Improving Patient Outcomes with Longitudinal Monitoring During Inspire Titration with Wesper Lab

By Dr. Chelsie Rohrscheib, PhD, & Dr. Ruchir Patel, M.D. FACP, Medical Director and Founder at The Insomnia and Sleep Institute of Arizona, this article discusses a study that improves the titration process for Inspire Hypoglossal Nerve Stimulation (HGNS) therapy in patients with obstructive sleep apnea (OSA) by incorporating Wesper Lab's home sleep apnea tests (HSAT) for frequent, longitudinal monitoring. Traditional titration, which can take 90-120 days, requires gradual adjustments to the device settings, but the study's optimized protocol shortened this period to an average of 63 days. By adjusting the stimulation levels every few days and monitoring OSA severity through Wesper, the study demonstrated a 68% reduction in Apnea-Hypopnea Index (AHI) and improved oxygen levels. This new approach significantly enhanced patient outcomes and efficiency while reducing over-titration risks, ultimately providing faster relief for patients and reducing the burden on clinicians.

Obstructive sleep apnea (OSA) is a common and serious sleep disorder in which the muscles in the throat intermittently relax and block the airway during sleep. This leads to repeated episodes of breathing cessation (apnea) or shallow breathing (hypopnea), causing disruptions in sleep quality and reduced oxygen levels. Untreated OSA can result in cardiovascular problems, daytime fatigue, and a variety of other chronic health issues.

Traditional treatments for OSA, such as continuous positive airway pressure (CPAP) therapy, can be effective but are often associated with poor compliance due to discomfort or inconvenience. Hypoglossal nerve stimulation (HGNS) therapy via the Inspire device has emerged as a promising alternative for patients with moderate to severe OSA who cannot tolerate CPAP.

In Inspire therapy, a small device is implanted in the chest that stimulates the hypoglossal nerve, which controls the muscles of the tongue. By stimulating the nerve during sleep, the tongue is repositioned to prevent airway obstruction, allowing the patient to breathe more easily. While this therapy is effective, the process of titration – adjusting the stimulation parameters to optimize patient comfort and efficacy – can be lengthy. This titration process involves fine-tuning the device’s settings over time to achieve the best possible outcomes in reducing apnea episodes and improving oxygen levels.

Titration for Inspire is often a prolonged process, typically taking anywhere from 90 to 120 days, due to the need for gradual adjustments and careful monitoring of the patient’s response. This extended timeline can delay the benefits of the therapy and may cause discomfort or suboptimal outcomes if the settings are not correctly adjusted. Thus, efforts to streamline and enhance this process are crucial for improving patient outcomes.

A recent study aimed to improve the titration process of Inspire therapy by incorporating a novel approach using home sleep apnea tests (HSAT), Wesper Lab, for longitudinal monitoring. The objective was to determine whether frequent assessments of treatment efficacy through HSAT could reduce the overall duration of the titration process while maintaining or improving clinical outcomes.

The study was conducted at a Sleep Clinic in Arizona, USA, and included 30 adults undergoing titration for Inspire implants between January and October 2023. Traditionally, after Inspire device activation, patients undergo a long series of clinic visits and sleep studies to adjust the device's stimulation parameters, which typically takes several months. The revised protocol in this study introduced more frequent monitoring by Wesper Lab and Inspire stimulation adjustments.

The optimized protocol began with activating the Inspire device three weeks post-surgery. After activation, the stimulation amplitude was increased by 0.1 volts every two to four days. To ensure that the data was accurate and to avoid the "first night effect" (anomalous sleep data due to adaptation to the new sleep environment), patients were advised to conduct a Wesper test on the second night following each amplitude increase. This allowed clinicians to objectively assess the effectiveness of each adjustment.

Patients returned for follow-up visits every two weeks, where the Wesper data was reviewed to track improvements in their Apnea-Hypopnea Index (AHI) and oxygen saturation (SPO2), both critical indicators of OSA severity. If patients showed significant improvements and were asymptomatic, an in-lab titration study was conducted 10 to 12 weeks post-activation to finalize the optimal settings.

The results of this study were promising. On average, the new care protocol shortened the titration process to 63 days (Figure 1).

Figure 1: The Average Inspire titration time for the optimized titration protocol and the recommended protocol by Inspire Medical Systems Inc. 

Remarkably, 86.6% of patients completed the program before 90 days, and 60% finished the program in 60 days or less (Figure 2). This marks a substantial reduction compared to the traditional 90- to 120-day process.

Figure 2: The percentage of patients in the optimized protocol that completed Inspire titration in 90 days or less. Overall, most patients completed titration sooner than the recommended 90-120 days.

In terms of clinical outcomes, the mean reduction in AHI was 68%, with patients experiencing a decrease in AHI by an average of 15.21 points, which is higher than the recommended 50% reduction by Inspire Medical System Inc. (Figure3). 

Figure 3: The patients that underwent the optimized protocol had a larger percent reduction in their AHI than the recommended protocol.

Additionally, patients showed a 4.31% improvement in minimum oxygen saturation levels, highlighting the efficacy of the therapy in improving oxygen levels during sleep.

The use of longitudinal monitoring with Wesper throughout the Inspire titration process has proven to be an effective way to reduce the time required to achieve optimal therapy settings while maintaining or improving patient outcomes. By allowing frequent, objective assessment of OSA severity with each adjustment, this protocol minimizes the risk of over-titration, ensuring that stimulation levels are comfortable for the patient while maximizing therapeutic benefit.

This approach also allows for the early identification of cases where alternative Inspire electrode configurations may be necessary, reducing the likelihood of treatment delays. Ultimately, this study demonstrates that Inspire titration can be made more efficient, reducing the burden on patients and clinicians while delivering the full therapeutic benefits of Inspire for OSA management.