New d-dimer threshold for Japanese patients with suspected pulmonary embolism: a retrospective cohort study

Abstract

Background In the diagnosis of pulmonary embolism (PE), the d -dimer threshold is based on studies conducted in Western countries, where the incidence rate is 5 times higher than that in Asian countries, including Japan. If we could elevate the d -dimer threshold based on the low pre-test probability in the Japanese population, we could omit the computed tomography pulmonary angiography (CTPA) which might lead to radiation exposure and contrast-induced nephropathy. Therefore, we aimed to determine a new d -dimer threshold specific to Japanese individuals. Methods We conducted a retrospective cohort study at an emergency department in Japan, using medical charts collected from January 2013 to July 2017. We included patients whose d -dimer were measured for suspicion of PE with low or intermediate probability of PE and CTPA were performed. The primary outcome was failure rate of the new d -dimer threshold, defined as the rate of PE detected by CTPA among patients with d -dimer under the new threshold ranging from 1000 to 1500 μg/L by 100. The new d -dimer threshold was appropriate if the upper limit of 95% confidence interval of the failure rate of PE was approximately 3%. Results In 395 patients included, the number of patients with PE was 24 (the prevalence was 6.1%). If the d -dimer threshold was 1100 μg/L, the failure rate was 0% (0/119), the upper limit of the 95% confidence interval of the failure rate was 3.1%, and 30% (119/395) of the CTPA might be omitted. Conclusion The new d -dimer threshold could safely exclude PE. This result can be generalized to other Asian populations with a lower incidence of PE. Further prospective studies will be needed.

The Diagnoses and Outcomes of Emergency Patients With an Elevated D-Dimer Over the Next 90 Days

“…Most of the patients in this single-center study were Caucasian. As D-dimer levels can vary in Afro-Caribbean and other racial groups, 15,16 our findings need to be confirmed in an ethnically diverse population. Age influences the level of D-dimer for the diagnosis of venous thromboembolic 17 disease and pulmonary embolus, 18 but it is not known if this is true for other diagnoses or the prediction of mortality.…”

Prognostic Value of D-Dimer in Younger Patients with Pulmonary Embolism

“…Pulmonary embolism (PE) is a common life-threatening condition which contributes to the global burden of cardiovascular diseases in terms of morbidity and mortality (1)(2)(3)(4)(5). The 30-day mortality rate due to PE exceeds 15% (6).…”