Beschreibung
The association of the administration of iodinated contrast agents during imaging procedures and the development of contrast-induced acute kidney injury (CI-AKI) has been described in human and veterinary medicine. The exact mechanism of injury is not fully understood to date and continues to be investigated. Often, CI-AKI affects patients with underlying diseases, first and foremost with an already known chronic kidney disease. In contrast, transient CI-AKI is more frequently observed in patients with healthy kidneys.
In dogs, a relative frequency of patients with portosystemic shunt (PSS) was noticed in one study, but without a calculation of incidence. Therefore, the aim of this retrospective study was to evaluate the incidence and perioperative risk factors of CI¬AKI in dogs after therapy for congenital PSS. For this purpose, clinical and hemodynamic parameters, as well as plasma creatinine, were evaluated in dogs that received catheter-based or surgical closure of a PSS. The hypothesis was that high levels of contrast and intraoperative hypotension increase the risk of developing CI¬AKI.
In total, the patient data of 290 dogs that received an iodine-containing contrast medium intravenously in the context of an occlusion of a congenital PSS were evaluated. Dogs with an initial creatinine elevation were excluded.
The course of plasma creatinine from day 0 to day 2 and day 7 was analyzed. According to current guidelines, an increase in creatinine of = 26.5 µmol/l was defined as CI-AKI. The following potential risk factors were evaluated: Age, initial creatinine, contrast amount, intraoperative hypotension, duration of anesthesia, body temperature at the end of the procedure, postoperative ascites, and blood transfusion. Creatinine¬values of the 3-month follow-up were also analyzed.
The median age of the dogs was 11.9 months (4.2 to 109.5 months) and median weight was 9.1 kg (1.4 to 50.0 kg). 136 dogs had an intrahepatic and 154 an extrahepatic shunt. The initial median creatinine was 39,0 µmol/L (Range 19,0 – 79,0 µmol/L).
The incidence of CI-AKI was 0% at day 2 and 0.7% (2/290 dogs) at day 7.
High initial creatinine levels showed a significant influence in terms of a greater creatinine drop on day 7. None of the other risk factors analyzed showed a significant correlation with the development of plasma creatinine on day 7. However, it was striking that both patients with CI-AKI were in the severe hypotension group (mean blood pressure = 40 mmHg).
At the 3-month follow-up, there was an overall significant increase in creatinine levels (P < 0.0001), with animals with complete occlusion having significantly (P < 0.0001) higher levels. Of the two dogs with postoperative CI-AKI, one had a creatinine value in the middle of its group, but the second had the highest value.
The low incidence of CI-AKI in this study is consistent with human medical studies excluding patients with pre-existing elevated renal values. It is probably influenced by the described high glomerular filtration rate in dogs with PSS and by the strict infusion management.
In the future, the low incidence needs to be verified in a broader study population, using new more sensitive markers of renal injury. In particular, the possible influence of severe hypotension needs to be analyzed in this regard.
