title: Incidence of deep venous thrombosis after subarachnoid hemorrhage.
abstract: OBJECTIVE
  The aim of this study was to determine the efficacy of venous ultrasonography in screening for deep venous thrombosis (DVT) after subarachnoid hemorrhage (SAH). A large cohort of patients who had suffered SAH was evaluated with the primary end points of ascertaining the incidence of asymptomatic DVT with venous Doppler ultrasonography screening and of identifying risk factors for the development of DVT and subsequent pulmonary embolism.
  
  
  METHODS
  Data from patients with aneurysmal SAH who had been admitted to the neurosurgical intensive care unit (ICU) between December 2002 and October 2006 were retrospectively evaluated. Patients who had undergone surgical or endovascular treatment of an aneurysm following SAH and survived > or = 15 days were included in the study.
  
  
  RESULTS
  The overall incidence of DVT among the entire study cohort was 18%. A subgroup analysis identified all patients, with or without symptoms for DVT, who had undergone venous Doppler ultrasonography screening. The incidence of asymptomatic DVT was 24%. Univariate analysis of all patients revealed a significant correlation between the risk of DVT and Hunt and Hess grade (r = 0.38, p < 0.0001), Fisher grade (r = 0.31, p < 0.0001), total hospital stay (r = 0.49, p < 0.0001), and number of days in the ICU (r = 0.48, p < 0.0001). Multivariate analysis demonstrated that the total hospital stay and number of days in the ICU were significant predictors of DVT in all patients (p < 0.0001 and p < 0.0002, respectively). In the subgroup of screened patients, Hunt and Hess grade, total hospital stay, and number of days in the ICU were significant predictors of DVT. Although screened patients were more likely to have DVT (chi(2) = 6.0976, p < 0.02), there was no significant difference in the incidence of DVT or pulmonary embolism between patients who did and those who did not undergo routine lower-extremity Doppler ultrasonography screening.
  
  
  CONCLUSIONS
  Routine compressive venous Doppler ultrasonography is an efficient, noninvasive means of identifying DVT as a screening modality in both symptomatic and asymptomatic patients following aneurysmal SAH. The ability to confirm or deny the presence of DVT in this patient population allows one to better identify the indications for chemoprophylaxis. Prophylaxis for venous thromboembolism in neurosurgical patients is common. Emerging literature and anecdotal experience have exposed risks of complications with prophylactic anticoagulation protocols. The identification of patients at high risk-for example, those with asymptomatic DVT-will allow physicians to better assess the role of prophylactic anticoagulation.
authors.affiliation: Departments of Neurological Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8057, St. Louis, Missouri 63110, USA. rayz@nsurg.wustl.edu
authors.forename: Wilson Z
authors.initials: WZ
authors.lastname: Ray
authors.forename: Russel G
authors.initials: RG
authors.lastname: Strom
authors.forename: Spiros L
authors.initials: SL
authors.lastname: Blackburn
authors.forename: William W
authors.initials: WW
authors.lastname: Ashley
authors.forename: Gregorio A
authors.initials: GA
authors.lastname: Sicard
authors.forename: Keith M
authors.initials: KM
authors.lastname: Rich
mesh_terms: D005260:Female; D006801:Humans; D007362:Intensive Care Units; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D018608:Ultrasonography, Doppler; D020246:Venous Thrombosis / Q000000981:diagnostic imaging* / Q000209:etiology*