Are you really as old as your arteries?
Fran Kirkham is an F2 doctor at the Royal Sussex County Hospital in Brighton, having graduated from the Cambridge Graduate Course in Medicine in 2016. She originally did an English degree at Cambridge University and worked in PR and Communications for 7 years. She hopes to pursue a career in Community Geriatrics. She is one of the BGS’s Deputy Digital Media Editors. She tweets @fran_kirkham
The association between age and vascular parameters has been recognised for centuries, since 17th century physician Thomas Sydenham famously claimed that “a man is as old as his arteries.” In recent years, the architecture and actions of arteries have gained increasing importance in understanding the cardiovascular system, with arterial stiffness emerging as a robust, non-invasive technique for assessing cardiovascular risk. Reduced arterial compliance has been linked to hypertension, cardio- and cerebro-vascular disease and so we wondered if it might have other uses, particularly when assessing older patients.
The notion of biological age has been recognised for many years, with scientists attempting to find biomarkers to assess the functional state of the body in comparison to its chronological age. As geriatricians, it is incredibly important to look at how well a patient’s body is functioning for their age compared to the simplistic notion of basing our judgements based on years lived. Arterial stiffness closely relates to the ageing process and while studies have evaluated the correlation with age in a predominately Asian patient group, this interaction has yet to be fully investigated in a UK population so we saw an opportunity here.
In terms of measuring arterial stiffness, pulse wave velocity (PWV – measured from the carotid to either the radial or femoral artery) is currently considered the gold standard, with well-documented correlation to cardiovascular disease outcomes. However, a newer technique, the cardio-ankle vascular index (CAVI), is becoming an increasing focus of attention, estimating whole-body vascular compliance independently of blood pressure.
With this background, we recently conducted a study to compare these measures of arterial stiffness (CAVI and PWV) as potential predictors of biological age in a UK population, hoping that they may provide a potential tool by which we could objectively assess a patient’s true age from their arteries. We looked at the correlation between these measurements with age and their interaction with other biological factors such as gender, blood pressure and BMI.
Our cohort included 312 volunteers (180 men, 132 women) ranging from 25-92 years. Our results found that both CAVI and PWV were significantly correlated with age (r=0.63, p<0.001 and r=0.37, p<0.001 respectively), with greater correlation in males than females. On multivariate regression, adjusting for gender, BP and BMI, only CAVI (beta=0.497, p<0.001) was significantly predictive of age.
Both measures do correlate with age, but our results would suggest CAVI would be the more useful measure compared to PWV. In clinical practice, measures of arterial compliance could be combined with other parameters to be used in creating tools to help us estimate a patient’s true biological age in order to guide decision-making.