Risk Factors For Contrast-induced Nephropathy in Patients With Chronic Kidney Disease

Contrast-induced nephropathy (CIN) is an important complication in the application of iodinated contrast agents and an important part of iatrogenic acute kidney injury. Due to the increasing number of patients undergoing angiography and interventional procedures, more patients will be treated with iodine contrast agents; at the same time, the incidence of chronic kidney disease (CKD), the most important risk factor for CIN, is worldwide. has reached about 10%. Therefore, CIN has become an important concern for radiologists, cardiologists, and nephrologists.

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Well-established risk factors for CIN

original CKD

Based on multiple data, it was found that the estimated glomerular filtration rate (eGFR) <60ml/(min·1.73m2) had a significantly higher risk of CIN. Specifically, CKD stages 3-5 were the risk factors for CIN. The incidence of CIN in CKD patients was positively correlated with the degree of renal impairment before angiography. CIN is less common in patients with normal renal function. Since serum creatinine alone is not sufficient to accurately assess renal function, eGFR values should be calculated in all patients before using iodinated contrast agents (the simplified MDRD formula is recommended).

Diabetes with CKD

Among all the risk factors for CIN, diabetes complicated with CKD is the most important risk factor. The risk of CIN in diabetic patients with CKD is higher than that in CKD patients without diabetes with the same level of renal function. It has been reported that the incidence of CIN after receiving contrast agents is almost 100% in patients with a history of diabetes of more than 10 years, and age >50 years, combined with vascular disease and renal dysfunction.

Advanced age (age ≥ 70 years old)

It has been confirmed that the incidence of CIN increases with age, which may be related to the decline of renal function. However, other studies have found that age is an independent predictor of CIN. With age, vascular stiffness increases and endothelial function is damaged, resulting in decreased vasodilation and pluripotent stem cell's ability to repair blood vessels, resulting in an increased risk of CIN in the elderly and a decline in the rapid repair function of the kidneys.

heart failure

Cardiac function grades III to IV or decreased left ventricular ejection fraction (EF<40%) are independent risk factors for CIN.

Perioperative hemodynamic instability

Several large studies in patients undergoing cardiac intervention (PCI) have shown that CIN is associated with hemodynamic instability, such as perioperative hypotension and the use of an intra-aortic balloon pump (IABP). Hypotension increases the likelihood of renal ischemia and is therefore a significant risk factor for AKI in acutely ill patients. Possible mechanisms of CIN with IABP use include: IABP use is a marker of hemodynamic instability and a marker of severe atherosclerotic disease. The use of IABP may also dislodge atherosclerotic thrombus from aortic plaques, impairing renal function.

Concomitant use of nephrotoxic drugs

Concomitant use of nephrotoxic drugs (including diuretics, non-steroidal anti-inflammatory drugs, cyclooxygenase 2 inhibitors, aminoglycoside antibiotics, amphotericin B, etc.) patients tends to have an increased risk of developing CIN.

Contrast factor

Contrast dose In at-risk patients with contrast media greater than 100 ml, the incidence of CIN will be higher, and there is no threshold dose for CIN, and CIN may occur even when the volume of contrast media is <30 ml.

The types of contrast media have been identified in patients with a high risk of CIN, hypotonic (800m0sm/L, in fact, the osmotic pressure is significantly higher than the plasma osmotic pressure but lower than the hypertonic contrast media with an osmotic pressure of 1200m0sm/L) and isotonic (300m0sm/L) Non-ionic contrast agents and ionic contrast agents with higher osmolarity are safe, and hypertonic ionic contrast agents should be avoided in high-risk patients, but it is still controversial whether isotonic contrast agents are superior to hypotonic contrast agents. In addition, the risk of CIN is higher with intra-arterial contrast than with intravenous contrast. For patients with chronic renal insufficiency [eGFR<60ml/(min·1.73m2)] who are going to use contrast media in arteries, isotonic contrast media should be selected, and for patients with chronic renal insufficiency who are planning to use contrast media intravenously, it is recommended to use such Osmotic or hypotonic contrast media.

In addition, the short interval between two contrast media applications can increase the risk of CIN. Patients without CIN risk factors should be separated by 48 hours, and patients with existing CKD or diabetes should be separated by 72 hours after intra-arterial administration. Drugs that are much higher also increase the risk of CIN.

Possible risk factors for CIN

diabetes  

The vast majority of studies have shown that diabetes is a predictor of CIN, but it is unclear whether the risk of CIN is increased in diabetic patients with eGFR>60ml/(min·1.73m2). Diabetic patients with a long course of the disease have a high incidence of chronic complications such as hypertension, ischemic nephropathy, multi-vessel coronary artery disease, and peripheral vascular disease. should be classified as a high-risk group for CIN.

Use angiotensin-converting enzyme inhibitor (ACEI) or angiotensin III receptor blocker (ARB)

Regarding the effect of ACEI or ARB on CIN, the results of multiple studies are not consistent. It has been reported that the use of ACEI in patients with existing renal insufficiency increases the risk of CIN, but Dangash et al believe that preoperative use of ACEI in patients with CKD can reduce the risk of CIN. Considering that the use of ACEI or ARB is often an important drug in the treatment of patients with CKD and diabetes, and the use of these drugs may increase the basal serum creatinine by 10% to 25%, it should be considered when evaluating renal function before and after angiography.

Other possible or controversial risk factors for CIN

Including hypertension, hypoalbuminemia, hypercholesterolemia, emergency angiography, anemia, sepsis, rhabdomyolysis, hyponatremia, pulmonary edema, microalbuminuria, bypass graft intervention, renal surgery history, polyarteritis nodosa, coronary multivessel disease, AIDS, peripheral vascular disease, renal artery stenosis, acute myocardial infarction, postprandial blood glucose impairment, hypertriglyceridemia, hyperuricemia, multiple myeloma, Women, liver cirrhosis, kidney transplantation, etc.

Score high-risk patients to predict the occurrence of CIN

Mehran et al. scored according to various risk factors for CIN. After the scores were added, the higher the total score, the higher the incidence of CIN and the greater the risk of requiring dialysis (Table 1). This method is intuitive and simple and provides a practical method for CIN risk assessment, which is worth learning from.

In conclusion, CKD patients are often combined with other diseases or high-risk factors, and their risk of CIN is higher after the use of contrast agents. In addition to an accurate assessment of renal function before surgery, the corresponding risk factors should be corrected as much as possible, and various preventive measures should be taken to minimize the occurrence of CIN.

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