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CLINICAL STUDY

Long-Term Results of Stent-Graft Placement toTreat Central Venous Stenosis and Occlusion in

Hemodialysis Patients With Arteriovenous FistulasRobert G. Jones, MBChB, MRCP, FRCR,

Andrew P. Willis, MBBS, MRCS, FRCR,Catherine Jones, MBBS, BSc, FRCR,

Ian J. McCafferty, MBBS, MRCP, FRCR, andPeter L. Riley, MBChB, MRCP, FRCR

ABSTRACT

Purpose: To determine the effectiveness of stent-grafts for the treatment of central venous disease in hemodialysis patients withfunctioning arteriovenous (AV) fistulas.

Materials and Methods: Between October 2004 and March 2010, 42 VIABAHN stent-grafts were deployed in central veins of

30 patients (16 men, 14 women; mean age 60 y) with functioning AV fistulas and central venous disease that did not respond to

percutaneous transluminal angioplasty (PTA). Eighteen patients had central vein stenosis and 12 had occlusion. Previous PTA and/or

bare metal stent placement had been performed in 23 patients (77%). Surveillance was carried out at 3, 6, 9, 12, 18, and 24 months

with diagnostic fistulography. The mean follow-up was 705 days (range, 661,645 d). Statistical analysis included KaplanMeier and

log-rank studies.

Results: Technical success rate was 100%. Primary patency rates were 97%, 81%, 67%, and 45% at 3, 6, 12, and 24 months,

respectively. Primary assisted patency rates were 100%, 100%, 80%, and 75% at 3, 6, 12, and 24 months, respectively. Patients

without previous procedures had significantly shorter times to repeat intervention (P .018) than those who had undergone PTA or

bare metal stent placement previously. Patients with occlusive lesions had a significantly shorter primary patency interval (P .05)than patients with stenoses. Occluded veins were more likely to require further stent-grafts (P .02). Twelve patients required further

stent-grafts to maintain patency. There was one minor complication.

Conclusions: Stent-graft placement to treat central venous disease in hemodialysis patients with autogenous AV fistulas is safe andeffective if PTA fails to maintain luminal patency.

ABBREVIATIONS

AV arteriovenous, PTA percutaneous transluminal angioplasty

Central venous disease is a commonly encountered problem

in the hemodialysis population and results in significant

morbidity. It is often clinically apparent in those with

functioning hemodialysis access, either as an autogenous

arteriovenous (AV) fistula or an AV graft. Incidences are

typically quoted between 1.5% and 17% but have been as

high as 40% (13). AV fistula or graft thrombosis can occur

secondary to central venous disease, resulting in loss of

dialysis access altogether or necessitate surgical ligation for

symptomatic control.

Central venous disease is thought to result from local

trauma invariably as a consequence of repeated percutane-

ous hemodialysis catheter placement and altered flow dy-

namics (4,5). Endovascular management is well established

From the Radiology Department, Queen Elizabeth Hospital Birmingham, Uni-

versity Hospital Birmingham NHS Trust, Edgbaston, Birmingham B15 2TH,

United Kingdom. Received September 21, 2010; final revision received May

29, 2011; accepted June 7, 2011. Address correspondence to R.G.J.;

E-mail: [email protected]

None of the authors have identified a conflict of interest.

From the SIR 2007 Annual Meeting.

SIR, 2011

J Vasc Interv Radiol 2011; xx:xxx

DOI: 10.1016/j.jvir.2011.06.002
mailto:[email protected]:[email protected]


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and accepted in this setting, and includes percutaneous

transluminal angioplasty (PTA) and/or bare metal stent

placement, with no clear advantage of one modality versus

the other (611). Significant recurrent stenosis rates are

reported, and the condition is thought to result from neo-

intimal hyperplasia.

The use of stent-grafts in AV fistula salvage has been

described in several small series with encouraging results

(1215). More recently, stent-graft placement has been

described as the gold standard for the treatment of AV graft

venous anastomosis stenosis (16). With these observations

in mind, it seems feasible that the use of stent-grafts is

applicable to the central venous scenario. The objective of

the present study was to evaluate patency and performance

of stent-grafts as an alternative to bare metal stents in

central venous disease that does not respond to PTA in

patients with upper-limb AV fistulas.

MATERIALS AND METHODS

Study DesignThis study is a retrospective analysis of data collected

between October 2004 and March 2010 pertaining to the

use of VIABAHN (W.L Gore and Associates, Flagstaff,

Arizona) stent-grafts as an alternative to bare metal

stents to treat central venous disease that did not respond

to PTA in patients with ipsilateral upper-limb AV fistulas

who were undergoing hemodialysis at a single institu-

tion. Included were those with recurrent stenosis previ-

ously treated successfully with PTA, in-stent stenosis in

previously placed bare metal stents, and/or recurrentstenosis in association with stent-grafts (including 0.5

cm to either side of the device, ie, edge stenosis)

placed during the review period. Patients were identified

via our venographic surveillance program or if symptoms

of upper-limb venous hypertension developed or dialysis

venous pressures were increased. A normal coagulation

profile was required at the time of the procedure, and any

form of access infection or concurrent systemic infection

(including bacteremia) was considered a contraindication

to stent-graft insertion.

Surveillance was carried out at 3, 6, 9, 12, 18, and 24

months with diagnostic fistulography, and information re-garding resolution of symptoms was also collected at these

intervals. The study was compliant with institutional guide-

lines pertaining to the retrospective collection and analysis

of data.

Procedural TechniqueInitial central venous assessment was carried out with

digital subtraction venography via direct puncture of the

venous arm of the upper-limb AV fistula. The femoral

route was chosen primarily for subsequent intervention.

A multipurpose catheter and hydrophilic guide wire com-

bination was used to probe occluded veins, and, whenthey had been crossed, a 4-F catheter was advanced

beyond the lesion and the wire was exchanged for a long

stiff guide wire (Amplatz Super-stiff wire; Boston Sci-

entific, Natick, Massachusetts). The vascular access

sheath was then exchanged according to PTA balloon

and subsequent stent-graft compatibility. If direct AV

fistula access was required, consideration was given to

the application of a purse-string suture to prevent pro-

longed bleeding on removal of the access sheath.

Periprocedural antibiotic prophylaxis was not used.

In all cases, 2,000 U of heparin was administered intra-

venously before the intervention. PTA was carried out

with a high-pressure balloon in all cases (Conquest or

Atlas balloon; Bard, Covington, Georgia), and a stent-

graft was subsequently placed if residual stenosis of 50%

or more was observed. Venous pressure gradients were

measured in cases of borderline residual stenosis at the

discretion of the individual interventional radiologist. A

gradient across the lesion or more than 10% systolic

pressure was considered significant, and in this situation,

a stent-graft was placed. The threshold used in the pres-ent study has been reported to define significant central

venous stenosis (17).

A 10% oversizing versus the normal adjacent venous

diameter measured on venography was used when sizing

balloons and stent-grafts, and an equivalent diameter was

used for deployment in an existing bare metal stent.

Stent-grafts were not considered if deployment would

involve covering patent ipsilateral internal jugular and

contralateral brachiocephalic veins. Patients did not rou-

tinely undergo anticoagulation, and no additional spe-

cific medical therapy was instigated after stent-graft

placement.

DefinitionsTechnical success of stent-graft placement was defined

as exclusion of a stenosis or occlusion without significant

residual stenosis ( 30%). Clinical success was defined

as resolution of signs and symptoms related to upper-

limb venous hypertension. Technical failure of PTA was

defined by the presence of residual stenosis of at least

50%.

Primary patency was defined as stent-graft patency

without the need for repeat intervention (balloon dilation or

further stent-graft placement) within the existing stent-

graft, including 0.5 cm to either side (ie, edge segment).

The time point marking the end of primary patency was the

date of the first repeat intervention. Primary assisted pa-

tency was defined as stent-graft patency irrespective of the

need for, or number of, further interventions within the

stent-graft or edge segment. Secondary patency was defined

as occlusion of the central vein.

Statistical AnalysisStatistical analysis was performed by using SPSS statistical

software (version 17; SPSS, Chicago, Illinois). Means andSDs were calculated for continuous variables. Survival

2 Stent-Grafts in Hemodialysis Recipients With AV Fistulas Jones et al JVIR


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curve analysis with KaplanMeier methodology was usedto demonstrate event-free outcomes of primary and primary

assisted patency. Log-rank statistics were used to compare

event-free outcomes between subgroups of patients. Fol-

low-up data were censored from KaplanMeier analysis if

the patient was lost to follow-up for logistical reasons or

died from unrelated causes, if no event had occurred at

the time of data retrieval, or if renal transplantation

occurred for reasons unrelated to stent failure. A P value

of .05 or lower was considered to represent statistical

significance.

RESULTS

In the period between October 2004 and March 2010, 16

men and 14 women (mean age, 60 y; range, 27 88 y)

underwent stent-graft placement (Table 1). The mean fol-

low-up period was 705 days (range, 661,645 d). One

patient was lost to follow-up.

Technical and Clinical OutcomesThe technical success rate was 100%. The mean time for

each case was 102 minutes (range, 45 min to 2 h).

Initially, 30 stent-grafts were placed in 30 patients.Twenty-one patients had previous PTA, 12 had bare

metal stents (with true in-stent stenosis), and seven had

received a stent-graft at first intervention after unsuc-

cessful PTA. Eighteen of the 30 patients required further

intervention to maintain patency during the study period.

Twelve of these patients required further stent-graft

placement (at a mean of 1,016 d) to maintain patency

after failed repeat PTA, 10 had edge stenosis, and two

had true intrastent-graft stenosis.

Stent-graft deployment in all cases (initial and repeat)

was achieved via the right common femoral vein in 31

patient episodes, the left common femoral vein in one, the

AV fistula in three, and via through-and-through access in

seven patients with occlusive venous disease. To avoid

prolonged bleeding and potential thrombotic complications

that could be associated with the larger vascular sheaths

required, the femoral approach for stent-graft deployment

was favored versus direct AV fistula access.

The following sizes of VIABAHN stent-grafts were

used: 13 mm 5 cm (n 17), 11 mm 5 cm (n 17),

10 mm 5 cm (n 6), 10 mm 10 cm (n 1), and 9

mm 10 cm (n 1; Table 2).

Thirty-eight stent-grafts (90%) were postdilated per

manufacturers instructions for use. No migration was

observed in those that were not dilated, and postdeploy-

ment venography did not suggest luminal irregularity,

although we recognize this can be overlooked on venog-

raphy. No stent-graft fractures were observed in the

study period.

All patients who initially presented with arm swelling

reported complete resolution within 7 days of stent-graft

placement, and this was recorded at the first surveillance

fistulography visit on direct questioning. There was a single

complication in one patient in whom a stent-graft was

deployed across a venous collateral vessel supporting head

and neck drainage, but there were no significant clinical

sequelae. No stent-graftrelated infections were encoun-

tered. There were 10 deaths (33%) during the study period,

but none were procedure-related or occurred within 30 days

of stent-graft placement.

Patency

Primary patency rates for all initial stent-grafts (excludingthose that required a further stent-graft) were 97%, 81%,

Table 1. Demographic Data on Patients, Venous Lesions,

and Previous Interventions

Characteristic Value

Age (y)

Mean 60

Range 2788

Sex

Male 16

Female 14

Central venous lesion

Occlusion 12 (40)

Stenosis 18 (60)

Site of venous lesion

Left brachiocephalic 24 (75)

Left subclavian 3 (9)

Right brachiocephalic 4 (12)

Right subclavian 1 (4)

Site of stent-graft

Left brachiocephalic 31 (74)

Left subclavian 3 (7)

Right brachiocephalic 7 (17)

Right subclavian 1 (2)

Previous intervention

None 7

PTA 21

Bare metal stent 12

Note.Values in parentheses are percentages. PTA per-

cutaneous transluminal angioplasty.

Table 2. Number of Stent-Grafts and Dimensions

According to Target Vein

Site

Stent-Graft Dimensions (mm cm)

13 5 11 5 10 10 10 5 9 10

Left BCV 12 12 6 1

Right BCV 4 2 1 Left SCV 3

Right SCV 1

Note.BCV brachiocephalic vein; SCV subclavian vein.

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67%, and 45% at 3, 6, 12, and 24 months ( Fig 1). Primary

assisted patency rates were 100%, 100%, 80%, and 75% at3, 6, 12, and 24 months, respectively. Patency rates and

event-free survival analysis is shown in Table 3. Log-rank

analysis showed that patients undergoing stent-graft place-

ment without previous procedures (n 7) had significantly

shorter time to repeat intervention (P .018) than those

who had undergone previous PTA or bare metal stent

insertion (n 23; Fig 2). Patients with occlusive lesions

(n 12) also had a significantly shorter primary patency

interval (P .05) than patients with stenoses (n 18;

Fig 3) and were more likely (P .02) to require a further

stent-graft to maintain primary assisted patency. Primary

assisted patency could not be maintained in only one pa-tient, in whom patency was lost at 259 days after the initial

stent-graft procedure. A survival curve was not created for

that reason.

DISCUSSION

PTA and bare metal stent placement are recognized and

established methods of treatment of hemodialysis-associ-

ated central venous disease. PTA alone has been reported to

be associated with primary patency rates at 3, 6, and 12

months as high as 58%, 23%63%, and 12%53%, respec-

tively (7,18,19). Central venous lesions that exhibit elastic

recoil after PTA may show early failure and often require

stent placement to maintain luminal patency, as this pro-vides additional structural support. Stent placement is rec-

Figure 1. Primary patency after stent-graft placement for the

30 original stent-graft placements, not including those that re-

quired a further stent-graft to maintain patency. (Available in

color online at www.jvir.org.)

Table 3. Primary and Assisted Primary Patency After Stent

Placement

Follow-up

(mo)

No. of

Pts

Primary

Patency (%)

Primary Assisted

Patency (%)

3 29 97 (3.3) 100 (NA)6 25 81 (7.6) 100 (NA)

9 20 77 (8.3) 95 (4.4)

12 19 67 (9.7) 94 (NA)

18 13 51 (11) 92 (NA)

24 12 45 (11) 91 (NA)

Note.Values in parentheses represent SE. NA not appli-

cable (because only one patient did not have primary as-

sisted patency at 9-month follow-up).

Figure 2. KaplanMeier primary patency after stent-graft

placement in central venous disease in patients with and with-

out previous central venous intervention.

Figure 3. KaplanMeier primary patency after stent-graft

placement for occlusive and stenotic lesions.

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ommended in this scenario or when there is a recurrence ofstenosis within 3 months (20,21). As with PTA, similar

trends of disease recurrence with bare metal stents are

reported, with patency rates at 3, 6, and 12 months ranging

from 63% to 100%, 42% to 89%, and 14% to 73%, respec-

tively (19).

The application of stent-grafts in hemodialysis au-

togenous AV fistula circuits has been reported in several

series with encouraging results (1215,22), but these

studies mainly address their function in the peripheral

arm of the AV fistula and in the setting of fistula salvage

following PTA-associated rupture or pseudoaneurysm

formation. Application of stent-grafts in the central veinshas been reported by Quinn et al (23), who used preex-

panded polytetrafluoroethylene sewn onto Palmaz stents

(Johnson and Johnson, Warren, New Jersey). In this

study (23), only six central venous stenoses were treated,

with 2-, 6-, and 12-month primary patency rates of 40%,

32%, and 32%, respectively. In addition to the mechan-

ical support offered by the metallic stent component of

the stent-graft, the polytetrafluoroethylene lining may

provide a more compatible and less turbulent luminal

environment for endothelialization than a bare metal

stent. In animal models, it is suggested that stent-grafts

maintain longer patency rates than bare metal stents ( 24).Most historical studies looking at PTA and bare

metal stent outcomes (7,10) lack the interval 3-month

venographic follow-up carried out in the present series.

Although a more critical analysis would be required to

make an accurate comparison, our stent-graft patency

rates compare favorably with these outcomes, and, in

particular, our primary assisted patency rates exceed

previously reported results (911). As with PTA and

bare metal stents, we observed recurrent stenosis in our

stent-graft series, and this typically occurred within 0.5

cm of the edge of the stent-graft (Fig 4). In two cases of

recurrent stenosis, further stent-graft placement was re-quired for true intrastent-graft stenosis that did not

respond to repeat PTA. Similar observations of edgestenosis have been reported previously (25), which may

have resulted from turbulent flow in this region. The

central portion of the stent-graft is less likely to show

intimal hyperplasia and may be a more favorable envi-

ronment for endothelialization.

In our sizing protocol, the diameter of the normal

adjacent vein as measured on digital subtraction venog-

raphy was used as a reference, with a 10% oversizing of

the stent-graft diameter. In cases of in-stent stenosis, we

used a stent-graft of the same diameter as the preexisting

stent. A larger-diameter device would be constrained by

the bare metal stent, whereas an equivalent diameter isfurther supported by an outer circumference of intimal

hyperplasia. Length measurement included an additional

0.5 cm to either side of the lesion. Deployment across

contralateral brachiocephalic or ipsilateral jugular veins

was avoided except when these were already occluded as

demonstrated by sonographic and venographic studies

(Fig 5). Dominant venous collateral vessels were also

considered in this fashion, and one complication was

encountered in the present series in which a stent-graft

compromised collateral drainage of the head and neck,

which resulted in head swelling. Other smaller collateral

vessels were present and developed further within 24hours, and the swelling resolved spontaneously, obviat-

ing further intervention.

The limitations of the present study include the cohort

size and the lack of correlation with measurable dialysis

function; however, all patients reported clinical improve-

ment after stent-graft placement. Another limitation is the

lack of comorbidity data, as this can be associated with

increased risk of recurrent stenosis after central venous

interventions (7,10).

In conclusion, this retrospective review suggests that

the application of stent-grafts to treat central venous disease

unresponsive to PTA in hemodialysis patients with func-tioning AV fistulas is safe and effective. However, larger

Figure 4. (a) Diagnostic central venogram in a patient with an existing stent-graft in the left brachiocephalic vein that had been placed

6 months earlier. Note the edge stenosis (arrow), which required a second stent-graft to maintain patency (b).

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prospective studies are required to accurately determine

their exact role.

ACKNOWLEDGEMENT

The authors acknowledge Dr. M. Dhillon for his input

during the early phase of this work.

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Figure 5. Central venography in a patient with a functioning right brachiocephalic AV fistula and a swollen right arm. (a) Diagnostic

venography demonstrates in-stent stenosis within a right brachiocephalic vein bare metal stent, which had been placed 8 months

earlier. (b) No improvement was noted after PTA, and therefore a stent-graft was placed within the existing bare metal stent. A

satisfactory result was obtained, followed by resolution of arm swelling within 7 days.


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