Abdominal aortic aneurysms (AAA) can lead to life-threatening rupture—requiring emergency surgery with mortality rates nearing 90 percent. But AAA are difficult to diagnose before rupture, limiting clinical research in decreasing the 13,000 related deaths in the United States each year.
Ultrasound has been an effective method of detecting AAA, leading to the U.S. Preventative Services Task Force (USPSTF) recommending its B-level use on men between 65 and 75 who had ever smoked in 2005. The USPSTF updated those guidelines in 2014, recommending adding C-level screening for non-smoking men of the same age.
New research published online in the Journal of the American College of Radiology examined whether the updated USPSTF guidelines have affected AAA ultrasound screenings in terms of volume and patient diversity. The team—led by Evan Zucker, MD, clinical assistant professor of radiology at Stanford University—also investigated differences in detection rates and size of aneurysms at diagnosis.
“As AAA screening continues to garner support, radiologists can assist in ferreting out inappropriate examinations while guiding referring physicians/providers on appropriate follow-up and management for newly detected AAAs and a broad spectrum of incidental findings,” Zucker and colleagues wrote.
The retrospective study examined radiologic and clinical data from Massachusetts General Hospital (MGH) from March 2013 to September 2015, covering 15 months before and after the updates to the USPSTF guidelines.
The cohort included 831 AAA screenings—417 before the new guidelines and 414 after, with a mean patient age of 67.9 years. Patients were overwhelmingly male (89.2 percent). A total of 602 examinations were considered appropriate, with 62 AAAs detected (7.5 percent).
Researchers discovered no significant change in volume, patient demographics or rates of incidental findings. The proportion of men who ever smoked increased from 60.7 percent to 69.1 percent of examinations. The rate of appropriate screenings also increased after implementation of the new guidelines, up to 75.6 percent from 69.3 percent.
“Contrary to our hypothesis, the period after the release of the revised USPSTF guidelines did not demonstrate increased examination volumes or demographic diversity,” Zucker and colleagues wrote. “In fact, the proportion of male never-smokers aged 65 to 75 years, in whom the revised guidelines are ostensibly more inclusive of screening, counterintuitively declined from 8.6 percent before to 4.3 percent after their release.”
Detection rates nearly doubled with the new guidelines, from 5.5 percent to 9.4 percent. The average size of an aneurysm decreased from 3.8 centimeters to 3.3 cm, indicating earlier detection.
“Radiologists have a potential opportunity to assist in generating clearer AAA follow-up guidelines and helping clinicians ensure that recommendations are followed, through electronic communications or otherwise,” Zucker et al. wrote.