Low ankle-brachial index tied to cognitive decline
Even in the absence of peripheral arterial disease, a lower ankle-brachial index (ABI) is significantly associated with larger declines in cognitive function, according to a poster presented at the 2018 Congress of the Asian Pacific Society of Cardiology (APSC 2018) in Taipei, Taiwan.
“The present study aimed to investigate whether a graded association between ABI and cognitive function exists, and whether this association is independent of artery stiffness, which is a recognized predictor of cognitive impairment,” said researchers.
Categorizing 708 participants according to quartiles of ABI, researchers found that there was a significant and inverse correlation between ABI values and global cognitive function, represented as scores in the Mini-Mental Short Examination (MMSE; p=0.0011 for trend). [APSC 2018, abstract P006]
Specifically, mean MMSE scores were lowest in the first ABI quartile (27.4±3.1) and increased in the second (27.8±2.8), third (28.2±2.3) and fourth (28.4±2.0) quartiles.
The significant relationship between ABI and global cognitive function was confirmed in general linear (β, –0.137; p=0.0007) and fully adjusted multivariable logistic regression models (Q4 vs Q1: adjusted odds ratio [OR], 3.623; 95 percent CI, 1.096–11.972).
Researchers likewise found a significant and positive relationship between MMSE scores and carotid-femoral pulse wave velocity (CF-PWV; β, 0.114; p=0.0044).
Notably, using patients with both high ABI and low PWV as reference, the odds of cognitive function decline was elevated in those with high PWV only (OR, 2.34) and low ABI only (OR, 2.28). The effect was substantially more pronounced in those with both low ABI and high PWV (OR, 8.19).
ABI also showed a significant and inverse association with mean brachial pulse pressure (Q1: 58.3±11.8; Q2: 56.6±13.2; Q3: 54.7±10.6; Q4: 54.9±10.6 mm Hg; p=0.0094 for trend). There was a significantly higher proportion of male patients in the third (58.52 percent) and fourth (57.30 percent) ABI quartiles than in the first (35.16 percent) and second (42.42 percent; p<0.0001 for trend).
The findings of the present study show that a lower ABI value is significantly associated with a greater decline in global cognitive function, said researchers. In addition, the relationship was independent of and additive to the effect of arterial stiffness.
For the study, researchers recruited 708 adults without peripheral arterial disease (ABI >0.9; mean age 69.0±7.0 years; 48.35 percent male). Volume-plethysmographic apparatus was used to measure ABI, while CF-PWV was used as a measure of arterial stiffness.
Of the participants, 182 had ABI from 0.9–1.10 and were placed in the lowest quartile (mean age 69.3±7.1 years) while 165 had ABI from 1.10–1.14 and fell within the second quartile (mean age 69.1±6.9 years). The third (ABI 1.14–1.19; mean age 68.8±7.3 years) and fourth (ABI ≥1.19; mean age 68.9±6.6 years) quartiles included 176 and 185 participants, respectively.