Radiocontrast nephropathy: is it dose related or not?

OBJECTIVE To assess the safety of high dose non-ionic contrast media during a single radiological procedure in patients with pre-existing renal impairment. METHODS One hundred eighteen patients, with serum Creatinine greater than 1.3 mg/dl who were undergoing coronary angiography or percutaneous transluminal coronary angiography (PTCA) were included in the study. All patients received the nonionic dye ULTRAVIST (lopromide). Serum creatinine were measured before, 48 hours and 1 week after the administration of contrast agent. An acute contrast induced reduction in renal function was defined as an increase in Serum Creatinine concentration of >=0.5 mg/dl, 48 hours after the administration of contrast agent. All patients with end stage renal disease or patients undergoing coronary bypass surgery within a week after coronary angiography or had any concomitant factors that could cause acute renal failure e.g., sepsis, hypotention, etc., were excluded. Patients receiving a dose of upto 100 ml of contrast agent (low dose group) were separated from those who received greater than 100 ml of contrast agent (high dose group). Patients in both groups had similar characteristics in terms of sex, age, weight and underlying disease. Student's t-test was used for statistical analysis. RESULTS The mean age of our patients was 62.3+/-8.83 (range 40-84 years). There were 93 (78.8%) males and 25 (21.2%) females. The mean pre-contrast creatinine in the low contrast group was 1.97+/-0.92 and high dose group was 2.16+/-1.90 (p=0.48). The post-contrast Creatinine at 48 hours was 2.11+/-1.11 and 2.06+/-1.39 in the groups receiving low and high dose contrast agents respectively (p=0.830), while at 7 days post-contrast it was 2.17+/-1.28 and 1.95+/-1.43 respectively in the two groups (p=0.391). The contrast-induced reduction in renal function (rise in serum Cr >=0.5 mg/dl above base line) occurred in 14% (n=8) of patients in low dose and in 11% (n=7) in high dose contrast group (p=0.830, insignificant). CONCLUSION The results of our study confirm that high dose non-ionic contrast is not associated with increased risk of contrast-mediated nephrotoxicity in patients with pre-existing renal insufficiency undergoing cardiac angiography (p=0.830, insignificant).