1. Renal Unit-Careggi University Hospital-Florence-Italy
EFFICACY AND SAFETY OF PALMAZ STENT INSERTION IN THE TREATMENT OF RENAL ARTERY STENOSIS IN KIDNEY TRANSPLANTATION
Bertoni E., Di Maria L., Zanazzi M., Rosati A., Piperno R., Moscarelli L., Salvadori M.
Renal Unit-Careggi University Hospital-Florence-Italy

2. BACKGROUND I BESIDE MEDICAL MANAGEMENT, TWO DIFFERENT TREATMENT MODALITIES ARE CURRENTLY AVAILABLE FOR PATIENTS WITH TRANSPLANT RENAL ARTERY STENOSIS. AS SURGICAL REVASCULARIZATION BEARS THE RISK OF HIGH MORBIDITY OF THE GRAFT, PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY HAS RECEIVED CONSIDERABLE ATTENTION AS A NONINVASIVE TREATMENT APPROACH

3. THERAPEUTICAL OPTIONS IN THE TREATMENT OF TRANSPLANT RENAL ARTERY STENOSIS

4. BACKGROUND II
PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY HAS A PERCENTAGE OF TECHNICAL SUCCESS OF 75-88%. MAIN LIMITS OF PTA ARE BOTH THE STENOSES OCCURRING AT THE ANASTOMOTIC SITE AND THE RECURRENCE OF STENOSIS AFTER A PREVIOUS SUCCESSFUL PTA.
IN SUCH CASES METALLIC STENTS HAVE BEEN PROPOSED TO TREAT ARTERY STENOSIS.

5. AIM OF THE STUDY
AIM OF THE STUDY WAS TO EVALUATE THE EFFICACY AND SAFETY OF PALMAZ STENT INSERTION IN THE CASE OF RECURRENCE OF RENAL ARTERY STENOSIS AFTER A PREVIOUS ANGIOPLASTY OR IN THE CASE OF SEVERE ANASTOMOTIC STENOSIS

6. PATIENTS AND METHODS I
TRAS was cause of hypertension and of some degree of graft dysfunction in 26 patients out of our series of 450 consecutive cadaveric renal transplant recipients (5.7%)
All these patients were treated by the permanent insertion of Palmaz stent
15 patients had a complete follow-up of 36 months
Mean blood pressure, peak systolic ecodoppler velocity and serum creatinine were collected at predetermined time points pre and post stenting

7. Tab.I Analytical data of study patients
 A=Anastomotic site P=Post-anastomotic site
© E-S= End to side E-E= End to end

9. Tab. II Summary of patient data
N° of Patients
Gender (M/F) /11
Age at transplantation (yrs) 9.4
Type of anastomosis (end to end) 7
Type of anastomosis (end to side)
Site of stenosis (an. Vs postan.) /10
Time from transplantation (median)
Follow-up (months) 33.6

10. PATIENTS AND METHODS II
All patients with documented severe anastomotic stenosis or recurrence after PTA, were treated by Palmaz stent
TECHNIQUE OF STENT IMPLANTATION
Palmaz endoprothesis is a stainless tube crimped onto the same angioplasty balloon. The delivery system is withdrawn into the aorta leaving the stent in place mounted on the balloon. The balloon is inflated and the stent expanded. The stent is left in place, after the removal of the guide wire and balloon catheter (fig.1)

11. RESULTS I
Figg. 2 and 3 show the angiographies of pre
and post-stenting in the case of renal artery
anastomotic stenosis.
Figg. 4 and 5 show the angiographies of pre
and post-stenting in the case of post-anasto-
motic stenosis.
Figg. 6 and 7 show a typical picture of pre
and post-stenting color doppler.

12. Fig. 4 Post-anastomotic stenosis. Pre-stenting

13. Fig. 5 Post-anastomotic stenosis. Post-stenting

14. RESULTS II
Mean blood pressure as well as peak systolic velocity fell significantly after stenting (fig. 8).
Similarly the renal function improved after stenting (fig. 9).
The need of antihypertensive drugs significantly decreased after stenting (fig.10).
In the case of the 15 patients with a complete follow-up of 36 months The ANOVA for repeated measures revealed a continuous and stable improvement of such results (tab.III).
The graft survival over time documented similar survival of patients treated with stenting and patients without renal stenosis (fig.11).

15. Fig. 8 MEAN BLOOD PRESSURE
Pre-stenting
Post-stenting
***
***
***
***
***
***
***
***
mmHg
PEAK SYSTOLIC VELOCITY
***
***
***
***
***p<0.001

16. Fig. 9 SERUM CREATININE
Pre-stenting
Post-stenting * * * *
* p<0.05

17. Fig. 10. NUMBER OF HYPOTENSIVE DRUGS PRE AND POST STENTING

18. Tab. III Mean blood pressure, peak systolic velocity and serum creatinine pre and post stenting of 15 patients with a complete follow-up of three years
PRE
STENT 1
WEEK
MONTH
YEAR 3
YEARS
ANOVA p
MAP
117
6.2
101 
12.4
101.7 
7.5
103.7 
13.6
103.5 
8.4
<0.0001
V max
366.5 
62.6
128.7  41
171.9 
52.42
159.7 
70.23
152 
50.9
sCr
1.98 
0.85
1.78 
0.71
1.68 
0.72
1.56 
0.64
1.47 
0.44
<0.01

19. Fig. 11 GRAFT SURVIVAL AFTER STENTING (yellow) vs ALL TRANSPLANTED PATIENTS (red)

20. STENTING VS PTA PROS CONS EFFECTIVE IN ANASTOMOTIC LESIONS
EFFECTIVE IN RESTENOSIS
GOOD LONG TERM RESULTS IN EXPERTED HANDS
CONS
MORE INVASIVE TECHNIQUE
ARTERY KINKING NEXT TO THE STENT
INTIMAL PROLIFERATION

21. CONCLUSIONS
Our data document that in the case of severe or recurrent renal artery stenosis, the stenting of the renal artery proved to be in expert hands an effective therapeutic tool.
This method with low procedure costs and extremely low complication rate proved to be safe and to offer the potential of preserving lumen patency and so improving the long-term of angioplasty.

22. PERCUTANEOUS TRANSLUMINAL ANGIOPLASTY
PROS
LESS INVASIVE TECHNIQUE
EFFECTIVE IN NOT ANASTOMOTIC LESIONS
PROCEDURE EASILY REPEATABLE
CONS
INTIMAL LESIONS (FLAPS)
RESTENOSIS
NOT EFFECTIVE IN ANASTOMOTIC LESIONS