肱动脉血流介导的血管舒张评价氯沙坦对高血压患者血管内皮功能的影响

目的:采用肱动脉血流介导的血管扩张(FMD)评价氯沙坦对高血压患者血管内皮功能的影响。方法:测定20例轻、中度原发性高血压患者肱动脉基础FMD及最大血流速度(Vmax)。予以口服氯沙坦50mg/d,8周后复查FMD及Vmax,同时观测血压变化。结果:口服氯沙坦8周后肱动脉血管内径无明显变化,而FMD由(4.64±3.72)％增大到(7.68±16.12)％,加压前Vmax、加压后Vmax较服药前增大,有统计学意义(P<0.05),且FMD的增大与血压降低并无相关性。结论:肱动脉FMD可以作为评价内皮依赖性血管扩张的有效方法;口服氯沙坦8周可以改善高血压患者血管内皮依赖性舒张功能,且这种改善与血压降低不相关。     

绝经后期超重女性循环内皮祖细胞数量和功能的变化及与内皮功能的关系

目的探讨绝经后期超重女性循环内皮祖细胞(EPC)数量和功能的变化及与肱动脉血流介导的内皮依赖性舒张功能(FMD)的关系。方法招募绝经后期体重正常女性20例,绝经后期超重女性20例,体重正常男性20例和超重男性20例,取外周血用流式细胞仪测定CD34和KDR双标阳性循环EPC水平,ac-LDL及lectin荧光标记方法评估体外培养的EPC数量,MTT法和Transwell小室评估EPC的增殖能力和迁移能力,内皮功能通过FMD测量。结果四组人群循环EPC数量差异无统计学意义(P0.05);与超重男性相比,绝经后期超重女性EPC功能及FMD差异无统计学意义(P0.05);与体重正常人群相比,超重人群FMD明显下降(P0.05),EPC的迁移和增殖能力明显减弱(P0.05)。循环EPC的迁移和增殖功能与FMD具有明显的相关性(r=0.45,P0.05;r=0.52,P0.05)。结论绝经后期超重女性FMD和循环EPC数量及功能没有得到保留,且明显减弱。     

80岁以上老老年高血压患者的动脉缓冲功能与内皮的调节功能

目的了解80岁以上老老年高血压患者的动脉缓冲功能和内皮调节功能变化. 方法采用高分辨率超声检测单纯收缩期高血压(ISH)和非单纯收缩期高血压(NISH,指收缩压与舒张压都升高)各10例患者在静息状态下的肱动脉横断面顺应性(CSC)、容积扩张性(VD),以及反应性充血时和舌下含服硝酸甘油后的内皮依赖性血管功能(FMD)和非内皮依赖性血管功能(NID),用于评估动脉的缓冲功能和内皮调节功能,并检测心脏功能.结果NISH组肱动脉横断面顺应性(CSC)、肱动脉容积扩张性(VD)均明显高于ISH组,差异有显著性(P=0.046,P＜0.01),而动脉硬化指数(β)则明显小于ISH组,差异有显著性(P＜0.01);在反应性充血状态下NISH组内皮依赖性血管舒张功能(FMD)亦明显高于ISH组(P=0.014).左室后壁收缩期厚度(LPWS)NISH组则明显小于ISH组(P=0.031).多因素分析结果FMD、β是与肱动脉容积扩张性(VD)关系最为密切的参数.结论两组患者动脉的缓冲功能和内皮调节功能均降低,同时ISH组患者动脉的缓冲功能和内皮调节功能明显低于NISH组患者.     

停用辛伐他汀对健康男性肱动脉内皮功能的影响

目的 观察停用辛伐他汀对Tc水平正常健康男性肱动脉内皮功能的影响.方法 16例健康青年男性服用20mg辛伐他汀4周后停药,分别检测停药前后不同时间点肱动脉内皮依赖性舒张功能(FMD),并测定血管活性物质--NO、血浆内皮素和6-酮-前列腺素F1α(6-keto-PGF1α)以及血脂参数的变化.结果 健康男性服用辛伐他汀4周后,在停药第1天观察到FMD较停药前明显降低,甚至低于未服药时的基线水平(P＜0.05).停药后血清NO水平较停药前和基础值亦明显降低,其变化与FMD的变化一致.停药后血浆内皮素水平升高,6-keto-PGF1α水平降低.血清LDL-C在停药后最初2d内无明显改变,其变化与FMD无明显相关.结论 健康男性服用辛伐他汀后突然停药,不仅使该药对肱动脉内皮功能的改善作用迅速消失,而且还对血管内皮功能造成进一步损害,该不良影响可能与循环中NO水平降低有关,是非TC依赖性的.     

缬沙坦对老年冠心病患者血管内皮功能的影响

目的探讨缬沙坦对老年冠心病患者血管内皮功能的影响。方法选取2016年3月—2017年4月新疆维吾尔自治区巴州人民医院神经内科收治的老年冠心病患者70例,采用随机数字表法分为对照组和观察组,每组35例,对照组患者给予阿司匹林联合美托洛尔治疗,观察组患者在对照组基础上加用缬沙坦治疗;两组患者均连续治疗两个月。比较两组患者治疗前后肱动脉基础内径、肱动脉内皮依赖性舒张功能(FMD)、血浆一氧化氮(NO)水平及血压。结果治疗前两组患者肱动脉基础内径、FMD、血浆NO水平比较,差异无统计学意义(P0.05);治疗后观察组患者FMD、血浆NO水平高于对照组(P0.05),而两组患者肱动脉基础内径比较,差异无统计学意义(P0.05)。两组患者治疗前后收缩压、舒张压比较,差异无统计学意义(P0.05)。结论缬沙坦能有效改善老年冠心病患者血管内皮功能,提高血浆NO水平,且其对内皮功能的改善并不依赖于降压作用。     

老年周围动脉闭塞性疾病内皮和非内皮依赖性舒张功能的无创研究

目的　探讨老年周围动脉闭塞性疾病 (peripheralarterialocclusivedisease,PAOD)内皮依赖性舒张功能 ,即血流介导的血管扩张功能 (flow mediateddilation ,FMD)和硝酸甘油介导的非内皮依赖性舒张功能 (nitroglycerin mediateddi lation,NMD)状况及其相关因素。方法　采用超声多普勒检测 33例已确诊为PAOD的老年患者肱动脉FMD及NMD ,并分别与 40例健康老年人及 30例具有心血管危险因素的老年非PAOD患者进行对照研究。结果　老年PAOD患者FMD及NMD均显著低于对照组 ;肱动脉基础内径、收缩压、低密度脂蛋白胆固醇与FMD呈负相关 ;FMD与NMD呈正相关 ,肱动脉基础内径与NMD呈负相关。结论　老年PAOD患者FMD及NMD均受损 ;肱动脉基础内径、收缩压、低密度脂蛋白胆固醇可能是FMD独立的预测因子 ;而FMD及肱动脉基础内径与NMD密切相关。     

老年原发性高血压患者肱动脉血流介导的内皮依赖性舒张功能变化

目的探讨老年原发性高血压患者肱动脉血流介导的内皮依赖性舒张功能(FMD)的变化。方法选择2008年2月至2011年6月诊断为原发性高血压的老年患者52例为观察组,同期门诊健康老年人30例为对照组,高分辨率超声测定肱动脉血流介导的内皮依赖性舒张功能(FMD)。结果高血压患者肱动脉血管基础内径、基础血流与健康人比较无显著性差异(P>0.05),FMD较健康人明显降低,存在显著性差异(P<0.05);NMD稍有升高,与健康人比较无显著性差异(P>0.05)。结论早期检测老年原发性高血压患者肱动脉血流介导的FMD的变化,可为病变提供证据并进行干预性治疗,对于高血压防治具有重要的临床意义。     

高分辨率超声技术评价病毒性心肌炎患者血管内皮功能的改变

目的:采用高分辨率超声技术探讨病毒性心肌炎患者血流介导的肱动脉舒张反应(FMD)和硝酸甘油介导的肱动脉舒张反应(NMD).方法:采用高分辨率超声技术检测30例病毒性心肌炎患者(心肌炎组)的内皮功能,并与20例非心肌炎患者(非心肌炎组)及20例健康体检者(正常对照组)做比较.结果:心肌炎组FMD(8.73±2.87)%和非心肌炎组FMD(13.00±2.79)%均低于正常对照组(19.32±2.67)%,且差异有统计学意义(P均＜0.01),心肌炎组FMD低于非心肌炎组,差异有统计学意义(P＜0.01).心肌炎组NMD(19.68±5.84)%、非心肌炎组NMD(23.18±4.28)%及正常对照组NMD(24.24±4.13)%3组比较差异无统计学意义(P＞0.05).结论:病毒性心肌炎患者血管内皮依赖性舒张功能受损明显,而非内皮依赖性舒张功能变化不明显.     

中国人群血管内皮功能与心血管危险因素的相关性

目的:探讨心血管危险因素与肱动脉血流介导的舒张功能(flow-mediated dilatation,FMD)在中国人群中的相关性。方法:选取2 511例年龄(46.86±9.52)岁的体检人群作为研究对象,采集研究对象的心血管危险因素(年龄、体质指数、腰围、血压、血脂、血肌酐、血尿酸、空腹血糖和吸烟情况)及病史(高血压、糖尿病、血脂异常和冠心病)信息。结果:多因素分析显示FMD与年龄(β=-0.29,P0.001),性别(β=-0.12,P0.001),体质指数(β=-0.12,P=0.001),腰围(β=-0.10,P=0.011),收缩压(β=-0.12,P0.001),空腹血糖(β=-0.04,P=0.009),总胆固醇(β=-0.04,P=0.014),吸烟(β=-0.05,P=0.003),肱动脉基础内径(β=-0.35,P0.001)呈负相关。FMD随年龄增长而下降,女性的FMD值大于男性,但在40岁左右迅速下降,在55岁后与男性无差异。结论:在中国人群中,心血管危险因素如年龄、性别、体质指数、腰围、收缩压、空腹血糖、总胆固醇、吸烟和肱动脉基础内径与血管内皮功能损害的发生有关。心血管危险因素对女性内皮功能的影响大于男性。     

福辛普利对老年高血压患者内皮依赖性血管舒张功能的影响

目的探讨福辛普利对老年高血压患者内皮依赖性血管舒张功能(FMD)的影响及机制。方法应用高频彩色多普勒超声检测仪对68例老年高血压患者进行FMD的无创检查,并观察福辛普利治疗前后患者FMD的变化。结果福辛普利治疗后老年高血压患者血管内径和硝酸甘油诱发的肱动脉内径变化率与治疗前无明显差异(P>0.05),但反应性充血诱发的肱动脉内径变化率较治疗前明显增加(P<0.05)。结论老年高血压患者出现明显FMD障碍,福辛普利治疗可改善老年高血压患者血管内皮功能。     

Is the Association Between Flow-Mediated Dilation and Cardiovascular Risk Limited to Low-Risk Populations?

OBJECTIVES: The aim of this research was to study whether the relation between endothelial function measured by flow-mediated dilation (FMD) of the brachial artery and cardiovascular risk factors is affected by the baseline cardiovascular risk. BACKGROUND: Flow-mediated dilation of the brachial artery is widely used as a measure of endothelial function. Relations between FMD and most cardiovascular risk factors have been described. METHODS: We performed a meta-regression analysis of 211 selected articles (399 populations) reporting on FMD and cardiovascular risk factors. Mean values of FMD; age; proportion of men; proportion of smokers; blood pressure; lipids; glucose; and the presence of diabetes mellitus, of hyperlipidemia, and of hypertension were retrieved from the articles. The 10-year risk of coronary heart disease (CHD) for each population was estimated based on the Framingham risk score. The relation between FMD and cardiovascular risk factors was assessed within each risk category by linear regression analysis, adjusting for age and gender, and weighted for the study size. RESULTS: A relation between FMD and cardiovascular risk factors was most clear in the category with lowest baseline risk (below 2.8% per decade). In populations with low baseline risk, for each % increase in Framingham risk, FMD decreased by 1.42% (95% confidence interval: 0.65 to 2.19). In medium- and high-risk populations, FMD was not related to risk (-0.02% [-0.27 to 0.22] and 0.06% [-0.02 to 0.13], respectively). These findings were independent of differences in brachial lumen diameter and technical aspects of the FMD measurement. CONCLUSIONS: Only in populations at low risk, endothelial function measured by FMD is related to the principal cardiovascular risk factors, and to the estimated 10-year risk of CHD.     

Vascular Endothelial Function and Self-reported Sleep

BackgroundThe authors investigated the relationship between self-reported sleep characteristics and brachial artery flow-mediated dilation (FMD) in a community-based population. Previous studies document that sleep apnea may be related to endothelial dysfunction but disagree whether subjective reports of sleep may also reflect such associations.MethodsIn 684 subjects (32% male) aged between 37 and 60 years enrolled in the Emory-Georgia Tech Predictive Health Institute study, the authors measured reported sleep characteristics using the Epworth Sleepiness Scale and the Pittsburgh Sleep Quality Index (PSQI) along with cardiovascular risk factors. Endothelial function was assessed using brachial artery FMD. Multivariate analysis of covariance was used to adjust for various cardiovascular risk factors including age, race, gender, smoking, hypertension, diabetes and body mass index.ResultsLower brachial artery FMD values were correlated with higher Epworth Sleepiness Scale scores (P = 0.0275), even after adjustment for risk factors (P = 0.03). Total PSQI score was unrelated to brachial artery FMD. However, lower sleep quality (PSQI component 1) was associated with lower brachial artery FMD (multivariate P = 0.038), and participants who coughed or snored during sleep also had lower brachial artery FMD (6.24% ± 3.42%) compared with those who did not (6.92% ± 4.30%) (P = 0.056). This difference remained significant after adjustment for risk factors (P = 0.03).ConclusionsIn a community-based population, our analysis indicates a significant association between sleepiness and snoring assessed by questionnaires and endothelial function. Simple subjective reports about individuals’ sleep may be highly revealing indicators of endothelial function impairment and thus important indicators of cardiovascular disease risk.     

Arterial elasticity identified by pulse wave analysis and its relation to endothelial function in patients with coronary artery disease

Patients with coronary artery disease (CAD) have impaired endothelial function. Arterial elasticity is modulated by endothelial function. The association between arterial elasticity and endothelial function has not been reported in patients with CAD. The present study was designed to investigate whether endothelial dysfunction contributes to impaired arterial elasticity. Thirty patients with CAD and 30 control subjects were recruited. Large and small artery elasticity indices were non-invasively assessed using pulse wave analysis. Brachial artery endothelium-dependent and -independent function were assessed by vascular response to flow-mediated vasodilation (FMD) and sublingual nitroglyceride (NTG), respectively. C1 large artery elasticity index was not different in the CAD group compared with the control group. However, C2 small artery elasticity index was significantly reduced in the CAD group compared with the control group. Flow-mediated vasodilation (FMD) was also impaired in the CAD group compared with the control group. Flow-mediated vasodilation (FMD) in the brachial artery correlated with C2 small arterial elasticity index. But NTG-mediated brachial artery vasodilation was similar between the two groups. The present findings suggest that the patients with CAD have reduced C2 small arterial elasticity index and impaired FMD. Endothelial dysfunction is involved in diminished arterial elasticity, suggesting that C2 small arterial elasticity index is a novel surrogate measure for the clinical evaluation of endothelial function.     

世居高原地区藏族、汉族冠状动脉慢血流现象患者凝血功能指标、红细胞相关指标及胆红素差异的病例对照研究

背景分析世居高原地区藏族、汉族冠状动脉慢血流现象(CSFP)患者凝血功能指标、红细胞相关指标及胆红素有助于了解世居高原人群CSFP特点及发病机制。目的比较世居高原地区藏族、汉族CSFP患者凝血功能指标、红细胞相关指标及胆红素的差异。方法选取2014-2016年在青海省心脑血管病专科医院干部保健科行冠状动脉造影并确诊为CSFP的患者222例,其中藏族患者93例(藏族组),汉族患者129例(汉族组)。比较两组患者及不同海拔高度藏族、汉族CSFP患者凝血功能指标[包括凝血酶原时间(PT)和D-二聚体(D-Dimer)]、红细胞相关指标[包括红细胞计数(RBC)、血红蛋白(Hb)、红细胞比容(HCT)、平均红细胞体积(MCV)及红细胞分布宽度(RDW)]、胆红素[包括总胆红素(TBiL)、直接胆红素(DBiL)及间接胆红素(IBiL)]。结果 (1)两组患者RBC、Hb、HCT、DBiL LC较,差异无统计学意义(P>0.05);汉族组患者PT短于藏族组,D-Dimer低于藏族组,MCV、TBiL、IBiL高于藏族组,RDW小于藏族组(P<0.05)。(2)不同海拔高度藏族CSFP患者D-Dimer、MCV、TBiL、DBiL、IBiL比较,差异无统计学意义(P>0.05)。海拔高度较高的藏族CSFP患者PT长于海拔高度较低者,RDW高于海拔高度较低者,RBC、Hb、HCT高于海拔高度较低和中等者(P<0.05)。(3)不同海拔高度汉族CSFP患者PT、D-dimer、MCV、RDW、TBiL、DBiL比较,差异无统计学意义(P>0.05)。海拔高度中等和较高的汉族CSFP患者RBC、Hb、HCT高于海拔高度较低者,海拔高度较高的汉族CSFP患者RBC、Hb、HCT及IBiL高于海拔高度中等者(P<0.05)。结论世居高原地区藏族、汉族CSFP患者PT、D-Dimer、MCV、RDW、TBiL、IBiL存在差异。     

Peripheral vascular endothelial function correlates with exercise capacity in women

BACKGROUND: Vascular endothelial function has been observed to correlate with exercise capacity in predominantly male populations. Gender-based differences exist in the clinical course of coronary artery disease, and previous studies indicate that estrogen may influence endothelial function. These observations raise the possibility that the relationship between endothelial function and exercise capacity in women may differ from that in men. HYPOTHESIS: This study aimed to determine whether peripheral vascular endothelial function correlates with exercise capacity in women. METHODS: Women who were referred for clinically indicated exercise testing with technetium-99 myocardial perfusion imaging were consecutively recruited. To ensure a population free of exercise limitation due to ischemic heart disease, women without myocardial perfusion defects were included for analysis in this study (n = 105). Endothelial function was assessed by brachial artery ultrasound flow-mediated vasodilation (FMD). Exercise capacity was defined as the duration of exercise on a symptom-limited Bruce protocol. RESULTS: Mean FMD was 11.8 +/- 0.6%, and median FMD was 12%. Subjects with an FMD less than the median of 12% had a significantly shorter exercise time than those with FMD > or = 12% (411 +/- 17 vs. 482 +/- 24 s, p = 0.014). There was a significant correlation between FMD and exercise time (r = 0.34, p < 0.001). Age and body mass index were additional predictors of exercise time; however, the relationship between FMD and exercise time was independent of these variables. CONCLUSION: Brachial artery FMD correlates with exercise capacity in women, even in the absence of ischemic heart disease.     

Measurement of flow-mediated dilatation of the brachial artery is affected by local elastic vessel wall properties in high-risk patients

OBJECTIVES: To assess whether the validity of endothelial function measurement by flow-mediated dilatation (FMD) is affected by local brachial artery stiffness (distensibility coefficient; DC) and arterial wall thickness (intima-media thickness, IMT). BACKGROUND: FMD measurement relies on assessment of arterial diameter change. Increased IMT and decreased DC might physically limit dilatation of the brachial artery in spite of healthy endothelium. METHODS: DC, IMT and FMD of the brachial artery were simultaneously measured in 349 patients with advanced atherosclerosis or cardiovascular risk factors. The relations between FMD and age, and FMD and current smoking were regarded as a proxy for the relation between FMD and true endothelial function. RESULTS: The relations between FMD and age, and FMD and smoking, were significantly modified by brachial artery DC. No modification was found for IMT. The interaction terms were statistically significant (p=0.03 and 0.04, respectively). The relation between FMD and age, and FMD and smoking was progressively more pronounced in patients with more elastic arteries. CONCLUSION: The results of our study indicate that increased arterial stiffness may interfere with valid measurement of FMD and that patients with stiff arteries may be considered for exclusion from analyses involving FMD to ensure its validity.     

Correlation of endothelial function in large and small arteries in human essential hypertension

OBJECTIVES: The structure and function of blood vessels varies along the vascular tree, and alterations found in hypertension are also different. The aim of this study was to determine whether non-invasive measurement of endothelial function in conduit arteries reflects that of subcutaneous resistance arteries measured in vitro. METHODS AND RESULTS: Sixteen essential hypertensive patients (aged 50 +/- 2 years) were studied. Flow-mediated dilation (FMD) during reactive hyperemia (endothelium-dependent) and sublingual nitroglycerin (NTG)-induced dilatation (endothelium-independent) were assessed in brachial arteries by ultrasound. Structure, and acetylcholine (10(-9) to 10(-4) mol/l) and sodium nitroprusside (SNP, 10(-8) to 10(-3) mol/l)-induced vasorelaxation of resistance arteries dissected from gluteal subcutaneous biopsies were measured in vitro using a pressurized myograph. Brachial artery FMD and NTG-induced dilatation were 8.4 +/- 1.0 and 18.1 +/- 1.4%, respectively. Resistance arteries of hypertensive patients showed greater media:lumen ratio (8.6 +/- 0.4 versus 5.9 +/- 0.3% in normotensive subjects, P< 0.01), and maximal acetylcholine responses was diminished to 75 +/- 6% compared to normotensive subjects (97 +/- 2%, P< 0.01). FMD correlated with maximal acetylcholine responses (r2 = 0.57, P< 0.001). FMD did not correlate significantly with the media: lumen ratio of resistance arteries (r2 = -0.22, P= 0.07). By multivariate analysis, FMD predicted resistance artery endothelial function independently of age, sex, body mass index, blood lipid status and lumen diameter of brachial artery (beta = 0.81, P< 0.001). CONCLUSIONS: Endothelial dilatory responses are similar in large and small arteries in hypertensive patients. Abnormal FMD in the brachial artery predicts the presence of endothelial dysfunction in human resistance arteries, suggesting that impairment of endothelial function is a generalized alteration in hypertension. Ultrasound measurement of endothelial dysfunction in the brachial artery appears to be less sensitive than in-vitro measurement in resistance arteries.     

Arterial structure and function in young adults with the metabolic syndrome: the Cardiovascular Risk in Young Finns Study.

AIMS: To study the relations between the metabolic syndrome (MS) and subclinical atherosclerosis in young adults. METHODS AND RESULTS: International Diabetes Federation (msIDF), National Institute of Health Adult Treatment Panel III (msNCEP), and European Group for the Study of Insulin Resistance (msEGIR) definitions of MS were related to carotid artery intima-media thickness (cIMT), brachial flow-mediated dilatation (FMD), and carotid artery compliance (CAC) in 2163 Finnish adults (aged 32 +/- 5years). All definitions associated with increased cIMT and decreased CAC in both sexes. The cIMT values (mean+/-SD) were 0.576 +/- 0.088 mm in subjects without the syndrome, 0.615 +/- 0.102 mm in msIDF, 0.617 +/- 0.104 mm in msNCEP, and 0.607 +/- 0.097 mm in msEGIR (P < 0.0001). Corresponding CAC values were 2.26 +/- 0.72, 1.76 +/- 0.66, 1.73 +/- 0.66, 1.72 +/- 0.66%/10 mmHg (P < 0.001). Impaired brachial FMD was not related to MS but it modified the relations between MS and cIMT: MS correlated with increased cIMT in subjects with an impaired FMD response (P = 0.003) but not in subjects with an enhanced FMD response (P = 0.75). CONCLUSION: All current definitions of MS identify a population of young adults with evidence of increased subclinical atherosclerosis. Impaired brachial endothelial response is not a hallmark of MS in young adults, but the status of endothelial function modifies the association between metabolic risk factors and atherosclerosis.     

Close association of endothelial dysfunction with insulin resistance and carotid wall thickening in hypertension

BACKGROUND: Endothelial dysfunction has been regarded as an early stage in the atherosclerotic process. Endothelial dysfunction and insulin resistance were observed in hypertensive subjects and were associated with carotid wall thickening. METHODS: We examined the determinants of endothelial dysfunction including insulin sensitivity and carotid wall thickening. A total of 41 subjects with nondiabetic essential hypertension were studied. Endothelial function of brachial artery and carotid wall thickening were assessed noninvasively using ultrasound technique. In brachial artery, we measured flow-mediated endothelium-dependent vasodilation (FMD) and glyceryl trinitrate-induced endothelium-independent vasodilation (GTN). We estimated intima-media thickness of the common carotid artery (IMT). Insulin sensitivity was measured according to the steady-state plasma glucose (SSPG) method. High SSPG levels indicated insulin resistance. RESULTS: On univariate analysis, there were significant negative correlations between FMD and SSPG (r = -0.695, P <.0001) or IMT (r = -0.449, P <.004). The FMD was negatively correlated significantly with age and with systolic and diastolic blood pressures (BP). A significant negative correlation was observed between GTN and SSPG. There was a significant positive relation between SSPG and IMT. On multiple regression analysis including systolic BP, SSPG, and age as independent variables and FMD as a dependent variable, FMD was independently related to SSPG (P <.03) and systolic BP (P <.02). If the presence of SSPG, diastolic BP, and age were entered as independent variables against FMD, FMD was independently related to SSPG (P <.002). CONCLUSIONS: One of the major determinants of endothelial function was insulin resistance. Our findings suggest that endothelial dysfunction and early structural vascular changes were related to insulin resistance.     

Endothelial function in patients with obstructive sleep apnea syndrome but without hypertension

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) influences endothelial function and causes hypertension. OBJECTIVES: Our aim was to evaluate the role of endothelial dysfunction in the pathogenesis of hypertension in OSAS. METHODS: Twenty-three patients with OSAS but without hypertension and 15 healthy normotensive subjects were investigated. The presence or absence of OSAS was evaluated with a sleep study. Endothelial function was investigated with brachial artery ultrasound examination. RESULTS: Baseline characteristics were equivalent between the two groups. Minimal oxygen saturation and apnea-hypopnea indexes in the OSAS and control groups were 62.9 +/- 16.5 versus 94.9 +/- 1.1% (p < 0.0001) and 53.1 +/- 20.3 versus 3.8 +/- 0.9 (p < 0.0001), respectively. There was not statistically significant difference between basal brachial artery diameters measured in the morning and in the evening in all groups. Flow-mediated dilation (FMD) values measured in the morning were lower than those measured in the evening in both OSAS patients and the control group: FMD of OSAS patients was 6.04 +/- 3.18% in the morning and 10.38 +/- 4.23% in the evening hours (p = 0.001), and FMD of control subjects was 10.9 +/- 2.6% in the morning and 13.9 +/- 2.32 in the evening hours (p = 0.002). Differences in FMD values measured both in the morning and evening hours in OSAS patients were lower compared with those in control subjects (p < 0.0001 in the morning hours and p = 0.003 in the evening hours). CONCLUSIONS: We detected a prominent diurnal deterioration in endothelial function in normotensive OSAS patients compared with healthy subjects. This deterioration may occur due to ongoing hypoxemia during the night and it may be a possible cause of hypertension and atherosclerotic cardiovascular diseases in patients with OSAS.