Radiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Published online before print February 19, 2004, 10.1148/radiol.2311030408
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
2311030408v1
231/1/243    most recent
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Murphy, T. P.
Right arrow Articles by Kim, H. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Murphy, T. P.
Right arrow Articles by Kim, H. M.
(Radiology 2004;231:243-249.)
© RSNA, 2004

Vascular and Interventional Radiology

Aortoiliac Insufficiency: Long-term Experience with Stent Placement for Treatment1

Timothy P. Murphy, MD, Nikki S. Ariaratnam, BA, Wilfred I. Carney, Jr, MD, Edward J. Marcaccio, MD, Jeffrey M. Slaiby, MD, Gregory M. Soares, MD and H. Myra Kim, ScD

1 From the Division of Vascular and Interventional Radiology, Department of Diagnostic Imaging (T.P.M., G.M.S.), and Department of Surgery (W.I.C., E.J.M., J.M.S.), Rhode Island Hospital, 593 Eddy St, Providence, RI 02903; Brown University Medical School, Brown Medical School, Providence, RI (N.S.A.); and Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor (H.M.K.). Received March 14, 2003; revision requested May 23; final revision received August 20; accepted September 4. Address correspondence to T.P.M.


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
RESULTS
DISCUSSION
 REFERENCES
 
PURPOSE: To establish and report the authors’ experience with the long-term outcomes of aortoiliac stent placement for treatment of chronic lower-extremity ischemia.

MATERIALS AND METHODS: Stents were placed in 505 arterial segment lesions in 365 patients who presented with symptoms of chronic leg ischemia between February 1992 and March 2001. The 505 treated lesions were 88 occlusions and 417 stenoses. Indications for stent placement were claudication in 312 (62%), rest pain in 107 (21%), ulcer in 67 (13%), and gangrene in 19 (4%) arterial segments. Patients were followed up for up to 105 months (mean, 33 months ± 27 [SD]).

RESULTS: Hemodynamic success was achieved in 484 (98%) of the 496 limbs for which postprocedural translesion pressure gradients were available. Mean ankle-brachial indexes improved from 0.53 ± 0.25 to 0.79 ± 0.23 (P < .001). Major complications were seen in 24 (7%) patients. Two patients (0.5%) died within 30 days after stent placement. Twenty (6%) of 355 patients underwent aortic or iliac bypass surgery during the follow-up period. Eight years after stent placement, primary patency was 74%; primary assisted patency, 81%; and secondary patency, 84%. Variables associated with better patency included stenosis (rather than occlusion), shorter lesion length, older age, and limb-threatening ischemia. At the last follow-up examination, 74% of the 466 limbs for which follow-up clinical status data were available were asymptomatic, 22% were associated with claudication, 3% were associated with rest pain, and 1% were associated with ischemic tissue loss. Five patients underwent amputation on the ipsilateral side after stent placement.

CONCLUSION: Findings from long-term experience with aortoiliac stent placement for treatment of chronic lower-extremity ischemia confirmed the procedure to be a durable, low-risk revascularization option.

© RSNA, 2004

Index terms: Arteries, stenosis or obstruction, 981.721, 984.721, 986.721 • Arteriosclerosis, 981.721, 984.721, 986.721 • Stents and prostheses, 981.1268, 984.1268, 986.1268


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
RESULTS
DISCUSSION
 REFERENCES
 
The management of aortoiliac insufficiency has evolved considerably since the Palmaz stent (Cordis/Johnson & Johnson, Warren, NJ) was introduced for use in peripheral arteries in the United States in 1991. Although stents initially were designed to be replacement treatments after failed balloon angioplasty, they are now used primarily to treat lesions that are not considered suitable for treatment with balloon angioplasty alone, including chronic iliac artery occlusions (1). Before iliac artery stent placement became available, bypass surgery (including aortofemoral, femorofemoral, and axillofemoral bypass) was the primary revascularization option for patients with diffuse atherosclerotic disease or chronic arterial occlusion. Aortofemoral bypass surgery was performed, if the patient’s health status was stable enough for her or him to undergo it, owing to the presumed superior durability of its results compared with the durability of the results of other options.

Aortofemoral bypass surgery reportedly results in 80%–90% patency at 5 and 10 years after the procedure (2); however, according to the results of a meta-analysis (3), it is also associated with a 30-day mortality rate of 3.3%. Aortoiliac stent placement is associated with lower morbidity and mortality compared with aortofemoral bypass surgery, and early results suggest that it results in excellent patency over the short term (4–7). However, one opinion is that a revascularization procedure must demonstrate long-term result durability (ie, of at least 4 or 5 years) to be established as a viable treatment option (8), and we believe that this criterion is reasonable. Thus, the purpose of our study was to establish and report our experience with the long-term outcomes of aortoiliac stent placement for the treatment of chronic lower-extremity ischemia.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
DISCUSSION
 REFERENCES
 
Patient Population
This retrospective study was approved by the institutional review board of Rhode Island Hospital, which waived the requirement for informed patient consent. Patients were considered good candidates for aortoiliac stent placement if they had symptoms of chronic lower-limb ischemia (ie, intermittent claudication, rest pain, ischemic ulceration, and/or gangrene) and an aortic or iliac artery stenosis with a mean pressure gradient higher than 5 mm Hg. Patients with acute symptoms such as blue-toe syndrome were excluded from the study.

Between February 10, 1992, and March 14, 2001, 505 stent placement procedures were performed in 365 patients. Five hundred limbs of 360 patients were treated with stents placed in iliac artery (ie, common iliac artery, external iliac artery, or both; 23 with additional aortic stents) segments, and five limbs of five patients were treated with stents placed in aortic segments only. One hundred forty patients underwent bilateral iliac artery stent placement. The patients’ demographic data, risk factors for cardiovascular disease, and presenting symptoms are given in Table 1. The patients who presented with intermittent claudication reportedly had a mean maximum walking distance capability of 150 yards ± 100 (SD).


View this table:
[in this window]
[in a new window]

  		TABLE 1. Patient Characteristics and Presenting Symptoms

 
Stent Placement Procedures
The stent placement procedures were performed by any of five board-certified radiologists, all of whom also have subspecialty certification in vascular and interventional radiology. At the beginning of the 10-year study period, one of these radiologists had 9 years, one had 7 years, two had 6 years, and one had 1 year of experience. Two authors (T.P.M., G.M.S.) were among those who performed many of the procedures. In addition, radiology fellows and residents usually had some involvement in the procedures. Most of the stent placement procedures were not performed with use of a specific protocol, and the techniques varied somewhat. In general, heparin was administered as a bolus (50–100 IU/kg) before the stent was placed. For prolonged procedures (ie, >2 hours), heparin was infused at a rate of 10–20 IU/kg/hr. The patients took one 325-mg aspirin tablet daily, beginning the night before the procedure, and continued taking them indefinitely.

Three hundred forty-four limbs were treated with self-expanding stents, 119 were treated with balloon-expanding stents, and 42 were treated with both types of stents. The following self-expanding stents were used: Wallstent (Boston Scientific, Natick, Mass), Wallgraft (Boston Scientific), and Smart Stent (Cordis/Johnson & Johnson). The following balloon-expanded stents were used: Palmaz stent, Corinthian stent (Cordis/Johnson & Johnson), and AVE-Bridge stent (Medtronic, Minneapolis, Minn). In general, the stents placed in the external iliac arteries were dilated to 7 or 8 mm in diameter (mean, 7.6 mm ± 2.3) and those placed in the common iliac arteries were dilated to 8–10 mm in diameter (mean, 8.0 mm ± 0.9).

Stents were placed for 88 occlusions and 417 hemodynamically significant (mean pressure gradient > 5 mm Hg or >50% of diameter narrowed) stenoses larger than 3 cm. In general, occlusions involved the entire occluded common iliac or external iliac artery or both entirely occluded arteries. Twenty-eight patients had aortic stents and included 23 patients with both aortic and iliac artery stents placed and five with only aortic stents placed. In 173 patients, stents were placed in both common and external iliac arteries; in 201 patients, stents were placed in only the common iliac artery; and in 126 patients, stents were placed in only the external iliac artery (23 patients with aortic stents are included in this group).

Ankle-brachial indexes (ABIs) and intravascular pressures were measured before and after the stent placement procedures. Early in our experience, thrombolysis was performed to treat chronic occlusions at the interventionalist’s discretion. It is our usual practice to perform iliac artery revascularization and infrainguinal revascularization, with iliac artery revascularization usually performed first. The numbers of patients who underwent concurrent or subsequent infrainguinal bypass surgery were not determined; however, this procedure is not commonly performed at our institution.

Follow-up Methods
The asymptomatic patients were followed up according to the routine practice of the treating physician. Usually, the first follow-up visit was within 1 month after the stent placement procedure, and the patients were seen biannually thereafter. Many patients were not followed up for more than 3 or 4 years postoperatively if their symptoms had improved, as compared with their baseline symptoms, or stabilized during this period. Clinical follow-up usually involved determining the recent (ie, since the stent placement) medical history, performing a pulse examination, and obtaining ABIs with or without pulse volume recordings. If other examinations yielded more accurate data on the loss of primary patency than the recent medical history and the ABI, then the data collected from these tests were recorded as well.

Follow-up data on 491 limbs (97%) in 355 patients were available, and a total of 1,293 follow-up evaluations, or an average of 3.6 examinations per patient, were performed. The last examination or method used to determine the length of follow-up for each of the 491 limbs was clinical examination with noninvasive testing (ie, ABI and pulse volume recording) for 279, arteriography for 26, duplex ultrasonography (US) for 24, outpatient office records for 146, and hospital inpatient records for 16 limbs. ABIs were available at the time of the last evaluation for 469 (96%) of the 491 treated limbs. A mean of 54 limbs ± 22 were treated annually from 1992 through 2000. A breakdown of the number of limbs treated per year and the running cumulative total numbers of limbs is presented in Table 2.


View this table:
[in this window]
[in a new window]

  		TABLE 2. Number of Limbs Treated with Stent Placement per Year and Cumulative Totals

 
Definitions
Hemodynamically, technical success was defined as a mean translesion pressure gradient of 5 mm Hg or lower after stent placement. Major complication was defined as any event, regardless of how minimal, not routinely observed after stent placement that required treatment with any therapeutic intervention. Loss of patency was defined, according to accepted reporting standards (9), as a decrease in the ABI of more than 0.10, unless the results of other examinations, such as duplex US or arteriography, demonstrated patency of the stent-dilated arterial segment without significant stenosis. The criteria for defining significant stenoses according to findings of these examinations include a doubling of peak systolic velocity just distal to the lesion at US or either a stenosis of greater than 50% in diameter or a mean pressure gradient higher than 5 mm Hg at arteriography. Stenoses contiguous with the stent that were detected during the follow-up period were considered to be stent related (ie, assisted patency loss), and the associated loss of patency was assigned accordingly. Any occlusion of either the stent-dilated vessel or the continuous artery proximal or distal to the placed stent was considered a stent failure, even if the stent-dilated segment was not considered to be responsible for the vessel occlusion. The patency definitions of Rutherford et al (9) were used. The patients who required a surgical intervention for revascularization and those who experienced a loss of primary patency owing to stent stenosis or thrombosis and did not undergo surgical revascularization were considered to have lost secondary patency (9).

Statistical Analyses
Initially, the unit of analysis was limb rather than patient; with this approach, the independence of the individual limbs of each patient was assumed. The final multivariate analysis (described later in this section), however, was performed by using a method with which within-patient correlation is accounted for. In this analysis, technical success was defined as described earlier and immediate technical success was graded by using the clinical grading system of Rutherford et al (9). Differences between continuous variables after stent placement and baseline values such as ABI and translesion pressure gradient were compared by using the paired t test. P values of .05 or less were considered to indicate statistical significance.

The distributions of time to primary, assisted, and secondary patency were calculated by using the Kaplan-Meier method and presented according to accepted patency reporting standards (9). The time to loss of patency (event) was calculated as the time from stent placement to the acute event indicating loss of patency. If the limb was judged to be patent until the last recorded visit, then the event was considered censored at the time of the last visit. If the loss of patency was determined during a follow-up visit without an acute event having occurred, then the time of patency loss was judged to be the midpoint of the interval between the last documented visit when the stent-dilated segment was determined to be patent and the visit when the loss of patency was determined. This method of imputing the time of the patency loss event as the midpoint of the interval may yield an under- or overestimated patency rate if the imputation systematically leads to an under- or overestimation of the time of patency loss. Because there was no known reason to believe that any systematic bias was associated with this method of imputation, we performed the analysis by considering these data to be indicative of failure at the midpoint rather than interval censored so that we could use an analytic model that was popular and easier to understand but did not allow for interval-censored data. We later checked the adequacy of this assumption by using a model that allows for interval-censored data and described the findings briefly (in Results section).

To screen for variables that affected primary patency, we used the log-rank test to assess dichotomous or categorical potential predictors, such as presence of a particular comorbid condition or different presenting indications. The Cox proportional hazards model was used to assess the independent effect of a predictor of primary patency loss while adjusting for the effects of other predictors or covariates. The final model was obtained by using stepwise selection, and although P values of .05 or less were considered to indicate statistical significance, the final model included variables that were thought to be associated with primary patency, regardless of their statistical significance.

Proportional hazard assumptions were checked graphically by using a log-log survival plot for discrete predictors and were based on the analysis of Schoenfeld residuals for the overall model and for each variable included in the final model. Within-patient correlation was possible owing to the existence of data on up to two limbs per person, and to account for this, we fit the Cox proportional hazards model with frailty and found the frailty variance to be significant. Therefore, the results from the Cox proportional hazards model with frailty are reported as our final results.

Data were collected by two authors (N.S.A., T.P.M.) by using case report forms and were entered and stored in a computerized database (Access 2000; Microsoft, Redmond, Wash). The data used to determine technical success, immediate clinical success, and patency rates were from medical records and were not adjudicated. Statistical analyses were performed by using SAS, version 8.02 (SAS Institute, Cary, NC) and Stata, version 8.1 (Stata, College Station, Tex) software.


   RESULTS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
DISCUSSION
 REFERENCES
 
Immediate Technical and Clinical Results
The postprocedural translesion pressure gradients of 496 arterial segments were available. Four hundred eighty-four of these segments had a mean pressure gradient of 5 mm Hg or lower, yielding a hemodynamic success rate of 98%. With regard to the 417 lower extremities with arterial stenosis, there was a statistically significant mean reduction in pressure gradient, of 13 mm Hg (P < .001), during the pre– to post–stent placement interval in 407 segments in which both gradients (ie, pre– and post—stent placement) were measured. For 84 chronic arterial occlusions, the mean post–stent placement pressure gradient was 1.5 mm Hg ± 1.5 (SD), and no patient had a mean pressure gradient of 5 mm Hg or higher after stent placement. A mean of 1.4 stents ± 0.6 per treated limb were placed. The mean length of the stent-dilated arteries was 5.9 cm ± 3.3. The mean ABI improved from 0.53 ± 0.25 to 0.79 ± 0.23, with a mean intralimb change in ABI of 0.26 ± 0.22 for the 496 arterial segments.

According to the criteria of Rutherford et al (9), 95% (n = 473) of 498 limbs showed some improvement after the procedure, and 80% (n = 397) showed an improvement in ABI of at least 0.10, with improvement of at least one symptom category (Table 3). Only 30 (6%) limbs were unchanged or worse after the procedure. Most of the patients who were judged to have worse symptoms according to this system had ABI decreases of less than 0.10 compared with their indexes before the stent placement procedure, with no change in their symptoms. Only 1% (n = 6) of limbs had an ABI decrease of 0.10 or greater from the baseline value after the procedure.


View this table:
[in this window]
[in a new window]

  		TABLE 3. Clinical Results Based on Scale Criteria of Rutherford et al

 
There were no procedure-related (ie, 24 hours postoperatively) deaths, but there were two deaths within 30 days. Thus, there was a 30-day mortality rate of 0.5%. One of the patients who died within 30 days was an 85-year-old man with metastatic cancer who was treated for an iliac artery occlusion and a nonhealing ulcer. He died of pneumonia 21 days after the stent placement procedure. The other patient was a 78-year-old man with rest pain who underwent uncomplicated iliac artery stent placement but continued to have severe rest pain and died 2 days after the stent placement procedure while waiting to undergo infrainguinal bypass surgery. Major complications were observed in 24 (7%) patients and included acute thrombosis of the stent, distal embolization, arterial rupture, and acute renal failure. Surgery to address the complications was required in six (2%) patients.

Long-term Results
Patients were followed up until March 22, 2002. Data on the follow-up beyond hospital admission (when the procedure was performed) were available for 355 (97%) patients (491 limbs). For those patients who were not lost to follow-up, the mean follow-up period was 33 months ± 27. Patients were followed up for a maximum of 105 months.

Twenty (6%) of the 355 patients for whom follow-up data were available underwent aortic or ipsilateral iliac bypass surgery during the follow-up period. Five (1%) patients underwent amputation on the ipsilateral side after the stent placement procedure. Four of these five patients presented with symptoms of limb-threatening ischemia. The overall limb salvage rate in the patients who presented with symptoms of limb-threatening ischemia was 98% (189 of 193 patients). One patient who presented with intermittent claudication developed a stent-related arterial infection and required above-knee amputation. Thus, the rate of limb loss in the patients with claudication was 0.3% (one in 312 patients). Five other known deaths occurred during the follow-up period.

For the 469 limbs for which there were follow-up ABI data, the mean ABI remained stable at 0.81 ± 0.21. Of the 466 limbs for which the clinical status was noted at last follow-up, 74% (n = 345) were asymptomatic and 22% (n = 102) were associated with intermittent claudication. Only 19 (4%) limbs were associated with symptoms of limb-threatening ischemia.

Stent-induced Patency
Patency results are presented in Table 4. Eight years after stent placement, primary patency was 74% (standard error, 3%); primary assisted patency, 81% (standard error, 3%); and secondary or cumulative patency, 84% (standard error, 3%). From the data in Tables 4 and 2, it is clear that there were many limbs for which patency was not accounted for. For example, after the first year, we reported the secondary patency rate for 366 limbs, whereas a total of 505 limbs were treated; therefore, there were 139 treated limbs for which there was less than 1 year of follow-up. Sixty-two of these 139 limbs (in 48 patients) were treated less than 1 year before this retrospective review and thus could not have been followed up for 1 year at that time. Therefore, there were 77 limbs without 1-year follow-up data because of death or loss to follow-up. For the total of 443 treated limbs for which there was an interval of at least 1 year between treatment and this review, we have 1-year patency data on 366 patent limbs and 28 occluded limbs. This is a total of 394 limbs, meaning that 89% of data were accounted for at 1 year; these data indicate satisfactory follow-up.


View this table:
[in this window]
[in a new window]

  		TABLE 4. Patency Resulting from Aortoiliac Stent Placement Procedures

 
The following variables were screened for their effect on time to loss of primary patency: patient age and sex, hypertension, hypercholesterolemia, coronary artery disease, cerebrovascular disease, chronic renal failure, diabetes mellitus, smoking history, ABIs before and after stent placement, within-limb ABI change, mean gradients before and after stent placement, within-limb gradient change, stent-dilated arterial segment length, final stent inflation diameter, stent type (ie, balloon expanding, self expanding, or both), and type of artery with stent. The location of the artery was analyzed in two ways: first, by classifying stent location as in the aorta, in a common iliac artery, in an external iliac artery, in both common and external iliac arteries, or in the common and external iliac arteries and the aorta; and then by using a separate model with stent location classified as in or not in the external iliac artery.

Results of the best-fitting Cox proportional hazards model for primary patency, with frailty to adjust for within-patient correlation, are given in Table 5. The frailty variance was significant (P < .01), indicating within-patient correlation. After the within-patient correlation and the other covariates were accounted for, the risk of losing primary patency was estimated to have increased more than threefold when the length of the treated segment was greater than 7.5 cm. On the other hand, the risk decreased significantly (P = .003) with age. Relative to the clinical indication of claudication, rest pain was associated with a lower risk of primary patency loss. Ischemic ulceration and gangrene also tended to be associated with a lower risk—although not a significantly lower one—compared with claudication. The model also included other variables such as patient sex, initial symptoms of occlusion at presentation, and involvement of external iliac artery only. The variable of external iliac artery was included because the size of the estimated hazard ratio was robust to the inclusion and exclusion of other variables. The stents placed in only an external iliac artery tended to be associated with lower risk compared with the stents placed in only a common iliac artery or in both a common iliac artery and either an external iliac artery or the aorta. (Note that the five patients in whom only an aortic stent was placed were excluded from this final model.)


View this table:
[in this window]
[in a new window]

  		TABLE 5. Cox Proportional Hazards Multivariate Model Results: Variables Associated with Primary Patency of 478 Limbs

 
In the screening analysis, we observed a trend toward increased risk of patency loss with increasing number of involved arterial segments, but this trend disappeared after we adjusted for other variables. To assess whether imputing the time of the patency loss event as the midpoint of the interval biased our results when, in fact, only the interval of the occurrence of the event was known, we refit the model by using the interval-censored data and a parametric Weibull model, which can be used with interval-censored data. We found the results to be similar between the two methods.


   DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
DISCUSSION
REFERENCES
 
Peripheral vascular disease is common: It is present in 12%–29% of older individuals (10–13). Seventy percent of individuals with arterial insufficiency present with intermittent claudication (14). Although superficial femoral artery obstruction is more common than aortoiliac obstruction (15), most patients with superficial femoral artery obstruction are asymptomatic (15–17). Aortoiliac obstruction is associated with more ischemic muscle mass (18) and often with severe symptoms.

Intraarterial stent placement to treat atherosclerotic obstruction was proposed by Dotter and Judkins in 1964 (19). To our knowledge, the first described use of percutaneously implanted stents in human arteries is that of the Wallstent in coronary, iliac, and femoral arteries described in the 1987 report of Sigwart et al (20). Shortly thereafter, the results achieved with the Palmaz stent in iliac arteries were reported (5). Stents were first approved by the U.S. Food and Drug Administration for use in iliac arteries in the United States in 1991.

Although initially introduced as a method to salvage failed balloon angioplasty, stents have been proved to allow the indications for percutaneous interventions to be extended to include treatment of lesions that previously were not considered suitable for balloon angioplasty (21), and these devices are now accepted as a primary therapy. These advances occurred in part because of the morbidity and mortality associated with the conventional treatment approach, aortofemoral bypass surgery.

The weighted 30-day mortality rate with aortofemoral bypass surgery reported in 13 series published since 1978 (6,22–33), with 5,249 patients reportedly treated for aortoiliac insufficiency, is 4%, which is not very different from the rate of 3.3% observed when the data are limited to those published since 1993 (23,25,28,29,34,35). The 30-day mortality rate of 0.5% observed in the present study compares favorably with these previously obtained surgical results. Given a background survival rate for patients with peripheral vascular disease of approximately 70% at 5 years (22) and assuming a constant monthly hazard of 0.0054 that corresponds to the observed 30-day mortality rate, we estimated a 5-year survival rate of 72%, which is similar to previously reported background mortality rates for patients with lower-extremity peripheral arterial disease (36).

Although claudication has been considered a controversial indication for surgical revascularization (37), the 0.3% rate of limb loss that we observed in patients who presented with claudication was much lower than that expected on the basis of the natural history of the condition without revascularization: approximately 5% within 5 years (38).

Patency rates of 82%–91% at 5 years and of 76%–80% at 10 years have been reported with aortofemoral bypass surgery (27,30–32,35). Our patency results indicate—contrary to what was previously assumed (39)—that the long-term patency of aortoiliac arteries treated with stents is comparable to that resulting from bypass surgery.

The results of multivariate analyses of patient characteristics that favor stent-induced patency are confusing. Many variables that were associated with the loss of primary patency in our experience are similar to those previously described in association with stent placement and balloon angioplasty (6,7,40–43). However, considerable inconsistency exists. For example, after we adjusted for other variables, intermittent claudication and younger age were associated with a greater risk of recurrent stenosis. However, in one study involving 288 patients, younger age and lower severity of ischemia were reportedly associated with less risk of recurrent stenosis (40).

The results of adjusted analysis from one institution suggest that women have poorer stent-induced patency (42). In many other experiences (6,40,41), however, including our own, this has not been observed. The observation that individuals with external iliac artery stents do not have worse outcomes than those with common iliac artery stents has been previously described (41) but is contrary to prior results with balloon angioplasty of external iliac versus common iliac arteries (43) and to one other experience with stents (42). It should be emphasized that the patient populations described in published studies differ and that some of the correlations can be attributed to the exploratory nature of this type of post hoc data analysis.

This series was limited by its retrospective nature and by the lack of a randomly selected control group. However, aortoiliac artery stent placement has been accepted clinically, and randomizing patients to stent placement or aortofemoral bypass surgery at this time—due to the acceptance of aortoiliac stent placement clinically—is unlikely to be done and might be considered unethical (44). Since this study was retrospective, the follow-up protocol was not uniform; however, the follow-up data were sufficient for analysis: Few patients were lost to follow-up, and data on 89% of the patients who were eligible for follow-up at 1 year were collected. Follow-up of asymptomatic patients for more than 4 or 5 years was not a rule in this study: Because of the relatively short period in which recurrent stenosis occurs, asymptomatic patients usually are not followed up longer than that. It has been stated that a follow-up period of at least 4 or 5 years after a vascular procedure is necessary to determine the merit of the procedure (8), and now that stents have been available in the United States for more than 10 years, it is clear that the long-term clinical results are comparable to those of aortofemoral bypass surgery, with a much lower risk of associated morbidity or mortality.


   FOOTNOTES
 
Abbreviation: ABI = ankle-brachial index

Author contributions: Guarantor of integrity of entire study, T.P.M.; study concepts, all authors; study design, H.M.K., N.S.A., T.P.M.; literature research, N.S.A., T.P.M.; clinical studies, T.P.M., G.M.S.; data acquisition, T.P.M., N.S.A., G.M.S., W.I.C., E.J.M., J.M.S.; data analysis/interpretation, H.M.K., T.P.M., N.S.A.; statistical analysis, H.M.K., T.P.M., N.S.A.; manuscript preparation, G.M.S., T.P.M., N.S.A.; manuscript definition of intellectual content, T.P.M.; manuscript editing, G.M.S., W.I.C., E.J.M., J.M.S., H.M.K.; manuscript revision/review and final version approval, all authors


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS
DISCUSSION
 REFERENCES
 

  1. Vorwerk D, Guenther RW, Schurmann K, Wendt G, Peters I. Primary stent placement for chronic iliac artery occlusions: follow-up results in 103 patients. Radiology 1995; 194:745-749.[Abstract/Free Full Text]
  2. DeWeese JA, Leather R, Porter J. Practice guidelines: lower extremity revascularization. J Vasc Surg 1993; 18:280-294.[CrossRef][Medline]
  3. de Vries SO, Hunink MG. Results of aortic bifurcation grafts for aortoiliac occlusive disease: a meta-analysis. J Vasc Surg 1997; 26:558-569.[CrossRef][Medline]
  4. Martin EC, Katzen BT, Benenati JF, et al. Multicenter trial of the wallstent in the iliac and femoral arteries. J Vasc Interv Radiol 1995; 6:843-849.[Medline]
  5. Palmaz JC, Richter GM, Noeldge G, et al. Intraluminal stents in atherosclerotic iliac artery stenosis: preliminary report of a multicenter study. Radiology 1988; 168:727-731.[Abstract/Free Full Text]
  6. Sapoval MR, Chatellier G, Long AL, et al. Self-expandable stents for the treatment of iliac artery obstructive lesions: long-term success and prognostic factors. AJR Am J Roentgenol 1996; 166:1173-1179.[Abstract/Free Full Text]
  7. Murphy TP, Webb MS, Lambiase RE, et al. Percutaneous revascularization of complex iliac artery stenoses and occlusions with use of Wallstents: 3-year experience. J Vasc Interv Radiol 1996; 7:21-27.[Medline]
  8. Hallett JW, Jr. Back to the future of vascular surgery: why certain procedures become obsolete. J Vasc Surg 1997; 25:791-795.[CrossRef][Medline]
  9. Rutherford RB, Baker JD, Ernst C, et al. Recommended standards for reports dealing with lower extremity ischemia: revised version. J Vasc Surg 1997; 26:517-538.[CrossRef][Medline]
  10. Criqui MH, Fronek A, Barrett-Connor E, Klauber MR, Gabriel S, Goodman D. The prevalence of peripheral arterial disease in a defined population. Circulation 1985; 71:510-515.[Abstract/Free Full Text]
  11. Hirsch AT, Criqui MH, Treat-Jacobson D, et al. Peripheral arterial disease detection, awareness, and treatment in primary care. JAMA 2001; 286:1317-1324.[Abstract/Free Full Text]
  12. Kannel WB, McGee DL. Update on some epidemiologic features of intermittent claudication: the Framingham Study. J Am Geriatr Soc 1985; 33:13-18.[Medline]
  13. Droller HP. Cardiovascular disease in a random sample of elderly people. Br Heart J 1953; 15:199-204.
  14. Hertzer NR. The natural history of peripheral vascular disease: implications for its management. Circulation 1991; 83:I12-I19.
  15. Martin EC. Transcatheter therapies in peripheral and noncoronary vascular disease: introduction. Circulation 1991; 83:I1-I15.
  16. Widmer LK, Ludin H. Examination of peripheral arteries: its importance for the early detection of atherosclerosis. Thromb Diath Haemorrh Suppl 1966; 21:357-369.[Medline]
  17. Widmer LK, Biland L, Zemp E. Epidemiology of arterial occlusive disease: peculiarities in advanced age. Z Gerontol 1985; 18:2-6.[Medline]
  18. Pernow B, Zetterquist S. Metabolic evaluation of the leg blood flow in claudicating patients with arterial obstructions at different levels. Scand J Clin Lab Invest 1968; 21:277-287.[Medline]
  19. Dotter CT, Judkins MP. Transluminal treatment of arteriosclerotic obstruction: description of a new technic and a preliminary report of its application. Circulation 1964; 30:654-670.[Abstract/Free Full Text]
  20. Sigwart U, Puel J, Mirkovitch V, Joffre F, Kappenberger L. Intravascular stents to prevent occlusion and restenosis after transluminal angioplasty. N Engl J Med 1987; 316:701-706.[Abstract]
  21. Pentecost MJ, Criqui MH, Dorros G, et al. Guidelines for peripheral percutaneous transluminal angioplasty of the abdominal aorta and lower extremity vessels: a statement for health professionals from a special writing group of the Councils on Cardiovascular Radiology, Arteriosclerosis, Cardio-Thoracic and Vascular Surgery, Clinical Cardiology, and Epidemiology and Prevention, the American Heart Association. Circulation 1994; 89:511-531.[Free Full Text]
  22. McDaniel MD, Cronenwett JL. Basic data related to the natural history of intermittent claudication. Ann Vasc Surg 1989; 3:273-277.[Medline]
  23. Erdoes LS, Bernhard VM, Berman SS. Aortofemoral graft occlusion: strategy and timing of reoperation. Cardiovasc Surg 1995; 3:277-283.[CrossRef][Medline]
  24. Prendiville EJ, Burke PE, Colgan MP, Wee BL, Moore DJ, Shanik DG. The profunda femoris: a durable outflow vessel in aortofemoral surgery. J Vasc Surg 1992; 16:23-29.[CrossRef][Medline]
  25. Schneider JR, Besso SR, Walsh DB, Zwolak RM, Cronenwett JL. Femorofemoral versus aortobifemoral bypass: outcome and hemodynamic results. J Vasc Surg 1994; 19:43-57.[Medline]
  26. Piotrowski JJ, Pearce WH, Jones DN, et al. Aortobifemoral bypass: the operation of choice for unilateral iliac occlusion? J Vasc Surg 1988; 8:211-218.[CrossRef][Medline]
  27. Crawford ES, Bomberger RA, Glaeser DH, Saleh SA, Russell WL. Aortoiliac occlusive disease: factors influencing survival and function following reconstructive operation over a twenty-five-year period. Surgery 1981; 90:1055-1067.[Medline]
  28. Hans SS. Concurrent audit of early outcome for 1,617 consecutive arterial reconstructions. Surg Gynecol Obstet 1993; 176:382-386.[Medline]
  29. Huber TS, Harward TR, Flynn TC, Albright JL, Seeger JM. Operative mortality rates after elective infrarenal aortic reconstructions. J Vasc Surg 1995; 22:287-294.[CrossRef][Medline]
  30. Brewster DC, Darling RC. Optimal methods of aortoiliac reconstruction. Surgery 1978; 84:739-748.[Medline]
  31. Poulias GE, Doundoulakis N, Prombonas E, et al. Aorto-femoral bypass and determinants of early success and late favourable outcome: experience with 1000 consecutive cases. J Cardiovasc Surg (Torino) 1992; 33:664-678.[Medline]
  32. Szilagyi DE, Elliott JP, Jr, Smith RF, Reddy DJ, McPharlin M. A thirty-year survey of the reconstructive surgical treatment of aortoiliac occlusive disease. J Vasc Surg 1986; 3:421-436.[CrossRef][Medline]
  33. Sicard GA, Freeman MB, VanderWoude JC, Anderson CB. Comparison between the transabdominal and retroperitoneal approach for reconstruction of the infrarenal abdominal aorta. J Vasc Surg 1987; 5:19-27.[CrossRef][Medline]
  34. Littooy FN, Steffan G, Steinam S, Saletta C, Greisler HP. An 11-year experience with aortofemoral bypass grafting. Cardiovasc Surg 1993; 1:232-238.[Medline]
  35. Passman MA, Taylor LM, Moneta GL, et al. Comparison of axillofemoral and aortofemoral bypass for aortoiliac occlusive disease. J Vasc Surg 1996; 23:263-271.[CrossRef][Medline]
  36. Kallero KS. Mortality and morbidity in patients with intermittent claudication as defined by venous occlusion plethysmography: a ten-year follow-up study. J Chronic Dis 1981; 34:455-462.[CrossRef][Medline]
  37. Coffman JD. Intermittent claudication: be conservative. N Engl J Med 1991; 325:577-578.[Medline]
  38. Fowl RJ, Gewirtz RJ, Love MC, Kempczinski RF. Natural history of claudicants with critical hemodynamic indices. Ann Vasc Surg 1992; 6:31-33.[CrossRef][Medline]
  39. Dormandy JA, Rutherford RB. Management of peripheral arterial disease (PAD): TASC Working Group—Transatlantic Inter-Society Consensus (TASC). J Vasc Surg 2000; 31:S1-S296.[CrossRef][Medline]
  40. Sullivan TM, Childs MB, Bacharach JM, Gray BH, Piedmonte MR. Percutaneous transluminal angioplasty and primary stenting of the iliac arteries in 288 patients. J Vasc Surg 1997; 25:829-839.[CrossRef][Medline]
  41. Lee ES, Steenson CC, Trimble KE, Caldwell MP, Kuskowski MA, Santilli SM. Comparing patency rates between external iliac and common iliac artery stents. J Vasc Surg 2000; 31:889-894.[CrossRef][Medline]
  42. Timaran CH, Stevens SL, Freeman MB, Goldman MH. External iliac and common iliac artery angioplasty and stenting in men and women. J Vasc Surg 2001; 34:440-446.[CrossRef][Medline]
  43. Johnston KW. Iliac arteries: reanalysis of results of balloon angioplasty. Radiology 1993; 186:207-212.[Abstract/Free Full Text]
  44. Friedman LM, Furberg CD, De Mets DL. Introduction to clinical trials: fundamentals of clinical trials 1998 New York, NY: Springer-Verlag, 1998; 1-15.



This article has been cited by other articles:


Home page
 PERSPECT VASC SURG ENDOVASC THERHome page
M. J. Sharafuddin, J. J. Hoballah, T. F. Kresowik, and W. J. Sharp
Kissing Stent Reconstruction of the Aortoiliac Bifurcation
Perspectives in Vascular Surgery and Endovascular Therapy, March 1, 2008; 20(1): 50 - 60.
[Abstract] [PDF]

Home page
 CirculationHome page
C. J. White and W. A. Gray
Endovascular Therapies for Peripheral Arterial Disease: An Evidence-Based Review
Circulation, November 6, 2007; 116(19): 2203 - 2215.
[Abstract] [Full Text] [PDF]

Home page
 RadiologyHome page
W. M. Klein, Y. v. d. Graaf, J. Seegers, J. H. Spithoven, E. Buskens, J. G. v. Baal, J. Buth, F. L. Moll, T. T. C. Overtoom, M. R. H. M. v. Sambeek, et al.
Dutch Iliac Stent Trial: Long-term Results in Patients Randomized for Primary or Selective Stent Placement
Radiology, December 21, 2005; (2005) 2382041053.
[Abstract] [Full Text]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
2311030408v1
231/1/243    most recent
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Murphy, T. P.
Right arrow Articles by Kim, H. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Murphy, T. P.
Right arrow Articles by Kim, H. M.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
RADIOLOGY RADIOGRAPHICS RSNA JOURNALS ONLINE