Prophylactic hydration to prevent contrast-induced nephropathy: much ado about nothing?

Fluid administration strategies for the prevention of contrast-associated acute kidney injury

PURPOSE OF REVIEW

The known timing of contrast media exposure in patients identified as high-risk for contrast-associated acute kidney injury (CA-AKI) enables the use of strategies to prevent this complication of intravascular contrast media exposure. Although multiple preventive strategies have been proposed, periprocedural fluid administration remains as the primary preventive strategy. This is a critical review of the current evidence evaluating a variety of fluid administration strategies in CA-AKI.

RECENT FINDINGS

Fluid administration strategies to prevent CA-AKI include comparisons of intravenous (i.v.) to no fluid administration, different fluid solutions, duration of fluid administration, oral hydration, left ventricular end diastolic-pressure guided fluid administration and forced diuresis techniques.

SUMMARY

Despite an abundance of fluid administration trials, it is difficult to make definitive recommendations about preventive fluid administration strategies due to low scientific quality of published studies. The literature supports use of i.v. compared with no fluid administration, especially in high-risk patients undergoing intra-arterial contrast media exposure. Use of isotonic saline is recommended over 0.45% saline or isotonic sodium bicarbonate. Logistical considerations support shortened over longer i.v. fluid administration strategies, despite an absence of evidence of equivalent efficacy. Current literature does not support oral hydration for high-risk patients. The use of tailored fluid administration in heart failure patients and forced diuresis with matching fluid administration are promising new fluid administration strategies.

Evaluation of contrast nephropathy in percutaneous treatment of chronic total occlusions

Background

Contrast-induced nephropathy (CIN) is a leading cause of morbidity and mortality in patients undergoing percutaneous coronary intervention (PCI). Chronic total occlusions (CTO) are frequently observed among patients undergoing coronary angiography.

Methods

A total of 128 CTO patients were included. Mehran score, lesion characteristics, interventional procedure, serological specimens and devices were recorded. The first group was administered with 1 ml · kg^-1 · h^-1 saline (0.9% NaCl) infusion that started 12 h before the procedure and continued 12 h post procedure as recommended by the guidelines. The second group was administered with saline infusion of 12 ml · kg^-1 · h^-1 only during CTO-PCI procedure, which is called as intensive infusion.

Results

CIN development was similar in two groups (four patients in standard hydration group and five patients in intensive hydration group). The amount of saline was significantly higher in the standard group (1,767 ± 192.2 vs. 1,043.6 ± 375; p < 0.001). Patients with higher creatinine levels prior to PCI had a higher rate of CIN development after procedure. Interestingly, age, left ventricular ejection fraction, and diabetes mellitus independently predicted CIN.

Conclusion

Intensive hydration administration appears to be an effective and cost-effective method in CTO-PCI patients, especially in patients without left ventricular function failure.

Adenosine antagonists for prevention of contrast-induced nephropathy: A meta-analysis of randomized controlled trials with trial sequential analysis

Contrast-induced nephropathy (CIN) is caused by intravascular administration of contrast agent. The efficacy of adenosine antagonists (AAs) in preventing CIN remains controversial, and its elucidation was the objective of the present meta-analysis. A trial sequential analysis (TSA) to assess the reliability of the pooled results was also performed. The Medline, Embase, Web of Science and Cochrane databases were searched to retrieve all published randomized controlled trials (RCTs) comparing AAs with controls in preventing CIN. Heterogeneity, publication bias and quality of studies were assessed. Sensitivity, cumulative and subgroup analyses were also performed. The risk of random errors was evaluated by TSA. A total of 17 trials with 1,483 subjects were included. Pooled results indicated that AAs significantly reduced the incidence of CIN [risk ratio, 0.53; 95% confidence interval (CI), 0.29-0.95; P=0.034] and the serum creatinine (SCr) level after contrast media (CM) administration (standardized mean difference, -0.24; 95% CI, -0.44 to -0.04; P=0.019). Meta-regression did not identify any significant source of heterogeneity. In the subgroup analyses, AAs tended to exhibit a greater prevention efficacy in trials with sample sizes of ≥70, baseline SCr of <1.5 mg/dl and low study quality. TSA on the incidence of CIN indicated that the required information size determined as n=1,778 was not reached, and that the cumulative Z-curve did not cross the TSA boundary. In conclusion, the present meta-analysis of data from current RCTs suggested that AAs reduce the incidence of CIN and the SCr levels after CM administration. However, TSA showed that the risk of having a false-positive result was greater than 5% in the meta-analysis of the incidence of CIN, indicating that more evidence is required to ensure the benefit of AAs in preventing CIN.

Prophylactic Intravenous Hydration to Protect Renal Function From Intravascular Iodinated Contrast Material (AMACING): Long-term Results of a Prospective, Randomised, Controlled Trial

BACKGROUND

The aim of A MAastricht Contrast-Induced Nephropathy Guideline (AMACING) trial was to evaluate non-inferiority of no prophylaxis compared to guideline-recommended prophylaxis in preventing contrast induced nephropathy (CIN), and to explore the effect on long-term post-contrast adverse outcomes. The current paper presents the long-term results.

METHODS

AMACING is a single-centre, randomised, parallel-group, open-label, phase 3, non-inferiority trial in patients with estimated glomerular filtration rate [eGFR] 30-59 mL/min/1.73 m2 combined with risk factors, undergoing elective procedures requiring intravenous or intra-arterial iodinated contrast material. Exclusion criteria were eGFR < 30 mL/min/1.73 m2, dialysis, no referral for prophylaxis. The outcomes dialysis, mortality, and change in renal function at 1 year post-contrast were secondary outcomes of the trial. Subgroup analyses were performed based on pre-defined stratification risk factors. AMACING is registered with ClinicalTrials.gov: NCT02106234.

FINDINGS

From 28,803 referrals, 1120 at-risk patients were identified. 660 consecutive patients agreed to participate and were randomly assigned (1:1) to no prophylaxis (n = 332) or standard prophylactic intravenous hydration (n = 328). Dialysis and mortality data were available for all patients. At 365 days post-contrast dialysis was recorded in two no prophylaxis (2/332, 0.60%), and two prophylaxis patients (2/328, 0.61%; p = 0.9909); mortality was recorded for 36/332 (10.84%) no prophylaxis, and 32/328 (9.76%) prophylaxis patients (p = 0.6490). The hazard ratio was 1.118 (no prophylaxis vs prophylaxis) for one-year risk of death (95% CI: 0.695 to 1.801, p = 0.6449). The differences in long-term changes in serum creatinine were small between groups, and gave no indication of a disadvantage for the no-prophylaxis group.

INTERPRETATION

Assuming optimal contrast administration, not giving prophylaxis to elective patients with eGFR 30-59 mL/min/1.73 m2 is safe, even in the long-term.

FUNDING

Stichting de Weijerhorst.