Ankle-brachial index (ABI) and femoral-ankle pulse wave velocity (PWV), which measure lower-limb atherosclerosis and arteriosclerosis, respectively, have demonstrated independent associations with cardiovascular disease (CVD) risk, according to a study published in Atherosclerosis.
The study included 4330 adults with a mean age of 75.3±5.0 years, among whom 22.3% were Black and 59.5% were women. Both ABI and femoral-ankle PWV were evaluated using an oscillometric screening device. Mixed-model logistic and linear regression was used to identify associations between ABI/femoral-ankle PWV and CVD/CVD risk factors. Independent variables included systolic blood pressure (BP), high-density lipoprotein (HDL), total cholesterol (TC), sex, age, smoking, and diabetes.
A positive association was identified between ABI and femoral-ankle PWV (R2 =0.039). A negative correlation was found between ABI and age (r =-0.08; P <.001), while a positive association was found between femoral-ankle PWV and age (r =0.04; P =.004). The study researchers observed positive associations between ABI and men and HDL, while it was negatively associated with TC, diabetes, and smoking. Femoral-ankle PWV was positively associated with systolic BP and HDL and negatively associated with smoking. ABI and femoral-ankle PWV were both inversely associated with CVD; low values of each (ABI: ≤0.9 vs >0.9; femoral-ankle PWV: ≤9.94 vs >9.94) were associated with increased CVD risk (2.41-fold and 1.46-fold, respectively). ABI and CVD risk factors did not change the inverse association between femoral-ankle PWV and CVD.
Limitations to this study include a lack of causal inferences, potential residual confounding, limited generalizability, and potential bias.
The study researchers concluded that, while “lower-limb atherosclerosis may be a more sensitive marker of CVD, [femoral-ankle] PWV, an assessment of lower-limb arteriosclerosis, is independently associated CVD beyond ABI, and therefore may confer unique and additive CVD risk information.” However, they noted that “future work is warranted to; i) confirm if combined [femoral-ankle] PWV and ABI measures improve prediction of CVD outcome beyond ABI alone, and ii) identify the mechanisms leading to low [femoral-ankle] PWV and its role in heightening CVD risk.”
Stone K, Fryer S, Faulkner J, et al. Associations of lower-limb atherosclerosis and arteriosclerosis with cardiovascular risk factors and disease in older adults: the Atherosclerosis Risk in Communities (ARIC) study. Atherosclerosis. Published online November 2, 2021. doi:10.1016/j.atherosclerosis.2021.10.014