CONTRAST INDUCED NEPHROPATHY(CI-AKI)

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CIN ,third most common cause of AKI.
asymptomatic.
prevention is the one to be emphasised in case of CI-AKI.

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CONTRAST INDUCED NEPHROPATHY(CI-AKI)

  1. 1. CIN in PCI and Management Dr. Nagula Praveen PG I yr (DM)
  2. 2. CONTRAST INDUCED NEPHROPATHY * (* CI-AKI)
  3. 3.  Introduction  Epidemiology  Criteria/Definition  Patho physiology  Risk markers  Risk score  Contrast agents  Clinical features  Management  Future...  Consensus statements  Conclusions  Take home message.
  4. 4. INTRODUCTION  CIN (CI -AKI ) third leading cause of acute kidney injury in hospitalized patients.  Most frequent renal complication of endovascular interventional procedures.  Unrecognized as it is asymptomatic..  Increases short and long term morbidity and mortality.  Treatment is limited to supportive measures while awaiting the resolution of renal impairement.  Prevention is the one to be emphasised in case of CI –AKI.
  5. 5. QUESTIONS IN MIND  How CIN occurs ?  What is the definition of CIN, why change in creatinine only?  Are contrast agents directly nephrotoxic ?  How can it be prevented ?  What is the best prescription for hydration ? IV/oral  Is sodium bicarbonate better than sodium chloride as an intravenous hydration solution?  Is the latest iso-osmolar agent better than the low osmolar agents currently in use ?  Why pathophysiology could not be put into practice of management ?  Why there are conflicting results?  Will CIN be never having an effective treatment ?
  6. 6. History  In 1906,Von Lichtenberg and Voelcker used 2% colloidal silver solution,for retrograde pyelography studies.(toxic to kidneys,death).  In 1920, Osborne and colleagues,10% “NaI” for Rx of syphilis, fortuiously found it to be radiopaque ,excreted by kidneys.--first pyelogram.  Selectan - Moses Swick  Uroselectan ,1927 – increased solubility and less toxicity.  In 1993, Hippuran was introduced.  Binz and Rath – Neo ipax(Iodoxyl) and diodrast (Diodone)  1927 – Werner Frossmann – self catheterization,using urinary catheter( antecubital vein),(NaI)  1923,Berbrich and hirsch –femoral angiogram  1924,Brooks – first angiogram (under GA).
  7. 7. Epidemiology  Incidence in General population <2%.*  Overall incidence is 14.5% (epidemiological study)^  Among diabetics, mild –moderate CKD – 9-40%.#  Severe CKD 50-90%.  5% of hospital admissions.**  Cases of CI-AKI leading to dialysis are rare (0.5 to 2.0%).  When it leads to dialysis in hospital mortality of 35.7%,18.8% - 2 yr survival rate $ . *Berg et al, Nephroptoxicity related to contrast media.Scand J urol Nephrol 2000;34:317-322. ^Lang et al; incidence of contrast medium induced acute tubular necrosis,radiology 1981:138:203-206. #Manske et al;contrast nephropathy in azotemic diabetic patients undergoing coronary angiography. Am J Med 1990;89:615-620. **Hou et al ;hospital acquired renal insufficiency Am J Med 1983;74:243-248. Mc collough et al,Am J Med 1997.
  8. 8. Criteria  Pakfetrat et al were the first to investigate risk factors for CIN on the basis of RIFLE criteria.  They found it impossible to reach conclusive results in the injury and failure categories. Pakfterat el,Risk factors for contrast related acute kidney injury according to RIFLE criteria, Iran J Kidney Dis ,2010:4(2):116-122
  9. 9. Comparison of RIFLE criteria and CIN criteria
  10. 10. Diagnostic criteria for CIN
  11. 11. KDIGO Definition  CI-AKI is defined by the Kidney Disease Global Outcomes (KDIGO) guidelines as an “…increase in serum creatinine of 0.3 mg/dL or greater within 48 hours of contrast use or a 50% or greater increase from baseline serum creatinine within 7 days”. From Kidney disease: Improving Global Outcomes (KDIGO) Acute Kidney Injury Work Group. KDIGO CLINICAL PRACTICAL GUIDELINES FOR ACUTE KIDNEY INJURY. Kidney Int 2012;Suppl 2:1 -138;
  12. 12. course  The serum creatinine usually increases within 24 -48hrs after contrast administration, peaks at 3 to 5 days,and returns to baseline in 1 -3 weeks.
  13. 13. Is relative increase in serum creatinine more important than absolute increase in serum creatinine, does it matter much????? certainly….. Kidney international;2006:69:S4
  14. 14. Relation of serum creatinine and GFR Finn et al ;Nephrol Dial Transplant (2006)21;i2-i10
  15. 15. Mc Cullough et al ;AmJ Cardiol 2006;98:5K-1
  16. 16. CI –AKI CHOLESTEROL EMBOLIZATION INCIDENCE 2% (14.5%) 0.15% (usually underestimated) At risk CKD,DM2 Abdominal aortic aneurysm, diffuse atherosclerosis Prediction Risk score Episodic HTN, eosinophilia SIGNS Usually asymptomatic Signs of peripheral embolization (livedo reticularis,abdominal foot pain,purple toes Decreased urine output course Develops within in 24-48 hrs Develops slowly over weeks to months. Returns to baseline in 1-3 weeks Progress to frank renal failure (50%) Renal replacement therapy - dialysis Usually not needed (2%) Half of the patient progress to frank renal failure requiring dialysis
  17. 17. RENAL PHYSIOLOGY  Each kidney has about 1 million nephrons.  Renal vascular bed – vasa recta, has a high vascular resistance.  Afferent and efferent arterioles control blood flow through renal capillaries.  Glomerular filtration – balance of three forces.  Plasma colloid oncotic pressure - 15 mm Hg.  Bowmann’s hydrostatic pressure – 30 mm Hg  Glomerular capillary pressure – 55 mm Hg (most dominant force).  Net filtration pressure = GCP – (PCP + BHP) ; 55 -45 = 10 mmHg; allows fluid to be forced away from blood through permeable membrane – glomerular filtration.
  18. 18.  ..JCUrine Formation _detailed video_.mp4  Tubuloglomerular feedback:
  19. 19. Pathophysiology  Combination of toxic and ischemic injury to renal tubular cells.  Rheological alterations  Activation of tubuloglomerular feedback  Vasoconstriction  Decreased blood flow  Regional Hypoxia  Cytotoxic effect on renal epithelial cells  Generation of ROS  Increased adenosine or endothelin production
  20. 20.  Vasa recta - same diameter as usual capillaries,increased vascular resistance (several fold longer ).  Viscosity of blood flow through vasa recta is maintained very low.  Low hematocrit – high flow velocities by erythrocytes.  Plasma skimming – right angled arteries.  R =   8  l /  r4
  21. 21.  “Osmotic diuresis theory” – hyperosmotic contrast media – diuresis – TGF – decreased RBF – decreased GFR.  Osmolality has no effect on tubuloglomerular feedback – mannitol,frusemide.  Regional hypoxia – deeper portion of outer medulla –thick ascending loop of henle – exhibit hypoxic damage -high o2requirement due to salt absorption. Adding contrast media –aggravates hypoxic injury.  Isoosmolar agent (IODIXANOL) causes low BP – decreased blood flow to all regions in kidney .  Remnant nephron theory – e GFR < 60ml/min/1.73m2 ,remaining nephrons are vulnerable to hypoxic injury,as they are at increase need of oxygen.
  22. 22. Cytotoxic effects on renal tubular cells  Hardick et al – effect on apoptosis was not found ,proliferation impaired. – reduced proliferation will affect renal function with a delay of hours – clinical course of CIN.  “Vacuolization” of cells -morphological hallmark, rather than an indicator of damage.  Perturbation of mitochondrial enzyme activity – increased adenosine.  Depends on ionicity,molecular structure.  Ionic compounds –most profound effect.  Apoptosis induced in distal tubule – polarity of cells affected,opening of intercellular junctions.
  23. 23. Reactive oxygen species  O2(- ),OH- more reactive than H2O2.  “superoxide theory”  Endothelial dysfunction  Tonic influence of NO in renal microvasculature is impaired.  Superoxide rapidly scavanges NO –attenuation of NO activity.  Increased in diabetic nephropathy.  ROS – extracellular signalling molecules – mediates AT II, TXA2,ET1,adenosine,NE.  Role supported by allopurinol.  Was the background for positive role of NAC in CIN prevention
  24. 24. Adenosine  Exerts a vasoconstrictor response on afferent arteriole (A1 receptors).  A1- vasoconstriction, contracts mesangial cells in the glomerulus.  Osswald – “adenosine is mediator of TGF”.  Higher sensitivity of renal vasculature to adenosine is found in Diabetes Mellitus.  Blocking A1 receptors failed to alleviate medullary hypoperfusion and hypoxia in repsonse to contrast media.  A2A receptors increases medullary flow.
  25. 25. Endothelin  Effects of endothelin dependent on the receptor subtype activation.  ETA- vasoconstriction.  ETB – endothelin dependent NO release.  Increased endothelin concentration in plasma and urine.  Exaggerated in pts with renal insufficiency.  Unselective receptor blocker – more vasoconstriction.
  26. 26. Unselective endothelin receptor blocker ETB VASODILATION Attenuation of ENDOTHELIN Release Increased ENDOTHELIN Release ETA VASOCONSTRICTON Selective ETA antagonism is beneficial
  27. 27.  “The most accepted explanation is that contrast media causes vasoconstriction via release of vasoconstrictors, such as endothelin and adenosine, which in the presence of already compromised renal hemodynamics cause medullary ischemia. injury to tubular epithelium seems to be mediated by reactive oxygen species.” Aqeel et al ,nephrotoxicity of different contrast media,Interven Cardio clinics(3) 2014
  28. 28. Why CIN does not occur in all ?  With normal systemic and renal circulation,radiographic contrast agents does not cause renal failure,the compensatory mechanism are intact.  Renal medulla is highly vulnerable to hypoxia.  When there is a disruption of the balance between the VASODILATORS(beneficial) and VASOCONSTRICTORS (harmful),the latter predominating- renal failure occurs secondary to increased renal hypoxia. Brezis and Rosen et al,Hypoxia of the renal medulla;its implications for disease.NEJM;1995;332:647-655.
  29. 29. Is there any risk score for CIN ? Yes
  30. 30.  8,357 pts –randomly assigned to development and a validation dataset.  Baseline and procedural characteristics of the 5,571 pts in the development dataset were considered as univariate predictors of CIN (increase >25% and or >0.5mg/dl in S.Cr at 48 hrs after PCI vs baseline).  Multivariate regression analysis for idenfying independent predictors of CIN with a p value <0.0001.  Based on the odds ratio,eight identified variables(hypotension,IABP,CCF,CKD,Diabetes,Age>75yrs,anemi a,volume of contrast) were assigned a weight integer.  The sum of the integeres was a total risk score for each patient.
  31. 31. Integer – whole number ,2 for 0.5 value of OR.  The overall occurrence of CIN in the development set was 13.1 % (range 7.5% vs57.3% for a low 5 and a high ≥ 16 score, respectively).  Rate of CIN raised exponentially with increased risk score.  Good discrimative power in the validation dataset.(c statistic - 0.67).  Exclusions : Pts with pre-existing ESRD requiring dialysis and other contrast exposure within one week or less from index procedure,pts with PCI treated for Acute MI,patients in shock were excluded from analysis.  Hydration : 1 ml/kg/h of 0.45%NS for 4-12 hrs before PCI,18-24 hrs after PCI.
  32. 32. Effect of contrast volume on CIN
  33. 33. A patient with CIN requiring dialysis is at high risk of mortality Mc Collough et al.
  34. 34. CIN has impact of poor prognosis in patients with MI
  35. 35. CONTRAST MEDIA
  36. 36. Important considerations in choosing a contrast agent  SOLUBILITY  OSMOLALITY  VISCOSITY
  37. 37.  Classified into ionic and nonionic groups based on water solubility.  Ionic agents, water soluble, dissosciate into negative and positive ions, bind with negative and positive poles of water molecules.  Nonionic agents donot dissosciate,but are water soluble,polar OH groups.
  38. 38. TYPES OF CONTRAST MEDIA  Based on osmolality relative to plasma  HIGH OSMOLAR CONTRAST AGENTS (HOCM)  LOW OSMOLAR CONTRAST AGENTS (LOCM)  ISOOSMOLAR CONTRAST AGENTS (IOCM) Further classification is by contrast agent ratio No. of iodine atoms/No. of particles in solution. Most imp. factor impacting attenuation.
  39. 39.  Basic structure of a benzene ring.  Triiodinated benzene rings(2,4,6).  Iodine augments attenuation, increases the linear coefficient of radiation.  Monomers (one triiodinated ring),dimers (two).  Attachment at the first carbon atom differentiates ionic from non ionic contrast agents.  Sodium/Meglumine – ionic  Amide group – nonionic  OH groups 1,3,5 – solubility,decrease protein binding.
  40. 40. HIGH OSMOLAR CONTRAST AGENTS  Single, negatively charged triiodinated benzene ring attached to sodium or another cation, such as meglumine.  Negatively charged anion is Radiopaque.  Sodium content of the agents is equivalent to that of blood.  Inexpensive.  SODIUM ACETRIZOATE (UROKON) 1951  SODIUM DIATRIZOATE (HYPAQUE) 1956  ISOPAQUE  Side effects because of osmolality (5-8 times physiologic ) {PAIN}
  41. 41. LOW OSMOLAR CONTRAST AGENTS  Metrizamide (metrizoic acid and glucosamine, water soluble with low osmolality).  Osmolality 485 mOsm  It ppts with high temperature (sterilization)  Minimize effects related to hypertonicity.  IOPAMIDOL (Iopamiro)  IOHEXOL (Omnipaque)  IOPROMIDE (Ultravist)  IOVERSOL (Optiray)  IOBITRIDOL (Xenetix)  IOXAGLATE (Hexabrix) (6 :2) (Nausea,Vomiting)
  42. 42. advantages  Intravascular agents of choice today.  Lack of a glucose radical.  Ability to be autoclaved  Easier synthesis  Less expensive to produce
  43. 43. ISO OSMOLAR CONTRAST AGENTS  Nonionic  IODIXANOL (Visipaque) only IOCM used in the cardiac catherization laboratory.
  44. 44. ROLE OF OSMOLALITY  Effect of the osmolality on degree of apoptosis in a renal epithelial cell line using DNA fragmentation as a marker.in these experiments salt and mannitol solutions with osmolality comparable to that of HOCM did not cause much fragmentation as HOCM,suggesting a direct toxic effect on the renal epithelial cells that is unique to contrast media.  Mitochondrial dysfunction.  IOCM more nephrotoxic than HOCM,LOCM – increased viscosity and tubular hydrostatic pressures.  Greater reduction in medullary blood flow with IOCM.  Osmotic nephrosis i.e swelling and vacuolization of proximal Renal tubular cells. – Dickenmann et al..
  45. 45. Viscosity  Should have lowest attainable viscosity.  Contrast media may induce high viscosity in the renal tubules,affecting renal function (not confirmed in humans)  Lowest viscosity (High osmolar contrast agents) much more nephrotoxic .  Is of minor importance.  Dimers have higher viscosity than monomers  Ionic contrast media lower than nonionic.
  46. 46. Comparison of different osmolar agents..which is beneficial ??  Iohexol cooperative study;Rudnick et al – IOHEXOL vs DIATRIZOATE,iohexol was less nephrotoxic in patients with CKD  Diabetes.(7% vs 4% ,27% vs 12%) Kidney Intern 1995;47(1):254-61  No difference in nephrotoxicity in patients with normal kidney function,with or without diabetes.
  47. 47. IODIXANOL vs LOCM  NEPHRIC trial – diabetics,serum cr -1.5 -3.5 mg/dl (3% vs 26%) (p=0.02) iodixanol vs iohexol . NEJM 2003;348(6):491-9.  RECOVER trial – iodixanol vs ioxaglate (7.9% vs 17%,p=0.021), in pts with severe CKD (12.5% vs 53.3%),diabetics (10.4% vs 26.5%).. JACC 2006;48(5):924-30.  CARE trial – contrary findings – moderate to severe CKD pts,no difference in CIN.(6.7% vs 4.4% p=0.39) iopamidol Circulation 2007;115(25);3189-96.  VALOR trial –ioversol – (21.8% vs 23.8%). Am H J 2008;156(4);776-82.  IMAPCT trial ,PREDICT trial ,ACTIVE trial - IV studies. - no difference in nephrotoxicity.
  48. 48.  When all studies pooled together ,no difference in the risk of CIN was seen between iodixanol and other LOCM( relative risk ,0.80.P=0.1).  Better when compared with iohexol (p=0.01)  In the intravenous group,reduction in CIN risk was not found with iodixanol compared with other LOCM(RR - 1.08,p=0.79),not even in high risk patients with underlying CKD and diabetes.
  49. 49. Why iodixanol was not beneficial in all patients ??  Increased viscosity of iodixanol,resulting from its dimeric composition.  Increased RBC aggregation – stasis in renal tubules – tubular ischemia.
  50. 50.  “..it is often thought that iso osmolar contrast media are superior to low osmolar agents,since they would not increase resistance to a similar extent”---- NOT TRUE - ? OSMOLALITY PLAYS NO ROLE FOR BLOOD FLOW WHILE VISCOUS PROPERTIES ARE DECISIVE.  Q =  P    r4 /  8  l  Monomeric contrast media - higher viscosity – decreases medullary blood flow – decreased p02 levels.  …..not only the intrinsic viscosity of fluid is important but also their interaction with blood constituents. High osmolar agents – diminish erythrocyte deformability – increases stiffness – difficulty to pass through capillaries – trapping in vasa recta.
  51. 51.  Adverse effects if augmented fluid viscosity by the use of dimeric contrast media may be more pronounced in renal tubules than in capillaries.  Dimeric contrast media -  viscosity -  flow -  resistance  40 mm Hg  markedly towards the distal section of kidney due to fluid reabsorption  Urine becomes concentrated Tubular fluid viscosity increases Tubular plugging Hydration attenuates fluid reabsorption
  52. 52.  Dimeric contrast media should be prewarmed before infusion;since they markedly reduces viscosity.
  53. 53. NON RENAL COMPLICATIONS OF CONTRAST AGENTS
  54. 54. PREVENTIVE MEASURES
  55. 55. Four basic concepts  1.hydration and volume expansion  2.choice and quantity of contrast material (IOCM or LOCM)  3.pre,intra,post procedural end organ protection with pharmacotherapy.  4.Post procedural monitoring and expectant care. (24-48 hrs post procedure s.creatinine),(dialysis need in patients with eGFR<30ml/min/1.73m2)
  56. 56. HYDRATION  Simplest and most effective way of protecting renal function.(decreases by 50% chance of CI-AKI)  Effect of contrast agents on kidney is prolonged in dehydration.(RBF,GFR).  0.9% NS by IV infusion at a rate of approx.  1-1.5ml/kg/hr.(adjust accordingly).  Atleast 300-500ml of IV hydration before administration of contrast material.  6-12 hr before the procedure and continued for upto 12-24 hr after the radiographic examination,if diuresis is appropriate.  Urine output 150ml/hr.(if more – replace the lost fluids)  Eisenberg et al .  Solomon et al (CKD pts -0.45% NS). *AJR 1981;136:859-861. ^NEJM 1994;331:1416-1420.
  57. 57. Oral or IV?  Only about 2/3 pts receive hydration as per the guidelines.  Three times more water required compare with isotonic sodium solutions to produce the same expansion of the extracellular space.(60% vs 20%)  Even in the euvolemic state,administration of a sodium load decreases sodium reabsorption in the proximal tubule and loop of henle and increases urine volume.  Increased GFR –increases clearance of CM- diminish duration of renal tubular cells exposure to CM.  Oral intake of NaCl or water may be equally protective as IV fluids for prevention of CIN.
  58. 58. When before/during/after procedure?  Administration of fluid immediately before or at the time of CM exposure is less efficacious for prevention of CIN.  Sufficient time to increase urine output,decrease vasconstrictive forces,replete extracellular volume are required for optimal protection.  6 hrs -12 hrs before procedure,12 hrs -24 hrs after procedure.
  59. 59. NaHCo3 or NaCl ??  Merten et al.119 pts  2 cohorts,IV solution 154 mEq/L(3ml/kg 1 hr before,1.5ml/kg/hr during,for 4hrs therafter)  NaHCo3 superior to NaCl  Rates of CIN (1.7%,n=1 vs 13.6%,n=8)  Free radical formation (acidic environment) can be inhibited by increasing the pH of normal extracellular fluid,with use of bicarbonate.  NaHCo3 – effective and safe alternative to Normal saline.  BOSS (Bicarbonate or Saline Study) TCT 2013,no difference in the incidence of CIN in pts with CKD 3b,4,5 undergoing CAG,PAG.  Veterans affairs trial – role of NaHco3 –definitive answer.
  60. 60. Imp. note “Despite the fact that no controlled randomized trial with sufficient statistical power has been rigoursly performed to prove the benefit of hydration as scientific fact, it is almost universally accepted as an appropriate and safe measure to prevent contrast induced nephropathy…” Gleeson and Bulugahapitiya et al AJR2004;183:1673-1689
  61. 61. N-Acetyl cysteine  Reactive oxygen species have a role in renal damage caused by contrast agents.  Thiol containing antioxidant.  Proved beneficial in acetaminophen poisoning.  Free radical scavanger or a reactive sulfhydryl compound increasing the reducing capacity of the cell.  S- nitrosothiol,stable and potent vasodilator.(peroxynitrite production is limited).  Improves the expression of NO synthase,improves blood flow.  blocks expression of VCAM-1,NFKB in glomerular mesangial cells.
  62. 62. Literature on role on NAC in CIN prevention  NAC – 1200 mg/day,given orally in divided doses on the day before and the day of administration of the contrast agent,beneficial in CKD pts - Tepel et al .*  APART trial #  Durham et al – negative results (intra arterial,high dose of contrast)(1200 mg 1 hr before ,and then 3 hr afterward).²  Allaqaband et al – (1.6 mg/dl ,Cr Cl <60ml/min).  Goldenberg et al -600 mg tid,increase in serum creatinine (10% vs 8%)  ACT trial-no benefit. *Prevention of contrast induced reduced renal functions by NAC ,NEJM 2000;343:180-184 #APART trial – Am J Cardiol 2002;89:356-358. ²NAC in CAG ptsKidney International2002;62:2202-2207 Goldberg et al – EHJ 2004
  63. 63. Imp note.  NAC reduces the occurrence of contrast induced nephropathy after nonionic contrast medium administration by half in high risk patients.  Seven trials,805 pts  NAC +NS reduced the relative risk of CIN by 56%(p=0.02).  No trial to date has investigated the effect of NAC on hard clinical end points such as in hospital morbidity rates,mortality rates,or dialysis dependency.  Combats cardiovascular disease (40% lower ) Birck et al. Birck et al ,Lancet 2003;362:598-603
  64. 64. An oral dose of 600 mg twice daily the day before and the day of procedure is the most commonly used regimen. IV doses of 150mg/kg over half an hour before the procedure or 50mg/kg administered over 4 hrs(critically ill pts) 1200mg >>>> 600 mg +NS Briguori et al High dose contrast use group benefited significantly from preprocedural NAC (18.9 %vs 5.4% ,p=0.04)
  65. 65. Does NAC have deleterious effects on its use??
  66. 66.  Results of the ACT study have been considered in most of the current guidelines,donot support the use of this drug as preventive measure of CI-AKI.  Result of the PRESERVE trial are awaited.
  67. 67. Recommendations for NAC
  68. 68. Why there are conflicting results ??
  69. 69. Ascorbic acid  Potent water soluble antioxidant  Scavanges reactive oxygen compounds.  Increases NO availability,alkalizes the urine.  Sadat and colleagues et al,meta analysis – ascorbic acid beneficial in patients at risk of CIN.
  70. 70. ASCORBIC ACID
  71. 71. Diuretics  Beneficial in animal studies but not in humans.  Anto et al – mannitol beneficial 250 ml 20%/hr with hydration before and after procedure –(22% CIN in Rx group,70% NS group)  Solomon et al – exacerbation of CIN on use of furosemide or mannitol.  Weinstein et al –worsening of renal function  Weisberg et al – no protective effect. 1.Arch Internal Medicine,1981;141:1652-1656. 2.NEJM,1994;331:1416-1420 3.Nephron 1992;62:413-415. 4.Kidney Int 1994;45:259-265
  72. 72. ANP  Increases GFR,glomerular hydrostatic pressure by dilating afferent arterioles and constricting efferent arterioles,while blocking tubular reabsorption of sodium and disrupting the tubuloglomerular feedback mechanism.  The Auriculin Anaritide Acute Renal Failure Study Group,multicenter,randomized,double blind placebo controlled trial. – detrimental effect of anaritide in oliguric patients  Lewis et al –significant drop in BP in anaritide group.  Kurnik et al – detrimental effect.
  73. 73. Calcium channel blockers  Role of calcium as a mediator in CIN.  Neumayer et al – Nitrendipine. (Beneficial)  Solomon et al – no benefit (78 pts).  Khoury et al – Nifedipine10 mg,administered 1 hr before imaging made no statistically significant difference in renal function.  Larsson et al – no benefit of felodipine in diabetics.  Failed to gain as a prophylactic tool to date.
  74. 74. Adenosine antagonists  Adenosine, a potent vasoconstictor agent, mediator in TG feedback.  Theophylline  In the wake of a lack of consensus in clinical studies,coupled with potential side effects of theophylline ( such as a propensity to cause arrhythmias and convulsions),narrow therapeutic index,adenosine antagonism cannot yet be recommended for routine prophylactic use in the current clinical setting.
  75. 75. Dopamine agonists  Potent vasodilator of the renal arteries.  Hans et al – dopamine infusion of 2.5ug/kg/min ,during and after procedure – small improvement in renal function (n=60).  Recent reports failed to show the benefit of dopamine,instead it prolonged the duration of CIN.  Allaqband et al –Fenoldopam(selective dopamine 1 agonist,6 times more potent) – no additional benefit.  No longer recommended for CIN prophylaxis.
  76. 76. Hemodialysis or hemofiltration  Removal of contrast media by hemodialysis after procedure in patients with preexisting renal failure,no effect on CIN,and is unwarranted as a routine procedure.  Vogt et al –hemodialysis vs IV hydration  Hemofiltration beneficial than hemodialysis – Marenzi et al – hemodynamic stability,preserved blood volume,preventing hypoperfusion.  Relatively high cost. Vogt et al,Am J Med 2001:111:692-698. Marenzi et al ,NEJM 2003;349:1333-1340.
  77. 77. TRIALS IN CIN  APART trial  REMEDIAL trial  ISLAND trial  RECOVER study  CARE study  MEENA trial  P.R.I.N.C.E study  PREPARED  MYTHOS  PROMISS  ARYMDA CIN  ACT trial  PRESERVE trial  BOSS study
  78. 78. CONSENSUS STATEMENTS IN CIN
  79. 79. KDIGO guidelines for CIN  CIN be defined and staged according to the KDIGO recommendation for the definition of AKI.  Individuals who develop changes in kidney function after administration of Intravascular contrast media should be evaluated for CIN and other possible causes of AKI.  Risk for CIN,screen for pre existing CKD.  Alternative imaging methods should be considered at increased risk of CIN.  Lowest possbile dose of contrast medium to be used.  IOCM or LOCM to be used.  Doesnot specifically comment on preferential aviodance of iohexol in patients at high risk of CIN.  IV volume expansion with NS or NaHCO3 solutions,use of oral NAC in patients at risk of CIN.
  80. 80. ACCF/AHA 2012 updated guidelines for UA/NSTEMI  Donot recommend the use or avoidance of any particular IOCM or LOCM in view of the inconsistent relationships between the various contrast agents and CIN.  Recommend adequate hydration before angiography,choice of fluid no preference.  Benefit of NAC as an adjunct to hydration ,no recommendation on the use of NAC.  Contrast media to be less than 30 ml for a diagnostic and less than 100 ml for an interventional procedure.  Advantageous of >10 days between the first and second contrast contact if CIAKI has occurred with first procedure.
  81. 81. Is your patient being posted for Angiography /PCI???? Have a check in prescription of these drugs…… They need to be stopped ….
  82. 82. DOSES
  83. 83. RECENT TRENDS IN CI-AKI
  84. 84. STATINS…does they have any role???
  85. 85. Comparison of NAC,Ascorbic acid, Statins
  86. 86. PRACTO ACS  Consecutive statin naïve NSTEACS pts scheduled to undergo CAG  Randomly assigned 40 mg rosuvastatin on admission,20mg/day(n=252) or no statin treatment (n =252).  The incidence of CI-AKI was significantly lower in the statin group than in controls (6.7% vs 15.1%,p=0.003). JACC,63;1.2014:71-9
  87. 87. Role of heme oxygenase
  88. 88. Future  The risk of CIN may increase upto 40%,in high risk pts with every additional 5 ml of contrast media used. AJM 1990.  One source for mitigation of largely wasted contrast volume is attributable to excess coronary ostial reflux.(60% contrast injections).  A device designed to attenuate the loss of contrast caused by reflux by altering the contrast injection pressure profile  AVERT clinical trial (NCT 01976299).  Automated injection systems beneficial ?? - <3% reduction in contrast volume – GURM et al. JACC 2013.
  89. 89.  Dual contrast detection/aspiration system (Catharos Medical Systems,Los Gatos,USA).  CINCOR removal system (Osprey Medical,USA)  Automated balance hydration (Renal Guard system).  REMEDIAL trial – 11.05 % vs 20.5% ,p=0.025,score >11  MYTHOS trial - 4.6%vs 18.0% (p=0.05),CKD 3 or more  CIN-RG trial – underway.  Renal cooling- COOL RCN trial -effect of systemic hypothermia in prevention of CIN-no benefit. AJC 2011.  Intra renal drug infusion –Fenoldopam – no benefit in CIN.  REMOTE ISCHEMIC CONDITIONING –beneficial . Circ 2012
  90. 90. KEY POINTS  The risk of contrast induced nephropathy is directly proportional to the severity of pre existing renal insufficiency.  Hydration with NS is the most widely accepted preventive intervention.  Statins use,lower incidence of CIN (best pharmacological strategy for prevention).  N-acetylcysteine may be effective,but studies have given conflicting results.  Sodium bicarbonate may be of value,but larger multicenter studies are needed to determine its true effectiveness.
  91. 91.  Newer contrast agents that are nonionic and of lower osmolality than older agents are less nephrotoxic, but still can cause nephropathy.  Hemofiltration – large RCTs should be performed before recommended as standard prophylaxis against CIN in high risk patients.  Theophylline cannot be recommended as standard prophylaxis against CIN.
  92. 92. TAKE HOME MESSAGE  Better markers for CIN are needed in near future,taken the disadvatanges of serum creatinine.(cystatin C,NGAL,KIM,IL-18)  Adequate hydration is important in a patient being posted for CAG,PCI, especially those with risk factors.  IOCM or LOCM to be used in patients at high risk of CIN, but not to use iohexol or ioxaglate if LOCM were to be used.  Contrast volume to be confined to less than half of the GFR of patient.  CIN occurrence assosciated with increased morbidity and mortality.  Role of pharamocological agents need further studies.
  93. 93. KNOW PREVENTION , NO CIN NO PREVENTION, KNOW CIN Finally…. A small quote
  94. 94. The perfect balance

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