Letter by Drinka Regarding Article, “Low-Density Lipoprotein Cholesterol Concentrations and Death Due to Intraparenchymal Hemorrhage: The Ibaraki Prefectural Health Study”
To the Editor:
Noda et al1 reported that reduced low-density lipoprotein levels were associated with an elevated risk of death due to intraparenchymal hemorrhage. Lesions of the penetrating branches of cerebral arteries cause lacunar infarcts and hemorrhagic stroke. Fisher examined serial sections from the parent artery through the lacunae.2,3 He found atheroma and thrombosis in some and obstructing lipohyalin degeneration in others. Atheroma involved arteries 400 to 900 μ in diameter, whereas lipohyalin degeneration involved arteries <200 μ in diameter. Lipohyalin degeneration produced a thinned wall composed of connective tissue shreds. In some patients this resulted in false aneurysm resembling the Charcot-Bouchard aneurysms of brain hemorrhage. The location of lesions in the penetrating arteries (ie, proximal atheromas versus distal lipohyalin degeneration) may explain an inverse relationship between cholesterol and hemorrhagic stroke. Perhaps atheromatous proximal flow restriction facilitated by elevated low-density lipoproteins protects the distal artery from hypertension, lipohyalin degeneration, false aneurysm formation, and hemorrhagic rupture.
Noda H, Iso H, Irie F, Sairenchi T, Ohtaka E, Doi M, Izumi Y, Ohta H. Low-density lipoprotein cholesterol concentrations and death due to intraparenchymal hemorrhage: the Ibaraki Prefectural Health Study. Circulation. 2009; 119: 2136–2145.
Fisher CM. Lacunar strokes and infarcts: a review. Neurology. 1982; 32: 871–876.
Victor M, Ropper AH, Cerebrovascular diseases. In: Victor M, Ropper AH, eds. Adams and Victor’s Principles of Neurology. New York: McGraw-Hill; 1989: 617–692.