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06-04-2011 | Cardiology | Article

REMEDIAL II: Hydration system protects kidneys from contrast-induced injury


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MedWire News: A system for aggressively hydrating patients undergoing imaging with contrast media is more effective at preventing acute contrast-induced kidney injury (CI-AKI) than standard prophylaxis with sodium bicarbonate and N-acetylcysteine (NAC), according to results of the REMEDIAL II trial.

The trial, presented this week at the American College of Cardiology Annual Scientific Sessions in New Orleans, Louisiana, USA, compared conventional hydration with the RenalGuard System (PLC Medical Systems Inc, Franklin, Massachusetts, USA), a closed-loop fluid management system that provides high-volume fluid balance for use during image-guided procedures.

Control patients received sodium bicarbonate solution and NAC, while patients using RenalGuard received normal saline, NAC, and furosemide controlled by the system. The system was associated with a significantly higher urine output at 24 hours, relative to the control strategy, and with a lower incidence of CI-AKI.

Specifically, at 48 hours, 11.0% of 146 patients in the RenalGuard group had a serum creatinine increase of at least 0.3 mg/dl, compared with 20.5% of 146 controls, giving an odds ratio for CI-AKI of 0.47 (p=0.025).

"RenalGuard therapy, including hydration with normal saline plus high-dose NAC controlled by the system, in combination with a very little dose of furosemide, is an effective strategy to prevent contrast-induced acute kidney injury in a high-risk population," said lead investigator Carlo Briguori (Clinica Mediterranea, Naples, Italy).

The rate of CI-AKI in patients undergoing imaging-guided procedures can exceed 50% in patients with a combination of high-risk characteristics such as hypotension, congestive heart failure, age above75 years, [to cut down list length]and increased contrast media volume, Briguori said.

Previous studies have shown that increasing urine flow rate reduces the toxic effects of contrast media, but forced diuresis with furosemide (Lasix) may be harmful, potentially from a negative fluid balance. The RenalGuard system controls fluid delivery and output through a closed-loop system, with fluid delivered intravenously and urine removed via a Foley catheter.

The REMEDIAL (REnal insufficiency following contrast MEDIA administration) II trial compared conventional hydration with the RenalGuard system in 292 adults who had chronic kidney disease and were at a high risk for CI-AKI, defined as an estimated glomerular filtration rate of ≤30 ml/min/1.73 m2, or a Mehran contrast nephropathy risk score of 11 or more. The majority (72.5%) of patients had a Mehran score between 11 and 15, and 12.5% were at the highest risk for CK-AKI.

Conventional hydration consisted of intravenous sodium bicarbonate 3 ml/kg 1 hour before and 1 ml/kg for 6 hours after the procedure, and NAC 1200 mg twice-daily for 2 days, with 1.5 g administered during the procedure. Patients on the system received normal saline to achieve a urine flow of ≥300 ml/hour, and NAC 1.5 g/l, plus furosemide 0.25 mg/kg.

In addition to halving the risk for CI-AKI, the system was significantly better than conventional hydration at reducing both changes in serum creatinine at 24 hours and changes in cystatin C at 48 hours; however, there were no significant differences in cystatin C at 24 hours.

Significantly fewer patients on the system required dialysis within 30 days (0.7% vs 4.8%, respectively; p=0.031), but there were no significant differences in 30-day incidence of pulmonary edema (2.1% vs. 0.7%, respectively; p=0.62), or death (4.1% in each group).

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Neil Osterweil

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