Pulse rate variability as detected by pulse oximetry could serve as a useful biomarker for stroke risk stratification in patients with obstructive sleep apnea (OSA), according to the results of a recent study published in the American Journal of Respiratory Critical Care Medicine.
Researchers measured pulse rate variability via overnight oximetry during diagnostic sleep studies in patients with OSA having 5 or more events per hour. The primary study outcome was first episode of stroke. Standard deviation of normal-to-normal beat intervals and successive normal-to-normal differences were used to retrospectively correlate pulse rate variability to health outcomes.
Among the 6075 stroke-free patients with OSA, the mean age was 62 years and the average apnea-hypopnea index was 28 events per hour. A total of 2536 patients were correctly treated via positive airway pressure and 3539 patients were nonadherent to positive airway pressure or did not receive any active OSA therapy.
After the median follow-up of 6.5 years, 459 patients had died, and 177 patients had received a diagnosis of stroke. Overall, patients with lower sympathetic/parasympathetic tone (LF/HF ratio) were at higher risk for stroke. The association appeared to be stronger in patients with severe OSA.
“Individuals with OSA, particularly those with severe disease, who demonstrate low sympathovagal balance (LF/HF) are at increased risk [for] stroke,” the study authors wrote. “[Pulse rate variability] indices derived from pulse oximetry data, readily available in routine sleep recordings, might provide a useful biomarker for stroke risk stratification.”
Sabil A, Gervès-Pinquié C, Blanchard M, et al; on behalf of the ERMES Study Group. Overnight oximetry-derived pulse-rate variability predicts stroke risk in patients with obstructive sleep apnea. Am J Respir Crit Care Med. Published online April 9, 2021. doi:10.1164/rccm.202101-0109LE