Medtronic’s ABRE Study Subanalysis Shows Obesity Paradox After Iliac Vein Stenting

November 3, 2024—Medtronic recently announced results from a subset analysis of the ABRE study showing an obesity paradox reflected in outcomes after iliac vein stenting. The subanalysis of the ABRE study sought to assess the impact of body mass index (BMI) on post–venous stenting outcomes.

The company noted that historically, obesity has been viewed a potential hindrance to venous stenting, with expectations of poorer patient outcomes because of the associated higher comorbidity risks.

The subanalysis outcomes were presented by Erin Murphy, MD, at the AVLS 2024, the 38th annual congress of the American Vein & Lymphatic Society held October 10-13 in Chicago, Illinois. Dr. Murphy is Director, Venous and Lymphatic Institute at Sanger Heart and Vascular, Atrium Health in Charlotte, North Carolina. The subanalysis abstract is available here on the AVLS 2024 website.

Medtronic stated that the ABRE study was designed to evaluate the safety and efficacy of the company’s Abre venous self-expanding stent system in patients with symptomatic iliofemoral venous outflow obstruction. ABRE enrolled 200 patients at 24 global study sites.

As summarized by the company, average age was 51.5 years, 66.5% were female, average BMI was 29.5 kg/m², and 52.0% had a history of venous thromboembolism. Patients in the study were followed for 36 months.

The ABRE study’s primary effectiveness endpoint was primary patency at 12 months; the primary safety endpoint was major adverse events at 30 days; and secondary endpoints included changes in venous function, as measured by revised Venous Clinical Severity Score (rVCSS), and quality of life, as measured by VEINES-QoL.

For the subanalysis, patients were categorized by the World Health Organization (WHO) BMI groups and were distributed as follows: underweight, 2%; normal weight, 27%; preobesity, 25%; class I obesity, 26%; class II obesity, 11%; and class III obesity, 9%.

As outlined by Medtronic, the study found the following key results:

• The preobesity and obesity class I, II, and III groups showed increasingly higher baseline rVCSS compared to underweight and normal-weight patients.
• After 6 months, improvement in rVCSS was constant across all BMI groups except for the underweight group.
• As BMI increased, the baseline VEINES-QoL scores worsened.
• Improvement in VEINES-QoL at 6 months was constant across all BMI groups except for the underweight group.
• BMI was not found to be a factor in VEINES-QoL change from baseline to 6 months.
• The preobesity, obesity class I, and obesity class II groups paradoxically trended toward higher patency rates at month 36 than the normal-weight group.
• The obesity class III group demonstrated a trend toward worsening patency, although the 95% CIs overlapped for all three groups and the subgroups were small.
• There was no significant difference in underlying disease cohort (nonthrombotic, postthrombotic, acute deep vein thrombosis) across BMI categories.

Based on these key findings, Medtronic summarized the study’s conclusions as follows:

• Initial patient presentations worsened with increasing BMI, as reflected by the baseline rVCSS and VEINES-QoL scores.
• All patients demonstrated an improvement in venous functional and QoL parameters.
• The preobesity, obesity class I, and obesity class II groups paradoxically trended toward higher patency at 36 months compared with the normal-weight group; however, there was overlap in 95% CIs for all three groups and the subgroups were small.
• Obesity class III patients (BMI > 40 kg/m²) displayed the most severe presentations, similarly gained benefits from stenting, and had the lowest 36-month patency, indicating potential higher risk in this group independent of disease cohort (postthrombotic, nonthrombotic, acute deep vein thrombosis).