Contrast-induced kidney injury

Impact of Contrast-Associated Acute Kidney Injury on One-Year Outcomes in Very Elderly STEMI Patients: Insights From a Multicenter Registry in Northern Italy

Data about contrast-associated acute kidney injury (CA-AKI) in oldest old (age ≥85 years) ST-elevation myocardial infarction (STEMI) patients are scarce. We evaluated the incidence and the 1-year prognostic impact of CA-AKI in this population. Patients were included in a multicenter real-world registry, and CA-AKI was defined according to KDIGO (Kidney Disease Improving Global Outcomes) criteria. Major adverse cardiac and cerebrovascular events (MACCEs) were defined as the composite of all-cause death, stroke, unplanned coronary revascularization, and heart failure hospitalization. The primary outcome was the incidence and impact of CA-AKI on MACCEs at 1 year follow-up. Out of 461 STEMI patients (mean age 88.6 ± 2.9 years), 102 (22.1%) patients developed CA-AKI. Chronic kidney disease was the strongest predictor of CA-AKI (odds ratio [OR]: 4.52, 95% CI: 2.81-7.30, P < .01). The CA-AKI cohort showed a higher risk of MACCEs (adjusted HR: 1.75, 95% CI: 1.13-2.71, P = .01), driven mainly by all-cause death (adjusted hazard ratio [HR]: 2.39, 95% CI: 1.41-4.07, P = .01) and followed by heart failure hospitalization (adjusted HR: 2.01, 95% CI: 1.08-3.76, P = .01). Among oldest old STEMI, CA-AKI was frequent and associated with a higher incidence of MACCEs at 1-year follow-up.

Cost to Medicare of acute kidney injury in percutaneous coronary intervention

BACKGROUND

Acute kidney injury (AKI), including contrast-induced AKI (CI-AKI), is an important complication of percutaneous coronary intervention (PCI), resulting in short- and long-term adverse clinical outcomes. While prior research has reported an increased cost burden to hospitals from CI-AKI, the incremental cost to payers remains unknown. Understanding this incremental cost may inform decisions and even policy in the future. The objective of this study was to estimate the short- and long-term cost to Medicare of AKI overall, and specifically CI-AKI, in PCI.

METHODS

Patients undergoing inpatient PCI between January 2017 and June 2020 were selected from Medicare 100% fee-for-service data. Baseline clinical characteristics, PCI lesion/procedural characteristics, and AKI/CI-AKI during the PCI admission, were identified from diagnosis and procedure codes. Poisson regression, generalized linear modelling, and longitudinal mixed effects modelling, in full and propensity-matched cohorts, were used to compare PCI admission length of stay (LOS) and cost (Medicare paid amount inflated to 2022 US$), as well as total costs during 1-year following PCI, between AKI and non-AKI patients.

RESULTS

The study cohort included 509,039 patients, of whom 104,033 (20.4%) were diagnosed with AKI and 9,691 (1.9%) with CI-AKI. In the full cohort, AKI was associated with +4.12 (95% confidence interval = 4.10, 4.15) days index PCI admission LOS, +$11,313 ($11,093, $11,534) index admission costs, and +$14,800 ($14,359, $15,241) total 1-year costs. CI-AKI was associated with +3.03 (2.97, 3.08) days LOS, +$6,566 ($6,148, $6,984) index admission costs, and +$13,381 ($12,118, $14,644) cumulative 1-year costs (all results are adjusted for baseline characteristics). Results from the propensity-matched analyses were similar.

CONCLUSIONS

AKI, and specifically CI-AKI, during PCI is associated with significantly longer PCI admission LOS, PCI admission costs, and long-terms costs.

NGAL as Biomarker of Clinical and Subclinical Damage of Kidney Function after Coronary Angiography

Contrast-induced acute kidney injury (CI-AKI) is a serious complication after angiographic examinations in cardiology. Diagnosis may be delayed based on standard serum creatinine, and subclinical forms of kidney damage may not be detected at all. In our study, we investigate the clinical use in these directions of a “damage”-type biomarker—neutrophil gelatinase-associated lipocalin (NGAL). Among patients with a high-risk profile undergoing scheduled coronary angiography and/or angioplasty, plasma NGAL was determined at baseline and at 4th and 24th h after contrast administration. In the CI-AKI group, NGAL increased significantly at the 4th hour (Me 109.3 (IQR 92.1–148.7) ng/mL versus 97.6 (IQR 69.4–127.0) ng/mL, p = 0.006) and at the 24th hour (Me 131.0 (IQR 81.1–240.8) ng/mL, p = 0.008). In patients with subclinical CI-AKI, NGAL also increased significantly at the 4th hour (Me 94.0 (IQR 75.5–148.2) ng/mL, p = 0.002) and reached levels close to those in patients with CI-AKI. Unlike the new biomarker, however, serum creatinine did not change significantly in this group. The diagnostic power of NGAL is extremely good—AUC 0.847 (95% CI: 0.677–1.000; p = 0.001) in CI-AKI and AUC 0.731 (95% CI: 0.539–0.924; p = 0.024) in subclinical CI-AKI. NGAL may be a reliable biomarker for the early diagnosis of clinical and subclinical forms of renal injury after contrast angiographic studies.

Evaluation of Crocin Effect on Contrast-Induced Nephropathy Following Coronary Angiography or Angioplasty: A Randomized Controlled Trial

Contrast-induced nephropathy (CIN) is the third cause of hospital-acquired acute kidney injury. The CIN prophylactic strategies adopted to date, although not highly efficient, are mostly based on antioxidant activity and hydration therapy. This study was designed and conducted to evaluate crocin’s efficacy in the prevention of CIN in chronic kidney disease (CKD) patients undergoing coronary angiography/angioplasty. In this randomized clinical trial, a total of 110 eligible CKD stage 3 patients requiring contrast agent administration for coronary angiography/angioplasty were enrolled and randomly assigned to either crocin (n = 57) or control (n = 53) group. The patients in both groups received standard hydration therapy; nevertheless, in the crocin group, the patients were also orally administered three consecutive oral doses of 30 mg crocin tablets 1 day before up to 1 day after contrast media (CM) exposure. The primary endpoint was CIN incidence defined as an increase in serum creatinine (SrCr) level by ≥ 0.3 mg/dL or any change in urinary neutrophil gelatinase-associated lipocalin (NGAL) from the baseline within 48 hours of CM exposure. During 4 months, 130 patients were recruited. The mean age of the patients was 65.62 ± 9.05 years, and the majority of them were male (64.54%). The SrCr in the crocin group did not significantly increase within 48 hours of angiography/angioplasty. The changes in the urinary NGAL level were not significant in both groups. The CIN incidence was significantly lower in the crocin group than in the control group (1.75% and 13.2%; P = 0.028). Crocin administration plays an important nephron-protective role in the prevention of CIN.

Contrast Associated Acute Kidney Injury and Mortality in Older Adults with Acute Coronary Syndrome: A Pooled Analysis of the FRASER and HULK Studies

Whether contrast-associated acute kidney injury (CA-AKI) is only a bystander or a risk factor for mortality in older patients undergoing percutaneous coronary intervention (PCI) is not well understood. Data from FRASER (NCT02386124) and HULK (NCT03021044) studies have been analysed. All patients enrolled underwent coronary angiography. The occurrence of CA-AKI was defined based on KDIGO criteria. The primary outcome of the study was to test the relation between CA-AKI and 3-month mortality. Overall, 870 older ACS adults were included in the analysis (mean age 78 ± 5 years; 28% females). CA-AKI occurred in 136 (16%) patients. At 3 months, 13 (9.6%) patients with CA-AKI died as compared with 13 (1.8%) without it (p < 0.001). At multivariable analysis, CA-AKI emerged as independent predictor of 3-month mortality (HR 3.51, 95%CI 1.05–7.01). After 3 months, renal function returned to the baseline value in 78 (63%) with CA-AKI. Those without recovered renal function (n = 45, 37%) showed an increased risk of mortality as compared to recovered renal function and no CA-AKI subgroups (HR 2.01, 95%CI 1.55–2.59, p = 0.009 and HR 2.71, 95%CI 1.45–5.89, p < 0.001, respectively). In conclusion, CA-AKI occurs in a not negligible portion of older MI patients undergoing invasive strategy and it is associated with short-term mortality.

Measuring the Variation in the Prevention and Treatment of CI-AKI Among Interventional Cardiologists

Contrast-induced acute kidney injury (CI-AKI) occurs in up to 10% of cardiac catheterizations and coronary interventions, resulting in increased morbidity, mortality, and cost. One main reason for these complications and costs is under-recognition of CI-AKI risk and under-treatment of patients with impaired renal status. 157 interventional cardiologists each cared for three simulated patients with common conditions requiring intravascular contrast media in three typical settings: pre-procedurally, during the procedure, and post-procedure. We evaluated their ability to assess the risk of developing CI-AKI, make the diagnosis, and treat CI-AKI, including proper volume expansion and withholding nephrotoxic medications. Overall, the quality-of-care scores averaged 46.0% ± 10.5, varying between 18% to 78%. The diagnostic scores for accurately assessing risk of CI-AKI were low at 57.1% ± 21.2% and the accuracy of diagnosis pre-existing chronic kidney disease was 50.2%. Poor diagnostic accuracy led to poor treatment: proper volume expansion done in only 30.7% of cases, in-hospital repeat creatinine evaluation performed in 32.1%, and avoiding nephrotoxic medications occurred in 14.2%. While volume expansion was relatively similar across the three settings (P = 0.287), the cardiologists were less likely to discontinue nephrotoxic medications in pre-procedurally (9.7%) compared to the other settings (27.0%), and to order in-hospital creatinine testing in peri-procedurally (18.8%) compared to post-procedure (57.8%) (P < 0.05 for both). The overall care of patients at risk for contrast-induced acute kidney injury varied widely and showed room for improvement. Improving care for this condition will require greater awareness by cardiologists and better diagnostic tools to guide them.

Practical guide to prevention of contrast-induced acute kidney injury after percutaneous coronary intervention

Contrast-induced acute kidney injury (CI-AKI) represents a common but serious complication of percutaneous coronary interventions (PCI)-and in general of all those examinations requiring iodinated contrast injection-which affects not only renal function but also long-term prognosis. While several prophylactic approaches were designed in order to prevent CI-AKI, most failed to demonstrate clear benefits in randomized trials, and their implementation is therefore discouraged in clinical practice. The most notorious examples include pre-procedural bicarbonate or N-acetylcysteine, and preprocedural withdrawal of ACE inhibitors/Angiotensin receptor blockers. Those strategies that were instead demonstrated effective include the appropriate use of preprocedural hydration, reduction in contrast volume utilization, adoption of techniques for zero- or ultra-low-contrast procedures, and pharmacological treatments with statins. In this brief review, we summarize the main preventive strategies into brief and pragmatic recommendations designed to improve everyday clinical practice.

Contrast Induced Acute Kidney Injury and its Impact on Mid-Term Kidney Function, Cardiovascular Events and Mortality

The existence and clinical relevance of contrast induced acute kidney injury (CI-AKI) is still heavily debated and angiographic procedures are often withheld in fear of CI-AKI, especially in CKD-patients. We investigated the incidence of CI-AKI in cardiovascular high risk patients undergoing intra-arterial angiography and its impact on mid-term kidney function, cardiovascular events and mortality. We conducted a prospective observational trial on patients undergoing planned intra-arterial angiographic procedures. All subjects received standardized intravenous hydration prior to contrast application. CI-AKI was defined according to a ≥25% increase of creatinine from baseline to either 24hrs or 48hrs after angiography. Plasma creatinine and eGFR were recorded from the institutional medical record system one and three months after hospital discharge. Patients were followed up for two years to investigate the long term effects of CI-AKI on cardiovascular events and mortality. We studied 706 (317 female) patients with a mean eGFR of 52.0 ± 15 ml·min⁻¹·1.73 m⁻². The incidence of CI-AKI was 10.2% (72 patients). In 94 (13.3%) patients serum creatinine decreased ≥25% either 24 or 48 hours after angiography. Patients with CI-AKI had a lower creatinine and a higher eGFR at baseline, but no other independent predictors of CI-AKI could be identified. Kidney function was not different between both groups one and three months after discharge. After a two year follow up the overall incidence of cardiovascular events was 56.5% in the CI-AKI group and 58.8% in the Non CI-AKI group (p = 0.8), the incidence of myocardial infarctions, however, was higher in CI-AKI-patients. Overall survival was also not different between patients with CI-AKI (88.6%) and without CI-AKI (84.7%, p = 0.48). The occurrence of CI-AKI did not have any negative impact on mid-term kidney function, the incidence of cardiovascular events and mortality. Considerable fluctuations of serum creatinine interfere with the presumed diagnosis of CI-AKI. Necessary angiographic procedures should not be withheld in fear of CI-AKI.

Long-term risk of adverse outcomes after acute kidney injury: a systematic review and meta-analysis of cohort studies using consensus definitions of exposure

Reliable estimates of the long-term outcomes of acute kidney injury (AKI) are needed to inform clinical practice and guide allocation of health care resources. This systematic review and meta-analysis aimed to quantify the association between AKI and chronic kidney disease (CKD), end-stage kidney disease (ESKD), and death. Systematic searches were performed through EMBASE, MEDLINE, and grey literature sources to identify cohort studies in hospitalized adults that used standardized definitions for AKI, included a non-exposed comparator, and followed patients for at least 1 year. Risk of bias was assessed by the Newcastle-Ottawa Scale. Random effects meta-analyses were performed to pool risk estimates; subgroup, sensitivity, and meta-regression analyses were used to investigate heterogeneity. Of 4973 citations, 82 studies (comprising 2,017,437 participants) were eligible for inclusion. Common sources of bias included incomplete reporting of outcome data, missing biochemical values, and inadequate adjustment for confounders. Individuals with AKI were at increased risk of new or progressive CKD (HR 2.67, 95% CI 1.99-3.58; 17.76 versus 7.59 cases per 100 person-years), ESKD (HR 4.81, 95% CI 3.04-7.62; 0.47 versus 0.08 cases per 100 person-years), and death (HR 1.80, 95% CI 1.61-2.02; 13.19 versus 7.26 deaths per 100 person-years). A gradient of risk across increasing AKI stages was demonstrated for all outcomes. For mortality, the magnitude of risk was also modified by clinical setting, baseline kidney function, diabetes, and coronary heart disease. These findings establish the poor long-term outcomes of AKI while highlighting the importance of injury severity and clinical setting in the estimation of risk.