Pilot Study of a Compact Pneumatic Compression Device for Patients with Lymphedema

Introduction, Objectives, and/or Purpose: Lymphedema (LE) is characterized by increased collection of lymphatic fluid in the body and affects over 200 million individuals worldwide. In Western countries, Chronic Venous Insufficiency is the most common cause of lower extremity LE. People living with LE can experience pain, skin atrophy, increased bacterial infection, a negative effect of quality of life (QoL), and increased risk of developing anxiety and depression.

Treatment for LE usually includes intensive complete decongestive therapy from healthcare professionals followed by an ongoing maintenance phase where the patient undertakes self-management. The need for daily self-management to slow the progression of LE and reduce the risk of complications may be time-consuming and burdensome for the patient. Maintenance therapy for LE can include regular home use of a pneumatic compression device (PCD), which has been shown to have several benefits: reductions in limb circumference, rate of complications and healthcare expenditure, and improvements in QoL. However, the utility of this therapeutic approach and persistent long-term home usage of PCD therapy is negatively impacted by the features of currently available devices, which are often large, bulky, and difficult to use.

Aria Free™ (Figure 1) is a compact, user-friendly PCD that has recently been shown to be: comfortable, easy to use, effective in reducing leg edema in a monitored clinical environment and the smallest and lightest PCD for the lower limb on the market. This study’s primary objective assessed the usability of Aria Free during at-home usage by patients with lower limb lymphedema (LLL). Secondary endpoints evaluated therapy usage, comfort, garment fit, the Aria smartphone application ease of use, and therapy efficacy.

Methods: This single-center, open-label pilot study, conducted between June and August 2020, was approved by the Advarra IRB (Pro00039074). Eligible patients were ≥18 years, had LLL, met all inclusion and no exclusion criteria. Ten subjects were planned; 90% of usability issues would be identified if up to 2 withdrew. Statistical analyses used SAS v9.4.

Subjects were demonstrated the Aria Free via videoconference and asked to use it for 60 minutes for 7 consecutive days. Subjective measures were rated on a Likert scale, 0 to 10 (most favorable); the median compared to a reference score of 6. Subject-reported usage data were compared to device-recorded data. Smartphone application ease of use was rated on a Likert scale, 1 to 5 (most favorable).

Subjects were given instructions on taking leg measurements. Change in limb size was calculated as the volume after therapy minus the volume before therapy using the truncated cone method. Daily change in limb volume (LV) was assessed using a repeated measures mixed-effects model to account for variability within patients. Weekly change in volume was calculated as a one-sided t-test of the arithmetic average of the daily changes per subject.

Results: Twelve subjects were screened and enrolled. However, one subject withdrew for an unstated reason, and two subjects experienced non-serious adverse events and ultimately terminated participation on the study. Data was analyzed and interpreted on the nine subjects who completed the study. Eighty-nine percent were female, and the mean age was 51 years. Two participants were not current users of a pneumatic compression device.

Subject-reported median usability score for Aria Free was 9 (p=0.01) on an 11-point Likert scale, statistically significantly greater than a reference score of 6. Median scores for assessing usability were based on subject ratings regarding ease of setting up pump and garment, and making all necessary connections to start therapy (median score of 9); fitting the garment (median score of 9); and turning the device on and off (median score of 10). Therapy comfort and garment fit were also favorable with scores of 10 (P=0.009) and 8, respectively, on an 11-point Likert scale. Likert scale scores for Aria Free setup and therapy can be found in Table 1.

All subjects who completed the study adhered fully to the therapy schedule. Self-reported device usage was an average of 60 minutes/day, and objective usage based on downloaded device data was 59.93 minutes per session. Two-thirds of subjects reported their ease of use of the smartphone application, with mean score of 3.33 out of a 5-point Likert scale; these subjects stated that they liked the ability to track their therapy progress and the session timer.

Pre- and post-therapy limb volume measurements were provided by all subjects across all seven days of therapy. The estimated mean ± standard error daily change in limb volume for each session of the 7-day treatment period was –1.94% ±0.68% (95% confidence interval –3.51, –0.36; p=0.01), with no significant time interaction (i.e. daily changes did not vary significantly over the 7-day treatment period). There was also a significant reduction in limb volume over 1 week of device usage (p=0.01 vs. prior to therapy initiation).

Conclusion(s): This pilot study showed that subjects found the compact Aria Free easy to set up and use at home. Lower LV reductions were achieved on a daily basis and cumulatively over one week. These findings confirm and extend those of a recent study that showed good fit, usability, and patient satisfaction after a single in-person clinic session. Thus, the utility of Aria Free in the home environment over a longer treatment period was established.

Good usability and patient satisfaction, along with treatment benefits, were obtained with a “low touch” approach to treatment initiation. The trial design was changed to account for the COVID-19 pandemic-related restrictions of mid-2020. The study became 100% remote, with devices delivered to study participants via courier, and instructions provided via videoconference. The PI instructed subjects on how to use Aria Free during a planned 60-minute virtual visit. “High-touch” engagement was not required for successful initiation and use, indicating that Aria Free is user-friendly and intuitive.

The chronic nature of LE and the self-management required to slow progression and minimize complications can be time-consuming and burdensome for patients, which may contribute to reduced QoL and increased risk of mental health challenges. Underserved populations, such as those living in rural areas or of lower socioeconomical groups, may face additional difficulties regarding access to care and disease surveillance. Therefore, there is a need for patients to self-manage their LE utilizing resources that are effective, easy to set up, and can be used consistently outside of a clinical setting. Patient-rated measures included in this study are an important part of assessment of treatment options. There is a lack of data on the effects of currently available therapies on these important parameters.

The change to fully remote set-up provides a key strength for the effective contactless therapy initiation with Aria Free. However, data interpretation should be performed considering several limitations. The sample size was small, limiting statistical power. The lack of in-person contacts meant lower LV measurements were completed by subjects themselves rather than a trained clinician. Subjects were provided with detailed instructions on how to self-measure LV, but this approach may be unreliable (e.g. the patient may not be able to comfortably reach more distal lower limb points). Furthermore, the limb may not always be in the same position for each measurement; and changing limb position has been shown to reduce measurement reliability and increase measurement error at some sites.