Stenting for - Europe PMC

Peripheral Interventions

Stenting for Abdominal Aortic Occlusive Disease Long-Term Results

Robert Martinez, MD Julio Rodriguez-Lopez, MD Edward B. Diethrich, MD

Key words: Aged; angioplasty, balloon; aorta,

We report the long-term results of abdominal aortic stenting in 24 patients who underwent stenting for atherosclerotic occlusive disease (16 stenoses, 6 occlusions, and 2 ulcerative plaques). The occlusions were treated initially with thrombolytic therapy, and all lesions were balloon dilated. Indications for stenting were: residual gradient (n= 10); recoil (n=7); dissection (n=2); and atherosclerotic debris (n=5). Thirty-eight Palmaz stents were implanted in the aorta, and 21 were implanted in the common iliac (n= 19) and external iliac (n=2) arteries. Technical and clinical success was 100%. Over a mean follow-up period of 48 months (range, 1 to 67 months), 2 patients died and 2 were lost to follow-up. Two patients developed symptoms referable to the aorta (at 43 and 67 months), and each was managed successfully via an endovascular approach. There was no in-stent restenosis. Life-table analysis showed a 100% cumulative primary patency at 5 years. We conclude that stenting for abdominal aortic occlusive disease appears to offer long-term patency slightly superior to that of classical surgical intervention. Aortic stents also do not appear to be subject to restenosis. Follow-up in a larger patient cohort is needed to confirm these observations. (Tex Heart Inst J 1997;24:15-22)

abdominallradiography;

aorta, abdominal/ultrasonography; aortic diseases! radiography; aortic diseases! therapy; aortic diseases! ultrasonography; arterial occlusive diseases/radiography; arterial occlusive diseases/therapy; arterial occlusive diseases/ ultrasonography; balloon dilatation; blood vessel prosthesis; female; follow-up

studies; human; male; prospective studies; stents; thrombolytic therapy; treatment outcome; vascular patency From: The Department of Cardiovascular and Endovascular Surgery, Arizona Heart Institute, Phoenix, Arizona 85006 Presented at the Texas Heart Institute's 3rd annual symposium on Peripheral Interventions for the Cardiovascular Specialist, held on 6-8 November 1996, at the Marriott Medical Center Hotel, Houston, Texas

Address for reprints: Edward B. Diethrich, MD, Arizona Heart Institute, 2632 N. 20th Street, Phoenix, AZ 85006 Texas Heart Instituteiournal

he infrarenal abdominal aorta and the iliac arteries are the most common sites of atherosclerotic occlusive disease. For more than 20 years, aortobifemoral bypass and aortoiliac endarterectomy were considered standard surgical management.1-3 However, in 1980, the 1st reports of successful aortic angioplasty appeared.4-6 Since that time, numerous investigators have presented short- and intermediate-term follow-up on aortic angioplasty,7-'8 but long-term reports have been few'117 until recently.19-22 In the late 1980s, intravascular stents began to demonstrate their now well-recognized ability to offer clinicians new therapeutic options in the treatment of a broad range of vascular diseases and angioplasty-induced defects. Particularly in the iliac arteries, stenting was shown to reduce the incidence of restenosis in comparison with balloon angioplasty.23 In 1990, on the basis of our success in stenting iliac stenoses, we began to offer stent therapy to patients with abdominal aortic lesions who were deemed at high risk for conventional surgery.24 We reported our preliminary experience with infrarenal abdominal aortic stenting in 1993.25 We now present an update on that original 24-patient cohort, with follow-up extending beyond 5 years.

Materials and Methods From January 1990 to June 1992, 24 patients (14 women and 10 men), mean age 67 years (range 50 to 88 years) were selected nonconsecutively and without randomization to participate in a protocol, approved by our Institutional Review Board, to evaluate the use of stents for the treatment of aortic occlusive disease. Patients were offered percutaneous endovascular procedures because of high surgical risk (22) or refusal of conventional surgery (2). All the patients were symptomatic, displaying severe intermittent claudication (19), rest pain (2), atherosclerotic microembolism (blue toe syndrome) (2), or ischemic distal ulcer (1). Before treatment, the mean ankle-brachial index (ABI) in the target limbs was 0.66. Abdominal aortic atherosclerotic disease was conAortic Stent Follow-up

15

firmed angiographically in all patients; the average stenosis was 76%, as measured on the arteriographic image by calipers. Six patients had total aortic occlusion, which was treated with thrombolytic therapy prior to angioplasty (Fig. 1). The techniques for this lysis and percutaneous aortic stenting have been reported in detail,24 but in brief the procedures were performed in an operative suite under epidural anesthesia using a standard bilateral percutaneous retrograde approach through dual 9-F sheaths (Cordis; Miami Lakes, Fla). After intravenous heparin administration, the lesion was crossed with 0.035-inch hydrophilic-coated guidewires (Glidewire® guidewire, Medi-tech®/Boston Scientific Corporation; Natick, Mass). In 2 cases, pulsed holmium-YAG laser energy (3.6 J/pulse at 10 Hz) was delivered to clear a channel through iliac occlusions that resisted guidewire passage. Lysis via the brachial or axillary artery began with an intraarterial infusion of a 250,000-U bolus of urokinase (Abbokinase, Abbott Laboratories; Abbott Park, Ill), followed by drip infusion of 40,000 to 100,000 U/h and a concomitant heparin drip (800 to 1200 U/h after a 1000- to 3000-U bolus). In all cases, the target sites were interrogated before and after angioplasty with either a 6-F, 20-MHz intravascular ultrasound (IVUS) catheter (Diasonics; Milpitas, Calif) or an 8-F, 30-MHz IVUS catheter (Cardiovascular Imaging Systems; Sunnyvale, Calif) to provide 2-dimensional (2D) imaging. Three-dimensional (3D) reconstruction was performed in selected cases with a real-time processing system (ImageComm Systems; Santa Clara, Calif). The most commonly used balloon for iliac and aortic dilations was the 8-mm x 8-cm Blue Max® balloon catheter (Medi-Tech®/Boston Scientific Corporation; Natick, Mass). For shorter lesions, balloons of appropriate size were chosen. Depending on the location and nature of the lesions in the aortoiliac segment, the kissing balloon technique was used when necessary to stabilize plaque at the aortic bifurcation. Final dilatation was judged satisfactory on the basis of optimal IVUS or fluoroscopic imaging (or both), together with resolution of the pressure gradient. If dissection, lesion recoil, intraluminal atherosclerotic debris, or an unresolved pressure gradient existed, aortic stenting was performed with 1 or more PALMAz. Balloon-Expandable P308 or P3008 stents (Johnson & Johnson's Cordis Corp. affiliate; Miami Lakes, Fla) mounted on 8-mm balloons. Early in the study, when larger (e.g., 14-mm-diameter) low-profile balloons were not yet available, it was common to use 2 balloons simultaneously to expand the stents adequately, after initial deployment. Satisfactory stent-to-vessel apposition was then verified by intravascular ultrasound, and adequate hemodynamic 16

Aortic Stent Follow-up

outcome was documented by obliteration of the pressure gradient. In 4 patients with aortobifemoral grafts, the lesions were at the level of the proximal anastomosis (3) or above the graft (1). In the remaining 20 patients, lesions were in the proximal portion of the infrarenal abdominal aorta (3), in the mid aorta (3), or in the distal aorta (14). A total of 38 PALMAZ stents were implanted in the abdominal aorta: 6 patients received 3 stents each, 2 had 2 stents each implanted, and the remaining 16 received a single device. Fifteen patients had significant iliac disease, for which 21 stents were implanted in the common (19) or external (2) iliac arteries. Four patients received dual iliac stents. One patient had a total of 6 stents implanted in the distal aorta and common iliac arteries. There were 3 access-related complications: 2 hematomas, which were treated with local compression, and a thrombus at the right common femoral artery puncture site in a patient with an aortobifemoral graft and femoropopliteal bypass. The latter complication was treated with open thrombectomy and patch-graft angioplasty of the proximal anastomosis of the femoropopliteal bypass. Thrombus was also encountered in a superficial femoral artery and in the right limb of an aortobifemoral bypass graft. In each case, open thrombectomy and femoral patch angioplasty were performed. After discharge, patients were placed on antiplatelet therapy (aspirin and dipyridamole) for a 3-month period. The average duration of hospitalization was 3 days (range, 1 to 8 days). There were no deaths, and clinical improvement was noted in all patients. The immediate postprocedural ABI rose to a mean value of 0.93 from the preprocedural mean of 0.66.

Follow-up Methodology, Definitions, and Statistical Analysis Patients were evaluated at 1, 6, and 12 months and every year thereafter by clinical examination and duplex scan with ABI measurement. Additional followup in some patients included arteriography with or without IVUS. Immediate technical success was defined as stent function judged adequate by means of angiographic and IVUS imaging (i.e., no residual stenosis, dissection, or extravasation of contrast) and resolution of the pressure gradient. Continued clinical success was defined as absence of symptoms referable to the treated site and a greater than 50% luminal diameter within the stented segment as seen on the imaging studies. Cumulative patency rates were calculated by the life-table method as defined by the Ad Hoc Committee on Reporting Standards of the Society for Vascular Surgery/North American Chapter, International Society for Cardiovascular Surgery.26 Data were analyzed using VascuBase" statisVolume 24, Number 1, 1997

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Fig. 1 A) Arteriogram of a chronic (>6-month) total occlusion in a patient with intermittent claudication of the hip and thigh. B) The occlusion was treated with urokinase infusion (80,000 units per hour) for 24 hours, followed by balloon dilation of the aorta and common iliac arteries. C) An intravascular ultrasound (IVUS) study after thrombolysis and balloon dilation detected the suboptimal luminal configuration. D) A repeat IVUS scan after aortic stent placement shows a more satisfactory luminal contour E) The control aortogram documented optimal results obtained after stenting in the aorta and in both common iliac arteries.

Texas Heart InstituteJournal

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17

Fig. 2 A) Preprocedural aortogram in a 66-year-old man showing multiple stenoses in the abdominal aorta, together with iliac and femoral artery disease. B) An arteriogram recorded 6 months after dual PALMAZ stent placement in the aorta and reconstructive surgery for the iliac and femoral lesions. C) Three and a half years after treatment, the abdominal aortic stents remain widely patent.

tical software (Consensus Medical Systems, Inc.; Seattle, Wash).

Results Follow-up data were available over a mean of 48 months (range, 1 to 67 months) (Fig. 2). Two of the 18


24 patients were lost to follow-up, and 1 patient with 3 stents died of cardiac failure at 4 months. Eight patients developed symptoms during the 67-month surveillance period. Of these, 6 had distal disease for which they underwent additional treatment, including 5 femoropopliteal bypasses and 7 endovascular procedures. Two patients (8%) required secondary aortic stent placement: 1 for a new lesion and the other for a partially closed stent. The cumulative primary patency by life-table analysis was 100% at 5 years (Table I). The 1st patient requiring a new procedure was a 70-year-old man who initially had a single stent implanted for severe stenosis in the mid portion of the abdominal aorta. He also received dual stents for left iliac artery occlusion. An arteriogram at 19 months revealed stenosis between the aortic stent and the bifurcation (Fig. 3A). The patient was asymptomatic, however, so no treatment was undertaken. At 43 months, bilateral claudication recurred owing to progression of the stenosis (Fig. 3B). A PALMAZ P308 stent was successfully implanted with a good clinical and angiographic result (Fig. 3C). Volume 24, iVumber 1, 1997

TABLE 1. Primary Patency for 24 Aortic Stent Patients No. Withdrawn Patent Due to Loss to Death Duration Follow-up

Cumula-

Interval Patency Rate

tive Patency (%)

Standard Error (%)

3

1.00

100

0

0

0

1.00

100

0

6

0

0

1.00

100

0

0

5

0

0

1.00

100

0

15

0

10

0

0

1.00

100

0

5

2

1

0

0

0.55

100

0

Interval (months)

No. of Stents at Risk

No. of Failed Stents

0-12

38

0

3

2

12-24

30

0

4

24-36

26

0

36-48

20

48-60 60-72

The 2nd patient, a 67-year-old woman with blue toe syndrome treated initially with 2 PALMAZ stents at the site of an ulcerated aortic plaque (Figs. 4A and 4B), experienced recurrence of her distal embolic symptoms at 67 months. The 67-month arteriogram showed no abnormality (Fig. 4C), and even the 2D IVUS image (Fig. 4D) was identical to her postprocedural control image. However, 3D reconstruction (Fig. 4E) demonstrated partial closure of the distal stent at its caudal end. A new PALMAZ stent was implanted, overlapping the distal stent (Fig. 4F) and reestablishing a satisfactory luminal contour.

Discussion Since the early 1960s, the standard treatment for aortoiliac occlusive disease has been endarterectomy or aortobifemoral bypass.27 In patients at high operative risk, however, alternatives to these surgical interventions may be preferable. Axillofemoral bypass grafting was introduced to provide lower-extremity inflow revascularization and has demonstrated acceptable primary and secondary patency rates.28 Percutaneous aortic angioplasty has been in use for 15 years, but long-term reports on more than a few cases have been scant until recently. 19-22 Today, the benefits of a percutaneous approach over conventional surgical intervention are well known: no general anesthesia, shorter hospitalization, speedier recovery, and reduced costs. Lower morbidity and mortality rates are commonly seen with percutaneous treatment, and in males with aortoiliac disease, a minimally invasive procedure obviates the potential for nerve damage and impotence that sometimes follows surgical intervention.29 The highly favorable results from multicenter investigations of the PALmAZ iliac stent led to exploration of stent application in other arterial locations. 030 As one of the centers participating in the iliac protocol, our team encountered a number of patients with lesions in the abdominal aorta (e.g., Texas Heart Instituteiournal

dissection, insufficient luminal diameter, and flowinhibiting atherosclerotic debris) similar to those seen in the iliac segment. In 1990, we began a protocol to study these patients, and our initial experience25 with this 24-patient cohort demonstrated the high degree of technical success (100%) we have now come to anticipate with infrarenal aortic stenting.3034 There were no deaths, and the few minor complications were access-related or secondary to thrombolysis. Intermediate-term clinical improvement was achieved in all patients, with amelioration in symptoms and ABIs. In our original report, we asked the question, "Will an aortic stent undergo restenosis necessitating repeated angioplasty or even formal operation?" At that time, we postulated that the large luminal dimensions of the distal aorta would make restenosis unlikely. We appear to have been correct; we have seen no evidence of in-stent restenosis-a considerable improvement over the 19/o arteriographic restenosis rate reported by Hedeman Joosten and colleagues'9 for their 38 aortic stenosis patients treated with angioplasty alone. However, the 2 patients in our group who required a new aortic intervention provided valuable lessons. One of these, a man with a narrowed native aorta between a mid-aortic stent and the bifurcation, shows the consequences of progressive disease. In such patients, whose aortic and iliac stents are not contiguously placed, the opportunity exists for a new lesion to develop. In similar situations we have encountered subsequently, if there is any evidence of disease near the aortic bifurcation, we place stents up to the iliac artery origins. In this way, we stabilize the bifurcation and hope to provide a more durable result. In the only long-term failure of primary patency, the patient presented with recurrence of her distal embolic symptoms. Arteriography could not reveal the source of the problem, and the 2D IVUS image looked unchanged from the postprocedural control. Aortic Stent Follow-up

19

Fig. 3 A) Arteriography 19 months after aortic stenting shows an asymptomatic stenosis in the unstented segment between the stent and the bifurcation. B) By 43 months, the stenosis was more severe, and bilateral claudication was present. Another Palmaz stent was implanted to successfully restore aortic continuity. C) An arteriogram performed 24 months after placement of the 2nd aortic stent shows sustained patency.

However, the 3D reconstruction showed the defect at the distal end of the caudad stent. Redilation and the implantation of a new stent improved the luminal integrity. 20


As this last case exemplifies, IVUS is a critical imaging technique for evaluating lesion characteristics, as well as determining arterial dimensions. Intraprocedurally, IVUS is invaluable in judging the need for stent placement.35 In more than 50% of the initial procedures, stents were placed in the aorta on the basis of the IVUS findings; the characteristics of many of these lesions were poorly visualized (or even undetected) by conventional angiographic imaging techniques, which would have limited our ability to treat them appropriately.25'36 During followup surveillance, IVJS can once again overcome the deficiencies of arteriography, particularly when aided by 3D reconstruction, which provides both longitudinal and volume views. Our results in this small population indicate that endovascular techniques can be used very successfully to treat aortoiliac occlusive lesions. The low morbidity and zero mortality rates surpass those of conventional open repair, and the 100% long-term patency rate, which exceeds the 80% to 90% 5-year rates for aortobifemoral grafting,'-3'27 supports our Volume 24, Number I., 1997

Fig. 4 A and B) Recurrence of distal embolic symptoms occurred 67 months after dual aortic stents were placed over an ulcerated distal aortic lesion. C) A 67-month arteriogram showed no abnormalities, nor did the 2-dimensional IVUS image (D, right) as compared with the postprocedural control (D, left). The longitudinal 3-dimensional view, however, demonstrated a portion of the distal end of the caudad stent to be away from the vessel wall (E, arrow). After redilation and stent expansion over the caudad stent, the aortic lumen regained its normal diameter (F, arrow). (Images A, B, and the post-stent image in D are from: Diethrich EB, Santiago 0, Gustafson G, Heuser RR. Preliminary observations on the use of the Palmaz stent in the distal portion of the abdominal aorta. Am Heart J 1993;125:490-501. Reprinted by permission of Mosby-Year Book, Inc.)

Texas Heart Institute Journal

contention that the majority of aortoiliac occlusive disease can be managed safely and effectively with percutaneous endovascular procedures. As we are seeing in our practice, these technically successful Aortic Stent Follow-up

21

and durable treatments are making aortobifemoral grafting nearly obsolete. However, our investigation of this promising stent application continues as we amass data on nearly 200 aortic stent patients.

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679-87. 23. Richter GM, Roeren TH, Noeldge G, Landwehr P, Allenberg JR, Kauffmann GW, Palmaz JC. [Initial long-term results of a randomized 5-year study: iliac stent implantation versus PTA]. [German] Vasa Suppl 1992;35:192-3. 24. Diethrich EB, Ravi R. Intraluminal stent implantation for the treatment of aortic graft stenosis. J Invasive Cardiol 1991;3:

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490-501. 26. Rutherford RB, Flanigan DP, Gupta SK, et al. Suggested standards for reports dealing with lower extremity ischemia. J Vasc Surg 1986;4:80-94. 27. Rutherford RB. Aortobifemoral bypass, the gold standard: technical considerations. Semin Vasc Surg 1994;7:11-6. 28. el-Massry S, Saad E, Sauvage LR, Zammit M, Davis CC, Smith JC, et al. Axillofemoral bypass with externally supported, knitted Dacron grafts: a follow-up through twelve years. J Vasc Surg 1993;17:107-15. 29. Cormio L, Edgren J, Lepantalo M, Lindfors 0, Nisen H, Saarinen 0, Ruutu M. Aortofemoral surgery and sexual function. EurJ Vasc Endovasc Surg 1996;11:453-7. 30. PalmazJC, Encarnacion CE, Garcia OJ, Schatz RA, Rivera FJ, Laborde JC, Dougherty SP. Aortic bifurcation stenosis: treatment with intravascular stents. J Vasc Interv Radiol 1991;2: 319-23. 31. el Ashmaoui A, Do DD, Triller J, Stirnemann P, Mahler F. Angioplasty of the terminal aorta: follow-up of 20 patients treated by PTA or PTA with stents. EurJ Radiol 1991;13:1137. 32. Long AL, Gaux JC, Raynaud AC, Faintuch JM, Pagny JY, Lacombe P, et al. Infrarenal aortic stents: initial clinical experience and angiographic follow-up. Cardiovasc Intervent

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