title: A Phase I proof-of-concept and safety trial of sildenafil to treat cerebral vasospasm following subarachnoid hemorrhage.
abstract: OBJECTIVE
  Studies show that phosphodiesterase-V (PDE-V) inhibition reduces cerebral vasospasm (CVS) and improves outcomes after experimental subarachnoid hemorrhage (SAH). This study was performed to investigate the safety and effect of sildenafil (an FDA-approved PDE-V inhibitor) on angiographic CVS in SAH patients.
  
  
  METHODS
  A2-phase, prospective, nonrandomized, human trial was implemented. Subarachnoid hemorrhage patients underwent angiography on Day 7 to assess for CVS. Those with CVS were given 10 mg of intravenous sildenafil in the first phase of the study and 30 mg in the second phase. In both, angiography was repeated 30 minutes after infusion. Safety was assessed by monitoring neurological examination findings and vital signs and for the development of adverse reactions. For angiographic assessment, in a blinded fashion, pre- and post-sildenafil images were graded as "improvement" or "no improvement" in CVS. Unblinded measurements were made between pre- and post-sildenafil angiograms.
  
  
  RESULTS
  Twelve patients received sildenafil; 5 patients received 10 mg and 7 received 30 mg. There were no adverse reactions. There was no adverse effect on heart rate or intracranial pressure. Sildenafil resulted in a transient decline in mean arterial pressure, an average of 17% with a return to baseline in an average of 18 minutes. Eight patients (67%) were found to have a positive angiographic response to sildenafil, 3 (60%) in the low-dose group and 5 (71%) in the high-dose group. The largest degree of vessel dilation was an average of 0.8 mm (range 0-2.1 mm). This corresponded to an average percentage increase in vessel diameter of 62% (range 0%-200%).
  
  
  CONCLUSIONS
  The results from this Phase I safety and proof-of-concept trial assessing the use of intravenous sildenafil in patients with CVS show that sildenafil is safe and well tolerated in the setting of SAH. Furthermore, the angiographic data suggest that sildenafil has a positive impact on human CVS.
authors: Departments of 1 Neurological Surgery.|Radiology, Washington University School of Medicine, Saint Louis, Missouri.
authors: Chad W
authors: CW
authors: Washington
authors: Departments of 1 Neurological Surgery.|Radiology, Washington University School of Medicine, Saint Louis, Missouri.
authors: Colin P
authors: CP
authors: Derdeyn
authors: Neurology, and.
authors: Rajat
authors: R
authors: Dhar
authors: Departments of 1 Neurological Surgery.
authors: Eric J
authors: EJ
authors: Arias
authors: Departments of 1 Neurological Surgery.
authors: Michael R
authors: MR
authors: Chicoine
authors: Departments of 1 Neurological Surgery.|Radiology, Washington University School of Medicine, Saint Louis, Missouri.
authors: DeWitte T
authors: DT
authors: Cross
authors: Departments of 1 Neurological Surgery.
authors: Ralph G
authors: RG
authors: Dacey
authors: Departments of 1 Neurological Surgery.
authors: Byung Hee
authors: BH
authors: Han
authors: Departments of 1 Neurological Surgery.|Radiology, Washington University School of Medicine, Saint Louis, Missouri.
authors: Christopher J
authors: CJ
authors: Moran
authors: Departments of 1 Neurological Surgery.|Radiology, Washington University School of Medicine, Saint Louis, Missouri.
authors: Keith M
authors: KM
authors: Rich
authors: Departments of 1 Neurological Surgery.
authors: Ananth K
authors: AK
authors: Vellimana
authors: Departments of 1 Neurological Surgery.|Neurology, and.
authors: Gregory J
authors: GJ
authors: Zipfel
mesh_terms: D061605:Administration, Intravenous; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D062186:Arterial Pressure / Q000187:drug effects; D002533:Cerebral Angiography; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D000068677:Sildenafil Citrate / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D020301:Vasospasm, Intracranial / Q000188:drug therapy* / Q000209:etiology*
chemical_list: D014665:Vasodilator Agents; D000068677:Sildenafil Citrate
keywords: CVS = cerebrovascular vasospasm; DCI = delayed cerebral ischemia; DSA = digital subtraction angiography; DSMB = Data Safety Monitoring Board; ICA = internal carotid artery; ICP = intracranial pressure; MAP = mean arterial pressure; MCA = middle cerebral artery; NNICU = Neurology/Neurosurgery ICU; NO = nitric oxide; PDE-V = phosphodiesterase-V; SAH = subarachnoid hemorrhage; aneurysm; cGMP = cyclic guanosine monophosphate; cerebral vasospasm; delayed cerebral ischemia; eNOS = endothelial nitric oxide synthase; subarachnoid hemorrhage; vascular disorders