CT pulmonary angiography is the go-to test in patients with suspected pulmonary embolism, but many have cautioned radiologists are beginning to overutilize the exam.
Hawaiian researchers warned Wednesday in JACR that a new, stern approach is needed to curb long-term overuse of CTPA. Specifically, the authors suggest patients should have test results showing a higher level of D-dimer protein in their blood before qualifying for the exam.
“Mandated use rather than recommendation of serum D-dimer testing is necessary to improve the utilization of CTPA in the evaluation of patients with suspected acute PE,” corresponding author Hyo-Chun Yoon MD, PhD, of Hawaii Permanente Medical Group’s Department of Radiology, and colleagues wrote July 14.
There are two parts to this issue, Yoon et al. noted: CTPA orders are increasing, particularly in the U.S., and corresponding positivity rates are declining. A Medicare analysis found CTPA use for suspected PE jumped fivefold between 2002 and 2009, yet positivity rates fell from 7.3% to 5.9% during that time.
In August 2021, Hawaii Permanente started recommending an increased D-dimer threshold of 1.0 μg/mL fibrinogen-equivalent units for patients to qualify for CTPA. Individuals were evaluated for potential acute PE in the emergency department between 2010 and 2019.
Yoon et al. looked at 6,013 total studies, comparing PE rates in the two years before and eight years after implementing the new D-dimer guidance.
Over the study period, more patients received a CTPA exam without D-dimer (42.5%) than those with a 1.0 μg/mL threshold (40.2%), the group reported. And 17.2% had serum levels greater than the institution recommended.
There was a short-term positivity rate increase in the years immediately following the medical group’s new recommendations (2013 and 2014). But CTPA orders and positivity percentages quickly fell back to levels seen before the D-dimer update.
Given their findings, Yoon and co-authors believe organizations must take a stronger approach to curb overimaging.
“The failure to mandate the use of serum D-dimer with a higher threshold value for patients who are to undergo CTPA for possible PE has resulted in poor lasting compliance despite promising early results,” the authors wrote. “A firmer approach is likely necessary to yield positive long-term outcomes.”
Read the entire study (behind a paywall) here.
Matt joined Chicago’s TriMed team in 2018 covering all areas of health imaging after two years reporting on the hospital field. He holds a bachelor’s in English from UIC, and enjoys a good cup of coffee and an interesting documentary.