title: Aspirin withdrawal prior to invasive medical procedures: a strategy based on thromboembolic and bleeding risk stratification.
abstract: BACKGROUND
  The management of aspirin therapy before an invasive procedure poses a frequent clinical dilemma due to uncertainty regarding bleeding versus thromboembolic risks associated with continuation or withdrawal of the drug. There are no evidence-based data to refer to.
  
  
  OBJECTIVE
  To assess the opinions of internal medicine physicians regarding aspirin therapy prior to an invasive procedure.
  
  
  METHODS
  A questionnaire presenting nine hypothetical cases with different combinations of bleeding and thromboembolic risk was given to physicians in an internal medicine division during a personal interview. For each case the participants had to choose between withdrawal of aspirin prior to an invasive procedure, continuation of aspirin, or substitution of low molecular weight heparin for aspirin.
  
  
  RESULTS
  Sixty-one physicians participated in the survey. For a patient with low thromboembolic risk, 77% (95% confidence interval 65.3-86.3%), 95% (87.2-98.7%) and 97% (89.6-99.5%) of physicians elected to discontinue aspirin prior to a low, intermediate or high bleeding risk procedure, respectively. For intermediate risk patients, 23% (95% CI 13.7-34.7%), 59% (46.4-70.8%) and 74% (61.7-83.6%) would discontinue aspirin prior to a low, intermediate or high risk procedure, and 5% (95% CI 1.3-12.8%), 23% (13.7-34.7%) and 18% (9.9-29.2%) would substitute LMWH for aspirin. For a patient with high thromboembolic risk, 1.6% (95% CI 0.08-7.8%), 11.5% (5.2-21.4%) and 18% (9.9-29.2%) recommended discontinuing aspirin prior to a low, intermediate or high risk procedure, respectively. In these situations, 18% (95% CI 9.9-29.2%), 53% (40.0-64.7%) and 57% (44.8-69.3%), respectively, would substitute LMWH for aspirin.
  
  
  CONCLUSIONS
  The results of the current investigation may help practicing physicians to decide whether to discontinue aspirin therapy prior to invasive procedures. The possible use of LMWH to replace aspirin as suggested here should be further evaluated in a controlled clinical study.
authors.affiliation: Department of Internal Medicine B, Hadassah-Hebrew University Medical Center, Jerusalem, Israel. auryan@md.huji.ac.il
authors.forename: Auryan
authors.initials: A
authors.lastname: Szalat
authors.forename: Gilli
authors.initials: G
authors.lastname: Erez
authors.forename: Eran
authors.initials: E
authors.lastname: Leitersdorf
mesh_terms: D001241:Aspirin / Q000008:administration & dosage* / Q000009:adverse effects; D001291:Attitude of Health Personnel; D016063:Blood Loss, Surgical; D004334:Drug Administration Schedule; D005343:Fibrinolytic Agents / Q000008:administration & dosage* / Q000009:adverse effects; D019538:Health Care Surveys; D006495:Heparin, Low-Molecular-Weight / Q000008:administration & dosage*; D006801:Humans; D007388:Internal Medicine / Q000379:methods / Q000706:statistics & numerical data*; D007407:Interviews as Topic; D011300:Preoperative Care / Q000379:methods*; D018570:Risk Assessment; D012307:Risk Factors; D013514:Surgical Procedures, Operative / Q000145:classification; D013923:Thromboembolism / Q000517:prevention & control*; D013997:Time Factors
chemical_list: D005343:Fibrinolytic Agents; D006495:Heparin, Low-Molecular-Weight; D001241:Aspirin