Effect of CPAP on circulating levels of MPO and MMP-9 in adults with coronary artery disease and obstructive sleep apnoea: the RICCADSA randomized controlled trial

Abstract

Background: Increased levels of myeloperoxidase (MPO), as an oxidative stress marker, as well as matrix metalloproteinase-9 (MMP-9), as a destabilizer of plaques, are known to be elevated in patients with coronary artery disease (CAD).

Objectives: To evaluate the effect of continuous positive airway pressure (CPAP) treatment on MPO and MMP-9 after one year in a revascularized CAD cohort with obstructive sleep apnoea (OSA).

Methods: OSA patients from the RICCADSA cohort with an apnoea-hypopnoea index ≥15/h and Epworth Sleepiness Scale <10 were randomized to CPAP (n=105) or no CPAP (n=115). Blood samples were obtained at baseline and 1-year follow-up. MPO and MMP-9 were measured by immunoassay (Luminex).

Results: CPAP reduced MMP-9 levels while there was an increase in the control group. No significant difference was observed between the groups regarding the MPO levels (Table 1). In a linear regression analysis, CPAP use (h/night) was associated with the magnitude of change in MMP-9 after adjusting for age, sex, body-mass-index, current smoking, and baseline MMP-9 levels (standardized β=-0.08 [CI, -21.0 – -3.3], p= 0.007).

Conclusions: CPAP treatment decreased MMP-9 whereas no significant changes were observed in MPO levels in this revascularized cohort with OSA who were not sleepy at baseline.