P147 ASSOCIATIONS BETWEEN RESERVOIR PRESSURE PARAMETERS AND KIDNEY FUNCTION ARE DEPENDENT ON THE ARTERIAL MEASUREMENT SITE

Abstract

Introduction: Reservoir pressure parameters derived from pressure waveforms captured at various arterial sites predict adverse kidney function independently of conventional cuff blood pressure (BP). However, there has never been an analysis directly comparing if associations with kidney function may differ depending on arterial site of measurement, which was the aim of this study. Methods: Intra-arterial BP waveforms were measured via fluid filled catheter at the ascending aorta, brachial and radial arteries in 172 people undergoing coronary angiography (aged 60 ± 13 years, 67% male). Customised Matlab software was used to derive reservoir pressure and associated parameters of excess pressure, diastolic and systolic rate constants at each arterial site. Kidney function was determined by estimated glomerular filtration rate (eGFR). Results: Reservoir and excess pressure derived from BP waveforms measured at the aorta were associated with eGFR (r = −0.26, and r = −0.24, p < 0.01, respectively), but not from brachial or radial BP waveforms (r < −0.14, p > 0.07 all). However, diastolic rate constants from BP waveforms at all arterial sites were significantly associated with eGFR. These associations remained following adjustment for aortic systolic BP, heart rate, sex, and body mass index (β = −0.37, p = 0.001; β = −0.37, p = 0.003; β = −0.25, p = 0.02 respectively). Systolic rate constants were not significantly associated with eGFR at any arterial site. Conclusion: Associations between reservoir pressure parameters and kidney function are dependent on site of waveform measurement, with exception of the diastolic rate constant, which independently relates to kidney function irrespective of location. This is of clinical relevance since this variable can be derived from non-invasively recorded peripheral BP waveforms.