Transplant Surgery Flashcards
Define chronic kidney disease
eGFR <60 for >=3 months
What are the top 3 causes of CKD
- Diabetic nephropathy - 34%
- HTN - 29%
- Glomerulonephritis - 14%
Why is pericarditis a complication of CKD
Caused by uraemia
Describe renal bone disease
Osteodystrophy - caused by secondary hyperparathyroidism and vitamin D deficiency
At how much greater risk are CKD patients of cardiovascular disease
10-20x
What type of diet should those on CKD abide by
- Low protein (reduces accumulation of nitrogenous waste)
- Low potassium
- Fluid intake = output + 500ml
What two principles does dialysis rely upon
- Diffusion
2. Ultrafiltration
What type of catheter is used for peritoneal dialysis
Indwelling peritoneal (Tenchkoff) catheter
What are the complications of peritoneal dialysis
- Peritonitis
2. Sclerosing peritonitis
What is an autologous fistula
Direct joining of a vein with a neighbouring artery (usually end-vein to side-artery using Brescia-Cimino technique)
What is an autologous bridge fistula
A vein and artery are joined using a separate vein graft (e.g. saphenous vein)
What is a synthetic loop graft fistula
An artery and vein are joined by a loop of graft tunnelled subcutaneously
List the sites of AV fistula in order of preference
- Radiocephalic
- Brachiocephalic
- Brachiobasilic
- Forearm loop
- Thigh loop using graft
What nerves are most susceptible to injury during AV fistula formation
- Radial
- Median
What is ‘steal phenomenon’ associated with AV fistula
Claudication symptoms due to inadequate perfusion
How is Steal Phenomenon treated
Ligation of the artery just distal to the graft (except in proximal fistulas which require bypass)
Describe Allograft
Transplant tissue from a genetically non-identical donor from the same species
Describe Isograft
Graft of tissue between two individuals who are genetically identical
Describe Autograft
Transplantation of organs or tissues from one part of the body to another in the same individual
Describe Xenograft
Tissue transplanted from another species
What criteria is used to classify donors after circulatory death
Maastricht criteria
Define the warm ischaemic time
Interval from withdrawal of life to cold organ preservation (the heart is still beating - brain stem death)
Define the cold ischaemic time
Time that the organ is removed from the body and packaged in ice for transport
What is the maximum cold ischaemic time for A) kidneys, and B) livers
A) 24 hours
B) 12 hours
What marks the start of the cold ischaemic time
Perfusion of the organs with ice-cold perfusion solution and cessation of ventilation
What does perfusion solution contain
- Impermeable solutes to minimise cellular swelling
- Buffers for pH balance
- Free radical scavengers
- Membrane stabilisers
- Adenosine for ATP synthesis
Which out of DBD and DCD has the longer warm ischaemic time and why
DCD - due to peri-arrest period of hypotension
How is warm ischaemic time categorised in DCD donors
- Primary warm ischaemic time
- Functional (true) warm ischaemic time
What is functional (true) ward ischaemic time
Commences when the SBP has a sustained (2 minute) fall <50mmHg
Who regulates live donors
Human tissue authority
What type of liver transplant is performed from adult to child
Lateral segment
What type of liver transplant is performed from adult to adult
Right hepatectomy
What complications can live kidney donors develop later in life
- HTN
- Proteinuria
What 3 matching processes are required for transplant
- ABO blood group
- HLA matching
- Antibody cross-matching
Which HLA antigen is most important in kidney transplants
HLA-DR
What immunosupression is given at the time of surgery
- Methylprednisolone 1g
- Anti-CD25 monoclonal antibody
When is the repeat dose of anti-CD25 monoclonal antibody (e.g. Basiliximab) given following surgery
4 days
Outline triple therapy maintenance immunosuppression
- Calcineurin inhibitor
- Antiproliferative agent
- Steroid (Prednisolone)
Give examples of calcineurin inhibitors
- Ciclosporin
- Tacrolimus
Give examples of antiproliferative agents
- Mycophenalate
- Azathioprine
What malignancy are transplant patients most susceptible to
SCC skin (65x)
Cause of hyperacute rejection
Due to the presence of recipient antibodies against the donor kidney
When does hyperacute rejection occur
Within minutes of revascularisation
What are the signs of hyperacute rejection
- Kidney swells and becomes discoloured
- There is clumping of RBCs and platelets, fibrin is deposited, interstitial haemorrhage occurs
How is hyperacute rejection definitely managed
Transplant nephrectomy is required
When does acute transplant rejection occur
Within 6 months
What are the two types of acute rejection
- Cell-mediated (T-cell most common)
2. Antibody mediated
How is acute rejection managed
- Steroids
2. Monoclonal antibodies
What are the most prominent changes in chronic transplant rejection
Vascular changes leading to organ ischaemia
What indications for renal transplant have the greatest risk of recurrence
- FSGS
- IgA
- MCGN
- HUS
What are the contraindications to renal transplant
- Active malignancy (must be cancer-free for 2 years)
- Active infection
- Advanced atheromatous disease
How are renal transplant vessels anastomosed
End-to-side with the external iliac vessels
Live renal donor kidneys may require end-to-end due to shorter vessels
Where is the transplanted kidney typically sited
Extraperitoneal in the RIF/LIF
What is the most common cause of delayed graft function
ATN
What is a Lymphocele
Swelling over graft with normal function
What infections are renal transplant patients susceptible to
EBV
Define fulminant liver failure
Onset of encephalopathy within 8 weeks of symptoms in a person with previous normal liver function
What incision is used for liver transplant
Mercedes or Rooftop
Define a heterotopic transplant
Transplant of unrelated organ to different site
Define orthotopic transplant
Transplant of unrelated organ to same site
