Treatment of Renovascular Hypertension with Percutaneous Transluminal Angioplasty: Experience in Spain

Treatment of RenovascularHypertension with PercutaneousTransluminal Angio~lasty:Experience in SpainJose C. Rodriguez-Perez, MDCelia Plaza, MDRicardo Reyes, MDJuan M. Pulido-Duque, MDLeocadia Palop, MDHector Ferral, MDManuel Maynar, MDWilfrido R. Castaneda-Zuniga,

MD

Index terms: Hypertension, renovascu­lar, 81. 72 • Renal arteries, fibrodysplasia,961.7224 • Renal arteries, transluminalangioplasty, 961.1282, 961.72

JVIR 1994; 5:101-109

Abbreviations: FMD = fibromusculardysplasia, PTA = percutaneous translumi­nal angioplasty, SD = standard deviation

PURPOSE: The clinical results of percutaneous transluminal angio­plasty (PTA) were evaluated in patients with renovascular hyperten­sion, and the effect of PTA on blood pressure and renal function was de­termined.PATIENTS AND METHODS: Between February 1982 and December1990,93 hypertensive patients underwent 123 renal artery PTA proce­dures. Mean patient age was 43.4 years (range, 12-78 years). Averagebaseline blood pressure was 162/111 mm Hg (range, 140-230/95-150 mmHg). The cause of renovascular hypertension, as determined with angi­ography, was atherosclerosis in 37 patients, fibromuscular dysplasia in27, and mixed disease in one; 28 patients had renal transplant arterialstenosis.RESULTS: In patients with atherosclerotic renal vascular disease or fi­bromuscular renal artery stenosis, systolic and diastolic blood pressuredecreased significantly (P < .001) at 96 months after PTA. In patientswith renal transplant arterial stenosis, blood pressure also decreasedsignificantly (P < .001) at 12 months after PTA. Technical success wasachieved in 78% of patients with atherosclerosis, 92% ofpatients withfibromuscular dysplasia, and 76% of patients with renal transplants.Complications were seen in 4.8% and were related to renal failure andvessel dissection.CONCLUSION: PTA is the therapy of choice in patients with renovascu­lar hypertension due to fibromuscular dysplasia. Patients with athero­sclerotic renal artery stenosis or stenosis of a renal artery in a trans­planted kidney should be selected according to the anatomy of the lesionand clinical patient characteristics.

I From the Services of Nephrology(J.C.R.P., C.P., L.P., M.M.) and Cardiovas­cular and Interventional Radiology m.R.,J.M.P.D.), Hospital Nuestra Senora delPino, Las Palmas, Canary Islands, Spain,the Department of Radiology, Instituto Na­cional de la Nutricion, Mexico City (H.F.),and the Department of Radiology, Louisi­ana State University Medical Center, 1542Tulane Ave, New Orleans, LA 70112-2822(W.R.C.Z.l. Received October 7,1992; revi·sion requested December 20; revision re­ceived July 20, 1993; accepted July 28. Ad­dress reprint requests to W.R.C.Z.

SCVIR,I994

RENOVASCULAR disease is the under­lying cause of hypertension in ap­proximately 4% of the hypertensivepopulation (1). It is probably themost frequent type of secondary hy­pertension. In patients with severehypertension, the prevalence of reno­vascular disease is approximately30%, reaching almost 45% in patientswith coexisting renal failure.

Loss of renal functional mass hasbeen observed despite adequate medi­cal treatment (2). This observationfavored surgical revascularization asthe primary treatment in patientswith renovascular hypertension (3).However, morbidity and mortalityassociated with this surgical inter­vention are high (4).

After the introduction oftranslu-

minal angioplasty by Dotter and Jud­kins (5) and the successful applica­tion of angioplasty in a renal arterystenosis by Griintzig et al in 1978 (6),this technique has increasingly beenaccepted as an adequate therapeuticoption for patients with hypertensionsecondary to renovascular disease (7).Several authors have reported theirexperience with this technique in pa­tients with atherosclerosis, fibromus­cular dysplasia (FMD), and renaltransplant arterial stenosis with vari­able results (8-23).

The purpose of our study was toevaluate the clinical results ofpercu­taneous transluminal angioplasty(PTA) in patients with renovascularhypertension and the effect of thisprocedure on blood pressure and re-

101

102 • Journal of Vascular and Interventional Radiology

January-February 1994

Table 1Classification of Patients According to Angiographic Data

Lesion LocalizationGroup Disease Unilateral Bilateral

1 Atherosclerotic vascular disease 24 132 FMD 23 43 Renal transplant artery stenosis

Note.-One patient had a mixed (atherosclerotic and FMD) lesion. NA = not available.

Ostial24

214

Non-ostial132511

NA

3

nal function at short- and long-termfollow-up.

PATIENTS AND METHODS

• Patient SelectionOne hundred twenty-three renal

artery angioplasty procedures wereperformed in 93 consecutive hyper­tensive patients (59 male, 34 female)in the period between February 1982and December 1990. The first 22were analyzed retrospectively and theremaining 71 were evaluated pro­spectively. The mean age was 43.4years ± 12.9 (range, 12-78 years).The known duration of hypertensionwas 39.1 months (range, 2-160months). Our institution is a tertiarycare center and serves as a referralcenter for several hospitals in thearea. The reasons for patient referralare as follows: (a) clinical suspicion ofsecondary hypertension, (b) hyper­tension in a patient younger than 30years, (c) damage to target organs ofgrade 11-111 according to classifica­tion of the World Health Organiza­tion (WHO), (d) severe hypertension(diastolic blood pressure> 115 mmHg), (e) hypertension associated withatherosclerosis, or ( f) hypertensionin a patient with a kidney transplantin whom two or more drugs were re­quired for adequate control.

Baseline systolic arterial pressurewas 162.4 mm Hg ± 17 (range, 140­230 mm Hg). Diastolic baseline pres­sure was 111.2 mm Hg ± 9.1 (range,95-150 mm Hg). Thirty-seven pa­tients were receiving antihyperten­sive treatment with two drugs; 53with three drugs; and three with fourdrugs. The most commonly used an-

tihypertensive drugs were beta block­ers, calcium channel blockers, hy­dralazine, prazosin, and diuretics.Twenty-eight patients had renal fail­ure (considered as serum creatininelevel greater than 1.5 mg/dL [132.6fLmol/L]). Every patient underwentintravenous pyelography. No datacould be obtained in two of the pa­tients. Thirteen (14%) had one kid­ney measuring less than 11 cm; 14(15%) had two kidneys measuringless than 11 cm; and 64 (70%) hadnormal kidneys. Digital subtractionangiography and/or conventional an­giography with selective renal arteryinjection was performed in all pa­tients.

On the basis of the angiographicdata, the patients were classified intoone of three groups (Table 1).

• Procedure Protocol andTechnique for PTAPatients with 75% stenosis of the

renal artery were considered candi­dates for transluminal angioplasty.Only three patients were consideredto have less than 75% stenosis of therenal arteries; however, these pa­tients underwent PTA because ofhy­pertension unresponsive to medicaltreatment. Antiplatelet agents weregiven 24 hours before angioplastyand were continued at least 6 monthsafter the procedure (aspirin 250mg/d and dipyridamole 200 mg/d).All antihypertensive agents werestopped on the day of the procedureto avoid the precipitous fall in bloodpressure that occasionally followssuccessful dilation.

Arterial access was obtained bymeans of femoral artery puncture in80% of patients and axillary artery

puncture in 20%. Selective injectionof the renal arteries was always per­formed. Careful technique was em­ployed to traverse the stenotic areaswith metallic soft-tip wires (standard0.035-inch Bentson wire; Cook,Bloomington, Ind) and 0.025-inchsoft-tip wires (Schneider, Minneapo­lis, Minn). Angioplasty catheterswere advanced with careful over-the­wire technique. We used angioplastycatheters with a dilation balloon of adiameter similar to that of a segmentof normal renal artery (approxi­mately 3-8 mm) and inflated it to 5-8atm within the stenosis. In five pa­tients with kidney transplants and intwo patients with atherosclerotic dis­ease, coaxial dilation was performedin small-caliber vessels considered tobe at high risk for complications withballoon PTA. Before balloon dilation,3,000-5,000 U of heparin was di­rectly infused into the renal artery tobe dilated. After dilation, control an­giograms were obtained to evaluatethe morphology of the renal arteries.Contrast material employed was ioxa­glic acid (Hexabrix; Malinckrodt, StLouis, Mo) and, after 1980, iohexol(Omnipaque; Sanofi Winthrop, NewYork, NY) was employed. Mean con­trast material volume per case was 70mL (range, 50-150 mL).

• Evaluation of Technical andClinical ResultsThe results of transluminal angio­

plasty were evaluated according tocriteria previously established in theliterature (20,22) based on the mor­phologic appearance of the dilatedvessels on the postdilation angio­gram. For unilateral stenoses, com­plete success was defined as residual

Rodriguez-Perez et al • 103

Volume 5 Number 1

60 96 months 60 96 months 60 96 months

250.------------------,

200

100 t~-I-I-!-I-!

J.. 1.1. .1.

oL..L.L---'---J'----'--_'-----'-__----.JBefore Id 3 6 12

PTA

Time since angloplasty

250.----------------,

200

Ol-.JW-----.J--'-_--'-__----'--_--'----'Before Id 3 6 12

PTA

Time since angioplasty

250'.-------------------,

200

~ '" ~-I-H100 ~_I-!-I

1 1

OL..L--'---'---'-_.L-_----.J_--'_------'Before 1d 3 6 12

PTA

Time since angioplasty

a. b. c.Figure. Systolic (.) and diastolic (A) blood pressure before PTA and 1 day and 3, 6, 12,60 and 96 months after PTA of renal ar­tery stenosis. The vertical bars indicate one SD above and below the mean. Significances were obtained comparing blood pressuresbefore and after at each time point with use of paired t tests. (a) Atherosclerotic vascular disease, * indicates P < .01, • indicatesP < .05, + indicates P not significant. (b) Fibromuscular renal arterial stenosis. (c) Posttransplant renal artery stenosis. Absenceof symbols in band c indicates P < .001.

stenosis of 50% or less; partial suc­cess, as residual stenosis more than50% but less than or equal to 70%;and failure, as residual stenosis morethan 70% or an inability to cross thelesion with the angioplasty catheter.For bilateral stenoses, complete suc­cess was defined as residual stenosisof 50% or less; partial success, as re­sidual stenosis of 70% or less on atleast one side; and failure, as bilateralresidual stenosis more than 70% orinability to cross the lesions with theangioplasty catheter. Clinical re­sponse was also evaluated (23). Curewas defined as a diastolic pressure of90 mm Hg or less while the patientwas not receiving antihypertensivemedication. Improvement required a15% or greater decrease in the dia­stolic pressure while the patient re­ceived the same or fewer antihyper­tensive drugs as before the proce­dure. AIl other blood pressure re­sponses were considered failures.

• Follow-upOnce the patient was discharged

from the hospital, the primary at­tending physician was in charge ofthe clinical follow-up. The patientswere sent to our department whenreassessment was required.

Periodic measurements of bloodpressure were performed, and serumcreatinine levels were obtained at 24hours, 30 days, and 3, 6, 12, 60, and96 months after dilation by their re­ferring physician or the nephrologystaff. Every year the patients visitedthe nephrology clinic of our hospital.

A second angiogram was obtainedin 23 patients' 3-97 months (50.9months ± 37.2) after the first angio­plasty procedure. The reason for ob­taining the second angiogram waspersisting hypertension and/or wors­ening of renal function. A third an­giogram was obtained in two patientsdue to persisting hypertension.

• Statistical AnalysisData were analyzed with use of the

SPSS/PC plus program and ANOVA­One (IBM). Paired and unpaired ttests were used to compare groups.Data are presented as mean ± Onestandard deviation (SD). Statisticalsignificance was considered whenP < .05.

RESULTS

The effect of PTA On the systolicand diastolic arterial pressure in the

three main groups of patients andthroughout the 96 months of ourstudy is presented in the Figure. Inpatients with atheromatous renalartery stenosis, mean systolic arterialpressure (±1 SD) decreased from168.1 mm Hg ± 18.9 before PTA to156.4 mm Hg ± 17.4 (P < .05) at 12months and to 154.5 mm Hg ± 8.2(P < .01) at 96 months after PTA.Diastolic blood pressure decreasedfrom 112.8 mm Hg ± 10.1 to 92.1mm Hg ± 6.2 (P < .001) at 12months and to 90.5 mm Hg ± 4.1(P < .001) at 96 months after angio­plasty. At 12 months after PTA 3.5%of the patients were cured and 75%were improved; however, at 96months 91% were improved and nonewere cured (Table 2).

In patients with FMD, systolic anddiastolic blood pressure decreasedfrom 154.0 mm Hg ± 8.8 and 111.6mm Hg ± 8.3 before PTA to 141.2mm Hg ± 12.l(P < .000 and 92.1mm Hg ± 6.2 (P < .001) and 138.3mm Hg ± 10.5 (P < .001) and 88.7mm Hg ± 11.3 (P < .000, at 12 and96 months, respectively, after PTA(Figure, part b).

In contrast, among patients withFMD, we found a cure rate of 44%and 50% at 12 and 96 months, re-

104 • Journal of Vascular and Interventional Radiology

January-February 1994

Table 2Cure, Improvement, and Failure Rates after PTA According to Lesion Type

Duration of Follow-up

3 mo 6mo 12mo

Lesion Type N CII/F (%) N CII/F (%) N CII/F (%)

Atherosclerosis 36 2.7/80/17 31 3.2/87/9.6 28 3.5/75/21FMD 26 42/58/0 26 42/58/0 25 44/48/8Transplant kidney 24 4.1/71/25 20 5/80/15 16 6.2/81/12

Note.-C/I/F = cure rate/improvement rate/failure rate, N = number of patients.* Only one patient recorded.

Table 3Atherosclerotic Vascular Disease

N

1621

1

60mo

C/I/F (%)

0/81/1943/48/9.5

100*

N

1112

96mo

CII/F (%)

0/91/9.050/25/25

Characteristic Unilateral

Lesion Localization

Bilateral Ostial Non-ostial

No. of patients 24 13Age (y) 53.0 ± 8.2 53.7 ± 9.1Sex 16 M/8 F 12 M/8 FTime from diagnosis ofHTN (mo) 55.6 ± 30.6 80.8 ± 52.7Familial history of HTN 13 Y/11 N 10 Y/11 NBaseline SP (mm Hg) 163.7 ± 12.0 176.1 ± 26.2SP at 96 mo (mm Hg) 156.6 ± 8.1 152 ± 8.3*Baseline DP (mm Hg) 111.2 ± 6.6 115.7 ± 14.5DP at 96 mo (mm Hg) 90.8 ± 4.9* 90 ± 3.5*Stenosis (%) 82.2 ± 5.3 81.9 ± 5.9

Note.-DP = diastolic pressure, HTN = hypertension, SP = systolic pressure.P values were determined with use of the Student t test.* P < .01 vs baseline.t P < .05 vs baseline.*P < .001 vs baseline.

2452.5 ± 9.619 M/5 F

66 ± 36.316Y/8N

169.1 ± 18.3160 ± 7.0

113.3 ± 8.191 ± 5.4*

81.6 ± 5.8

1354.8 ± 5.79M/4F

61.1 ± 49.57Y/6N

166.1 ± 20.6150 ± 6.3 t

111.9 ± 13.490 ± 3.1*

83.0 ± 4.8

spectively, with a concomitant 48%and 25% of patients improved at 12and 96 months, respectively (Table 2).

Data from patients with renal post­transplant artery stenosis were re­corded until 60 months after angio­plasty, as none of the patients hadreached 96-month follow-up at thetime of this analysis. Statistical sig­nificance (P < .001) was obtained forsystolic and diastolic pressure at 24hours after PTA and was sustainedin the follow-up period for 3, 6, and12 months (Figure, part c). We founda cure rate for these patients of 6.2%and an improvement of 81% at 12months after dilation.

This decrease in blood pressurewas also associated with a decrease inthe number and dose of the antihy­pertensive drugs.

• Group 1: AtheroscleroticVascular DiseaseThis was the largest group ofpa­

tients, and their clinical features arelisted in Table 3. Unilateral lesionswere demonstrated in 65% and bilat­erallesions in 35% of patients.Twenty-four of 37 patients had ostiallesions. The patients with bilateraland ostial lesions had a longer clinicalcourse of diagnosed disease, highersystolic and diastolic blood pressurelevels, and higher serum creatininelevels before angioplasty. A signifi­cant decrease in systolic blood pres­sure was demonstrated 8 years afterangioplasty in patients with bilateraldisease (P < .01) and in patientswith non-ostial lesions (P < .05).There was a significant decrease indiastolic pressure (P < .001) after

PTA in all patients with atheroscle­rotic disease.

Improvement in renal function af­ter PTA was statistically significantonly in patients with bilateral lesions(P < .05). Before angioplasty, a mean(±1 sm of2.6 ± 0.6 antihyperten­sive drugs were used per patient perday. After angioplasty, a mean of1.99 ± 0.6 (P < .05) antihyperten­sive drugs were used per patient perday.

• Group 2: Fibromuscular RenalArtery StenosisThis type of lesion occurred more

frequently in female patients. Non­ostial unilateral lesions were mostcommon (Table 4). Ostial lesionswere found in only two patients, whowere also the older patients in this

Rodriguez-Perez et al • 105

Volume 5 Number 1

Table 4FMD

Lesion Localization

Characteristic Unilateral Bilateral Ostial Non-ostial

No. of patients 23 4Age (y) 35.3 ± 11.2 32.2 ± 10.3Sex 6M/17F 1M/3FTime from diagnosis ofHTN (mo) 34.1 ± 38.8 24.5 ± 16.5Familial history of HTN 11 Y/12 N 2 Y/2 NBaseline SP (mm Hg) 154.7 ± 8.9 150 ± 8.1SP at 96 mo (mm Hg) 138 ± 10.61 140 ± 14.1Baseline DP (mm Hg) 111.7 ± 8.4 111.2 ± 8.5DP at 96 mo (mm Hg) 88.0 ± 11.81 92.5 ± 10.6Stenosis (%) 83.2 ± 4.6* 77.5 ± 5

249.5 ± 6.3*

1 M/1 F36 ± 16.92Y/ON

160

*115 ± 7.0t

87.5 ± 3.5

2533.7 ± 10.5

6 M/19 F32.3 ± 37.511 Y/14 N

153.6 ± 9.0138.3 ± 10.51

111.4 ± 8.488.7 ± 11.31

82 ± 5

Note.-DP = diastolic pressure, HTN = hypertension, SP = systolic pressure.* p < .05 for ostial vs non-ostial lesions.1 P < .001 for 96-month vs baseline data.*One patient was lost to follow-up and the other underwent repeated PTA 2 years after the first procedure for restenosis and de­creased renal function.*P < .05 for unilateral vs bilateral disease.

Table 5Transplant Kidney

No. of patients* 14 11Age (y) 41.7 ± 6.5 32.3 ± 14.11

Sex 11M/3F 9M/2FEvolution ofHTN after transplantation (mo) 7.0 ± 6.0 6.1 ± 3.1Familial history ofHTN 3 Y/11 N 0 Y/11 NBaseline SP (mm Hg) 161.0 ± 13.0 165.4 ± 24.2SP at 60 mo (mm Hg) 135 130Baseline DP (mm Hg) 105.3 ± 5.7 112.2 ± 10.51

DP at 60 mo (mm Hg) 90 95Stenosis (%) 76.7 ± 9.9 76.8 ± 10.0

Note.-DP = diastolic pressure, HTN = hypertension, SP = systolic pressure.* Lesion localization not available for three patients.1 P < .05 vs ostial lesions.

The mean (± 1 SD) number of antihy­pertensive drugs used per patient perday before angioplasty was 2.4 ± 0.5and was 1.83 ± 0.7 3 months afterPTA (P < .005).

• Group 3: Posttransplant RenalArtery StenosisThe patient characteristics in this

group are shown in Table 5. Themean age of patients with ostial le­sions was significantly higher thanthat of patients with non-ostial le­sions. There was a significant de­crease in systolic and diastolic blood

pressure levels 12 months after PTA.However, the small number ofpa­tients with a functional transplant 5years after the procedure made sta­tistical analysis impossible. A signifi­cant decrease (P < .05) in serum cre­atinine level was seen 12 monthsafter PTA in patients with ostial le­sions (Table 6). The number of anti­hypertensive drugs per patient perday was also significantly decreasedafter PTA (P < .05).

• Comparisons between GroupsThe mean age in these three

groups of patients was significantlydifferent. Male predominance wasseen in the group with atherosclero­sis and renal transplants (Table 7).

There was no statistically signifi­cant difference in diastolic pressuresin these groups. By the end of thisstudy, none of the patients whounderwent renal transplantationhad completed 96 months offol­low-up.

Baseline serum creatinine levelwas significantly higher in the pa­tients with atherosclerosis and renaltransplants (P < .05) compared withthat in patients with FMD. Technicalsuccess was achieved in 78% of ath­eromatous lesions, 92% of patientswith FMD, and 76% of patients withrenal transplant. Table 2 shows clini-

Non-ostial

Lesion

OstialCharacteristic

group. One of the patients was lost tofollow-up before 96 months and theother patient underwent repeatedPTA 2 years after the first procedurebecause of an increase in creatininelevels and recurrence of hyperten­sion. Restenosis of the renal arterywas demonstrated angiographicallyin this patient. There was a signifi­cant decrease in systolic and diastolicblood pressure levels after PTA(P < .001) in patients with unilat­eral, non-ostial lesions. The improve­ment in renal function was not sig­nificant 96 months after angioplasty.

106 • Journal of Vascular and Interventional Radiology

January-February 1994

Table 6Evaluation of Renal Function According to Serum Creatinine Level (mg/dL)

Follow-up

Type of Lesion Baseline 3 mo 12 mo 60mo 96mo

Atherosclerosis 2.27 ± 1.65 2.25 ± 2.11 1.8 ± 1.37Unilateral 1.98 ± 1.69 1.89 ± 1.73 1.4 ± 0.85Bilateral 2.79 ± 1.51 2.95 ± 2.66 2.52 ± 1.83Ostial 2.58 ± 1.83 2.72 ± 2.53 2.17 ± 1.73Non-ostial 1.68 ± 1.0 1.41 ± 0.37 1.3 ± 0.27

FMD 1.23 ± 0.57 1.14 ± 0.41 1.14 ± 0.35Unilateral 1.23 ± 0.57 1.13 ± 0.42* 1.14 ± 0.38Bilateral 1.25 ± 0.38 1.2 ± 0.33 1.15 ± 0.19Ostial 2.55 ± 1.76 3.0 2.8Non-ostial 1.13 ± 0.17 1.06 ± 0.16* 1.07 ± 0.10

Renal transplant 2.17 ± 1.35 2.27 ± 2.37 1.69 ± 1.29Ostial 2.2 ± 1.27 2.49 ± 2.99 1.38 ± 0.17*Non-ostial 2.24 ± 1.66 2.18 ± 1.64 2.42 ± 2.28

1.89 ± 1.751.43 ± 0.722.35 ± 2.362.21 ± 2.181.36 ± 0.341.15 ± 0.52t1.16 ± 0.56*1.06 ± 0.20

3.41.04 ± 0.09*

1.3 ± 0.141.41.2

1.61 ± 0.901.73 ± 1.211.48 ± 0.38*1.88 ± 1.31

1.4 ± 0.351.08 ± 0.141.06 ± 0.10

1.2 ± 0.28

1.08 ± 0.14

Note.-To calculate SI unit (f.LmollL) multiply by 88.40. Data are presented as mean ± 1 SD.Significant differences were obtained in each group relative to baseline serum creatinine levels with use of the Student t test.* P < .05.t P < .01.

Table 7Classification of Patients According to Type of Disease

Patient Group

Characteristic AS FMD TXP

Value

<.05*

<.05*t

<.05*H

108.9 ± 8.5

2538.3 ± 11.220 M/5 F6.5 ± 4.63 Y/25 N

162.3 ± 17.6

No. of patients 37 27Age (y) 53.3 ±8.4 34.8 ± 11.0Sex 28 M/9 F 7 M/20 FTime from diagnosis of HTN (mo) 64.3 ± 40.6 32.6 ± 36.2Familial history 23Y/14N 13Y/14NBaseline SP (mm Hg) 168.1 ± 18.9 154.0 ± 8.8SP at 96 mo (mm Hg) 154.5 ± 8.2 138.3 ± 10.5Baseline DP (mm Hg) 112.8 ± 10.1 111.6 ± 8.3DP at 96 mo (mm Hg) 90.4 ± 4.1 88.7 ± 11.3Stenosis (%) 82.3 ± 5.4 82.4 ± 5.0 76.6 ± 9.2 < .05HBaseline serum creatinine (mg/dL)11 2.27 ± 1.6 1.23 ± 0.5 2.1 ± 1.3 < .05*Serum creatinine at 96 mo (mg/dL)'i 1.6 ± 0.9 1.0 ± 0.1 < .01§

Note.-AS = atherosclerosis, DP = diastolic pressure, HTN = hypertension, SP = systolic pressure, TX = kidney transplant.* For AS vs FMD.t For AS vs TX.*For FMD vs TX.§ For AS vs FMD.II To calculate SI unit (f.LmollL) multiply by 88.40.

cal improvement, cure, and failurerates in the follow-up period.

One of our patients had atheroscle­rosis of the right renal artery andFMD of the left renal artery at pre­sentation. The clinical presentation,evaluation, and treatment were notdifferent from those in the othergroups described. Two years after thefirst dilation, the patient was read-

mitted for increasing blood pressurelevels. The angiogram showed bilat­eral restenosis. Bilateral angioplastywas again performed with good results.

• RenalFunctionTable 6 shows the evaluation of

renal function in the patients whounderwent PTA. There was no sig­nificant improvement in renal func-

tion immediately following PTA ex­cept in those patients with FMD.This improvement was more evidentin patients who at presentation hadhigher baseline serum creatinine lev­els and those patients with bilateraldisease, ostial lesions, and atheroscle­rosis. In those patients in whom dila­tion was repeated, there was no im­provement in renal function.

• FailuresTechnical success could not be

achieved in 19 of 93 patients (20%).Dilation was not possible in four pa­tients due to technical difficulties,and residual stenosis greater than75% was present in 15 patients afterthe first PTA. Complete success wasseen in 15 of 24 patients when onerenal artery was dilated, as comparedwith two of 13 patients when bothrenal arteries were dilated. Table 6shows that clinical evaluation wasworse in patients with atherosclero­sis or a renal transplant.

• Patients Who UnderwentRepeated DilationsTwenty-three patients underwent

repeated angiography at 50.9 months± 37 after the first PTA procedure.The underlying indication for re­peated angiography was deterioratingrenal function and increasing bloodpressure levels in 19 of the 23 pa­tients. Six patients had atherosclero­sis, and only three (50%) showedsigns of restenosis on the angiogram.Eleven patients had FMD, and reste­nosis was found in 54%. In the fivepatients with a renal transplant, four(80%) had signs ofrestenosis. Alto­gether, 13 patients developed reste­nosis in the follow-up period. Sixteenrenal PTA procedures were per­formed in these patients. Clinical im­provement was seen in 85%. One pa­tient with FMD and one with a renaltransplant underwent a third PTA,with clinical improvement in bothpatients. Although there was im­provement in blood pressure levels,no change in serum creatinine levelwas observed.

• ComplicationsThere was no mortality in our se­

ries. Our complications included on­set of acute renal failure and techni­cal complications.

Renal failure.-The onset of acuterenal failure was defined by an in­crease of 1 mg/dL (88.4 f.lmoliLl ormore in serum creatinine level per­sisting for more than 48 hours afterthe procedure. In our study group,5% of patients developed acute renal

failure as a complication of PTA; inonly one patient was it related to con­trast medium nephrotoxicity. Renalinfarct was diagnosed in two cases.One of these patients underwent ne­phrectomy. A pathologic specimenrevealed massive renal artery throm­bosis. One patient developed oliguriarequiring long-term hemodialysis.Signs of cortical necrosis were seenon ultrasound scans and renograms.

Technical complications.-Radio­graphic signs consistent with intimaldissection were seen in two patients,one with atherosclerosis and one witha renal transplant. The patient with arenal transplant also developed acuterenal failure and underwent surgicalrevascularization with good subse­quent recovery. Spontaneous im­provement was seen in the dissectionin the patient with atherosclerosis.Improvement in renal function wasalso seen.

DISCUSSION

PTA has been accepted as one ofthe therapeutic options for renovas­cular hypertension (6). In some casesPTA is the therapy of choice in thetreatment of significant renal arterystenosis. Several reports describe theeffects of PTA on renovascular hyper­tension; however, to our understand­ing, there are no strict criteria tomeasure the clinical response and theeffects on atherosclerosis. The term"cure rate" has been adequately es­tablished; however, other terms suchas "clinical improvement" are some­what subjective, as has been dis­cussed by Brawn and Ramsay (17).

The inconsistent results of PTA inthe treatment of atherosclerotic renalartery stenosis in the reviewed stud­ies suggest that surgical revascular­ization and aggressive medical treat­ment may be two important optionsto consider in this particular patientpopulation. Our study group includedconsecutive patients with historysuggesting the possibility of renovas­cular hypertension. Intravenous py­elography was not useful in ourcases, as has been previously de-

Rodriguez-Perez et al • 107

Volume 5 Number 1

scribed (24,25). The captopril test,which is sensitive and specific(26,27), followed by digital subtrac­tion angiography should be per­formed in the evaluation of these pa­tients.

Bell and coworkers have describedthat the lateralized renin index fromrenal veins is a good predictor of re­novascular hypertension and an aidto selection of patients for PTA in therenal arteries. In our study the num­ber of Vaughan indexes obtainedwere too small and did not allow foradequate statistical evaluation. Wewere able to achieve good technicaland clinical results in most of ourcases, and our data confirm or sup­port previously released data (8,11,12,20,28-30) if we consider the curerate and clinical improvement ratetogether.

We found that bilateral atheroscle­rotic renal artery stenosis is not apoor prognostic factor, as has beenpreviously reported by Bell and co­workers (12); however, patients withostial lesions had significantly worseresults and more failures than pa­tients without ostial involvement(70% vs 100%), the former with a30% failure rate. Sos and coworkers(20) and Canzanello et al (11) did notfind significant differences in thesetwo groups of patients, although onlyunilateral lesions were considered.Even though the immediate resultafter PTA apparently was not influ­enced by the ostial involvement, ourresults show that in none of the pa­tients with ostial lesions was a cureachieved. Improvement in the controlof hypertension 96 months after PTAwas seen in 80% of the patients.

We conclude that the presence ofan ostial lesion in atherosclerotic re­nal artery stenosis is not an absolutecontraindication to performing PTA,although PTA in these patients isassociated with a higher prevalenceoffailure and a less favorable outcome.

The progressive nature of athero­sclerotic disease is illustrated in thepatients who underwent repeatedangiography. In three patients, reste­nosis was seen and in another threepatients, new lesions had developed.

108 • Journal of Vascular and Interventional Radiology

January-February 1994

PTA success was higher for FMDthan for atherosclerosis, with a curerate of 43% and 50% at 60 and 96months, respectively, versus no curewith atherosclerosis. Our technicalresults in the treatment of FMD arebetter than those described by otherauthors (20). Also, expert contempo­rary surgical revascularization offersgood results in the treatment of FMD(3). This difference in response totherapy between FMD and athero­sclerotic disease could be explainedby the higher incidence of essentialhypertension in patients with athero­sclerosis, making the arterial stenosisa secondary lesion (27).

Transplant renal artery stenosiswarrants separate consideration(31,32). Stenotic areas, usually seenclose to the anastomotic site, are seenin approximately 25% of renal trans­plantations (33). Severe hypertensionor abnormal renal function, however,is seen in only 3%-7% of these pa­tients (34-36). In these cases, resultsof renin hypersecretion or captopriltests are not useful in the evaluationof a patient. Surgical treatment hasbeen associated with 50% ofloss oftransplanted kidneys and 13% of re­interventions and with a 5% mortal­ity rate (36). These facts have favoredthe use of PTA in this particular pa­tient group. The best results for PTAin a transplanted kidney have beenobtained with lesions distal to theanastomotic site (36). This was notthe case in our study group, in whicha large proportion of patients hadlesions at the anastomotic site, prob­ably due to surgical technique. Suchanatomy can render PTA extremelydifficult to perform (36). Althoughour clinical improvement rate wasacceptable, the cure rate was only4%-7%, possibly due to the multiplefactors in the renal transplant pa­tient that could lead to systemic hy­pertension (steroids or cyclosporineadministration or rejection) or due tothe location of stenosis (19).

We found no difference in treat­ment results in the post-PTA period(60 months) in patients with anasto­motic lesions or more peripheral le­sions. We do not have enough data to

establish if either type responds bet­ter to PTA. The restenosis rate inthis group of patients is high (80%).

Some authors have described animprovement in renal function afterPTA (20), but this has not been con­firmed by others (37). Thirty percentof our patients had renal failure priorto PTA and, although there was anonsignificant improvement in se­rum creatinine levels, there was atrend to stabilization of renal func­tion after PTA. This stable renalfunction status was more evident af­ter the 3rd month following PTA.Those patients with severe renal fail­ure at the time of PTA slowly devel­oped chronic renal failure in spite ofadequate control of systemic bloodpressure. Clinical improvement wasseen in 85% of the patients who un­derwent a second PTA. Adequateblood pressure control with a de­crease in medication dose wasachieved. A change in serum creati­nine levels was not observed in anypatient. This suggests that patientswho underwent a first PTA proce­dure successfully may undergo a sec­ond PTA with adequate results. Al­though mortality rates after PTAhave been as high as 3% (38), therewere no immediate deaths in ourstudy group. Our complication rate of8.6% is similar to that reported byother authors (20,38). We had me­chanical complications in 2% ofpa­tients, and only one patient requiredsurgery. Our most frequent complica­tion was acute renal failure (5%);however, only one patient requiredhemodialysis.

CONCLUSION

Although the cure rates after PTAin our study group are not outstand­ing, the improvement and cure ratestogether are similar to those previ­0usly published.

Longer term results to 5 years havethe disadvantage of significant pa­tient loss to follow-up. This limitscritical evaluation of the procedureand its long-term results. Better re­sults are obtained in patients with

non-ostial lesions and with FMD.PTA for atherosclerotic vascular dis­ease rarely cures arterial hyperten­sion, but improved blood pressurecontrol is often achieved, albeit at theexpense of troublesome complica­tions. Our results suggest that angio­plasty should still be considered as anadequate therapeutic option and, insome cases, as a primary therapy dueto its adequate results, low morbidityand mortality, possibility of repeatingangiography and dilations, and thelower costs of the procedure. How­ever, we suggest that documentationof recurrent renal artery stenosis isan indication for other treatments,such as surgical revascularization.Delineation of the role of newer tech­niques such as renal artery stentplacement in the management of re­novascular hypertension can beachieved only through appropriaterandomized trials.

Acknowledgments: This project wasthe result of the effort of several col­leagues who were involved in the data rec­ollection and patient recruitment thatmade collaboration in this manuscriptpossible. We would like to express ourdeepest gratitude to Drs Agustin Toledoand Dolores Checa of the Hospitallnsu­lar, Las Palmas; Drs Maria Luisa Mendezand Javier Garcia of the Hospital NuestraSenora de la Candelaria, Tenerife; ourcolleagues from Hospital Carlos Haya,Malaga, and Hospital Clinic Provincial,Barcelona. Special thanks also to the staffof the Nephrology Service and VascularRadiology of Hospital Ntra Sra del Pino,who helped in the evaluation and analysisof the radiologic studies. Finally, wethank Joan Watkins for her excellent sec­retarial support.

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