Infected iliac pseudoaneurysm after uncomplicated percutaneous balloon angioplasty and (Palmaz) stent insertion: A case report and literature review Daniel J. Weinberg, MD, Dennis W. Cronin, MD, and Ar thur G. Baker, Jr., MD Philadelphia, Pa.

Percutaneous balloon angioplasty and endovascular stent placement are becoming c o m m o n techniques intended to reduce the need for surgical bypass procedures that may be more expensive or have higher morbidity rates. Prophylactic antibiotics are not currently used before stent placement in most centers even when implanted via the femoral route. Infectious complications have been rare. In the case presented here an infected c o m m o n iliac pseudoaneurysm occurred after percutaneous balloon angioplasty and stent placement. The literature is reviewed. (J VASC SURG 1996;23:162-6.)

Endovascular stents are a recent addition to the interventional armamentarium. These are intended to improve the major shortcoming of balloon an- gioplasty, namely, restenosis. After successful com- mon iliac percutaneous transluminal angioplasty (PTA) is performed, clinically apparent restenosis occurs in as many as 10% to 25% of cases often as soon as 3 to 6 months after the procedure) ,2 The 5-year cumulative patency rate after common iliac artery PTA exceeds 90% in several series. 3 Reste- nosis is believed to occur as a result of elastic recoil, suboptimal results of initial angioplasty, or both. Balloon-induced trauma may also predispose to platelet adhesion and smooth-muscle prolifera- t ion) '4 Beside restenosis, acute thrombosis may result. A variety of stems have been evaluated during the past decade for both coronary and peripheral use. Some of these include the Schneider WallStent, the Strecker Stent, the Gianturco-Roubin Stent, and the Palmaz Stent) ,s

The Palmaz Stent (Johnson & Johnson Interven- tional Systems; Warren, N.J.) is the only stent approved by the Food mad Drug Administration for peripheral use at this time. Unexpanded, it consists of

From the Department of Surgery, Presbyterian Medical Center, Philadelphia.

Reprint requests: Daniel J. Weinberg, MD, Suite 205, MOB, Presbyterian Medical Center, 39th & Market Sts., Philadelphia, PA 19104.

Copyright �9 1996 by The Society for Vascular Surgery and International Society for Cardiovascular Surgery, North Ameri- can Chapter.

0741-5214/96/$5.00 + 0 24/4/67731

162

a 30 mm long stainless steel mesh tube that is 3.4 mm in diameter and 0.015 mm thick. It is balloon expandable and was developed in the mid-1980s. ~,6

Preservation of benefit after stent placement has been high, frequently exceeding 70% to 80% at 3 to 5 years when the stent or stents were placed in the iliac artery for a jeopardized limb or moderate to severe claudication. 7-1~ Complications have been rare but include acute or subacute thrombosis, distal embolization, dissection, and extravasation. 1,7,~ 1,~2 At long-term follow-up restenoses have been observed as a result of intimal hyperplasia within or at the ends of the stent. 7A2 Repeat treatment by balloon angio- plasty has been successful in many cases. Access- related problems also occur, including thrombosis at the femoral access site, hematomas, and pseudoan- eurysms. Extravasation of contrast (after PTA), severely tortuous arteries, or densely, calcified arteries constitute the primary contraindications to iliac stent placement. 3'6 Case reports of infection have been described, usually after complicated or repeated stent placement at a given site. 6 The only stent-related infections identified after primary placement oc- curred after aortic stent insertion in one patient vcho subsequently resumed illicit intravenous drug use ~2 and Staphylococcus aureus sepsis in another patient (after iliac stent placement), which proved to be fatal. ~3 Perforation with infected pseudoaneurysm and clinical sepsis after uneventful PTA and stent placement have not been previously reported. Such a case will be presented and discussed.

His tory and hospital course. The patient is a

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Fig. 1. Poststent deployment radiograph.Arr0ws indicate position of stents.

51-year-old white woman who presented to her cardiologist with a chief report of severe bilateral calf claudication and atypical chest pain. Additionally she had a 40 pack-year history of cigarette smoking and hypercholesterolemia but no diabetes or other sig- nificant risk factors. Family history was noncontribu- tory. A cardiac cause of her chest pain was ruled out and esophageal causes elucidated. During this time her physician noted diminished groin and pedal pulses. Workup revealed high-grade aortic bifurca- tion and proximal common iliac stenoses.

PTA and placement of Palmaz stents was success- fully accomplished in the angioplasty suite via the femoral route. A total of three stents were placed: one into the left common iliac artery and two tandem stents into the aorta and right common iliac artery (Fig. 1). Placement of stents that make contact at the aortic bifurcation has been described previously. ~4,~s At the time this procedure was performed, prophy- lactic antibiotics were not administered, because they were not part o f the standard protocol, s-17 However, strict sterile technique was followed. The patient was discharged on the following day with minimal residual stenoses.

Two days after the procedure was performed, the patient returned with groin and abdominal pain associated with nausea and vomiting. Her tempera- ture was 104 ~ F, and blood cultures obtained at that time subsequently grew S. aureus in all aerobic bottles. A computed tomography scan of the abdo- men and pelvis was normal. Her white blood count

Fig. 2. Aortogram demonstrating large left common iliac artery pseudoaneurysm.

and erythrocyte sedimentation rate were both el- evated. Antibiotic therapy was initiated and a surgical consultation obtained for placement of long-term venous access, because the patient responded clini- cally to antibiotic therapy. The question of possible retroperitoneal complications was discussed, but the patient was discharged on antibiotic therapy.

She returned 1 week later with sepsis and abdominal and left flank pain. A computed tomog- raphy scan and angiography were performed, and a vascular surgery consultation was obtained. On examination, the patient was an obese 51-year-old white woman in moderate distress. Significant physi- cal findings were confined to her abdomen and legs. The abdomen was distended and soft, with dimin- ished bowel sounds. A tender palpable mass was present to the left of the umbilicus. Femoral and dorsalis pedis pulses were full and equal bilaterally. Petechiae were noted on her legs. Labor,'ltory exami- nation revealed a white blood cell count o f 14.2 K/cmm with 90% neutrophils and a normal hemat- ocrit level. Angiography revealed a pseudoaneurysm arising from the left common iliac artery (Fig. 2). Computed tomography scanning confirmed this finding (Fig. 3) and left ureteral obstruction resulting

JOURNAL OF VASCULAR SURGERY 164 Weinberg, Cronin, and Baker January 1996

Fig. 3. Computed tomography scan. Solid arrow identifies contrast-enhanced pseudoaneurysm. Hollow arrows demonstrate endovascular stents in-situ.

Fig. 4. Pathologic specimen. Palmaz stents containing fibropurulent exudate as seen when excised from right common iliac artery. Remnants of left common iliac intima (left).

in hydronephrosis. The lesion was presumed to be infected.

After a left ureteral stent was placed, the patient underwent right axillobifemoral grafting followed by a laparotomy in which the aorta, both iliac bifurca- tions, and the inferior mesenteric artery were con- trolled. The lesion was visible and palpable through the retroperitoneal fat and had the appearance o f an

infected retroperitoneal process with inflamed and thickened overlying soft tissue. After vascular control and reheparinization were performed, the aorta and both iliac bifurcations were clamped and opened. The stents were covered in fibropurulent exudate on the left and even on the right side (Fig. 4). All were removed, and the vessels were oversewn. Cultures of the pseudoaneurysm cavity and stents were obtained.

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Fig. 5. Operative photograph. Solid arrows illustrate proximal and distal limits of left common iliac artery defect. Hollow arrow identifies left ureter.

These failed to grow organisms, perhaps the result of several weeks of antibiotic therapy before surgical intervention. The left common iliac artery had disintegrated because of infection, and only frag- ments of intima remained (Fig. 5). The pseudoan- eurysm site was irrigated and drained. The abdomen was then closed.

The patient's postoperative course was quite stormy, complicated by severe adult respiratory distress syndrome and prolonged intubation. V/Q scanning did not suggest pulmonary embolization. She required mechanical ventilation, high positive end-expiratory pressure settings, and 100% oxygen initially, with extubation after 12 days. She ultimately left the hospital on the twenty-sixth postoperative day on an unrestricted diet, intravenous vancomycin, and low-dose warfarin (Coumadin).

Within a few months claudication recurred, be- cause the extraanatomic graft was patent but supplied inadequate flow for her active lifestyle. Reoperation was delayed for approximately 6 months, and then, after a thorough investigation for occult infection was completed, the patient was returned to the operating room, where an aortic bifurcation graft was placed to the iliac bifurcations. Her postoperative course was complicated by fever caused by bibasilar pneumonia that responded quickly to antibiotic therapy. She was discharged from the hospital on the ninth hospital day. She remains well 18 months after her initial surgical procedure.

DISCUSSION

The goal of the interventional vascular com- munity has been to reduce the invasive nature of procedures intended to reopen or bypass stenotic or occluded blood vessels. Previously the only tech- niques available to accomplish these goals included surgical bypass or endarterectomy. Increasingly, however, endovascular manipulation via balloon angioplasty with or without stent placement is attempted to avoid more invasive surgical proce- dures. Expected benefits include less morbidity and lower cost because of less loss of time from work and decreased use of expensive hospi- tal services and facilities. Hospital reimbursement for stents has thus far been poor, and many in- surance companies do not reimburse at all for these devices.

Before stent placement was performed, interven- tion consisted of balloon angioplasty without place- ment of a foreign body. Complications were infre- quent, consisting of access problems, thrombosis, restenosis, and distal embolization. Some cases of generally inconsequential contrast extravasation were also reported. Outcome, particularly f t r the com- mon iliac artery lesions, has been quite good, often comparable to surgical bypass. With the advent of endovascular stems, the interventional physician is now faced with a new, potentially more formidable problem with tremendous consequences. Not only are the long-term patency rates incompletely defined,

JOURNAL OF VASCULAR SURGERY 166 Weinberg, Cronin, and Baker January 1996

but infection is a greater risk. "Sterile technique" is but one important tool in prevention of prosthetic infection. Vascular surgeons have long been familiar with the dangers of implanting vascular prostheses that are at risk of becoming infected. Prophylactic antibiotics and the methods and timing by which they must be administered have been the subject of many trials and articles. Methods of skin and wound care have met with equal enthusiasm as modalities that can reduce the risk of prosthetic infection.

The mechanism of formation of the pseudoan- eurysm presented here cannot be known with cer- tainty. As described previously, innocuous guide wire and catheter perforations have occurred. If this had been the mechanism of action here, combined with a break in sterile technique, perhaps an infected pseudoaneurysm would have resulted in the absence of the stents. On the other hand, the fibropurulent exudate found at operation within the stents was presumably seeding the blood entering the ex- travascular cavity. This possibility would suggest that the stents became the source of ongoing infection once the initial contamination occurred. A benign bacteremia may have resulted without the stents in place.

It remains to be seen how often endovascular stent infection occurs. When implanted via the femo- ral route, the use of prophylactic antibiotic therapy may decrease the risk of this catastrophic complica- tion. In this era of cost containment and without a prospective trial to prove their benefit in this situa- tion, routine prophylactic antibiotics are likely to be deferred until further reports of infections dictate their use.

Accurate reporting and detailed cost analyses will be necessary if we are to determine the long- term risks of implanting these devices. Until that time the attitude that stent implantation is a benign, inexpensive alternative to surgery must be ques- tioned.

REFERENCES

1. Fischell TA, Stadius ML. New technologies for the treatment of obstructive arterial disease. Cathet Cardiovasc Diagn 1991;22:205-33.

2. Schatz RA. Introduction to intravascular stents. Cardiology Clinics 1988;6:357-72.

3. Palmaz JC, Garcia OJ, Schatz RA, et al. Placement of balloon-expandable intraluminal stents in iliac arteries: first 171 procedures. Radiology 1990;174:969-75.

4. Clowes AW, Reidy MA, Clowes MM. Mechanisms ofstenosis after arterial injury. Lab Invest 1983;49:208-15.

5. Zollikofer CL, Antonucci F, Pfyffer M, et al. Arterial stent placement with use of the Wallstent: midterm results of clinical experience. Radiology 1991;179:449-56.

6. Hallisey MJ, Parker BC, van Breda A. Current status and extended applications of intravascular stents. Curr Opin Radiol 1992;4:7-12.

7. Long AL, Page PE, Raynaud AC, et al. Percutaneous iliac artery stent: angiographic long-term follow-up. Radiology 1991;180:771-8.

8. Sapoval MR, Long AL, Raynaud AC, Beyssen BM, Fiessinger JN, Gaux JC. Femoropopliteal stent placement: long-term results. Radiology 1992;184:833-9.

9. Kidney D, Murphy J, Malloy M. Balloon-expandable intra- vascular stents in atherosclerotic iliac artery stenosis: prelimi- nary experience. Clin Radiol 1993;47:189-92.

10. Lembo NJ, Roubin GS. Intravascular stents. Cardiology Clinics 1989;7:877-94.

11. Monaghan D, Gaines PA. Case report: perforation of angioplasty balloon by Palmaz stem. Clin Radiol 1992;46: 133-4.

12. Diethrich EB. Endovascular treatment of abdominal aortic occlusive disease: the impact of stents and intravascular ultrasound imaging. Eur J Vasc Surg 1993;7:228-36.

13. Therase E, Soulez G, Cartier P, et al. Infection with fatal outcome after endovascular metallic stent placement. Radiol- ogy 1994;192:363-5.

14. Palmaz JC, Encarnacion CE, Garcia OJ, et al. Aortic bifurcation stenosis: treatment with intravascular stents. JVIR 1991;2:319-23.

15. Blum U, Gabelmann A, Redecker M, et al. Percutaneous recanalization ofiliac artery occlusions: results of a prospective study. Radiology 1993;189:536-40.

16. Bonn J, Gardiner GA, Shapiro MJ. Palmaz vascular stent: initial clinical experience. Radiology 1990;174:741-5.

17. RousseauH, JoffreJ, PuelJ, etal. Percutaneousvascular stent: experimental studies and preliminary clinical results in periph- eral arterial disease. Inter Angio 1987;6:153-61.