Article

Microvascular endothelial function in obstructive sleep apnea: Impact of continuous positive airway pressure and mandibular advancement

Département de Pneumologie, CHU, 4 Rue Larrey, 49033 Angers Cedex, France.
Sleep Medicine (Impact Factor: 3.1). 08/2009; 10(7):746-52. DOI: 10.1016/j.sleep.2008.06.013
Source: PubMed

ABSTRACT Endothelial dysfunction has been proposed as a potential mechanism implicated in the pathogenesis of cardiovascular complications of obstructive sleep apnea syndrome (OSAS). This study aimed to evaluate the microvascular endothelial function (MVEV) in OSAS and the impact on MVEF of 2 months of treatment with continuous positive airway pressure (CPAP) and mandibular advancement device (MAD).
Microvascular reactivity was assessed using laser Doppler flowmetry combined with acetylcholine (Ach) and sodium nitroprusside (SNP) iontophoresis in 24 OSAS patients and 9 control patients. In 12 of the 24 OSAS patients, microvascular reactivity was reassessed after 2 months of CPAP and MAD using a randomized cross-over design.
Ach-induced vasodilation was significantly lower in OSAS patients than in matched controls and correlated negatively with apnea hypopnea index (r=-0.49, p<0.025) and nocturnal oxygen desaturations (r=-0.63, p<0.002). Ach-induced vasodilation increased significantly with both CPAP and MAD. The increase in Ach-induced vasodilation under OSAS treatment correlated with the decrease in nocturnal oxygen desaturations (r=0.48, p=0.016).
Our study shows an impairment of MVEF in OSAS related to OSAS severity. Both CPAP and MAD treatments were associated with an improvement in MVEF that could contribute to improve cardiovascular outcome in OSAS patients.

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    • "We only studied the iontophoresis of ACh, but other drugs like sodium nitroprussiate or insulin could have been tested to show whether the role of the ECR is similar from a drug to another enabling a possible standardization of microcirculatory study results. However, we have chosen to study ACh iontophoresis because (i) it is a simple way to assess the endothelial function, which is of interest in the cardiovascular field (Cracowski et al., 2006) and (ii) it is one of the most widely used drugs in the literature (Mahe et al., 2012c; Morris and Shore, 1996; Rossi et al., 2009; Rousseau et al., 2009; Trzepizur et al., 2009). "
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    ABSTRACT: Endothelial function can be assessed by acetylcholine (ACh) iontophoresis with single current application. The effect of inter-electrodes distance as well as electrical cutaneous resistance (ECR) on ACh dependent vasodilation have never been studied using single current application . The aims of this study are (i) to compare ACh-peak and ECR measured at different inter-electrodes distances, (ii) to assess the relationship between ACh-peak and ECR, (iii) to study the reproducibility of the ECR values. Fourteen healthy subjects were included. Using laser speckle contrast imaging, ACh-iontophoreses (0.1mA, 30s) were performed on the forearm at a 7-day interval with an inter-electrodes distance set at 5cm. Two other inter-electrodes distances were also evaluated: 10cm and 15cm. ECR was measured during each ACh-iontophoresis as well as the ACh-peak. No statistical difference was found between the ACh-peak values obtained at 5cm, 10cm and 15cm. ECRs were also not statistically different. An inverse relationship (r=-0.60) was found between the ACh-peak and ECR (p<0.05). The coefficient of variation of the inter-day reproducibility of the ECR values was 9.1% [6.5%-15.1%] with an intra-class-correlation coefficient of 0.93 [0.81-0.98]. Inter-electrodes distance ranging from 5cm to 15cm changes neither the ACh-peak value nor. ECR value. ECR impacts ACh-peak values.
    Microvascular Research 04/2014; 93. DOI:10.1016/j.mvr.2014.04.001 · 2.43 Impact Factor
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    • "We only studied the iontophoresis of ACh, but other drugs like sodium nitroprussiate or insulin could have been tested to show whether the role of the ECR is similar from a drug to another enabling a possible standardization of microcirculatory study results. However, we have chosen to study ACh iontophoresis because (i) it is a simple way to assess the endothelial function, which is of interest in the cardiovascular field (Cracowski et al., 2006) and (ii) it is one of the most widely used drugs in the literature (Mahe et al., 2012c; Morris and Shore, 1996; Rossi et al., 2009; Rousseau et al., 2009; Trzepizur et al., 2009). "
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    ABSTRACT: Objectives Endothelial function can be assessed by acetylcholine (ACh) iontophoresis with single current application. The effect of inter-electrodes distance as well as electrical cutaneous resistance (ECR) on ACh dependent vasodilation have never been studied using single current application . The aims of this study are (i) to compare ACh-peak and ECR measured at different inter-electrodes distances, (ii) to assess the relationship between ACh-peak and ECR, (iii) to study the reproducibility of the ECR values. Methods Fourteen healthy subjects were included. Using laser speckle contrast imaging, ACh-iontophoreses (0.1 mA, 30 s) were performed on the forearm at a 7-day interval with an inter-electrodes distance set at 5 cm. Two other inter-electrodes distances were also evaluated: 10 cm and 15 cm. ECR was measured during each ACh-iontophoresis as well as the ACh-peak. Results No statistical difference was found between the ACh-peak values obtained at 5 cm, 10 cm and 15 cm. ECRs were also not statistically different. An inverse relationship (r = − 0.60) was found between the ACh-peak and ECR (p < 0.05). The coefficient of variation of the inter-day reproducibility of the ECR values was 9.1% [6.5%-15.1%] with an intra-class-correlation coefficient of 0.93 [0.81-0.98]. Conclusion Inter-electrodes distance ranging from 5 cm to 15 cm changes neither the ACh-peak value nor. ECR value. ECR impacts ACh-peak values.
    Microvascular Research 01/2014; · 2.43 Impact Factor
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    • "In OSAS, endothelial dysfunction could be caused by both hypoxia-reoxygenation cycles and chronic sleep fragmentation produced by repetitive arousals. A causal relationship between OSAS and endothelial dysfunction was demonstrated by a study in which flowmediated dilation in the forearm was improved by CPAP treatment (Ip et al., 2004; Trzepizur et al., 2009). Levels of nitric oxide, a major vasodilator substance released by the endothelium, have been found to be decreased in OSAS patients, and these levels normalize with CPAP therapy (Haight & Djupesland, 2003). "
    Cardiovascular Risk Factors, 03/2012; , ISBN: 978-953-51-0240-3
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