BACKGROUND: CT scan is nowadays the quickest imaging technique, being low cost, available and with relatively few contraindications, as opposed to MRI. The radiation dose used has been significantly lowered with the technological advances of today. NCCT gives us much less information in most clinical situations requiring CT. Contrast induced nephropathy (CIN) is a controversial complication of iodinated contrast media. It has been extensively studied in different patient populations and risk factors have been defined. As longevity emerges, the question of cost-effectiveness of contrast media diagnostics in the elderly is raised. There is sparse literature regarding CIN among the oldest-old (>85 years old). SZMC is one of two hospitals in Israel (population 9 million) having patients of this age group. We set to study the effect of CM on renal function in this population.
METHODS: We collected data on consecutive patients above 85 years of age undergoing CT using IVCM (obviously none with serum creatinine above 1.5). Serum creatinine was recorded before the exam and 12-48 hours after the IVCM was administered. GFR before and after the CT was estimated using the MDRD equation. The percentage of eGFR difference between the two measurements was calculated. Renal damage was defined as a reduction of more than 25% in eGFR.
RESULTS: 56 patients were studied in this time period. Median age was 89.5 (IQR 87-97); 60% of the patients were females; median MDRD before the IVCM was 72(55-91); median MDRD after was 77 (55-94); median MDRD gap was -2.5 (-9.5 to +8.1), not significantly different from zero. The percentage of renal function deterioration was 8.9% (5/56) while in the general patient population it is at least 10%. The only variable found close to significance (by univariate analysis for risk factors of renal function deterioration) was male gender (p=0.07). Logistic regression analysis did not reveal any significant risk factor.
CONCLUSIONS: Among our study group of the oldest-old we found no significant renal damage caused by IVCM. As the study size is small, much larger studies are required to reach definite conclusions on that unique group of patients.
