Assessing 2 d-dimer age-adjustment strategies to optimize computed tomographic use in ED evaluation of pulmonary embolism

Abstract

Study Objective Validate the sensitivity and specificity of two age adjustment strategies for D-dimer values in identifying patients at risk for pulmonary embolism (PE) compared to traditional D-dimer cutoff value (500ng/mL) to decrease inappropriate computed tomography pulmonary angiography (CTPA) utilization. Methods This institutional review board-approved, HIPAA-compliant retrospective study included all adult emergency department (ED) patients evaluated for PE over a 32-month period (1/1/11–8/30/13). Only patients undergoing CTPA and D-dimer testing were included. We used a validated natural language processing algorithm to parse CTPA radiology reports and determine presence of acute PE. Outcome measures were sensitivity and specificity of two age-adjusted D-dimer cutoffs compared to the traditional cutoff. We used chi-square tests with proportional analyses to assess differences in traditional and age-adjusted (age × 10 ng/mL) D-dimer cutoffs, adjusting both by decade and by year. Results A total 3,063 patients with suspected PE were evaluated by CTPA during the study period and 1,055 (34%) also received D-dimer testing. The specificity of age-adjusted D-dimer values was similar or higher for each age group studied compared to traditional cutoff, without significantly compromising sensitivity. Overall, had decade age-adjusted cutoffs been used, 37 CTPAs could have been avoided (19.6% of 189 patients aged >60 with Wells score ≤4); had yearly age-adjusted cutoffs been used, 52 CTPAs (18.2% of 286 patients aged >50 with Wells score ≤4) could have been avoided. Conclusion Each age-adjusted D-dimer cutoff strategy for the evaluation of PE was associated with increased specificity and statistically insignificant decreased sensitivity when compared to the traditional D-dimer cutoff value.

Natural Language Processing Technologies in Radiology Research and Clinical Applications

“…One study confirmed the recommendations of a prospective European trial to improve the low specificity of d-dimer for determining appropriate use of CT pulmonary angiography for ruling out acute pulmonary embolism in aging populations (39). Using an NLP framework named GATE (General Architecture for Text Engineering) with an accuracy of 98% in detecting pulmonary embolism compared with manual review, the authors were able to quickly validate two age-adjusted d-dimer cutoffs in a U.S. population (39). Dunne et al (40) used the same NLP system to assess the effect on the use and yield of CT pulmonary angiography in inpatients with suspected pulmonary embolism before and after implementation of a CDS system that uses evidence-based guidelines to assist in making the decision to order a study.…”

“…One study confirmed the recommendations of a prospective European trial to improve the low specificity of d-dimer for determining appropriate use of CT pulmonary angiography for ruling out acute pulmonary embolism in aging populations (39). Using an NLP framework named GATE (General Architecture for Text Engineering) with an accuracy of 98% in detecting pulmonary embolism compared with manual review, the authors were able to quickly validate two age-adjusted d-dimer cutoffs in a U.S. population (39).…”

Yield of CT Pulmonary Angiography in the Emergency Department When Providers Override Evidence-based Clinical Decision Support

“…The population of this retrospective cohort study included all patients suspected of having PE (including pregnant patients) who presented to the ED and underwent CT pulmonary angiography during the study period. All 2993 CT pulmonary angiographic studies (2655 unique patients) have been previously reported on (22). The previous study evaluated age-adjustment strategies for d-dimer values in the diagnosis of PE at CT pulmonary angiography; in contrast, the current study addresses the yield of CT pulmonary angiography when providers override evidencebased CDS alerts.…”

Which age‐adjusted D‐dimer cut‐off performs best?

“…age in years times 10, 1 age in years times 16, 2 and decade-specific levels with cut-offs of 500 μg/L for age less than 60years, 600 μg/L for age 61-70 years and 700 μg/L for age 71-80 years. 3 To test the diagnostic performance of these, we conducted a retrospective cohort study by medical records review of patients having both D-dimer and CTPA for investigation of suspected PE. This planned sub-study had the additional eligibility criteria of age ≥50 years and assessment as low risk by the simplified Wells' score.…”