Case Report

DepartmenWatford, Hertf

CorrespondHospital, VicaKingdom; E-m

Ann Vasc Surghttp://dx.doi.or� 2014 Elsevi

Manuscript rec

2014; publishe

Successful Thrombolysis of a Late AcuteThrombotic Occlusion of an Aortic Prosthesisafter Endovascular Aneurysm Repair

James Waiting, Abigail Dias, Tulsi Patel, Tim Pencavel, Kevin Rosenfeld, and Sanjeev Sarin,

Watford, United Kingdom

A 79-year-old man with a previous endovascular aneurysm repair (EVAR) for a 5.4-cm abdom-inal aortic aneurysm presented 3 years after the procedure with sudden onset lower limb paral-ysis and pain. The diagnosis of acute aortic thrombosis within the aortic prosthesis graft wasmade and confirmed on computed tomography. Thrombolysis delivered into the graft via a radio-logically placed catheter successfully dissolved the thrombus and resulted in improvement of thepatient’s symptoms. We discuss the presentation of, and role in management of thrombolysis in,this rare complication of aneurysm repair.

Endovascular repair of aortic aneurysms is a well-

recognized and commonly used surgical technique,

with the incidence of endovascular aneurysm repair

(EVAR) techniques increasing in recent years as

both technique and technology evolve. We present

a case of complete occlusion of an EVAR graft and

its treatment and resolution with thrombolysis.

As far as we are aware, this is the only reported

case of successful thrombolysis to an acutely throm-

bosed aortic segment of an EVAR graft.

CASE REPORT

A 79-year-old man presented with a 1-day history of sud-

den onset of bilateral lower limb paralysis and pain, with

absent pulses femoral pulses. Three years previously, he

had undergone an EVAR for a 5.4-cm aneurysm. An oc-

clusion of the right limb of the EVAR was diagnosed 9

t of Vascular Surgery, Watford General Hospital,ordshire, UK.

ence to: James Waiting, MBBS, iBSc, Watford Generalrage Road, Watford, Hertfordshire, WD18 0HB, Unitedail: jameswaiting@doctors.org.uk

2014; -: 1–4g/10.1016/j.avsg.2014.02.027er Inc. All rights reserved.

eived: April 28, 2013; manuscript accepted: February 24,

d online: ---.

months after the EVAR and resultant limb ischemia

treated by a femorofemoral crossover graft with an 8-

mm diameter Dacron graft.

He was initially investigated by way of computed to-

mography (CT) angiography of the abdominal aorta

and arterial duplex scanning, which excluded spinal pa-

thology as a cause of his symptoms and revealed an

occluded EVAR graft at a level just below the renal ar-

teries (Fig. 1).

In view of the acute nature of the presentation and

limited alternative surgical reconstructive options, we

elected to attempt intraarterial thrombolysis. Under radio-

logic guidance, a catheter was inserted into the proximal

end of the occluded graft via a percutaneous left femoral

approach. Angiography confirmed complete graft occlu-

sion (Fig. 2). The patient was transferred to the high de-

pendency unit for monitoring and thrombolysis with

recombinant tissue plasminogen activating factor (r-

TPA) delivered through the catheter at a dose of 1 mg/hr

for 20 hr, before a repeat catheter angiography to check

success. After 16 hr thrombolysis, the feet were warmer

and pedal pulses easily palpable on the left with no evi-

dence of ‘‘trash’’ embolization. An angiogram performed

20 hr after thrombolysis was initiated confirmed the clin-

ical findings, in that the EVAR graft, left lower and left

external iliac arteries were patent. There was persistent

thrombus in the right side of the femorofemoral bypass

graft. The catheter was withdrawn into the left iliac artery

and the dose of r-TPA reduced to 0.5 mg/hr for a further

24 hr. A check angiogram following this revealed

1

Fig. 1. Coronal section of CT angiogram, showing

thrombus within the stent graft, starting just distal to

the renal arteries.

Fig. 2. Angiogram showing thrombosis of aortic pros-

thesis graft. (Catheter used to deliver local thrombolysis).

2 Case Report Annals of Vascular Surgery

complete lysis of the acute thrombus. The chronically

occluded right limb of the EVAR graft remained occluded.

The angiogram suggested fibrointimal hyperplasia of the

femorofemoral graft, which may have been the precipi-

tating factor in the acute occlusion (Fig. 3A). There was

no iliac stenosis within either the native vessel or EVAR

graft to account for the occlusion.

After thrombolysis, the patient’s paralysis and pain

resolved. He was treated with low-molecular-weight hep-

arin and commenced on life-long oral anticoagulation

withwarfarin, with a target international normalized ratio

(INR) of 2.5e3.5. The patient was treated on the high de-

pendency unit for 8 days and then stepped down to a sur-

gical ward from where he was discharged 4 days later

when his INR was within the target range. At routine

follow-up, the patient has made an excellent recovery

with no signs of recurrent occlusion (Fig. 3B). Elective

angioplasty to the crossover graft, with bridging heparin

therapy, has been considered but may be unnecessary as

he has had no further symptoms on oral anticoagulation.

Currently, at 1 year since the acute event, there is no sign

of reocclusion either clinically or on CT scanning.We plan

for the patient to undergo ultrasound surveillance once in

3 months, with Doppler flow analysis, for the next year

and once in 6 months for a further 3 years, at which stage

if he remains asymptomatic, he will be considered for

discharge.

DISCUSSION

EVAR is a commonly used surgical intervention for

aneurysm repair. It has advantages over open

repair of aneurysms as it is minimally invasive

and leads to shorter hospital stays, decreased blood

loss, and decreased early mortality rates.1,2 Howev-

er, EVAR is associated with a greater complication

and reintervention rate, which necessitates long-

term monitoring of the patient.3 Complications

include graft migration, endoleak, limb occlusion,

limb kinking, and continued expansion of the

aneurysm.4,5

Limb occlusion is a common complication of

EVAR. It is highly dependent on the type of graft

used, occurring in up to 40%of unsupported grafts.4

Modern grafts, however, would be expected to have

limb occlusion rates of around 5e10%.6e8 Various

risk factors have been postulated, including deploy-

ment within the external iliac artery (rather than

common iliac), younger age patients, and kinking

of grafts.6,9 In the postoperative period, the presence

of raised peak systolic velocities on Doppler ultra-

sound is also predictive of occlusion.10,11 Intraoper-

ative intravascular ultrasound has been shown to be

a feasiblemethod of assessing EVAR, but as yet there

Fig. 3. (A) Catheter angiography showing resolution of

thrombus at 48 hours with fibrointimal hyperplasia in

femorofemoral crossover graft, which may have been

the precipitating factor for graft thrombosis. (B) Coronal

section of CT angiogram at 3 months showing persistent

flow through aorta and femorofemoral crossover graft.

Vol. -, No. -, - 2014 Case Report 3

is limited evidence on its use in preventing limb

occlusion.12

Occluded limbs of EVAR grafts may be treated

surgically with a femorofemoral crossover graft to

treat the occlusion and restore flow or through an

endovascular approach such as balloon catheteriza-

tion, thrombolysis, and/or stent placement.13e15

Success rates for thrombolysis in the literature are

in the region of 50%, although in the setting of

acute limb ischemia, it has been noted that patients

treated initially with thrombolysis require less

traumatic secondary intervention.16e18 The distal

embolus rate after thrombolysis for acute ischemia

is reported as being in the region of 10%, with an

increase in stroke and hemorrhage risk. More

recently, a technique has been described using

catheter thrombectomy in conjunction with a voll-

mar ring stripper.19 However, experience with all

these techniques is sufficiently limited as to make

generalizable conclusions impossible. Reconstruc-

tive options include extra-anatomical bypass or

aortofemoral bypass grafting; in the current case,

we felt that the acute presentation, coupled with

the patient’s comorbid state, made at least a trial

of thrombolysis an attractive therapeutic option.

Informed written consent, including a discussion

of risks, was obtained before commencement of

therapy, and the patient was keen to avoid further

invasive surgery. However, thrombolysis may not

be appropriate in cases where the thrombosis is

detected later, when the thrombus has organized

and would not be amenable to thrombolysis, or if

there was acute limb-threatening ischemia, in

which situation rapid restoration of circulation by

definitive surgical means would reduce the risk of

limb loss.

The occurrence of complete occlusion of the

EVAR graft is rare. As a consequence, it is not as

well described in the literature as limb occlusion,

which is often included as a secondary outcome in

studies of novel EVAR devices7,8 and its presenta-

tion and management are described only in case re-

ports with treatment by combined surgical and

endovascular techniques.2,13

In the case of our patient, limb occlusion had

occurred as an early complication (within 9 months

of surgery) and was initially treated successfully

with a femorofemoral crossover graft. Complete

occlusion of the graft due to thrombus formation

subsequently occurred as a late complication

approximately 3 years after the initial endovascular

repair. The likely mechanism of this was turbulent

flow within the femorofemoral crossover graft

because of fibrointimal hyperplasia, with subse-

quent proximal propagation of the thrombus. The

postthrombolysis angiography showed typical ap-

pearances of fibrointimal hyperplasia (Fig. 2).

The acute occlusion was treated with thromboly-

sis. This is a recognized treatment for EVAR graft

limb thrombosis and acute limb or peripheral graft

occlusion but has not been reported in the treatment

of a completely thrombosed endograft. Thromboly-

sis is not without complications and carries inherent

risks of bleeding (minor, locally, and intracranial),

distal embolization of thrombotic material, and

anaphylaxis.20 In the present case, we concluded

that the risk of these side effects was likely to be

lower than the morbidity associated with emer-

gency axillobifemoral reconstruction, but this deci-

sion was reached after lengthy discussion between

the patient, admitting surgical team, and specialist

radiologists. Of note, the acute thrombus resolved

4 Case Report Annals of Vascular Surgery

with thrombolysis, but the treatment had no effect

on the established occlusion of the right limb of

the graft. We conclude that thrombolysis has a role

in the treatment of acute endograft occlusion, but

it is of lower utility if the patient presents late once

the thrombus has organized.

Anticoagulant therapy with warfarin has been

shown to bemore effective than aspirin alone at pre-

venting graft occlusion.21 The patient was consid-

ered to be high risk for further graft occlusion and

therefore initiated on warfarin. This will be

continued lifelong.

Thrombus formation in the body of an endograft

is a rare complication of EVAR. It may occur second-

ary to thrombus formation in a distal graft in the

presence of a predisposing factor such as fibrointi-

mal hyperplasia. Thrombolysis has a role in the

treatment of acute occlusion of endografts; howev-

er, the potential risks must be considered. With

the rarity of the presentation, it is unlikely to be

possible to conduct a randomized control trial study-

ing the effect of thrombolysis in this condition, and

thrombolysis should be considered on a case-by-

case basis.

REFERENCES

1. Greenhalgh RM, Brown LC, Kwong GP, et al. Comparison of

endovascular aneurysm repair with open repair in patients

with abdominal aortic aneurysm (EVAR trial 1), 30-day

operative mortality results: randomised controlled trial. Lan-

cet 2004;364:843e8.

2. Thurley PD, Glasby MJ, Pollock JG, et al. Endovascular man-

agement of delayed complete graft thrombosis after endo-

vascular aneurysm repair. Cardiovasc Intervent Radiol

2010;33:840e3.

3. EVAR Trial Participants. Endovascular aneurysm repair

versus open repair in patients with abdominal aortic aneu-

rysm (EVAR trial 1): randomised controlled trial. Lancet

2005;365:2179e86.

4. Maleux G, Koolen M, Heye S. Complications after endovas-

cular aneurysm repair. Semin Intervent Radiol 2009;26:

3e9.

5. Subramanian K, Woodburn KR, Travis SJ, et al. Secondary

interventions following endovascular repair of abdominal

aortic aneurysm. Diagn Interv Radiol 2006;12:99e104.

6. Cochennec F, Becquemin JP, Desgranges P, et al. Limb graft

occlusion following EVAR: clinical pattern, outcomes and

predictive factors of occurrence. Eur J Vasc Endovasc Surg

2007;34:59e65.

7. Mertens J, Houthoofd S, Daenens K, et al. Long-term re-

sults after endovascular abdominal aortic aneurysm repair

using the Cook Zenith endograft. J Vasc Surg 2011;54:

48e57.e2.

8. van Zeggeren L, Bastos Goncalves F, van Herwaarden JA,

et al. Incidence and treatment results of Endurant

endograft occlusion. J Vasc Surg 2013;57:1246e54. dis-

cussion 54.

9. Conway AM, Modarai B, Taylor PR, et al. Stent-graft limb

deployment in the external iliac artery increases the risk of

limb occlusion following endovascular AAA repair. J Endo-

vasc Ther 2012;19:79e85.

10. Blom AS, Troutman D, Beeman B, et al. Duplex ultrasound

imaging to detect limb stenosis or kinking of endovascular

device. J Vasc Surg 2012;55:1577e80.

11. Karthikesalingam A, Kumar S, Anandarajah JJ, et al. Predic-

tive value of peak systolic velocity for the development of

graft limb complications after endovascular aneurysm

repair. J Endovasc Ther 2012;19:428e33.

12. Eriksson MO, Wanhainen A, Nyman R. Intravascular ultra-

sound with a vector phased-array probe (AcuNav) is feasible

in endovascular abdominal aortic aneurysm repair. Acta

Radiol 2009;50:870e5.

13. Erzurum VZ, Sampram ES, Sarac TP, et al. Initial manage-

ment and outcome of aortic endograft limb occlusion.

J Vasc Surg 2004;40:419e23.

14. Moll FL, Powell JT, Fraedrich G, et al. Management of

abdominal aortic aneurysms: clinical practice guidelines of

the European society for vascular surgery. Eur J Vasc Endo-

vasc Surg 2011;41(Suppl 1):S1e58.

15. Polat A, Mert B, Gumus F, et al. Rare complication of EVAR:

thrombus in endograft. Eur J Vasc Endovasc Surg Extra

2011;22:e15e7.

16. Becquemin JP, Kelley L, Zubilewicz T, et al. Outcomes of

secondary interventions after abdominal aortic aneurysm

endovascular repair. J Vasc Surg 2004;39:298e305.

17. Byrne RM, Taha AG, Avgerinos E, et al. Contemporary out-

comes of endovascular interventions for acute limb

ischemia. J Vasc Surg 2014;59:988e95.18. Berridge DC, Kessel DO, Robertson I. Surgery versus throm-

bolysis for initial management of acute limb ischaemia.

Cochrane Database Syst Rev 2013;(6):CD002784.

19. Ronsivalle S, Faresin F, Franz F, et al. A new management

for limb graft occlusion after endovascular aneurysm repair

adding a vollmar ring stripper: the unclogging technique.

Ann Vasc Surg 2013;27:1216e22.20. Working Party on Thrombolysis in the Management of Limb

Ischaemia. Thrombolysis in the management of lower limb

peripheral arterial occlusionda consensus document.

J Vasc Interv Radiol 2003;14(9 Pt 2):S337e49.

21. Tangelder MJ, Lawson JA, Algra A, et al. Systematic review

of randomized controlled trials of aspirin and oral anticoag-

ulants in the prevention of graft occlusion and ischemic

events after infrainguinal bypass surgery. J Vasc Surg

1999;30:701e9.