NAION Shown to Increase Risk of Ischemic Stroke

Carotid artery stenosis remains a major risk factor for large-vessel stroke, and development of this may accelerate carotid plaque buildup, leading to future strokes. Photo: Cleveland Clinic. Click image to enlarge. Hypoperfusion to the optic nerve head—the presumed culprit in nonarteritic anterior ischemic optic neuropathy (NAION)—and thromboembolic ischemic strokes are different processes that share similar risk factors, including hypertension, diabetes and cardiovascular disorders. Recently, researchers investigated their relationship using a cohort database from a healthcare network in Israel. The investigators were looking for occurrences of ischemic stroke in those with NAION to assess the link between the condition and carotid artery stenosis (CAS) as an ischemic stroke risk factor.From a database of over 1,200,000 insured individuals, 605 NAION patients without prior ischemic stroke history were identified; these patients were then matched with a 10-fold larger comparison group by age, sex and cardiovascular risk factors. Patients with NAION were found to have higher incidence of large- (18.7% vs. 14.7%) and small-vessel (4.8% vs. 3.1%) ischemic stroke than the comparison group. Both during the study and follow-up, NAION patients had elevated CAS prevalence. Multivariate analysis revealed patients with NAION had a 1.5 hazard ratio of developing large-vessel ischemic stroke and a 1.56 value for small-vessel. Finally, cumulative probability of ischemic stroke in NAION patients without risk factors was higher than for the comparison group without risk factors.In their paper on the work for Journal of Neuro-ophthalmology, the authors explain two potential pathologies linking this association, one to do with large and another will small cerebral vessels. In large-vessel disease, the findings indicate CAS was more common in NAION patients at study entry and as newly identified cases post-NAION. As the researchers elucidate in their paper, “this suggests a triadic link among NAION, CAS and large-vessel stroke,” elaborating that one theory surrounding this is CAS lowering ocular blood perfusion pressure, thus leading to vasospastic occlusion of short posterior ciliary arteries. The data designated a 13.7% CAS diagnosis incidence in NAION patients, which reflects previous research finding >50% stenosis in 11% of cases.The other mechanism is related to small-vessel pathology due to chronic degenerative changes. Both NAION and lacunar strokes involve arterioles; in stroke, these are cerebral arterioles and in NAION they are short posterior ciliary artery branches. One prior investigation found small-vessel disease more common in those with NAION, with MRI showing chronic small-vessel disease changes linked to hypoperfusion and long-term brain damage.The authors of the study contend that “there is a need to consider specific management for patients with NAION diagnosed with carotid artery stenosis because of the potential for a triadic relationship among the three conditions.”Click here for the journal source. Shamesh R, Rosenblatt HN, Huna-Baron R, Klein A, Zloto O. The risk of ischemic stroke in patients with nonarteritic anterior ischemic optic neuropathy: a bib data study. J Neuroophthalmol. 2025;00:1-7.