title: Expanding Endovascular Therapy of Very Small Ruptured Aneurysms with the 1.5-mm Coil.
abstract: BACKGROUND
  Very small ruptured aneurysms (≤3 mm) demonstrate a significant risk for procedural rupture with endovascular therapy. Since 2007, 1.5-mm-diameter coils have been available (Micrus, Microvention, and ev3), allowing neurointerventionalists the opportunity to offer patients with very small aneurysms endovascular treatment. In this study, we review the clinical and angiographic outcome of patients with very small ruptured aneurysms treated with the 1.5-mm coil.
  
  
  METHODS
  This is a retrospective cohort study in which we examined consecutive ruptured very small aneurysms treated with coil embolization at a single institution. The longest linear aneurysm was recorded, even if the first coil was sized to a smaller transverse diameter. Very small aneurysms were defined as ≤3 mm. Descriptive results are presented.
  
  
  RESULTS
  From July 2007 to March 2015, 81 aneurysms were treated acutely with coils in 78 patients presenting with subarachnoid hemorrhage. There were 5 patients with 3-mm aneurysms, of which the transverse diameter was ≤2 mm in 3 patients. In all 5 patients, a balloon was placed for hemostatic prophylaxis in case of rupture, and a single 1.5-mm coil was inserted for aneurysm treatment without complication. Complete aneurysm occlusion was achieved in 1 patient, residual neck in 2, and residual aneurysm in 2 patients. Aneurysm recanalization was present in 2 patients with an anterior communicating artery aneurysm; a recoiling attempt was unsuccessful in 1 of these 2 patients due to inadvertent displacement and distal coil embolization, but subsequent surgical clipping was successful. Another patient was retreated by surgical clipping for a residual wide-neck carotid terminus aneurysm. One patient died of ventriculitis 3 weeks after presentation; all 4 other patients had an excellent outcome with no rebleed at follow-up (mean 21 months, range 1-62).
  
  
  CONCLUSIONS
  The advent of the 1.5-mm coil may be used in the endovascular treatment of patients with very small ruptured aneurysms, providing a temporary protection to the site of rupture in the acute phase. If necessary, bridging with elective clipping may provide definitive aneurysm treatment.
authors.affiliation: Department of Neurosurgery, Boston University School of Medicine, Boston Mass., USA ; Department of Radiology, Boston University School of Medicine, Boston Mass., USA.
authors.forename: Thanh N
authors.initials: TN
authors.lastname: Nguyen
authors.affiliation: Department of Neurology, Boston University School of Medicine, Boston Mass., USA ; Department of Radiology, Boston University School of Medicine, Boston Mass., USA.
authors.forename: Hesham
authors.initials: H
authors.lastname: Masoud
authors.affiliation: Department of Neurology, Desert Regional Medical Center, Palm Springs, Calif., USA ; Department of Neurosurgery, Desert Regional Medical Center, Palm Springs, Calif., USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Tarlov
authors.affiliation: Department of Neurosurgery, Boston University School of Medicine, Boston Mass., USA.
authors.forename: James
authors.initials: J
authors.lastname: Holsapple
authors.affiliation: Department of Neurosurgery, SUNY Upstate Medical University, Syracuse, N.Y., USA.
authors.forename: Lawrence S
authors.initials: LS
authors.lastname: Chin
authors.affiliation: Department of Radiology, Boston University School of Medicine, Boston Mass., USA.
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Norbash
keywords: Coil embolization; Endovascular therapy; Very small ruptured aneurysms