Six-Month Data Presented From CSI's LIBERTY 360° Study of Treatment for Lower Extremity PAD

February 6, 2017—Cardiovascular Systems, Inc. (CSI) announced that 6-month data from the LIBERTY 360° study were presented by William Gray, MD, at ISET 2017, the 29th International Symposium on Endovascular Therapy in Hollywood, Florida. The company advised that 1-year data from the study will be released later this year. Thirty-day data were presented in August 2016.

The LIBERTY 360° study is evaluating the acute and long-term clinical and economic outcomes of peripheral vascular interventions (PVI) in treating patients with symptomatic lower-extremity peripheral artery disease (PAD). The study demonstrated that PVI can be successful in treating patients in all Rutherford class (RC) categories. The data also suggest that watchful waiting for patients in RC 2 to 3 and primary amputation for patients in RC 6 may not be necessary.

According to the company, LIBERTY 360° is a prospective, observational, multicenter, postmarket study that enrolled more than 1,200 patients at 51 sites across the United States, including 501 patients with claudication (RC 2 to 3), 603 patients with critical limb ischemia (CLI; RC 4 to 5), and 100 patients with the most severe form of CLI (RC 6). Enrollment was completed in February 2016 and patients will be followed for up to 5 years.

In the study, physicians were able to use any US Food and Drug Administration-approved device, including CSI’s Diamondback 360° peripheral orbital atherectomy system. The percutaneous Diamondback device is indicated for use as therapy in patients with occlusive atherosclerotic disease in peripheral arteries and stenotic material from artificial arteriovenous dialysis fistulae.

As summarized by CSI, the findings suggest that PVI can restore RC 4 to 5 patients with CLI status (limb pain at rest, cold and/or numbness in feet, open or nonhealing wounds on toes or foot) to moderate claudicant status (limb pain during movement). In addition, the data through 6 months demonstrate that PAD patients (RC 2 to 6) after PVI have maintained good outcomes and positive changes in Rutherford classification.

In the company's announcement, Dr. Gray commented, “Following endovascular intervention, we saw a marked improvement across all Rutherford classes at 6 months: RC 4 to 5 and RC 6 patients showed continued improvement from 30 days to 6 months, while RC 2 to 3 patients maintained improvement at 6 months. We also saw a high freedom from major adverse events across all classes. This suggests that endovascular intervention is an alternative treatment option in place of watchful waiting or even primary amputation.”

After endovascular intervention, patients who presented with baseline RC 2 to 3 (average, 2.8) improved to RC 1.3 (average) at 30 days and were RC 1.4 (average) at 6 months; RC 4 to 5 patients (average, 4.5) improved to RC 3.1 at 30 days and RC 2.3 at 6 months; and RC 6 patients improved to RC 5.5 at 30 days and RC 4.6 at 6 months.

At 6 months, freedom from major adverse events (a composite of major amputation, target vessel revascularization, and death) was 92.6% in RC 2 to 3, 81.2% in RC 4 to 5, and 73.7% in RC 6 patients. In RC 2 to 3, RC 4 to 5, and RC 6 patients, respectively, freedom from major amputation was 99.8%, 96.8%, and 87.1%; freedom from target vessel revascularization was 93%, 83.1%, and 85.1%; and freedom from death was 97.1%, 95.3%, and 85.1%.

CSI also noted that in the VascuQoL patient-reported, PAD-specific, health-related quality-of-life questionnaire, patients in the LIBERTY 360° study reported improved quality of life across all Rutherford classes, including such measures as physical activity, symptoms, and pain.

During a concurrent session at ISET, study investigator Jihad Mustapha, MD, stated, “LIBERTY 360° is novel in that it addresses all Rutherford classes, including class 6, representing some of the most challenging and life-threatening PAD cases. Six-month data suggests that these patients can be treated successfully with endovascular interventions—a significant step in establishing a new standard of care for this difficult-to-treat population."

According to CSI, it was also noted at ISET that the "2016 American Heart Association/American College of Cardiology Guidelines on the Management of Patients with Lower-Extremity PAD" (published online in Circulation in November) support this data, stating that revascularization is a reasonable treatment option for patients with lifestyle-limiting claudication and an inadequate response to medical management and exercise; and an evaluation for revascularization options should be performed by an interdisciplinary care team before amputation in the patient with CLI.