Chronic Limb Threatening IschemiaNCT07465627
Vessel Recoil in Specific CLTI Populations
An observational study of Chronic Limb Threatening Ischemia, run by Medical University of Graz at 1 site in Austria.
Trial summary
Chronic limb threatening ischemia (CLTI) represents the most advanced stage of peripheral arterial disease (PAD) and is characterized by ischemic rest pain, non-healing wounds, or ischemic gangrene. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Chronic Limb Threatening Ischemia
- What is being tested?
- Vessel recoil measurement 15 minutes post final treatment (angiographically)
- How many people
- 40 participants
- Where
- 1 siteAustria
- Study dates
- 1 Jul 2026to Sep 2028
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Patients with below-the knee (BTK) peripheral arterial disease (PAD) who are either with chronic kidney disease (CKD) requiring hemodialysis for at least 6 months (cohort 1) and/or diabetics (cohort 2) in Rutherford classes (RC) 4 or 5, with ≥ 50% females in each cohort
General Inclusion Criteria:
- Subject is willing and able to provide informed consent
- Subject is able to comply with the study protocol and with follow-up
- Life expectancy >1 year in the investigator's opinion
- Subject is > 18 years of age
- Subject must have symptoms of limb ischemia, determined by clinical symptoms of RC 4 or 5, including rest pain (RC 4) and/or minor tissue loss (RC 5), that in the opinion of the investigator are not amenable to conservative medical therapy and require endovascular intervention for alleviation of symptoms and tissue preservation
- Subject has stenotic, restenotic or occlusive lesions located in BTK vessels in pre-screening with CTA, MRA or angiography prior to the index procedure.
- Subject suffers from diabetes and/or receives chronic hemodialysis for KD (for at least 6 months)
- Diabetes cohort: Subject requires for estimated glomerular filtration rate (eGFR) ≥ 25ml/min (within 30 days of procedure)
- Hemodialysis cohort: Subject has been receiving hemodialysis treatment for ≥ 6 months. (Note: subjects with diabetes who also receive chronic hemodialysis will be excluded from the diabetes cohort and will be included only in the hemodialysis cohort).
Angiographic Inclusion Criteria:
- Target lesion can be successfully crossed with a guidewire.
- Target lesion must be located in BTK arteries. Treatment of the distal popliteal segment (P3) is permitted provided that sizing remains appropriate (no more than 4.5 mm in diameter).
- Target vessel reconstitutes at or above the medial ankle, with the target treated segment extending no more than 10 mm beyond the ankle.
- 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.
- Target vessel reference diameter is measured to be between 2.5 mm to 4.5 mm in diameter.
- Only one artery may be treated with the Spur device.
- Non-target infrapopliteal lesions requiring treatment must be treated prior to treatment of the target lesion. Treatment of the target vessel/lesion with the Spur device may be performed only if treatment of the non-target vessel(s)/lesion(s) does not result in a complication which may compromise the outflow of the target lesion or result in a major adverse limb event.
- The treated segment is defined as the total length of artery treated with the Spur device. Total target treatment length must be < 250mm with a maximum segment of 220 mm separated by 30 mm of healthy tissue between treated lesions.
- Successful pre-dilatation of the target lesion as outlined in the procedure instructions, defined as resulting in stenosis ≤ 50%, without resulting flow limiting (Type D or greater) dissection, thrombus, or aneurysm by angiography prior to the insertion of the Spur device.
- Iliac, SFA and popliteal inflow lesions can be treated during the index procedure. Inflow lesions treated intraprocedure must be treated first, prior to consideration of treatment of infrapopliteal lesions. Inflow lesions must have a healthy vessel segment of >30 mm between the study lesion and the treated segment, defined as ≤ 50% stenosis.
- The Spur must be deployed from antegrade access.
General Exclusion Criteria:
- Subject is unwilling or unlikely to comply with the duration of the study (up to 12 months +/-30 days post intervention) in the opinion of the investigator
- Subject is pregnant or planning to become pregnant during the course of the trial
- Subject is breastfeeding or planning to breastfeed during the course of the trial
- Subject has an active and uncontrolled systemic infection, including septicemia or bacteremia
- Subject has documented active osteomyelitis proximal to the phalanges of the target limb. Osteomyelitis in the digit(s) of the target foot is permitted.
- Subject has a wound above the ankle and/or a heel wound
- Subject has planned or had previous major (above the ankle) amputation of the target limb. A planned or previous minor (transmetatarsal amputation or digit amputation) is permitted.
- Subject with poor and insufficient general condition and/or comorbidities not allowing for endovascular treatment as per the investigator's discretion
- Diabetes cohort: subject has impaired renal function as defined by an eGFR < 25 mL/min within 30 days of procedure
- Hemodialysis cohort: subject has been receiving hemodialysis treatment for less than 6 months
- Subject with inability to comply with antiplatelet and/or anticoagulation therapy as per the facility's standard of care
- Subject with known allergies or sensitivities to heparin, antiplatelet drugs, other anticoagulant therapies which do not allow for an adequate peri- and post-procedural treatment
- Subject with known allergies or sensitivities to Paclitaxel or Sirolimus balloon coatings
- Subject with known allergies or sensitivities to contrast media that cannot be adequately pre-treated prior to the index procedure
- Subject with known allergies or sensitivities to nitinol or nickel
- Subject is currently enrolled in another investigational device or drug trial that interferes with the study endpoints.
- Subject with prior stent(s) within the target vessel, or bypass surgery of or within the target vessel
- Subject had previous treatment of the target vessel <30 days prior to index procedure
Angiographic exclusion criteria:
- Angiographic evidence of thrombus within target limb
- Inability to obtain antegrade access in the limb from which the Spur can be deployed
- Any lesion characteristics, that in the investigator's opinion, would not be amenable to endovascular standard techniques
- Significant > 50% stenosis of inflow arteries or unsuccessful treatment of inflow lesions
- > 50% stenosis, flow-limiting dissection (Type D or greater), aneurysm or thrombus of the target lesion following pre-dilation
- Inability to obtain additional imaging 15 minutes after target lesion treatment for recoil evaluation.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Austria1 site, 1 recruiting
- Recruiting
Medical University of Graz, Division of Angiology
Graz
Katharina Kurzmann-Guetl, +43 316 385 12911, katharina.guetl@medunigraz.at
About this study
Official title: Early Vessel Recoil Following Below-the-knee (BTK) Artery Treatment With the Spur Peripheral Retrievable Scaffold System in Specific Patient Populations With Chronic Limb-threatening Ischemia (CLTI) - The DEEPER CHALLENGE Single Center Prospective Study
Chronic limb threatening ischemia (CLTI) represents the most advanced stage of peripheral arterial disease (PAD) and is characterized by ischemic rest pain, non-healing wounds, or ischemic gangrene. High-risk PAD populations including patients with end-stage renal disease and or diabetes also experience worse outcomes with significantly increased rates of amputation and mortality.
Although some patients with PAD are best treated with a combination of medical management, exercise and lifestyle modification, revascularization is indicated in those with advanced stages of disease and particularly in the presence of CLTI. Revascularization of below-the-knee (BTK) arteries is required for most patients suffering from CLTI, but treatment faces numerous challenges comprising calcification, small vessel size, long-lesion length and early elastic recoil. With regard to these challenges, numerous innovative techniques and devices have been developed within the past decades to optimize endovascular treatment of BTK vessels.
Read more
The Spur Peripheral Retrievable Scaffold System (Spur) was developed to directly address many of these pitfalls of infrapopliteal arterial disease. The premise of the design of the Spur is to provide temporary mechanical scaffolding and to prepare the vessel for treatment with a drug-coated balloon (DCB) to enhance drug absorption by creating channels in the endothelium by the deployed Spur.
The objective of this study is to perform a prospective, single-center, single-arm, non-randomized study to evaluate acute vessel recoil following BTK treatment with the Spur Retrievable Scaffold System in combination with a commercially available DCB in specific patients populations. Specific patient populations that are selected to participate in this study are either at high risk to discover unfavorable outcomes with standard techniques due to a high complexity of lesions and/or patients that are not adequately mirrored in available studies. The patient cohorts that will be studied are diabetics and patients on hemodialysis (for at least 6 months). As women are commonly under-represented in comparable trials, this study requires at least 50% of women for each cohort.
The primary endpoint is vessel recoil within 15 minutes post treatment assessed with angiography. Secondary endpoints will be followed out to 12 months.
- Conditions
- Chronic Limb Threatening Ischemia
- Being tested
- Vessel recoil measurement 15 minutes post final treatment (angiographically)
- Keywords
- vessel recoil, peripheral arterial disease, endovascular revascularization, below-the-knee, chronic limb-threatening ischemia
- Medical subject headings
- Chronic Limb-Threatening Ischemia, Peripheral Arterial Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Vessel recoil measurement 15 minutes post final treatment (angiographically)Other
This study will evaluate early recoil following optimized endovascular treatment (Spur Peripheral Retrievable Scaffold System in combination with a DCB) of BTK vessels in specific high-risk patient populations with CLTI.
| Study group | Role | What they receive |
|---|---|---|
| CLTI patients on chronic hemodialysis | Not described Receives: Other: Vessel recoil measurement 15 minutes post final treatment (angiographically) | |
| CLTI patients with diabetes | Not described Receives: Other: Vessel recoil measurement 15 minutes post final treatment (angiographically) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Vessel recoil assessed with angiography
Measured: 15 minutes post treatment
Secondary outcomes (8)
Freedom from unplanned major (above the ankle) amputation
Measured: Up to 12 months
Freedom from major adverse limb events (MALE)
Measured: Up to 12 months
Freedom from all-cause mortality
Measured: Up to 12 months
Freedom from clinically driven target lesion revascularisation (CD-TLR)
Measured: Up to 12 months
Target vessel patency determined by duplex ultrasound (DUS)
Measured: 30 days
Change in ankle brachial index (ABI, or toe brachial index (TBI) alternatively) from baseline
Measured: 30 days
Change in Rutherford Class from baseline
The Rutherford Class (RC) ranges from 0 to 6, with a higher class indicating more severe disease.
Measured: 30 days
Change in Wound, Ischemic, and foot Infection score (WIfI) from baseline
The WIfI score ranges from 0 to 9, with a higher point score indicating more severe disease.
Measured: 30 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Mar 2026
- Study start1 Jul 2026
- Primary completionJun 2027 (estimated)
- Study completionSep 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Chronic Limb Threatening IschemiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Medical University of Graz
- Sponsor type
- University, hospital or other
- Collaborators
- ReFlow Medical, Inc.
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07465627
- Sponsor's protocol ID
- 1469/2025
- Status last verified
- Jun 2026
- First submitted
- 6 Mar 2026
- Last updated
- 14 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 14 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Early Vessel Recoil Following Below-the-knee (BTK) Artery Treatment With the Spur Peripheral Retrievable Scaffold System in Specific Patient Populations With Chronic Limb-threatening Ischemia (CLTI) - The DEEPER CHALLENGE Single Center Prospective Study
- ClinicalTrials.gov ID
- NCT07465627
- Acronym / sponsor ID
- 1469/2025
- Conditions
- Chronic Limb Threatening Ischemia
- Keywords
- vessel recoil, peripheral arterial disease, endovascular revascularization, below-the-knee, chronic limb-threatening ischemia
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Medical University of GrazUniversity, hospital or other
- Collaborators
- ReFlow Medical, Inc.
- Study start
- 1 Jul 2026 (actual)
- Primary completion
- Jun 2027 (estimated)
- Study completion
- Sep 2028 (estimated)
- First posted
- 12 Mar 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Chronic limb threatening ischemia (CLTI) represents the most advanced stage of peripheral arterial disease (PAD) and is characterized by ischemic rest pain, non-healing wounds, or ischemic gangrene. High-risk PAD populations including patients with end-stage renal disease and or diabetes also experience worse outcomes with significantly increased rates of amputation and mortality.
Although some patients with PAD are best treated with a combination of medical management, exercise and lifestyle modification, revascularization is indicated in those with advanced stages of disease and particularly in the presence of CLTI. Revascularization of below-the-knee (BTK) arteries is required for most patients suffering from CLTI, but treatment faces numerous challenges comprising calcification, small vessel size, long-lesion length and early elastic recoil. With regard to these challenges, numerous innovative techniques and devices have been developed within the past decades to optimize endovascular treatment of BTK vessels.
The Spur Peripheral Retrievable Scaffold System (Spur) was developed to directly address many of these pitfalls of infrapopliteal arterial disease. The premise of the design of the Spur is to provide temporary mechanical scaffolding and to prepare the vessel for treatment with a drug-coated balloon (DCB) to enhance drug absorption by creating channels in the endothelium by the deployed Spur.
The objective of this study is to perform a prospective, single-center, single-arm, non-randomized study to evaluate acute vessel recoil following BTK treatment with the Spur Retrievable Scaffold System in combination with a commercially available DCB in specific patients populations. Specific patient populations that are selected to participate in this study are either at high risk to discover unfavorable outcomes with standard techniques due to a high complexity of lesions and/or patients that are not adequately mirrored in available studies. The patient cohorts that will be studied are diabetics and patients on hemodialysis (for at least 6 months). As women are commonly under-represented in comparable trials, this study requires at least 50% of women for each cohort.
The primary endpoint is vessel recoil within 15 minutes post treatment assessed with angiography. Secondary endpoints will be followed out to 12 months.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| CLTI patients on chronic hemodialysis | – | Other: Vessel recoil measurement 15 minutes post final treatment (angiographically) |
| CLTI patients with diabetes | – | Other: Vessel recoil measurement 15 minutes post final treatment (angiographically) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Patients with below-the knee (BTK) peripheral arterial disease (PAD) who are either with chronic kidney disease (CKD) requiring hemodialysis for at least 6 months (cohort 1) and/or diabetics (cohort 2) in Rutherford classes (RC) 4 or 5, with ≥ 50% females in each cohort
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Vessel recoil measurement 15 minutes post final treatment (angiographically)This study will evaluate early recoil following optimized endovascular treatment (Spur Peripheral Retrievable Scaffold System in combination with a DCB) of BTK vessels in specific high-risk patient populations with CLTI. | Other | CLTI patients on chronic hemodialysis, CLTI patients with diabetes |
Primary outcome
Vessel recoil assessed with angiography
Time frame: 15 minutes post treatment
8 secondary outcomes
Freedom from unplanned major (above the ankle) amputation
Time frame: Up to 12 months
Freedom from major adverse limb events (MALE)
Time frame: Up to 12 months
Freedom from all-cause mortality
Time frame: Up to 12 months
Freedom from clinically driven target lesion revascularisation (CD-TLR)
Time frame: Up to 12 months
Target vessel patency determined by duplex ultrasound (DUS)
Time frame: 30 days
Change in ankle brachial index (ABI, or toe brachial index (TBI) alternatively) from baseline
Time frame: 30 days
Change in Rutherford Class from baseline
Time frame: 30 days
Change in Wound, Ischemic, and foot Infection score (WIfI) from baseline
Time frame: 30 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Oct 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Medical University of Graz, Division of Angiology
Graz, Austria
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Chronic Limb Threatening Ischemia, run by Medical University of Graz at 1 site in Austria.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 14 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Austria. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Each site lists its own contact: choose the nearest one under Trial locations. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Vessel recoil assessed with angiography (time frame: 15 minutes post treatment). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Oct 2026.