**4.1 Preexisting renal disease**

Preexisting renal disease with an elevated basal level of serum creatinine is the most important risk factor for the occurrence of CIN. The incidence of CIN in patients with preexisting chronic kidney disease is extremely high, ranging from


**121**

*Contrast-Induced Nephropathy*

*DOI: http://dx.doi.org/10.5772/intechopen.90457*

tion rate (eGFR) of 60 mL/min/1.73 m2

factors of elevated CIN risk in elderly.

risk assessment [25].

**4.2 Diabetes mellitus**

impairment [27].

**4.3 Age**

**4.4 Gender**

0.05) [29].

14.8 to 55% [20]. As depicted in a study, despite pre-procedure adequate hydration and the use of nonionic CM, CIN happened in one-third of the 439 patients who underwent PCI and had basal creatinine level more than or equal to 1.8 mg/dl [22]. The higher the basal serum creatinine level, the greater the risk of developing CIN. As seen in a study, if basal serum creatinine level is estimated to be ≤1.2 mg/dl, the risk of development of CIN is just 2% [23]. In patients with values of creatinine in the range of 1.4–1.9 mg/dl, the risk of CIN in comparison with that in the previous group increases fivefold (10.4%) [23]. Regarding patients with baseline serum creatinine more than or equal to 2.0 mg/dl, 62% of them developed CIN [24]. However, baseline creatinine is not reliable enough for the determination of patients who are at risk for CIN. This arises due to the variation on the basis of gender, age, and muscular mass. For instance, a normal serum creatinine value probably correlates with a moderate decrease in renal function. In order to properly evaluate renal function, assessment of creatinine clearance should be done. The direct measurement of the creatinine clearance is not practical to be done; however, its estimation based on the Cockcroft-Gault formula or Modification of Diet in Renal Disease equation can be easily performed. Multiple studies have proven that an estimated glomerular filtra-

high risk for the development of CIN. Thus, the estimation of GFR is crucial for CIN

Diabetic patients represent a very important proportion of those undergoing contrast exposures due not only to the prevalence of diabetes in the general population but also the ability of the disease to cause a wide spectrum of diseases which require radiological procedures using contrast media. The incidence of CIN in diabetic patients varies from 5.7 to 29.4% [26]. Importantly, in diabetic patients with preserved renal function and without other risk factors, the rates of CIN are approximately equal to those of a nondiabetic population [27], while clinically important CIN mostly happens in a group of diabetics with preexisting renal

Several studies showed that older age is an independent predictor of CIN [28]. The reasons for higher risk are multifactorial, which encompasses age-related changes in renal function including decreased glomerular filtration rate, renal concentration ability, and tubular secretion. The presence of multi-vessel coronary artery disease, mandating complex more prolonged PCI, combined with more difficult vascular access that results from tortuosity and calcification of the vessels that frequently requires a greater amount of contrast, and therefore represent additional

Ovarian hormones can have an influence upon the renin-angiotensin system as well as the renal blood flow. In a retrospective study of 8628 patients who underwent PCI, female sex presented an independent risk predictor of CIN (OR = 1.4, p < 0.0001). One-year analyses of outcomes by gender demonstrated a higher mortality rate when compared to males in a cohort of CIN patients (14 vs 10%, p =

is a cutoff value for considering patients at

**Table 1.**

*Common risk factors for contrast nephropathy after coronary angiography [20].*

#### *Contrast-Induced Nephropathy DOI: http://dx.doi.org/10.5772/intechopen.90457*

*New Insight into Cerebrovascular Diseases - An Updated Comprehensive Review*

CIN is one of the most significant causes of hospital-acquired acute kidney injury (AKI) [8] and presents about 12% of the cases [9]. It represents the third most common cause after renal hypoperfusion (42%) and postoperative renal injury (18%). The reported incidence of CIN following percutaneous coronary intervention (PCI) lies between 0 and 24%. This depends on the associated risk factors, with the greatest incidence being reported after emergency PCI [10, 11]. A meta-analysis which included 40 studies showed a 6% incidence of CIN following contrast-enhanced computed tomography (CT) [12], 9% following peripheral angiography [3], and 4% following intravenous pyelography [13]. The incidence of CIN is low in patients with normal renal function (0–5%) [14]. However, there is an incidence of 12–27% in patients having preexisting renal impairment [15]. Moreover, in one study, an incidence as high as 50% was found in patients with diabetic nephropathy undergoing coronary angiography despite the use of low-osmolar CM (LOCM) and adequate hydration. Also, up to 15% of them needed dialysis [16]. Development of CIN is associated with a longer duration of hospital stay and an increased morbidity and mortality, in addition to more costs [1, 17]. Elevation of post-PCI serum creatinine may have prognostic significance regardless of the initial kidney functions. In fact, a slight elevation in serum creatinine (25–35 μmol/l) is associated with an increase in 30-day mortality [18]. Furthermore, post-PCI serum creatinine elevation has been reported to be linked to higher 1-year mortality than

Mild, transient decreases in GFR occur after contrast administration in nearly all patients. The development of clinically significant acute renal failure depends very much upon the presence or absence of certain risk factors (**Table 1**); factors that increase the incidence of development of CIN are linked to the patient's comorbid conditions, the procedure to be performed, and the nature of the contrast agents [21].

Preexisting renal disease with an elevated basal level of serum creatinine is the most important risk factor for the occurrence of CIN. The incidence of CIN in patients with preexisting chronic kidney disease is extremely high, ranging from

**Modifiable risk factors**

Dehydration

Anemia

Circulatory collapse

Osmolality and ionic content of contrast medium Volume of contrast medium administered Repeated exposure to contrast medium

Myocardial infarction less than 24 h before angiography

**3. Epidemiology**

periprocedural myocardial necrosis [19].

**4. Risk factors**

**Degree of risk**

Minor Age

**4.1 Preexisting renal disease**

**Nonmodifiable risk** 

Reduced ejection fraction Congestive heart failure Hypertension

*Common risk factors for contrast nephropathy after coronary angiography [20].*

**factors**

Major Preexisting renal disease Diabetes mellitus

Gender

**120**

**Table 1.**

14.8 to 55% [20]. As depicted in a study, despite pre-procedure adequate hydration and the use of nonionic CM, CIN happened in one-third of the 439 patients who underwent PCI and had basal creatinine level more than or equal to 1.8 mg/dl [22]. The higher the basal serum creatinine level, the greater the risk of developing CIN. As seen in a study, if basal serum creatinine level is estimated to be ≤1.2 mg/dl, the risk of development of CIN is just 2% [23]. In patients with values of creatinine in the range of 1.4–1.9 mg/dl, the risk of CIN in comparison with that in the previous group increases fivefold (10.4%) [23]. Regarding patients with baseline serum creatinine more than or equal to 2.0 mg/dl, 62% of them developed CIN [24]. However, baseline creatinine is not reliable enough for the determination of patients who are at risk for CIN. This arises due to the variation on the basis of gender, age, and muscular mass. For instance, a normal serum creatinine value probably correlates with a moderate decrease in renal function. In order to properly evaluate renal function, assessment of creatinine clearance should be done. The direct measurement of the creatinine clearance is not practical to be done; however, its estimation based on the Cockcroft-Gault formula or Modification of Diet in Renal Disease equation can be easily performed. Multiple studies have proven that an estimated glomerular filtration rate (eGFR) of 60 mL/min/1.73 m2 is a cutoff value for considering patients at high risk for the development of CIN. Thus, the estimation of GFR is crucial for CIN risk assessment [25].
