Microvascular endothelial function in obstructive sleep apnea: Impact of continuous positive airway pressure and mandibular advancement
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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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; DOI:10.1016/j.mvr.2014.04.001 · 2.43 Impact Factor
- Cardiovascular Risk Factors, 03/2012; , ISBN: 978-953-51-0240-3
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ABSTRACT: Vascular endothelial dysfunction has been recognized as an essential feature of obstructive sleep apnea (OSA). This study was designed to examine the hypothesis that OSA may impair the coronary microcirculation in patients with ST-segment elevation myocardial infarction (STEMI). The present study included 100 patients with a first STEMI who underwent primary percutaneous coronary intervention (PCI) within 12h from onset. Coronary flow velocity at baseline and at maximum hyperemia was measured using a Doppler guidewire following PCI. Total ST-segment elevation was calculated at baseline and 30 min after PCI. All patients underwent polysomnography at 14 days to diagnose OSA. Coronary flow velocity reserve (CFVR) was used for quantitative analysis of myocardial tissue perfusion. Systolic retrograde flow (SRF) and ST-segment resolution (STR) <50% were used as an index of microvascular injury. Forty-eight patients presented with OSA. CFVR was comparable between the 2 groups. The incidence of SRF was higher in OSA patients than in the control patients (6% vs. 31%, P=0.005). Patients with OSA had a higher incidence of STR <50% (31% vs. 60%, P=0.003). Multiple logistic regression showed that OSA was an independent positive predictor of SRF and STR <50% (odds ratio=4.46, P=0.044; odds ratio=3.79, P=0.010). OSA may impair myocardial tissue perfusion following primary PCI.Circulation Journal 02/2011; 75(4):890-6. DOI:10.1253/circj.CJ-10-0768 · 3.69 Impact Factor