Diagnosis of pulmonary embolism in the elderly: adherence to guidelines and age-adjusted D-dimer concentration values.

Objectives . The main purpose was to assess our emergency department's level of adherence to clinical practice guidelines (CPGs) for the diagnosis of pulmonary embolism in different age groups. The secondary aims were to study the utility and estimated the number of avoidable CT angiography with this approach of age-adjusted D-dimer concentrations in combination with the Wells score in the diagnosis of pulmonary embolism. Material and methods Retrospective observational study of a series of hemodynamically stable patients suspected of having pulmonary embolism in the emergency department of a tertiary care university hospital in 2012. Cases were identified in hospital discharge records on the basis of orders for D-dimer assays and computed tomography (CT) angiography of pulmonary arteries justified by suspicion of pulmonary embolism. We analyzed the degree of adherence to CPGs according to age groups, calculated the specificity and sensitivity of combining age-adjusted D-dimer test results and the Wells score, and estimated the number of potentially avoidable CT angiography procedures. Results We found a total of 785 patients (mean age, 69 years; range, 18-97 years) suspected of having pulmonary embolism; 403 (51.3%) were women. Significant differences were detected in adherence to CPGs, depending on which clinical prediction models were used and patient age (50 years or younger, 69.7%-76.5% adherence; 65-74 years, 32.3%-53.2%; 75-84 years, 29.1%-46.8%; 85-89 years, 32.7%-41.8%; and 90 years or older, 24.4%-46.7%). Adherence was increased when D-dimer test result and the simplified Wells score were combined (increments of 10.4%, 8.0%, 13.6%, 11.1%, respectively in the following age groups: 65-74 years, 75-84 years, 85-89 years, and 90 years or older). Using an ageadjusted D-dimer cut-point increased diagnostic specificity (34.2% without such a cut-point vs 45.8% with one). The positive predictive value of the test also increased when an age-adjusted D-dimer cut-point was used (to 11.4%, from 9.6% without age adjustement). Seventy CT angiograph procedures (12.5%) could have been avoided by using age-adjusted cut-points. Conclusion We observed different degrees of age-related adherence to CPGs in cases in which pulmonary embolism was suspected. Using the simplified Wells score combined with an age-adjusted cut-point for D-dimer assay positivity improved the specificity and positive predictive value of the D-dimer assessment in comparison with standard practice. Using age-adjusted D-dimer cut-points could decrease the number of pulmonary artery CT angiograms required.