Renal Effects of Nonionic Contrast Media after Cardioangiography

A prospective double-blind randomized cardioangiographic study with iopentol and iohexol was performed in 60 patients. Glomerular filtration rate (GFR) was assessed by serum values of creatinine and β2-microglobulin (β2-MG), estimated creatinine clearance (CCr) according to Cockroft & Gault's formula, and 24 hour CCr. The urinary excretion of albumin, β2-MG, and of the renal tubular enzymes alkaline phosphatase (ALP) and N-acetyl-β-glucosaminidase (NAG) was also measured. Contrary to what has been found after i.v. injections, GFR was reduced by both nonionic contrast media. Serum creatinine (S-Cr) was increased by more than 25% in 6 patients, 3 in each group. CCr was more sensitive than S-Cr and S-β2-MG, but this method is less precise because of risk of urine sampling errors. Estimated CCr gave no additional information to S-Cr. The urinary excretion of NAG and ALP was increased. No clinically significant differences between iopentol and iohexol were detected. No correlation was found between the changes in tubular function parameters and changes in GFR. Twenty patients were on calcium channel blockers before the investigation, but this had no protective effect on the renal function parameters.

Effect of Iopentol on Renal Function and its Use for Calculation of Glomerular Filtration Rate in Children

Nineteen children received 99mTc-DTPA for renography. The next day they received a simultaneous injection of the non-ionic contrast medium iopentol for urography and another injection of 99mTc-DTPA. The glomerular filtration rate (GFR) was estimated from the plasma elimination of 99mTc-DTPA as well as iopentol. Serum concentrations of creatinine and β2-microglobulin, and urine concentrations of creatinine, β2-microglobulin, alkaline phosphatase, N-acetyl-glucosaminidase, and albumin were determined. A significant reduction (12 ± 3%) of GFR was observed after the injection of iopentol, without a subsequent rise in serum creatinine or β2-microglobulin. The urinary excretion of albumin and β2-microglobulin remained unchanged, while the excretion of alkaline phosphatase and N-acetyl-glucosaminidase was significantly increased after the urography, indicating some tubular effects of iopentol. Iopentol caused few and mild adverse events, the diagnostic yield was high, and the small changes in the renal tubular function parameters are presumed to be without clinical importance. The observed depressive effect on the GFR demands further investigations before iopentol can be recommended as a GFR-marker in children.

Renal Effects of Iopentol and Iohexol after Intravenous Injection

Renal effects of the 2 non-ionic contrast media iopentol and iohexol were investigated and compared in a double-blind, randomized parallel study where 30 patients received iopentol, and 31 patients iohexol intravenously for abdominal CT. The dosage of contrast medium (350 mg I/ml) was 700 mg I/kg body weight. Only one patient (in the iohexol group) had an increase in serum creatinine of more than 50%. Iopentol and iohexol had no effects on the mean serum values of creatinine, urea, and β2-microglobulin (β2-MG) nor on creatinine clearance. The urinary excretion of albumin and β2-MG was also unchanged. The excretion of the proximal tubular enzymes alkaline phosphatase and N-acetyl-β-glucosaminidase was increased. No significant difference between iopentol and iohexol was found.

Negligible effect of non-ionic radiocontrast medium exposure on microalbuminuria in patients undergoing coronary angiography

Contrast-induced nephropathy (CIN) remains one of the most common hospital-acquired acute renal deterioration in patients undergoing angiographic procedure. Transient and massive non-selective proteinuria of glomerular origin was previously reported in patients with stable renal function shortly after ionic radiocontrast medium (RCM) exposure. Since non-ionic RCM is mostly used nowadays for coronary angiographic procedures, the effects of non-ionic RCM exposure on microalbuminuria might be worthy to be clarified. By measuring urine albumin-creatinine-ratio, we found that exposure to non-ionic, low osmolar RCM has almost negligible effect on either the presence or the levels of microalbuminuria in patients who underwent coronary angiography using ordinary dose. The findings of neutral effect of non-ionic RCM on microalbuminuria in our study might offer another rationale in an effort to prevent CIN. Further large-scaled clinical trials in delineating the effects on microalbuminuria after non-ionic RCM exposure were warranted, particularly in those with pre-existing renal insufficiency, to clarify the clinical implications of our study results.

Increased serum alkaline phosphatase activity: a possible indicator of renal damage

Increased levels of serum alkaline phosphatase (ALP) (E.C.3.1.3.1.) were observed in 25 patients with various urological conditions involving the kidneys: malignancy, complicated nephrolithiasis, and surgical and percutaneous manipulations. Other possible sources for increased ALP level, mainly hepatic and osseous, were excluded by history, laboratory tests, and liver and bone imaging. Studies of isoenzymes of ALP did not show a distinctive pattern. ALP levels returned to the normal range by treating the underlying lesions involving the kidney: nephrectomy, complete removal of stones, or removal of nephrostomy. The increase in serum ALP activity may be derived from the injury to the brush border membrane of the renal tubular cells. Renal function impairment and contrast media induced nephrotoxicity may also be responsible for the increased serum ALP. Serum ALP may be a marker for involvement of the kidneys in pathological processes and an indicator of complete treatment. This clinical observation is worthy of further study.