1. An Observational Study on Thrombotic Microangiopathy in Renal Transplant Recipients - A Tertiary Care Centre Experience.
Dr Sarang Vijayan
Senior Resident
Department of Nephrology
Nizams Institute of Medical Sciences

2. Introduction
Thrombotic microangiopathy (TMA) is a well documented, but rare and serious complication of kidney transplantation.
It can be the histological manifestation of many etiological factors; mainly associated with Calcineurin inhibitor (CNI) toxicity and Antibody mediated rejection (AMR).
Rarely it can be a manifestation of recurrence of disease or associated with viral infections.
TMA in post transplant patients have varied clinical course and outcome, but usually associated with poor prognosis.

3. Aim of the study
To study the clinical profile, etiology and immediate as well as long term outcome of patients with biopsy proven Thrombotic microangiopathy in transplanted kidneys.

4. Materials and methods
All post-transplant patients presented with acute graft dysfunction having biopsy proven Thrombotic microangiopathy in last three years were included.
Those patient’s baseline characteristics including native kidney disease, induction given, maintenance immunosuppression and donor details were analyzed.
The episode of TMA which led to acute graft dysfunction was evaluated in detail and patient was followed up and outcomes assessed.

5. Baseline Characteristics
Total cases (TMA)
Total transplants
percentage
All transplants 10
145
6.9
Live transplant 9 89
10.2
Deceased donor transplant 1 57
1.85

6. Membranous nephropathy
Gender
No of cases
Male 9
Female 1
NKD
No of Cases
IgAN 2
Membranous nephropathy 1
FSGS
Presumed CGN 4
Presumed CIN
Onset of TMA
No of Cases
<7 days 4
7 days – 1 month
nil
1 month – 6 months
> 6 months 2

7. Baseline characteristics
parameters
Mean SD
Min
Max
Age (years)
29.4
14.6 18 45
Duration (months)
13.4
24.6
2 Days
76 Months
Serum creatinine (mg/dl)
3.71
2.6
2.3
6.5
Hemoglobin (g/dl)
9.7
2.9
7.4
12.1
Platelet count
1.38
0.86
0.6
2.1
Baseline characteristics

8. Donor Characteristics
DONOR AGE – MEAN -45.5
< 30Y -NIL
>60 –NIL
MEAN S CREATININE
0.84 ± 0.4
DONOR GFR
MEAN GFR – 89.6 ± 44
≥ 90 -4
AGE GROUP NO
<30
NIL
30-39 2
40-49 5
50-59 3
>60
GFR NO
≥ 90 4
81-90 1
71-80 5

9. TMA - Etiology

10. DIAGN0SIS
OCCURENCE
TAC LEVELS
IV MP PE
IV IG
RITUX
ATG
TAC STOP/ REDUCE
CASE 1
TAC TOXICITY
6 M
6.84
YES 3 NO
STOPPED
CASE 2
?RECCURRENC
POD3
12.94 5 50
DECREASED
CASE 3
AMR 3M
7.83 75
500
SAME
CASE 4
POD6
7.19 4 20
INCREASED
CASE 5 6M
7.9
CASE 6
37 M
CASE 7 5M
8.11
CASE 8
POD2
CASE 9
TAC TOXICITY
76M
CASE 10
COMBINED REJECTION 8
125
150

11. Immediate Outcome

12. Final Outcome

13. MILD GRAFT DYSFUNCTION
CASE
DIAGNOSIS
FINAL OUTCOME
TIME INTERVAL TX (MONTHS)
TIME INTERVAL
TMA (MONTHS)
CASE 1
TAC TOXICITY
MILD GRAFT DYSFUNCTION 26 21
CASE 2
?RECCURRENCE
GRAFT AND PATIENT LOSS 3
CASE 3
AMR 4
<1
CASE 4
NORMAL GRAFT FUNCTION 24
CASE 5
GRAFT LOSS 9 1
CASE 6 39
CASE 7 8
CASE 8
CASE 9
TAC TOXICITY 92 16
CASE 10
COMBINED REJECTION

14. Discussion
The incidence of TMA in our study was 6.9% (10 out of 145). Other studies have also showed similar incidence ranging from 4 -14%.1,2
Most common cause of post transplant TMA identified was CNI toxicity which is the same in most recent studies.3
Thrombotic microangiopathy was more common in Live related renal transplant than deceased donor transplant unlike other studies which showed more risk in DDRT. 4
TMA in post renal transplant has poor prognosis with 70% of patients ended up in graft loss in long term.

17. Post renal transplant TMA
ACUTE CNI TOXICITY
ACUTE ABMR
Recent initiation/increase in dose of CNI
Predominant tubular abnormalities, mainly prominent vacuolations.
Eccentric vascular hyalinosis
C4d negative
DSA negative
Recent decrease in immunosuppression
Extensive arteritis usually involving entire vascular tree
Associated glomerulitis and/or peritubular capillaritis
C4d positive
DSA positive

21. References
Radha S, Tameem A, Sridhar G, Aiyangar A, Rajaram KG, Prasad R, et al. Thrombotic microangiopathy in renal allografts. Indian journal of nephrology 2014;24(1).
Karthikeyan V, Parasuraman R. Outcome of Plasma Exchange Therapy in Thrombotic Microangiopathy After Renal Transplantation. American Journal of Transplantation 2003; 3: 1289–1294
Ardalan MR. Review of Thrombotic Microangiopathy (TMA), and Post- Renal Transplant TMA. Saudi J Kidney Dis Transpl 2006;17:235-44
Young BA, Marsh CL, Alpers CE, Davis CL. Cyclosporine-Associated Thrombotic Microangiopathy/Hemolytic Uremic Syndrome Following Kidney and Kidney-Pancreas Transplantation. American journal of kidney diseases,1996;561–71.