title: Predictors and outcomes of suspected heparin-induced thrombocytopenia in subarachnoid hemorrhage patients.
abstract: BACKGROUND
  Heparin-induced thrombocytopenia (HIT) is a dreaded complication of heparin-related products and correlates with a worse outcome in aneurysmal subarachnoid hemorrhage (SAH) patients.
  
  
  OBJECTIVE
  To study the risk factors and outcomes of SAH patients suspected of having HIT, confirmed as present or absent by the platelet factor 4 (PF4) antibody test.
  
  
  METHODS
  All patients with presumed aneurysmal, nontraumatic SAH and having undergone a PF4 test were identified through our research patient database. Charts, laboratory values and images were analyzed retrospectively.
  
  
  RESULTS
  We identified 166 patients with SAH who were tested for HIT; 42 patients (25%) had a positive antibody test. There was no difference in platelet profiles or mean platelet nadirs of HIT+ and HIT- patients (147 ± 93 vs. 153 ± 86 ×10(9)/l, respectively). Univariate analysis identified gender, magnesium prophylaxis, Fisher group 3, clipping versus coiling, presence of angiographic vasospasm, number of vasospasm treatments, and day of HIT testing as potential risk factors associated with HIT. A multivariate analysis indicated that female gender (OR 8.2, 95% CI 2.0-33.2), greater number of vasospasm treatments (OR 1.5, 95% CI 1.2-2.0), later day of HIT testing (OR 1.2, 95% CI 1.1-1.3), and clipping (OR 5.0, 95% CI 1.42-10.0) were independently associated with HIT positivity. HIT+ patients showed more infarcts on CT, longer ICU and hospital stays and worse modified Rankin Scale scores on discharge.
  
  
  CONCLUSIONS
  The presence of HIT in SAH has adverse consequences and is more likely in female patients who have undergone aneurysm clipping and require multiple endovascular vasospasm treatments.
authors.affiliation: Department of Neurology, Harvard Medical School, Boston, Mass., USA ; Department of Radiology, Harvard Medical School, Boston, Mass., USA.
authors.forename: Brijesh P
authors.initials: BP
authors.lastname: Mehta
authors.affiliation: Department of Neurology, Harvard Medical School, Boston, Mass., USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Sims
authors.affiliation: Department of Radiology, Harvard Medical School, Boston, Mass., USA.
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Baccin
authors.affiliation: Department of Neurology, Harvard Medical School, Boston, Mass., USA ; Department of Radiology, Harvard Medical School, Boston, Mass., USA.
authors.forename: Thabele M
authors.initials: TM
authors.lastname: Leslie-Mazwi
authors.affiliation: Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Mass., USA.
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Ogilvy
authors.affiliation: Department of Neurology, Emory University School of Medicine, Atlanta, Ga., USA.
authors.forename: Raul G
authors.initials: RG
authors.lastname: Nogueira
keywords: Delayed ischemic neurologic deficit; Gender; Heparin-induced thrombocytopenia; Subarachnoid hemorrhage; Vasospasm