Contrast-induced acute kidney injury (CI-AKI) is the third leading cause of acute kidney injury deriving from the intravascular administration of contrast media in diagnostic and therapeutic procedures and leading to longer in-hospital stay and increased short and long-term mortality. Its pathophysiology, although not well-established, revolves around medullary hypoxia paired with the direct toxicity of the substance to the kidney. Critically ill patients, as well as those with pre-existing renal disease and cardiovascular comorbidities, are more susceptible to CI-AKI. Despite the continuous research in the field of CI-AKI prevention, clinical practice is based mostly on periprocedural hydration. In this review, all the investigated methods of prevention are presented, with an emphasis on the latest evidence regarding the potential of RenalGuard and contrast removal systems for CI-AKI prevention in high-risk individuals.

Robotic-assisted laparoscopic prostatectomy (RALP) requires intraoperative fluid restriction to maintain the optimal view of the operative field during vesicourethral anastomosis and to prevent upper airway edema that may occur due to the steep Trendelenburg position. The aim of this study was to demonstrate that our fluid restriction regimen would not increase postoperative serum creatinine (sCr) levels in patients undergoing RALP. The fluid regimen involved maintaining a crystalloid infusion at 1 ml/kg/h until completion of vesicourethral anastomosis, then rapid infusion of 15 ml/kg within 30 min, followed by maintenance at 1.5 ml/kg/h until post-operative day (POD) 1. The primary outcome of this study was the change in the sCr level from baseline to POD7. Secondary outcomes were the sCr levels on PODs 1 and 2, the surgical view during vesicourethral anastomosis, and the incidences of re-intubation and acute kidney injury (AKI). Sixty-six patients were eligible for the analysis. The paired t test for non-inferiority showed no significant difference in sCr levels between baseline and POD7 (mean ± standard deviation, 0.79 ± 0.14 vs. 0.80 ± 0.18 mg/dl, p < 0.001). Seven patients developed AKI on POD1, but all but one recovered on POD2. Ninety-seven percent of operations were rated as having a good view of the operative field. There were no cases of re-intubation. This study demonstrated that the fluid restriction regimen of 1 ml/kg/h until completion of vesicourethral anastomosis created a good view of the operative field during vesicourethral anastomosis without increasing postoperative sCr levels in patients undergoing RALP. Trial registration: This trial was registered in the University Hospital Medical Information Network under registration number UMIN000018088 (registration date; July 1, 2015).

Patients with chronic kidney disease (CKD) undergoing coronary angiography (CAG) are at high risk of contrast-associated acute kidney injury (CA-AKI) and mortality. Therefore, there is a clinical need to explore safe, convenient, and effective strategies for preventing CA-AKI.

This study sought to assess whether simplified rapid hydration is noninferior to standard hydration for CA-AKI prevention in patients with CKD.

This multicenter, open-label, randomized controlled study was conducted across 21 teaching hospitals and included 1,002 patients with CKD. Patients were randomized to either simplified hydration (SH) (SH group, with normal saline from 1 hour before to 4 hours after CAG at a rate of 3 mL/kg/h) or standard hydration (control group, with normal saline 12 hours before and 12 hours after CAG at a rate of 1 mL/kg/h). The primary endpoint of CA-AKI was a ≥25% or 0.5-mg/dL rise in serum creatinine from baseline within 48 to 72 hours.

CA-AKI occurred in 29 of 466 (6.2%) patients in the SH group and in 38 of 455 (8.4%) patients in the control group (relative risk: 0.8; 95% CI: 0.5-1.2; P = 0.216). In addition, the risk of acute heart failure and 1-year major adverse cardiovascular events did not differ significantly between the groups. However, the median hydration duration was significantly shorter in the SH group than in the control group (6 vs 25 hours; P < 0.001).

In CKD patients undergoing CAG, SH is noninferior to standard hydration in preventing CA-AKI with a shorter hydration duration.

T he objective of this study is to evaluate oral hydration compared to intravenous (i.v.) hydration in the prevention of post-contrast acute kidney injury (PC-AKI) in the oncologic subgroup of patients with stage IIIb chronic kidney disease (CKD) included in the NICIR study referred for elective contrast-enhanced computed tomography (CE-CT).

We performed a retrospective subanalysis of the oncological subgroup (174/228 patients, 74%) from a continuous prospective database of patients included in the recently published non-inferiority NICIR study. Patients received prophylaxis against PC-AKI with either oral hydration (500 mL of water 2 h before and 2000 mL during the 24 h after CE-CT) or i.v. hydration (sodium bicarbonate (166 mmol/L) 3 mL/kg/h starting 1 h before and 1 mL/kg/h during the first hour after CE-CT). The primary outcome was to compare the proportion of PC-AKI in the first 48 to 72 h after CE-CT in the two hydration groups. Secondary outcomes were to compare persistent PC-AKI, the need for haemodialysis, and the occurrence of adverse events related to prophylaxis in each group.

Of 174 patients included in the subanalysis, 82 received oral hydration and 92 received i.v. hydration. There were no significant differences in clinical characteristics or risk factors between the two study arms. Overall the PC-AKI rate was 4.6% (8/174 patients), being 3.7% in the oral hydration arm (3/82 patients) and 5.4% (5/92 patients) in the i.v. hydration arm. The persistent PC-AKI rate was 1.2% (1/82 patients) in the oral hydration arm and 3.3% (3/92 patients) in the i.v. hydration arm. No patient required dialysis during the first month after CE-CT or had adverse effects related to the hydration regime.

In oncological patients with stage IIIb CKD referred for elective CE-CT, the rate of PC-AKI in those receiving oral hydration did not significantly differ from that of patients receiving i.v. hydration.

To evaluate the non-inferiority of oral hydration compared to intravenous (i.v.) hydration in the prevention of post-contrast acute kidney injury (PC-AKI) in patients with stage IIIb chronic kidney disease (CKD) referred for an elective contrast-enhanced computed tomography (CE-CT).

This is a prospective, randomized, phase 3, parallel-group, open-label, non-inferiority trial. Patients were randomly assigned 1:1 to receive prophylaxis against PC-AKI either with oral hydration: 500 mL of water two hours before and 2000 mL during the 24 h after performing CE-CT or i.v. hydration: sodium bicarbonate (166 mmol/L) 3 mL/kg/h starting one hour before and sodium bicarbonate (166 mmol/L) 1 mL/kg/h during the first hour after CE-CT. 100 mL of non-ionic iodinated contrast was administered in all cases. The primary outcome was the proportion of PC-AKI in the first 48-72 h after CE-CT. Secondary outcomes were persistent PC-AKI, the need for hemodialysis, and the occurrence of adverse events related to prophylaxis.

Of 264 patients randomized between January 2018 and January 2019, 114 received oral hydration, and 114 received i.v. hydration and were evaluable. No significant differences were found (p > 0.05) between arms in clinical characteristics or risk factors. PC-AKI rate was 4.4 % (95 %CI: 1.4-9.9 %) in the oral hydration arm and 5.3 % (95 %CI: 2.0-11.1%) in the i.v. hydration arm. The persistent PC-AKI rate was 1.8 % (95 %CI: 0.2-6.2 %) in both arms. No patient required dialysis during the first month after CE-CT or had adverse effects related to the hydration regime.

In those with stage IIIb CKD referred for an elective CE-CT, we provide evidence of non-inferiority of oral hydration compared to i.v. hydration in the prevention of PC-AKI.

Prevention of postcontrast acute kidney injury in patients with stage 3 chronic kidney disease (CKD) by means of prehydration has been standard care for years. However, evidence for the need for prehydration in this group is limited.

To assess the renal safety of omitting prophylactic prehydration prior to iodine-based contrast media administration in patients with stage 3 CKD.

The Kompas trial was a multicenter, noninferiority, randomized clinical trial conducted at 6 hospitals in the Netherlands in which 523 patients with stage 3 CKD were randomized in a 1:1 ratio to receive no prehydration or prehydration with 250 mL of 1.4% sodium bicarbonate administered in a 1-hour infusion before undergoing elective contrast-enhanced computed tomography from April 2013 through September 2016. Final follow-up was completed in September 2017. Data were analyzed from January 2018 to June 2019.

In total, 262 patients were allocated to the no prehydration group and 261 were allocated to receive prehydration. Analysis on the primary end point was available in 505 patients (96.6%).

The primary end point was the mean relative increase in serum creatinine level 2 to 5 days after contrast administration compared with baseline (noninferiority margin of less than 10% increase in serum creatinine level). Secondary outcomes included the incidence of postcontrast acute kidney injury 2 to 5 days after contrast administration, mean relative increase in creatinine level 7 to 14 days after contrast administration, incidences of acute heart failure and renal failure requiring dialysis, and health care costs.

Of 554 patients randomized, 523 were included in the intention-to-treat analysis. The median (interquartile range) age was 74 (67-79) years; 336 (64.2%) were men and 187 (35.8%) were women. The mean (SD) relative increase in creatinine level 2 to 5 days after contrast administration compared with baseline was 3.0% (10.5) in the no prehydration group vs 3.5% (10.3) in the prehydration group (mean difference, 0.5; 95% CI, -1.3 to 2.3; P < .001 for noninferiority). Postcontrast acute kidney injury occurred in 11 patients (2.1%), including 7 of 262 (2.7%) in the no prehydration group and 4 of 261 (1.5%) in the prehydration group, which resulted in a relative risk of 1.7 (95% CI, 0.5-5.9; P = .36). None of the patients required dialysis or developed acute heart failure. Subgroup analyses showed no evidence of statistical interactions between treatment arms and predefined subgroups. Mean hydration costs were €119 (US $143.94) per patient in the prehydration group compared with €0 (US $0) in the no prehydration group (P < .001). Other health care costs were similar.

Among patients with stage 3 CKD undergoing contrast-enhanced computed tomography, withholding prehydration did not compromise patient safety. The findings of this study support the option of not giving prehydration as a safe and cost-efficient measure.

Netherlands Trial Register Identifier: NTR3764.