LAUSR

In this issue of Angiology, Puvvula et al report that both carotid intima-media thickness (IMT) and carotid plaque burden, measured as total plaque area (TPA), were increased in patients with impaired renal function, assessed as estimated glomerular filtration rate (eGFR). A recent editorial in this journal explained why measuring plaque burden is superior to measuring IMT, which is biologically and genetically distinct from atherosclerosis, and can be regarded as obsolete technology. Puvvula et al studied 678 participants with a mean age of only 54.2 + 9.8 years, so they observed relatively small effects of renal impairment on IMT and atherosclerosis. Total plaque area increases steeply with age (Figure 1A), so effects of impaired renal function are more evident among older patients. Figure 1B shows TPA by quartiles of eGFR among patients (n1⁄4 3967) aged 62.6 + 13.7 years, attending the Stroke Prevention and Atherosclerosis Research Centre, in London, Canada. This is not a new observation; it has been known for many years that impaired renal function markedly increases cardiovascular risk and increases atherosclerosis burden, particularly in diabetic patients. Renal failure also increases the risk of stroke and cerebral microbleeds. What is new is a better understanding of the mechanisms by which renal failure increases risk of stroke and coronary artery disease and aggravates atherosclerosis. Patients with chronic kidney disease (CKD) have high plasma levels of phosphates, asymmetric dimethylarginine (a nitric oxide antagonist), and total homocysteine (tHcy); however, tHcy probably only accounts for *20% of the excess plaque related to impaired renal function. Levels of thiocyanate, a powerful oxidant, are high in renal failure and excretion of cyanide as thiocyanate probably Figure 1. Carotid total plaque area (TPA) by age-group and quartile of estimated glomerular filtration rate (eGFR ) Among patients attending the Stroke Prevention & Atherosclerosis Research Centre, London, Canada (n 1⁄4 3977), TPA increases steeply with age (A), and with impaired renal function (B); eGFR (mL/min/1.73 m) was calculated by the chronic kidney disease (CKD)-Epi equations. At any age, and at any level of renal function, women have less plaque than men. (The figures have not previously been published; they were drawn from the database of a previous study).