Chapter 119 Renal Transplant Flashcards
What is most common histo diagnosis deom native kidney in cats needing renal transplant
Chronic interstitial nephritis
Name 6 aspects of medical ckd management
- Fluids (sc)
- Diet modification
- Phosphate binders
- Erythropoetin
- GI protectant
- Anti-hypertensive tx
What factors are associated with worse survival after renal transplant in cats?
Cats:
- Recipient age >10 yr or >12 years
- Severity of azotaemia before transplantation
- Peri-op BP
- Intra-op hypotension
- Intra-op hypoxaemia
- Peri-op weight
Dogs:
- Age
What pre-op tests should be performed prior to renal transplant
List 7 factor that preclude renal transplantation
What complatibilty check are done between donor and recipient
And in dogs?
- Cats; Blood type + cross match
- Dogs: Mixed lymphocyte response to match major histocompatibility complex
Plus assess donor renal vasculature and parenchyma via CT angio
What pre-op interventions are performed before renal transplant (once planned to go ahead, after suitability assessment)
- Donor recipient blood type + crossmatch
- Haemodialysis if creat > 700 umol/L
- Erythropoetin (100 IU/kg SC three times/week until PCV around 30%, then once weekly)or preferably darbopoetin (6.25 ug/kg SC once weekly until PCV 25% then every other week)
- Start immunosupression:
- 1-3d pre op: Cyclosporine to reach whoe blood trough concentration of 300-500 ng/ml. Book says 1-4 mg/kg bid “Neoral”. (continued for 3 months post-op then tapered)
- Morning of sx: Pred 0.5 - 1.0 mg/kg bid (continued for 3 months post-op then tapered)
What drug can be added if suspect graft rejection?
Azathioprine 0.3 mg/kg every 3d
Adjust to maintain WBC > 3,000 cells/uL
What is preferred method for ciclosporine measurement>
Whole blood trough HPLC (high performance liquid chromatography)
What is recommended immunosuppression protocol for canine renal transplant patient?
For dogs the current recommended treatment regimen is
- 2.5 to 5.0 mg/kg Neoral PO q12h (with the goal of attaining a 12-hour whole-blood trough concentration of 500 ng/mL)
- prednisolone (1 mg/kg/d PO)
- 3 to 5 mg/kg azathioprine PO q48h
N.B. dogs donors need to be MHC complex-identical littermate
Engraftment of donor haemoatopoetic cells reported –> excellent renal graft function >5 years
Propose a GA plan for renal transplant recipient and donor
What drugs are given to minimise renal arterial spasm during transplant?
Mannitol
+- ACP
What is checked re vasculature of suitable donor?
At least 0.5cm or artery, ideally single ]
(Carrell patch if mutiple)
Which kindney is preferred for transplant and why?
L, longer renal vein
If two renal veins are present in a donor, one canbe sacreficied. What should be checked before liagtion?
Ensure uretral vein not daining into the one being sacreficed.
List 3 techniques for vascular anastomosis in renal transplant
- End-to-end anastomosis of renal artery to external iliac artery. End-to-side anastomosis of renal vein to external iliac vein (–> 12% limb complication)
- End-to side anastomisis of renal artery to aorta (proximal to caudal mesenteric artery) and renal veing to cava
- Vascular closure staples
Briefly describe vasucalr anastomosis technique in renal transplant
- Partial occlusion clamps are used to interrupt blood flow in the aorta and caudal vena cava.
- Using the previously made templates, windows are created in the aorta and vena cava that match the sizes of the renal artery and vein, respectively.
- A hole is created in the aorta with an arteriotomy clamp, and adventitial scissors are used to create an oval defect (not a slit) in the vena cava.
- The aorta and vena cava are flushed with a heparinized saline solution.
- Two sutures of 8-0 nylon are preplaced at the cranial and caudal aspects of the aortotomy site. After the donor receives its second mannitol infusion, the graft is harvested and flushed with an ice-cold phosphate-buffered sucrose organ preservation solution.
- The end of the renal artery is manually dilated, and any excess adventitia around the cut end is excised.
- The renal artery is anastomosed to the aorta using 8-0 nylon in two separate simple continuous patterns: one on the medial aspect and one on the lateral aspect of the artery.
- The renal vein is anastomosed to the vena cava with a simple continuous pattern of 7-0 silk. A back wall technique is used first to suture the portion of the renal vein closest to the renal artery
If kidney being stored prior to transplant, what is it stored in and for how long
Ice-cold phosphate buffered sucrose oran preservation solution (Inversity of Wisconsin solution = gold standard) for up to 5 hours
List 3 techniques for ureteroneocystostomy
-
Intravesicular (like w Manilla)
- A hole is made at the apex of the bladder with a mosquito hemostat, and the end of the ureter is grasped and brought directly into the bladder lumen. Tunneling of the ureter through the bladder wall is not performed.
- The bladder is everted (turned inside out through the cystotomy site), and the distal end of the ureter is excised. Periureteral fat is removed, and the end of the ureter is spatulated a distance of 0.5 to 0.75 cm using straight microvascular scissors.
- The ureteral mucosa is sutured to bladder mucosa with 8-0 nylon or Vicryl in a simple interrupted pattern. The first and most important suture is placed at the proximal end of the ureteral incision (point of the “V”). It is critical that no periureteral fat is exposed after suturing is complete because this can lead to adhesions and granuloma formation that can obstruct the ureter.
- Ureteral patency can be evaluated by cannulation of the ureter with a 5-0 polypropylene suture.
-
Extravesicular
- 1-cm incision is made on the ventral surface of the bladder through the seromuscular layer, and the mucosa is allowed to bulge through the incision.
- A smaller incision (3 to 4 mm) is made through the mucosal layer of the bladder at the caudal aspect of the seromuscular incision.
- The distal end of the graft ureter is prepared as previously described.
- The ureteral mucosa is sutured to the bladder mucosa with 8-0 nylon in a simple interrupted pattern. Proximal and distal sutures are placed first.
- A 5-0 polypropylene suture can be used to check for ureteral patency before completing the anastomosis.
- When the ureteral anastomosis is complete, the seromuscular bladder incision is apposed in a simple interrupted pattern over the ureter with 4-0 absorbable suture.
-
Extravesicular with cuff of bladder tissue
- Entire ureter and ureteral papilla are harvested from the donor and anastomosed in an extravesicular manner.39 A 2-mm cuff of donor bladder wall is isolated along with the distal end of the ureter.
- A 4-mm defect is made at the apex of the recipient bladder, and the ureteral papilla is sutured in place with 8-0 Vicryl in a two-layer pattern—mucosa to mucosa, and seromuscular layer to seromuscular layer
What 3 additional procedures are performed after renal transplant
And another in dogs - why?
- Nephropexy (to abdo wal or into musculoperitoneal flap)
- Biopsy of native kidney
- +- feeding tube
- Enteroplication in dogs. Because 25% intussusception rate
What is the difference in outcome with using live vs cadaver donors?
In people, cadaver donor –> 50% incidence acute tubular necrosis
5-30% in live donors
Describe the post-op management of renal transplant patient (7 points)
- IVFT
- Abx (inc continue clindamycin lifelong if T gondii positive)
- Keo renal values, U output (inc USG, urine creat, bun, phos)
- Blood cyclosporine values q3d
- Monitor BP (hydralazine if high)
- Monitor for post-op seizures (cause unclear, hypertension associated)
- Us if azotaemia not resolved after 3d - check for uretral obstruction - re-explore if concern
What is the cyclosporine dose for first 3 months post transplant and what is it thn reduced to?
300 - 500 ng/ml
200 - 250 ng/ml
Name a fatal side effect of cyclosporine
Haemolytic uremic syndrome
–> haemolytic anaemia, thrombocytopaenia and secondary thrombi –> deteriorating renal function
Wat is survival to discharge follwing feline renal transplant?
And MST
70-92%
MST 360 - 613 d
List potential post-op complications following renal transplant (10)
Renal dysfunction:
- Post-op seizures
- Haemolytic uraemic syndroma
- Acute allograft rejection
- Chronic allograft rejection
- Retroperitoneal fibrosis
- Calcium oxalate urolithiasis
- Ureteral obstruction
Secondary to immunosuppression:
- DM
- Infection
- Neoplasia
What are c/s if acute allograft rejection?
When does it usually occur?
What % of cats does it occur in ?
Depressed, reduced appetite, PUPD, pyrexia
Occurrs first few months post-op
13 - 26%
How is acute allograft rejection diagnosed?
- C/s
- US: increased renal size (N.B. does increase normally for 6 months after transplant), loss of corticomedullary definition, increased echogenicity. Consider contrast ultrasound
Name a rare progression of acute allograft rejection
allograft rupture
How is acute allograft rejection treated?
- Rule out infection and ureteral obstruction.
- 6.6 mg/kg cyclosporine iv over 4 hours. 1 ml cyclosporine diluted in 100ml NaCL or 5% dextrose (NOT CSL!). Light sensitive so wrap lines.
- 10 mg/kg pred sodium succinate iv bid
- IVFT
repeat cyclosporine if creat not improved in 24-48 hours
How is chronic rejection characterised
How is it recognized
gradual loss of organ function
Severe narrowing of multiple arteries and thickening of capillary basement membrane
Hwo is surgery different for stone forming cats?
Use non-absorbable suture for neoureterocystostomy
What are findings of retroperitoneal fibrosis?
Azotaemia, isosthenuria,
US = hydronephrosis without hydroureter and occassionally capsule around kidney
What % of transplant cases develop retroperitoneal fibrosis?
Any case predliection
How is it managed
21%
Males (2/3rd were male)
Tx: surgical ureterolysis
List 5 potential causes of retroperitoneal fibrosis
- Otehr autoimmune condition
- Infection
- Operative trauma
- Foreign material e.g. talc
- Insufficient immunosuppression
- Urine leakage
- Haemoarrhage
What factor was associated with higher risk of infection following renal transplant
DM
What are the 2 leading causes of death in transplant patients?
- Allograft rejection
- Infection
Whtat% of cats develop Dm post-op
How is it managed?
How does if affect mortality
13%
reduce pred, give insulin
Dm –> x2.4 higher mortality rate
What is the liekly mechanism for post-transplant neoplasia
Activation of latent oncogenic virus
What is most common post-transplant neoplasia
Lymphoma
What complications have been reported after canine renal transplant
thromboembolic disease, intussusception, infection, graft rejection, renal dysfunction, cardiac failure, neurotoxicity, ocular toxicity, hepatotoxicity, and gingival hyperplasia
