Early myocardial functional alterations in patients with obstructive sleep apnea syndrome

Obstructive Sleep Apnea and Right Ventricular Remodeling: Do We Have All the Answers?

Obstructive sleep apnea (OSA) syndrome is a very important sleep-related breathing disorder related to increased cardiovascular and overall morbidity and mortality. It is associated with multisystemic target organ damage due to micro- and macrovascular changes, resulting in carotid and coronary atherosclerosis, increased arterial stiffness, retinal damage, microalbuminuria, and cardiac remodeling. The latter consists of left ventricular (LV) hypertrophy, as well as diastolic and systolic dysfunction. The increasing burden of evidence shows that OSA also induces right ventricular (RV) remodeling that is more difficult to diagnose, but may also contribute to cardiovascular morbidity and mortality in these patients. Conventional echocardiographic parameters for assessment of RV systolic and diastolic functions are often not sensitive enough to detect subclinical and subtle changes in the RV function. Data published over last decade showed that the RV function, particularly systolic, is impaired in OSA patients and related with its severity. However, the introduction of speckle tracking echocardiography and the particularly longitudinal strain enabled the earlier detection of functional and mechanical changes even when conventional echocardiographic parameters of RV systolic function remained unchanged. The 3D echocardiography provided the possibility to evaluate the entire RV, with its unique shape, and determine 3D RV ejection fraction, which is comparable with results obtained by cardiac magnetic resonance. The use of this modality also provided a new insight into RV systolic (dys)function in OSA patients. In addition to weight loss, which has been proven very helpful in OSA patients, the only approved therapeutic approach is continuous positive airway pressure (CPAP) therapy. It is very important to assess if this therapy induces any improvement in cardiac structure and function. Limited data on this topic show that RV longitudinal strain is a more sensitive parameter rather than other conventional RV indexes in the detection of improvement in RV systolic function and mechanics. The aim of this review article is to summarize the current understanding of RV structural, functional, and mechanical changes in patients with OSA. Furthermore, we sought to provide the current knowledge regarding the effect of CPAP therapy on RV reverse remodeling in OSA patients.

Obstructive sleep apnea and right ventricular function: A meta-analysis of speckle tracking echocardiographic studies

The authors investigated the association between obstructive sleep apnea (OSA) and right ventricular (RV) systolic dysfunction trough a meta‐analysis of echocardiographic studies providing data on RV mechanics as assessed by longitudinal strain (LS). A systematic search was conducted using PubMed, OVID‐MEDLINE, and Cochrane library databases to search English‐language review papers published from inception to March 31, 2022. Only studies reporting data on RV free‐wall or global LS in patients with OSA of different severity and non‐OSA controls were reviewed. Data of interest were pooled to obtain standard means difference (SMD) with 95% confidence interval (CI). The meta‐analysis included 628 participants (436 with OSA and 192 controls) from eight studies. Compared to controls, RV free wall LS was significantly reduced in the pooled OSA group (SMD 1.02 ± .33, CI:.17/1.24, P < .002); this was also the case for RV global LS (SMD: .72 ± .11, CI: .50/.93, P < .0001). Notably, compared to patients with mild‐OSA those with moderate and severe OSA exhibited significantly lower RV free‐wall LS and global LS values; this was not the case for tricuspid annular plane excursion. In conclusions, both RV free‐wall and global LS are impaired in patients with OSA; deterioration of these indices, unlike TAPSE, was already evident in the early stages and was related to the severity of the syndrome. Thus, RV myocardial strain should be considered to be included in echocardiographic evaluation of OSA patients in order to detect subclinical cardiac damage in these patients regardless of its degree of severity.

Speckle tracking echocardiography in heart failure development and progression in patients with apneas

Obstructive (OA) and central apneas (CA) are highly prevalent breathing disorders that have a negative impact on cardiac structure and function; while OA promote the development of progressive cardiac alterations that can eventually lead to heart failure (HF), CA are more prevalent once HF ensues. Therefore, the early identification of the deleterious effects of apneas on cardiac function, and the possibility to detect an initial cardiac dysfunction in patients with apneas become relevant. Speckle tracking echocardiography (STE) imaging has become increasingly recognized as a method for the early detection of diastolic and systolic dysfunction, by the evaluation of left atrial and left and right ventricular global longitudinal strain, respectively. A growing body of evidence is available on the alterations of STE in OA, while very little is known with regard to CA. In this review, we discuss the current knowledge and gap of evidence concerning apnea-related STE alterations in the development and progression of HF.

Obstructive sleep apnea increases the risk of cardiovascular damage: a systematic review and meta-analysis of imaging studies

BACKGROUND

We aimed to perform a systematic review and meta-analysis of the association between obstructive sleep apnea (OSA) and cardiac as well as coronary impairment evaluated using imaging modalities. Finding of this study will provide more robust evidence regarding OSA-induced cardiovascular damage.

METHODS

We systematically searched through PubMed, EMBASE, and Cochrane library databases for relevant literatures on the association between OSA and cardiovascular damage evaluated using imaging modalities, and manually searched the references of selected articles for additional relevant articles. For each clinical parameter relevant to the meta-analysis, we first evaluated the methodological heterogeneity of the relevant studies and thereafter pooled the data together using fixed effect or random effect model. The difference in the relevant indices of cardiovascular damage between OSA patients and controls was evaluated using the standardized mean difference.

RESULTS

Of the 82 articles included in the final systematic analysis, 20 studies explored the association between OSA and coronary atherosclerosis. OSA patients had higher rate of coronary atherosclerosis assessed by coronary artery calcification score and plaque volume. Moreover, the severity of OSA and coronary atherosclerosis displayed a positive correlation. The rest of the studies (n = 62) evaluated cardiac alterations in OSA patients. According to the inclusion and exclusion criteria, 46 studies yielding 3082 OSA patients and 1774 controls were pooled for the meta-analysis. For left cardiac structure and function, OSA patients exhibited significantly wider left atrial diameter; higher left atrium volume index; wider left ventricular end-systolic diameter, left ventricular end-diastolic diameter, and left ventricular mass; higher left ventricular mass index; wider interventricular septum diameter and posterior wall diameter; and higher left ventricular myocardial performance index (all p < 0.05). In addition, compared with controls, left ventricular ejection fraction was significantly decreased in OSA patients (p = 0.001). For right cardiac structure and function, OSA patients displayed a significant increase in right ventricular diameter and right ventricular myocardial performance index (both p < 0.001). Finally, compared with controls, OSA patients displayed significant decrease in tricuspid annular plane systolic excursion and RV fractional area change (p = 0.001).

CONCLUSION

Overall, this systematic review and meta-analysis provides imaging evidence in support that OSA patients are at a higher risk of developing coronary atherosclerosis and display cardiac remodeling and dysfunction.

[Cardiac functional alterations and its risk factors in elderly patients with obstructive sleep apnea syndrome free of cardiovascular disease]

OBJECTIVE

To evaluate the changes of cardiac structure and function and their risk factors in elderly patients with obstructive sleep apnea syndrome (OSA) without cardiovascular complications.

METHODS

Eighty-two elderly OSA patients without cardiovascular disease admitted between January, 2015 and October, 2016 were enrolled in this study. According to their apnea-hypopnea index (AHI, calculated as the average number of episodes of apnoea and hypopnoea per hour of sleep), the patients were divided into mild OSA group (AHI < 15) and moderate to severe OSA group (AHI ≥ 15). The demographic data and the general clinical data were recorded and fasting blood samples were collected from the patients on the next morning following polysomnographic monitoring for blood cell analysis and biochemical examination. Echocardiography was performed within one week after overnight polysomnography, and the cardiac structure, cardiac function and biochemical indexes were compared between the two groups.

RESULTS

Compared with those with mild OSA group, the patients with moderate to severe OSA had significantly higher hematocrit (0.22±0.08 vs 0.17±0.04, P=0.032) and serum creatinine level (70.94± 27.88 vs 54.49±34.22 μmol/L, P=0.022). The left ventricular ejection fraction, interventricular septal thickness, left ventricular posterior wall thickness, left atrial diameter and left ventricular end-diastolic diameter were all similar between the two groups. With a similar early diastolic mitral flow velocity (E) between the two groups, the patients with moderate to severe OSA had a significantly higher late diastolic mitral flow velocity (A) (70.35±6.87 vs 64.09±8.31, P=0.0001) and a significantly lower E/A ratio (0.98±0.06 vs 1.08±0.05, P=0.0001) than the patients with mild OSA. Multiple linear regression showed that the E/A ratio was negatively correlated with AHI (β =- 0.645, P=0.0001).

CONCLUSIONS

Cardiac diastolic function impairment may occur in elderly patients with moderate or severe OSA who do not have hypertension or other cardiovascular diseases, and the severity of the impairment is positively correlated with AHI.

Evaluation of right ventricular performance and impact of continuous positive airway pressure therapy in patients with obstructive sleep apnea living at high altitude

Obstructive sleep apnea syndrome (OSAS) can lead to alterations in right ventricular (RV) performance and pulmonary vascular haemodynamics. Additionally, altitude-related hypoxia is associated with pulmonary vasoconstriction, and the effect of high-altitude on the pulmonary circulation in OSAS patients can be further altered. We sought to assess alterations in RV morphology and function in OSAS patients living at high altitude by way of 2-dimensional speckle tracking echocardiography (2D-STE), real-time 3- dimensional echocardiography (RT-3DE) and cardiac biomarkers. We also evaluate the impact of continuous positive airway pressure (CPAP) treatment on RV performance. Seventy-one patients with newly diagnosed OSAS and thirty-one controls were included in this study. All individuals were assessed for cardiac biomarkers as well as underwent 2D-STE and RT-3DE. Forty-five OSAS patients underwent CPAP therapy for at least 24 weeks and were studied before and after CPAP treatment. RT-3DE was used to measure RV volume, and calculate RV 3D ejection fraction (3D RVEF). Peak systolic strain was determined. Cardiac biomarkers, including C-reactive protein (CRP), N-terminal pro-B-type natriuretic peptide, and cardiac troponin T were also measured. Right atrium volume index, RV volume, RV volume index, systolic pulmonary artery pressure (sPAP), pulmonary vascular resistance (PVR) and level of serum CRP were significantly higher in OSAS group, while OSAS patients showed lower 3D RVEF and RV longitudinal strains. Compared to the patients with sPAP < 40 mmHg, RV longitudinal strains in patients with sPAP ≥ 40 mmHg were lower. Both RV global longitudinal strain and sPAP were associated with apnea–hypopnea index. Patients treated with 6 months of CPAP therapy had significant improvement in RV geometry and performance. RV structural abnormalities and RV function impairments were observed in OSAS patients living at moderate high altitude compared to control highlanders. The reversibility of these changes after application of CPAP were further confirmed.

Risk of Obstructive Sleep Apnea and Echocardiographic Parameters

BACKGROUND

Obstructive sleep apnea (OSA) is a chronic progressive disorder with high mortality and morbidity rate, associated with cardiovascular diseases (CVD), especially heart failure (HF). The pathophysiological changes related to OSA can directly affect the diastolic function of the left ventricle.

OBJECTIVES

To assess the association of the risk of OSA, evaluated by the Berlin Questionnaire (BQ), and echocardiographic (ECHO) parameters related to diastolic dysfunction in individuals without HF assisted in primary care.

METHODS

A cross-sectional study that included 354 individuals (51% women) aged 45 years or older. All individuals selected were submitted to an evaluation that included the following procedures: consultation, filling out the BQ, clinical examination, laboratory examination and transthoracic Doppler echocardiography (TDE). Continuous data are presented as medians and interquartile intervals, and categoric variables in absolute and relative frequencies. The variables associated with risk of OSA and at the 0.05 level integrated the gamma regression models with a log link function. A value of p < 0.05 was considered an indicator of statistical significance. Exclusion criteria were presence of HF, to fill out the BQ and patients with hypertension and obesity not classified as high risk for OSA by other criteria. All individuals were evaluated on a single day with the following procedures: medical appointment, BQ, laboratory tests and ECHO.

RESULTS

Of the 354 individuals assessed, 63% were classified as having high risk for OSA. The patients with high risk for OSA present significantly abnormal diastolic function parameters. High risk for OSA confirmed positive and statistically significant association, after adjustments, with indicators of diastolic function, such as indexed left atrium volume LAV-i (p = 0.02); E'/A' (p < 0.01), A (p = 0.02), E/A (p < 0.01).

CONCLUSION

Our data show that patients at high risk for OSA present worsened diastolic function parameters measured by TDE.

Association Between Sleep Disordered Breathing and Left Ventricular Function: A Cross-Sectional Analysis of the ECHO-SOL Ancillary Study

BACKGROUND

Prior studies have found that sleep-disordered breathing (SDB) is common among those with left ventricular (LV) dysfunction and heart failure. Few epidemiological studies have examined this association, especially in US Hispanic/Latinos, who may be at elevated risk of SDB and heart failure.

METHODS

We examined associations between SDB and LV diastolic and systolic function using data from 1506 adults aged 18 to 64 years in the Hispanic Community Health Study/Study of Latinos ECHO-SOL Ancillary Study (2011-2014). Home sleep testing was used to measure the apnea-hypopnea index, a measure of SDB severity. Echocardiography was performed a median of 2.1 years later to quantify LV diastolic function, systolic function, and structure. Multivariable linear regression was used to model the association between apnea-hypopnea index and echocardiographic measures while accounting for the complex survey design, demographics, body mass, and time between sleep and echocardiographic measurements.

RESULTS

Each 10-unit increase in apnea-hypopnea index was associated with 0.2 (95% CI, 0.1-0.3) lower E', 0.3 (0.1-0.5) greater E/E' ratio, and 1.07-fold (1.03-1.11) higher prevalence of diastolic dysfunction as well as 1.3 (0.3-2.4) g/m2 greater LV mass index. These associations persisted after adjustment for hypertension and diabetes mellitus. In contrast, no association was identified between SDB severity and subclinical markers of LV systolic function.

CONCLUSIONS

Greater SDB severity was associated with LV hypertrophy and subclinical markers of LV diastolic dysfunction. These findings suggest SDB in Hispanic/Latino men and women may contribute to the burden of heart failure in this population.

Obstructive sleep apnea and cardiac mechanics: how strain could help us?

Obstructive sleep apnea (OSA) syndrome is the most common sleep-breathing disorder, which is associated with increase cardiovascular morbidity and mortality. OSA increases risk of resistant arterial hypertension, coronary artery disease, heart failure, pulmonary hypertension, and stroke. Studies showed the significant relationship between OSA and cardiac remodeling. The majority of investigations were focused on the left ventricle and its hypertrophy and function. Fewer studies investigated right ventricular structure and function revealing deteriorated diastolic and systolic function. Data regarding left and right ventricular mechanics in OSA patients are scarce and controversial. The results of the studies that were focused on the influence of continuous positive airway pressure and weight reduction on cardiac remodeling revealed favorable effect on left and right ventricular structure and function. Recently published analyses confirmed positive effect of treatment on cardiac mechanics. Deterioration of left and right ventricular mechanics occurs before functional and structural cardiac impairments in the cascade of cardiac remodeling and therefore the assessment of left and right ventricular strain may represent a cornerstone in detection of subtle cardiac changes that develop significantly before other, often irreversible, alterations. Considering the fact that left and right ventricular strains have important predictive value in wide range of cardiovascular diseases, one should consider the evaluation of left and right ventricular strains in the routine echocardiographic assessment at all stages of disease-from diagnosis, during follow-up and evaluation of therapeutic effects. The main aim of this review is to provide the current overview of cardiac mechanics in OSA patients before and after (during) therapy, as well as mechanisms that could be responsible for cardiac changes.

Right Ventricular Remodeling and Dysfunction in Obstructive Sleep Apnea: A Systematic Review of the Literature and Meta-Analysis

Background

Recent studies have reported that obstructive sleep apnea (OSA) patients present alterations in right ventricular (RV) structure and function. However, large randomized controlled trials evaluating the impact of OSA on the right ventricle are lacking.

Methods

A comprehensive electronic database (PubMed, Web of Science, and Google Scholar) and reference search up to October 30, 2016, was performed. A systematic review and meta-analysis were performed to assess RV structure and function in OSA patients based on conventional echocardiography and tissue Doppler imaging.

Results

Twenty-five studies with 1,503 OSA patients and 796 controls were included in this study. OSA patients exhibited an increase in RV internal diameter (weighted mean difference (WMD) (95% confidence intervals (CIs)) 2.49 (1.62 to 3.37); p = 0.000) and RV wall thickness (WMD (95% CIs) 0.82 (0.51 to 1.13); p = 0.000). Furthermore, OSA patients had a significantly elevated RV myocardial performance index (WMD (95% CI) 0.08 (0.06 to 0.10); p = 0.000), decreased RV S' (WMD (95% CI) −0.95 (−1.59 to −0.32); p = 0.003), tricuspid annular plane systolic excursion (WMD (95% CI) −1.76 (−2.73 to −0.78); p = 0.000), and RV fractional area change (WMD (95% CI) −3.16 (−5.60 to −0.73); p = 0.011).

Conclusion

OSA patients display RV dilatation, increased wall thickening, and altered RV function.

Obstructive sleep apnoea and right ventricular function: A combined assessment by speckle tracking and three-dimensional echocardiography

BACKGROUND

Little is known on right ventricular (RV) involvement in obstructive sleep apnoea (OSA). This study aimed at evaluating early RV dysfunction by standard and advanced echocardiography in OSA.

METHODS

Fifty-nine OSA patients without heart failure and 29 age-matched controls underwent standard, speckle tracking and real time 3D echocardiography of right ventricle. OSA patients performed lung function tests and overnight cardio-respiratory monitoring with evaluation of apnea-hypopnea index (AHI).

RESULTS

OSA had significantly higher body mass index and systolic blood pressure (BP) than controls. RV diameters and systolic pulmonary arterial pressure (sPAP) were significantly higher in OSA, in presence of comparable tricuspid annular plane systolic excursion (TAPSE). OSA showed marginally lower RV global longitudinal strain (GLS) (p<0.05) and RV lateral wall strain (RV LLS) (p=0.04). Three-dimensional RV ejection fraction did not differ between the two groups. By stratifying patients according to sPAP, 18 OSA patients with sPAP≥30mmHg had lower TAPSE (p<0.05), RV GLS and RV LLS (both p<0.001) than 37 patients with normal sPAP. By separate multivariate analyses, RV GLS and RV LLS were independently associated with sPAP (both p<0.0001), AHI (p=0.035 and p=0.015 respectively) and BMI (p<0.05 and p=0.034) but not with age and systolic BP in OSA.

CONCLUSIONS

A subclinical RV dysfunction is detectable by speckle tracking in OSA. The impairment of RV GLS and RV LLS is more prominent than that of TAPSE and is evident when RVEF is still normal. GLS is independently associated with sPAP and OSA severity.

Longitudinal ventricular systolic dysfunction in patients with very severe obstructive sleep apnea: A case control study using speckle tracking imaging

Objective

Obstructive sleep apnea (OSA) is a prevalent condition that is increasingly recognized to be associated with cardiovascular disease. We aimed to investigate the subclinical systolic ventricular dysfunction of patients with OSA using novel speckle tracking echocardiographic (STE) techniques.

Methods

This study included 31 patients of polysomnography proven very severe OSA [Apnea Hypopnea Index(AHI) >40] and an equal number of matched population with no OSA as controls. All the study participants underwent a detailed conventional and tissue Doppler strain echocardiogram in addition to STE.

Results

There was no significant difference in conventional ventricular systolic function parameters including left ventricular (LV) ejection fraction, and myocardial performance index of left ventricle. Diastolic function was significantly reduced in patients with OSA as compared to controls. There was no difference in global circumferential strain or time to its peak between the two groups. However global longitudinal LV strain (GLS) was significantly reduced in patients with OSA (p < 0.01). Similarly time to peak longitudinal strain was prolonged in the OSA group as compared to controls. Segmental analysis revealed that the longitudinal strain abnormalities were more pronounced in the apical and mid segments of LV. AHI remained the only significant predictor of GLS in these patients.

Conclusion

Very severe OSA is associated with significant diastolic dysfunction as well as early systolic abnormalities as evidenced by abnormal global longitudinal strain. Sleep apnea severity as measured by AHI was the only significant predictor of abnormal longitudinal strain in these patients.

Assessment of regional right ventricular systolic function in patients with obstructive sleep apnea syndrome using velocity vector imaging

Obstructive sleep apnea syndrome (OSAS) is the most common type of sleep disorder which is associated with a series of cardiovascular disorders, including right ventricular (RV) dysfunction. However, it is difficult to assess the RV function systematically using a conventional echocardiography because RV has a complex geometrical shape. A case-control study was performed to assess the regional right ventricular potential dysfunction in patients with OSAS using velocity vector imaging (VVI) from March 2014 to October 2015.Sixty-nine patients with OSAS were divided into 3 groups: mild, moderate, and severe according to the apnea-hypopnea index (AHI). A total of 31 cases of healthy subjects were enrolled as the control group. Digital images of apex 4-chamber views were acquired to measure the peak systolic velocity (V), strain (ST), and strain rate (STR) of right ventricular free wall (RVFW) basal, middle, and apical segments using VVI.The peak systolic velocity of RVFW basal segments in the mild OSAS group increased (t = 2.22, P = 0.049) and gradually reduced in the moderate and severe groups compared with the controls. The values of systolic ST and STR of apical segments decreased in the mild OSAS group compared with the normal control group (t = 3.30, P = 0.02; t = 3.75, P = 0.01, respectively), and decreased furthermore in the moderate and severe OSAS groups.The change in the right ventricular regional systolic function starts before the development of heart dysfunction and pulmonary hypertension. At the early stage of OSAS, the deformation decreases in the RVFW apical segment, and the peak systolic velocities increase in the RVFW basal segment. The VVI is a sensitive method which is expected to be a worthy technique for early clinical therapy in patients with OSAS.

Sleep Disordered Breathing: Hypertension and Cardiac Structure and Function

Obstructive sleep apnea (OSA) is a common form of sleep disordered breathing and has a relatively high prevalence in the general population. The frequency and severity of OSA is associated with age, male sex, and obesity, and OSA has been linked to cardiovascular complications and death. Importantly, OSA has a strong association with both prevalent and incidental hypertension and has a particularly high prevalence in patients with resistant hypertension. In these patients, CPAP and other OSA-directed treatments have been proposed as therapy to help control blood pressure (BP), especially in patients who have not attained optimal BP control despite maximum pharmacological therapy. OSA has also been associated with alterations in cardiac structure and function, although most studies are small and highly limited in study design. Existing data suggest an association between OSA greater left ventricle (LV) mass and hypertrophy that appears independent of confounders including hypertension and obesity. Although less clear and more controversial, OSA severity has been linked to LV systolic and diastolic function, pulmonary hypertension, and right ventricular hypertrophy. Further studies are needed to confirm the potential causal role of OSA in these observed associations with cardiac abnormalities.

Tissue Doppler Imaging predicts central sleep apnea in patients with chronic heart failure: data from the Daunia Registry

BACKGROUND

Tissue Doppler imaging (TDI) is used to improve risk stratification in patients with chronic heart failure (CHF). So far, few studies have used this method to investigate the characteristics of subjects with CHF and Cheyne-Stokes breathing (CSB). The aim of this study was therefore to evaluate whether TDI assessment may predict the presence of CSB in patients with CHF.

MATERIALS AND METHODS

A total of 41 consecutive patients with CHF enrolled in the Daunia Heart Failure Registry underwent echocardiography assessment and nocturnal polygraphy to evaluate the presence of sleep apnea and CSB. Conventional echocardiography and TDI parameters were calculated. We have also quantified by TDI a combined index (EAS index) of diastolic and systolic performance: E'/(A' × S').

RESULTS

Subjects with evidence of CSB (N = 8) were characterized by lower values of A' (5·03 ± 2·64 vs. 7·88 ± 2·64 cm/s, P < 0·01). A' and EAS index values were related to Cheyne-Stokes episode rates (r = -0·49 and 0·52, P < 0·05 and <0·01 respectively), EAS index values also with the number of episodes of central apnea (r = 0·39, P < 0·05). A' values predicted the presence of CSB at poly-somnography examination with an OR 0·62 (95% CI 0·40-0·96, P < 0·05) even after correction for age and gender.

CONCLUSIONS

Tissue Doppler imaging values (A') are associated with the presence of sleep apnea at nocturnal polygraphy.

Left ventricular diastolic dysfunction in obstructive sleep apnoea syndrome by an echocardiographic standardized approach: An observational study

BACKGROUND

The association between obstructive sleep apnoea syndrome (OSAS), left ventricular (LV) diastolic dysfunction and LV geometry remains controversial because of coexisting disorders.

AIMS

To evaluate LV diastolic dysfunction and its independent predictors in a real-life cohort of OSAS patients, by a standardized approach.

METHODS

We consecutively included 188 OSAS patients after an overnight polysomnography to undergo clinical evaluation, ambulatory blood pressure measurement and complete echocardiography, combining M-mode, two-dimensional Doppler and tissue Doppler imaging modes. Correlations between OSAS severity and clinical and echocardiographical variables were assessed, and logistic regression models were used to identify possible determining factors of LV diastolic dysfunction.

RESULTS

Most patients were hypertensive (n=148, 78.7%) and already receiving treatment by continuous positive airway pressure (n=158, 84.5%). The prevalence of LV hypertrophy, defined by LV mass index (LVMi) normalized by height (2.7), was 12.4%, with a significant correlation with hypertension (P=0.004). The apnoea-hypopnoea index was correlated with body mass index (P<0.0001), 24-hour systolic blood pressure (P=0.01) and LVMi normalized by height (2.7) (P=0.03). Diastolic function assessed by a global approach was impaired for 70 patients (37.2%) and none of the OSAS severity variables was a determining factor after multivariable analysis with adjustment for age and sex.

CONCLUSION

Diastolic dysfunction assessed by a standardized approach is common in OSAS and should be routinely evaluated; it is independently predicted by none of the respiratory severity variables.

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.

Mitral annular plane systolic excursion in the assessment of left ventricular diastolic dysfunction in obese adults

Objective:

Mitral annular plane systolic excursion (MAPSE) is a simple way to assess left ventricle (LV) function. MAPSE is also correlated to parameters, illustrating the close relation between systolic and diastolic function of LV. In this study, we evaluated whether MAPSE could help us in the determination the LV diastolic dysfunction (DD) in obese adults.

Methods:

Our study was a prospective cross-sectional study. Obese patients who were referred from the endocrinology clinic were enrolled into this study. The participants included 40 obese patients with early-stage DD (grade I and II) and 40 obese patients with normal diastolic function, with an equal number of males and females. The patients with DD were further divided into Obese DD+I, who had grade I DD, and Obese DD+II, who had grade II DD. Student t-test, Mann-Whitney U test, one-way analysis of variance, ROC curve analysis, and pairwise comparisons of the ROC curves were used for statistical analysis.

Results:

MAPSE was different in all groups, with the lowest value in the Obese DD+II group (p<0.001). E/Em ratio was also different among all groups and was highest in the Obese DD+II group (p<0.001). Furthermore, MAPSE was negatively correlated with E/Em ratio (r=-0.368, p=0.020). The optimal threshold point of MAPSE in the diagnosis of left ventricle diastolic dysfunction (LVDD) was ≥1.45 cm, with 92.5% sensitivity (95% CI 79.6-98.4) and 77.5% specificity (95% CI 61.5-89.2) in the ROC curve analysis. There was no difference in the pairwise comparisons of the ROC curves of MAPSE and E/Em ratio in the diagnosis of DD [area under the ROC curve 0.902 (0.033) vs. 0.927 (0.027); p=0.54].

Conclusion:

Consequently, we found significantly a close relationship between MAPSE with conventional echocardiographic parameters, especially with E/Em, in the detection of left ventricle diastolic dysfunction (LVDD) in obese adults with normal LV ejection fraction. We think that MAPSE is a simple, easily acquired and less time consuming measurement and may help us in the stratification of LVDD in obese adults.

Endocardial and epicardial deformations in cardiac amyloidosis and hypertrophic cardiomyopathy

BACKGROUND

The aim of the present study was to analyze epicardial (EPI) and endocardial (ENDO) strain (S) in patients with transthyretin-related cardiac amyloidosis (TTR-CA) and hypertrophic cardiomyopathy (HCM) using echocardiography (TTE) with 2-dimensional feature tracking imaging (FTI).

METHODS AND RESULTS

Thirty-three subjects (11 with HCM, 11 with TTR-CA, and 11 healthy subjects as controls) with a New York Heart Association functional class ≤ II underwent conventional TTE and FTI. TTE was used for the evaluation of left ventricle (LV) wall thickness, mass, systolic and diastolic function. FTI was used for the evaluation of EPI and ENDO longitudinal, and circumferential, and radial S. LV wall thickness and mass were higher in both TTR-CA and HCM in comparison with controls (P < 0.001), but ejection fraction (EF) was similar among patients with TTR-CA, HCM and controls (63 ± 6%, 64 ± 6%, 61 ± 5%, respectively). ENDO and EPI longitudinal and circumferential S and radial S were significantly lower in HCM and TTR-CA when compared with controls (P < 0.01). No differences in EPI and ENDO longitudinal S, ENDO circumferential S and radial S were found between TTR-CA and HCM groups, while EPI circumferential S was significantly lower in the TTRCA group (6 ± 3.3%) than in the HCM group (8.1 ± 4.3%; P < 0.0001).

CONCLUSIONS

Longitudinal, circumferential and radial LV deformations are impaired in patients with TTR-CA and HCM with a preserved EF. Impairment of EPI circumferential strain is greater in TTR-CA than in HCM.

Impact of obstructive sleep apnea on global myocardial performance in children assessed by tissue Doppler imaging

This study aimed to assess the impact of obstructive sleep apnea (OSA) due to adenotonsillar hypertrophy (ATH) on the global myocardial performance in children using tissue Doppler imaging (TDI) and to evaluate the reversibility of the disorder after adenotonsillectomy (AT). The study included 42 children with OSA due to ATH (mean age, 5 ± 3.14 years) as the study group and 45 age- and sex-matched healthy children (mean age, 5.2 ± 3.08 years) as the control group. Polysomnography and echocardiography were performed. Indexed left ventricular mass (LVMi), pulmonary artery systolic pressure, mean pulmonary artery pressure (mPAP), and pulmonary vascular resistance (PVR) were calculated by echocardiography. Tissue Doppler imaging was used to determine the left ventricular and right ventricular myocardial performance index (MPI) of patients and control subjects before and after AT. The patients were classified into mild OSA (apnea-hypopnea index [AHI] 1-5; n = 18)] and moderate to severe OSA (AHI >5; n = 24) according to polysomnography findings. All the children in the control group had an AHI less than 1. They were treated using AT, then reevaluated by polysomnography and echocardiographic examination 6 to 8 months after surgery. Results are described as mean ± standard deviation. The patients with OSA had higher pulmonary artery systolic pressure, mPAP, PVR, LVMi, and right ventricular diastolic diameter than the control subjects. The patients with moderate to severe OSA showed more prominent changes than the patients with mild OSA, but the latter still differed significantly from the control subjects. The TDI-derived right ventricular MPI and left ventricular MPI measurements of the patients with OSA were higher (mean, 0.40 ± 0.08 vs 0.28 ± 0.01; p < 0.001) than those of the control subjects and (0.45 ± 0.05 vs 0.32 ± 0.05; p < 0.001) and correlated well with AHI and mPAP. In addition, mPAP was significantly correlated with AHI. Postoperatively, relief of OSA was validated by polysomnography, and a repeat of the echocardiographic parameters showed no significant differences between the patients and the control subjects. Tissue Doppler imaging can detect the subtle, subclinical changes in cardiac performance that occur in OSA due to adenotonsillar hypertrophy. Such changes generally are reversible after surgical treatment.