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.

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.

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.

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.

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.

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.

First experience of using new adaptive servo-ventilation device for Cheyne-Stokes respiration with central sleep apnea among Japanese patients with congestive heart failure: report of 4 clinical cases

BACKGROUND

Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) in congestive heart failure (CHF) is generally considered a poor prognostic indicator, but treatment of CSR-CSA using an adaptive servo-ventilation (ASV) device has been developed. This is the first evaluation of its use in the management of CSR-CSA in Japanese CHF patients.

METHODS AND RESULTS

Four CHF patients with CSR-CSA that was unresponsive to conventional positive airway pressure (CPAP) underwent 3 nights of polysomnography: baseline, CPAP or bi-level PAP, and on the ASV. The apnea - hypopnea index (AHI) and central-AHI (CAHI) were markedly improved on ASV (AHI 62.7+/-10.1 to 5.9+/-2.2 /h, p=0.0006, CAHI 54.5+/-6.7 to 5.6+/-2.3 /h, p=0.007). In addition, the sleep quality improved significantly on ASV, including arousal index (62.0+/-10.5 to 18.7 +/-6.2 /h, p=0.012), percentage of slow-wave sleep (2.6+/-2.6 to 19.4+/-4.8 %, p=0.042).

CONCLUSIONS

ASV markedly improved CSR-CSA in patients with CHF. It is a promising treatment for Japanese patients with CHF.

Adaptive servo-ventilation in cardiac function and neurohormonal status in patients with heart failure and central sleep apnea nonresponsive to continuous positive airway pressure

OBJECTIVES

The aim of this study was to investigate whether effective suppression of central sleep apnea (CSA) by adaptive servo-ventilation (ASV) improves underlying cardiac dysfunction among patients with heart failure (HF) in whom CSA was not effectively suppressed by continuous positive airway pressure (CPAP).

BACKGROUND

The presence of CSA in HF is associated with a poor prognosis, whereas CPAP treatment improves HF. However, in a large-scale trial, CPAP failed to improve survival, probably due to insufficient CSA suppression. Recently, ASV was reported as the most effective alternative to CSA suppression. However, the effects of sufficient CSA suppression by ASV on cardiac function are unknown.

METHODS

Patients with New York Heart Association class ≥II HF, left ventricular ejection fraction <50%, and CSA that was unsuppressed (defined as an apnea-hypopnea index ≥15) despite ≥3 months of CPAP were randomly assigned to receive ASV in either CPAP mode or ASV mode.

RESULTS

Of 23 patients enrolled, 12 were assigned to the ASV-mode group and 11 were assigned to the CPAP-mode group. Three months after randomization, the ASV mode was significantly more effective in suppressing the apnea-hypopnea index (from 25.0 ± 6.9 events/h to 2.0 ± 1.4 events/h; p < 0.001) compared to the CPAP mode. Compliance was signi-ficantly greater with the ASV mode than with the CPAP mode. Improvement in left ventricular ejection fraction was greater with the ASV mode (32.0 ± 7.9% to 37.8 ± 9.1%; p < 0.001) than with the CPAP mode.

CONCLUSIONS

Patients with HF and unsuppressed CSA despite receiving CPAP may receive additional benefit by having CPAP replaced with ASV. Additionally, effective suppression of CSA may improve cardiac function in HF patients.

Relationship between sodium intake and sleep apnea in patients with heart failure

OBJECTIVES

The purpose of this study was to test the hypothesis that severity of sleep apnea (SA), assessed by frequency of apneas and hypopneas per hour of sleep (apnea-hypopnea index [AHI]), is related to sodium intake in patients with heart failure (HF).

BACKGROUND

Dependent edema and overnight rostral fluid shift from the legs correlate with the AHI in patients with HF in whom excessive sodium intake can cause fluid retention.

METHODS

Sodium intake was estimated by food recordings in 54 HF patients who underwent overnight polysomnography.

RESULTS

Thirty-one of the 54 patients had SA, and their mean sodium intake was higher than that in those without SA (3.0 ± 1.2 g vs. 1.9 ± 0.8 g, p < 0.001). There was a significant correlation between the AHI and sodium intake (r = 0.522, p < 0.001). Multivariate analysis showed that the significant independent correlates of the AHI were sodium intake, male sex, and serum creatinine level.

CONCLUSIONS

These findings suggest that in patients with HF, sodium intake plays a role in the pathogenesis of SA.

Contrasting effects of lower body positive pressure on upper airways resistance and partial pressure of carbon dioxide in men with heart failure and obstructive or central sleep apnea

OBJECTIVES

This study sought to test the effects of rostral fluid displacement from the legs on transpharyngeal resistance (Rph), minute volume of ventilation (Vmin), and partial pressure of carbon dioxide (PCO2) in men with heart failure (HF) and either obstructive (OSA) or central sleep apnea (CSA).

BACKGROUND

Overnight rostral fluid shift relates to severity of OSA and CSA in men with HF. Rostral fluid displacement may facilitate OSA if it shifts into the neck and increases Rph, because pharyngeal obstruction causes OSA. Rostral fluid displacement may also facilitate CSA if it shifts into the lungs and induces reflex augmentation of ventilation and reduces PCO2, because a decrease in PCO2 below the apnea threshold causes CSA.

METHODS

Men with HF were divided into those with mainly OSA (obstructive-dominant, n = 18) and those with mainly CSA (central-dominant, n = 10). While patients were supine, antishock trousers were deflated (control) or inflated for 15 min (lower body positive pressure [LBPP]) in random order.

RESULTS

LBPP reduced leg fluid volume and increased neck circumference in both obstructive- and central-dominant groups. However, in contrast to the obstructive-dominant group in whom LBPP induced an increase in Rph, a decrease in Vmin, and an increase in PCO2, in the central-dominant group, LBPP induced a reduction in Rph, an increase in Vmin, and a reduction in PCO2.

CONCLUSIONS

These findings suggest mechanisms by which rostral fluid shift contributes to the pathogenesis of OSA and CSA in men with HF. Rostral fluid shift could facilitate OSA if it induces pharyngeal obstruction, but could also facilitate CSA if it augments ventilation and lowers PCO2.

Differing relationship of nocturnal fluid shifts to sleep apnea in men and women with heart failure

BACKGROUND

In men with heart failure, nocturnal rostral fluid shift is associated with an overnight increase in the neck circumference (NC) and with severity of obstructive sleep apnea. Because the prevalence of obstructive sleep apnea is lower in women than in men with heart failure, we hypothesized that less fluid would shift into the neck in association with less severe obstructive sleep apnea in women than in men with heart failure.

METHODS AND RESULTS

In 35 men and 30 women with heart failure, we assessed overnight changes in NC (ΔNC) and leg fluid volume before and after polysomnography. The severity of obstructive sleep apnea was assessed by the apnea-hypopnea index. Although the changes in leg fluid volume did not differ significantly between men and women (-131 ± 90 versus -180 ± 132 mL, P=0.081), in women, ΔNC was smaller (P<0.001) than in men. Furthermore, although in men, changes in leg fluid volume correlated inversely with ΔNC (r=-0.755, P<0.001) and apnea-hypopnea index (r=-0.765, P<0.001), it did not in women.

CONCLUSIONS

Despite no difference in overnight displacement of fluid from the legs compared with in men, in women, less of this fluid reached the neck, and unlike men, there was no relationship between changes in leg fluid volume and either ΔNC or apnea-hypopnea index. These findings suggest a differing relationship between overnight fluid shift from the legs and severity of obstructive sleep apnea in women than in men with heart failure.

Mortality risk of triglyceride levels in patients with coronary artery disease

OBJECTIVE

The association between triglyceride level and the risk of coronary artery disease (CAD) remains controversial. In particular, the prognostic significance of triglyceride levels in established CAD is unclear. We aimed to assess the relationship between triglyceride levels and long-term (>10 years) prognosis in a cohort of patients after complete coronary revascularisation.

DESIGN

Observational cohort study.

SETTING

Departments of cardiology and cardiovascular surgery in a university hospital.

PATIENTS

Consecutive patients who had undergone complete revascularisation between 1984 and 1992. All patients were categorised according to the quintiles of fasting triglyceride levels at baseline.

MAIN OUTCOME MEASURES

The risk of fasting triglyceride levels for all-cause and cardiac mortality was assessed by multivariable Cox proportional hazards regression analyses.

RESULTS

Data from 1836 eligible patients were assessed. There were 412 (22.4%) all-cause deaths and 131 (7.2%) cardiac deaths during a median follow-up of 10.5 years. Multivariable analyses including total and high-density lipoprotein cholesterol and other covariates revealed no significant differences in linear trends for all-cause mortality according to the quintiles of triglyceride (p for trend=0.711). However, the HR increased with the triglyceride levels in a significant and dose-dependent manner for cardiac mortality (p for trend=0.031). Multivariable analysis therefore showed a significant relationship between triglyceride levels, when treated as a natural logarithm-transformed continuous variable, and increased cardiac mortality (HR 1.51, p=0.044).

CONCLUSIONS

Elevated fasting triglyceride level is associated with increased risk of cardiac death after complete coronary revascularisation.

Prognostic value of the metabolic syndrome for long-term outcomes in patients undergoing percutaneous coronary intervention

BACKGROUND

The prevalence of metabolic syndrome (MS), regarded as an important risk factor for coronary artery disease, is growing. However, the relationship between MS and long-term outcomes after percutaneous coronary intervention (PCI) in the Japanese patient population remains unknown.

METHODS AND RESULTS

Seven-hundred and forty-eight consecutive patients who underwent PCI were assessed. Patients were categorized by the presence or absence of MS using the NCEP-ATPIII definition (for obesity, a body mass index >or=25 kg/m(2) was used). Kaplan-Meier estimation and Cox proportional hazards model were used for unadjusted and adjusted analyses for all cause mortality and cardiac events. The progress of 318 (42.5%) patients with MS and 430 (57.5%) patients without MS was analyzed. The mean follow-up was 12.0+/-3.6 years. Overall, there were 88 (11.8%) deaths from all causes, and there were no significant differences between the 2 groups. The occurrence of cardiac events was significantly higher in the MS group than that in the no MS group (25.5% vs 15.6%, hazard ratio 2.23; 95% confidence interval 1.59-3.11; p<0.001).

CONCLUSIONS

The presence of MS significantly increased the risks of subsequent cardiac events among patients who underwent PCI.

Probucol therapy improves long-term (>10-year) survival after complete revascularization: a propensity analysis

OBJECTIVE

Probucol has anti-atherosclerotic properties and has been shown to reduce post-angioplasty coronary restenosis. However, the effect of probucol therapy on long-term (>10 years) outcome following coronary revascularization is less well established. Accordingly, we sought to determine if probucol therapy at the time of complete coronary revascularization reduces mortality in patients with coronary artery disease (CAD).

METHODS

We collected data from 1694 consecutive patients who underwent complete revascularization (PCI and/or bypass surgery). Mortality data were compared between patients administered probucol and those not administered probucol at the time of revascularization. A propensity score (PS) was calculated to evaluate the effects of variables related to decisions regarding probucol administration. The association of probucol use and mortality was assessed using 3 Cox regression models, namely, conventional adjustment, covariate adjustment using PS, and matching patients in the probucol and no-probucol groups using PS.

RESULTS

In the pre-match patients, 231 patients were administered probucol (13.6%). During follow-up [10.2 (SD, 3.2) years], 352 patients died (including 113 patients who died of cardiac-related issues). Probucol use was associated with significant decrease in all-cause death (hazard ratio [HR], 0.65; P=0.036 [conventional adjustment model] and HR, 0.57; P=0.008 [PS adjusted model]). In post-match patients (N=450, 225 matched pair), the risk of all-cause mortality was significantly lower in the probucol group than in the no-probucol group (HR, 0.45; P=0.002).

CONCLUSION

In CAD patients who had undergone complete revascularization, probucol therapy was associated with a significantly reduced risk of all-cause mortality.

Pioglitazone attenuates neointimal thickening via suppression of the early inflammatory response in a porcine coronary after stenting

Enhanced early inflammatory response accelerated the neointimal hyperplasia after vascular injury. Pioglitazone has antiatherogenic property through the inhibition of inflammation. Thus, we hypothesized that pioglitazone might inhibit the early inflammatory response, resulting in reduced neointimal hyperplasia in porcine coronary stenting model. Pioglitazone (5mg/kg/day) or placebo was administered orally to 10 pigs (20 coronaries) in each, from 7 days before stenting until the time of euthanasia at 3 or 28 days after stenting. The coronary artery of the pigs was injured with an oversized bare metal stent. Early inflammatory cell infiltration on the vessel surface was evaluated by scanning electron microscopy and was significantly suppressed in pioglitazone-treated group comparing with the control (% of site occurring greater infiltration: 40.8% versus 60.9%; P=0.002). Immunohistochemistry revealed that activated NF-kappaB and MCP-1 expression in the vessel was of significantly less in the pioglitazone-treated group. On day 28, morphometric assessment of stent-section showed significant reduction of neointimal thickness in the pioglitazone-treated group comparing with the control (neointimal thickness: 386.5+/-78.2mm versus 591.7+/-238.6mm; P=0.0051), whereas there was no difference in the injury score between two groups. Pioglitazone inhibited neointimal hyperplasia after stenting through a reduction of early inflammatory response.

Impact of metabolic syndrome among patients with and without diabetes mellitus on long-term outcomes after percutaneous coronary intervention

Metabolic syndrome (MS) is highly prevalent and an established key risk factor for coronary artery disease, regardless of the presence or absence of diabetes mellitus (DM). Long-term follow-up studies have addressed the influence of MS with and without DM on the prognosis of patients undergoing percutaneous coronary intervention (PCI). We classified 748 consecutive patients who had undergone PCI into four groups as follows: neither DM nor MS, DM alone, MS alone, and both DM and MS. Post hoc analyses were conducted using prospectively collected clinical data. Multivariate Cox regression was used to evaluate the risk within each group for all-cause mortality and composite cardiac events (cardiac death, non-fatal acute coronary syndrome), adjusting for age, gender, body mass index, low-density lipoprotein (LDL) cholesterol level, hypertension, smoking, prior coronary artery bypass graft, presentation of acute coronary syndrome, left ventricular ejection fraction, multivessel disease, and procedural success. The progress of 321 (42.9%) patients with neither DM nor MS, 109 (14.6%) patients with DM alone, 129 (17.2%) patients with MS alone, and 189 (25.3%) patients with both DM and MS was followed up for a mean of 12.0+/-3.6 years. Patients with both DM and MS had significant risk for increased all-cause mortality (2.10 [1.19-3.70]). Patients with MS alone (2.14 [1.31-3.50]) and with both DM and MS (1.87 [1.18-2.96]) were at significant risk for increased cardiac events. In conclusion, the risk of cardiac events is significantly increased in patients with metabolic syndrome following PCI, irrespective of DM.

Influence of diabetes on >10-year outcomes after percutaneous coronary intervention

There are few reports showing the relationship between diabetes and the long-term outcome following percutaneous coronary intervention (PCI) in Asians. As well, the association between glycosylated hemoglobin (HbA1c) level and outcome remains controversial. In this analysis, 748 Japanese patients including 298 with diabetes (DM) and 450 without diabetes (non-DM) who underwent PCI from 1984 to 1992 were evaluated over the long term. The mean follow-up was 12.0 +/- 3.6 years. There were 47 (15.8%) total deaths in DM and 41 (9.1%) in non-DM [hazard ratio (HR) 1.71, 95% confidence interval (CI) 1.11-2.65, P = 0.013] and 28 (9.4%) cardiovascular deaths in DM and 19 (4.2%) in non-DM (HR 2.09, 95% CI 1.14-3.81, P = 0.016). Among DM, increased HbA1c was associated with both total (HR 1.25, 95% CI 1.03-1.53, P = 0.024) and cardiovascular (HR 1.30, 95% CI 1.00-1.69, P = 0.048) mortality. Even in Asians, DM showed an increased mortality following PCI. Among DM, increased HbA1c level was also associated with mortality.

Influence of rostral fluid shift on upper airway size and mucosal water content

STUDY OBJECTIVE

Fluid displacement from the legs during recumbency while in bed might narrow the upper airway (UA) in association with nuchal fluid accumulation that may contribute to the pathogenesis of obstructive sleep apnea (OSA). The aim of this study was to test the hypothesis that rostral fluid displacement from the legs causes a greater decrease in UA cross-sectional area (UA-XSA) and a greater increase in UA mucosal water content (UA-MWC) and internal jugular venous volume (IJVVol) in subjects with OSA than in those without OSA.

METHODS

Subjects underwent baseline assessment of leg fluid volume (LFV) measured by bio-electrical impedance, as well as UA-XSA and UA-MWC by magnetic resonance imaging. They were then randomly assigned to a 20-min period either with or without application of lower body positive pressure (LBPP) of 40 mm Hg, followed by a 15-min washout period, after which they crossed over to the other arm of the study. Measurements of LFV, UA-MWC, and UA-XSA were repeated after each arm of the study.

RESULTS

In 12 subjects without sleep apnea, UA-XSA increased and UA-MWC decreased significantly, whereas in 12 subjects with OSA, UA-XSA decreased and UA-MWC increased significantly in response to LBPP. The changes in UA-XSA and UA-MWC in response to LBPP differed significantly between the 2 groups (p = 0.006 and p < 0.001, respectively), despite similar changes in LFV and IJVVol.

CONCLUSIONS

Our results suggest that rostral fluid shift may contribute to the pathogenesis of OSA at least partly through narrowing of the UA due to transudation of fluid into the UA mucosa.

Efficacy of peroxisome proliferative activated receptor (PPAR)-alpha ligands, fenofibrate, on intimal hyperplasia and constrictive remodeling after coronary angioplasty in porcine models

Constrictive remodeling and intimal hyperplasia play a prominent role in restenosis after angioplasty. It has been reported that the severity of constrictive remodeling and intimal hyperplasia correlate with adventitial angiogenesis and inflammation. Experimental evidence indicates that inflammation participates in angiogenesis, and therefore inhibition of inflammation may impair neovascularization. We tested whether fenofibrate, peroxisome proliferative activated receptors (PPAR)-alpha specific ligand, inhibits the early inflammation, adventitial angiogenesis, constrictive remodeling and intimal hyperplasia after angioplasty using porcine coronary arteries. Fenofibrate was tested in vivo, in 30 coronary arteries of 10 pigs (1g/day, orally) and was compared to placebo. Quantitative intravascular ultrasound and histopathologic assessment showed that fenofibrate increased lumen (6.28 mm(2) versus 5.15 mm(2)), vessel area (7.34 mm(2) versus 6.69 mm(2)) and inhibited constrictive remodeling. Inflammatory cell infiltration was evaluated with scanning electron microscopy 3 days after angioplasty and was significantly decreased in the treated vessels compared to control. Adventitial angiogenesis 3 days after angioplasty was significantly reduced in the injured vessels derived from the fenofibrate treated group compared to placebo. In conclusion, pharmacological activation of PPAR-alpha inhibited constrictive remodeling and neointimal hyperplasia after angioplasty through inhibition of inflammation and adventitial neovascularization.

Long-term (11-year) statin therapy following percutaneous coronary intervention improves clinical outcome and is not associated with increased malignancy

BACKGROUND

Statins have been proven to reduce cardiac events and mortality. However, there are few studies dealing with the long-term efficacy of statin therapy following percutaneous coronary intervention (PCI).

METHODS

We collected data from 575 consecutive patients who underwent PCI between 1987 and 1992. The baseline data, mortality and incidence of cardiovascular events of patients given statins and those not given statins at the time of PCI were compared.

RESULTS

There were 243 patients in the statin group and 332 patients in the non-statin group. During follow-up (11.0+/-3.0 years), 68 patients died. At about 10 years, statin use was significantly associated with lower all-cause mortality (8.2% versus 14.5%, P=0.023) and cardiac death (2.5% versus 6.9%, P=0.017). After adjusting for variables, statin use was found to be an independent predictor of death from all causes (hazard ratio [HR] 0.54, 95% confidence interval [CI] 0.29-0.99, P=0.048) and cardiac death (HR 0.24, 95% CI 0.07-0.80, P=0.02).

CONCLUSION

Statin use at the time of PCI was associated with a significantly reduced risk of death from all causes and cardiac death. Furthermore, this study provides evidence of a clinical benefit at about 10 years of statin use in patients who underwent PCI.

Cardiac metastasis from lung adenocarcinoma causing atrioventricular block and left ventricular outflow tract obstruction

Cardiac metastasis from lung cancer is rarely diagnosed antemortem, as it usually causes no symptoms or signs. We report the case of a 56-year-old man with recurrent lung adenocarcinoma in whom developed a large mass in the ventricular septum, complete atrioventricular block, and obstruction of the left ventricular outflow tract.

Overnight Effects of Obstructive Sleep Apnea and Its Treatment on Stroke Volume in Patients With Heart Failure

BACKGROUND

We previously showed in heart failure (HF) patients that obstructive respiratory events during sleep and generation of negative intrathoracic pressure during Mueller manoeuvres, mimicking obstructive apneas, acutely reduced stroke volume (SV). We also showed that treating obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) increased left ventricular ejection fraction over a 1-month period. We therefore hypothesized that, in HF patients, those with OSA would have greater overnight declines in SV and cardiac output (CO) than in those without sleep apnea, and that therapy of OSA using CPAP would prevent these declines.

METHODS

We examined overnight percent change in SV and CO in 32 HF patients with and 28 without OSA using digital photoplethysmography. Among patients with OSA, we also examined changes in SV and CO during a CPAP titration study.

RESULTS

During the baseline polysomnogram SV and CO decreased more overnight in those with OSA than in those without sleep apnea (-12.6 ± 7.7% vs -3.2 ± 6.8%; P < 0.001 and -16.2 ± 9.9% vs -3.7 ± 8.3%; P < 0.001, respectively). Overnight changes in SV and CO correlated inversely with total apnea-hypopnea index (r = -0.551; P < 0.001 and r = -0.522; P < 0.001, respectively). In 21 patients with OSA, CPAP reduced the total apnea-hypopnea index from 37.7 ± 21.4 to 15.0 ± 16.0 (P < 0.001) in association with attenuation of the overnight reduction of SV (from -14.0 ± 7.9% to -3.4 ± 9.8%; P = 0.002) and CO (from -17.2 ± 9.0% to -9.7 ± 10.7%; P = 0.042).

CONCLUSIONS

In patients with HF, coexisting OSA causes overnight declines in SV and CO that are prevented through reversal of OSA by CPAP.