Screening for Aortic Aneurism

In more affluent areas of the USA , mobile units are offering to screen older people for a number of diseases (and for considerable sums of money!). One of these screens is usually an ultrasound exam for abdominal aortic aneurism (AAA). Should you have such a screen? Or should your health provider provide free screening? AAA occurs in 5% to 10% of men aged 65 to 79. The major complication is rupture, which presents as a surgical emergency, and carries an 80% mortality (50% if they reach the operating room). Diagnosis before rupture, therefore, would appear to be a good idea.

A publication in the Cochrane Database Systematic Review presents information from 4 studies of the clinical value of ultrasound screening. Data came from 125,000 men and 9,300 women who had been screened between 3 to 5 years earlier. The analysis found that there was a significant decrease in mortality from AAA in men, but not in women; men, but not women, had a decreased frequency of ruptured aneurism. The investigators say the numbers of women in the data base were too small to allow a benefit of screening to emerge.

Screening reveals quite a number of people with aortic aneurisms, but the guiding experts believe that surgery (in the absence of symptoms) is only justified if the diameter is estimated to be greater than 5.5 centimeters. Ultrasound should be repeated twice a year if smaller aneurisms are found, with referral for surgery if the aneurism grows over 1 cm a year or reaches 5.5 cm. Surgery caries a significant mortality, so that those living through the ‘less than 5.5 cm’ must have considerable anxiety. Newer approaches to treatment, such as endoscopic repair (i.e. through an artery, like stenting via cardiac catheterization) also carry similar risks to the open surgical approach. All this makes for difficult personal decisions . . .