Following a 10 min rest period measurements of BP and arterial stiffness were taken with the TensioMed™ Arteriograph monitor (TensioMed Ltd, Hungary). Measurements were taken as the average of two readings. The Arteriograph utilises brachial pulse oscillations to calculate aortic pulse wave velocity (PWV), augmentation index (AIx), systolic BP and pulse pressure. It also records brachial systolic BP and diastolic BP. The Arteriograph has been validated against an invasive measure of aortic PWV8 and two commonly used non-invasive measurement devices, the Complior and SphygmoCor9,10.
Blood was sampled routinely for serum creatinine. Creatinine clearance, as an estimate of GFR, was calculated according to the CKD-EPI equation