18 May Pulmonary Embolism: Evaluation of Age-Adjusted Threshold of D-Dimer Blood Test
MedicalResearch.com Interview with
Scott C. Woller, MD
Co-Director Thrombosis Program
Intermountain Medical Center
Associate Professor of Internal Medicine
University of Utah School of Medicine
Murray, UT 84157-7000
Dr. Woller: By way of background, D-dimer, a simple blood test that is used to investigate the diagnosis of suspected pulmonary embolism (PE), and it increases with age. Recent research suggests that the use of an age-adjusted d-dimer threshold may improve diagnostic efficiency without compromising safety. We wished to assess the safety of using an age-adjusted d-dimer threshold in the work-up of patients with suspected pulmonary embolism.
MedicalResearch: What are the main findings of the study?
Dr. Woller: In this retrospective cohort study we identified 923 patients age > 50 years who presented to our emergency department with suspected pulmonary embolism, and had their pretest probability of PE calculated along with a d-dimer performed. All patients underwent computed tomography pulmonary angiography (CTPA). We observed that among patients unlikely to have PE, adoption of an age-adjusted D-dimer cut-off (compared with a conventional D-dimer cut-off) reduced the need for CTPA in an additional 18.3% of patients, and was associated with a low 90-day rate of failure to diagnose PE.
MedicalResearch: Were any of the findings unexpected?
Dr. Woller: We highlight that among patients age ≥ 75 years, our subgroup analysis demonstrated a 90-day false negative rate of 2.7% (95% CI 0.3-9.3). This observation underscores the importance of prospective randomized controlled study with adequate power to perform subgroup analyses; especially to assure the safety of adopting an age-adjusted d-dimer threshold among the most elderly.
MedicalResearch: What should clinicians and patients take away from your report?
Dr. Woller: Our observations are encouraging that the adoption of an age-adjusted d-dimer threshold is probably safe. However we caution that a prospective study designed with adequate power for pre-specified subgroup analyses to assure the safety of adopting an age-adjusted d-dimer threshold among the oldest patients is essential before this practice is implemented in clinical care.
MedicalResearch: What recommendations do you have for future research as a result of this study?
Dr. Woller: Prospective management studies implementing an age-adjusted D-dimer threshold among patients suspected of pulmonary embolism are ongoing in North America. A prospective management study adopting an age-adjusted D-dimer threshold has been published in Europe (Righini 2014).
Righini M, Van Es J, Den Exter PL, et al. Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study. JAMA 2014; 311:1117-1124