NEW YORK (Reuters Health) – Algorithms that combine a clinical decision rule (CDR) and highly sensitive D-dimer are widely recommended for identifying patients in whom pulmonary embolism can be safely excluded without further studies, but these algorithms appear to be underused, according to a survey of practitioners in the Veterans Administration (VA) healthcare system.
“Based on the survey results, only half of the regional VA sections are utilizing the recommended clinical decision rule/D-dimer approach in the use of CT pulmonary angiography (CTPA),” Dr. Nancy Hsu from the Greater Los Angeles Veterans Affairs Healthcare System told Reuters Health by email. “The actual utilization may be even lower, as the survey was not designed to determine the extent of adherence.”
Previous studies have shown that adherence to CDR/D-dimer algorithms is poor, with some estimating that over half of CTPA are obtained outside of guideline recommendations.
Dr. Hsu and Dr. Guy W. Soo Hoo used an Internet-based questionnaire of practitioners within the VA healthcare system to determine the utilization of CDR and D-dimer testing before obtaining CTPA or a ventilation-perfusion (V-Q) scan in the evaluation of patients with suspected pulmonary embolism.
Of the 18 total regional Veterans Integrated Service Networks (VISNs) that responded to the survey, only nine reported at least one site that required a CDR before CTPA. One additional site requires the use of a D-dimer but not of a CDR, and the remaining VISNs lacked even a single facility that used either assessment.
Of the 120 respondents, 85% did not require results of a CDR or D-dimer testing before ordering a CTPA, 6.7% required both a CDR and D-dimer, 5.8% required only a CDR, and 2.5% required only a D-dimer, the researchers report in the Journal of the American College of Radiology, online October 31.
The estimated average CTPA yield for pulmonary embolism was 12.0% when both CDR and D-dimer were used, 8.0% when only CDR was used, 3.0% when only D-dimer was used, and 8.3% when there were no requirements for ordering CTPA.
“Although adherence to best-practice recommendations for the use of CTPA has been suboptimal, the magnitude of nonadherence was surprising,” Dr. Hsu said. “The VA is its own healthcare system, but its practices often reflect those in the surrounding community, and the VA is often a leader in best practices and guideline-recommended care.”
“In our experience, frequent education, feedback, and reminders to physicians, incorporation of CDR/D-dimer use into the order entry menu, and local champions (including radiologists) of the algorithm are all needed for sustained adherence,” she said.
“These results warrant further investigation and comparison of CTPA actual utilization and yield rather than respondent estimates in sites with and without a diagnostic algorithm in place,” the authors conclude. “Further efforts are also needed to identify the barriers to implementation of these guidelines, which was beyond the scope of our survey.”
“This type of information will contribute to a better understanding of clinical decision making, which in turn will allow more efficient and effective care of patients undergoing evaluation for suspected pulmonary embolism,” they add.
J Am Coll Radiol 2019.