Results of the initial trial of the system in 126 patients with a mean body mass index of 28.4 kg/m2 were published last year (N. Engl. J. Med. 2014;370:139-49). At 12 months of follow-up, patients experienced a 68% overall reduction in their apnea-hypopnea index (AHI) score, from a preoperative mean of 29 to a postoperative mean of 9. In addition, patients had a 70% overall reduction in their oxygen desaturation index (ODI). The researchers also observed normalization of patient-based outcomes, with improvement in the Functional Outcomes of Sleep Questionnaire score and reduction of the Epworth Sleepiness Scale score to a level of 10 on average. “We also saw a reduction of snoring,” said Dr. Gillespie, who was a member of the research team. “Snoring went from 72% of patients having severe, annoying snoring to the point where a bed partner leaves the room, to 15% postoperatively.” Even so, 96% of patients who had a previous history of uvulopalatopharyngoplasty (UPPP) or laser-assisted uvulopalatoplasty (LAUP) still had tongue-based collapse after 12 months of follow-up. “But we found that their response to this therapy was just as good as people who had never had a UPPP or LAUP,” Dr. Gillespie said at the meeting, jointly sponsored by the Triological Society and the American College of Surgeons. “So it seems like patients who have failed UPPP are still good candidates for upper airway stimulation therapy.”
Dr. Gillespie noted that selection criteria for the trial were limited to patients with a BMI of less than 32 kg/m2 and to those who did not have complete circumferential collapse at the level of the soft palate on preoperative drug-induced endoscopy. These criteria were based on an earlier pilot study that showed that patients with complete circumferential collapse at the level of the soft palate did not respond to upper airway stimulation (J. Clin. Sleep Med. 2013;9:433-8).
Dr. Gillespie disclosed that he has received research support from Inspire Medical Systems, Olympus, and Surgical Specialties. He is also a consultant for those companies as well as for Medtronic.
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