an additional tool in follow up procedures of patients receiving treatment for an abdominal aortic aneurysm.

During an abdominal aortic aneurysm, the large blood vessel that supplies blood to the abdomen, pelvis and legs becomes abnormally large or begins to balloon outward. The aneurysm stresses the wall of the aorta and can lead to a fatal rupture.

Abdominal aortic aneurysms are most common in men over the age of 60 with risk factors such as smoking, hypertension, high cholesterol, obesity, peripheral vascular disease or a family history of heart disease.

The treatment -- endovascular repair of abdominal aortic aneurysms (EVAR) -- includes implanting a stent graft called an endograft in the blood vessel to bypass the weakened area of the aorta and prevent rupturing.

The procedure requires monitoring afterward though because a complication called endoleak can cause a subsequent rupture.

Doctors usually monitor patients that receive the surgery with computed tomography (CT) angiography, but it exposes patients to ionizing radiation and puts them at risk of kidney damage from the contrast agent.

Researchers decided to study ultrasound with a second-generation contrast agent and software as a safer, more accurate alternative to CT angiography. The contrast agent is comprised of a suspension of microbubbles about the size of red blood cells. Their size prevents them from passing through cells lining the inner surface of blood vessel walls. Additionally, the method offers dynamic real-time monitoring.

During the study, the technique was evaluated in 35 patients who underwent EVAR. The patients received the usual CT angiography and the contrast-enhanced ultrasound one month and six months after the procedure, followed by annual follow ups. In total, 126 CT angiography and contrast-enhanced ultrasound studies were performed.

Investigators found that contrast-enhanced ultrasound had a sensitivity of 97 percent, a specificity of 100 percent and an accuracy of 99 percent for endoleak detection. The technique helped doctors correctly classify of 26 of 33 endoleaks. Though a handful were not correctly classified, they did not miss any clinically important endoleaks.

"The main advantage of contrast-enhanced ultrasound is that it offers the possibility of real-time exploration of EVAR-treated patients, without the exposure to ionizing radiation or the risk of damage to the kidneys," Dr. Gilabert said. 'To avoid the potential risk of kidney toxicity is particularly important, because impaired renal function is not uncommon in these patients."

The study was recently published in journal Radiology.

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Review Date: 
May 8, 2012