Subclinical left ventricular systolic dysfunction detected in obstructive sleep apnea with automated function imaging and its association with nocturnal hypoxia.

BACKGROUND: Early detection of left ventricular (LV) dysfunction is crucial in obstructive sleep apnea (OSA) due to its close relationship with cardiovascular diseases. Global longitudinal strain (GLS) derived from automated function imaging (AFI) can precisely assess global longitudinal function. The aim of this study was to determine if LV GLS was reduced in patients with OSA and a normal LV ejection fraction (LVEF) and to assess any associated determinants. METHODS: Polysomnography (PSG) and echocardiography were done in consecutive patients with suspected OSA and normal LVEF in this prospective study. Patients were divided into two groups according to apnea-hypopnea index (AHI) (Group 1, normal or mild OSA: AHI < 15/h; Group 2, moderate-to-severe OSA: AHI ≥ 15/h). Clinical, PSG, and echocardiographic parameters were compared between the two groups and the associated factors were investigated. RESULTS: Of 425 consecutive patients, 244 were analyzed after exclusions. Patients in Group 2 had significantly worse GLS than those in Group 1 (p < 0.001). The prevalence of GLS reduction (defined as < - 19.7%) was 25% and 76%, respectively (χ2 = 34.19, p < 0.001). Nocturnal lowest pulse oxygen saturation (SpO2), AHI, body mass index (BMI), and gender were associated with GLS reduction (all p < 0.05). Further multivariate analysis showed that the lowest SpO2 (OR: 2.15), gender (OR: 2.45), and BMI (OR: 2.66) remained independent (all p < 0.05), and the lowest SpO2 was the most powerful determinant (χ2 = 33.0, p < 0.001) in forward regression analysis. The intra- and inter-operator variability for AFI and coefficient of repeatability was low even in those with relatively poor images. CONCLUSIONS: In patients with normal LVEF, more severe OSA was associated with a worse GLS. The major determinants were lowest nocturnal SpO2, gender, and obesity, but not AHI. GLS can be rapidly and reliably assessed using AFI.

Obstructive sleep apnoea, intermittent hypoxia and heart failure with a preserved ejection fraction.

Obstructive sleep apnoea (OSA) is recognised to be a potent risk factor for hypertension, coronary heart disease, strokes and heart failure with a reduced ejection fraction. However, the association between OSA and heart failure with a preserved ejection fraction (HFpEF) is less well recognised. Both conditions are very common globally.It appears that there are many similarities between the pathological effects of OSA and other known aetiologies of HFpEF and its postulated pathophysiology. Intermittent hypoxia induced by OSA leads to widespread stimulation of the sympathetic nervous system, renin-angiotensin-aldosterone system and more importantly a systemic inflammatory state associated with oxidative stress. This is similar to the consequences of hypertension, diabetes, obesity and ageing that are the common precursors to HFpEF. The final common pathway is probably via the development of myocardial fibrosis and structural changes in collagen and myocardial titin that cause myocardial stiffening. Thus, considering the pathophysiology of OSA and HFpEF, OSA is likely to be a significant risk factor for HFpEF and further trials of preventive treatment should be considered.

[Structure activity relationship of annonaceous acetogenins against multidrug resistant human lung cancer cell line A549/Taxol in vitro].

10 kinds of annonaceous acetogenins were selected for antitumor activity testing against human lung cancer cell line A549/Taxol and the structure activity relationship was analyzed.MTT assay was used to detect the inhibitory activities of 10 kinds of annonaceous acetogenins and positive drugs against A549/Taxol cells, respectively uvariamicin-Ⅲ(1), uvariamicin-Ⅱ(2), annosquacin D(3), desacetyluvaricin(4), annosquatin A(5), squamostatin D(6), bullatacin(7), squamocin(8), motrilin(9), annosquatin B(10), verapamil and cisplatin. Annonaceous acetogenins showed significant inhibitory activities against A549/Taxol cells, and were more potent than the positive drug verapamil and cisplatin.The more carbon atoms between the tetrahydrofuran ring and the lactone ring of annonaceous acetogenins exhibited more potency.Besides,ACGs with two substituted hydroxyl showed more potency than the compounds with three substituted hydroxyl in the bis-adjacent-THF ACGs. Furthermore, ACGs with three substituted hydroxyl showed more potency than the compounds with four substituted hydroxyl among the no bis-adjacent-THF ACGs.