Present and past hypertension in ADNI3 individuals with sub‐threshold total Hachinski ischemic score reflect greater hyperintensity burden irrespective of cognitive status

Abstract

AbstractBackgroundThe Hachinski ischemic score (HIS) scale is used to exclude as much as possible, individuals with dominant cerebrovascular pathology from those with dominant AD pathology. White matter hyperintensities (WMH) are the gold‐standard for evaluating cerebrovascular pathology and linked to worsening cognitive impairment. HIS ≤ 4 are used to minimize non‐AD pathology in ADNI participants. Here we sought to understand whether HIS scores for hypertension (HMHYPERT) in ADNI3 were associated with greater WMH burden (and hence cerebrovascular pathology) even within individuals with HIS ≤ 4.MethodWe compared HMHYPERT scores between individuals with normal cognition (CN) and with mild cognitive impairment (MCI), and participants and correlated with percent WMH burden. A total of 263 subjects screened for ADNI3 (92 MCI [38 F], age = 73 ± 6; 146 CN [94 F], age = 74 ± 7) who had HIS scores and FLAIR MRI acquisitions within a year of each other. 25 All AD participants were excluded. WMH burden was calculated by segmenting them using the Lesion Segmentation Toolbox and normalizing their volume by total intracranial volume. We used the HMHYPERT as a vascular risk factor, excluding those with any focal neurological symptoms. For analysis, we dichotomized participants into those with HMHYPERT = 0 and HMHYPERT>0. To examine whether a non‐zero HMHYPERT score corresponds to greater WMH burden, we examined the prevalence of WMH in between these 2 groups and within the MCI and CN groups.ResultAlthough not significant, HMHYPERT scores were higher in MCI. (Fig. 1A, MCI = 0.48±0.50, CN = 0.39±0.49). We found a greater proportion of MCI subjects had HMHYPERT>0 than CN subjects (Fig. 1B, HMHYPERT = 0: CN = 61.0% and MCI = 52.2%; HMHYPERT > 0: CN = 40.0% and MCI = 48.1%). WMH burden was greater in MCI (0.33±0.53) than CN (0.20±0.32) (Fig. 2A). MCI participants with HMHYPERT>0 had the highest WMH burden followed by MCI participants with HMHYPERT = 0, CN with HMHYPERT >0, and CN with HMHYPERT = 0 had the lowest WMH burden. (Fig. 2B).ConclusionCerebrovascular pathology increases significantly with diagnosis, but its severity increases further with findings of hypertension even when total HIS ≤ 4.