Loop Gain in the Reversion of OSA Treated by Either CPAP or Cardiac Valve Replacement

Between January 31, 2020 and June 30, 2023, 300 patients with valvular heart disease waiting for cardiac valve replacement in Department of Cardiovascular Surgery were screened for obstructive sleep apnea (OSA) by full-night polysomnography. Of them, 40 OSA patients were enrolled and randomly received CPAP treatment and non-CPAP treatment (20:20). The CPAP treatment group received both baseline medicine and CPAP treatment. The full-night CPAP treatment was conducted from 21:00 pm to 6:00 am for 7 days preoperatively. The non-CPAP treatment group received baseline medicine treatment. LG and related parameters were collected at the first day of treatment in non-CPAP group and both first and last day of treatment in CPAP group. Sleep parameters including apnea-hypopnea index (AHI), mean and lowest SPO2, and clinical evaluations including New York Heart Association (NYHA) classes, electrocardiographic, echocardiographic, arterial blood gas analysis findings, baseline medication, and 6-minute walk test were recorded. Operation related parameters (duration of operation, duration of cardiopulmonary bypass and bleeding volume) were recorded. Postoperative adverse events such as duration of ICU stay, postoperative duration of mechanical ventilation, pacemaker use, complicated infection and reintubations were recorded. A full-night polysomnography as well as LG and related parameters were re-examined before discharge from hospital. The changes of AHIs, mean and lowest SPO2, LG and related parameters between pre- and post-operative polysomnography parameters were calculated. The correlation between changes of polysomnography and LG parameters pre- and post-CPAP in CPAP group were analyzed. The correlation between changes of polysomnography and LG parameters pre- and post-operative in both CPAP and non-CPAP group were analyzed. The differences of polysomnography and LG parameters, and post-operative adverse events between CPAP and non-CPAP treatment group were analyzed.