Age-Adjusted D-dimer Threshold Strategy for VTEs in Suspected PE

Quick Takes

  • An integrating the YEARS score with age-adjusted D-dimer thresholds was noninferior to age-adjusted D-dimer threshold only for VTE detection.
  • Integrating the YEARS score with age-adjusted D-dimer thresholds reduced the use of chest imaging for PE diagnosis in the ED.
  • Efforts are needed to successfully implement a clinical diagnostic strategy that integrates the YEARS score and age-adjusted D-dimer threshold for PE diagnosis.

Study Questions:

Is a strategy that combines the YEARS rule with the pulmonary embolism (PE) rule-out criteria (PERC) rule and an age-adjusted D-dimer threshold valid for patients with suspected PE?

Methods:

The authors conducted a cluster-randomized, crossover, noninferiority trial in 18 emergency departments (EDs) in France and Spain. Patients who were at low clinical risk for PE but not excluded by the PERC rule and patients at intermediate clinical risk of PE were included between October 2019 and June 2020, following their course until October 2020. Centers were randomized to exclude PE without chest imaging using one of two strategies. In the control group, PE was ruled out if the D-dimer was less than the age-adjusted threshold (500 ng/ml for age <50 years, age x 10 for age ≥50 years). In the intervention group, PE was ruled out if the D-dimer was below an elevated level (<1000 ng/ml) for patients with 1+ YEARS criteria or the D-dimer was below an age-adjusted threshold. The primary endpoint was detection of venous thromboembolism (VTE) within 3 months.

Results:

Among the 1,414 patients (mean age 55 years, 58% female), 1,217 (86%) were analyzed in the per-protocol analysis. PE was diagnosed in the ED in 100 patients (7.1%). At 3 months, VTE was diagnosed in one patient in the intervention group (0.15%; 95% confidence interval [CI], 0-0.86%) versus five patients in the control group (0.8%; 95% CI, 0.26%-1.86%) with an adjusted difference of -0.64% (within the noninferiority margin). Two key secondary endpoints included less chest imaging (30.4% vs. 40.0%; adjusted difference, -8.7%; 95% CI, -13.8% to -3.5%) and ED length of stay (6 hours vs. 6 hours; adjusted difference, -1.6 hour, 95% CI, -2.3 hours to -0.9 hour).

Conclusions:

The authors concluded that ED patients with suspected PE managed using the YEARS rule combined with an age-adjusted D-dimer threshold for PERC-positive patients was noninferior to a conventional diagnostic strategy relying only on the age-adjusted D-dimer threshold.

Perspective:

Multiple studies have explored various algorithms and risk scores to identify which patients with suspected PE do not require chest imaging. This study combines a number of commonly used strategies to identify a best clinical diagnostic pathway that reduces unnecessary chest imaging. By first assessing the YEARS score (pregnancy, clinical signs of deep vein thrombosis, hemoptysis, and PE as the most likely diagnosis), then applying either high D-dimer threshold (<1000 ng/ml for YEARS score of 0) or an age-adjusted D-dimer threshold (for YEARS score ≥1) results in a low rate of subsequent VTE events, fewer chest imaging procedures, and shorter ED length of stay. Challenges in implementation will be to change clinician behavior and operationalizing a two-step decision process that integrates clinical factors (YEARS criteria) and laboratory thresholds (D-dimer). If EDs can successfully implement this multi-step process, they can successfully reduce unnecessary chest imaging and shorten ED length of stay, while safely caring for patients.

Clinical Topics: Anticoagulation Management, Cardiovascular Care Team, Noninvasive Imaging, Prevention, Pulmonary Hypertension and Venous Thromboembolism, Vascular Medicine, Anticoagulation Management and Venothromboembolism

Keywords: Anticoagulants, Diagnostic Imaging, Emergency Service, Hospital, Fibrin Fibrinogen Degradation Products, Length of Stay, Pulmonary Embolism, Risk Factors, Secondary Prevention, Vascular Diseases, Venous Thrombosis, Venous Thromboembolism


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