title: Clinical relevance of isolated prolongation of the activated partial thromboplastin time in a cohort of adults undergoing surgical procedures.
abstract: BACKGROUND
  Coagulation screening prior to surgery is performed routinely worldwide to identify patients at risk of bleeding during the procedure. Evidence from medical and surgical literature suggests that the activated partial thromboplastin time (aPTT) alone is suitable for predicting individual bleeding risk during surgery and it is current practice in our hospital to measure this parameter.
  
  
  METHODS
  We retrospectively reviewed aPTT ratio results in 8,069 consecutive adult subjects undergoing elective surgery from January 1 to December 31, 2014 to confirm the validity of this approach.
  
  
  RESULTS
  In 7,606 patients (94.2%) the aPTT ratio was within the normal range while it was abnormal in 463 (5.8%). Out of these 463, 223 aPTT ratios were between 1.2 and 1.3 and we considered these results not worthy enough of further investigations. In 240 patients the aPTT ratio was higher than 1.3; in the vast majority of these cases (201/240; 83%) this abnormality was associated with oral anticoagulant treatment. Seventeen of the other 39 cases underwent detailed investigations which revealed lupus anticoagulant (n=7), decompensated chronic liver disease (n=4), factor XII deficiency (n=3), mild combined reduction of FXI and FXII (n=1) and mild haemophilia A (n=2). The other 22 patients underwent successful surgery without further investigation.
  
  
  CONCLUSIONS
  Our results from a pre-surgical setting seem to confirm the low prevalence of coagulation defects in the general population. Increased aPTT ratios were mainly attributable to oral anticoagulant therapy, with a few cases caused by mild, clinically irrelevant clotting factor deficiencies. A carefully taken personal history, including medications (i.e. oral anticoagulants) and/or previous bleeding symptoms seem more useful than coagulation screening tests to predict the risk of bleeding.
authors.affiliation: Transfusion Service, Haemophilia Centre and Haematology, Laboratory Analysis, Castelfranco Veneto Hospital, Castelfranco Veneto, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Tagariello
authors.affiliation: Transfusion Service, Haemophilia Centre and Haematology, Laboratory Analysis, Castelfranco Veneto Hospital, Castelfranco Veneto, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Radossi
authors.affiliation: Transfusion Service, Haemophilia Centre and Haematology, Laboratory Analysis, Castelfranco Veneto Hospital, Castelfranco Veneto, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Salviato
authors.affiliation: Laboratory Analysis, Castelfranco Veneto Hospital, Castelfranco Veneto, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: Zardo
authors.affiliation: Laboratory Analysis, Castelfranco Veneto Hospital, Castelfranco Veneto, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: De Valentin
authors.affiliation: Transfusion Service, Haemophilia Centre and Haematology, Laboratory Analysis, Castelfranco Veneto Hospital, Castelfranco Veneto, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Basso
authors.affiliation: Centre for Bleeding Disorders, Careggi University Hospital, Florence, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Castaman
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use; D016063:Blood Loss, Surgical / Q000517:prevention & control; D015331:Cohort Studies; D017558:Elective Surgical Procedures / Q000009:adverse effects*; D005260:Female; D006470:Hemorrhage / Q000097:blood / Q000209:etiology*; D006801:Humans; D008297:Male; D010314:Partial Thromboplastin Time; D012189:Retrospective Studies; D012306:Risk
chemical_list: D000925:Anticoagulants