Medical University of Graz Enrolls First Patient in DEEPER CHALLENGE Trial Evaluating Early Vessel Recoil in High-Risk CLTI Patients
Reflow Medical, Inc. has announced the enrollment of the first participant in the DEEPER CHALLENGE clinical trial, marking an important milestone in research focused on improving treatment strategies for patients with chronic limb-threatening ischemia (CLTI). The investigator-initiated study, conducted at the Medical University of Graz, is designed to evaluate early vessel recoil following below-the-knee endovascular interventions using the Spur® Peripheral Retrievable Scaffold System in combination with a commercially available drug-coated balloon.
The first patient enrollment officially launches a prospective clinical investigation aimed at generating new insights into one of the persistent challenges in peripheral artery disease treatment. By focusing on the immediate mechanical response of blood vessels after intervention, researchers hope to better understand how vessel recoil influences long-term treatment success, particularly in patient populations that are considered among the most difficult to treat.
The DEEPER CHALLENGE trial is a single-center, single-arm, prospective study supported through a research grant. Unlike large randomized studies that compare multiple therapies, this investigator-driven research is specifically designed to collect detailed clinical and imaging data regarding vessel behavior immediately after treatment. The findings could help physicians optimize treatment approaches for below-the-knee arterial disease, particularly among patients who experience disproportionately high rates of restenosis and disease progression.
Addressing a Critical Challenge in Chronic Limb-Threatening Ischemia
Chronic limb-threatening ischemia represents the most advanced stage of peripheral artery disease (PAD), a condition characterized by reduced blood flow to the extremities due to narrowed or blocked arteries. Patients with CLTI frequently suffer from severe pain, non-healing ulcers, tissue loss, and significantly increased risks of amputation if blood flow cannot be successfully restored.
Treating below-the-knee arterial disease remains one of the most technically demanding areas in vascular intervention. The arteries below the knee are generally smaller in diameter, more heavily calcified, and frequently exhibit complex lesion patterns that make durable treatment outcomes difficult to achieve.
Although advances in balloon angioplasty, drug-coated technologies, atherectomy, and scaffolding devices have improved treatment options, restenosis—the re-narrowing of treated blood vessels—continues to be a major obstacle. One important contributor to restenosis is vessel recoil, where the artery partially returns toward its narrowed state shortly after angioplasty despite successful initial expansion.
Understanding how and when this recoil occurs may provide valuable information that helps physicians select appropriate treatment strategies capable of maintaining vessel patency over time.
Evaluating the Spur® Peripheral Retrievable Scaffold System
The DEEPER CHALLENGE study will evaluate procedures utilizing the Spur® Peripheral Retrievable Scaffold System together with a commercially available drug-coated balloon.
The Spur System is designed to temporarily provide mechanical scaffolding during endovascular intervention without leaving a permanent implant inside the vessel. By offering temporary structural support during balloon inflation and then being removed after treatment, the system seeks to improve vessel expansion while avoiding some of the long-term concerns associated with permanent metallic implants.
Combining temporary scaffolding with drug-coated balloon therapy may offer an attractive approach for physicians treating challenging below-the-knee lesions. Drug-coated balloons deliver antiproliferative medication directly to the vessel wall during angioplasty to reduce excessive tissue growth that can contribute to restenosis.
Researchers hope that studying the interaction between temporary mechanical support and drug delivery will provide important insights into optimizing vessel preparation and improving procedural outcomes.
Focus on Two Particularly High-Risk Patient Groups
One distinguishing feature of the DEEPER CHALLENGE trial is its deliberate focus on patient populations that have historically been underrepresented in clinical research despite experiencing some of the poorest clinical outcomes.
The study plans to enroll up to 40 patients diagnosed with chronic limb-threatening ischemia across two carefully defined cohorts.
The first cohort will consist of patients living with diabetes mellitus, a condition that significantly increases the likelihood of peripheral artery disease while also complicating wound healing and increasing amputation risk.
The second cohort will include patients with end-stage renal disease who have been receiving maintenance hemodialysis for at least six months. Individuals requiring dialysis frequently develop severe vascular calcification and complex arterial disease, making successful endovascular treatment considerably more challenging than in the general population.
By specifically studying these groups, investigators hope to generate evidence that more accurately reflects the clinical realities encountered by vascular specialists treating advanced peripheral artery disease.
Commitment to Greater Female Representation
Another notable aspect of the trial design is its emphasis on improving female representation in vascular clinical research.
Women have historically been underrepresented in many cardiovascular and peripheral vascular studies, limiting the availability of sex-specific data regarding procedural outcomes and treatment effectiveness.
To address this imbalance, investigators have designed the DEEPER CHALLENGE study so that women comprise at least 50 percent of each patient cohort.
This balanced enrollment strategy is intended to ensure that the resulting data better reflects the broader patient population affected by chronic limb-threatening ischemia while potentially identifying differences in vascular response between male and female patients.
Increasing diversity within clinical trials has become an increasingly important objective throughout medical research, as more representative study populations help generate evidence that can be applied more confidently in everyday clinical practice.
Measuring Early Vessel Recoil
The primary endpoint of the DEEPER CHALLENGE trial focuses on quantifying early vessel recoil following intervention.
Investigators will assess vessel recoil using angiographic imaging performed within 15 minutes after completion of treatment. This short observation window allows researchers to evaluate the immediate mechanical behavior of treated arteries before longer-term biological healing processes begin.
Early recoil is believed to influence procedural success and may contribute to later restenosis if the vessel loses a significant portion of its initial luminal gain soon after angioplasty.
Carefully measuring this phenomenon could improve understanding of how various treatment strategies affect immediate vessel stability and identify opportunities to optimize procedural techniques.
Comprehensive Secondary Clinical Endpoints
In addition to evaluating immediate mechanical vessel behavior, the study will collect a broad range of clinical outcomes throughout patient follow-up.
Secondary endpoints include the occurrence of major adverse limb events, overall mortality, and the need for repeat interventions over a 12-month period.
Researchers will also evaluate hemodynamic outcomes during the first 30 days after treatment to better understand how procedural success translates into improved blood flow.
Collecting both mechanical and clinical outcome data allows investigators to examine potential relationships between early vessel recoil and longer-term patient outcomes, including limb preservation and freedom from repeat procedures.
Investigators Highlight the Study’s Importance
Dr. Katharina Kurzmann-Gütl, Principal Investigator at the Medical University of Graz, emphasized that the study addresses an important knowledge gap regarding below-the-knee interventions.
According to Dr. Kurzmann-Gütl, the trial seeks to improve understanding of early vessel recoil in some of the most challenging patient populations undergoing endovascular therapy. By focusing on selective high-risk cohorts while ensuring balanced representation of female patients, the research is expected to generate findings that more accurately reflect the complexity of treating advanced peripheral artery disease in routine clinical practice.
She noted that the data generated may contribute to a deeper understanding of the immediate mechanical response of blood vessels following intervention and potentially inform future treatment strategies.
Addressing Longstanding Gaps in Clinical Evidence
Professor Marianne Brodmann, Co-Investigator and Head of the Division of Angiology at the Medical University of Graz, highlighted the significance of studying patient groups that are often overlooked in clinical trials.
She explained that patients with diabetes and individuals suffering from end-stage kidney disease face particularly high risks of restenosis and limb-threatening ischemia, yet they have historically been underrepresented in many clinical investigations evaluating treatments for chronic limb-threatening ischemia.
Professor Brodmann also pointed to the longstanding underrepresentation of women in medical research. By intentionally designing the study to include equal female participation within both cohorts, investigators hope to improve the generalizability of the findings.
She added that concentrating specifically on early vessel recoil will provide valuable information regarding the vessel’s immediate mechanical response after endovascular therapy, an area that remains incompletely understood despite continued advances in treatment technology.
Reflow Medical Supports Physician-Led Research
Reflow Medical views the DEEPER CHALLENGE trial as an example of its ongoing commitment to physician-driven clinical research aimed at improving outcomes for patients with complex peripheral artery disease.
Dejan Ilic, Vice President of Global Marketing at Reflow Medical, expressed enthusiasm about supporting the investigator-initiated study led by the Medical University of Graz.
He noted that the research addresses clinically important questions surrounding below-the-knee disease while reinforcing the company’s collaborative approach to advancing evidence-based treatment strategies.
According to Ilic, partnerships between medical technology developers and experienced physician investigators play an important role in generating clinically meaningful evidence that can ultimately guide patient care in high-risk populations.
As patient enrollment continues, the DEEPER CHALLENGE study is expected to provide important data regarding the immediate mechanical performance of below-the-knee interventions utilizing the Spur® Peripheral Retrievable Scaffold System alongside drug-coated balloon therapy.
The findings could enhance understanding of vessel recoil, inform future procedural techniques, and contribute to the development of more effective treatment strategies for patients with chronic limb-threatening ischemia. By concentrating on individuals with diabetes, patients undergoing long-term hemodialysis, and ensuring balanced female participation, the study aims to address significant evidence gaps while generating clinically relevant insights for physicians managing some of the most challenging cases in peripheral vascular medicine.
With the successful enrollment of its first participant, the DEEPER CHALLENGE trial has officially begun a research effort that may help shape future approaches to below-the-knee endovascular therapy and improve outcomes for patients facing the highest risks of limb loss and recurrent vascular disease.
About Reflow Medical, Inc.
Reflow Medical is a global company that partners with leading physicians to develop innovative technologies addressing unmet clinical needs in the endovascular treatment of complex cardiovascular disease. The company’s portfolio includes coronary and peripheral microcatheters, crossing catheters, and its proprietary Retrievable Scaffold Therapy (RST) platform. The Cora Catheters™ line is FDA approved. The peripheral product line includes Wingman™, Spex ® , Spex LP, and Spur ® , which have FDA clearance and CE Mark registration. Reflow Medical is headquartered in San Clemente, California.