Investigating the volume status before contrast nephropathy studies

Inferior vena cava assessment can predict contrast-induced nephropathy in patients undergoing cardiac catheterization: A single-center prospective study

BACKGROUND

Contrast-induced nephropathy (CIN) following cardiac catheterization remains a considerable clinic challenge. Volume status is very important in the development of CIN. It can be assessed noninvasively by measuring inferior vena cava (IVC) diameters. The aim of this study was to assess whether IVC can be used for prediction of CIN in patient undergoing cardiac catheterization.

METHODS

A total of 269 patients undergoing cardiac catheterization were prospectively enrolled in this study. IVC inspiratory and expiratory diameters were measured by transthoracic echocardiography. Caval index was calculated as the percentage decrease in the IVC diameter during respiration. CIN was defined as a ≥0.5 mg/dL and/or a ≥25% increase in serum creatinine within 72 hour post-procedure.

RESULTS

Contrast-induced nephropathy developed in 46 (17.1%) patients after cardiac catheterization. Caval index was significantly higher in patients with CIN than in patients without CIN (47% [40-64] vs 35% [26-50], P < 0.001). In addition, the used contrast volume (145 [90-217] vs 70 [60-100], P < 0.001) and the frequency of percutaneous coronary intervention (50% vs 17.9%, P < 0.001) were significantly higher in patients with CIN than in patients without CIN. In receiver operating characteristic (ROC) curve analysis, caval index ≥ 41% predicted CIN with a specificity of 69% and sensitivity of 72%. Multivariate analysis indicated that caval index ≥ 41% was an independent predictor of post-procedural CIN development (OR: 3.367, 95% CI: 1.574-7.203, P = 0.002).

CONCLUSIONS

Caval index, a simple and noninvasive echocardiographic marker, is an independent predictor of post-procedural CIN development in patients undergoing cardiac catheterization.

Risk Factors and Therapy Strategies for Contrast-Induced Nephropathy

Contrast-induced nephropathy (CIN) is associated with increased morbidity and mortality, as well as increased costs for medical care, particularly in patients with diabetes mellitus and chronic renal failure. A key step to safer CIN is to identify patients at risk and applying proven preventive interventions. Extracellular volume expansion, minimizing the dose of contrast media, using low-osmolar non-ionic contrast media, stopping the intake of nephrotoxic drugs, and avoiding short intervals between procedures have all been shown to be effective in reducing CIN. The aim of the present review is to summarize the knowledge about the risk factors and prophylactic treatments of CIN.

Interactions between serum creatinine, volume status, N-acetylcysteine, and contrast-induced nephropathy

Contrast-induced nephropathy is reported to be the third leading cause of acute renal failure. The development of contrast-induced nephropathy is associated with prolonged hospitalization, the potential need for renal replacement therapy, and increased mortality. N-acetylcysteine is commonly used for the prevention of contrast-induced nephropathy despite inconsistent results from numerous clinical trials and meta-analyses. The advantage of N-acetylcysteine in most studies was based on a decrease in the serum creatinine concentration and a decrease in oxidative stress. N-acetylcysteine itself can directly lower serum creatinine concentration without improving renal function, and hypovolemia can affect the oxidative stress. In most of the N-acetylcysteine studies, there are a lack of volume status and secondary end points. The value of N-acetylcysteine for the prevention of contrast-induced nephropathy seems questionable. The interactions between serum creatinine, N-Acetylcysteine, volume status, and the development of contrast-induced nephropathy were discussed in this letter.

Risk factors for contrast-induced nephropathy

An increasing number of diagnostic imaging and interventional procedures require the use of radiographic contrast agents which has led to a parallel increase in the incidence of contrast-induced nephropathy (CIN). CIN is a serious clinical problem associated with increased morbidity and mortality, particularly in patients with chronic renal failure (see the Case Report). A key step to minimize CIN is to identify patients at risk of CIN. The aim of the present review was to summarize the knowledge about the risk factors of CIN, including the review of ultimate clinical research and developments.