Cardiovascular diseases and hippocampal infarcts

The prevalence of hippocampal lesions such as hippocampal infarcts have not been studied in detail even though hippocampal alterations are known to be associated with various clinical conditions such as age-related degenerative disorders and epilepsy.

Here we defined the hippocampal infarcts and assessed the prevalence of this lesion in large unselected population of 1,245 subjects age ranging from 1 to 99 years (mean age 79 ± 1 S.E.M). Furthermore, we assessed the association of these lesions with various cardio- and cerebro-vascular disorders and other neurodegenerative lesions. The prevalence of hippocampal infarct in the study population of 1,245 subjects was 12%, increasing to 13% when only those with a clinically diagnosed cognitive impairment (n = 311) were analyzed. Large hemispheric brain infarcts were seen in 31% of the study subjects and these lesions were strongly associated with cardiovascular risk factors such as hypertension (43%), coronary disease (32%), myocardial infarct (22%), atrial fibrillation (20%), and heart failure (20%). In contrast, hippocampal infarcts displayed a significant association only with large hemispheric brain infarct, heart failure, and cardiovascular index as assessed postmortem. It is noteworthy that only widespread hippocampal infarcts were associated with clinical symptoms of cognitive impairment or epilepsy. The surprisingly low prevalence of 12% of hippocampal infarcts in aged population found here and the failure to detect an association between this lesion and various cerebro- cardio-vascular lesions is intriguing. Whether susceptibility to ischemia in line with susceptibility to neuronal degeneration in this region is influenced by still undetermined risk- factors need further investigation. Furthermore it should be noted that the size of the hippocampal tissue damage, i.e., small vs. large cystic infarcts is of significance regarding clinical alterations.