Post Transplant Renal Artery Stenosis

Chaken Maniyan M.D.Fellow NephrologyPhramongkutklao Hospital

Causes of post-transplant HTN

• Calcineurin inhibitors (65 - 90%)

• Corticosteroids • Largely depends on dosage

• Transplant RAS 2 – 10 % • Post-biopsy AVF Rare cause

• Chronic graft rejection • Native kidneys & pre-transplant HTN

Ponticelli Cetal.Informa Healthcare,London,UK,2007.

Vascular complications after kidney transplantation

• Arteriovenous fistula

• Pseudoaneurysm• Graft thrombosis• Transplant renal artery stenosis (TRAS)

Seratnahaei A.etal, Angiology;62(3)219-2242011

Epidemiology

• Prevalence of TRAS range1-23% in different series

• US renal data system registry à 823 TRAS among 41,867 recipients (incidence rate =1.9%)

• Usually occurs within 6 month – 2 years after KT

BrunoS,etal.JAmSoc Nephrol 2004;15:134.

Risk factor

• Technical error during harvest or transplantation

• Renal artery atherosclerosis• Neointimal hyperplasia, accelerated atherosclerosis

caused by immunosuppression• Cytomegalovirus infection

• Delayed allograft function

NataliaO.etal,SeminarVasc Surg 26(2013)205-212

Multivariate analysis of factor contributing TRAS

Audard V,Matig,etal.AmJTransplant2006;6:95.

Clinical manifestation

• Worsening or refractory hypertension

• Graft dysfunction in absence of • rejection, ureteric obstruction, or infection

• Fluid retention edema, CHF/flash pulmonary edema • Paradoxically normal or low BP• rapid deterioration of renal function after

diuretic therapy or addition of ACEI/ARB

BrunoS,etal.JAmSoc Nephrol 2004;15:134.

Presence of a bruit ?

• Not specific (physiologic vascular turbulence in the iliac or femoral arteries to anastomosis)• Bruits from proximal iliac vessel stenoses or

biopsy-induced parenchymal AVF can also confound clinical picture

• Significant stenosis can occur in absence of an audible bruit

BrunoS,etal.JAmSoc Nephrol 2004;15:134.

Differential Diagnosis

• Effect of CNI • esp early after transplantation (highest doses)

• Atherosclerotic Iliac stenosis of native vessels • accelerated by steroids and CNI

• Immunologic endothelial damage (chronic rejection)

• Thrombosed arteries of graft

W.Chen et al , Clin Kidney J (2015) 8: 71–78

Classical kidney transplantation surgery

Diagnostic procedures of TRAS

Bruno S et al. J Am Soc Nephrol 2004 ;15 : 134 – 141.

Comparison of imaging in TRAS

W.Chen et al , Clin Kidney J (2015) 8: 71–78

Renal duplex ultrasound

• Renal duplex ultrasound is valuable for making the diagnosis of transplant renal artery stenosis.• CRITRIA FOR DIAGNOSIS• Peak systolic velocities >200 cm/s• Velocity gradient >2:1• Resistive index >0.8• OR presence of pulsus parvus et tardus

waveform• Acceleration time > to 0.08 sec

Dimitroulis D,etal.Transplantation2009;41:1609–14.

ipsilateraliliacartery

tardus-parvus waveform

Pseudo-TRAS

• Iliac artery disease proximal to the anastomosis •

• Low flow to transplanted kidney • Signs & symptoms resembling those of TRAS • Claudication or other signs of limbs hypoperfusion• Treated by angioplasty or surgical revascularization

AslamSetal.Transplantation2001;71:814– 817.

Managemnt

• Untreat significant lesion of TRAS leads to graft failure and death• 3 Modalities • Medical therapy• Percutaneous intervention• Surgical intervention

W.Chen et al , Clin Kidney J (2015) 8: 71–78

Medical Therapy

• ACEI should be used to control blood pressure• In case of stable renal function AND• no evidence of hemodynamically significant

stenosis (PSV <180 cm/s and RI >0.50. • Other agents that are considered helpful for TRAS

are statins and acetylsalicylic acid

W.Chen et al , Clin Kidney J (2015) 8: 71–78

Endovascular treatment

• Indication• presence of a hemodynamically significant

stenosis (>50% on catheter angiography) • presence of >10% peak systolic pressure

gradient• Treatment options include • percutaneous transluminal angioplasty (PTA)• PTA with bare metal • PTA with drug-eluting stents

Percutaneous Intervention

• Percutaneous transluminal angioplasty (PTA) with stenting has become à treatment of choice for TRAS • decreased incidence of restenosis compared with PTA

alone (restenosis rate 10% Vs 39%)• less invasive than surgical approach

• Complications (0-10%)• Renal artery dissection,• Stent restenosis, • Thromboembolism • Hematoma• Pseudoaneurysm at the puncture site

W.Chen et al , Clin Kidney J (2015) 8: 71–78

Hemodynamic change after PTA

Ruggenenti P. et al Kidney Int 2010; 60:309.

PTA benefit

Seratnahaei A.etal, Angiology,62(3)219-224,2011

PTA lack benefit

Seratnahaei A.etal, Angiology,62(3)219-224,2011

Recanati-MillerTransplantationInstitute,IcahnSchoolofMedicineatMountSinai,NewYork,NY

BMS , DES , PTA alone what is the best

D.M.Biederman etal,AmericanJournalofTransplantation2015;15:1039–1049

• Nosignificantdifferenceinallograftsurvivalat360d

• Patency wassignificantlyhigherinwithDESandBMScomparedtoPTA

• Inpostanastomotic TRASsubtype,patencyratesinDEShighercomparedtoBMS

Surgical revascularization

• Indicated in cases of failed PTA or severe kinking or stenosis • Techniques include resection and revision of the

anastomosis, saphenous vein bypass graft of stenotic segment, localized endarterectomy and excision/reimplantation of the renal artery

• Higher rates of morbidity• graft loss and ureteral injury• mortality in up to 5% of cases

W.Chen et al , Clin Kidney J (2015) 8: 71–78

Thank you for your attention