Use of the RenalGuard system to prevent contrast-induced AKI: A meta-analysis

Background: Contrast-induced kidney injury (CI-AKI) following cardiovascular interventions results in increased morbidity and mortality. RenalGuard (RG) is a novel, closed loop system which balances volume administration with forced diuresis to maintain a high urine output. We performed a meta-analysis of the existing data comparing use of RG to conventional volume expansion. Methods: Ten studies were found eligible, of which four were randomized controlled trials. Of an aggregate sample size (N) of 1585 patients, 698 were enrolled in the four RCTs and 887 belonged to the remaining registries included in this meta-analysis. Primary outcomes included CI-AKI incidence and relative risk. Mortality, dialysis, and major adverse cardiovascular events (MACCE) were secondary outcomes. A random effects model was used and data were evaluated for publication bias. Results: RG was associated with significant risk reduction in CI-AKI compared to control (RR: 0.30, 95%CI: 0.18-0.50, P < 0.01). CI-AKI in RG was found to be 7.7% versus 23.6% in the control group (P < 0.01). Use of RG was associated with decreased mortality (RR: 0.43, 95%CI: 0.18-0.99, P = 0.05), dialysis (RR: 0.20, 95%CI: 0.06-0.61, P = 0.01), and MACCE (RR: 0.42, 95%CI: 0.27-0.65, P < 0.01) compared to control. Conclusions: RG significantly reduces rates of CI-AKI compared to standard volume expansion and is also associated with decreased rates of death, dialysis, and MACCE.