Use of CTPA for suspected pulmonary embolism in pregnancy surges 156% at 2 hospitals

The use of advanced imaging for suspected pulmonary embolism in pregnancy leapt 72% over a 10-year period at two academic medical centers, according to a new analysis published Wednesday.

Delivery of computed tomography pulmonary angiography, or CTPA, has driven this change, increasing by 156% between 2007 and 2016. At the same time, use of the alternative lung scintigraphy for suspected pulmonary embolism fell by more than 77%, researchers discovered.

Despite the marked increase, there was no corresponding uptick in either positive PE readings or pregnancies, researchers wrote Sept. 27 in JACR.

“Although the detection rate of PE on advanced imaging has decreased, the utilization rate amongst pregnant patients doubled during this period,” lead author Sameer K. Goyal, MD, with the Department of Radiology at Northwell Health, and colleagues concluded. “These results highlight the need to consider the radiation risks and costs of advanced imaging in specific patient populations.”

Pulmonary embolism is one of the most common causes of death in pregnancy, with a mortality rate as high as 20%, the authors noted. However, diagnosing this concern can be difficult, as symptoms may mimic normal physiological changes in pregnancy. CTPA is a key diagnostic tool for PE, but it comes with possible radiation risk to the mother and her child. Given such concerns, six medical societies recommend lung scintigraphy as the preferred primary imaging modality.

To better understand this issue, researchers retrospectively evaluated pregnant women who underwent advanced imaging for suspected PE at two New York hospitals between 2007 to 2016. The final sample included 707 pregnant patients, with 92.5% receiving CTPA and 7.5% evaluated using lung scintigraphy. There was an average increase of about 5.2 advanced imaging studies each year, jumping from 61 in 2007 to 105 by the end of the study period. Goyal et al. also calculated an average increase of 0.08 studies per 1,000 local pregnancies each year, doubling from 0.7 to 1.4 over a decade. Conversely, there was a decrease of 0.004 in the number of imaging studies positive for PE, falling from 3% to 0% in 2016.

CTPA use increased by about 6.5 scans per year, more than doubling from 2007 to 2016, while lung scintigraphy dropped by an average of 1.3 exams each year.

Previous studies have shown promise in using diagnostic algorithms to help curb the need for advanced imaging in pregnant patients with suspected PE. Such tools use D-dimer test results, clinical prediction rules and compression ultrasound prior to progressing to CTPA, the authors noted.

“Multiple societal-level guidelines recommend application of these tools prior to advanced imaging,” Goyal and co-authors wrote. “Given the increased imaging observed in this study and others, application of these tools in pregnancy may be of high value. Because pregnant patients are at heightened risk of malignancy from radiographic imaging due to proliferating breast tissue, diagnostic algorithms designed to reduce the need for advanced imaging while retaining accuracy should be further examined and incorporated into clinical practice.”

Find the full pre-proof study in JACR at the link below.