0566 Baseline Characteristics of Central Sleep Apnea Patients Treated with Transvenous Phrenic Nerve Stimulation in the reST Study

Abstract Introduction The remedē System® Therapy Study (reST) is a real world evaluation using transvenous phrenic nerve stimulation (TPNS) to treat adults with moderate-to-severe central sleep apnea (CSA). Based on previous clinical trials, it was expected that most patients with CSA would have heart failure (HF). However, recent CSA prevalence publications demonstrated the opposite. We present the baseline characteristics of patients with CSA treated with TPNS. Methods Adult subjects determined eligible for a commercial TPNS device implant by routine clinical PSGs were consented to participate in the trial. Baseline assessments were performed and medical history collected. Patients will be followed for ≥1 year following therapy activation; follow-up is ongoing. This report describes the baseline characteristics of the patient population. Results Twenty-nine sites enrolled a total of 197 subjects (171 United States & 26 the Netherlands) between July 2019 and March 2025. Median [Q1-Q3] age was 70 [61-76] years, 82% were male, and 97% white race. Body mass index was 28.7 [25.8-31.6] kg/m2, with neck size 41 [28-44] cm. Patients had moderate-to-severe CSA with site-reported apnea-hypopnea index of 46/hour [30-64], including central apnea index of 24/hour [13-38]. Despite a range of comorbidities among patients, HF was documented in just 23%. Other cardiovascular conditions were more prevalent, including hypertension (70%), hyperlipidemia (65%), coronary artery disease (37%), atrial fibrillation (34%), and prior stroke (14%). Non-cardiac issues such as depression (27%), diabetes (26%), and renal disease (18%) were also present. Additionally, 22% of patients used narcotics, and 89% had previously failed another CSA therapy, most often CPAP (79%), Bi-PAP (39%), or ASV (32%). Lastly, almost 20% were from high altitude locations (>5,000 feet). Conclusion Patients implanted with TPNS had significant co-morbidities. However, HF was much less common than anticipated. This finding could be due to CSA being present in clinical practice with a wider range of underlying causes beyond HF, or undiagnosed early-stage HF. Alternatively, it may reflect referral bias for this specific therapy, with patients selected because of prior treatment failures or other comorbidities. These possibilities highlight the importance of recognizing CSA in a diverse patient population and underscore the need for multidisciplinary team management. Support (if any) ZOLL Respicardia, Inc.