Obstructive sleep apnea and heart failure: pathophysiologic and therapeutic implications

Obstructive sleep apnea (OSA) exposes the cardiovascular system to intermittent hypoxia, oxidative stress, systemic inflammation, exaggerated negative intrathoracic pressure, sympathetic overactivation, and elevated blood pressure (BP). These can impair myocardial contractility and cause development and progression of heart failure (HF). Epidemiological studies have shown significant independent associations between OSA and HF. On the other hand, recent prospective observational studies reported a significant association between the presence of moderate to severe OSA and increased risk of mortality in patients with HF. In randomized trials, treating OSA with continuous positive airway pressure suppressed sympathetic activity, lowered BP, and improved myocardial systolic function in patients with HF. These data suggest the potential for treatment of OSA to improve clinical outcomes for patients with HF. However, large-scale randomized trials with sufficient statistical power will be needed to ascertain whether treatment of OSA will prevent development of, or reduce morbidity and mortality from HF.

Prognosis of patients with heart failure and obstructive sleep apnea treated with continuous positive airway pressure

BACKGROUND

Therapy with continuous positive airway pressure (CPAP) provides several benefits for patients with heart failure (HF) complicated by obstructive sleep apnea (OSA). However, the effect on the prognosis of such patients remains unknown.

AIMS

To determine whether CPAP therapy and compliance affects the prognosis of HF patients with OSA.

METHODS

We classified 88 patients with HF and moderate-to-severe OSA into a CPAP-treated group (n = 65) and an untreated group (n = 23), and then those treated with CPAP were further subclassified according to CPAP therapy compliance. The frequency of death and hospitalization was analyzed using multivariate analysis.

RESULTS

During a mean (+/- SD) period of 25.3 +/- 15.3 months, 44.3% of the patients died or were hospitalized. Multivariate analysis showed that the risk for death and hospitalization was increased in the untreated group (hazard ratio [HR], 2.03; 95% confidence interval [CI], 1.07 to 3.68; p = 0.030) and in less compliant CPAP-treated patients (HR, 4.02; 95% CI, 1.33 to 12.2; p = 0.014).

CONCLUSION

Therapy with CPAP significantly reduced the risk of death and hospitalization among patients with HF and OSA. However, reduced compliance with CPAP therapy was significantly associated with an increased risk of death and hospitalization.

Prevalence and prognostic impact of the coexistence of multiple frailty domains in elderly patients with heart failure: the FRAGILE-HF cohort study

AIMS

To describe the prevalence, overlap, and prognostic implications of physical and social frailties and cognitive dysfunction in hospitalized elderly patients with heart failure.

METHODS AND RESULTS

The FRAGILE-HF study was a prospective multicentre cohort study enrolling consecutive hospitalized patients with heart failure aged ≥65 years. The study objectives were to examine the prevalence, overlap, and prognostic implications of the coexistence of multiple frailty domains. Physical frailty, social frailty, and cognitive dysfunction were evaluated by the Fried phenotype model, Makizako's 5 items, and Mini-Cog, respectively. The primary study outcome was the combined endpoint of heart failure rehospitalization and all-cause death within 1 year. Among 1180 enrolled hospitalized patients (median age, 81 years; 57.4% male), physical frailty, social frailty, and cognitive dysfunction were identified in 56.1%, 66.4%, and 37.1% of the patients, respectively. The number of identified frailty domains was 0, 1, 2, and 3 in 13.5%, 31.4%, 36.9%, and 18.2% of the patients, respectively. During follow-up, the combined endpoint occurred in 383 patients. Adjusted hazard ratios for 1, 2, and 3 domains, with 0 domains as the reference, were 1.38 [95% confidence interval (CI) 0.89-2.13; P = 0.15], 1.60 (95% CI 1.04-2.46; P = 0.034), and 2.04 (95% CI 1.28-3.24; P = 0.003), respectively. Incorporating the number of frailty domains into the pre-existing risk model yielded a 22.0% (95% CI 0.087-0.352; P = 0.001) net reclassification improvement for the primary outcome.

CONCLUSIONS

The coexistence of multiple frailty domains is prevalent in hospitalized elderly patients with heart failure. Holistic assessment of multi-domain frailty provides additive value to known prognostic factors.

Effect of flow-triggered adaptive servo-ventilation compared with continuous positive airway pressure in patients with chronic heart failure with coexisting obstructive sleep apnea and Cheyne-Stokes respiration

BACKGROUND

In patients with chronic heart failure (CHF), the presence of sleep-disordered breathing, including either obstructive sleep apnea or Cheyne-Stokes respiration-central sleep apnea, is associated with a poor prognosis. A large-scale clinical trial showed that continuous positive airway pressure (CPAP) did not improve the prognosis of such patients with CHF, probably because of insufficient sleep-disordered breathing suppression. Recently, it was reported that adaptive servo-ventilation (ASV) can effectively treat sleep-disordered breathing. However, there are no specific data about the efficacy of flow-triggered ASV for cardiac function in patients with CHF with sleep-disordered breathing. The aim of this study was to compare the efficacy of flow-triggered ASV to CPAP in patients with CHF with coexisting obstructive sleep apnea and Cheyne-Stokes respiration-central sleep apnea.

METHODS AND RESULTS

Thirty-one patients with CHF, defined as left ventricular ejection fraction <50% and New York Heart Association class >or=II, with coexisting obstructive sleep apnea and Cheyne-Stokes respiration-central sleep apnea, were randomly assigned to either CPAP or flow-triggered ASV. The suppression of respiratory events, changes in cardiac function, and compliance with the devices during the 3-month study period were compared. Although both devices decreased respiratory events, ASV more effectively suppressed respiratory events (DeltaAHI [apnea-hypopnea index], -35.4+/-19.5 with ASV; -23.2+/-12.0 with CPAP, P<0.05). Compliance was significantly greater with ASV than with CPAP (5.2+/-0.9 versus 4.4+/-1.1 h/night, P<0.05). The improvements in quality-of-life and left ventricular ejection fraction were greater in the ASV group (DeltaLVEF [left ventricular ejection fraction], +9.1+/-4.7% versus +1.9+/-10.9%).

CONCLUSIONS

These results suggest that patients with coexisting obstructive sleep apnea and Cheyne-Stokes respiration-central sleep apnea may receive greater benefit from treatment with ASV than with CPAP.

Determination of physiological plasma pentraxin 3 (PTX3) levels in healthy populations

BACKGROUND

The aim of this study was to evaluate the distribution of pentraxin 3 (PTX3) values in healthy subjects and to characterize its relationship with gender, age, body mass index (BMI), lipid profile, and blood sugar levels.

METHODS

A Japanese population of 1749 healthy subjects (818 men and 931 women) with a mean (SD) age of 59.6 (11.4) years (range 37-87 years) were examined.

RESULTS

Plasma PTX3 levels (PTX3 data are expressed as the geometric mean and confidence intervals) were i) significantly lower in men than in women (1.87 [1.81, 1.94] ng/mL vs. 2.12 [2.05, 2.19] ng/mL, p<0.0001), ii) significantly higher in the high age group (men, lowest quartile 1.62 [1.50, 1.74] ng/mL vs. highest quartile 2.14 [2.02, 2.27] ng/mL, p<0.001; women, lowest quartile 2.05 [1.92, 2.18] ng/mL vs. highest quartile 2.23 [2.02, 2.46] ng/mL, p<0.05), iii) inversely correlated with triglycerides (r=-0.19 in men and r=-0.18 in women, p<0.00001), and BMI (r=-0.16 in men and r=-0.24 in women, p<0.00001), and iv) lower in subjects with metabolic syndrome (MetS) than in the absence of MetS (1.82 [1.70, 1.95] ng/mL vs. 2.11 [2.06, 2.16] ng/mL, p=0.021).

CONCLUSIONS

We defined the normal range of plasma PTX3 in healthy Japanese subjects, and also showed the relationship between plasma PTX3 levels and established coronary risk factors, including MetS. PTX3 could be an ideal biomarker because it is a marker relatively independent from established coronary risk factors.

Rostral overnight fluid shift in end-stage renal disease: relationship with obstructive sleep apnea

BACKGROUND

In both healthy male subjects and men with heart failure, the severity of obstructive sleep apnea (OSA) is related to the amount of fluid displaced from their legs into the neck overnight. Whether overnight rostral fluid shift contributes to the pathogenesis of OSA in patients with end-stage renal disease (ESRD) is unknown. We hypothesized that the change in neck circumference (NC) and severity of OSA are related to the extent of overnight change in leg fluid volume (LFV) in patients with ESRD.

METHODS

We studied 26 patients with ESRD (14 men) on conventional hemodialysis. All subjects underwent polysomnography. LFV was measured by bioelectric impedance at bedtime and repeated in the next morning on awakening.

RESULTS

Our cohort's overall apnea-hypopnea index was 22.8±26.8 episodes/h of sleep. Their overnight change in LFV was -243±278 mL. The change in LFV correlated with apnea-hypopnea time (AHT) (P=0.001) and NC (P=0.0016). Other independent factors associated with AHT included age (P=0.005), baseline neck (P=0.0002), sitting time (P=0.008) and male gender. Stepwise multiple regression analysis revealed that age, change in LFV and male gender remained independent related to AHT.

CONCLUSIONS

Nocturnal rostral fluid shift is associated with the severity of OSA in ESRD. Prospective evaluation of the effect of reducing fluid overload and severity of OSA in ESRD patients warrants further examination.

Design of the effect of adaptive servo-ventilation on survival and cardiovascular hospital admissions in patients with heart failure and sleep apnoea: the ADVENT-HF trial

INTRODUCTION

Both types of sleep-disordered breathing (SDB), obstructive and central sleep apnoea (OSA and CSA, respectively), are common in patients with heart failure and reduced ejection fraction (HFrEF). In such patients, SDB is associated with increased cardiovascular morbidity and mortality but it remains uncertain whether treating SDB by adaptive servo-ventilation (ASV) in such patients reduces morbidity and mortality.

AIM

ADVENT-HF is designed to assess the effects of treating SDB with ASV on morbidity and mortality in patients with HFrEF.

METHODS

ADVENT-HF is a multicentre, multinational, randomized, parallel-group, open-label trial with blinded assessment of endpoints of standard medical therapy for HFrEF alone vs. with the addition of ASV in patients with HFrEF and SDB. Patients with a history of HFrEF undergo echocardiography and polysomnography. Those with a left ventricular ejection fraction ≤45% and SDB (apnoea-hypopnoea index ≥15) are eligible. SDB is stratified into OSA with ≥50% of events obstructive or CSA with >50% of events central. Those with OSA must not have excessive daytime sleepiness (Epworth score of ≤10). Patients are then randomized to receive or not receive ASV. The primary outcome is the composite of all-cause mortality, cardiovascular hospital admissions, new-onset atrial fibrillation requiring anti-coagulation but not hospitalization, and delivery of an appropriate discharge from an implantable cardioverter-defibrillator not resulting in hospitalization during a maximum follow-up time of 5 years.

CONCLUSION

The ADVENT-HF trial will help to determine whether treating SDB by ASV in patients with HFrEF improves morbidity and mortality.

Effect of intensified diuretic therapy on overnight rostral fluid shift and obstructive sleep apnoea in patients with uncontrolled hypertension

OBJECTIVES

Fluid displacement from the lower extremities to the upper body during sleep is strongly associated with obstructive sleep apnoea in hypertensive patients. The present pathophysiological study tests the hypothesis that intensified diuretic therapy will reduce the apnoea-hypopnoea index and blood pressure of uncontrolled hypertensive patients with obstructive sleep apnoea in proportion to the reduction in overnight change in leg fluid volume.

METHODS

Uncontrolled treated hypertensive patients underwent overnight polysomnography and measurement of overnight changes in leg fluid volume and neck circumference. Those with an apnoea-hypopnoea index at least 20 events per hour (n=16) received metolazone 2.5 mg and spironolactone 25 mg daily for 7 days after which the daily dose was doubled for 7 additional days. Baseline testing was again repeated.

RESULTS

Intensified diuretic therapy reduced the apnoea-hypopnoea index from 57.7 ± 33.0 to 48.5 ± 28.2 events per hour (P=0.005), overnight change in leg fluid volume from -418.1 ± 177.5 to -307.5 ± 161.9 ml (P<0.001) and overnight change in neck circumference from 1.2 ± 0.6 to 0.7 ± 0.4 cm (P<0.001). There was an inverse correlation between the reduction in overnight change in leg fluid volume and decrease in apnoea-hypopnoea index (r=-0.734, P=0.001). The reduction in overnight change in leg fluid volume was also significantly correlated with the change in morning blood pressure (r=0.708, P=0.002 for SBP; r=0.512, P=0.043 for DBP).

CONCLUSION

The findings provide further evidence that fluid redistribution from the legs to the neck during sleep contributes to the severity of obstructive sleep apnoea in hypertension and may be an important link between these two conditions.

Impact of sarcopenia on prognosis in patients with heart failure with reduced and preserved ejection fraction

AIMS

Sarcopenia, one of the extracardiac factors for reduced functional capacity and poor outcome in heart failure (HF), may act differently between HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF). We sought to investigate the impact of sarcopenia on mortality in HFpEF and HFrEF.

METHODS AND RESULTS

We performed a post hoc analysis of a multicentre prospective cohort study, including 942 consecutive older (age ≥65 years) hospitalized patients: 475 with HFpEF (ejection fraction ≥45%, age 81 ± 7 years, 48.8% men) and 467 with HFrEF (ejection fraction <45%, age 78 ± 8 years, 68.1% men). Sarcopenia was diagnosed according to the international criteria incorporating muscle strength (handgrip strength), physical performance (gait speed), and skeletal muscle mass (appendicular skeletal mass). The HFpEF group consisted of fewer patients with low appendicular skeletal muscle mass index measured using bioelectrical impedance analysis [<7.0 kg/m2 (men) and <5.7 (women); 22.1% vs. 31.0%, P = 0.003], and more patients with low handgrip strength [<26 kg (men) and <18 (women); 67.8% vs. 55.5%, P < 0.001], and slow gait speed [<0.8 m/s (both sexes); 54.5% vs. 41.1%, P < 0.001] than the HFrEF group, resulting in a similar sarcopenia prevalence in the two groups (18.1% vs. 21.6%, P = 0.191). Sarcopenia was an independent predictor of 1-year mortality in both HFpEF and HFrEF [hazard ratio (95% confidence interval) 2.42 (1.36-4.32), P = 0.003 in HFpEF and 2.02 (1.08-3.75), P = 0.027 in HFrEF; P for interaction = 0.666] after adjustment for other predictors.

CONCLUSIONS

In older patients with HF, sarcopenia contributes to mortality similarly in HFpEF and HFrEF.

Prognostic Impact of the Geriatric Nutritional Risk Index on Long-Term Outcomes in Patients Who Underwent Percutaneous Coronary Intervention

Malnutrition has been identified as an important predictor of poor clinical outcomes in patients with heart failure. The aim of this study is to examine the prognostic impact of nutritional status in patients with coronary artery disease (CAD) who underwent percutaneous coronary intervention (PCI). The impact of nutrition, assessed using the geriatric nutritional risk index (GNRI) calculated by serum albumin and body mass index, was evaluated in 2,853 patients with CAD who underwent their first PCI between 2000 and 2011. Patients were assigned to tertiles based on their GNRI levels. The incidences of all-cause death and cardiac death were assessed. The median GNRI values were 101 (interquartile range 95 to 106). Lower GNRI levels were associated with older age and higher prevalence of acute coronary syndrome and chronic kidney disease. During the median follow-up period of 7.4 years, Kaplan-Meier curves showed ongoing divergence in rates of mortality among tertiles (GNRI <98: 35.1%; 98 to 104: 20.6%; ≥104: 12.1%; log-rank p <0.0001). Stratification analysis by age also showed that the lowest GNRI tertile was associated with mortality in both patients <65 years and those ≥65 years. After adjusting for established cardiovascular risk factors, lower GNRI was an independent predictor of all-cause death (hazard ratio 1.55 per 10 decrease, 95% confidence interval 1.30 to 1.84, p <0.0001) and cardiac death (hazard ratio 1.44, 95% confidence interval 1.08 to 1.90, p = 0.01). In conclusion, nutritional status was associated with long-term clinical outcomes in CAD patients after PCI. Evaluation of GNRI carries important prognostic information and may guide the therapeutic approach to such patients.

Relationship of pharyngeal water content and jugular volume with severity of obstructive sleep apnea in renal failure

BACKGROUND

In patients with end-stage renal disease (ESRD), fluid overload may contribute to their high prevalence of obstructive sleep apnea (OSA) by increasing the amount of fluid displaced from the legs into the neck overnight, and possibly compressing the upper airway (UA). Indeed, in ESRD patients, the amount of overnight rostral fluid displacement from the legs is related to the frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index, AHI). We, therefore, hypothesized that in ESRD patients, the greater the UA-mucosal water content (UA-MWC) and internal jugular vein volume (IJVVol), the higher the AHI.

METHODS

We studied 20 patients with ESRD on thrice weekly hemodialysis who had undergone diagnostic polysomnography (age 41.0 ± 12.3 years, with a body mass index (BMI) of 25.8 ± 6.3 kg/m(2) and an AHI of 20.2 ± 26.8). The leg fluid volume (LFV) was measured by bioelectric impedance. The IJVVol and MWC were measured by UA magnetic resonance imaging (MRI).

RESULTS

The only significant independent correlates of the AHI were IJVVol (r = 0.801, P < 0.0001) and UA-MWC (r = 0.720, P = 0.0005) which together explained 72% of its variability.

CONCLUSIONS

These data suggest that fluid overload via increased IJVVol, and UA-MWC, contributes to the pathogenesis of OSA in patients with ESRD. These findings help us to explain the high prevalence of OSA in ESRD patients, and attenuation of OSA in association with nocturnal dialysis. They also suggest the need for randomized trials to determine whether more aggressive fluid removal in ESRD patients will alleviate OSA.

Hypothalamic Contribution to Pituitary Functions Is Recapitulated In Vitro Using 3D-Cultured Human iPS Cells

The pituitary is a major hormone center that secretes systemic hormones responding to hypothalamus-derived-releasing hormones. Previously, we reported the independent pituitary induction and hypothalamic differentiation of human embryonic stem cells (ESCs). Here, a functional hypothalamic-pituitary unit is generated using human induced pluripotent stem (iPS) cells in vitro. The adrenocorticotropic hormone (ACTH) secretion capacity of the induced pituitary reached a comparable level to that of adult mouse pituitary because of the simultaneous maturation with hypothalamic neurons within the same aggregates. Corticotropin-releasing hormone (CRH) from the hypothalamic area regulates ACTH cells similarly to our hypothalamic-pituitary axis. Our induced hypothalamic-pituitary units respond to environmental hypoglycemic condition in vitro, which mimics a life-threatening situation in vivo, through the CRH-ACTH pathway, and succeed in increasing ACTH secretion. Thus, we generated powerful hybrid organoids by recapitulating hypothalamic-pituitary development, showing autonomous maturation on the basis of interactions between developing tissues.

Differing effects of obstructive and central sleep apneas on stroke volume in patients with heart failure

RATIONALE

Obstructive sleep apnea and central sleep apnea increase risk of mortality in patients with heart failure (HF), possibly because of hemodynamic compromise during sleep. However, beat-to-beat stroke volume (SV) has not been assessed in response to obstructive and central events during sleep in patients with HF. Because obstructive events generate negative intrathoracic pressure that reduces left ventricular (LV) preload and increases afterload, but central events do not, obstructive events should lead to greater hemodynamic compromise than central events.

OBJECTIVES

To determine the effects of obstructive and central apneas and hypopneas during sleep on SV in patients with HF.

METHODS

Patients with systolic HF (LV ejection fraction ≤ 45%) and sleep apnea underwent beat-to-beat measurement of SV by digital photoplethysmography during polysomnography. Change in SV from before to the end of obstructive and central respiratory events was calculated and compared between these types of events.

MEASUREMENTS AND MAIN RESULTS

Changes in SV were assessed during 252 obstructive and 148 central respiratory events in 40 patients with HF. Whereas SV decreased by 6.8 (±8.7)% during obstructive events, it increased by 2.6 (±5.4)% during central events (P < 0.001 for difference). For obstructive events, reduction in SV was associated independently with LV ejection fraction, duration of respiratory events, and degree of oxygen desaturation.

CONCLUSIONS

In patients with HF, obstructive and central respiratory events have opposite hemodynamic effects: whereas obstructive sleep apnea appears to have an adverse effect on SV, central sleep apnea appears to have little or slightly positive effects on SV. These observations may have implications for therapeutic approaches to these two breathing disturbances.

Relationship between the prognostic nutritional index and long-term clinical outcomes in patients with stable coronary artery disease

BACKGROUND

Malnutrition has recently been reported to correlate with prognosis in patients with heart failure. However, the prognostic significance of nutritional status in patients with stable coronary artery disease (CAD) is unknown. The present study sought to examine the association between nutritional status assessed by the prognostic nutritional index (PNI) and cardiovascular outcomes in patients with stable CAD.

METHODS

A total of 1988 patients with stable CAD who underwent elective percutaneous coronary intervention (PCI) between 2000 and 2011 were examined. The PNI was calculated as 10×serum albumin (g/dL)+0.005×total lymphocyte count (per mm3). Patients were assigned to tertiles based on their PNI. The incidence of major adverse cardiac events (MACE), including all-cause death and non-fatal myocardial infarction, was evaluated.

RESULTS

The median PNI was 48.9 (interquartile range: 45.5-52.1). During the median follow-up of 7.5 years, Kaplan-Meier analysis showed that patients with lower PNI tertiles had higher rates of MACE (PNI <46.7: 35.5%; 46.7-50.8: 22.3%; >50.8: 16.0%; log-rank p<0.0001). After adjusting for other risk factors, the PNI was independently associated with MACE (hazard ratio 2.05 per 10 PNI decrease, 95% confidence interval: 1.66-2.54, p<0.0001). Adding the PNI to a baseline model with established risk factors improved the C-index (p=0.03), net reclassification improvement (p=0.03), and integrated discrimination improvement (p=0.0001).

CONCLUSIONS

The PNI was significantly associated with long-term cardiovascular outcomes in patients with stable CAD. Assessing PNI may be useful for risk stratification of CAD patients undergoing elective PCI.

Prognostic impact of nutritional status assessed by the Controlling Nutritional Status score in patients with stable coronary artery disease undergoing percutaneous coronary intervention

BACKGROUND

Recently, malnutrition has been shown to be related to worse clinical outcomes in patients with heart failure. However, the association between nutritional status and clinical outcomes in patients with coronary artery disease (CAD) remains unclear. We investigated the prognostic value of malnutrition assessed by the Controlling Nutritional Status (CONUT; range 0-12, higher = worse, consisting of serum albumin, cholesterol and lymphocytes) score in patients with CAD.

METHODS

The CONUT score was measured on admission in a total of 1987 patients with stable CAD who underwent elective percutaneous coronary intervention (PCI) between 2000 and 2011. Patients were divided into two groups according to their CONUT score (0-1 vs. ≥2). The incidence of major adverse cardiac events (MACE), including all-cause death and non-fatal myocardial infarction, was evaluated.

RESULTS

The median CONUT score was 1 (interquartile range 0-2). During the median follow-up of 7.4 years, 342 MACE occurred (17.2%). Kaplan-Meier curves revealed that patients with high CONUT scores had higher rates of MACE (log-rank p < 0.0001). High CONUT scores showed a significant increase in the incidence of MACE compared with low CONUT scores, even after adjusting for confounding factors (hazard ratio: 1.64, 95% confidence interval 1.30-2.07, p < 0.0001). Adding CONUT scores to a baseline model with established risk factors improved the C-index (p = 0.02), net reclassification improvement (p = 0.004) and integrated discrimination improvement (p = 0.0003).

CONCLUSIONS

Nutritional status assessed by the CONUT score was significantly associated with long-term clinical outcomes in patients with CAD. Pre-PCI assessment of the CONUT score may provide useful prognostic information.

Sleep apnea and heart failure

Sleep apnea is frequently observed in patients with heart failure (HF). In general, sleep apnea consists of two types: obstructive and central sleep apnea (OSA and CSA, respectively). OSA results from upper airway collapse, whereas CSA arises from reductions in central respiratory drive. In patients with OSA, blood pressure is frequently elevated as a result of sympathetic nervous system overactivation. The generation of exaggerated negative intrathoracic pressure during obstructive apneas further increases left ventricular (LV) afterload, reduces cardiac output, and may promote the progression of HF. Intermittent hypoxia and post-apneic reoxygenation cause vascular endothelial damage and possibly atherosclerosis and consequently coronary artery disease and ischemic cardiomyopathy. CSA is also characterized by apnea, hypoxia, and increased sympathetic nervous activity and, when present in HF, is associated with increased risk of death. In patients with HF, abolition of coexisting OSA by continuous positive airway pressure (CPAP) improves LV function and may contribute to the improvement of long-term outcomes. Although treatment options of CSA vary compared with OSA treatment, CPAP and other types of positive airway ventilation improve LV function and may be a promising adjunctive therapy for HF patients with CSA. Since HF remains one of the major causes of mortality in the industrialized countries, the significance of identifying and managing sleep apnea should be more emphasized to prevent the development or progression of HF.

The Impact of Empagliflozin on Obstructive Sleep Apnea and Cardiovascular and Renal Outcomes: An Exploratory Analysis of the EMPA-REG OUTCOME Trial

OBJECTIVE

To explore the effects of empagliflozin on the incidence of obstructive sleep apnea (OSA) and its effects on metabolic, cardiovascular (CV), and renal outcomes among participants with or without OSA in the EMPA-REG OUTCOME trial.

RESEARCH DESIGN AND METHODS

Participants with diabetes and CV disease were randomized to empagliflozin (10 and 25 mg) or placebo daily in addition to standard of care. OSA was assessed by investigator report using Medical Dictionary for Regulatory Activities version 18.0, and CV outcomes were independently adjudicated. Analyses were performed using multivariable-adjusted Cox regression models.

RESULTS

OSA was reported in 391 of 7,020 (5.6%) participants at baseline. Those with OSA were more likely to be male (83% vs. 71%) and to have moderate to severe obesity (BMI ≥35 kg/m2; 55% vs. 18%). Over a median of 3.1 years, empagliflozin had similar placebo-adjusted reductions in HbA1c, waist circumference, and systolic blood pressure, regardless of OSA status, but a larger effect on weight (adjusted mean ± SE difference at week 52: OSA vs. no OSA -2.9 ± 0.5 vs. -1.9 ± 0.1 kg). Incidence of 3-point major adverse CV events, CV death, heart failure hospitalization, and incident or worsening nephropathy in the placebo group was 1.2- to 2.0-fold higher for those with baseline OSA compared with those without. Empagliflozin significantly reduced the risk for outcomes regardless of OSA status (P-interaction all >0.05). Fifty patients reported a new diagnosis of OSA through 7 days after medication discontinuation, and this occurred less often with empagliflozin treatment (hazard ratio 0.48 [95% CI 0.27, 0.83]).

CONCLUSIONS

In EMPA-REG OUTCOME, participants with OSA had greater comorbidity and higher frequency of CV and renal events. Empagliflozin had favorable effects on risk factors and CV and renal outcomes regardless of preexisting OSA and may also reduce the risk for new-onset OSA.

Plasma pentraxin3 and arterial stiffness in men with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) induces inflammation and vascular damage that might contribute to an increased risk of cardiovascular disease (CVD). However, the mechanisms linking OSA and CVD are not fully understood. Pentraxin3 may play a significant role in vascular inflammation and damage. Currently, there is lack of data on pentraxin3 and its role in vascular damage associated with OSA.

METHODS

We enrolled 50 males with OSA and 25 controls matched for age and body mass index (BMI). Patients with OSA were further divided into mild and moderate to severe groups. We measured plasma pentraxin3 and evaluated vascular damage using an arterial stiffness parameter--the cardio-ankle vascular index (CAVI)--in all subjects. In the moderate to severe OSA group, pentraxin3 and CAVI were repeatedly measured following continuous positive airway pressure (CPAP) therapy for 1 month.

RESULTS

Pentraxin3 levels in the moderate-to-severe OSA group were significantly higher than those in the mild OSA and control groups, with median levels (25th-75th percentile) of 2.36 (1.79-2.78), 1.63 (1.15-2.05), and 1.53 (1.14-2.04) ng/ml, respectively (P < 0.01). Pentraxin3 level was independently correlated with CAVI (coefficient, 0.34 P < 0.01). In the moderate-to-severe OSA group, pentraxin3 and CAVI levels were significantly reduced (P < 0.01 and P = 0.04, respectively) after 1 month of CPAP therapy.

CONCLUSIONS

Plasma pentraxin3 and arterial stiffness levels in the moderate-to-severe OSA group were greater than the corresponding levels in patients without OSA. However, pentraxin3 level can be managed by CPAP therapy for OSA.

Efficacy of nasal bi-level positive airway pressure in congestive heart failure patients with cheyne-stokes respiration and central sleep apnea

BACKGROUND

Cheyne - Stokes respiration with central sleep apnea (CSR-CSA) contributes to the poor prognosis in patients with congestive heart failure (CHF). Bi-level positive airway pressure (bi-level PAP) may be an effective alternative for treating CSR-CSA and CHF.

METHODS AND RESULTS

Fourteen patients with CSR-CSA were divided into 2 groups, a control group that included 7 patients who decided to receive only conventional medications and a group of 7 patients that received bi-level PAP. Left ventricular ejection fraction (LVEF), mitral regurgitation (MR) area, plasma brain natriuretic peptide (BNP) concentration and the New York Heart Association (NYHA) functional class were evaluated initially (baseline) and 3 months later. In the control group, there were no significant changes in cardiac function during the study period. In contrast, in the group that received bi-level PAP, there were significant improvements in LVEF (from 36.3+/-2.9% to 46.0+/-4.0%, p = 0.02), MR area (from 30.4+/-7.6% to 20.0+/-5.1%, p = 0.02), BNP (from 993.6+/-332.0 pg/ml to 474.0+/-257.6 pg/ml, p = 0.02) and NYHA functional class (from 3.1+/-0.1 to 2.1+/-0.1, p = 0.03).

CONCLUSION

Treatment with bi-level PAP improved cardiac functions in CHF patients with CSR-CSA.

Impact of red blood cell distribution width on long-term mortality in diabetic patients after percutaneous coronary intervention

BACKGROUND

Red blood cell distribution width (RDW) is a novel prognostic marker that reflects oxidative stress and chronic inflammation in patients with cardiovascular disease. Diabetes mellitus increases oxidative stress and vascular inflammation, which accelerate atherosclerosis. However, the relationship between RDW and long-term outcome in diabetic patients with coronary artery disease (CAD) is unclear.

METHODS AND RESULTS

Subjects comprised 560 consecutive diabetic patients (mean age, 66.6 years; male, 80%) with stable CAD who had undergone elective percutaneous coronary intervention (PCI). Patients were divided into 2 groups according to median RDW at baseline (13.1%): a high RDW group (mean RDW, 14.0%; interquartile range, 13.3-14.2%); and a low RDW group (mean RDW, 12.6%; interquartile range, 12.4-12.9%). All-cause mortality rates were compared between groups. Mean duration of follow up was 3.9 years. Patients with high RDW were more likely to be older, show dyslipidemia and have a lower ejection fraction and decreased hemoglobin level. Twenty-nine patients (5.2%) died during follow up. The cumulative incidence of all-cause death was significantly higher in the high RDW group than in the low RDW group (log-rank P=0.0015). Multivariate analysis identified high RDW as being associated with all-cause mortality (hazard ratio, 2.56; 95% confidence interval, 1.12-6.62; P=0.025).

CONCLUSIONS

Increased RDW was significantly associated with increased long-term all-cause mortality in diabetic patients after PCI.

Inverse relationship of subjective daytime sleepiness to sympathetic activity in patients with heart failure and obstructive sleep apnea

BACKGROUND

Patients with heart failure (HF) and obstructive sleep apnea (OSA) are less sleepy than patients with OSA but without HF. Furthermore, unlike the non-HF population, in the HF population, the degree of daytime sleepiness is not related to the apnea-hypopnea index (AHI). The sympathetic nervous system plays a critical role in alertness. HF and OSA both increase sympathetic nervous system activity (SNA) during wakefulness. We hypothesized that in patients with HF and OSA, the degree of subjective daytime sleepiness would be inversely related to SNA.

METHODS

Daytime muscle SNA (MSNA) was recorded in patients with HF and OSA. Subjective daytime sleepiness was assessed by the Epworth Sleepiness Scale (ESS).

RESULTS

We studied 27 patients with HF and OSA and divided them into two groups based on the median ESS score: a less sleepy group, with an ESS score < 6 (n = 13), and a sleepier group, with an ESS score ≥ 6 (n = 14). The less sleepy group had higher MSNA than did the sleepier group (82.5 ± 9.9 bursts/100 cardiac cycles vs 69.3 ± 18.6 bursts/100 cardiac cycles; P = .037) and a longer sleep-onset latency (33 ± 29 min vs 14 ± 13 min; P = .039). The ESS score was inversely related to MSNA (r = -0.63; P < .001) but not to the AHI, arousal index, or indices of oxygen desaturation.

CONCLUSIONS

In patients with HF and OSA, the degree of subjective daytime sleepiness is inversely related to MSNA. This relationship is likely mediated via central adrenergic alerting mechanisms. These findings help to explain the previously reported lack of daytime hypersomnolence in patients with HF and OSA.

Relationship between advanced glycation end products and plaque progression in patients with acute coronary syndrome: the JAPAN-ACS sub-study

BACKGROUND

The Japan Assessment of Pitavastatin and Atorvastatin in Acute Coronary Syndrome (JAPAN-ACS) trial demonstrated that early aggressive statin therapy in patients with ACS significantly reduces plaque volume (PV). Advanced glycation end products (AGEs) and the receptors of AGEs (RAGE) may lead to angiopathy in diabetes mellitus (DM) and may affect on the development of coronary PV. The present sub-study of JAPAN-ACS investigates the association between AGEs and RAGE, and PV.

METHODS

Intravascular ultrasound (IVUS)-guided percutaneous coronary intervention (PCI) was undertaken, followed by the initiation of statin treatment (either 4 mg/day of pitavastatin or 20 mg/day of atorvastatin), in patients with ACS. In the 208 JAPAN-ACS subjects, PV using IVUS in non-culprit segment > 5 mm proximal or distal to the culprit lesion and, serum levels of AGEs and soluble RAGE (sRAGE) were measured at baseline and 8-12 months after PCI.

RESULTS

At baseline, no differences in the levels of either AGEs or sRAGE were found between patients with DM and those without DM. The levels of AGEs decreased significantly with statin therapy from 8.6 ± 2.2 to 8.0 ± 2.1 U/ml (p < 0.001), whereas the levels of sRAGE did not change. There were no significant correlations between changes in PV and the changes in levels of AGEs as well as sRAGE. However, high baseline AGEs levels were significantly associated with plaque progression (odds ratio, 1.21; 95% confidence interval, 1.01 - 1.48; p = 0.044) even after adjusting for DM in multivariate logistic regression models.

CONCLUSIONS

High baseline AGEs levels were associated with plaque progression in the JAPAN-ACS trial. This relationship was independent of DM. These findings suggest AGEs may be related to long-term glucose control and other oxidative stresses in ACS.

TRIAL REGISTRATION

NCT00242944.