One-year results from the PROMISE II US pivotal trial demonstrate the durability of outcomes of transcatheter arterialisation of the deep veins (TADV) using the LimFlow system (LimFlow) and that the procedure is safe and reproducible.
Daniel Clair (Vanderbilt University Medical Center, Nashville, USA) recently presented the new data for the first time at VIVA 2023 (30 October–2 November, Las Vegas, USA). He reported a limb-salvage rate of 69% at 12 months, among other key results, in patients who have chronic limb-threatening ischaemia (CLTI) with no suitable endovascular or surgical revascularisation options.
Clair, who served as co-principal investigator of the trial alongside Mehdi Shishehbor (University Hospitals Harrington Heart & Vascular Institute, Cleveland, USA), noted that the new data are an extension of the six-month PROMISE II results that were presented at VIVA 2022. Following publication of these results in the New England Journal of Medicine (NEJM), the US Food Administration (FDA) approved the LimFlow system in September of this year.
At 20 centres without roll-ins across the USA, 105 no-option CLTI patients were enrolled in a non-randomised manner. All enrolled patients had Rutherford class 5 or 6 disease and were deemed by an independent committee of experts to be ineligible for endovascular or surgical procedures to restore blood flow.
The median age of the patient cohort was 70 years, two-thirds were male, and one-quarter were Hispanic or Latino. Most patients presented with pre-existing comorbidities, including diabetes, hypertension, dyslipidaemia, and a history of intervention on the index limb. All patients presented with a non-healing ulcer or frank gangrene and were classified as either Rutherford class 5 or 6.
Clair revealed at VIVA that, at one year, limb salvage was maintained in 69% of patients. “You can see—and this has been noted before—a drop-off through the first three months, but those who were able to keep their limbs to that point usually did significantly well over time,” he commented.
In addition, the presenter shared that the average wound area was 0.2cm2 at 12 months. “You are talking about minimal wounds that these patients had when they did have remaining wounds,” he said. Clair also noted an average pain score (scale 0–10) of 1.4 at 12 months, representing a “significant reduction” from an average of 5.3 at enrolment. More than half of patients were classified as Rutherford class 0 at one year.
In addition, Clair reported pooled results from PROMISE I and PROMISE II. “The PROMISE I trial did not include dialysis patients and did not include COVID deaths, but other than that these two trials were very similar,” he remarked. In the pooled analysis, the presenter noted an overall survival rate of 85%, a limb-salvage rate of close to 75%, and a 63% rate of amputation for this population.
“In conclusion, the [US] FDA has approved this product with the six-month data that have been published in the [NEJM], and these 12-month data extend upon that and show that this is a durable, sustainable outcome,” Clair summarised. He added that the outcomes are consistent even with new users. “The procedure is reproducible and generalisable—most operators in PROMISE II had essentially no experience with this technique—and I continue to believe that as we gain experience with this, over time we will learn more and do better as we move forward.”
“I am very proud to be able to present this information and happy with where we are headed with this complex group of patients,” he said in closing.
