Single blood injection into the ventral cisterna magna through a microcatheter for the production of delayed cerebral vasospasm: experimental study in dogs.

Background And Purpose: We developed an experimental canine subarachnoid hemorrhage (SAH) model in which one-time blood injection by means of a microcatheter into the ventral cisterna magna (CM) is performed without direct CM puncture. We assessed the severity and duration of the vasospasm produced in this model.

Methods: Fresh autologous blood (0.25 or 0.5 ml/kg) or saline (0.5 ml/kg) was injected into the ventral CM of dogs through a microcatheter inserted at the lumbar region. Serial angiograms were obtained on days 3, 7, 10, and 14, and chronologic changes in the mean diameter of the basilar artery (BA) were recorded. The BA was examined histologically on day 7 after injection.

Results: A remarkable amount of clot was present in front of the brain stem at 24 hours after SAH induction. The clot was smaller in the 0.25 ml/kg SAH than in the 0.5 ml/kg SAH group. On day 3, narrowing of the BA was apparent in both SAH groups compared with the control (P <.05). The BA gradually returned to nearly normal on day 14 in the 0.25 ml/kg SAH group. Arterial narrowing was more severe and persistent in the 0.5 ml/kg SAH than in the 0.25 ml/kg SAH group (P <.05). Histologic examination of the BA on the 7th postinjection day confirmed narrowing of the lumen, indicative of arterial spasm, in both SAH groups.

Conclusion: Our method of SAH induction by means of a single injection of blood directly into the ventral CM through a microcatheter induced severe, prolonged spasms in the canine BA. Because our model facilitates the induction of different-sized clots, we could control of the severity and duration of the induced vasospasms.