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Aspects of Kidney donation

Created: 23/5/2005

 

Aspects of Kidney donation

  • 2004 27% of all transplants in USA were from living donors
  • Wide variations throughout world
  • Reflect differences in medical and cultural values
    • Spain <5% transplants are living donations
    • Europe <10%
    • Japan living donation is most common (cultural and legal barriers)

Living donor

  • Steady increase in number of kidney transplants per year
  • Number of deceased donor kidneys remained at a similar level (despite efforts to increase the number)
  • Longer duration on dialysis increases patient morbidity and survival
  • Resulted in an increase in living donation- lead to a change in demographics of kidney donors
  • 1st living donor transplant on ID twins without immunosuppression
  • Well-matched living-related donors then used
  • Perfect match related donors better graft survival than lesser matched related donors
  • NB graft survival in non-matched related donors is only marginally less good
  • NB survival from living-unrelated donors > well-matched deceased donors
  • 25% of living donor transplants in USA are not biologically related

Evaluation of living kidney donors

Evaluation aims to provide best organs for transplantation

  • Is donor at higher risk from procedure than expected?
  • What are risks of cancer or infectious disease transmission or risks of early graft loss?
  • What are risks of developing problems from a solitary kidney?

Aspects of Consent

  • Undergoing evaluation is not a commitment- can withdraw at any time
  • May be turned down
  • Evaluation performed by someone with donors best interests, info is confidential
  • Will be tested for AIDS, hepatitis other infectious diseases
  • Tests may have risks and have implication for future health
  • May require long-term follow-up after donation
  • There are other options for recipient apart from donor’s kidney

Essential Aspects of Evaluation

  • History and examination
  • Family history- SLE, polycystic kidneys, glomerulonephritis, Allport syndrome
  • Psychological evaluation
  • BMI, BP, FBC, clotting, chemistry, urinalysis, BM, cholesterol
  • Creat clearance/measurement of GFR
  • 24hr urine for protein
  • ECG, CXR
  • Viral serology
  • Renal imaging

Optional

Performed to evaluate abnormalities in above tests or age-history appropriate screening

  • Echo, Exercise TT
  • Colonoscopy, mammogram, PSA, cystoscopy
  • Glucose TT
  • TB testing
  • Infectious disease screening if endemic exposure (eg malaria)
  • 24hr urinary albumin, renal biopsy

Anatomical evaluation of donor kidney

  • Is nephrectomy safe to perform?
  • Which kidney?
  • Which technique?
  • Spiral CT usually employed
  • Left kidney usually chosen because renal vein is longer
  • If multiple arteries on left and one on right, right chosen

Contraindications to donation

Absolute

  • Cognitive deficit, psychiatric disease
  • Drug/ETOH abuse
  • Renal disease (eg low GFR), abnormal renal anatomy, recurrent/bilateral stones
  • Collagen vascular disease
  • DM, hypertension, mod-severe pulmonary disease, previous MI/IHD
  • History of Ca/familial history of RCCa
  • Current neoplasm (unless in-situ cervical, colon, non-melanoma skin cancer)
  • Active infection, chronic active viral infection (hep B/C, HIV)
  • Liver/neurologic disease
  • Anticoagulants, pro-thrombotic disease, pregnancy

Relative

  • ABO incompatibility
  • Age <18 or >65
  • Obesity BMI >35
  • Mild high BP
  • Single episode renal colic
  • Borderline urinary abnormalities
  • Young donor with >1 1st degree relative with DM/renal disease
  • Smoker (should stop 8 weeks before op)
  • Jehovah’s witness

Risks of donation

  • Mortality <0.03%
  • Re-op/re-admission rate 1%
  • Pneumonia/pneumothorax 9.1%
  • Wound infection, DVT/PE ˜ 3%
  • Hypertension 15%
  • CRF- 0.04% of 48,000 living donors required transplant between 1987-2001 UNOS (NB mostly siblings), long-term F/U data ˜0.3% (lifetime risk of CRF ˜2%)

LIVING DONOR NEPHRECTOMY

Techniques: Open nephrectomy

Advantages

  • Long-term safety record
  • Less equipment requirements
  • Retro-peritoneal approach minimises abdo complications
  • Shorter op time
  • Minimal warm ischaemia time
  • Excellent early graft function

Disads

  • Post pain
  • 6-8 weeks off work
  • Surgical scar

Techniques: Laparoscopic nephrectomy

1st performed by Ratner and Kavoussi 1995

USA 2003 70% of living donor transplants

Advantages

  • Less post-op pain
  • Minimal scarring
  • Shorter hospital stays (Barry 2005 BJUInt)
  • Rapid return to work
  • Magnified view of renal vessels

Disads

  • Impaired early graft function
  • Graft loss/damage during learning curve
  • Pneumoperitoneum may impair compromise renal blood flow
  • Longer op time
  • Tendancy to have shorter renal vessels and multiple renal arteries
  • More expensive
  • Slight increase in donor mortality

Post-nephrectomy issues

  • Renal function:
    • GFR increases to 15-80% of previous 2 kidney value (days to weeks)
  • Pregnancy:
    • No deleterious effect on fertility/course of pregnancy
    • No increased risk of pregnancy associated renal complications
  • Long-term medical care
    • Not much different from general population
    • Persons with mild hypertension, obesity, stones may benefit from regular F/U
    • Should avoid high-protein diets, nephrotoxic drugs

Controversies

  • Biologically unrelated donors
    • Numbers are increasing
    • Usually emotionally related eg spouse
    • Situations where Donor is unrelated needs careful scrutiny (eg illegal payment, coercion) - Well-developed protocols exist which identify such cases but may probably occur with higher frequency than recognised
  • Paid donation
    • generally prohibited, however money paid to donors can improve quality of life and donors are entitled to use body as they see fit
    • NB Studies of transplants from paid donors show higher rate of unconventional complications and deterioration in donor health after procedure
  • Transplant recipient registry exists but currently no register exists for donors

CADAVERIC/DECEASED DONOR KIDNEY TRANSPLANTATION

  • Annual number of potential brain-dead donors in USA ˜ 10500-13800
  • Consent rate 54%
  • Conversion rate 42%
  • NB Spain has most effective organ recovery service- paid personnel at trauma centres to approach bereaved families and presumed consent for donation
  • Donors tend to be brain-dead cadavers whose hearts are still beating eg head trauma, vascular catastrophies, cerebral anoxia, non-met brain tumours

Events preceding donor transplantation

  • Identify potential donor
  • Inform procurement organisation
  • Diagnosis of brain death made
  • Donor suitability ascertained
  • Family consent obtained
  • ABO/tissue typing performed
  • Kidneys removed and stored
  • Top recipient selected
  • Transplant program reviews cases of recipients of marginal kidneys
  • Recipient admitted to hospital
  • Back-up recipient prepared if recipients panel-reactive antibodies are high
  • Donor lymph and recipient serum cross-matched
  • Pre-op Hx, examination, routine tests
  • Dialysis if necessary
  • Transplant performed

Contra-indications to donation

Absolute

  • Chronic renal disease
  • >70 years
  • Potentially metastasising malignancy
  • Severe hypertension
  • Bacterial sepsis
  • IVDU, HBsAg +, HIV +
  • Prolonged warm ischaemia
  • Oliguric ARF

Relative

  • >60 years
  • < 5years- increased risk of surgical complications, graft dysfunction poorly tolerated. Good results reported from paediatric en-bloc transplantation (both infant kidneys with attachment to great vessels transplanted). If rejection avoided kidney will grow to adult size in 1 year.
  • Mild hypertension
  • Treated infection
  • Non-oliguric ATN
  • + Hep B/C serology
  • Donor medical disease (DM/SLE)
  • Intestinal perf
  • Prolonged cold ischaemia
  • High risk behaviour

Marginal/Borderline kidneys

  • Number of older donors is increasing ˜1/3 of kidney donors >50 years old
  • 5 year graft survival of a 60 year-old donor falls by 5% per decade compared to a 20-year-old donor
  • Marginal or borderline kidney has been changed to “expanded criteria donor” (ECD) in USA
  • Terminology change introduced to increase use of kidneys that may have been discarded and to minimise cold ischaemia times
  • ECD kidneys are those with a 70% greater risk of graft failure at 2 years post-transplant when compared to ideal kidneys
  • All kidneys >60 years are ECD’s
  • Those between 50-59 are ECD’s if there was a history of hypertension, CVA was cause of death or if creatinine was raised
  • Donor biopsy can be performed to aid transplant decision- if >20% of glomeruli sclerosed graft prognosis is poor

Donation after cardiac death (DACD)

  • DACD is preferred to non-heart beating donor (NHBD)
  • DACD donors fall into 2 main categories
    • Uncontrolled: pulseless and asystolic after resuscitation attempts (infrequent in USA most common form of DACD in Europe and Japan)
    • Ischaemia minimised by IV cooling, family informed and consent obtained. Organs then recovered quickly
    • Controlled: deeply comatose, vegetative, respirator dependant
    • Treatment withdrawal is decided by family and medical team. Death pronounced after predetermined period of asystole. Organ retrieval then proceeds

Cadaveric Organ Retrieval

Principles:

  • Wide exposure
  • Each organ dissected with vasculature intact
  • No dissection into renal hilum to avoid damage and prevent delayed graft function from vasospasm
  • Cannulas placed for in-situ cooling
  • After cross-clamp- flush and surface cooling is commenced
  • Preferred sequence for multiple organ retrieval- heart/lungs, liver or pancreas and then kidney
  • Kidneys protected against ischaemia during removal of other organs by cold flush and surface cooling

Kidneys alone

  • <5% of organ donations are for kidneys alone
  • Midline incision sternal notch to pubis
  • Right colon and duodenum mobilised to expose great vessels
  • Aortic bifurcation isolated, IMA/V ligated
  • Aorta controlled above coeliac trunk
  • Exposure achieved by ligation or porta hepatis or mobilisation of left lateral segment of liver supracoeliac aorta can also be controlled in left chest behind heart
  • Ureters divided deep in pelvis conserving adventitial tissue
  • Aorta cannulated at bifurcation, proximal aorta clamped and ice-flush solution commenced
  • Kidneys mobilised (with Gerota’s intact) and removed en-bloc with aorta and cava
  • If heart to be donated, it is mobilised prior to cross-clamping and removed first
  • Kidneys are separated n slush on a back table
  • Left renal vein taken off cava with a small cuff, remaining cava is left with right kidney
  • Aorta divided longitudinally leaving renal arteries attached to aortic cuffs on each side

Kidneys and other organs

  • Liver and pancreas removal precedes kidney
  • Lower border of their dissection is cava above renal veins and aorta above SMA

Pharmacology

  • Most cadaveric donors receive large doses of steroids to decrease circulating donor lymphocytes
  • Mannitol ensures diuresis and possibly minimises ischaemic injury
  • IV a-blockers and Ca++-channel blockers before kidney manipulation may reduce rate of delayed graft function
  • Heparin is administered prior to cannula placement

Ischaemia times

  • Warm ischaemia time: time between circulatory arrest and cold storage
  • With in-situ perfusion techniques it is essentially zero
  • Kidney can function after up to 20 minutes of warm ischaemia, but delayed- or non-function rates increase markedly after this
  • Cold ischaemia: period of cold storage or machine perfusion
  • Rewarm time: time from removal from cold storage to completion of renal artery anastomosis (minimised by cooling during surgery)

Cadaveric kidney preservation

  • Cold storage: kidneys flushed, separated and placed on ice
  • Machine perfusion: kidneys flushed, separated and placed on machine which pumps cold colloid solution through renal artery until transplant
  • Delayed graft function approx 25% for cold storage up to cold ischaemia times of 30hrs (rate increase significantly after 30hrs)
  • Delayed graft function approx 25% for machine perfusion up to cold ischaemia times of 48hrs
  • NB most centres prefer cold storage with cold ischaemia times of <30hrs

Preservation solutions

  • Achieve rapid cooling and blood washout
  • Collins: high in K+, hyperosmolar and has IC-like composition to stabilise cell membranes and prvent cellular swelling
  • University of Wisconsin: importance of all components not resolved
    • Glutathione may help cellular ATP regeneration and maintain membrane integrity
    • Adenosine may provide substrate for ATP regeneration
    • Used for flushing cadaveric organs, is superior to Collins for liver and pancreas preservation and possibly for kidneys with long preservation times
  • HTK-custodial: Low-viscosity solution used for solid organs in Europe

ArticleDate:20050523
SiteSection: Article
 
   
    
                                            



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