Renal tubulointerstitial tissue damage, central pressure and vascular function in patients with untreated primary arterial hypertension

Abstract

Background The aim of the study was to examine the correlation of the conventional method of arterial pressure measurement in the brachial artery and non-invasive aortic pressure measurement by applanation tonometry with vascular and left ventricular structure and function. An attempt was made at determining a correlation of morphological and functional changes within the cardiovascular system with selected parameters of renal filtration function and the renal interstitium in patients with previously untreated primary arterial hypertension. Material and methods 25 patients with untreated primary arterial hypertension without albuminuria and 15 healthy volunteers underwent arterial pressure measurement with a standard mercury sphygmomanometer using the Korotkoff technique and non-invasive measurement of aortic pressure by applanation tonometry using a SphygmoCor device. For all subjects, the concentrations of creatinine, uric acid, 1,25(OH)2D3, erythropoietin, and 25-hour NAG excretion were determined and GFR was estimated using the MDRD equation. PWV measurement was performed using a SphygmoCor device, whereas IMT was measured by ultrasound. Results Hypertensive patients showed higher values of arterial pressure compared to the control group: SBP, DBP, PP, MAP, as well as CSP, CDP, CPP and MCAP. In both the studied and the control group, the following statistically significant positive correlations were found: CPP vs IMT and CPP vs AIx. Only in the studied group, the following positive linear correlations were found: NAG vs PWV (R = 0.46; p = 0.019); NAG vs IMT (R = 0.36; p = 0.078). In the multiple regression model, a statistically significant positive effect was found of PWV and IMT [PWV (b 0.41; p = 0.0158), IMT (b 0.49; p = 0.0048)] on the dependent variable NAG (R2 = 0.503) in hypertensive patients. eGFR or uric acid concentration in serum included additionally in the model had no statistically significant effect on the dependent variable NAG (p = 0.9307 and p = 0.4938, respectively). Conclusions Damage to the renal tubulointerstitial tissue in hypertensive patients is concomitant with a decrease in vascular resistance. CPP may constitute a useful parameter for assessing the development of atherosclerotic lesions in vessels and the function of the left ventricle of the heart.