The United States StuDy for EvalUating
EndovasculaR TreAtments of Lesions in the
Superficial Femoral Artery and Proximal Popliteal
By usIng the Protégé EverfLex NitInol STent
SYstem II (DURABILITY II)
Jon S. Matsumura, MD,aDai Yamanouchi, MD, PhD,aJeffrey A. Goldstein, MD,b
Christopher W. Pollock, MD,cMarc Bosiers, MD,dGreg A. Schultz, MD,eDierk Scheinert, MD,fand
Krishna J. Rocha-Singh, MD,gMadison, Wisc; Springfield, Ill; Knoxville, Tenn; Dendemonde, Belgium;
Sioux Falls, SDak; and Leipzig, Germany
Objective: Angioplasty and stenting are options for revascularization of symptomatic femoral popliteal disease. Although
angioplasty alone is effective in short lesions, longer lesions are often treated with stents. Multiple overlapping stents are
expensive and may be associated with stent fracture. This trial evaluated the safety and efficacy of a single self-expanding
stent up to 20 cm in length in patients with atherosclerotic disease of the superficial femoral artery (SFA) and proximal
Methods: Patients with lesions >4 cm and <18 cm were enrolled in this nonrandomized, prospective, multicenter trial that
evaluated the Protégé EverFlex Self-Expanding Peripheral Stent System (Covidien, Plymouth, Minn). The study’s
primary end points were the 30-day major adverse event rate and duplex ultrasound-assessed patency at 1 year. These
were compared with published performance goals. A preplanned analysis was conducted for the primary effectiveness end
points at 1 year. Follow-up, including history, ankle-brachial index, patient-reported outcomes, duplex ultrasound
assessment, and radiographs, is planned through 3 years. There was core laboratory review of angiograms, ultrasound
scans, and plain radiographs. A subgroup of patients was studied with graded treadmill testing.
Results: The study enrolled 287 patients (66% male; mean age, 68 years) with stenotic, restenotic, or occluded lesions of
the SFA at 44 investigational sites in the United States and Europe. Systemic comorbidities included hypertension (88%),
hyperlipidemia (86%), diabetes (43%), and prior SFA intervention (41%). The mean lesion length measured by the core
laboratory was 89 mm. The mean normal-to-normal lesion length measured by sites was 110 mm. A total of 303 stents
were implanted, and 95% of patients received a single stent. No major adverse events occurred at 30 days. At 1 year,
primary outcome of duplex ultrasound stent patency was 67.7% in evaluable patients, and among 1-year secondary
outcomes, the mean ankle-brachial index increased by 0.25. Walking Improvement Questionnaire scores improved in pain
by 33.7, distance by 37.1, speed by 18.6, and stair climbing by 24.7. The Kaplan-Meier estimate of primary patency was
77.2%, primary assisted patency was 86.9%, and secondary patency was 87.3%. Rutherford clinical category improved in
83.5% of patients. Stent fracture rate was 0.4%. Matched absolute claudication distance was 412 feet greater and was not
statistically different in this subgroup of 29 individuals.
Conclusions: The results of DURABILITY II (StuDy for EvalUating EndovasculaR TreAtments of Lesions in the
Superficial Femoral Artery and Proximal Popliteal By usIng the Protégé EverfLex NitInol Stent SYstem II) suggest that
a new single stent strategy is safe and effective for the treatment of long lesions of the SFA and proximal popliteal arteries
at 1 year. (J Vasc Surg 2013;58:73-83.)
Endovascular treatment is commonly performed as
an initial treatment of choice for peripheral arterial
disease (PAD), but optimal choices among various treat-
ment options continue to be debated. The second Trans-
Atlantic Inter-Society Consensus (TASC II) document
recommended endovascular treatment, including percuta-
neous transluminal angioplasty (PTA), stents and stent
grafts, and plaque excision, as the first choice for revascular-
ization of a variety of peripheral lesions, although endovas-
cular intervention is not recommended in long (>200 mm)
From the University of Wisconsin School of Medicine and Public Health,
Madisona; Prairie Cardiovascular Consultants, Springfieldb; Parkwest
Medical Center, Knoxvillec; AZ St-Blasius, Dendemonded; Sanford
University of South Dakota Medical School, Sioux Fallse; Park Hospital
and Heart Center, Leipzigf; and Prairie Vascular Institute, St John’s
Author conflict of interest: Drs Matsumura and Bosiers received
research grants from Covidien. Dr Rocha-Singh is a consultant to
Clinicaltrials.gov reference number: NCT00530712.
Additional material for this article may be found online at www.jvascsurg.org.
Reprint requests: Jon S. Matsumura, MD, UWSMPH, Division of Vascular
Surgery, G5/325 Clinical Science Center, 600 Highland Ave, Madison,
WI 53792 (e-mail: email@example.com).
The editors and reviewers of this article have no relevant financial relationships
to disclose per the JVS policy that requires reviewers to decline review of any
manuscript for which they may have a conflict of interest.
Copyright ? 2013 by the Society for Vascular Surgery.
occlusions.1In particular, treatment with PTA has been
associated with favorable outcomes in short lesions, partic-
ularly those <40 mm in length, but longer lesions have
demonstrated poorer results after PTA.2-9
Nitinol stent implantation after balloon angioplasty is
commonly used to treat the problems of early elastic recoil,
residual stenosis, and flow-limiting dissection and has been
used for the treatment of longer and more complex lesions
than in lesions treated with PTA alone. Initial randomized
controlled trials reported from 1997 to 2003 failed to show
benefit of a balloon-expandable stainless-steel stent over
expanding nitinol stents have shown better outcomes of
primary stenting than with PTA alone, with primary
patency rates as high as 81% at 1 year.7,8,10
The purpose of DURABILITY II (StuDy for EvalU-
ating EndovasculaR TreAtments of Lesions in the Superfi-
cial Femoral Artery and Proximal Popliteal By usIng the
Protégé EverfLex NitInol Stent SYstem II) was to evaluate
the safety and effectiveness of primary stenting using the
Protégé EverFlex Self-Expanding Peripheral Stent System
(Covidien, Plymouth, Minn; Fig 1) in the superficial
femoral artery (SFA) and proximal popliteal artery in
patients with symptomatic PAD. It was hypothesized that
a single, longer stent would support treatment of longer
lesions, leading to favorable patency results with a low
rate of stent fracture.
This study was conducted under an investigational
device exemption using a protocol approved by the U.S.
Food and Drug Administration (FDA).
Study design. DURABILITY II is a prospective,
multicenter, single-arm study to evaluate PTA and
primary stenting using a single self-expanding nitinol stent
compared with PTA alone in the treatment of atheroscle-
rotic SFA lesions, including long lesions up to 180 mm, in
symptomatic patients. The outcomes were compared with
performance goals modified from those developed by
VIVA (Vascular InterVentional Advances) Physicians Inc
(VPI) and promulgated in cooperation with the FDA. The
VPI performance goals were based on data from five
published randomized trials and three industry PTA trials,
and according to the agreement with the FDA, they
provide a basis for evaluation of stenting outcomes in
single-arm trials that require a demonstration of benefit
exceeding that obtained with PTA alone based on historic
data.11,12DURABILITY II is the first trial to use these
guidelines in its study design.
Inclusion and exclusion criteria are listed in Table I.
Before patient enrollment, each investigational site was
required to obtain Institutional Review Board approval,
and signed informed consent was required of all patients.
The study included independent oversight of safety,
including adverse events, as well as independent evaluation
of study outcomes. A Clinical Events Committee (CEC)
composed of independent physicians adjudicated adverse
events, and a Data Safety Monitoring Board (DSMB),
which included a biostatistician and independent physi-
cians, reviewed study data and monitored safety. Angio-
graphic, radiographic, and
laboratories analyzed all procedural and follow-up images.
In general, data are reported as adjudicated by the core
laboratories except for lesion length, for which both core
laboratory and site data are shown. The clinical sites used
measuring from healthy tissue to healthy tissue, whereas
the angiographic core laboratory measured “20-to-20”
lesion length, between the proximal and distal points at
which the lesion was 20% stenosed. These two methods
represent standard practice by the clinical sites and the
core laboratory, respectively, and have been similarly re-
Patient assessment. Medical history was obtained
before the procedure, including concomitant medication
use, Rutherford clinical category, rest ankle-brachial index
(ABI), the Walking Impairment Questionnaire (WIQ), and
laboratory results for serum creatinine and white blood cell
count. ABI, WIQ scores, and medications were also
recorded at the 30-day, 1-year, 2-year, and 3-year follow-
up visits, along with duplex ultrasound assessments. Angi-
ography was performed during the index procedure, and
the Rutherford clinical category was reassessed at 30 days
and at 1 year.
Adverse event evaluation was performed at the end of
the index procedure and at each follow-up visit. X-ray
imaging for evaluation of stent fractures was performed at
1, 2, and 3 years. In early versions of the study protocol,
absolute claudication distance by graded treadmill test
was required before the procedure and at 1 year; however,
this requirement was removed in a subsequent protocol
revision because of difficulties with recruitment and
compliance. Follow-up to 3 years was planned to permit
assessment of intermediate-term patency and stent fracture
rates, which will be reported when follow-up is completed.
duplex ultrasound core
Fig 1. A, Protégé EverFlex Self-Expanding Peripheral Stent cut in
an open lattice design showing spiral cell connectors, three-wave
peaks, peak-to-peak connection nodes, and tantalum markers at
the proximal and distal ends of the stent; available in stent lengths
of 20, 30, 40, 60, 80, 100, 120, 150, and 200 mm. B, A 200-mm
stent is depicted.
JOURNAL OF VASCULAR SURGERY
74 Matsumura et al
could be related to the longer stent, which reduces the use
of multiple stents with overlap zones that may be at higher
risk for fracture; as previously noted, only 5% of DURA-
BILITY II patients were implanted with multiple stents
at the index procedure, whereas in RESILIENT, with
a 12-month stent fracture rate of 3.1%, 50% of participants
received multiple stents. In the Zilver PTX (Cook Medical,
Bloomington, Ind) investigation, with a 12-month stent
fracture rate of 0.9%, a mean of 1.5 stents per patient
This study has several limitations. It was industry-
sponsored and not randomized, although it demonstrated
superiority to predefined performance goals derived from
PTA historic controls. There were few paired treadmill
patients, and the subset analysis of this functional clinical
outcome of claudication improvement is limited. Only
1-year results are reported, although follow-up is continu-
ing through 3 years; longer follow-up is needed to assess
interventions and fracture rates for these difficult, long,
with a patency of 67.7% using data collected in-window and
77.2% using all data by Kaplan-Meier estimate. Long lesions
according to core laboratory adjudication. There were no
30-day MAEs, and the stent fracture rate was 0.4% at 1
year. Objective measures of patency (duplex ultrasound
assessment and ABI) and patient-reported outcomes (WIQ
and Rutherford class) improved at 1 year compared with
baseline. Taken together, these data suggest that longer
stents, specifically designed for the SFA, provide an impor-
tant new single-stent treatment option.
The authors thank Julie Messer and Azah Tabah for
study coordination and data oversight and Mei Jiang and
Scott Brown for statistical analysis.
Conception and design: JM, KR
Analysis and interpretation: JM, KR, DY
Data collection: JG, CP, GS, MB, DS
Writing the article: JM, DY
Critical revision of the article: JM, KR, DY, JG, CP, GS,
Final approval of the article: JM, KR, DY, JG, CP, GS, MB,
Statistical analysis: JM, KR, DY
Obtained funding: JM, KR
Overall responsibility: JM
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Submitted Jul 25, 2012; accepted Dec 20, 2012.
Additional material for this article may be found online
JOURNAL OF VASCULAR SURGERY
Volume 58, Number 1
Matsumura et al 83
APPENDIX (online only)
Definitions of key clinical outcomes
Diabetes (history of). Defined as patients who have
been diagnosed with type 1 or type 2 diabetes and are
currently taking oral hypoglycemics or insulin.
Hypertension. Increase in systolic blood pressure
>140 mm Hg or a diastolic blood pressure >90 mm Hg.
Renal insufficiency. A 30% increase in serum creati-
nine from baseline.
Stroke. A neurologic deficit lasting >24 hours or
lasting #24 hours with a brain imaging study showing
Transient ischemic attack (TIA). A neurologic deficit
lasting <24 hours and, if an imaging study is performed,
shows no evidence of infarction.
Myocardial infarction (MI). Per the European
Society of Cardiology (ESC)/the American College of
Cardiology (ACC) definition.
JOURNAL OF VASCULAR SURGERY
83.e1 Matsumura et al