Aging and ischemic stroke

795,000 strokes occurring annually in the United States, 87% are classified as ischemic strokes 1.Aging is the most robust non-modifiable risk factor for incident stroke, which doubles every 10 years after age 55 years.Approximately three-quarters of all strokes occur in persons aged ≥65 years.As the number of people aged ≥ 65 years is projected to grow, the number of incident strokes in older adults is expected to rise, presenting major challenges for clinicians and policy makers in the foreseeable future.Aging and cerebral vasculature.The complex network of the adult brain vasculature measures approximately 370 miles, receives about 20% of total cardiac output, and exchanges 20% of total blood glucose and oxygen.With aging, both cerebral microand macro-circulations undergo structural and functional alterations.Age-related microcirculatory changes are presumably mediated by endothelial dys-function and impaired cerebral autoregulation and neurovascular coupling.Whereas endothelial dysfunc-tion promotes neuro-inflammation, impaired cerebral autoregulation may lead to microvascular injury, and impaired neurovascular coupling fosters a decline in cortical function, all potential targets for future therapeutic interventions.Aging, in otherwise healthy individuals, is associated with numerous noticeable changes in human intracranial and extracranial cerebral arteries that predict the risk of future stroke.Aging and silent cerebrovascular disease.Silent cerebrovascular disease represents structural abnormalities, presumed vascular etiology, on neuroimaging not supported by clinically recognized stroke symptoms.The prevalence of silent cerebrovascular disease increases with advancing age and is recognizable as the following parenchymal lesions: 1) Silent infarcts (silent strokes), prevalence 6% and 28%, exceeds symptomatic stroke by a ratio of 10:1, 2) white matter hyperintensity or hypodensity on neuroimaging represent microvascular disease occurring in 20% to 94% older adults, and 3) cerebral microbleeds indicate silent intracerebral hemorrhages in 38% of general population aged >80 years.These conditions are age dependent and forecast increased risk of future symptomatic strokes (Figure 1).Aging and stroke risk factors.A worldwide population-based study identified 10 risk factors that collectively account for 88% of the risk of stroke in all Aging and ischemic stroke