Biomarkers of Contrast-Induced Nephropathy:: Which Ones are Clinically Important?

Impact of atorvastatin reload on the prevention of contrast-induced nephropathy in patients on chronic statin therapy: A prospective randomized trial

BACKGROUND

This trial aimed to assess the efficacy of Atorvastatin reloading on the prevention of Contrast-induced nephropathy (CIN) in patients pre-treated with this statin and undergoing coronary catheterization.

METHODS

This was a prospective randomized controlled study including patients on chronic atorvastatin therapy. We randomly assigned the population to the Atorvastatin Reloading group (AR group), by reloading patients with 80 mg of atorvastatin one day before and three days after the coronary procedure, and the Non-Reloading group (NR group), including patients who received their usual dose without a reloading dose. The primary endpoints were the incidence of cystatin (Cys)-based CIN and Creatinine (Scr)-based CIN. The secondary endpoints consisted of the changes in renal biomarkers (Δ biomarkers) defined as the difference between the follow-up level and the baseline level.

RESULTS

Our population was assigned to the AR group (n = 56 patients) and NR group (n = 54 patients). The baseline characteristics of the 2 groups were similar. Serum creatinine (SCr)-based CIN occurred in 11.1% in the NR group, and in 8.9% in the AR group without any significant difference. Cys-based CIN occurred in 37% in the NR group and 26.8% in the AR group without any significant difference. The subgroup analysis showed that high dose reloading had significantly reduced the CYC-based CIN risk in patients with type 2 diabetes (43.5% vs 18.8%, RR = 0.43. CI 95% [0.18-0.99])). The comparison of "Δ Cystatin" and Δ eGFR between the AR and NR groups didn't show any significant difference. However, cystatin C had significantly increased between baseline and at 24 hours in the NR group (0.96 vs 1.05, p = 0.001), but not in the AR group (0.94 vs 1.03, p = 0.206).

CONCLUSIONS

Our study did not find a benefit of systematic atorvastatin reloading in patients on chronic atorvastatin therapy in preventing CIN. However, it suggested that this strategy could reduce the risk of CyC-based CIN in diabetic type 2 patients.

The Pathophysiology and the Management of Radiocontrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is an impairment of renal function that occurs after the administration of an iodinated contrast medium (CM). Kidney dysfunction in CIN is considered transient and reversible in most cases. However, it is the third most common cause of hospital-acquired acute kidney injury and is associated with increased morbidity and mortality, especially in high-risk patients. Diagnostic and interventional procedures that require intravascular CM are being used with increasing frequency, especially among the elderly, who can be particularly susceptible to CIN due to multiple comorbidities. Therefore, identifying the exact mechanisms of CIN and its associated risk factors is crucial not only to provide optimal preventive management for at-risk patients, but also to increase the feasibility of diagnostic and interventional procedure that use CM. CM induces kidney injury by impairing renal hemodynamics and increasing the generation of reactive oxygen species, in addition to direct cytotoxicity. Periprocedural hydration is the most widely accepted preventive strategy to date. Here, we review the latest research results on the pathophysiology and management of CIN.

The Perspectives of Biomarkers in Predicting the Survival of the Renal Graft

Kidney transplantation (KT) is currently the elective approach for patients with end-stage renal disease. Although it is a safe choice for these patients, the early complications can lead to graft dysfunction. One of the most redoubtable complications is delayed graft function (DGF), having no specific treatment. The effects of DGF on the graft survival are large enough to justify the formulation of specific biological protocols. Therefore, discovering biomarkers of acute impairment in renal transplanted patients is required. Creatinine is a poor marker to establish the kidney injury. Estimated glomerular filtration rate together with creatinine is ready to approximately measure the kidney function. Different serum and urine proteins are being studied as possible predictive biomarkers for delayed graft function. This review will concentrate on recent and existing research which provide insight concerning the contribution of some molecules for the estimation and evaluation of graft function after kidney transplantation. Further studies examining various aspects of DGF after KT are urgently needed to address a hitherto less-known clinical question.

The relationship between pre-procedural elevated arterial lactate and contrast-induced nephropathy following primary percutaneous coronary intervention

Background

Risk stratification has been one of the main steps in preventing contrast-induced nephropathy (CIN), which is a common complication after percutaneous coronary intervention (PCI). Elevated arterial lactate is a biomarker indicating severe disease condition and post-intervention complications. The relationship between lactate and CIN has not been established. This study is performed to investigate the relationship between elevated arterial lactate level and contrast-induced nephropathy (CIN).

Methods

Patients diagnosed with ST-segment elevated myocardial infarction (STEMI) were prospectively enrolled, with lactate measured within 0.5–1 hours before primary percutaneous coronary intervention (PCI). Patients with cardiopulmonary resuscitation, any forms of severe anaerobic condition, or end-stage renal disease undergoing dialysis were excluded. CIN was defined as an increase in serum creatinine ≥0.5 mg/dL or 25% within 72 hours after PCI. The Mehran Risk Score (MRS) is widely regarded as a classic risk model for CIN and the risk factors of MRS were applied in our multivariate regression analysis.

Results

Of the 227 enrolled patients, 47 (20.7%) developed CIN according to the definition. The mean lactate level was higher in the CIN group than in the non-CIN group (2.68±2.27 vs. 1.74±1.94, P<0.001). The arterial lactate level ≥2.0 mmol/L had 57.5% sensitivity and 75.6% specificity in predicting CIN. The performance of the lactate level in discriminating CIN was similar to that of the MRS (AUC_lac =0.707 vs. AUC_MRS =0.697, P=0.86). After adjusting for other risk factors, lactate ≥2.0 mmol/L still significantly predicted CIN (odds ratio =3.77, 95% CI, 1.77–7.99, P=0.001).

Conclusions

An arterial lactate level of ≥2.0 mmol/L is associated with CIN in STEMI patients after primary PCI.