Age-adjusted D-dimer testing improves ability to rule out PE

(HealthDay)—Compared with fixed D-dimer testing, age-adjusted D-dimer testing is associated with an increase in the proportion of patients with suspected pulmonary embolism (PE) in whom imaging can be withheld, according to a review published online May 17 in the Annals of Internal Medicine.

Nick van Es, M.D., from the Academic Medical Center in Amsterdam, and colleagues used data from six prospective studies to examine and compare the efficiency and safety of the Wells rule with fixed or age-adjusted D-dimer testing. Data were included for 7,268 inpatients and patients with cancer, chronic obstructive pulmonary disease, previous venous thromboembolism, delayed presentation, and age 75 years or older.

The researchers estimated the proportion of patients in whom imaging could be withheld based on a "PE-unlikely" Wells score and a negative D-dimer test result (efficiency) using fixed and age-adjusted D-dimer thresholds. They also estimated the three-month incidence of symptomatic venous thromboembolism (failure rate). When the age-adjusted D-dimer threshold was applied (instead of fixed), efficiency increased from 28 to 33 percent. Elderly patients had a more prominent increase (12 percent), while inpatients had a less prominent increase (2.6 percent). In all examined subgroups, the failure rate of age-adjusted D-dimer testing was less than 3 percent.

"This strategy seems safe across different high-risk subgroups, but its efficiency varies," the authors write.