Effects Of Continuous Positive Airway Pressure Treatment On Left Ventricular Geometry In Patients With Obstructive Sleep Apnea Syndrome:A Six Month Clinical Study

Objective:To Observe the therapeutic effect of nasal continuous positive airway pressure treatment(CPAP) on Left Ventricular Geometry in patients with obstructive sleep apnea syndrome(OSAS) by echocardiography.Methods:Continuously enrolled 87 patients who suspected OSAS base on a history of snoring hospitalized at department of respiration, First Affiliated Hospital of Shanxi Medical University, with diagnosed OSAS by polysomnography with apnea-hypopnea index(AHI) ≥5 times per hour,and with CPAP treatment a period of6 months or more. Including 96 males and 11 females, age range from 28 to 72 years.Measured blood pressure in a fixed time at day and night. Blood examinations and echocardiography test were conducted next morning. Based on relative wall thickness(RWT) ≥0.42 and left ventricular mass index(LVMI) ≥46.7g / m2.7(female) or 49.2g/ m2.7(male), patients were divided into four patterns: normal geometry(NG),concentric remodeling(CR), eccentric hypertrophy(EH) and concentric hypertrophy(CH). Record cardiac structure and function parameters by echocardiography.Univariate and multivariate logistics regression analysis were used to determine the factors associated with concentric hypertrophy. The clinical and echocardiographicparameters were reassessed after six months of CPAP treatment. Observe the change of different left ventricular geometry.Results:(1)Among the 87 patients with OSAS,7 patients are NG(8.0%),24 patients are CR(27.6%),40 patients are CH(46.0%) and 16 patients are EH(18.4%). The OSAS patients satisfied the treatment indications had a higher proportion of concentric patterns(CH+CR). Univariate Logistic regression analysis showed that the apnea hypopnea index, the lowest oxygen saturation, body mass index and hypoxemia index were significantly associated with CH. In multivariate analysis of these factors, AHI considered to be an independent impact factor significantly associated with CH(odds ratio: 1.06, P <0.05).(2) After six months of CPAP treatment, the left ventricular geometry of patients with OSAS has changed: one patient from NG to CR, 8 patients from CR to NG, 5 from CH to NG, 16 from CH into CR, 2 from EH to CH.(3)echocardiographic parameters: Compared with the patients before CPAP treatment,IVST, PWT, LVMI decreased, E/A, Em/Am increased, DT decreased, the difference was statistically significant(P <0.05).Conclusion:(1)OSAS patients had a higher proportion of concentric patterns. Left ventricular geometry is dynamically changed, and four patterns can be transformed into each other.(2)Concentric LV geometry patterns were able to be reversed with six months of CPAP treatment.(3)AHI is an independent impact factor significantly associated with CH.