title: D-dimer plasma level: a reliable marker for venous thromboembolism after elective craniotomy.
abstract: OBJECTIVE
  The incidence of deep venous thrombosis (DVT) after craniotomy is reported to be as high as 50%. In outpatients, D-dimer levels of more than 0.5 mg/L indicate venous thromboembolism (VTE, which subsumes DVT and pulmonary embolism [PE]) with a sensitivity of 99.4% and a specificity of 38.2%. However, D-dimer levels are believed to be unreliable in postoperative patients. The authors undertook the present study to test the hypothesis that D-dimer levels would be systematically raised in a postoperative population and to define a feasible threshold for identification of VTE.
  
  
  METHODS
  Doppler ultrasonography of the lower extremity was performed pre- and postoperatively to evaluate for DVT in 101 patients who underwent elective craniotomy. D-dimer levels were assessed preoperatively and on the 3rd, 7th, and 10th days after surgery. Statistical analysis was carried out to define a feasible threshold for D-dimer levels.
  
  
  RESULTS
  D-dimer plasma levels were found to be systematically raised postoperatively, and they differed between patients with and without VTE in a highly significant way. On the 3rd day after surgery, D-dimer levels of more than 2 mg/L indicated VTE with a sensitivity of 95.3% and a specificity of 74.1%, allowing for the definition of a feasible threshold. D-dimer levels of more than 4 mg/L were observed in all patients who had PE during the postoperative period (n = 9). Ventilation time and duration of surgery were identified as highly significant risk factors for the development of VTE.
  
  
  CONCLUSIONS
  Using a threshold of 2 mg/L, D-dimer levels will indicate VTE with a high degree of sensitivity and specificity in patients who have undergone craniotomy. Pulmonary embolism seems to be indicated by even higher D-dimer levels. Given that the development of D-dimer plasma levels in the postoperative period follows a principle that can be predicted and that deviations from it indicate VTE, this principle might be applicable to other types of surgery.
authors.affiliation: Departments of Neurosurgery and.
authors.forename: Julian
authors.initials: J
authors.lastname: Prell
authors.forename: Jens
authors.initials: J
authors.lastname: Rachinger
authors.forename: Robert
authors.initials: R
authors.lastname: Smaczny
authors.forename: Bettina-Maria
authors.initials: BM
authors.lastname: Taute
authors.forename: Stefan
authors.initials: S
authors.lastname: Rampp
authors.forename: Joerg
authors.initials: J
authors.lastname: Illert
authors.forename: Gershom
authors.initials: G
authors.lastname: Koman
authors.forename: Christian
authors.initials: C
authors.lastname: Marquart
authors.forename: Alexandra
authors.initials: A
authors.lastname: Rachinger
authors.forename: Sebastian
authors.initials: S
authors.lastname: Simmermacher
authors.forename: Alex
authors.initials: A
authors.lastname: Alfieri
authors.forename: Christian
authors.initials: C
authors.lastname: Scheller
authors.forename: Christian
authors.initials: C
authors.lastname: Strauss
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D003399:Craniotomy / Q000009:adverse effects; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products; D006801:Humans; D035002:Lower Extremity / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood*; D011184:Postoperative Period; D011237:Predictive Value of Tests; D011446:Prospective Studies; D014463:Ultrasonography; D054556:Venous Thromboembolism / Q000097:blood* / Q000000981:diagnostic imaging / Q000209:etiology; D055815:Young Adult
chemical_list: D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D