Influence of application of the new rule for hypopnea in cardiac patients

Abstract

Introduction In 2012, American Academy of Sleep Medicine (AASM) proposed a new rule for hypopnea in adults (Version 2), where hypopnea is scored when the flow signal excursions drop by i‘Ý30% of pre-event baseline accompanied by i‘Ý3% desaturation or arousal.The phase or the temporal shape of oxygen saturation of central hypopnea or mixed hypopnea is very different from those of obstructive hypopnea. Many patients with heart disease have more central apnea including Cheyne Stokes respiration (CSR) and mixed apnea and, therefore, application of the new rule may bring about a significant change in the judgment of sleep disordered breathing, especially in patients with heart disease.Thus, we analyzed and compared the respiratory events using both version 1 (AASM 2007, alternative rule) and version 2 rules. Materials and methods The subject comprised of 75 patients who underwent Full PSG at our sleep laboratory.Patients were classified into those without heart disease ( n = 20, age 52i‘A15 years, male 85%), with heart disease ( n = 55, age, 62i‘A15 years, male 76.2%).The patients with heart disease were further divided into those who mainly had CSA (CSAi‘Ý50% and AHIi‘Ý5/h, n = 13, age 63i‘A18 years, male 85%) and those without CSA dominancy.Data were analyzed using both version 1 and 2 rules and compared between them. Results The mean apnea–hypopnea indices (AHI) of the group without heart disease by version 1 and 2 were 29i‘A20/h vs 30i‘A20/h respectively ( P = ns).Correlation coefficient between both analysis was y = 1.03x, R2 = 0.996.The mean AHI of the group with heart disease was 35i‘A20/h and 36i‘A20/h respectively ( P = ns).Correlation coefficient between both was y = 0.98 x + 2.29 and R 2 = 0.995.The mean AHI of the group with CSA dominancy was 44i‘A18/h vs 45i‘A17/h respectively ( P = ns).Correlation coefficient between both was y = 1.02 x and R 2 = 0.994. Conclusion Though there may be a substantial difference between the AHI results when analyzed using both versions of criteria in the cardiac or non-cardiac patients especially with low AHI, there was no significant difference among the groups as a whole.Thus, there may not be any serious problem by the analysis with the new version rule in these populations. Acknowledgement There is no COI in all authors.