Transplantation Flashcards
Why give a transplant instead of haemodialysis or peritoneal dialysis?
There is a survival benefit.
Improves the quality of life of patients and their family.
Financial benefits to patients, families, healthcare provider and society.
Who can get a transplant?
No real age restrictions, however, co-morbidities often prevent transplant in elderly patients.
What are the types of transplant?
Deceased heart beating donors (brain stem death; DBD).
Non-heart beating donors (cardiac death donors; DCD) - ventilator switched off and if the heart stops after a short period of time (if not then the procedure doesn’t go ahead as the organ is not fully oxygenated) then they are taken straight to theatre for removal of the organ.
Live donation (altruistic) - directed and undirected; paired donation; financially procured (illegal in most countries except Iran).
How are potential recipients assessed for a transplant?
Patients with reasonable life expectancy (>5yrs).
Make sure the patient is safe to undergo the operation:
- General Anaesthetic.
- Surgical Procedure.
- Immunosupression.
- Immediate postoperative period.
Extensive assessment process.
No survival benefit until after 3 months.
What major factors are assessed in donor recipients?
Immunology - tissue typing and antibody screening.
Virology - exclude active infection.
Assess cardiorespiratory risk (ECG; echo).
Assess peripheral vessels.
Assess bladder function.
Assess mental state.
Assess any co-morbidity/PMH which may influence transplant or be exacerbated by immunosuppression.
Independent assessment.
What are the contraindications to transplant?
Malignancy:
- Known untreated malignancy.
- Solid tumour in the last 2-5 years.
Active HCV/HIV infection.
Untreated TB.
Severe IHD, not amenable to surgery.
Severe airways disease.
Active vasculitis.
Severe PVD (unusable vessels).
Hostile bladder.
If all of these are treated and stable they can undergo transplant.
What is involved in the live donor assessment?
Physical fitness for surgery?
Enough renal function to remain independent after nephrectomy?
Anatomically normal kidneys?
Any co-morbidities? (hypertension, proteinuria, haematuria?)
Immunologically compatible?
Psychologically compatible?
Coming forward without coercion?
Which blood groups are compatible with tissue typing?
What factors are involved in tissue typing for a transplant?
Blood group.
HLA A, B & DR.
What is the importance of HLA matching?
WIthout immunosuppression, it is critical as will fail.
With immunosuppression, there is better graft survival.
However, there will be sensitisation to subsequent transplants.
What are sensitising events to foreign DNA?
Blood transfusion.
Pregnancy or miscarriage.
Previous transplant.
Lead to the formation of pre-formed antibodies to non-self antigens exposed to.
How are kidneys from deceased cardiac death donors allocated?
Firstly to paediatric recipients of any match.
Then to 0, 0, 0 mismatch (ideal match).
Then to 1, 0, 0 or 0, 1, 0 or 1, 0, 0 mismatch (favourable).
Other match (unfavourable).
What is paired donation?
A paired kidney exchange, also known as a “kidney swap” occurs when a living kidney donor is incompatible with the recipient, and so exchanges kidneys with another donor/recipient pair.
Two live donor transplants would occur.
What is desensitisation?
Active removal of blood group or donor-specific antibody by giving plasma exchange and B cell antibody depleter (rituximab).
Riskier procedure.
When would you remove a recipient’s kidney during transplant?
Never unless there is a kidney infection or big polycystic kidney.
Where are donor kidneys transplanted into?
Iliac fossa and attached to the external iliac artery and vein.
Ureter is plumbed into the bladder with a stent.
What are the surgical complications?
Bleeding.
Arterial stenosis.
Venous stenosis/kinking.
Ureteric stricture & hydronephrosis.
Wound infection.
Lymphocele.
What is delayed graft function?
The kidney takes 10-30 days to work after transplant due to acute tubular necrosis.
What is primary non-function?
Transplant never works.
What are the types of transplant rejection?
Hyperacute rejection.
Acute rejection.
Chronic rejection.
What is hyperacute rejection?
Rejection due to pre-formed antibodies.
Unsalvageable.
Transplant nephrectomy required.
What is acute rejection?
Cellular or antibody-mediated transplant rejection.
Can be treated with increased immunosuppression.
What is chronic rejection?
Antibody-mediated transplant rejection causing a slowly progressive decline in renal function.
Poorly respond to treatment.
What is the purpose of anti-rejection therapy?
Reduces activation of T cells.
Aim is to prevent host V transplant-mediated immune response.
