Long-term outcome of patients with contrast-induced nephropathy

Introduction

Despite the use of several prophylactic approaches, contrast-induced nephropathy (CIN) remains a clinical problem. CIN is the third leading cause of hospital-acquired renal failure. CIN is associated with several risk factors such as diabetes and hypertension as well as with prolonged hospitalization and increased mortality. Little is known about long-term renal outcome. Within the last 10 years we have performed nine controlled studies on prophylaxis of CIN with a total number of about 1,200 patients. It was the aim of this study to investigate the long-term outcome of patients with CIN within these studies.

Methods

This study presents the data of the first 25 patients with CIN (planned: 80 patients) including serum creatinine 1 week, 1 month, 6 months and 1 year after the contrast medium. The outcome was investigated by chart review and telephone call.

Results

All patients were Caucasian and had a mean age of 69.6 ± 10.6 years. Eight were female, 17 were male. Twenty-four patients had risk factors for CIN such as diabetes (8%), hypertension (44%) or both (28%) and preexisting renal impairment (15%) prior to contrast medium application. Their mean serum creatinine before contrast medium application was 1.81 ± 1.21 mg/dl. The contrast procedure was coronary angiography in 18 patients and CT in seven patients. For prophylaxis of CIN, six patients received N-acetylcysteine and three patients received both N-acetylcysteine and theophylline prior to contrast medium exposition. Mean serum creatinine 48 hours after contrast medium was 2.36 ± 1.36 mg/dl (P < 0.01 vs 0 hours). The mean maximum creatinine increase was 0.64 ± 0.26 mg/dl (P < 0.01 vs 0 hours). Four patients (16%) died during the first week after contrast medium, one of them despite initiation of dialysis 2 days after contrast application.

One year after CIN, the mean serum creatinine in the survivors was 1.85 ± 1.39 mg/dl (P = 0.48 vs 0 hours). A clinical relevant increase of >0.3 mg/dl compared with baseline creatinine was found in six (24%) patients.

Conclusion

CIN is a serious complication of contrast medium administration and is associated with an increased mortality and long-time morbidity.