Impact of Collateral Status on Neuroprotective Effect of Cyclosporine A in Acute Ischemic Stroke

Background: Neuroprotection for acute ischemic stroke remains an elusive goal. Intracranial collaterals may favor neuroprotective drugs delivery at the acute stage of ischemic stroke. A recent phase 2 study showed that cyclosporine A (CsA) reduced ischemic damage in patients with a proximal occlusion who experienced effective recanalization. Collateral flow may improve this benefit. Materials & Methods: Collateral supply was assessed using dynamic susceptibility contrast MRI in 47 patients among the 110 patients from the original study and were graded in two groups: good collaterals and poor collaterals. Patients with good collaterals had significantly smaller initial infarct in both CsA group (p = 0.003) and controls (p = 0.016). Similarly, the final lesion volume was significantly lower in patients with good collaterals in both groups. Results: In patients with either good or poor collaterals CsA showed no additional benefit on ischemic lesion progression and final infarct size at day 30. Conclusion: We failed to demonstrate any significant additional benefit of CsA in patients with good collateral circulation.