title: The Utility of Ankle-Brachial Index as a Predictor of Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage.
abstract: OBJECTIVE
  Delayed cerebral ischemia (DCI) can cause significant morbidity and mortality in patients suffering from aneurysmal subarachnoid hemorrhage (SAH). Because arterial stiffness has been correlated with vascular risk factors, we evaluated whether the ankle-brachial index (ABI), the ratio of the ankle and brachial systolic blood pressures, can predict DCI.
  
  
  METHODS
  In a prospective cohort study, we measured the ABIs of 24 patients with aneurysmal SAH during the weeks after SAH. Angiographic vasospasm was evaluated via diagnostic cerebral angiograms. Transcranial Doppler (TCD) was used to assess associations among ABI, DCI, and angiographic vasospasm.
  
  
  RESULTS
  Patients were evaluated on the basis of the presence or absence of DCI (days 3-14 after SAH). Demographic and history factors were similar between the DCI and non-DCI groups. Patients in the DCI group had a greater modified Fisher grade (P = 0.029) and were more likely to have been treated via clipping (P = 0.032) and to demonstrate angiographic vasospasm (P = 0.009). Mean TCD values in the 2 groups were significantly different after day 5 in varied arterial distributions (P < 0.05). ABI values in the DCI group were significantly lower on posthemorrhage days 2-13 and when averaged over the 2-week study period (P < 0.05). An average ABI >1.045 on days 2-7 was 85% sensitive and 82% specific for predicting absence of DCI.
  
  
  CONCLUSIONS
  In this small single-center study, lower ABI values were strongly associated with SAH-induced DCI, which may provide a tool for managing DCI in aneurysmal SAH.
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Guan
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Karsy
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Brock
authors.affiliation: Department of Neurosurgery, Clinical Neurosciences Center, University of Utah, Salt Lake City, Utah, USA. Electronic address: neuropub@hsc.utah.edu.
authors.forename: William T
authors.initials: WT
authors.lastname: Couldwell
mesh_terms: D015901:Angiography, Digital Subtraction; D055109:Ankle Brachial Index; D001921:Brain / Q000000981:diagnostic imaging / Q000601:surgery; D002545:Brain Ischemia / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology; D002533:Cerebral Angiography; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012720:Severity of Illness Index; D013345:Subarachnoid Hemorrhage / Q000150:complications* / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D014057:Tomography, X-Ray Computed; D017585:Ultrasonography, Doppler, Transcranial; D020301:Vasospasm, Intracranial / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery
keywords: Ankle-brachial index; Arterial stiffness; Cerebral aneurysm; Delayed cerebral ischemia; Subarachnoid hemorrhage; Vasospasm