[Obstructive sleep apnea and hypertension. Diagnostic procedure--exclusion of risk factors--nCPAP treatment]. / Obstruktive Schlafapnoe und Bluthochdruck. Diagnostisches Vorgehen--Ausschalten begünstigender Faktoren--nCPAP-Behandlung.

Obstructive sleep apnea is a common illness with an estimated prevalence of 3% in the adult population. At least 50% of patients with obstructive sleep apnea also have hypertension, while approximately 30% of hypertensives also suffer from obstructive sleep apnea. This high level of coincidence together with the results of recent epidemiological studies and the frequent observation that hypertension may reverse under effective treatment for obstructive sleep apnea strongly suggest that this sleep disorder is an independent causal factor in the development of hypertension. The present paper considers the association of sleep apnea and hypertension and the resulting diagnostic and therapeutic consequences.

[Modification of cardiopulmonary performance parameters in patients with obstructive sleep apnea treated with nCPAP therapy]. / Entwicklung kardiopulmonaler Leistungsparameter bei Patienten mit obstruktiver Schlafapnoe unter nCPAP-Therapie.

nCPAP influences cardiopulmonary hemodynamic function in patients with obstructive sleep apnea (OSA). It is known that systolic function of the right and left ventricle, systemic and pulmonary hypertension, arterial blood gases and lung function during the day may improve under this treatment. We prospectively followed 30 patients with severe OSA and determined diastolic left ventricular function (Doppler echocardiography), cardiovascular efficiency (steady state exercise stress testing); and individual assessment of performance (standardized psychometric questionnaire) before, and 2 weeks and 6 months after initiation of nCPAP treatment. The following results could be obtained (first value after 2 weeks, second value after 6 months): Doppler echocardiography: E/A rose by 9.3% (p < 0.05) and another 0.5% (n.s.). E/A integral increased by 13.8% (p < 0.01) and another 3.5% (n.s.). Deceleration period decreased by 22.7% (p < 0.01) and another 3.1% (n.s.). Steady state exercise stress testing: Maximum performance rose by 10% (p < 0.05) and another 17.5% (p < 0.01). Heart rate ratio 100 W/rest dropped by 13.5% (p < 0.001) and another 6.5% (p < 0.01), systolic blood pressure ratio 100 W/rest by 0.8% (n.s.) and another 14.9% (p < 0.001). Diastolic blood pressure ratio 100 W/rest did not change significantly. Questionnaire: Assessment of well-being increased by 44.5% (p < 0.05) and another 16.9% (n.s.). After an initial drop of 0.8% (n.s.), quality of life increased by 14.9% (p < 0.05). Assessment of performance rose by 21.7% (p < 0.05) and another 4.1% (n.s.). nCPAP therapy in patients with OSA improves diastolic function of the left ventricle, cardiovascular performance and individual assessment of performance.

[Obstructive sleep apnea in patients with coronary heart disease]. / Obstruktive Schlafapnoe bei Patienten mit koronarer Herzerkrankung.

Patients with obstructive sleep apnea have an increased cardiovascular morbidity and mortality, those with co-existent coronary artery disease being particularly at risk. The object of our study was to evaluate the prevalence of obstructive sleep apnea in patients with coronary artery disease. 153 patients (117 men, 36 women) with verified coronary artery disease were given a highly sensitive standardized questionnaire. The 59 patients with pathological results were then checked with a 6-channel non-laboratory monitoring system. 22.2% of all patients had a respiratory disturbance index (RDI) above 5/h. and 14.4% above 10/h. 13.3% had a pathological RDI and additionally suffered from excessive daytime sleepiness. Patients with coronary artery disease have a high prevalence of obstructive sleep apnea and should consequently be screened for this sleep-related breathing disorder.

Clinical significance of ventricular late potentials in patients with obstructive sleep apnoea.

Patients with obstructive sleep apnoea (OSA) have an increased cardiovascular mortality and probably also an increased incidence of sudden cardiac death. Thus the question arises whether ventricular late potentials can constitute markers for an increased electric vulnerability in these patients. Signal-averaged electrocardiograms were recorded in 64 patients (6 female, 58 male; mean age 53.2 y) with OSA (mean apnoea-hypopnoea index (AHI) 41.7 h-1 +/- 24.3 h-1). Furthermore, a continuous ambulatory electrocardiogram and gated radionuclide ventriculography were performed. Ventricular late potentials were recorded in 5 men out of 64 patients. Two of them had coronary artery disease (1 patient post-myocardial infarction), 2 hypertension, and 1 nocturnal hypertension. No correlation could be traced between left ventricular ejection fraction, severity and extent of ventricular premature beats, or severity of OSA and occurrence of ventricular late potentials. It was noticeable, however, that the patients with ventricular late potentials had severe OSA (mean AHI 50.2/h vs. 40.9/h). Although OSA may lead to structural myocardial changes that could be the basis for re-entrant circuits, ventricular late potentials were found in only 7.8% of these patients. The results of this study demonstrate that at present ventricular late potentials and signal-averaged electrocardiograms do not prove useful as screening methods for risk stratification of patients with OSA.

[Sleep disorders in patients with dialysis-dependent renal failure]. / Schlafstörungen bei Patienten mit dialysepflichtiger Niereninsuffizienz.

A questionnaire was performed in order to classify the prevalence of sleep disorders in patients with end-stage renal disease treated with hemodialysis. 69 patients (41 male, 28 female) with a median age of 57 years completed the questionnaire. 67% of these patients complained of sleep disorders. 31 patients (45%) had evidence of periodic leg movement syndrome, 22 patients (32%) of restless legs syndrome. 29 patients (42%) had difficulties in falling asleep, 27 patients (39%) in maintaining sleep and 17 (25%) experienced both. Snoring was found in 25 patients (36%), 13 patients (19%) seemed to have sleep apnea. These data show an increased prevalence of sleep disorders in patients with end-stage renal disease on hemodialysis treatment. We conclude that these patients should consequently be asked for sleep disorders, as a specific diagnostic and therapeutic regime could improve quality of life and life expectancy. Especially sleep apnea is a disease that has a high prevalence in this patient group and which can be treated successfully.

[Constancy of the nCPAP pressure values in the long-term monitoring of patients with obstructive sleep apnea]. / Konstanz der nCPAP-Druckwerte in der Langzeitüberwachung von Patienten mit obstruktiver Schlafapnoe.

A retrospective study was undertaken to discover how often mask pressures had to be adjusted over time in patients treated for sleep apnoea by continuous positive airway pressure (nCPAP). Data were analysed on 106 such patients (95 men, 11 women; mean age 55.6 [33-74] years). Their body-mass index was 31.5 +/- 5.5 kg/m2, the apnoea hypopnea index before adjustment 7.6 +/- 2.2 mbar. At the first control, after a median of 7.5 months, the pressure had to be adjusted in 55% of patients, by an average of 8.3 +/- 2.4 mbar (P < 0.001). At the second and third follow-ups (after 19.5 and 31.5 months, respectively), no further significant adjustment in mean pressure was necessary, while changes had to be made in 34.0% and 17.9%, respectively. Changes in body weight correlated with changes in pressure level (r = 0.4614 for difference between initial setting and first control; r = 0.6708 for first and second controls; r = 0.7013 for second and third controls). 61% of patients in whom mask pressure had to be altered had symptoms. Of those in whom the pressure had to be increased 82% had symptoms. Only 17% of patients requiring no change had symptoms. These findings indicate that patients on nCPAP must be monitored by polysomnography about 6 months after the initial setting, and further tests should be performed about a year apart. If body weight and feeling of well being are maintained, non-laboratory monitoring should be adequate.