The effect of intracarotid nonionic contrast media on the blood-brain barrier in acute hypertension.

PURPOSE To determine whether acute hypertension (HT) is a risk factor for damage to the blood-brain barrier in carotid angiography with nonionic contrast media. METHODS Anesthetized rats received intravenous injections of technetium-99m-pertechnetate and horseradish peroxidase. Two groups of rats received metaraminol to raise their blood pressure to between 165 and 190 mmHg peak systolic and then received intracarotid injections of saline or iopamidol. Two other groups remained normotensive and received intracarotid injections of saline or iopamidol. Animals were perfused with a fixative solution and their brains removed. Activity of extravasated Tc-99m-pertechnetate was determined to assess blood-brain barrier breakdown. Brains were then sectioned, treated histochemically to visualize extravasated horseradish peroxidase, and ranked visually according to horseradish peroxidase staining. RESULTS Extravasation of both tracers was significantly greater in the hypertensive group that received contrast media than in the other three groups. CONCLUSIONS Acute hypertension potentiates the blood-brain barrier-damaging effects of nonionic contrast media during carotid angiography in rats.