Decreased right and left ventricular myocardial performance in obstructive sleep apnea

BACKGROUND: Obstructive sleep apnea (OSA) may predispose patients to congestive heart failure (CHF), suggesting a deleterious effect of OSA on myocardial contractility. METHODS: A cross-sectional study of 85 subjects with suspected OSA who had undergone their first overnight polysomnogram, accompanied by an echocardiographic study. Patients were divided according to the apnea-hypopnea index as follows: < 5 (control subjects); 5 to 14 (mild OSA); and >or= 15 (moderate-to-severe OSA). Right and left ventricular function was evaluated using the myocardial performance index (MPI) and other echocardiographic parameters. For the right ventricle analyses, we excluded patients with a Doppler pulmonary systolic pressure of >or= 45 mm Hg, while for the left ventricle we excluded patients with an ejection fraction of 相似文献   

Impact of obstructive sleep apnea on left ventricular diastolic function

The aim of this study was to investigate the impact of obstructive sleep apnea (OSA) on left ventricular (LV) functional changes by using tissue Doppler imaging-derived indexes in patients with OSA. We studied 62 patients classified into 3 groups, namely 18 with mild to moderate OSA, 24 with severe OSA, and 20 control subjects without OSA according to the apnea-hypopnea index (AHI) on complete overnight polysomnogram. All underwent conventional and tissue Doppler echocardiographies. Only early diastolic velocity (Ea; -6.2 +/- 0.3 vs -7.1 +/- 0.3 vs -7.3 +/- 0.3 cm/s, respectively, for the 3 groups, p = 0.023) was significantly decreased in the severe OSA group. Other echocardiographic parameters of diastolic function such as isovolumic relaxation time, deceleration time, mitral inflow early/late wave velocity ratio, and pulmonary vein systolic/diastolic pulmonary vein velocity ratio were comparable among the 3 groups. AHI was correlated only with tissue Doppler imaging-derived indexes of LV diastolic function (Ea r = -0.382, p = 0.002; Ea/late diastolic velocity r = -0.329, p = 0.009), but not with conventional Doppler indexes. AHI remained a significant predictor of Ea after adjusting for age, heart rate, fasting glucose level, blood pressure, body mass index, and LV mass index in a multiple stepwise linear regression model (p = 0.007). In conclusion, only patients with severe OSA showed a greater impairment of LV diastolic function. Of all echocardiographic parameters of diastolic dysfunction investigated, only Ea was identified as the best index to demonstrate an association between LV diastolic dysfunction and severity of OSA independently of body mass index, diabetes mellitus, and hypertension.     

Influence of obstructive sleep apnea on left ventricular mass and global function: sleep apnea and myocardial performance index

Obstructive sleep apnea (OSA) is associated with cardiovascular mortality and morbidity. It may predispose patients to left ventricular hypertrophy and heart failure. The aim of this study was to determine the left ventricular mass (LVM) and myocardial performance index (MPI) reflecting left ventricular global function in uncomplicated OSA patients. Sixty-four subjects without hypertension, diabetes mellitus, and any cardiac or pulmonary disease referred for evaluation of OSA underwent overnight polysomnography and complete echocardiographic assessment. According to the apnea hypopnea index (AHI), subjects were divided into three groups: group 1, control subjects with nonapneic snorers (AHI < 5, n = 18); group 2, patients with mild to moderate OSA (AHI: 5–30, n = 25); and group 3, severe OSA (AHI > 30, n = 21). Basic echocardiographic measurements, LVM, and LVM index were measured. Left ventricular MPI was calculated as (isovolumic contraction time+isovolumic relaxation time)/aortic ejection time by Doppler echocardiography. There were no significant differences in age, sex, body mass index, heart rate, and systolic and diastolic blood pressure among the three groups. Left atrium, interventricular septum, left ventricular posterior wall, left ventricular end-diastolic and end-systolic diameters, LVM mass, and LVM index were not significantly different among the three groups. Left ventricular MPI was significantly higher in severe OSA patients (0.64 ± 0.18) than in controls (0.49 ± 0.18; P < 0.05). There was no significant difference between controls (0.49 ± 0.18) and mild to moderate OSA (0.61 ± 0.16; P = 0.08) and between mild to moderate OSA (0.61 ± 0.16) and severe OSA (0.64 ± 0.18; P = 0.84). The present study demonstrates that patients with severe OSA have global left ventricular dysfunction.     

Severe obstructive sleep apnea is associated with left ventricular diastolic dysfunction

INTRODUCTION: Hypertension is common in patients with obstructive sleep apnea (OSA). However, the effect of OSA on ventricular function, especially diastolic function, is not clear. Therefore, we have assessed the prevalence of diastolic dysfunction in patients with OSA and the relationship between diastolic parameters and severity of OSA. METHODS: Sixty-eight consecutive patients with OSA confirmed by polysomnography underwent echocardiography. Diastolic function of the left ventricle was determined by transmitral valve pulse-wave Doppler echocardiography. Various baseline characteristics, severity of OSA, and echocardiographic parameters were compared between patients with and without diastolic dysfunction. RESULTS: There were 61 male and 7 female patients with a mean age of 48.1 +/- 11.1 years, body mass index of 28.5 +/- 4.3 kg/m(2), and apnea/hypopnea index (AHI) of 44.3 +/- 23.2/h (mean +/- SD). An abnormal relaxation pattern (ARP) in diastole was noted in 25 patients (36.8%). Older age (52.7 +/- 8.9 years vs 45.1 +/- 11.3 years, p = 0.005), hypertension (56% vs 20%, p = 0.002), and a lower minimum pulse oximetric saturation (SpO(2)) during sleep (70.5 +/- 17.9% vs 78.8 +/- 12.9%, respectively; p = 0.049) were more common in patients with ARP. By multivariate analysis, minimum SpO(2) < 70% was an independent predictor of ARP (odds ratio, 4.34; 95% confidence interval, 1.23 to 15.25; p = 0.02) irrespective of age and hypertension. Patients with AHI > or = 40/h had significantly longer isovolumic relaxation times than those with AHI < 40/h (106 +/- 19 ms vs 93 +/- 17 ms, respectively; p = 0.005). CONCLUSION: Diastolic dysfunction with ARP was common in patients with OSA. More severe sleep apnea was associated with a higher degree of left ventricular diastolic dysfunction in this study.     

Impact of obstructive sleep apnea on left ventricular mass and diastolic function

We wished to determine if obstructive sleep apnea (OSA) is associated with increased left ventricular mass (LVM) and impaired left ventricular diastolic function (LVDF) independently of coexisting obesity, hypertension (HTN), and diabetes mellitus (DM). Patients without primary cardiac disease, referred for evaluation of OSA (n = 533), had overnight polysomnography and Doppler echocardiography while awake. Patients were divided, according to the apnea-hypopnea index (AHI), into an OSA group (AHI > or = 5/h, n = 353) and a non-OSA group (AHI < 5/h, n = 180). In men, LVM was greater in the OSA group (98.9 +/- 25.6 versus 92.3 +/- 22.5 g/m, p = 0.023) despite exclusion of those with HTN and DM. A similar trend was noted in women. Regression analysis revealed that LVM was correlated with body mass index (BMI) (beta = 0.480, p < 0.0005), age (beta = 0.16, p = 0.001), and the presence of HTN (beta = 0.137, p = 0.003) in men and with BMI (beta = 0.501, p < 0.0005) in women, but not with AHI or oxygen saturation during sleep. The ratio of peak early filling velocity to peak late filling velocity (E/A), an index of LVDF, was similar in both groups (1.28 +/- 0.32 versus 1.34 +/- 0.31, p = 0.058); it was correlated with age (beta = -0.474, p < 0.0005), but not with AHI or oxygen saturation during sleep. We conclude that OSA is not associated with increased LVM or impaired LVDF independently of obesity, HTN, or advancing age.     

Right ventricular hypertrophy causes impairment of left ventricular diastolic function in the rat

Right ventricular (RV) pressure overload causes right ventricular hypertrophy in several types of pulmonary and congenital heart diseases. The associated cardiac dysfunction has generally been attributed to alterations in RV function. However, due to global neurohormonal adaptations and mechanical ventricular interaction left ventricular (LV) function could be affected as well.Therefore,LV function, RV function and their interaction were studied in rats with monocrotaline (MCT)-induced RV hypertrophy and control rats. MCT (30 mg/kg) was used to induce pulmonary hypertension, which resulted, after 28 days, in marked RV hypertrophy (RV-weight: control 220 ± 15,MCT 437 ± 34mg,p < 0.05). In Langendorff-perfused hearts with balloons inserted in both the LV and the RV, the diastolic pressure-volume relations showed increased stiffness, and relaxation was prolonged in the LV and RV in the MCT group compared to controls. In the MCT group, developed pressures were increased only in the RV. An increase of LV volume increased RV diastolic pressure to a similar extent in both groups. However, an increase in RV volume did not affect LV diastolic pressure in controls, but significantly increased LV diastolic pressure in the MCT group. LV and RV developed pressure-volume relations were not affected. Calculated circumferential end-diastolic wall stresses (σ) were larger in the MCT group (LV-σ: 0.55 ± 0.02, RV-σ: 1.94 ± 0.30 kN/m², both p< 0.05 to control) compared to controls (LV-σ: 0.34 ± 0.06,RV-σ: 1.23 ± 0.46 kN/m2). In the MCT group, collagen content was increased in the LV, septum and RV compared to controls. In conclusion, structural changes of the RV and LV result in depressed LV diastolic function during RV hypertrophy.     

Right ventricular hypertrophy detected by echocardiography in patients with newly diagnosed obstructive sleep apnea.

We used polysomnography, echocardiography and ventilatory measurements to study 50 patients suspected of having OSA to determine a link to RVH. Twenty-eight patients (56 percent) had OSA and 20 (71 percent) of those had isolated RVH. We evaluated patients with RVH and divided them into two groups, those with apnea and those without apnea. The patients with sleep apnea were younger, weighed more, had greater BSA and had lower average oxygen saturations during the sleep study period. We divided the group with apnea into those with RVH and those without it. Those patients with RVH had a higher AI, longer average apnea time, a greater duration of longest apnea and a lower average oxygen saturation for the period of the sleep study. In addition, those with RVH had a lower average oxygen saturation during each apneic episode with a p value equaling 0.09.     

Neurocognitive impairment in obstructive sleep apnea

Obstructive sleep apnea syndrome (OSAS) is a common disorder with far-reaching health implications. One of the major consequences of OSAS is an impact on neurocognitive functioning. Several studies have shown that OSAS has an adverse effect on inductive and deductive reasoning, attention, vigilance, learning, and memory. Neurocognitive impairment can be measured objectively with tests such as the Wechsler Adult Intelligence Scale-Revised, the Psychomotor Vigilance Task, the Steer Clear Performance Test, and tests of repetitive finger tapping. In children, OSAS may cause attention-deficit hyperactivity disorder in addition to behavioral problems and learning disabilities. Risk factors for cognitive impairment include increasing age, male sex, apolipoprotein E ε4 allele positivity, current cigarette smoking, obesity, hypertension, diabetes mellitus, metabolic syndrome, Down syndrome, hypothyroidism, significant alcohol consumption, stroke, and the use of psychoactive medications. At a cellular level, OSAS likely causes cognitive impairment through intermittent hypoxia, hormonal imbalance, and/or systemic inflammation, either independently or via the resultant endothelial dysfunction that occurs. Excessive daytime sleepiness should be measured and minimized in all studies of neurocognitive impairment. Recent studies have used functional and structural neuroimaging to delineate the brain areas affected in patients with OSAS with neurocognitive dysfunction. A common finding in several of these studies is decreased hippocampal volume. Other affected brain areas include the frontal and parietal lobes of the brain, which show focal reductions in gray matter. These changes can be reversed at least partially with the use of CPAP, which highlights the importance of early recognition and treatment of OSAS. The currently available data in this field are quite limited, and more research is needed.     

Prevalence of left ventricular hypertrophy in persons with and without obstructive sleep apnea

We investigated the prevalence of left ventricular hypertrophy (LVH) in persons with and without obstructive sleep apnea (OSA). Fifty-three persons had a nocturnal polysomnogram to diagnose OSA and 2-dimensional echocardiograms to measure left ventricular mass. OSA was considered mild if the respiratory disturbance index (RDI) was 5 to 15, moderate if the RDI was 15 to 30, and severe if the RDI was >30. LVH was diagnosed if the left ventricular mass index was >110 g/m in women and >134 g/m in men. LVH was present in 21 of 27 persons (78%) with moderate or severe OSA, in 6 of 13 persons (46%) with mild OSA, and in 3 of 13 persons (23%) with no OSA (P < 0.001 comparing moderate or severe OSA with no OSA and P < 0.05 comparing moderate or severe OSA with mild OSA). OSA was a significant independent predictor of LVH after controlling the confounding effects of hypertension with an odds ratio of 3.579 (95% confidence interval, 1.589-8.058).     

Aortic elastic properties and left ventricular diastolic dysfunction in patients with obstructive sleep apnea

Although the responsible mechanisms are not yet fully known, obstructive sleep apnea is associated with an increased risk for cardiovascular disease and events. The aorta is not only a conduit delivering blood to the tissues but is also an important modulator of the entire cardiovascular system, its elastic properties also affecting left ventricular function and coronary blood flow. The aim of this study was to determine left ventricular diastolic function and aortic elastic properties in patients with obstructive sleep apnea syndrome. Fourteen male patients with obstructive sleep apnea and 14 age- and body mass index-matched healthy male controls took part in the study as a control group. All subjects underwent echocardiographic examination; left ventricular cavity dimension, standard and tissue Doppler parameters, and aortic diameter (3 cm above aortic valve) at systole and diastole were measured. While the aortic stiffness index in patients with obstructive sleep apnea was significantly higher than that of the control group (4.5 ± 0.3 vs 2.1 ± 0.1, P = 0.001), the aortic distensibility index was found to be lower in this group compared with controls (2.4 ± 1.2 vs 3.9 ± 1.5 cm² dynes⁻¹ 10⁻⁶, P = 0.009). Furthermore, peak velocity of myocardial systolic wave and peak velocities of myocardial diastolic waves in sleep apnea patients were lower than in controls. There was an association between aortic stiffness and the apnea hypopnea index (coefficient = 0.49, P = 0.002). We also found an inverse correlation between peak velocity of myocardial diastolic wave and aortic stiffness (coefficient = −0.43, P = 0.003), using multiple linear regression. Increased aortic stiffness that is associated with the severity of disease in patients with obstructive sleep apnea may lead to diastolic dysfunction of the left ventricle.     

阻塞性睡眠呼吸暂停综合征与认知功能损害

阻塞性睡眠呼吸暂停综合征(OSAS)患者认知功能的损害普遍存在,不同程度的影响了患者的生存质量。这个常见的OSAS合并症却经常被漏诊,使患者得不到及时的诊断和治疗。认知功能损害的机制主要与睡眠间歇低氧和睡眠结构紊乱有关,间歇低氧引发的炎症和氧化应激反应对认知功能相关部位的中枢神经损伤是认知功能障碍的解剖学基础。充分治疗OSAS对认知功能的改善有益,提倡对患者的早期诊断和治疗。     

Right ventricular geometry and mechanics in patients with obstructive sleep apnea living at high altitude

Purpose

Repetitive obstruction of larynx during sleep can lead to daytime pulmonary hypertension and alterations in right ventricular morphology and function in a small fraction of obstructive sleep apnea syndrome (OSAS) patients. Environmental effects, particularly high altitude, can modify the effects of OSAS on pulmonary circulation, since altitude-related hypoxia is related with pulmonary vasoconstriction. This potential interaction, however, was not investigated in previous studies.

Methods

A total of 41 newly diagnosed OSAS patients were included in this study after pre-enrolment screening. Two-dimensional, three-dimensional, and Doppler echocardiographic data were collected after polysomnographic verification of OSAS. Three-dimensional echocardiograms were analyzed to calculate right ventricular volumes, volume indices, and ejection fraction.

Results

Systolic pulmonary artery pressure (38.35?±?8.60 vs. 30.94?±?6.47 mmHg; p?=?0.002), pulmonary acceleration time (118.36?±?16.36 vs. 103.13?±?18.42 ms; p?=?0.001), right ventricle (RV) end-diastolic volume index (48.15?±?11.48 vs. 41.48?±?6.45 ml; p?=?0.009), and RV end-systolic volume index (26.50?±?8.11 vs. 22.15?±?3.85; p?=?0.01) were significantly higher in OSAS patients, with similar RV ejection fraction (EF) between groups. No significant differences were noted in other two-dimensional, Doppler or speckle-tracking strain, measurements. Both RVEF and pulmonary acceleration time were predictors of disease severity.

Conclusions

A greater degree of RV structural remodeling and higher systolic pulmonary pressure were observed in OSAS patients living at high altitude compared to healthy highlanders. The reversibility of these alterations with treatment remains to be studied.

     

Effect of obstructive sleep apnea on aortic elastic parameters: relationship to left ventricular mass and function.

BACKGROUND: Obstructive sleep apnea (OSA) syndrome has a critical association with cardiovascular mortality and morbidity. Aortic elastic parameters are important markers for left ventricular (LV) function and are deteriorated in cardiovascular disease. METHODS AND RESULTS: Aortic elastic parameters and LV functions and mass were investigated in 40 patients with OSA (apnea - hypopnea index (AHI) >or=5) (mean age 51.3 +/-9 years, 32 males) and 24 controls (AHI <5) (mean age 51.9+/-5.2 years, 19 males). All subjects underwent polysomnographic examination and recordings were obtained during sleep. They also underwent a complete echocardiographic examination and systolic and diastolic aortic measurements were noted from M-mode traces of the aortic root. There were no significant differences in the demographic data of the patients with OSA and the controls. Subjects with OSA demonstrated higher values of aortic stiffness (7.1+/-1.88 vs 6.42+/-1.56, p=0.0001), but lower distensibility (9.47+/-1.33 vs 11.8+/-3.36, p=0.0001) than the controls. LV ejection fraction was significantly lower in patients with OSA when compared with the control group (61.3+/-5.2% vs 65.9+/-8.4%, p=0.0001). LV diastolic parameters were also compared and were worse in the subjects with OSA than in the control subjects (mitral E/A: 0.91 +/-0.42 vs 1.35+/-0.66, p=0.001; Em/Am: 0.86+/-0.54 vs 1.23+/-0.59, p=0.021). Respiratory disturbance index had a positive correlation with aortic stiffness (r=0.63, p=0.0001 and negative correlation with distensibility (r=-0.41, p=0.001). CONCLUSION: Aortic elastic parameters are deteriorated in OSA, which has an extremely high association with cardiovascular disease. Increased aortic stiffness might be responsible for the LV systolic and diastolic deterioration in OSA syndrome.