(Leipzig, Germany) January 29, 2020 -- Two-year registry data on the LimFlow (LimFlow SA, France) percutaneous deep vein arterialization (pDVA) system were presented by Andrej Schmidt, MD (University Hospital Leipzig, Germany) in a first-time data release.
The LimFlow system facilitates the percutaneous creation of a functional vascularization channel to the foot in patients with no-option chronic limb threatening ischemia (CLTI). By diverting oxygenated blood around diseased and occluded arteries into adjacent veins, inflow and outflow can be improved, thus increasing perfusion to the critically ischemic foot.
The ALPS registry is being conducted in four centers in Alkmaar (the Netherlands), Leipzig, Paris (France,) and Singapore – all multidisciplinary centers with integrated wound care. This two-year retrospective evaluation was conducted in a cohort of 32 consecutive patients treated with the LimFlow system between 2014 and 2018.
Procedures were performed by a variety of operators, noted Dr Schmidt, including angiologists, interventional radiologists, and vascular surgeons.
The study’s primary endpoint was amputation-free survival at six months. Secondary endpoints included wound healing, limb salvage, and survival at 6, 12, and 24 months.
Patients with no-option CLTI, classed as Rutherford 5 and 6, were included in the study. Exclusion criteria were acute limb ischemia, extensive tissue loss, infection precluding limb salvage, and a known history of deep vein thrombosis.
As Dr Schmidt explained, LimFlow has built several devices dedicated to the pDVA procedure. The procedure is carried out by first advancing a venous ultrasound catheter into the tibial vein, while an arterial ultrasound catheter is advanced simultaneously into the target artery. Once the crossing site is reached, the arterial ultrasound catheter is rotated until peak ultrasound signal is achieved, indicating the optimal crossing point. After crossing, a valvulotome is introduced to destroy valves at the bottom of the foot. Then, forward flow is achieved by way of stent graft placement.
Dr Schmidt presented a case example of a 65-year-old patient who was on chronic dialysis, with forefoot gangrene. Several PTA attempts had previously and unsuccessfully been made, and the patient had calcified foot arteries precluding further attempts at PTA or bypass. “The procedure is fairly easy, I would say,” he said. “On the monitor, you can see whether these catheter tips are close to each other. Then we fire the needle from the artery to the vein. You take the balloons and wires down to destroy the valves with the valvulotome, and finally you take covered stents down to the foot. Blood then streams very quickly down.”
Describing the ALPS patient population, he continued, “Most patients [63%] were male. Regarding the SVS WIfI score, many of them were high-risk patients. There were also a lot of renal insufficiency patients [53%], with 16% on chronic dialysis. Many were Rutherford category 5 [69%], and a third were category 6 [31%]. All patients’ wounds were ischemic, so these were really desperate patients in their baseline characteristics.”
In 86% of cases, the posterior tibial artery was connected to the veins, the anterior tibial in 10%, and the popliteal artery in 4%.
“The success rate of the procedure was really quite high at 97%,” continued Dr Schmidt. “Amputation-free survival out to two years was 67%. This is really quite an impressive number for these no-option patients. Survival rate at one year was 84%, at two years 80%. Freedom from major amputation was 80% after 12 months and after two years. Again, this is impressive.
“Complete wound healing was achieved in 73% at two years. This plateaued after 12 months. Median time for complete wound healing was about five months. This compares quite well with other registries dealing with CLI or severe CLI.”
A proportion of patients also underwent transcutaneous oxygen pressure (TcPO2) measurement follow-up over this two-year period. It was found that TcPO2 rose significantly in a mean of 45 days from baseline.
Dr Schmidt concluded, “This is the largest study of no-option CLI patients treated with the LimFlow device, showing mid- and long-term results. In this complex group, high technical success was achieved with very good amputation-free survival out to two years. Wound healing was achieved in the majority of the patients and the perfusion as measured by TcPO2 was also impressive.
“We think that, in selected patients with really no options, pDVA may be something we can offer for these patients, who otherwise are designated for major amputations.”