Radiocontrast Radiocontrast NephropathyNephropathy

Jason S. Finkelstein, M.D.Jason S. Finkelstein, M.D.Tulane University HSCTulane University HSCDivision of CardiologyDivision of Cardiology

3/2/043/2/04

OutlineOutline

• Incidence and Clinical Features of RCNIncidence and Clinical Features of RCN

• Risk FactorsRisk Factors

• PathophysiologyPathophysiology

• Agents used for Prevention of RCNAgents used for Prevention of RCN

IncidenceIncidence

• In the year 2000, an estimated 1.8 million In the year 2000, an estimated 1.8 million caths were performed in the UScaths were performed in the US

• Two studies looked at 1826/1196 patients and Two studies looked at 1826/1196 patients and the incidence of RCN was 14.4% & 11.1% the incidence of RCN was 14.4% & 11.1% respectivelyrespectively

• 0.3-4% of patients required short-term dialysis0.3-4% of patients required short-term dialysis• Approx 60,000 cases of RCN occur each yearApprox 60,000 cases of RCN occur each year

DefinitionDefinition

• Absolute increase of Cr > 0.5 mg/dl Absolute increase of Cr > 0.5 mg/dl or relative increase of 25-50% from or relative increase of 25-50% from baseline within 48 hours of contrast baseline within 48 hours of contrast exposure in absence of other causesexposure in absence of other causes

• Third most common cause of acute Third most common cause of acute renal failurerenal failure

DefinitionDefinition

• Typically occurs within 24-48 hours Typically occurs within 24-48 hours of contrast exposureof contrast exposure

• Creatinine typically peaks in 3-5 days Creatinine typically peaks in 3-5 days and returns to baseline in 1-3 weeksand returns to baseline in 1-3 weeks

• RCN is non-oliguric in most patientsRCN is non-oliguric in most patients

OutcomeOutcome

• Causes increased length of hospital Causes increased length of hospital stay and costsstay and costs

• Significant in-hospital morbiditySignificant in-hospital morbidity

• 5-10% require transient dialysis; 5-10% require transient dialysis; <1% require long term dialysis<1% require long term dialysis

Increased mortalityIncreased mortality

• 3.8% -- Increase in Cr 0.5-0.9 mg/dl3.8% -- Increase in Cr 0.5-0.9 mg/dl

• 64% -- Increase in Cr > 3.0 mg/dl64% -- Increase in Cr > 3.0 mg/dl

OsmolalityOsmolality

• Contrast media are water soluble structures Contrast media are water soluble structures composed of triiodobenzene ring with composed of triiodobenzene ring with varying numbers of iodine moleculesvarying numbers of iodine molecules

• Increased iodine content results in increased Increased iodine content results in increased osmolalityosmolality

• Pooled data from 25 randomized trials have Pooled data from 25 randomized trials have shown that high osmolality agents pose a shown that high osmolality agents pose a greater risk of CN than low-osmolality agentsgreater risk of CN than low-osmolality agents

Risk Factors for RCN Risk Factors for RCN

• Pre-existing renal insufficiency (37%)Pre-existing renal insufficiency (37%)

• Diabetes (risk is 4.1%)Diabetes (risk is 4.1%)

• Contrast volumeContrast volume

• DehydrationDehydration

• Advanced AgeAdvanced Age

• Nephrotoxic drugs (ACE, NSAIDS)Nephrotoxic drugs (ACE, NSAIDS)

• CHF, Liver diseaseCHF, Liver disease

PathophysiologyPathophysiology

• Medullary ischemiaMedullary ischemia

• Direct tubular toxicityDirect tubular toxicity

• Tubular obstructionTubular obstruction

Medullary IschemiaMedullary Ischemia

• Contrast agents cause a selective renal Contrast agents cause a selective renal medullary vasoconstriction medullary vasoconstriction

• Shunting of blood to the renal cortexShunting of blood to the renal cortex

• Also known as the “steal phenomenon”Also known as the “steal phenomenon”

• This leads to tubular injuryThis leads to tubular injury

Tubular obstructionTubular obstruction

• Possible role in pathogenesis of RCNPossible role in pathogenesis of RCN

• Precipitation of Dye crystals in the Precipitation of Dye crystals in the renal tubulesrenal tubules

• In presence of dehydration, In presence of dehydration, precipitation of urate or dye crystals precipitation of urate or dye crystals could lead to tubular obstructioncould lead to tubular obstruction

Direct Tubular ToxicityDirect Tubular Toxicity

• Toxic ATNToxic ATN

• Oxygen Free RadicalsOxygen Free Radicals– Leads to apoptosis in renal tubular and Leads to apoptosis in renal tubular and

glomerular cellsglomerular cells

Iohexol Cooperative StudyIohexol Cooperative Study

• ObjectiveObjective– To compare the incidence of contrast To compare the incidence of contrast

nephrotoxicity between nonionic nephrotoxicity between nonionic “Iohexol” and the ionic contrast agent “Iohexol” and the ionic contrast agent “diatrizoate” in a large population of low “diatrizoate” in a large population of low and high risk patients undergoing and high risk patients undergoing angiogramangiogram

– 1196 pts, randomized trial1196 pts, randomized trial

ConclusionConclusion

• The incidence of RCN depends on the The incidence of RCN depends on the presence of risk factorspresence of risk factors

• Pts with CRI and DM are at highest Pts with CRI and DM are at highest riskrisk

• RCN can be associated with RCN can be associated with significant morbidity and mortalitysignificant morbidity and mortality

• There are preventive interventions to There are preventive interventions to decrease the risk of toxicitydecrease the risk of toxicity