1. Renal Replacement Therapies
Dr Dana Ahmed Sharif

2. Median life expectancy on RRT by age group Median life expectancy on RRT by age group incident patient starting RRT from incident of diabetic patient starting RRT from UK renal registry data, annual report 2011

3. When to start dialysis?
1- 50 years old male with GFR 13, K 5.4, mild leg oedema otherwise well years old female with GFR 12, K: 5.2 with nausea, itching and anorexia years old female with GFR 9, K: 5.0 good urine output, BP 155/90mmHg years old male with GFR 8, K: 5.0 with tiredness

4. When to start dialysis? GFR < 15ml/min with uraemic symptoms
GFR < 10ml/min whether symptomatic or not
Refractory hyperkalaemia, acidosis, pulmonary oedema, pericarditis, encephalopathy and neuropathy ( all need urgent dialysis)
There is no clear evidence that an early start to dialysis confers a survival benefit*
Pre-emptive transplant is the treatment of choice of ESRF. Consider when GFR < 15ml/min
*RCT of Early versus late initiation of dialysis, N Engl J Med 2010; 363: , August 12/ 2010

5. Principles of dialysis
Salt Water Electrolytes Acidosis Toxins

6. Haemodialysis Largely hospital based Efficient
Requires access to circulation
Limited by staff and space

7. Haemodialysis Artificial membrane used for exchange
Extracorporeal circuit
Direct access to blood

8. Haemodialysis access
Tunnelled dialysis line
A-V fistula

9. Haemodialysis 1- Diffusion:
Diffusion of solutes between solutions across a semipermeable membrane down a concentration gradient

10. Principles of dialysis

11. Principles of dialysis
Determining factors:
- Concentration gradient
Size + protein binding of molecule removed
Permeability + surface area of membrane

12. Haemodialysis 2- Ultrafiltration:
- Water can be driven through the membrane by hydrostatic
force
- By varying the trans-membrane pressure (TMP) the amount
of water removed can be controlled

13. Haemofiltration Convection
- Flow of water + dissolved solutes (convection) down a
pressure gradient caused by hydrostatic or osmotic forces
- Rate of filtration depends on pressure gradient

14. Haemofiltration

15. Basic principles Haemodialysis
Solute removal by diffusion of substances between blood + dialysate
Fluid removed by filtration (driven by pressure gradient across membrane)
Haemofiltration
Fluid removal by filtration
Solute removal by convection of substances in filtrate

16. Haemodialysis(HD) Haemofiltration(HF)

17. Haemodialysis(HD) Haemofiltration(HF)

18. Haemodiafiltration Combines both HD and HF Set for HD with high TMP
Both dialysate and
fluid replacement
required

19. Haemodialysis- complications
Access complications:
- Thrombosis
- Infection
- Lack of access
Dialysis complication:
- Reactions (hypersensitivity, inflammation)
- Hypotension
- Haemorrhage
- Air embolism
- Cardiac arrhythmias

20. Peritoneal Dialysis

21. CAPD: principles

22. Peritoneal dialysis Partly relies on residual renal function
Home based
Ambulant
Flexible
Continuous / intermittent

23. Peritoneal dialysis- CAPD
4 x 2L exchanges a day
Each exchange takes ~ ½ - 1 hour
Complications
- Peritonitis
- Loss of membrane function

24. Automated Peritoneal Dialysis
Night time exchanges only
Convenient for people in employment

25. Peritoneal dialysis Advantages: - continuous, independence
- home based, flexible
Disadvantages:
- patient competence
- peritonitis
- membrane failure
- ultrafiltration failure
- catheter exit site infection
- sclerosing peritonitis

26. Transplantation

27. Compatibility
Blood group
HLA – tissue type
Antibodies

28. Blood group
ABO antigens are expressed on endothelial cells in the kidney
Naturally occurring anti-blood group antibodies develop at 6 months of age , possibly in response to bacterial carbohydrate antigens
The same role apply for transplantation and blood transfusions (ie blood group ‘O’ are universal donor and ‘AB’ are universal recipient)
ABO incompatible transplant are generally avoided

29. Tissue typing Class I : HLA -A and –B Class II: HLA –DR
So HLA identical donors have 0,0,0 mismatch(MM)
Whereas those pairs which share 1 HLA- A, 1 HLA –B and 1 HLA –DR have 1,1,1 MM

30. Benefits of well matched graft
Lower acute rejection rate
Better long term graft survival
Fewer subsequent anti HLA antibodies
Lower incidence of delayed graft function

31. Anti- HLA Antibodies (sensitization)
Previous mismatched organ transplant
Mismatched paternal HLA antigen in Pregnancy
Blood transfusion

32. Donor type Live donor - related - non related Cadaveric donor
- Heart beating ( brain death)
- Non heart beating

33. Medication post transplant
Immunosuppressive drugs:
- Calcineurin inhibitors (Ciclosporin, Tacrolimus)
- Antiproliferative ( Mycofenolate mofetil MMF,
azathioprine)
- mTOR inhibitors (sirolimus, Everolimus)
- Steroids

34. Complications Infections - Bacterial - Fungal - Viral – EBV, CMV
- atypical
Cancer
- Skin
- Lymphomas – PTLD ( post transplant lympho-proliferative disorder)
- Solid tumours
Metabolic
- Diabetes
- Hypertension
- Osteoporosis

35. Contraindication to renal transplant
Absolute:
1- Active malignancy, a period of 2 years of complete remission recommended for most tumors
2- Active vasculitis or recent anti-GBM disease
3- Severe heart failure
4- Severe occlusive aorto-iliac vascular disease
Relative:
1- Age: not routinely offered to < 1 yr or >75 yrs
2- High risk of disease recurrence in the transplant kidney
3- Disease of the lower urinary tract such as bladder dysfunction
4- Significant comorbidity