ClinicalTrials.gg
Active, not recruitingNCT03807531DEEPER OUSUpdated Aug 12, 2026

A Study of the Temporary Spur Stent for the Treatment of Narrowing and Blockages in the Arteries Below the Knee

An interventional study of Temporary Spur Stent System in Peripheral Arterial Disease, sponsored by ReFlow Medical, Inc.. Active, not recruiting at 6 sites in 3 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-12.

Sponsored by ReFlow Medical, Inc. · Not applicable, Interventional, and Treatment

Phase
Not applicable
Study type
Interventional
Enrollment
100
Allocation
Not applicable
Ages
18 Years and older
Sex
All
01

Where this study stands

Counted across the records on this site · 2026-11-12

Among 173 studies in Peripheral Arterial Disease with a site in Germany — 15 open to participants now, 29 under way, 3 of them phase 3. Peripheral Arterial Disease · Germany.

Planned enrollment
66th of 126
100 · median 107
Started
2019
with 6 others
No phase
85 of 173
8 open now
Primary completion
2023-04
later than 2 of 28 live
Registered
117th of 173
by date

Among the 173 studies in Peripheral Arterial Disease with a site in Germany, this one is the 66th largest by planned enrollment of the 126 interventional ones, is one of 7 that started in 2019, is one of 85 with no phase, reaches primary completion later than 2 of the 28 other live ones, and was the 117th registered.

By phase

173 studies; the count open now beside each. This study's row is marked.

No phasethis study85 · 8 open
Observational47 · 5 open
Phase 314 · 1 open
Phase 210 · 0 open
Phase 2/35 · 1 open
Phase 45 · 0 open
Phase 14 · 0 open
Phase 1/23 · 0 open

By the year they started

First in 2001; this study’s year is marked. 7 started in 2019.

Size and results

Median enrollment 107 across the 126 interventional studies, 200 across the 47 observational. Of the 118 that completed or were terminated, 34 (29%) have results posted.

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Watch this landscapeDownload CSVWith an account: a weekly mail of what changed among 173 studies in Peripheral Arterial Disease with a site in Germany, or all of them as a file.
02

Study summary

The purpose of this study is to evaluate the performance and safety of the Temporary Spur Stent System (TSS). The TSS is intended for use in conjunction with a commercially available drug coated balloon in the infrapopliteal arteries for the treatment of de novo or restenotic lesions.

This study is a prospective, non-randomized, multicenter, single arm trial, with sites in New Zealand, Germany, and Switzerland.

At least two and no more than 10 sites are expected to participate, with 100 subjects enrolled (no more than 40 at a single site).

The study follow up will take place over a period of 365 days. A vessel recoil substudy will be included for a select group of subjects.

Read the detailed description

The purpose of this clinical study is to evaluate the performance and safety of the Temporary Spur Stent System (TSS) for subjects with infrapopliteal arterial disease.

The Temporary Spur Stent System is intended for use in conjunction with a commercially available drug coated balloon in the infrapopliteal arteries for the treatment of de novo or restenotic lesions.

The TSS has been developed to provide another treatment option for patients with Peripheral Arterial Disease (PAD), and Critical Limb Ischemia (CLI).

Up to 100 subjects will be treated with the Temporary Spur Stent System in conjunction with an approved Drug Coated Balloon (DCB). No less than 1 subject and no more than 40 subjects will be enrolled at a single site.

A vessel recoil substudy is included in the trial. The purpose of this study is to evaluate vessel recoil in a select group of subjects (no more than 10 per site, up to 35 subjects in total). This will be conducted by obtaining measurements using Optical Coherence Tomography (OCT), Intravascular Ultrasound (IVUS), or Quantitative Vascular Analysis (QVA) of the target vessel during the index procedure.

The statistical analysis for this trial will use as a comparator a performance goal derived from a meta-analysis of infrapopliteal balloon angioplasty. Descriptive statistics may be used to describe other data points.

Subjects will be asked to participate in a baseline evaluation visit, the index procedure, a 30 day follow up visit, a 90 day follow up visit, a 180 day follow up visit, and a 365 day follow up visit. The baseline evaluation and index procedure visits may be combined. At each follow up visit, the subject will undergo a physical exam with wound evaluation (if applicable) including pictures, a medication history and compliance review, Ankle Brachial and Toe Brachial Indices (ABI and TBI), a duplex ultrasound of the treated limb, review of symptoms, and Adverse Events (AE) assessment. Subjects may choose to withdraw from the study at any time, for any reason. If subjects choose to withdraw, they will be asked to undergo an unscheduled study visit consisting of the aforementioned procedures.

03

Conditions studied

  • Peripheral Arterial Disease
04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Subject is willing and able to provide and able to comply with the study protocol.
  2. >1 year in the investigator's opinion
  3. Subject is > 18 years of age.
  4. Subject is Rutherford class 3-5.
  5. Stenotic, restenotic, or occlusive lesions located in the infrapopliteal vessels, with target lesion that can be successfully crossed with a guidewire.
  6. Target lesion must meet lesion-specific criteria in pre-screening by angiography (pre-screening with CTA, MRA or selective angiography may be performed prior to the index procedure)
  7. Target vessel(s) reconstitutes(s) at or above the medial malleolus, with the target treated segment extending no more than 10 mm beyond the medial malleolus.

    Note: If the anterior tibial or posterior tibial arteries are treated, there must be inline flow to the foot.

    If the peroneal artery is treated, there must be at least one collateral supplying the foot.

  8. Target lesion must begin no higher than the tibioperoneal trifurcation (popliteal arteries excluded).
  9. Target vessel reference diameter is measured to be between 2.0 mm to 4.5 mm in diameter, assessed by one of the following methods after successful completion of guidewire crossing of the lesion site:

    1. Intravascular Ultrasound (IVUS)
    2. Optical Coherence Tomography (OCT)
    3. Quantitative Vascular Angiography (QVA).
  10. Lesion length must be > 30 mm and \< 150 mm.
  11. Only one limb may be enrolled per subject. Up to two vessels may be treated per subject; if required, a second modality may be used for treatment in the non-target infrapopliteal vessel. Any treatment of the non-index vessel must be performed prior to the use of the investigative device and only one artery may be treated with the investigative device
  12. The total treated segment is defined as the total length of artery treated with the device. Target treatment length is \<240 mm with a maximum segment of 150 mm separated by 30 mm of healthy tissue between treated lesions.
  13. Successful pre-dilatation of the target lesion as outlined in the procedure instructions, defined as resulting in stenosis \<50%, without resulting flow limiting dissection (Type D or greater), thrombus, or aneurysm by angiography prior to the insertion of the investigative device.
  14. Iliac, SFA and popliteal inflow lesions can be treated using standard angioplasty and/or an approved stent (no atherectomy) during the index procedure or >30 days prior. Inflow lesions treated intraprocedure must be treated first, prior to consideration of treatment of infrapopliteal lesions. If pre-screening with angiography, CTA, MRA, or ultrasound has been performed \<365 days prior to the procedure, intra-procedure angiography of the aorto-iliac vasculature is not required, however, the infrainguinal inflow must still be imaged using angiography during the index procedure. Inflow lesions must have a healthy vessel segment of >30 mm between the study lesion and the treated segment, defined as less than 50% stenosis without aneurysmal segments.
  15. Retrograde access (in the infrapopliteal arteries) is permitted for lesion crossing, however, the Temporary Spur Stent System must be deployed from antegrade access
  16. For subjects with bilateral disease, planned treatment of the contralateral limb must either be performed >30 days prior to the index procedure or > 14 days following the index procedure.

Exclusion criteria

Exclusion Criteria:

  1. Subject unwilling or unlikely to comply with the appropriate follow up time for the duration of the study in the opinion of the investigator.
  2. Subject is pregnant or planning to become pregnant during the course of the trial.
  3. Subject has an active infection that is not controlled at the time of the procedure, including septicemia or bacteremia.
  4. Subject has osteomyelitis or a heel wound.
  5. Planned major (above the ankle) amputation of the target limb. A planned or previous minor (transmetatarsal or digit amputation) is permitted
  6. Recent myocardial infarction or stroke \< 90 days prior to the index procedure.
  7. Heart failure with \< 35%
  8. Impaired renal function ( \<25 mL/min) within 30 days of procedure and subjects on dialysis
  9. Subject with vasculitis, systemic Lupus Erythematosus or Polymyalgia Rheumatica.
  10. Subject receiving chronic or intravenous therapy.
  11. Inability to tolerate dual antiplatelet and oral anticoagulation therapy.
  12. Known allergies or sensitivities to heparin, antiplatelet, or other anticoagulant therapies which could not be substituted, and/or paclitaxel or an allergy to contrast media that cannot be adequately pre-treated prior to the index procedure.
  13. The subject is currently enrolled in another device or drug trial that may interfere with the endpoints of this study.
  14. Known allergy to nitinol or nickel.
  15. Prior stent(s) within the target vessel, or bypass surgery of or within the target vessel(s)
  16. Target lesion is located within an aneurysm or associated with an aneurysm in the vessel segment either proximal or distal to the target lesion. Inflow must also be free of aneurysmal segments.
  17. Previous treatment failure of inflow arteries (Iliac, SFA and popliteal) which required a surgical procedure. Prior bypass above the level of the infrapopliteal arteries is permitted.
  18. Previous treatment of inflow lesions, if not treated during the index procedure, must have been performed >30 days prior to the index procedure.
  19. Previous treatment of the target vessel \<30 days prior to index procedure
  20. Angiographic evidence of thrombus within target limb.
  21. Inability to obtain antegrade access in the limb from which the investigative device can be deployed.
  22. Extremely severe calcification classified as grade 4 as measured by the Peripheral Academic Research Consortium (PARC) score or the Peripheral Arterial Calcium Scoring System (PACSS) that, in the investigator's opinion, would not be amenable to PTA.
  23. Type D dissections or greater incurred during pre-dilation or CTO crossing.
  24. Significant (>50%) stenosis of inflow arteries or unsuccessful treatment of inflow lesions.
Terms in these criteria, in plain language(6)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

Life expectancy

The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

LVEF (left ventricular ejection fraction)

The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.

GFR and eGFR (kidney filtering)

GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².

Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
100 participants (estimated)

Study arms

  • Other
    Treatment with TSS

    This is a single-arm study. Participating subjects will be treated with the Temporary Spur Stent System (TSS)

    Device: Temporary Spur Stent System

Interventions

  • DeviceTemporary Spur Stent System

    Participating subjects that meet inclusion and exclusion criteria will undergo treatment of infrapopliteal occlusions and stenoses with the Temporary Spur Stent System according to protocol guidelines

    Also known as: G2-SPUR04X60, G2-SPUR03X60, G2-SPUR02x60

06

What researchers measure

Primary outcomes

  1. Primary patency of treated lesion sites by duplex ultrasound in subjects who are free from clinically driven TLR (target lesion revascularization)

    The primary performance endpoint will be primary patency of treated lesion sites by duplex ultrasound in subjects who are free from clinically driven TLR (target lesion revascularization).

    Time frame: 6 months

  2. Freedom from device and procedure-related death through 30 days post-procedure

    The primary safety endpoint is freedom from device and procedure-related death through 30 days post-procedure

    Time frame: 30 days

Secondary outcomes

  1. Freedom from clinically driven target lesion revascularization through 6 months post procedure.

    The secondary efficacy endpoint is freedom from clinically driven target lesion revascularization through 6 months post procedure.

    Time frame: 6 months

  2. Decrease in Rutherford class score at 3, 6 and 12 months.

    The second secondary efficacy measurement is decrease in Rutherford class score at 3, 6 and 12 months. Rutherford score is a classification system for patients with peripheral vascular disease. Categories are numbered from 0 to 6, with 0 being asymptomatic, and 6 being major tissue loss, functional foot no longer salvageable. Higher values are therefore considered a worse outcome. Rutherford class zero: No symptoms; Rutherford class 1: Mild Claudication (minimal leg pain with ambulation) symptoms; Rutherford Class 2: Moderate Claudication (moderate leg pain with ambulation); Rutherford Class 3: Severe claudication (severe leg pain with ambulation); Rutherford Class 4: Ischemic Rest pain (leg pain at rest); Rutherford Class 5: Minor tissue loss (nonhealing ulcer, focal gangrene, diffuse pedal ischemia); Rutherford class 6: Major tissue loss (extending above the transmetatarsal TM level, functional foot no longer salvageable.

    Time frame: 3, 6, and 12 months

  3. Wound healing for subjects with Rutherford class 5 at 6 and 12 months, as assessed by the investigator using WIfI score and descriptive characteristics, including change in wound size measured by any decrease in wound surface area.

    The third secondary efficacy endpoint is wound healing for subjects with Rutherford class 5 at 6 and 12 months, as assessed by the investigator using WIfI score and descriptive characteristics, including change in wound size measured by any decrease in wound surface area. The WIfI classification scoring system is a grading system using a composite score of wound (W), ischemia (I), and foot infection (fi). These three different categories are graded from 0 to 3 with 0 being the best and 3 being the worst. The total score will be provided (clinical stage 1-5), which is used to estimate the risk for major amputation at one year. Patients with a score of 1 are considered low risk, and patients with a score of 5 are considered high risk (foot not salvageable). Therefore, higher values are considered a worse outcome. The composite score is calculated by adding up the score from each category.

    Time frame: 6 and 12 months

07

Study locations

6 sites
08

References and documents

Publications

  • Mills JL Sr, Conte MS, Armstrong DG, Pomposelli FB, Schanzer A, Sidawy AN, Andros G; Society for Vascular Surgery Lower Extremity Guidelines Committee. The Society for Vascular Surgery Lower Extremity Threatened Limb Classification System: risk stratification based on wound, ischemia, and foot infection (WIfI). J Vasc Surg. 2014 Jan;59(1):220-34.e1-2. doi: 10.1016/j.jvs.2013.08.003. Epub 2013 Oct 12. PubMed 24126108 ↗

Individual participant data

Plan to share: No

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Jul 2019 to primary completion in Apr 2023, 45 months.

Of 125 industry-sponsored interventional studies with no phase under Peripheral Arterial Disease, half reached primary completion within 28 months of starting (the median), counting those still running; a quarter within 14 and three quarters within 45. This study's 45 months is above that.

Counting every sponsor, half of 385 studies reached it within 31 months; a quarter within 17 and three quarters within 55.

How these figures are worked out, and which studies are left out of them.

Registered
Jan 11, 2019
First posted
Jan 17, 2019
StartActual
Jul 11, 2019
Primary completionActual
Apr 30, 2023
CompletionEst.
Jun 1, 2027
Last update
Aug 12, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Aug 12, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT03807531
Lead sponsor
ReFlow Medical, Inc.
Collaborators
ClinLogix. LLC
Responsible party
Sponsor
First posted
Jan 17, 2019
Start date
Jul 11, 2019
Primary completion
Apr 30, 2023
Completion
Jun 1, 2027 (estimated)
Last update
Aug 12, 2026

Study contacts

Andrew Holden, MBChB
principal investigator · Auckland Hospital

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is active, not recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.

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Discussion

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