A New Perspective on Vascular Access
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A New Perspective on Vascular Access Presentation Transcript

  • 1. A New Perspective on Vascular Access by Steve Chen Director of Nephrology, Shin-Chu Branch of Taipei Veterans General Hospital
  • 2. Highlights in vascular access First hemodialysis: 1924 by George Haas First vascular access: 1943 Quinton-Scribner shunt: 1960 Brescia-Cimino fistula: 1966 Synthetic polytetrafluoroethylene (PTFE) AVG: 1970s Permanent tunneled cuffed indwelling HD catheter: 1980s Synthetic polyurethane AVG (Vectra): 1990s
  • 3. ShuntAVG AVF Catheter
  • 4. Access use at initiation of dialysis
  • 5. Access at initiation of HD for early referral
  • 6. Burdens in vascular access Ivan D. Maya et al: AJKD 2008 (University of Alabama at Birmingham) >20% of dialysis patients hospitalizations: access related Adjusted mortality: 40 ~ 70% greater for catheter > AV shunt Fistula prevalence: USA < Europe/Japan 75% of US patients initiate dialysis with a catheter
  • 7. Choices in vascular access Ivan D. Maya et al: AJKD 2008(University of Alabama at Birmingham)Feature Fistula Graft CatheterPrimary failure rate % 20 ~ 50 10 ~ 20 <5Time to 1st use (W) 4 ~ 12 2~ 3ImmediateNeed to intervene VL Mod HQb Excel Excel ModThrombosis rate VL Mod HInfection rate VL Mod VHLongevity ~ 5Y ~ 2Y <1Y
  • 8. Vascular access monitoring Ivan D. Maya et al: AJKD 2008(University of Alabama at Birmingham) PE: absent thrill, abnormal bruit, distal edema, pulsating swelling aneurysm (F) or pseudo-aneurysm (G) Dialysis abnormality: difficult puncture, aspiration of clots, prolonged bleeding from needle site Unexplained decrease in Kt/V
  • 9. Vascular access surveillance Ivan D. Maya et al: AJKD 2008(University of Alabama at Birmingham) Static dialysis venous pressure (DVP): Ratio of DVP to systolic BP > 0.5: inaccurate predictor Access blood flow: < 600mL/min(G) or <400-500 mL/min(F) A decrease in Qa > 33% from baseline WD paulson et al: KI 81: 132-142, 2010 Doppler ultrasound: peak systolic velocity (PSV) ratio > 2/1 Dynamic DVP and recirculation: less useful Flow and change in flow(Qa and DVP) early in a dialysis session by monthly flow surveillance: inaccurate predictor Sunanda et al: ALKD 52: 930-938, 2008 (N=176)
  • 10. AVF
  • 11. What is a successful fistula? Allon et al, KI 62: 1109-24, 2002 Caliber large enough Blood flow rate: access Qb > dialysis Qb by at least 100 ml/min to avoid vein collapse and re-circulation mean dialysis Qb: 400 ml/M (USA) 300 ml/M(Europe) 200 ml/M(Japan) Vein wall hypertrophy enough Superficial enough
  • 12. How is a successful fistula? Allon et al, KI 62: 1109-24, 2002 Experience ( >12 procedures) of the surgeon Site of fistula: primary failure rate: 66% in forearm; 41% upper arm Pre-operative sonographic vascular mapping: age, DM, race, BMI Hand exercise ? Anti-platelet agents for 3 ~ 6 W Kaufman et a, Semin dial 13: 40-46, 2000
  • 13. Pre-operative vascular mapping Allon et al, KI 62: 1109-24, 2002 Mapping with ultrasonography or venography Criteria for placement of a shunt: Minimum vein diameter: 0.25cm (AVF) Minimum vein diameter: 0.40cm (AVG) Minimum artery diameter: 0.20cm Draining vein or central vein: lack of stenosis, sclerosis, or thrombosisA change of planned surgical procedure: 31% Order of preference of vascular access to be placed: Distal F > Proximal F > Proximal transposed brachio-basilic F > Upper extremity G> Thigh G> Unusual G (Necklace, chest wall)
  • 14. Assessment of fistula maturation Allon et al, KI 62: 1109-24, 2002 Post-operative sonographic measurement at 2M: A: minimum vein diameter: >0.4cm B: Access Qb> 500ml/min A or B: 70% A+B: 95% neither: 33% Time interval for dialysis use: 2 ~ 4M
  • 15. AF fistulas: primary failure Ivan D. Maya et al: AJKD 2008(University of Alabama at Birmingham) High primary failure rate: 20 ~ 50% Steal syndrome: 1 ~ 4% Post-operative ultrasound to evaluate maturation: 4 ~ 8 W after surgery Ultrasound criteria for maturity: Fistula diameter ≧ 0.4cm Access flow ≧ 500mL/min Distance from skin ≦ 0.5cm
  • 16. Primary failure Primary failure rate : early thrombosis or failure to mature adequately (Juxta-anastomotic stenosis/Large accessory veins/Excessively deep fistula ) Primary survival ( intervention-free): time from access placement to initial intervention Cumulative survival ( assisted ) : time from access placement to permanent failure Primary or cumulative survival at 1 year: Oliver et al, KI 60: 1532-39, 2001 F > G: if primary failure excluded F = G: if primary failure included
  • 17. Effect of clopidogrel on early failure of AVFs for HD Multicenter randomized controlled trial: N= 877 Clopidogrel: 300mg loading dose/75mg/D for 6 weeks Inclusion criteria: upper extremity AVF/start HD within 6 M Primary outcome: unassisted AVF patency at 6W Secondary outcome: AVF dialysis suitability ( Use of AVF with 2 needles at Q-b ≧>300 ml/min for 8 sessions this began ≧ 120 days after AVF creation) Clopidogrel group: 37% lower risk of thrombosis(RR 0.46 p=0.018); Forearm(RR 0.53); upper arm(RR 0.89) A surprising high primary failure in both groups(61%/59%) →more than reducing early fistula thrombosis in required Dember LM et al: JAMA 299: 2164-71, 2008
  • 18. Anti-platelet agents for fistulaStudy N Intervention/Duration Thrombosis (%) Intervention ControlAndrassy et al 92 Aspirin 500mg/D x 4W 4 231974Grontoft et al 36 Ticlopidine 250mg/D x 4W 11 471985Grontoft et al 260 Ticlopidine 250mg/D x 4W 12 191998Dember et al 877 Clopidegrel 300mg/D(L) 12 192008 75mg/D x 6WDOPPS: N= 2815: aspirin to reduce significantly lower risk of final AVF failure
  • 19. AV fistulas: late failure Ivan D. Maya et al: AJKD 2008(University of Alabama at Birmingham) Late fistula failure by stenosis 60% at venous outlet 25% at arterial anastomosis 5% at central vessels A large aneurysm, rarely Thrombosed fistula requires thrombectomy with 48 Hr Primary patency rate after: 27 ~ 81% at 6M; 18 ~ 70% at 12M
  • 20. AVG: go faster!
  • 21. AV grafts: graft failure Ivan D. Maya et al: AJKD 2008(University of Alabama at Birmingham) Graft failure: ~ 80% thrombosis ~ 20% infection A large pseudo-aneurysm, rarely Underlying stenosis in most thrombosed grafts: ~ 60% Venous anastomosis 15% venous outlet 10% central veins 10% intragraft 5% arterial anastomosis
  • 22. AV grafts: graft failure Ivan D. Maya et al: AJKD 2008(University of Alabama at Birmingham) Intervention-free patency after elective angioplasty: 70 ~ 85% at 3M; 20 ~ 40% at 12M Intervention-free patency after thrombectomy: 33 ~ 63% at 3M; 10 ~ 39% at 6M Stents may prolong patency in selected grafts: elastic lesion No clear advantage of bovine or cadaveric human vein grafts over PTFE grafts Polyurethane grafts (Vectra): can be cannulated within 24 Hr
  • 23. Vascular access stenosis: VNH Ivan D. Maya et al: AJKD 2008(University of Alabama at Birmingham) VNH: venous neo-intimal hyperplasia (SMC + micro-F + microvessels) Hemo-dynamic turbulence: an shear forces Dialysis needle injury Surgical vascular damage PTFE Uremia Vascular damage from angioplasty Expression of genes for cytokines Local anti-proliferative drug delivery system: Human study in progress
  • 24. Preventive strategy for VNHStrategy Mechanism of action Used in AVFmodelMechanical design Tapered graft and pre-cuffed graft geometry at anastomosis Y Deculluarized xenograft elastic mismatch between graft/vessel YBiological reagents Antisense ODNs inhibit DNA transcription N Decoy(E2F) inhibit cell cycle progression Y Gene transfer VEGF promote endothelialization N C-type natriuretic peptide inhibit proliferation via cGMP Y Cell based therapy Endothelial progenitor cells promote endothelialization of graft surface Y Endothelial cell implant promote endothelial function YSmall molecule drugs Rapamycin inhibit protein translation Y Paclitaxel inhibit mitosis by stabilizing microtubules Y Dypiridamole inhibit phosphodiesterase activity Y Imatinib inhibit PDGF receptor activity NIrradiation induce DNA damage YODN: antisense oligonucleotide Li Li Christi et al: KI 74 1247-61, 2008(University of Utah, USA)
  • 25. Catheter: fastest!
  • 26. So think twice… 26
  • 27. Catheter-related bacteremia (CRB) N Per 1000 GPC catheter-daysKairaitis 105 6.5 100%Bethard 387 3.4 84.5%Saad 101 5.5 67.4%Cuevas 189 1.54 84%
  • 28. Definition of CRB Public Health Agency of Canada Definite CRB diagnosis: 1> blood cultures from both catheter lumen and a peripheral vein grow the same organism 2>Colony count in catheter (C) ≧ 5 ~ 10X colony count in vein (V) or C ≧ V, 2 Hours earlier False positive diagnosis: colonization if from only one lumen
  • 29. Diagnosis of CRB Probable CRB diagnosis: ≧2 positive blood culture ( blood culture/catheter tip:+/- or -/+ ) + no evidence of a source of infection other than catheter Possible CRB diagnosis: negative or single blood culture + no evidence of a source of infection other than catheter , but fever ↓after catheter removal Catheter culture( positive ): CRB 63%
  • 30. Catheter-related bacteremia (CRB) Similar rates but different average time tunneled: 1/1000 catheter-days non-tunneled: 1.54/1000 catheter-days (p=0.98) Cuevas et al, JASN 1999 tunneled: 66.2 days non-tunneled: 20.6 days 35% of patients within 3 months 48% of patients within 6 months
  • 31. Risk factors for CRB Femoral route Duration of catheter use ( FVC: 5D; JVC: 3 ~ 4W) Nasal/skin colonization with S.A. Poor personal hygiene: Povidone-iodine/Mupirocin over exit site of catheter Use of occlusive transparent dressing DM Immuno-suppression Low albumin; high ferritin
  • 32. Complications of bacteremia Mortality: 8 ~ 25% Recurrence: 14.5 ~ 44% Endocarditis: mortality 30% Epidural abscess Purulent pericarditis Septic arthritis or osteomyelitis Septic pulmonary emboli Liver abscess Endopthalmitis
  • 33. Use rate of HD permanent catheter < 10% NKF-K/DOQI guidelines
  • 34. CQI process to reduce catheter rates in incident patients: a call to action1. Discuss with referral sources aboutcriteria for referral: GFR≦ 30 ml/min2. Refer patients and family to educational classes about treatment options that should include PD, transplantation, etc: GFR ≦ 20 ml/min3.Explicitly discuss with patients and family the need for a permanentaccess at a GFR ≦ 20 ml/min4.Track success of surgical outcomes by surgeon Refer back to surgeon in 6-8 weeks if fistula is not maturing5.Provide full disclosure of catheter related risks to patients and familywho refuse surgery for permanent access6.Weaning of a medi-alert bracelet to protect one arm from veni-puncture7.Classify requests to hospitals for access placement as urgent RM Hakim et al: K 76: 1040-1048, 2009
  • 35. Prophylaxis of CRB Nasal mupirocin or 5-D course of oral RIF/3M: S.A. carrier (50% in HD )who have a previous catheter-related bacteremia caused by S.A. and continue to need HD catheter ongoing by IDSA: Infectious Diseases Society of America Prophylaxis of exit site colonization by mupirocin or polysporin( Bacitracin+gramicidin+polymyxin B) ointment at exit site Lock therapy: GM/Citrate; Taurolidine/Citrate
  • 36. Vancomycin plus Gentamicin in febrile HD Life-threatening infection by β-lactam resistant GPC or MRSA GPC infection+ serious allergy to β-lactam antibiotics Antibiotic-associated colitis unresponsive to Metronidazole or that is life-threatening Prophylaxis of endocarditis in high-risk Patients: Presence of central venous dialysis catheter Alternative:Vancomycin plus 3rd cephalosporin Rationale: mixed bacteremia 9.8 ~ 12.2%
  • 37. Clinical approach to (tunneled) CRB Ivan D. Maya et al: AJKD 2008(University of Alabama at Birmingham) Vancomycin/Ceftazidime or GM /Antibiotic lockNegative culture Positive culture Positive culture X 5D Fever resolve in 2-3D Fever persists Catheter(-) CNS GNB CPS Candida ECHO Stop Metastatic Catheter(+) Workup: bone Keep lock Catheter(-) Catheter(-) Anti Duration Anti: 3W Anti: 3W Fluconazole 6-8W Guidewire Consider 2W exchange ECHO/bone scan
  • 38. Catheter removal ? Non-cuffed CuffedExit site infection Yes NoTunnel infection Yes YesCatheter-related Yes S.A.: Yesbacteremia(CRB) CNS: No ? Enterococcus: Yes
  • 39. Antibiotic dosing in HD patients Systemic antibioticsVancomycin 20mg/Kg loading during last one hour ; 500 mg TIWGentamicin 1mg/Kg (maximum <100mg) TIWCeftazidime 1G TIWCefazolin 20mg/Kg TIWDaptomycin 6mg/Kg TIW Antibiotic lock: volume of solution(ml)Vancomycin/Ceftazidime /Heparin: 1.0 /0.5/0.5Vancomycin/Heparin: 1.0/1.0Ceftazidime/Heparin: 1.0/1.0Cefazolin/Heparin: 1.0/1.0
  • 40. Tunnel infection CDC guideline: Erythema, tenderness, and induration in tissues overlying the catheter + > 2cm from the exit site Public Health Agency of Canada: Definite: 1> Purulent discharge from tunnel 2> Erythema, tenderness, induration(2/3) at tunnel with a positive culture from serous discharge Probable: Erythema, tenderness, induration(2/3) at tunnel with serous discharge, but negative culture /no discharge, but lack of alternative Possible: Erythema, tenderness, induration(2/3) at tunnel , but
  • 41. Careful observation needed for tunnel infection !
  • 42. Exit site infection CDC guideline: Erythema, tenderness, and induration or purulence in tissues overlying the catheter within 2cm from the exit site Public Health Agency of Canada: Definite: 1> Purulent discharge at exit site 2> Erythema, tenderness, induration(2/3) at exit site with a positive culture from serous discharge Probable: Erythema, tenderness, induration(2/3) at exit site with serous discharge, but negative culture /no discharge, but lack of alternative Possible: Erythema, tenderness, induration(2/3) at exit site , but alternative cause cannot be ruled out
  • 43. Watch out the signs of AVGinfection!
  • 44. AVG infection 30-day infection rate: 6% Risk factors: femoral route poor hygiene repetitive cannulations perigraft hematoma formation prolonged postdialysis bleeding from graft repeat surgical revisions HIV status(30%), DM, low albumin, high ferritin transient bacteremia from distal site or CRB
  • 45. AVG infection: S/S Local pain, irritation, tenderness Redness, warmth Diffuse or local swelling Skin breakdown Serous or purulent discharge Leukocytosis, fever
  • 46. Sub-clavian vein obstruction CVC placed for > 2 ~ 3 weeks: 40 ~ 50% If infected: 75% PTA+/- stent Veno-venous bypass surgery Access ligantion
  • 47. Antibiotic-heparin lock therapy If Vancomycin: 2.0 mg/ml; Ceftazidime: 2.0 mg/ml plus heparin 5000IU/ml, each concentration > 100µg/ml will persist > 21 days. Cefazolin, Vancomycin: 10mg/ml; Ceftazidime, Ciprofloxacin: 10mg/ml; Gentamycin: 5mg/ml No benefit to UK instillation as an adjunct to antibiotic lock
  • 48. Antibiotic lock: indications Catheterretained during an episode of catheter-related bacteremia O’Grady et al, MMWR Morb Mortal Wkly Rep 51: 1-29, 2002 Historyof multiple catheter-related bacterremias despite optimal aseptic technique Mernet et al, Clinical Infect Dis 32: 1249-72, 2001
  • 49. Antibiotic lock: pathogen Allon et al, NDT 200490%80%70%60%50% Positive surv cx40% Persistent fever30% Success20%10% 0% GNB CNS SA
  • 50. Ideal lock solution for prophylaxis Prophylaxis of bio-film formation → CRB↓ 1> Cidal activity against a broad spectrum of GPC/GNB/Fungi 2> Low likelihood of promoting antibiotic resistant bacteria 3> Compatible with catheter material and anticoagulant agent 4> Safe if inadvertently instilled
  • 51. Potential antimicrobial lock solutions Michael Allon: AJKD 44: 2004 1st 2nd 3rd 4th 殺菌 低阻 質合安全GM 40mg/dl /Citrate OK No OK OK30% Citrate OK OK OK OK70% Isopropyl alcohol OK OK OK NoTaurolidine OK OK OK No
  • 52. CRB prevalence: per 1000 days4.5 43.5 32.5 Heparin lock 2 Antimicrobial lock1.5 10.5 0 Dogra Mcintyre Kim Nori Saxena
  • 53. CRB prevalence: per 1000 days 4.5 4 3.5 3 2.5 Taurolidine 2 30% Citrate 1.5 1 0.5 0 Betjes Weijmer
  • 54. Antibiotic lock: barriers All randomized trials: F-U for < 6M Selection of antibiotic resistant infection if longer use Systemic toxicity from leaks into circulation 10-fold lower concentration of GM: 4 ~ 5 mg/mL Economic FDA not approved