ABSTRACT
Objective: Since the conventional drip-infusion method for measuring inulin clearance (Cin) has problems related to its accuracy and performance, we explored a more accurate and concise method by rapid intravenous injection of a newly developed inulin fraction (Inulead®), in which spot urine sampling was omitted and the administration period of inulin was shortened from 120 to 5 minutes. Patients and Methods: Twenty seven patients (M/F: 15/12, 67.8 ± 12.9 years old) admitted to the Nephrology ward were enrolled in this study. Inulead®, 1500 mg dissolved in 150 mL of saline, was intravenously administered in 5 minutes. Then, sequential blood samplings and urine collection were performed for 24 hours. Cins were calculated by the following three formulae: (1) a pharmacokinetic analysis using a two compartments model based on the plasma inulin concentration to determine Cin, which was the administered dose divided by the area under the curve (AUC) from 0 to ∞, (2) urinary inulin excretion divided by the AUC for 24 hours and (3) the Bayesian method using a three-point set of plasma inulin concentrations to predict the change of inulin concentration to determine Cin as in 1. These Cins were compared with levels of estimated GFR (eGFR), creatinine clearance (Ccr), serum β2 microglobulin (β2MG) and serum cystatin C (Cys C). Results: Cins obtained by the above three methods were well correlated with each other (r. = 0.9088 – 0.9998) and with eGFR (r. = 0.8286 – 0.8650), Ccr (r. = 0.821 – 0.864), 1/β2MG (r. = 0.631 –0.752) and 1/CysC (r. = 0.830 – 0.857). The averaged differences of each Cin from eGFR were distributed between –4.4 and –4.5 mL/min. Conclusion: Since the Cins by rapid inulin injection showed satisfactory correlation and differences with other GFR parameters, this method will be a good alternative to the drip infusion method, and may reduce the burden of patients and medical staff.
ABSTRACT
Objective: A direct renin-inhibitor (DRI), aliskiren, was administered to anuric patients to investigate whether it can be a new optional therapy against hypertension in hemodialysis (HD) patients. Patients: The patients that received aliskiren comprised 8 males and 2 females with a mean ± SD age of 63 ± 8 years (43-72 years). They were exposed to dialysis therapy for 118 ± 73 months (8-251 months), with diabetes mellitus in 4 cases, chronic glomerulonephritis in 4 cases, and other diagnoses in 2 cases. Methods: After the plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured before an HD session, aliskiren, 150 mg as an initial dose, was administered to the patients. PRA and PAC were also examined a week after initiating aliskiren. The blood pressure (BP) levels at the start of each HD session for a period of 2 weeks (6 HD sessions) were compared between before and after administration of aliskiren. The change of doses in other antihypertensive agents was also counted. Results: The averaged reduction of mean blood pressure was 4 ± 5 mmHg, and doses of antihypertensives other than aliskiren were reduced in 4 patients. Of the examined parameters, only the reduction rate of PRA x PAC seemed correlated with the BP lowering effect of aliskiren, which was calculated as the sum of the mean BP reduction in mmHg and drug reduction with 1 tablet (capsule)/day considered to be 10 mmHg. Conclusion: A DRI, aliskiren, was effective even in anuric dialysis patients, and monitoring of PRA and PAC was valuable for selecting cases responsive to aliskiren.