Accumulated nocturnal hypoxemia predict arterial endothelial function in patients with sleep-disordered breathing with or without chronic heart failure.

ABTSRACT: Sleep-disordered breathing (SDB) is often accompanied with the chronic heart failure (CHF). Hypoxemia due to pulmonary congestion from CHF and concurrent SDB might synergistically impair endothelial function and worsen the prognosis. However, the main factors affecting deterioration of endothelial function are unknown and whether the influence of hypoxemia differs in SDB patients with and without CHF remains unclear. Fifty-three patients (CHF group, n = 23; non-CHF group, n = 30) underwent polysomnography to evaluate their SDB and flow-mediated vasodilation (FMD) measurements to assess arterial endothelial function. We examined the relationships between FMD and SDB-related parameters, including our original index of accumulated hypoxemia by SDB throughout one-night sleep: the time desaturation summation index (TDS), calculated as follows: (100% - averaged arterial oxygen saturation during sleep) × total sleep time. The mean age in the CHF and non-CHF groups was 59.0 ± 13.5 and 57.7 ± 11.4 years, respectively. Although the FMD in the 2 groups were not significantly different, well-known adverse factors for FMD such as serum lipid profiles, blood pressure levels, and conventional indices of SDB were worse in the non-CHF group. Only the TDS was not significantly different between 2 groups and associated with FMD as shown by the univariate analysis (CHF: p < 0.05, non-CHF: p < 0.01) and multivariate analysis (CHF: p < 0.05, non-CHF: p < 0.01). Accumulated hypoxemia (TDS) rather than the frequency of hypoxemia might more influence on the endothelial function irrespective of the cardiac state. Removal of accumulation of nocturnal hypoxemia might be a target for treatment equally in the patients with and without CHF.

Crossover comparison between CPAP and mandibular advancement device with adherence monitor about the effects on endothelial function, blood pressure and symptoms in patients with obstructive sleep apnea.

Mandibular advancement device (MAD) is an alternative therapeutic option for CPAP to treat obstructive sleep apnea (OSA). While MAD showed the better adherence, patients with over moderate OSA have been treated more frequently with CPAP despite increasing positive evidence on the cardiovascular outcome with MAD, even in severe patients. Thus, more information is needed regarding the cardiovascular and symptomatic outcome of MAD treatment objectively compared to CPAP. Forty-five supine-dependent OSA patients (apnea-hypopnea index 20-40/h) were randomized to either CPAP or MAD and treated for 8 weeks and switched to another for 8 weeks. The primary endpoint was improvement in the endothelial function, indexed by the flow-mediated dilatation (FMD), and the secondary endpoint was the sleep-time blood pressure (BP). The duration of MAD use was evaluated objectively by an implanted adherence monitor. Treatment efficacy was also evaluated by home sleep monitor and a questionnaire about the symptoms. The adherence was not significantly different (CPAP vs. MAD: 274.5 ± 108.9 min/night vs. 314.8 ± 127.0 min/night, p = 0.095). FMD and sleep-time mean BP were not markedly changed from the baseline with either approach (CPAP vs. MAD: FMD, + 0.47% ± 3.1% vs. + 0.85% ± 2.6%, p = 0.64; BP, - 1.5 ± 5.7 mmHg vs. - 1.2 ± 7.5 mmHg, p = 0.48), although sleepiness, nocturia, and sleep-related parameters were similarly improved and more patients preferred MAD. As MAD and CPAP showed similar effects on cardiovascular outcome and symptomatic relief even with a comparable length of usage, we might expect MAD as an alternative treatment option for CPAP in this range of OSA group.

Prevalence of Sleep Disordered Breathing among Patients with Nocturia at a Urology Clinic.

OBJECTIVE: We assessed the prevalence of sleep disordered breathing (SDB) and characteristics among patients who visited a urology clinic complaining of nocturia (URO group) and those who visited a sleep apnea (SA) clinic complaining of excessive daytime sleepiness (EDS) (SA group). Additionally, we evaluated the effects of continuous positive airway pressure (CPAP) therapy in the URO group patients with nocturia and SDB resistant to conventional therapy for nocturia. METHODS: Questionnaires were used to assess EDS, nocturia and lower urinary tract symptoms in 34 URO group patients and 49 age-matched SA group patients. We also compared these factors in the male patients in both groups and the male and female patients in the SA group. Significant SDB was diagnosed as a 3% oxygen desaturation index (3%ODI) on pulse oximeter of >5/h. The treatment response was analyzed in six URO group patients treated with CPAP after not responding to the conventional medical treatment. RESULTS: SDB was found in 91.8% of the SA group patients and 70.6% of the URO group patients. The level of EDS and lower urinary tract symptoms were similar in both groups. The SA group showed higher 3%ODI values, while the frequency of urination during bedtime was higher in the URO group. The frequency of nocturnal urination was reduced after CPAP in the subjects resistant to conventional therapy. CONCLUSION: SDB is as prevalent in patients who visit a urology clinic complaining of nocturia as in those who visit a sleep apnea clinic. Patients who complains of nocturia must be assessed for SDB before starting therapy for nocturia.

Shock following a cat scratch.

A 49-year-old man with fever, pain in both legs, purpuras and cyanosis was admitted to hospital. He was a heavy drinker, but did not have diabetes or other immunosuppressive disease. On admission, he was in shock, with haematological findings suggestive of disseminated intravascular coagulation, and liver and kidney failure. The presence of a scratch wound on his face caused by a cat, and linear, Gram-negative rods phagocytosed by polynuclear leucocytes on peripheral blood smear suggested Capnocytophaga canimorsus infection. On day 1, antibiotics (ampicillin/sulbactam) and catecholamines were initiated. The patient required haemodialysis three times per week for 3 weeks. His toes became necrotic but improved and amputation was not necessary. On day 52, he was discharged from hospital with only mild sensory impairment of the legs.

The importance of daily physical activity for improved exercise tolerance in heart failure patients with limited access to centre-based cardiac rehabilitation.

BACKGROUND: Supervised cardiac rehabilitation provided at dedicated centres ameliorates exercise intolerance in patients with chronic heart failure. OBJECTIVE: To correlate the amount of physical activity outside the hospital with improved exercise tolerance in patients with limited access to centre-based programs. METHODS: Forty patients (median age 69 years) with stable heart failure due to systolic left ventricular dysfunction participated in cardiac rehabilitation once per week for five months. Using a validated single-axial accelerometer, the number of steps and physical activity-related energy expenditures on nonrehabilitation days were determined. RESULTS: Median (interquartile range) peak oxygen consumption was increased from 14.4 mL/kg/min (range 12.9 mL/kg/min to 17.8 mL/kg/min) to 16.4 mL/kg/min (range 13.9 mL/kg/min to 19.1 mL/kg/min); P<0.0001, in association with a decreased slope of the minute ventilation to carbon dioxide production plot (34.2 [range 31.3 to 38.1] versus 32.7 [range 30.3 to 36.5]; P<0.0001). Changes in peak oxygen consumption were correlated with the daily number of steps (P<0.01) and physical activity-related energy expenditures (P<0.05). Furthermore, these changes were significantly correlated with total exercise time per day and time spent for light (≤3 metabolic equivalents) exercise, but not with time spent for moderate/vigorous (>3 metabolic equivalents) exercise. CONCLUSIONS: The number of steps and energy expenditures outside the hospital were correlated with improved exercise capacity. An accelerometer may be useful for guiding home-based cardiac rehabilitation.

The influence of renal insufficiency on sleep-disordered breathing in patients with symptomatic chronic heart failure.

BACKGROUND: Renal insufficiency, a common condition among patients with chronic heart failure, complicates the management of heart failure. However, the influence of renal insufficiency on sleep-disordered breathing (SDB) - another important comorbidity of heart failure - has not been well studied. METHODS: Seventy-nine patients (60 men and 19 women) with stable, symptomatic heart failure caused by left ventricular systolic dysfunction (left ventricular ejection fraction of less than 45%) were studied. RESULTS: Thirty-nine patients (49%) had SDB as defined by an apnea-hypopnea index (AHI) of five or greater: 15 patients were classified as having mild SDB (AHI of five or greater and less than 15), 10 patients as having moderate SDB (AHI of 15 or greater and less than 30) and 14 patients as having severe SDB (AHI of 30 or greater). The etiology of SDB was predominantly central. Plasma brain natriuretic peptide concentration in the severe SDB group was 587±377 pg/mL, which was significantly higher than those of the remaining three groups (P<0.05). On the other hand, estimated glomerular filtration rate (eGFR) was comparable between non-SDB and SDB groups. There was no statistically significant correlation between eGFR and AHI, or between eGFR and the number of central sleep apneas in the study patients. CONCLUSION: Higher plasma brain natriuretic peptide concentrations were associated with more severe SDB, whereas the level of eGFR was not correlated with the severity of SDB. The results suggest that renal dysfunction plays a relatively minor role in determining breathing abnormalities in chronic heart failure.

Six-month aerobic exercise training ameliorates central sleep apnea in patients with chronic heart failure.

BACKGROUND: Sleep-disordered breathing (SDB) is common in patients with heart failure and carries an independent risk for poor long-term prognosis. We aimed to study the effects of supervised, aerobic exercise training for 6 months on SDB in patients with chronic heart failure. METHODS AND RESULTS: We enrolled 18 patients having both systolic dysfunction (left ventricular ejection fraction <45%) and SDB (apnea-hypopnea index [AHI] >10). The exercise group comprised 10 patients who participated in our cardiac rehabilitation program for 6 months, and the remaining 8 patients served as control. AHI (median [interquartile range]) was unchanged in the control group patients at 6-month intervals (30.4 [19.9-36.3] versus 36.6 [8.6-39.4], NS). In contrast, AHI was significantly decreased in the exercise group from 24.9 [19.2-37.1] to 8.8 [5.3-10.1] (P < .01). In the exercise group, the numbers of central sleep apnea per night was significantly decreased (152 [124-244] versus 50 [24-67], P < .01) after exercise training, but those of obstructive apnea/hypopnea were unchanged (42 [7-94] versus 18 [7-54], NS). In addition, exercise training significantly increased peak oxygen consumption and decreased minute ventilation to carbon dioxide production slope (both P < .01). CONCLUSIONS: Six-month, aerobic exercise training increased exercise capacity and improved central sleep apnea in patients with chronic heart failure from systolic dysfunction.

Mitral annulus displacement measured by tissue-tracking method with Doppler-tissue images is a useful marker of the severity of heart failure.

OBJECTIVES: This study investigated whether the measurement of mitral annulus displacement by the tissue-tracking method with Doppler-tissue images can provide more accurate information on the severity of heart failure compared to conventional methods, such as left ventricular ejection fraction (LVEF). BACKGROUND: Impaired left ventricular function is an important predictor of poor prognosis. Although LVEF has been used to assess left ventricular function, such indicators do not necessarily correlate well to clinical variables such as New York Heart Association (NYHA) functional class or plasma brain natriuretic peptide (BNP) concentration. METHODS: In 90 subjects with or without various heart diseases, mitral annulus displacement was measured by the tissue-tracking method with Doppler-tissue images and the correlations evaluated with NYHA functional class, plasma BNP concentration, left ventricular mass index and Tei index. RESULTS: Mitral annulus displacement by the tissue-tracking method with Doppler-tissue images was well correlated with NYHA functional class and plasma BNP concentration. LVEF was also correlated with these clinical variables, but significantly more weakly. Furthermore, mitral annulus displacement by the tissue-tracking method with Doppler-tissue images was correlated with left ventricular mass index and Tei index, which indicate left ventricular systolic and diastolic function. CONCLUSIONS: The present study suggests that mitral annulus displacement measured by our technique is a useful and reliable method for assessing the severity of heart failure.

Radiofrequency catheter ablation of premature ventricular complexes from right ventricular outflow tract improves left ventricular dilation and clinical status in patients without structural heart disease.

OBJECTIVES: The present study evaluated clinical benefits of radiofrequency catheter ablation (RFA) for premature ventricular complexes from right ventricular outflow tract (RVOT-PVC) in patients without structural heart disease. BACKGROUND: It is unknown whether PVC causes left ventricular (LV) dilation, which is a well-recognized precursor of LV dysfunction and heart failure, and whether eliminating PVC by RFA produces clinical benefits in patients with RVOT-PVC. METHODS: Frequency of PVC per total heart beats by 24-h Holter monitoring, left ventricular ejection fraction (LVEF), left ventricular end-diastolic internal dimension (LVDd), mitral regurgitation (MR) by echocardiogram, cardiothoracic ratio (CTR) by chest radiogram, and New York Heart Association (NYHA) functional class of 40 patients with RVOT-PVC without structural heart disease were evaluated before and 6 to 12 months after RFA. RESULTS: Before RFA, a subgroup of patients with frequent (>20%) PVC demonstrated significantly enlarged LVDd and CTR, reduced LVEF, increased MR, and deteriorated NYHA functional class as compared to the subgroup with rare (<20%) PVC (54 +/- 1 mm vs. 45 +/- 1 mm, 52 +/- 2% vs. 46 +/- 1%, 66 +/- 2% vs. 73 +/- 2%, 1.2 +/- 0.2 degree vs. 0.4 +/- 0.1 degree, and 1.8 +/- 0.2 vs. 1.3 +/- 0.1, respectively; p < 0.05). Furthermore, ablating RVOT-PVC readily produced the improvement of all these abnormalities (47 +/- 1 mm, 41 +/- 1%, 72 +/- 2%, 0.3 +/- 0.1 degree, and 1.0 +/- 0.0, respectively; p < 0.05 compared with before RFA). CONCLUSIONS: These findings suggest that frequent (>20%) RVOT-PVC may be a possible cause of LV dysfunction and/or heart failure, and RFA produces clinical benefits in these patients.