Renal vasoconstriction after low and high osmolar contrast agents in ischemic and non ischemic canine kidney.

We have assessed the effect of contrast media on renal blood flow before and after inducing renal ischemia. Diatrizoate, iopamidol and ioxaglate were injected within 15 seconds at 20 min intervals, at the dose of 1 ml/kg during a control period and 15 min after applying an aortic clamp to reduce the renal perfusion pressure to 70 mmHg. During the control period iopamidol, ioxaglate (17 +/- 13%) and diatrizoate (16 +/- 2%) induced a comparable decrease in renal blood flow (RBF). During the ischemic period the effects of diatrizoate on renal hemodynamic were dramatically enhanced. Ioxaglate andiopamidol induced a 20 +/- 12 and a 32 +/- 9% decrease in RBF at 1 minute, respectively. Iopamidol induced an increase in renal vascular resistance (RVR) from 0.8 +/- 0.08 to 1.46 +/- 0.26 mmHg min/ml (p less than 0.05). Ioxaglate induced an increase in RVR from 0.8 +/- 0.09 to 1.36 +/- 0.38 (p less than 0.05). Diatrizoate induced a 77 +/- 10% decrease in RBF and a maximum increase in RVR at 1 minute from 0.9 +/- 0.09 to 26 +/- 12 mmHg min/ml. There was still a 36 +/- 14% and a 23 +/- 13% decrease in RBF 10 and 20 min after diatrizoate administration. These changes were significantly higher than those observed with all contrast media during the control period and low osmolar contrast media during the ischemic period. We have thus shown that ischemia potentiates the renal vascular effect of contrast media.(ABSTRACT TRUNCATED AT 250 WORDS)