Albuminuria as a marker of arterial stiffness in chronic kidney disease patients.

AIM: To access the association between albuminuria levels and arterial stiffness in non-diabetic patients with hypertension and chronic kidney disease (CKD) stages 1-2, treated with renin angiotensin blockade agents plus other hypertensive drugs when needed. METHODS: One hundred fifteen patients [median age 52 years (68% males)] were consequently enrolled in the study. For each patient, we recorded gender, age, body mass index (BMI), peripheral systolic blood pressure (pSBP), peripheral diastolic blood pressure, peripheral pulse pressure, central systolic blood pressure (cSBP), central diastolic blood pressure (cDBP), central pulse pressure (cPP), hematocrit, hemoglobin, hsCRP, total cholesterol triglycerides, high-density lipoprotein-C, low-density lipoprotein-C, calcium, phosphorus, parathormone, and albumin, as well as 24 h urine albumin excretion. According to 24-h urine albumin collection, patients were then classified as those with moderately increased albuminuria (formerly called macroalbuminuria) (≤ 300 mg/d) and those with severely increased albuminuria (formerly called macroaluminuria (> 300 mg/d). We considered aortic stiffness (AS) indices [carotid femoral pulse wave velocity (PWVc-f) and augmentation index (AIx)] as primary outcomes of the study. We explored potential correlations between severely increased albuminuria and AS indices using a multiple linear regression model. RESULTS: Fifty-eight patients were included in the moderately increased albuminuria group and 57 in the severely increased albuminuria. Blood pressure measurements of the study population were 138 ± 14/82 ± 1.3 mmHg (systolic/diastolic). There were no significant differences in age, sex, and BP measurements between the two groups. Patients with severely increased albuminuria had higher PWV and AIx than patients with moderately increased albuminuria (P < 0.02, P < 0.004, respectively). In addition these patients exhibited higher BMI (P < 0.03), hsCRP (P < 0.001), and fibrinogen levels (P < 0.02) compared to patients with moderately increased albuminuria. In multivariate linear regression analysis, severely increased albuminuria (ß = 1.038, P < 0.010) pSBP (ß = 0.028, P < 0.034) and Ht (ß = 0.171, P = 0.001) remained independent determinants of the increased PWVc-f. Similarly, severely increased albuminuria (ß = 4.385, P < 0.012), cSBP (ß = 0.242, P < 0.001), cPP (ß = 0.147, P < 0.01) and Ht levels (ß = 0.591, P < 0.013) remained independent determinants of increased AIx. CONCLUSION: These findings demonstrate an independent association between AS indices and severely increased albuminuria in non-diabetic, hypertensive patients with CKD stages 1-2 treated with renin angiotensin aldosterone system blockers.

Aliskiren in an alternate-day administration schedule in hypertensive albuminuric patients.

OBJECTIVE: It has been suggested that aliskiren has a long half-life and maintains a blood pressure (BP)-lowering effect following a missed dose. We tested the hypothesis that every other day (eod) administration of aliskiren has the same effects as the once daily (od) dosing in albuminuric hypertensive patients. METHODS: Fifteen hypertensive patients, after a 4-week wash-out period on clonidine, received 300 mg aliskiren od as the sole treatment. In patients who remained out of target, other nonrenin-angiotensin system blockers were added. Patients who completed a 24-week (w24) treatment period were switched to eod administration of aliskiren for an additional period of 24 weeks (w48). RESULTS: Thirteen patients completed the full study protocol. The mean office BP was reduced at the end of w24 (-9/3 mmHg), a reduction that continued to be observed at w48 (-11/1 mmHg). At the end of the study, the 48 h ambulatory BP monitoring was divided into two 24 h periods. The mean 24 h systolic BP, and the mean daytime systolic and diastolic BP were significantly lower (P<0.05) in the first 24 h (when aliskiren was taken) compared with the second period. Central hemodynamics showed no significant differences at any time during monitoring. Administration of aliskiren resulted in a median reduction of urine albumin/creatinine ratio of 103 mg/g (od) and 102 mg/g (eod). Differences in plasma renin activity, plasma renin concentration, and aldosterone-level measurements were not significant. CONCLUSION: The BP-lowering effect of eod aliskiren administration, although adequate, is less efficient compared with od administration, despite the fact that in terms of reducing albuminuria, it appears to be effective.

Inorganic phosphorus homeostasis during the first hour of dialysis.

BACKGROUND/AIM: Hyperphosphatemia is a well-recognized complication of chronic kidney disease, and phosphorus kinetics during hemodialysis (HD) remains a vague area of investigation. We studied the inorganic phosphorus homeostasis during the first hour of an HD session. MATERIALS/METHODS: Twelve patients were studied twice, in two consecutive HD sessions. Total (TPR), extracellular (EPR), and intracellular (IPR) phosphorus mass removal was determined using the direct dialysate quantification (DDQ) method. Alterations of serum inorganic phosphorus (sP), erythrocyte intracellular phosphorus (P(ERY)), and 2,3-diphosphoglycerate (2,3-DPG) concentrations were measured before HD initiation and at 1, 2, 3, 4, 5, 10, 30, and 60 min. RESULTS: The contribution of IPR to TPR was negative in the first 10 min of both HD sessions (-27.2 ± 6.5 and -26.4 ± 58 mmol, respectively, p = ns) while the contribution of the IPR to TPR increased as the time elapsed. Intracellular phosphorus and 2,3-DPG remained almost unchanged during the 60 min of HD session. CONCLUSIONS: Unchanged P(ERY) concentration during the first hour of an HD session does not reject the hypothesis of a simultaneous efflux and influx of phosphorus from/to intracellular compartment.