title: NICE thromboprophylaxis guidelines are not associated with increased pericardial effusion after surgery of the proximal thoracic aorta.
abstract: BACKGROUND
  In 2010 the National Institute for Health and Clinical Excellence (NICE) released guidelines on venous thromboembolism. Strategy focused on risk assessment, antiembolic stockings, sequential compression devices, subcutaneous high dose enoxaparin (40 mg), early mobilisation and hydration. The 40 mg enoxaparin dose over the previous 20 mg regimen was worrisome, and its effect on pericardial effusion rates and mortality in proximal aortic surgery was investigated.
  
  
  METHODS
  Proximal aortic reconstructions performed between December 2008 and April 2011 were identified from prospectively collected data in a tertiary centre database. Retrospective analysis of patient notes was performed. Proximal aortic surgery patients were categorised as low dose (20 mg) enoxaparin and high dose (40 mg) enoxaparin, and compared for confounding variables. In-hospital, early and one-year readmission rates for pericardial effusion were ascertained from echocardiography reports. The primary outcome was total pericardial effusion rate. Secondary outcomes consisted of 30-day and 1-year mortality.
  
  
  RESULTS
  A total of 198 patients underwent proximal thoracic aortic surgery. Nine patients were excluded due to early postoperative death (n=5) and missing patient records (n=4). This left 189 cases for analysis. There were 93 patients in the low dose group and 96 in the high dose group. Groups were comparable for age, cardiopulmonary bypass time, aortic cross-clamp time, postoperative warfarin and antiplatelet agents. Pericardial effusion rates up to one year were comparable (low dose 19% vs high dose 21%). Thirty-day mortality was lower in the low dose group (0 vs 3 deaths). There were four deaths up to one year but these were not attributable to increased enoxaparin.
  
  
  CONCLUSIONS
  Increased perioperative thromboprophylaxis dosage does not increase pericardial effusion rates or mortality in proximal aortic surgery.
authors.affiliation: University Hospitals Bristol NHS Foundation Trust, Bristol Heart Institute, Bristol Royal Infirmary, Upper Maudlin Street, Bristol BS2 8HW, UK. ishtiaqrahman@nhs.net.
authors.forename: I A
authors.initials: IA
authors.lastname: Rahman
authors.forename: A
authors.initials: A
authors.lastname: Hussain
authors.forename: A
authors.initials: A
authors.lastname: Davies
authors.forename: A J
authors.initials: AJ
authors.lastname: Bryan
mesh_terms: D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects*; D001013:Aorta, Thoracic / Q000601:surgery; D001018:Aortic Diseases / Q000601:surgery*; D001026:Coronary Artery Bypass / Q000706:statistics & numerical data; D017984:Enoxaparin / Q000008:administration & dosage / Q000009:adverse effects*; D006801:Humans; D008875:Middle Aged; D061646:Operative Time; D010359:Patient Readmission / Q000706:statistics & numerical data; D010490:Pericardial Effusion / Q000139:chemically induced*; D011183:Postoperative Complications / Q000517:prevention & control*; D017410:Practice Guidelines as Topic; D011446:Prospective Studies; D053828:Stockings, Compression; D016896:Treatment Outcome; D054556:Venous Thromboembolism / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin
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