ORI GI N AL ARTI CLE
Endova scula r t rea t m ent of rena l st enosis in solit a r y k idne y
Ana Terezinha Guillaum onI; Eduardo Faccini RochaI I; Charles Angot t i Furt ado de MedeirosI I
IAssociate professor, Vascular Diseases, Faculdade de Ci€ncias M•dicas, Universidade Estadual de Campinas (UNICAMP), Campinas, SP, Brazil. Head, Reference Center of High Complexity in
Endovascular Surgery, Hospital de Cl‚nicas, UNICAMP, Campinas, SP, Brazil. Specialist, Angiology and Vascular Surgery and Angiographic Radiology and Endovascular Surgery, SBACV.
IIMSc. in Surgery, Faculdade de Ci€ncias M•dicas, UNICAMP, Campinas, SP, Brazil. Member, Reference Center of High Complexity in Endovascular Surgery, Hospital de Cl‚nicas, UNICAMP, Campinas, SP, Brazil. Specialist, Angiology and Vascular Surgery and Angiographic Radiology and Endovascular Surgery, SBACV. Physician, Hospital de Cl‚nicas, UNICAMP, Campinas, SP, Brazil.
Correspondence
J Vasc Bras. 2007;6(3):99-105.
ABSTRACT
Background: Endovascular treatment of hypertensive renal disease in patients with a solitary kidney secondary to renal artery stenosis proved to be effective to prevent organ failure and function, as well as hypertension control. When indicated after judicious evaluation using both biochemical methods and the patient’s images and signs, endovascular treatment has effective clinical benefits and is little invasive.
Obj ect ive: To study renal artery stenosis with hypertension and evaluate the effectiveness of endovascular treatment in the control of hypertension, renal failure secondary to renal artery stenosis, and in the prevention of renal failure in patients with a solitary kidney.
Met hods: This study was performed at the Reference Center of High Complexity in Endovascular Surgery of Hospital de Cl‚nicas da Universidade de Campinas from April 1997 through June 2005 using a previously developed protocol. Ten patients with renal artery stenosis and solitary kidney submitted to endovascular treatment were included. Improvement in hypertension and renal function was assessed through clinical follow-up and laboratory tests using measurements of blood pressure, serum urea levels, creatinine and clearance. Color-flow Doppler ultrasound was performed 30, 90, 180 days after the surgery and yearly thereafter. Aortography and selective renal arteriography were performed in case of doubt as to images or signs. For this population, 90% had hypertension, 70% were smokers, 40% had hyperlipidemia, 30% had carotid artery occlusive disease, 60% had chronic lower limb arterial occlusion, and 20% had diabetes mellitus.
Result s: Immediate success was 100%. Mean follow-up time was 40 months. Control of blood pressure occurred in 90% of the cases, and in 10% there was significant reduction in urea and creatinine levels and worsening of hypertension after the procedure.
Keyw ords: Renovascular hypert ension, st enosis, st ent .
RESUMO
Cont ext o: O t rat am ent o endovascular da doença renal hipert ensiva, em doent es com rim único, conseqüent e à est enose de art éria renal, m ost rou ser efet ivo na prevenção da falência do órgão, sua função e cont role da hipert ensão. Quando indicado após avaliação crit eriosa, t ant o bioquím ica com o por im agens e sinais do doent e, o t rat am ent o endovascular apresent a benefícios clínicos de form a efet iva e pouco invasiva.
Obj et ivo: Est udar a doença hipert ensiva renovascular e avaliar a eficácia do t rat am ent o
endovascular no cont role da hipert ensão art erial sist êm ica e da insuficiência renal secundárias à est enose da art éria renal e com o m edida de prevenção de falência renal em doent es com rim único funcionant e.
Mét odo: Est udo realizado com prot ocolo de at endim ent o previam ent e elaborado, no Cent ro de Referência de Alt a Com plexidade em Cirurgia Endovascular do Hospit al de Clínicas da Universidade de Cam pinas, de abril de 1997 a j unho de 2005, em 10 doent es com diagnóst ico de est enose da art éria renal em rim único funcionant e, subm et idos ao t rat am ent o endovascular. Foi avaliada a m elhora da hipert ensão e função renal at ravés de seguim ent o clínico e laborat orial com m edidas de
pressão art erial, dosagens séricas de uréia, creat inina e clear ance. Exam es pelo eco- color- Doppler
foram realizados no pós- operat ório de 30 dias, 3 m eses, 6 m eses e anualm ent e; no caso de haver algum a dúvida na obt enção de im agens ou sinais, foi realizada a aort ografia e art eriografia selet iva renal. Nest a casuíst ica, 90% dos doent es apresent avam hipert ensão art erial, 70% eram t abagist as, 40% , hiperlipidêm icos, 30% apresent avam doença oclusiva cerebral ext racraniana, 60% , obst rução art erial crônica nos m em bros inferiores, e 20% , diabet es m elit o.
Result ados:O sucesso inicial foi de 100% . O seguim ent o m édio foi de 40 m eses. Houve cont role da pressão art erial em 90% , dim inuição significat iva dos níveis de uréia e creat inina após procedim ent o e piora do quadro de hipert ensão em 10% .
Conclusão:O t rat am ent o endovascular da est enose da art éria renal é um a t écnica que apresent a benefícios clínicos no cont role da hipert ensão art erial, preserva a função renal e desacelera a progressão da insuficiência renal crônica de origem renovascular, porém sem m elhora dest a.
Palavras- chave:Hipert ensão renovascular, est enose, st ent s.
I nt roduct ion
Renal ischem ic disease ( RI D) , or at herom at ous renovascular hypert ension, affect s around 14% of pat ient s aged 50 years or older subm it t ed t o hem odialysis. I t has unsat isfact ory clinical course when
t here is no specific t reat m ent of renal art ery st enosis.1 Expect ed 2- year survival for pat ient s wit h t wo
kidneys and unilat eral at herom at ous disease is 97% , 82% for bilat eral disease an 45% in cases of
solit ary kidney disease.2
I ndicat ion for renal revascularizat ion due t o at herosclerot ic disease in solit ary kidney has t he following param et ers: parenchym al perfusion asym m et ry, difficult-t o- cont rol hypert ension,
progressive loss of renal funct ion and renal st enosis higher t han 60% . Thus, it is essent ial to perform a t reat m ent for renal art ery st enosis, given t hat evolut ion t o occlusion is cert ain and renal failure
to achieve im provem ent in renal perfusion when com pared wit h percut aneous renal angioplast y,6 , 7 and is oft en com prised of an associat ion of drugs t hat are unable t o m aint ain proper pressure levels. Therefore, angioplast y/ renal st ent ing in nonost ial or ost ial lesion repair is im port ant in t he t reat m ent
described in recent st udies, especially in solit ary kidneys.8 - 1 2
Percut aneous renal angioplast y was described by Grunt zig in 19781 3 and progressed wit h
im provem ent in renal assessm ent m et hods, t echnological innovat ion of m at erials, cont rast s and t echniques. I t is accept ed as a m inim ally invasive procedure, wit h low com plicat ion risks and good out com es. I t is a safe choice considering t he current and cont inuous t echnological innovat ion of m at erials, t echnical enhancem ent and low-osm olarit y cont rast s. Obt ained result s are blood pressure cont rol and preservat ion of renal funct ion.
Met hod
A ret rospect ive st udy was conduct ed at t he Reference Cent er of High Com plexit y in Endovascular Surgery ( CRACCE) of Hospit al de Clínicas da Universidade Est adual de Cam pinas ( UNI CAMP) , in 11 pat ient s wit h solit ary kidney due t o at herosclerot ic disease, subm it t ed t o endovascular t reat m ent of renal art ery st enosis from April 1997 t o June 2005 and referred by a service care prot ocol. The sam ple was com prised of 10 pat ient s. One died in t he first 24 hours due t o acut e m yocardial infarct ion and was excluded from t he sam ple because t here was no follow- up and assessm ent as proposed. This care prot ocol was subm it t ed t o appraisal by t he Research Et hics Com m it t ee so t hat t he service could be accredit ed by t he Brazilian Healt h Depart m ent and Healt h Depart m ent of t he St at e of São Paulo.
The pat ient s were referred t o t he Endovascular Surgery Out pat ient Clinic by t he nephrology service or by im age findings, considering t hat one pat ient had diagnost ic suspicion perform ed during an ult rasound assessm ent of his abdom en, which showed a cont ract ed kidney. I n 70% of cases, renal art ery lesions were ost ial, and in 30% nonost ial, alt hough all had an at herosclerot ic aspect in art eriographic im ages. Clinical assessm ent was perform ed and risk fact ors and com orbidit ies
associat ed wit h RI D were ident ified: sm oking, hypercholest erolem ia, diabet es m ellit us, hypert ension ( including inform at ion about dose and num ber of drugs used) , renal failure, peripheral occlusive art ery disease ( POAD) of t he lower lim bs, ext racranial cerebral vascular disease, and coronary disease ( Table 1) . Next , laborat ory exam s were perform ed: blood count , urine I , urea and serum
creat inine, and creat inine clear ance ; and im aging exam s, such as sim ple abdom inal ult rasound t o
The t reat m ent was indicat ed in cases of crit ical st enosis of t he renal art ery, progressive deficit of renal funct ion and difficult- t o-cont rol hypert ension, associat ed wit h presence of a solit ary kidney. I m m inent renal failure was considered when t he serum creat inine level was around 1.5 m g/ dL or
m ean glom erular filt rat ion equal or lower t han 50 m L/ m in.1 4
The endovascular surgical procedure is st art ed by an art eriography, since it helps an accurat e
locat ion of t he affect ed art ery sit e where t he st ent should be im plant ed. I n severe lesions wit h
st enosis, above 90% , or in cases of difficult progression for t he guide wire, angioplast y was
perform ed prior t o st ent im plant at ion. All pat ient s were given int ravenous heparin ( 5,000 I U) at t he beginning of t he procedure. Cont rol art eriography was perform ed by t he end of t he surgical
procedure, and t he pat ient was referred t o t he ward wit h cont rolled hydrat ion and blood pressure and m onit ored renal funct ion, and prescript ion of acet ylsalicylic acid 200 m g and clopidogrel 75 m g on a daily basis.
St enoses were defined as crit ical when larger t han 60% of t he art erial lum en, as residual when equal to 30% , and as recurrent st enosis when equivalent t o approxim at ely 50% . I n t his group, for a 40-m ont h period, t here were no recurrent st enoses, but t wo pat ient s who had already been sub40-m it t ed t o renal art ery angioplast y wit hout st ent placem ent in anot her service were adm it t ed.
During t he follow- up laborat ory exam s of urea, serum creat inine and art erial color- flow Doppler ult rasound were perform ed in t he first , t hird and sixt h m ont hs, and yearly t hereaft er.
Crit eria for clinical im provem ent were est ablished by a 20% reduct ion in serum creat inine concent rat ion and reduct ion in am ount of dose or num ber of drugs used for t he t reat m ent of
hypert ension, wit h t he aim of m aint aining diast olic pressure below 90 m m Hg. Cure was considered as presence of t hese pressure levels wit h no need of t aking t he m edicat ion, and clinical worsening was defined as a 20% increase in creat inine concent rat ion or need of increasing drug dose.
Result s
repercussion of t he organ or worsening in st enosis degree. I n t he short- and long- term follow- up of pat ent s, t here was no recurrent st enosis wit h funct ional repercussions.
Mean hospit alizat ion t im e was 3 days, and m ean follow- up t im e was 40 m ont hs. Syst olic and diast olic pressures during t he follow- up were reduced t o clinical levels wit hin t he norm al range, wit h
im provem ent in 90% of cases ( 9/ 10) and worsening in 10% ( 1/ 10) ( Figures 1 and 2). One pat ient
showed worsening of blood, syst olic and diast olic pressure in t he im m ediat e post operat ive period, but in t he lat e post operat ive period t hese were reduced t o levels wit hin t he norm al range. Anot her
pat ient s had high syst olic and low diast olic pressure aft er t he endovascular procedure in t he
im m ediat e post operat ive period, but his pressure levels increased and were cont rolled using a lower dose of m edicat ion ( lower dose and num ber of t im es) in t he lat e post operat ive period. A new im aging st udy ( art eriography) showed t here was no st enosis, which leads t o t he assum pt ion t hat t his
Blood biochem ical t est s showed t hat preprocedure urea levels ranged bet ween 36- 156, m ean 86.6,
which was reduced to 57.6 aft er t he endovascular t reat m ent (Figure 3) ; creat inine dosages in t he
Color-flow Doppler ult rasound was perform ed in t he post operat ive period showed pat ent art eries wit hout recurrent st enosis in all pat ient s. The pat ent st at us of t he art ery in t he pat ient who had worsening of diast olic blood pressure was assessed by Doppler ult rasound and also by art eriography, which did not show flow or anat om ical im pairm ent .
Discussion
Obst ruct ive renal disease in pat ient s wit h solit ary kidney has been a reason of concern due t o it s abilit y of quickly det eriorat ing t he pat ient 's qualit y of life. Considering t hat m ost organ donat ions are perform ed bet ween living donors, if som e of t hese donors have an obst ruct ive lesion of t he renal art ery t hroughout t heir lives t hey will cert ainly lose renal or kidney funct ion, wit h consequent need of
hem odialysis.1 , 3 I m provem ent in funct ional diagnost ic and im aging m et hods and increase in m ean
age of t he populat ion will m ake t his disease anot her public healt h concern, since t he survival of t hese
pat ient s is 45% in 2 years.2
This st udy aim ed at discussing renal hypert ensive disease ( renovascular hypert ension) and assessing t he efficacy of endovascular t reat m ent . This t reat m ent was applied t o pat ient s wit h difficult- t o-cont rol hypert ension, especially in t hose wit h high diast olic blood pressure, and in pat ient s wit h progressive loss of renal funct ion, det ect ed by laborat ory t est s, and t hat had a solit ary kidney. Discussion of procedure success should be perform ed considering t wo aspect s: st enosis correct ion and
preservat ion of renal funct ion. Two pat ient s had residual st enoses, lower t han 30% of t he art erial lum en, but t here was no repercussion in flow and renal funct ion during t he whole follow-up period. Use of noninvasive im aging exam inat ions, m easuring organ size and presence or not of ret ract ion areas and fibrosis, and m easurem ent s of velocit y in t he renal art ery using color-flow Doppler
ult rasound were perform ed in preoperat ive assessm ent and help diagnosis and t reat m ent prognosis. Color-flow Doppler ult rasound was perform ed in seven pat ient s in t he preoperat ive period and in all pat ient s in t he post operat ive period. There was a high resist ance level ( preoperat ive) , which m eans t hat art erial lesion is t he cause of hypert ension, and t he pat ient did not develop resist ance t o t he parenchym a, which was int act . Obt aining t he resist ance level of t he renal parenchym a using color-flow Doppler ult rasound shows t hat high level or low final diast olic velocit y m ean failure or
insignificant im provem ent in hypert ension. These dat a are in accordance wit h t he pert inent
lit erat ure.1 5 I t is im port ant t o st ress t hat in t he art ery follow- up aft er st ent placem ent t here is flow
pat ient has t wo kidneys and only one is im paired; Thus, it is a paired analysis exam . The t est wit h DMSA was used because it is an exam inat ion t hat assesses renal perfusion and excret ion, t he renal flowchart . Renal art eriography is st ill considered a gold st andard exam inat ion, since it provides anat om ical dat a of t he obst ruct ive disease and renal m orphology, ext ension and sit e, vessel diam et er and it s angle relat ed t o t he aort a.
The m ain goal of endovascular surgery is t he t reat m ent of renovascular hypert ension and/ or prevent ion of renal funct ion loss t hrough angioplast y and st ent placem ent , given t hat clinical
t reat m ent is inefficient when t he result s are com pared wit h t he endovascular t echnique.6 , 7 , 1 2 I t is
known t hat part of t he im paired and funct ionless parenchym a will not be revert ed, but aft er t he t reat m ent t he organ will present st agnat ion of funct ional im pairm ent and is, t herefore, a form of
prevent ing funct ional det eriorat ion, being part icularly im port ant in solit ary kidneys,1 0 , 1 6 , 1 7 by
m echanism s t hat have not been well defined.1 8 Unt reat ed pat ient s wit h renovascular hypert ension
will die wit hin 2 years, alt hough deat h is not at t ribut ed t o alt erat ion in renal funct ion, but t o coronary
disease.1 9 Alt hough som e aut hors st at e t hat st enosis repair im proves hypert ension and renal
funct ion,1 1 prevent ing t hese pat ient s from being subm it t ed t o a fut ure hem odialysis,2 0 it is
considered t hat t he funct ion is direct ly associat ed wit h serum creat inine serum and is, t herefore, one
of t he predict ive fact ors of im provem ent in funct ion aft er st enosis repair,1 6 a nonsignificant fact t hat
was det ect ed in t his st udy. Based on t he result s obt ained in t his series, we can claim t hat renal st enosis repair im proves art erial hypert ension and reduces renal overload, wit h consequent im provem ent in t he pat ient 's qualit y of life, alt hough t he sam ple is sm all t o generalize t he result s. There was no alt erat ion in renal funct ion or in t he anat om ical aspect of t he renal vessel in t he follow-up at 24 and 40 m ont hs; t hus, t he 24-m ont h follow -follow-up is considered as sufficient , which is in
accordance wit h ot her aut hors.1 0 , 1 1
Technical success is considered when t he pat ient shows im provem ent in hypert ension. Residual st enosis can reach up t o 30% of t he art erial lum en, considering t hat pat ient s who receive st ent s have
bet t er funct ional result s t han t hose t hat are only subm it t ed t o art ery angioplast y,1 7 according t o t he
pat ient 's long- term follow-up. I n t he 1980's repair of renal art ery st enosis was perform ed using open surgery, wit h m aj or risks, inherent t o a large-sized operat ion, and pat ient s were subm it t ed t o it under worse clinical condit ions, wit h hypert ensive disease at a lat er st age and m ore im pairm ent of t he renal parenchym a, opposed t o what current ly occurs in endovascular surgery.
Conclusion
The endovascular t reat m ent for renal art ery st enosis in pat ient s wit h solit ary kidney is a t echnique t hat has im m ediat e clinical benefit s t o correct hypert ension and preserve renal funct ion, prevent ing t he pat ient from being subm it t ed t o hem odialysis and having renal loss, but t he m echanism s for it s im provem ent are st ill cont radict ory and lit t le explained.
High resist ance level of t he renal art ery and/ or low diast olic velocit y, which can be obt ained by color-flow Doppler ult rasound, are predict ive fact ors of endovascular surgery success. I n t he long term ( 40 m ont hs) it can be st at ed t hat renal preservat ion not only im proves hypert ension and t he pat ient 's qualit y of life, but also prevent s hem odialysis, but im provem ent in funct ion st ill rem ains
cont radict ory, since reduct ion in elect rolyt es ( urea and creat inine) was int erpret ed as reduct ion in renal overload.
References
disease causing renal im pairm ent : a case for t reat m ent. Clin Nephrol. 1989; 31: 119-22.
2. Olin JW, Melia M, Young JR, , Graor RA, Risius B. Prevalence of at herosclerot ic renal art ery st enosis in pat ient s wit h at herosclerosis elsewhere. Am J Med. 1990; 88: 46N-51N.
3. Zierler RE, Bergelin RO, I saacson JA, St randness DE. Nat ural hist ory of at herosclerot ic renal st enosis: a prospect ive st udy wit h duplex ult rasonography. J Vasc Surg. 1994; 19: 250-7.
4. Wright JR, Shurrab AE, Cheung C, et al. A prospect ive st udy of det erm inant s of renal funct ion out com e and m ort alit y in at herosclerot ic renovascular disease. Am J Kidney Dis. 2002; 39: 1153-61.
5. Suresh M, Laboi P, Mam t ora H, Kalra PA. Relat ionship of renal dysfunct ion t o proxim al art ery disease severit y in at herosclerot ic renovascular disease. Nephrol Dial Transplant . 2000; 15: 631-6.
6. Hunt JC, St rong CG. Renovascular hypert ension. Mechanism s, nat ural hist ory and t reat m ent. Am J Cardiol. 1973; 32: 562- 74.
7. Davis BA, Crook JE, Vest al RE, Oat es JA. Prevalence of renovascular hypert ension in pat ient s wit h grade I I I or I V hypert ensive ret inopat hy. N Engl J Med. 1979; 301: 1273- 6.
8. Axelrod DA, Fendrick AM, Carlos RC, et al. Percut aneous st ent ing of incident al unilat eral renal art ery st enosis: decision analysis of cost cost s and benefit s. J Endovasc Ther. 2003; 10: 546- 56.
9. Ayerdi J, Hodgson KJ. Ballon angioplast y and st ent ing for renovascular occlusive disease. Persp Vasc Surg Endovasc Ther. 2004; 16: 25-38.
10. Sahin S, Cim sit C, Andaç N, Balt acioglu F, Tuglular S, Akoglu E. Renal art ery st ent ing in solit ary funct ioning kidneys: t echnical and clinical result s. Eur J Radiol. 2006; 57: 131- 7.
11. Shannon HM, Gillespie I N, Moss JG. Salvage of t he solit ary kidney by insert ion of a renal art ery
st ent. AJR Am J Roent genol. 1998; 171: 217- 22.
12. Cioni R, Vignali C, Pet ruzzi P, et al. Renal st ent ing in pat ient s wit h a solit ary funct ioning kidney. Cardiovasc I nt ervent Radiol. 2001; 24: 372-7.
13. Grunt zig A, Kuhlm ann U, Vet t err W, Lüt olf U, Meier B, Siegent haler W. Treat m ent of renovascular hypert ension wit h percut aneous t ranslum inal dilat at ion of a renal art ery st enosis. Lancet .
1978; 1: 801-2.
14. Scolari F, Ravani P, Pola A, et al. Predict ors of renal and pat ient out com es in at heroem bolic renal disease: a prospect ive st udy. J Am Soc Nephrol. 2003; 14: 1584- 90.
15. Mukherj ee D, Bhat t DL, Robbins M, et al. Renal art ery end- diast olic velocit y and renal art ery resist ance index as predict ors of out com e aft er renal st ent ing. Am J Cardiol. 2001; 88: 1064- 6.
16. Chat ziiannou A, Mourikis D, Agroyannis B, et al. Renal art ery st ent ing for renal insufficiency in solit ary kidney in 26 pat ient s. Eur J Vasc Endovasc Surg. 2002; 23: 49- 54.
17. Sivam urt hy N, Surowiec SM, Culakova E, et al. Divergent out com es aft er percut aneous t herapy for sym pt om at ic renal art ery st enosis. J Vasc Surg. 2004; 39: 565-74.
19. Pillay WR, Kan YM, Crinnion JN, Wolfe JH; Joint Vascular Research Group, UK. Prospective multicentre study of the natural history of atherosclerotic renal artery stenosis in patients with peripheral vascular disease. Br J Surg. 2002;89:737-40.
20. Cherr GS, Hansen KJ, Craven TE, et al. Surgical management of atherosclerotic renovascular disease. J Vasc Surg. 2002;35:236-45.
Correspondence: Ana Terezinha Guillaumon
Rua Hermantino Coelho, 901/11, Bairro Mans„es Santo Antonio CEP 13087-500 – Campinas, SP, Brazil
Tel.: (19) 3296.1986 Fax: (19) 3296.0613 Email: [email protected]
This work was presented at the 36th Brazilian Congress of Angiology and Vascular Surgery and at VII Southern Cone Meeting of Vascular Surgery, held in Porto Alegre, Brazil, on September 4-7, 2005.
No conflits of interest declared concerning the publication of this article.
