Blood pressure medications that block the renin-angiotensin-aldosterone system (RAAS) may increase the likelihood of contrast-induced acute kidney injury (AKI) among patients undergoing coronary angiography, a study found.

Korean investigators retrospectively studied 2,644 patients who under coronary angiography. The group included 1,322 users of RAAS blocking drugs (ACE inhibitors or angiotensin receptor blockers (ARBs) and 1,322 propensity-matched nonusers of these medications. Contrast-induced AKI occurred in 11.4% of users of the RAAS blocking drugs compared with 6.3% of nonusers, a statistically significant difference between study arms, researchers reported in the American Journal of Kidney Diseases (2012; published online ahead of print). After adjusting for multiple variables, RAAS blockade was independently associated with a significant 43% increased odds of contrast-induced AKI.

The investigators, led by Ji Yong Jung, MD, PhD, of Gachon University Gil Hospital in Incheon, defined AKI according to AKI Network (AKIN) criteria: an 0.3 mg/dL or greater absolute increase in serum creatinine levels or a relative 50% or greater serum creatinine rise from baseline within 48 hours after exposure to the contrast medium.

Continue Reading

The researchers noted that the specific pathways responsible for the pathogenesis of contrast-induced AKI have yet to be elucidated, but some mechanisms have been proposed, such as direct tubular toxicity of the contrast media and endothelin- and adenosine-induced vasoconstriction.

Because of the greater use of RAAS in patients with chronic kidney disease or cardiovascular disease, “the potential for worsening nephrotoxicity is of increasing concern,” the authors wrote.