Corneal Nerve Loss in Patients with Acute Ischemic Stroke: A Surrogate Marker for Poor Pial Collaterals

Background: In patients with ischemic stroke, pial collaterals play a key role in limiting neurological disability by maintaining blood flow to ischemic penumbra. We hypothesized that patient with poor pial collateral status will have greater corneal nerve and endothelial cell abnormalities. Method: 35 patients with acute ischemic stroke secondary to middle cerebral artery occlusion with poor (n=12) and moderate/good (n=23) pial collaterals and 35 healthy controls underwent corneal confocal microscopy and quantification of corneal nerve and endothelial cell morphology. Results: : In patients with MCA stroke, corneal nerve fibre length (CNFL) (P=0.000), density (CNFD) (P=0.025) and branch density (CNBD) (P=0.002) were lower compared to controls. Age, BMI, cholesterol, triglycerides, HDL, LDL, systolic blood pressure, NIHSS and endothelial cell parameters did not differ but mRS was higher (p=0.023) and CNFL (p=0.026) and CNBD (p=0.044) were lower in patients with poor compared to moderate-good collaterals. CNFL and CNBD distinguished subjects with poor from good pial collaterals with an AUC of 72% (95% CI: 53-92%) and 71% (95% CI: 53-90%), respectively. Conclusion: Corneal nerve loss is greater in patients with poor compared to good pial collaterals and may act as a surrogate marker for pial collateral status in patients with ischemic stroke.