contrast studies

2. • Contrast-induced nephropathy (CIN) is a generally reversible
form of acute kidney injury (AKI) that occurs soon after the
administration of radiocontrast media.
• After intravascular CM injection, immediate renal toxicity
may occur, and in most cases it remains fortunately free of
significant clinical consequences.

3. of CINincludes:
anabsolute increasein
serum creatinine of >0.3
mg/dL or a>50% relative
increase in serum
creatinine from the baseline
value or urine output
reduced to less than
0.5 mL/kg/hr for at least 6
hours
within 48
hours after
exposure to
contrast
agent,
in the
absence of
alternative
causesfor
acute kidney
injury

4. 1 2 3 4 Weeks
Serum
Creatinine
In most cases,the
decline in renal
function is mildand  (in patients
withCIN
riskfactors)
S.Cr.usually returns
to the baselinevalue
after 1–3weeks
transient
Somepatients have
apersistentdecline
in renal functionand
requireRRT

5. Incidence
of CIN
Risk
Factors
Contrast
Dose
Typeof
Radiologic
procedure
Contrast
Type

6. • The incidence of contrast agent–related nephropathy is
estimated to be 2% to 5%, and up to 25% of those with CIN will
have persistent renal dysfunction.
• Clinical manifestations are highly variable and may be absent or
proceed to oliguria.
• CIN in patients with normal kidney function is rare.
• CIN is the third most common cause of acute kidney failure in
hospitalized patients.

8. • ThePathogenesis of CINis stillunknown
butmaybeconsidered multifactorial.

10. • A decreased incidence of contrast nephropathy appears to be
associated with nonionic agents, which, are either low osmolal
(500 to 850 mosmol/kg)or iso-osmolal (approximately290 mosmol/kg).

11.  Iodixanol, the only currently available iso-osmolal nonionic contrast agent
(approximately 290 mosmol/kg), may be associated with alower risk of nephropathy
than some low-osmolal agents, particularly iohexol

12. • Most of the studies indicate that the higher volume of CM is
especially deleterious in the presence of other risk factors , with
lower doses of contrast being safer, but not free of risk.
• Evenrelatively low doses of contrast (less than 100 ml) can induce
permanent renal failure and the need for dialysis in patients with
chronic kidney disease.

13. • In this study, low dose wasdefined by aformulaas:
• However, diabetic patients with aserum creatinine concentration
>5mg/dL (440 micromol/L) may be at risk from aslittleas20 to
30 mLof contrast.

14. • There is no specific treatment once CI-AKI develops, and
management must be asfor any causeof ATN,with the focus on
maintaining fluid and electrolyte balance.
• The best treatment of contrast-induced kidney injury is
prevention.

15. Imaging studies not requiring• Consider alternate
contrast medium.
• The use of lower doses of low- or iso-osmolal nonionic contrast
agents and avoidance of repetitive studies that are closely spaced
(within 48 to 72hours).
• Avoidance of volumedepletion.
• Concomitant nephrotoxic drugs such asNSAIDand nephrotoxic
antibiotics, ACEIand diuretics should be discontinued 48 hours
prior to contrastadministration.

16. • Isotonic saline is superior to one-half isotonic saline since isotonic
saline is amore effective volume expander.
• In a study by Mueller et al, intravenous administration of isotonic
saline was found to be superior, compared with half-isotonic
saline, in reducing the rates of CIN after percutaneous coronary
intervention (0.7% versus2%,respectively).
Mueller C,Buerkle G,Buettner HJ,et al. Prevention of contrast media-associated nephropathy:
randomized comparison of 2 hydration regimens in 1620 patients undergoing coronary
angioplasty. Arch Intern Med. 2002;162(3):329–336.

17. • Sincealkalinization may protect against free radical injury, the
possibility that sodium bicarbonate may be superior to isotonic
saline hasbeen examined in anumber of randomized trialsand
meta-analyses.
• Theresults were conflicting assome showed asignificantly lower
rate of contrast-induced nephropathy with sodium bicarbonate,
while others found equivalentrates.

18. HydrationwithSaline
IVF=1 mL/kg/hr (MAX 100 ml/hr) 12 hours pre & 12 hours post
contrast
CHFor left ventricular ejection fraction(LVEF)<40%?
0.5 ml/kg/hr (max 50 ml/hr) 12 hrs pre & post contrast

19. • Given that an increasing number of individuals receive contrast as
outpatients, this trial has evaluated the effectiveness of oral hydration
in preventing contrast nephropathy.
• 53 patients were randomly assigned to either unrestricted oral fluids or
to normal saline at 1 mL/kg per hour for 24 hours beginning 12 hours
prior to the scheduled catheterization . AKI was significantly more
common with oral hydration (35 versus4%).

20. BicarbonateDosing
IVF=150 meq of sodium bicarbonate in 850 ml of D5W
3 ml/kg bolus (MAX 300 ml) 1 hour prior to procedure and 1
mL/kg/hour (MAX 100 ml/hr) during and for 6 hours post-
procedure.

21. RenalGuardsystem

22. Renal Guardsystem
• The RenalGuard™ System is a real-time measurement and matched
fluid replacement device designed to accommodate the RenalGuard
therapy, which is based on the theory that creating and maintaining a
high urine output is beneficial by allowing a quick elimination of
contrast media, and, therefore, reducing its toxic effects.
Patients with
eGFR≤30mL/min
or a riskscore≥11
Controlgroup
NaHco3+NAC
RenalGuardgroup
Isotonic saline +NAC+
furosemide

23. • Contrast-induced acute kidney injury occurred in 16 of 146 patientsin
the RenalGuard group (11%) and in 30 of 146 patients in the control
group (20.5%).
• Conclusion:
RenalGuard therapy, including hydration with normal saline plus high
dosesof NACin combination with alimited (0.25 mg/kg) doseof
furosemide, seemsto be an effective renoprotective strategy for
patients at high risk for CI-AKI.

24. Nephroprotectivedrugs
• There are great heterogeneity and conflicting
available clinical trials and meta-analysis examining
results in the
the
acetylcysteine prevention of contrasteffectiveness of
nephropathy .
• Being a precursor for glutathione synthesis, NAChas the potential
to diminish oxidative stress by directly scavenging superoxide
radicals and increasing intracellular glutathione.
Drager LF,Andrade L,BarrosdeToledoJF,Laurindo FR,Machado CesarLA,SeguroAC.Renaleffects of N
acetylcysteine in patients at risk for contrast nephropathy: decreasein oxidant stress-mediated renaltubular
injury. Nephrol Dial Transplant. 2004;19(7):1803–7.

25. Nephroprotectivedrugs

26. Nephroprotectivedrugs
• Patients were randomly assigned either to receive the antioxidant
acetylcysteine (600 mg orally twice daily) and 0.45 percent saline
intravenously, before and after administration of the contrast
agent, or to receive placebo andsaline.
• Conclusion:
Prophylactic oral administration of acetylcysteine, along with
hydration, prevents the reduction in renal function induced by
the contrast.

27. Nephroprotectivedrugs
• 2308 patients undergoing angiography received either
acetylcysteine (1200 mg orally twice daily) or placebo on the day
before and after angiogram.
• Patients had at least one of the following risk factors: age>70
years, CKD,diabetes mellitus, heart failure or LVejection fraction
<45 percent, or shock.
• There was no difference in the development of CI-AKI (12.7
percent in both groups).

28. Nephroprotectivedrugs
 Since the agent is potentially beneficial, well tolerated, and relatively inexpensive, 2012
KDIGO guidelines thatsuggest administration of acetylcysteine to patientsat high risk.
AcetylcysteineDosing
Tolerating POintake?
600-1200 mg capsulesPOQ12h X4doses
2 dosespre-contrastand 2 dosespost-contrastis optimal
EmergentProcedure?
1 dosebefore and 3 dosespost cath or procedureis acceptable(Q12h x4 doses
total)
IVAcetylcysteine?
600-1200 mg IV x 1 over 15 minutes, then 600-1200 mg PO/PTq12h x4 doses
post-procedure: For a high risk patient undergoing cardiac catheterization or
PEprotocolCTscanwithno PO access

29. Nephroprotectivedrugs
• Statins may improve endothelial function, reduce arterial
stiffness, and reduce inflammation and oxidative stress.
• There are no sufficient data to support the use of statins solely for
the prevention of contrastnephropathy.
SugiyamaM, Ohashi M, Takase H,et al. Effects of atorvastatin on inflammation and oxidative stress.
Heart Vessels2005; 20:133.

30. Vasoactivedrugs
• Low-dose dopamine failed to show a protective effect on renal function
in patients undergoing contrast media exposure, and was even
associated with a deleterious effect on the severity of renal failure and
its duration.
GareM, Haviv YS,Ben-YehudaA, et al. Therenal effect of low-dose dopamine in high-risk patients
undergoing coronary angiography. JAm Coll Cardiol.1999;34(6):1682–1688.

31. Vasoactivedrugs
• Fenoldopam is aspecific dopamine-1 receptor agonist that augments
renal plasma flow while decreasingsystemic vascularresistance.
• Aprospective randomized trial (CONTRAST)assessed the effectiveness
of fenoldopam in 315 patients undergoing a cardiovascular procedure
who had CKDwith an estimated creatinine clearance <60mL/min.
• Unfortunately it also fails to reduce CINincidence in CKDpatients.

32. Vasoactivedrugs
• The clinical benefit of the competitive adenosine antagonist
theophylline isdebated.
• In a randomized study by Huber et al, prophylactic intravenous
administration of theophylline 200 mg reduced the incidence of CIN in
100 patients at risk, ascompared with placebo (4%versus 16%).
• However, in other randomized studies, administration of theophylline
did not provide any benefit in reduction of CIN rates compared with
placebo.
• Huber W,Ilgmann K,PageM, et al. Effect of theophylline on contrast material-nephropathy in patients with
chronic renal insufficiency: controlled, randomized, double-blinded study. Radiology. 2002;223(3):772–779.
• Shammas NW, Kapalis MJ, Harris M, McKinney D, Coyne EP.Aminophylline does not protect against radiocontrast
nephropathy in patients undergoing percutaneous angiographic procedures. JInvasive Cardiol. 2001;13(11):738–
740.

33. Vasoactivedrugs
• A20 ng/kg/min PGE1infusion hasasignificant protective effect on
post-PCISCrelevation,
• But higher infusion rates are not associated with increased benefits,
probably due to the associated decrease in systemic blood pressure.
.

34. Vasoactivedrugs
• In a small, randomized, placebo controlled study of 35 patients, eGFR
was preserved in patients treated with nitrendipine but decreased in
patients that received placebo.
• Bycontrast, in three other studies, the change in serum creatinine level
did not differ significantly withcalcium antagonists.
.

35. Hemodialysis
• Iodinated contrast agents are readily dialyzable.
• The plasma clearance of most modern contrast media is 50–70 mL/
min, with more than 80% removed from the plasma within 4–5 hours of
hemodialysis.
• However, Reduction of CIN with dialysis is also not biologically plausible
since the CMwould reach the kidneys within one or two cardiaccycle.
• Subsequent removal of CM is unlikely to stop the cascade of renal
injury, which would have alreadybegun.
Dawson P.Contrast agents in patients on dialysis. Semin Dial. 2002;15(4):232–236.

36. Hemofiltration
• In patients with chronic renal failure who are undergoing
percutaneous coronary interventions,
• periprocedural hemofiltration given in an ICU setting appears to
be effective in preventing the deterioration of renal function due
to CIN
• and is associated with improved in-hospital and long-term
outcomes.

37. • Routine hemofiltration or hemodialysis for the prevention of
contrast nephropathy in patients with CKDis not recommended.