title: Venous thromboembolism prophylaxis in patients undergoing cranial neurosurgery: a systematic review and meta-analysis.
abstract: BACKGROUND
  Randomized clinical trials (RCTs) have usually supported using heparin prophylaxis against venous thromboembolism (VTE) in patients undergoing cranial neurosurgery. The tradeoff between benefit and bleeding risk, however, has not been adequately characterized.
  
  
  OBJECTIVE
  To conduct a systematic review and meta-analysis assessing the extent to which low-dose unfractionated heparin (LDUH) or low-molecular-weight heparin (LMWH) prophylaxis reduces the rate of VTE and increases the rate of intracerebral hemorrhage (ICH) and other bleeding in patients undergoing elective cranial neurosurgery.
  
  
  METHODS
  We selected RCTs that evaluated LDUH or LMWH prophylaxis of VTE in patients undergoing elective cranial neurosurgery. A meta-analysis assessing heparins vs no heparin (either with or without mechanical methods) was performed.
  
  
  RESULTS
  Eight RCTs were identified. Six RCTs involving 1170 patients evaluated LDUH or LMWH vs a control group. Five of 6 trials found a significant reduction in the risk of symptomatic and asymptomatic VTE with heparin prophylaxis. The pooled risk ratio was 0.58 (95% confidence interval, 0.45-0.75). ICH was more common in those receiving heparin, but not statistically significantly. For every 1000 patients who receive heparin prophylaxis, 91 VTE events will be prevented (approximately 35 of which are proximal deep vein thrombosis or pulmonary embolism and 9 to 18 of which are symptomatic), whereas 7 ICHs and 28 more minor bleeds will occur.
  
  
  CONCLUSIONS
  Heparin prophylaxis for patients undergoing elective cranial neurosurgery reduces the risk of VTE but may also increase bleeding risks with a ratio of serious or symptomatic VTE relative to serious bleeding that is only slightly favorable.
authors.affiliation: Department of Clinical Neurosciences, University of Calgary, Foothills Hospital, Calgary, Alberta, Canada. mhamilto@ucalgary.ca
authors.forename: Mark G
authors.initials: MG
authors.lastname: Hamilton
authors.forename: Wendy H
authors.initials: WH
authors.lastname: Yee
authors.forename: Russell D
authors.initials: RD
authors.lastname: Hull
authors.forename: William A
authors.initials: WA
authors.lastname: Ghali
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage; D001927:Brain Diseases / Q000453:epidemiology / Q000601:surgery; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D015897:Comorbidity; D006470:Hemorrhage / Q000453:epidemiology*; D006493:Heparin / Q000627:therapeutic use*; D006801:Humans; D019635:Neurosurgical Procedures / Q000706:statistics & numerical data*; D011183:Postoperative Complications / Q000453:epidemiology* / Q000517:prevention & control; D011292:Premedication / Q000706:statistics & numerical data*; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D054556:Venous Thromboembolism / Q000453:epidemiology* / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D006493:Heparin