- This prospective study, PROMISE II, evaluated the LimFlow System in 105 patients with chronic limb-threatening ischemia who had no conventional surgical or endovascular revascularization options and were facing amputation as they were deemed "no-option"
- Transcatheter arterialization of the deep veins (TADV) was successfully performed in 104 patients (99%) and was associated with 66% amputation-free survival at six months, and 25% of patients had complete wound healing at six months
- Results were consistent among prespecified subgroups except that the patients with dialysis-dependent chronic kidney disease had amputation-free survival of 37% compared with 73% for the other patients
- The study was representative of real-world practice, as 74% of participants had a history of unsuccessful revascularization on the index limb, and all presented with a nonhealing ulcer or frank gangrene and were classified as Rutherford class 5 or 6 that would likely result in amputation
- For the "no-option" patient who is facing amputation because of lack of conventional revascularization techniques, especially diabetic or ESRD patients, TADV is a viable and safe option that can save the limb
The PROMISE I study established the feasibility of transcatheter arterialization of the deep veins, an endovascular revascularization procedure for patients with chronic limb-threatening ischemia with no conventional surgical or endovascular revascularization options and were facing amputation. Now, PROMISE II has shown that the procedure is safe and compares well with a prespecified performance goal.
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Anahita Dua, MD, MBA, MSc, co-director of the Peripheral Artery Disease Center at the Fireman Vascular Center at Massachusetts General Hospital, director of the Limb Evaluation and Amputation Prevention Program (LEAPP), director of the Vascular Lab (Waltham), associate director of the Wound Center, and director of clinical research, along with Mehdi H. Shishehbo, DO, MPH, PhD, president of the Harrington Heart and Vascular Institute at University Hospitals, and colleagues published the results in The New England Journal of Medicine.
PROMISE I and II used the LimFlow System (LimFlow, San Jose, CA, which sponsored the studies). In a lower limb, the procedure involves creating an arteriovenous fistula proximal to the diseased tibial arteries using a covered stent. The oxygenated blood is diverted from the tibial arteries to the tibial veins, bypassing the severely diseased arterial vasculature.
The venous system is leveraged to deliver oxygenated arterial blood to the foot through the pedal veins, to avert major amputation and promote wound healing.
PROMISE II was conducted across 20 U.S. sites between December 2019 and March 2022. Participants with chronic limb-threatening ischemia were screened with angiography and vein mapping, and an independent physician review committee confirmed a no-option status for 105 patients:
- Absence of a pedal artery target for endovascular or surgical therapy (97%)
- Absence of a viable single segment of an autogenous vein conduit despite the presence of a pedal artery target that could receive a graft (3%)
31% of participants were women, the median age was 70, and 43% were Black or Latino/a/x. Most participants had several preexisting conditions associated with chronic limb-threatening ischemia, including diabetes (77%), hypertension (91%), and/or dyslipidemia (70%).
The primary endpoint was amputation-free survival at six months, evaluated against a prespecified performance goal of 54%. The primary standard of study success was a posterior probability in Bayesian analysis exceeding 0.977.
At six months, 66% of participants had amputation-free survival. The posterior probability that the six-month amputation-free survival exceeded the performance goal of 54% was 0.993, greater than the prespecified success criterion.
In prespecified analyses, there were no clinically relevant differences between subgroups, except the 19 patients with dialysis-dependent chronic kidney disease had amputation-free survival of 37% compared with 73% for the 86 patients without dialysis-dependent chronic kidney disease.
Secondary outcomes included:
- Technical success of the procedure—99%
- Procedural success (technical success plus survival at 1 month with no major amputation or reintervention)—77%
- Limb salvage (avoidance of above-ankle amputation) at 6 months—76% of patients
- Survival at 6 months—87%
- Complete healing of target wound at 6 months—25%
- Partial healing of target wound at 6 months—51%
A Real-World Study
PROMISE II was representative of real-world practice, as it included types of patients routinely excluded from vascular device studies. 74% had a history of unsuccessful revascularization procedures on the index limb, and all presented with a nonhealing ulcer or frank gangrene and were classified as Rutherford class 5 or 6. This is a new option for patients who otherwise would be facing amputation.
Learn about the Limb Evaluation and Preservation Program
Refer a patient to the Fireman Vascular Center