Jörg Heitmann

Surgical maxillofacial treatment of obstructive sleep apnea.

&NA; Obstructive sleep apnea is the most common sleeprelated breathing disorder, with a surprisingly high prevalence. The treatment of choice is nasal continuous positive airway pressure (CPAP) ventilation during sleep, which has to be applied throughout the patients whole life. Because of various underlying pathomechanisms in patients with certain craniofacial disorders—narrow posterior airway space and maxillary‐mandibular deficiency— surgical therapy by craniofacial osteotomies seems possible. A series of 38 consecutive patients were treated by 10‐mm maxillomandibular advancement by retromolar sagittal split osteotomy and Le Fort I osteotomy, respectively. Obstructive sleep apnea syndrome was improved considerably in all patients; there was no significant difference compared to the results under nasal CPAP. In 37 of 38 patients, the postoperative apnea‐hypopnea index was reduced clearly to under 10 per hour, oxygen saturation rose, and sleep quality improved. This was achieved by maxillomandibular advancement of 10 mm without secondary refinements in all but 2 patients. In one patient, the apnea‐hypopnea index could only be reduced to 20 per hour, probably because of insufficient maxillary advancement. These results indicate that successful surgical treatment is possible in a high percentage of selected patients with certain craniofacial characteristics. In addition to cardiorespiratory polysomnography, there should be routine cephalometric evaluation of all patients. Maxillomandibular advancement should be offered as an alternative therapy to all patients with maxillary and/or mandibular deficiency or dolichofacial type in combination with narrow posterior airway space. (Plast. Reconstr. Surg. 99: 619, 1997.)

Electrophysiologic evaluation of sinus node function and atrioventricular conduction in patients with prolonged ventricular asystole during obstructive sleep apnea

In 15 patients with ventricular asystole of 8.5 +/- 3.5 seconds (range 5.0 to 16.8) occurring exclusively during obstructive sleep apnea, electrophysiologic study of sinus node function and atrioventricular conduction before and after administration of intravenous atropine (0.02 mg/kg) was performed. Electrophysiologic parameters of sinus node function were normal in 12 of 15 patients (80%) and atrioventricular (AV) nodal function was normal in 7 patients (47%). Almost all abnormal findings of sinus node function and AV nodal function were reversible by administration of atropine. The HisPurkinje system function was normal in 6 patients (40%). Prolonged HV intervals (57 to 73 ms) were found in 9 patients (60%). Intra- or infra-His block was not observed in any patient. In summary, electrophysiologic parameters of sinus node function and AV conduction were normal or only slightly abnormal in all 15 study patients, which suggests that prolonged ventricular asystole during obstructive sleep apnea is not due to fixed or anatomic disease of the sinus node or the AV conduction system.

Long-term follow-up after surgical treatment of obstructive sleep apnoea by maxillomandibular advancement

Obstructive sleep apnoea (OSA) is a common disorder with potentially serious consequences. If maxillary and mandibular deficiency, often in combination with a narrow posterior airway space is present, therapy of OSA by maxillomandibular osteotomy is possible. However, long-term follow-up of patients undergoing these procedures is lacking. We present the results of 15 OSA patients (1 female and 14 males), who underwent maxillomandibular advancement surgery with a follow-up of at least 2 yrs. Polysomnography was performed before surgery, after 6-12 weeks, and 1 and 2 yrs postoperatively. Mean apnoea/hypopnoea index (AHI) decreased from 51.4 events.h-1 before therapy to 5.0 events.h-1 6 weeks postoperatively, and was 8.5 events.h-1 after 2 yrs. Oxygen saturation significantly increased following surgery. After 2 yrs, the AHI was < 10 events.h-1 in 12 out of 15 subjects. No significant changes were found comparing the 6-12 weeks versus the 2 year follow-up data. The significant increase in stage 3/4 non-rapid eye movement (NREM) sleep and decrease in stage 1 NREM sleep, indicative of the restoration of normal physiological sleep structure, persisted in 14 of the 15 subjects 2 yrs postoperatively. Three patients, however, did not show satisfactory improvement 2 yrs postoperatively; two showed obstructive and one central respiratory events. This study demonstrates that maxillomandibular advancement is successful in a high percentage of patients carefully selected by cephalometric and polysomnographic investigation. Postoperative success has proved to be stable over a period of 2 yrs. Further preoperative evaluation seems necessary in patients with predominantly mixed or central apnoeas.

Sympathetic activity is reduced by nCPAP in hypertensive obstructive sleep apnoea patients.

There is increasing evidence that nasal continuous positive airway pressure (nCPAP) lowers blood pressure in obstructive sleep apnoea (OSA) patients, not only during sleep but also in the daytime. However, both the mechanisms of blood pressure reduction and the considerable differences in the magnitude of the effect in the studies presented to date are not fully understood. Therefore, the authors prospectively studied the effect of nCPAP on noradrenaline plasma levels (NApl), blood pressure and heart rate (HR) in 10 normotensive and eight hypertensive OSA patients before and after 41.6±16.9 days of nCPAP therapy. Polysomnography and invasive blood pressure were continuously monitored over 24 h in the supine position before and with nCPAP. NApl were analysed every 15 min. In hypertensives, nCPAP reduced NApl by 36±25%, lowered mean arterial blood pressure substantially (night-time: −8.89±14.09 mmHg; daytime: −7.94±10.47 mmHg) and decreased HR by 6.6±5.4 beats·min−1, whereas in normotensives there were only minor changes. The decrease in heart rate was associated with a decrease in mean arterial blood pressure and noradrenaline plasma levels, suggesting a causal effect of nasal continuous positive airway pressure therapy. This nasal continuous positive airway pressure effect occurs mainly in hypertensive obstructive sleep apnoea patients, whereas the effect is small in normotensives. This may explain, at least in part, some of the discrepant results in previous treatment studies.

Relations among hypoxemia, sleep stage, and bradyarrhythmia during obstructive sleep apnea

BACKGROUND Obesity, apneic hypoxemia, and rapid eye movement (REM) sleep are supposed to be the major causes for bradyarrhythmia in patients with obstructive sleep apnea. The aims of this study were to compare clinical findings and diagnoses in patients with obstructive sleep apnea with and without nocturnal bradyarrhythmia and to analyze the relations among hypoxemia, sleep stage, and bradyarrhythmia. METHODS During a 17-month period 239 patients were found to have sleep apnea in an ambulatory study. Patients with nocturnal bradyarrhythmia were hospitalized for 3 days and polysomnographies were performed over 2 successive nights. A Holter electrocardiogram was recorded for 48 hours. RESULTS Nocturnal episodes of bradyarrhythmia were identified in 17 (7%) of 239 patients. Body mass index (39 +/- 7 vs 31 +/- 5 kg/m(2)) and respiratory disturbance index (90 +/- 36 per hour vs 24 +/- 24 per hour) were significantly different (P <.01) between patients with (n = 17) and without bradyarrhythmia (n = 222). Bradyarrhythmia occurred significantly more often during REM than non-REM sleep (P <.01). There was a significant difference in end-apneic oxygen saturation in apnea/hypopnea episodes with and without bradyarrhythmia (71% +/- 9% vs 75% +/- 10%; P <.01). A linear relation between end-apneic oxygen saturation and number of sinus arrests and heart blocks could not be found. CONCLUSIONS Patients with apnea-associated bradyarrhythmia are more overweight than patients without bradyarrhythmia. The higher respiratory disturbance index measurements found in these patients may be caused by this difference. Bradyarrhythmia occurs predominantly during REM sleep and occurred independently from decrease in oxygen saturation; a threshold value as an upper limit could not be found.

Sleep fragmentation and daytime vigilance in patients with OSA treated by surgical maxillomandibular advancement compared to CPAP therapy

Impaired vigilance is a frequent daytime complaint of patients with obstructive sleep apnoea (OSA). To date, continuous positive airway pressure (CPAP) is a well established therapy for OSA. Nevertheless, in patients with certain craniofacial characteristics, maxillomandibular advancement osteotomy (MMO) is a promising surgical treatment. Twenty‐four male patients with OSA (pretreatment respiratory disturbance index (RDI) 59.3 SD±24.1 events/h) participated in this investigation. The mean age was 42.7±10.7 years and the mean body mass index was 26.7±2.9 kg/m2. According to cephalometric evaluation, all patients had a narrow posterior airway space, more or less due to severe maxillary and mandibular retrognathia. All patients except two were treated first with CPAP for at least 3 months and afterwards by MMO. Two patients only tolerated a CPAP trial for 2 nights. Polysomnographic investigation and daytime vigilance were assessed before therapy, with CPAP therapy and 3 months after surgical treatment. Patients’ reports of impaired daytime performance were confirmed by a pretreatment vigilance test using a 90‐min, four‐choice reaction‐time test. The test was repeated with effective CPAP therapy and postoperatively. Daytime vigilance was increased with CPAP and after surgical treatment in a similar manner. Respiratory and polysomnographic patterns clearly improved, both with CPAP and after surgery, and showed significant changes compared to the pretreatment investigation. The RDI decreased significantly, both with CPAP (5.3±6.0) and postoperatively (5.6±9.6 events/h). The percentages of non‐rapid eye movement Stage 1 (NREM 1) sleep showed a marked decrease (with CPAP 8.2±3.6% and after MMO 8.2±4.4% vs. 13.3±7.4% before treatment), whereas percentages of slow wave sleep increased significantly from 8.0±6.1% before therapy to 18.2±12.8 with CPAP and 14.4±7.3% after MMO. The number of awakenings per hour time in bed (TIB) was significantly reduced after surgery (2.8±1.3), compared to both preoperative investigation (baseline 4.2±2.0 and CPAP 3.4±1.5). Brief arousals per hour TIB were reduced to half with CPAP (19.3±20.0) and after MMO (19.7±13.6), compared to baseline (54.3±20.0). We conclude that the treatment of OSA by MMO in carefully selected cases has positive effects on sleep, respiration and daytime vigilance, which are comparable to CPAP therapy.

The effects of dihydropyridine and phenylalkylamine calcium antagonist classes on autonomic function in hypertension: The VAMPHYRE Study*

The aim of the present study was to compare the effects of a long-acting dihydropyridine (amlodipine) and a nondihydropyridine (verapamil) on autonomic function in patients with mild to moderate hypertension. A total of 145 patients with a diastolic blood pressure (BP) between 95 and 110 mm Hg received 8 weeks of verapamil sustained release (240 mg) and amlodipine (5 mg) in a prospective randomized, double blind, cross-over study, both after 4 weeks of placebo. The 24-h autonomic balance was measured by analysis of 24-h heart rate variability and short-term autonomic control of BP by baroreflex sensitivity measurements. Plasma norepinephrine was sampled at rest. Blood pressure was equally reduced from 153/100 mm Hg to 139/91 mm Hg with verapamil and 138/91 mm Hg with amlodipine, P = .50/.59. The low- to high-frequency ratio (LF/HF), reflecting sympathovagal balance, was higher with amlodipine than with verapamil (4.66 v 4.10; P = .001). Baroreflex function was improved by both treatments; however, baroreflex sensitivity (BRS) was significantly higher with verapamil than with amlodipine (8.47 v 8.06 msec/mm Hg; P = .01). Plasma norepinephrine (NE) level was higher with amlodipine than with verapamil (1.59 v 1.32 nmol/L; P < .0001). Amlodipine induces a shift in sympathovagal balance, as measured by heart rate variability indices and plasma NE, toward sympathetic predominance compared with vagal predominance with verapamil. Short-term autonomic control of BP, as assessed by BRS, is more effectively improved by verapamil than by amlodipine. These contrasting effects on autonomic function suggest that the nondihydropyridine calcium antagonist verapamil may have additional beneficial effects beyond lowering BP compared with the dihydropyridine amlodipine.

A Prospective Polysomnographic Study on the Evolution of Complex Sleep Apnoea

Complex sleep apnoea (CompSA) may be observed following continuous positive airway pressure (CPAP) treatment. In a prospective study, 675 obstructive sleep apnoea patients (mean age 55.9 yrs; 13.9% female) participated. Full-night polysomnography was performed at diagnosis, during the first night with stable CPAP and after 3 months of CPAP. 12.2% (82 out of 675 patients) had initial CompSA. 28 of those were lost to follow-up. Only 14 out of the remaining 54 patients continued to satisfy criteria for CompSA at follow-up. 16 out of 382 patients not initially diagnosed with CompSA exhibited novel CompSA after 3 months. 30 (6.9%) out of 436 patients had follow-up CompSA. Individuals with CompSA were 5 yrs older and 40% had coronary artery disease. At diagnosis, they had similar sleep quality but more central and mixed apnoeas. On the first CPAP night and at follow-up, sleep quality was impaired (more wakefulness after sleep onset) for patients with CompSA. Sleepiness was improved with CPAP, and was similar for patients with or without CompSA at diagnosis and follow-up. CompSA is not stable over time and is mainly observed in predisposed patients on nights with impaired sleep quality. It remains unclear to what extent sleep impairment is cause or effect of CompSA.

Does short‐term treatment with modafinil affect blood pressure in patients with obstructive sleep apnea?

To investigate the effects of modafinil, a central nonamphetamine awakening substance, on blood pressure and heart rate in hypersomnolent patients with obstructive sleep apnea.

Effect of CPAP therapy on daytime cardiovascular regulations in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) is a sleep disorder with a high prevalence that causes pathological changes in cardiovascular regulation during the night and also during daytime. We investigated whether the treatment of OSA at night by means of continuous positive airway pressure (CPAP) improves the daytime consequences. Twenty-eight patients with OSA, 18 with arterial hypertension, 10 with normal blood pressure, were investigated at baseline and with three months of CPAP treatment. Ten age and sex matched healthy control subjects were investigated for comparisons. We recorded a resting period with 20min quiet breathing and an exercise stress test during daytime with ECG and blood pressure (Portapres). The bicycle ergometry showed a significant reduction of the diastolic blood pressure at a work load of 50W and 100W (p<0.05 and p<0.01, respectively) and a decrease of the heart rate recovery time after the stress test (p<0.05). These results indicate a reduction of vascular resistance and sympathetic activity during daytime. The coupling analysis of the resting periods by means of symbolic coupling traces approach indicated an effect of the CPAP therapy on the baroreflex reaction in hypertensive patients where influences of the systolic blood pressure on the heart rate changed from pathological patterns to adaptive mechanisms of the normotensive patients (p<0.05).