RenalGuard system to prevent contrast-induced acute kidney injury in Japanese patients with renal dysfunction; RESPECT KIDNEY study

Increasing the urine flow rate (UFR) reduces the toxic effect of contrast media. Use of the RenalGuard system enables the achievement of a high UFR by maintaining intravascular volume and prevents the development of contrast-induced acute kidney injury (CI-AKI). However, the efficacy and safety of RenalGuard system have not yet been evaluated in Japan. This multicenter prospective study evaluated the efficacy and safety of the RenalGuard therapy in preventing CI-AKI development in 60 Japanese patients with renal dysfunction [estimated glomerular filtration rate (eGFR) < 45 mL/min/1.73 m ² ] undergoing catheter procedures. Baseline eGFR and Mehran’s CIN (contrast-induced nephropathy) risk score were 35.1 ± 8.5 mL/min/1.73 m ² and 11.7 ± 4.3, respectively. Regardless of this high-risk profile, the incidence of CI-AKI was 8.6% (5/58) compared with the 26.1% incidence estimated by the CIN risk score. Moreover, two-sided 95% (Fisher’s) exact confidence interval was 2.9–19.0 and its upper limit (i.e., 19.0) was less than the prespecified threshold incidence of 25.0. Univariate logistic regression analysis demonstrated that the UFR during catheter procedure was one of the most important factor associated with CI-AKI (odds ratio 0.99, confidence interval 0.98–1.00, p = 0.03). In conclusion, RenalGuard therapy may prevent CI-AKI development in Japanese patients with renal dysfunction. Further large-scale prospective multicenter studies are necessary to confirm our findings.