title: Accuracy of D-dimer:fibrinogen ratio to diagnose pulmonary thromboembolism in patients admitted to intensive care units.
abstract: BACKGROUND
  Pulmonary thromboembolism (PTE) may increase D-dimer and decrease fibrinogen levels. However, in settings such as intensive care units (ICU) and in long-term hospitalised patients, several factors may influence D-dimer and fibrinogen concentrations and make them unreliable indicators for the diagnosis of PTE. The aim of this study was to evaluate the accuracy of D-dimer:fibrinogen ratio (DDFR) for the diagnosis of PTE in ICU patients.
  
  
  METHODS
  ICU patients who were suspected of having a first PTE and had no history of using anti-coagulants and contraceptives were included in the study. Levels of D-dimer and fibrinogen were measured for each patient prior to any intervention. Angiography or CT angiography was done in order to establish a definite diagnosis for each patient. Suitable analytical tests were performed to compare means.
  
  
  RESULTS
  Eighty-one patients were included in the study, of whom 41 had PTE and 40 did not. Mean values of D-dimer and fibrinogen were 3.97 ± 3.22 µg/ml and 560.6 ± 197.3 mg/dl, respectively. Significantly higher levels of D-dimer (4.65 ± 3.46 vs 2.25 ± 2.55 µg/ml, p = 0.006) and DDFR (0.913 ± 0.716 vs 483 ± 0.440 × 10-(3), p = 0.003) were seen in PTE patients than in those without PTE. Receiver operating characteristic (ROC) analysis showed a 70.3% sensitivity and 70.1% specificity with a D-dimer value of 2.43 µg/ml (AUC = 0.714, p = 0.002) as the best cut-off point; and a 70.3% sensitivity and 61.6% specificity with a DDFR value of 0.417 × 10-(3) (AUC = 0.710, p = 0.004) as the best cut-off point. In backward stepwise regression analysis, DDRF (OR = 0.72, p = 0.025), gender (OR = 0.76, p = 0.049) and white blood cell count (OR = 1.11, p = 0.373) were modelled (p = 0.029, R(2) = 0.577).
  
  
  CONCLUSIONS
  For diagnosis of PTE, DDFR can be considered to have almost the same importance as D-dimer level. Moreover, it was possible to rule out PTE with only a D-dimer cut-off value < 0.43 mg/dl, without the use of DDFR. However, these values cannot be used as a replacement for angiography or CT angiography.
authors.affiliation: Department of Cardiology, Rasoul-e-Akram Hospital, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Shokoufeh
authors.initials: S
authors.lastname: Hajsadeghi
authors.forename: Scott R
authors.initials: SR
authors.lastname: Kerman
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Khojandi
authors.forename: Helen
authors.initials: H
authors.lastname: Vaferi
authors.forename: Roza
authors.initials: R
authors.lastname: Ramezani
authors.forename: Negar M
authors.initials: NM
authors.lastname: Jourshari
authors.forename: Sayyed A J
authors.initials: SA
authors.lastname: Mousavi
authors.forename: Hamidezar
authors.initials: H
authors.lastname: Pouraliakbar
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D010343:Patient Admission; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000175:diagnosis*; D012680:Sensitivity and Specificity
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D