Volume 195 - Issue 5
Contrast induced nephropathy in patients with pre-existing renal impairment undergoing invasive coronary procedures — a long-term follow-up
Authors: Akash Dhawan, Devang Parikh, Ibrahim Shugman, John French, Hisham Hallani, Clyne Fernandes and Craig P Juergens
Med J Aust 2011; 195 (5): 268-269. || doi: 10.5694/mja11.10368
Published online: 5 September 2011
Published online: 5 September 2011
To the Editor: Contrast induced nephropathy (CIN) is one of the most important and frequent complications of invasive coronary procedures.1 We have previously reported a multicentre randomised trial comparing use of iso-osmolar and low osmolar contrast agents (iopromide and iodixanol, respectively) in patients with pre-existing renal impairment.2 The overall proportion of patients developing CIN by Day 7 was around 25%, and there was no statistical difference between the different contrast media.
There have been few prospective randomised controlled trials to determine the late effects on renal function and outcomes in relation to dialysis and mortality in patients who developed CIN after invasive coronary procedures. We report here on the long-term follow-up of patients enrolled in our initial study.
Of the original cohort of 191 patients, 21 were excluded because of lack of follow-up information. We divided patients into two groups based on whether or not they had initially developed CIN, defined as an absolute increase in the serum creatinine concentration of at least 44 μmol/L or by a relative increase of at least 25% from the baseline value on Day 2 or 7 after exposure to the contrast media.
The primary end point was persistent renal impairment, which we defined by these same criteria for serum creatinine, and alternatively, by an absolute reduction in estimated glomerular filtration rate (eGFR) of at least 10 mL/min/1.73 m2 (accounting for the coefficient of variation of creatinine and also the age-related decline in GFR3-5). The secondary end point was a composite of death and need for dialysis. Median length of follow-up was 43 months (interquartile range, 31–48 months).
Latest serum creatinine results were available from physicians, hospital records or private laboratories for 157 patients. Significantly higher proportions of patients who had CIN at baseline showed evidence of persistent renal impairment compared with patients who did not have CIN at baseline, based on both serum creatinine results (20/40 v 31/117; P = 0.006) and eGFR (22/40 v 28/117; P < 0.001).
Mortality was determined for all 170 patients by direct contact or from the national death registry. A significantly higher proportion of patients who had CIN at baseline (2/41) compared with those who did not have CIN (3/129) needed dialysis (P = 0.60). Twelve patients who had CIN at baseline had outcomes of death, dialysis or both, compared with 32 in the other group (P = 0.57).
Multivariate analysis showed CIN at Day 2 or 7 was an independent predictor of persistent renal impairment (odds ratio, 3.31 [95% CI, 1.39–7.86]; P = 0.007). Age, diabetes mellitus, sex, hypertension, body mass index, contrast type and baseline eGFR were not predictive.
This long-term follow-up showed that CIN after invasive coronary procedures is associated with increased risk of persistent renal dysfunction in patients with pre-existing renal dysfunction. Physicians should be alert to this complication.
Competing interests
No relevant disclosures.
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