Feasibility study of the RenalGuard™ balanced hydration system: a novel strategy for the prevention of contrast-induced nephropathy in high risk patients.

BACKGROUND: Contrast-induced nephropathy (CIN) is a frequent complication following angiographic procedures with significant impact on healthcare costs, and long-term outcomes. Multiple reno-protective strategies have been studied but few have shown benefit in prospective randomized studies beyond limiting the exposure to iodinated contrast and adequate intravenous. We studied the performance and safety of a novel system designed to achieve precise real-time high volume fluid balance using a closed loop hydration monitoring and infusion system.

METHODS: This prospective, multi-center, FDA approved phase II feasibility study was designed to evaluate the safety and the performance of the RenalGuard matched hydration system. Between October 2006 and November 2007, twenty-three subjects at high risk for CIN (with an estimated glomerular filtration rate (eGFR)<50ml/min/1.73m(2)) undergoing diagnostic or therapeutic catheterization were treated with the system. The primary endpoint of the study was defined as the ability of the system to effectively dynamically match fluid administration to urine output.

RESULTS: The 23 subjects at high risk for CIN enrolled had a mean±SD eGFR of 39±9.3. Patients achieved an hourly urine flow rate of 620±400ml/h. The system had a mean effectiveness rate of 99.9% over the duration of therapy with an average saline volume infused of 3825ml closely matched, minute to minute, to urine output of 3579ml. There were no major device-related complications from the experimental therapy, though one patient developed hypokalemia requiring replacement. Two subjects (9.5%) developed CIN as defined by >0.5mg/dl or >25% rise in serum creatinine at 48-60h post contrast administration when compared with the baseline.

CONCLUSION: The study confirmed that the RenalGuard(TM) system is safe and dynamically balances volume hydration with urine production. Further randomized studies are needed to confirm the efficacy of the system in reducing the incidence of CIN.