Lacunar Stroke

Stroke is the second most common cause of death worldwide and the leading cause of disability in the United States. Ischemic strokes are the most common, comprising about 62% of strokes worldwide in 2019. The remainder are hemorrhagic. Lacunar strokes account for about 25% of all ischemic strokes. By definition, these strokes are small and located in noncortical areas. These infarcts are classically defined to be smaller than 15 mm in diameter. However, more recent studies have found that the size correlates more with the order of the penetrating branches from the parent artery. The diameter may vary from 2 to 3 mm up to 15 to 20 mm.

The name lacunar, derived from the Latin lacune, meaning pond or pit, refers to the final pathology of small subcortical spaces in the grey or white matter filled with cerebral spinal fluid. The occlusion of small, deep penetrating branches of the cerebral vessels from the circle of Willis, including branches from the middle cerebral artery, anterior cerebral artery, posterior cerebral artery, or basilar artery, causes lacunar infarctions. These penetrating arteries are end arteries without any collaterals. Many lacunar strokes remain asymptomatic due to the involvement of small vessels causing small-sized infarcts. Additionally, 20% to 50% of the elderly population were found to have asymptomatic lacunar strokes on imaging. However, accumulating multiple small lacunar infarcts can lead to significant physical and cognitive disabilities. Despite not having the devastating effects of large vessel strokes, lacunar strokes are not benign. About 25% will die from the lacunar stroke or complications, 20% will have a recurrent cerebrovascular event, and 30% will be functionally impaired at a 5-year follow-up. Certain clinical syndromes are characteristic of lacunar stroke symptoms, but the correlation is not absolute. For example, large vessel cortical strokes can present with the same clinical picture as lacunar strokes, and lacunar strokes can be caused by embolic sources or disease in large cerebral vessels causing occlusion of the small perforating artery, rather than the typical lipohyalinosis or thrombosis associated with lacunar strokes.