Effect of smoking on endothelial function and wall thickness of brachial artery.

BACKGROUND: Impaired flow mediated dilatation (FMD) and increased wall thickness (WT) of the brachial artery have been associated with atherosclerosis and its risk factors. In this study we sought to determine brachial artery wall thickness in chronic smokers and the instantaneous effect of smoking on brachial artery endothelium dependent vasodilator function in smokers and non-smokers. METHOD AND RESULTS: Using a high-resolution ultrasound, WT of posterior brachial artery wall, the diameter of brachial artery at rest and during reactive hyperemia (FMD %), as well as after sublingual administration of nitroglycerine (nitroglycerine mediated dilatation (NMD) %) was measured in 20 smokers and 20 non-smokers. Wall thickness (WT) of the posterior brachial artery wall and the wall index (WI) were greater in smokers than non-smokers. The baseline brachial artery diameter was comparable in smokers and non-smokers. Flow mediated dilation (FMD) was found to be less in smokers than non-smokers. The NMD in smokers also did not differ significantly from that in non-smokers. Flow mediated dilation significantly reduced after smoking compared to baseline in both groups. However, NMD remained unchanged after smoking in both groups. CONCLUSIONS: Increased WT and impaired endothelium-dependent dilatation of brachial artery suggests that cigarette smoking disrupts vessel wall morphology long before atherosclerosis is manifest.     

厄贝沙坦氢氯噻嗪对肱动脉内皮功能及颈动脉内膜中层厚度的影响

目的观察厄贝沙坦氢氯噻嗪对高血压患者肱动脉内皮功能及颈动脉内膜中层厚度的影响。方法选择2010年6月~2013年2月在徐州医学院附属医院老年科就诊的1级、2级原发性高血压患者137例,完成本研究127例,随机分为氢氯噻嗪组60例及厄贝沙坦氢氯噻嗪67例。2组患者每日晨起分别口服氢氯噻嗪25 mg及厄贝沙坦氢氯噻嗪1片,连续12个月。检测2组患者治疗前后血压、血脂、高敏C反应蛋白(hs-CRP)等指标,以及肱动脉内皮依赖性舒张功能(EDD)和颈动脉内膜中层厚度(IMT)的变化。结果与治疗前比较,氢氯噻嗪组和厄贝沙坦氢氯噻嗪组治疗后收缩压[(156.49±9.10)mm Hg vs.(126.37±8.12)mm Hg,(157.26±8.91)mm Hg vs.(124.46±8.07)mm Hg]、舒张压[(98.73±5.54)mm Hg vs.(77.65±5.42)mm Hg,(99.54±5.38)mm Hg vs.(76.36±5.71)mm Hg]均降低,差异具有显著统计学意义(P均0.01)。与治疗前比较,厄贝沙坦氢氯噻嗪组患者治疗后内皮依赖性舒张功能[(5.37±0.91)%vs.(6.79±1.08)%,P0.01]提高,颈动脉内膜中层厚度[(1.16±0.25)mm vs.(1.03±0.20)mm,P0.05]降低。与氢氯噻嗪组患者治疗后比较,厄贝沙坦氢氯噻嗪组患者治疗后内皮依赖性舒张功能[(5.56±0.99)%vs.(6.79±1.08)%,P0.01]提高,颈动脉内膜中层厚度[(1.15±0.19)mm vs.(1.03±0.20)mm,P0.05]下降。结论厄贝沙坦氢氯噻嗪降压的同时可以改善肱动脉内皮功能、减少颈动脉内膜中层厚度。     

L-精氨酸对肱动脉内皮功能的改善作用

目的:探讨L-精氨酸(L-Arg)对人血管内皮功能的影响。方法:以高分辨率超声对住院患者行肱动脉内皮功能测定,血流介导的肱动脉内径变化率(FMD%)被用来评估血管内皮功能,硝酸甘油诱发的血管扩张(NMD%)被用来反映血管平滑肌功能。以38例存在肱动脉内皮功能不全的住院患者为研究对象,分为2组,静脉滴注L-Arg(A组)及口服L-Arg(B组)。2组治疗2周后复查FMD%及NMD%。比较治疗前后FMD%及NMD%的变化,同时比较2组肱动脉内皮功能有无差异。结果:2组治疗后FMD%高于治疗前,治疗前后比较FMD%差异有统计学意义(P<0.01);而2组治疗前后NMD%差异无统计学意义(P>0.05)。结论:静脉滴注和口服L-Arg均具有改善肱动脉内皮功能的作用,疗效无明显不同。     

肱动脉内皮功能对老年冠心病患者的预测价值

目的 探讨肱动脉内皮功能对老年冠心病患者的预测价值.方法 测定98例冠心病患者及37例对照者肱动脉内皮依赖血管舒张功能(FMD)及非内皮依赖血管舒张功能(NMD),根据冠脉造影结果将患者分为冠脉病变＜50%,50%～75%,＞75%病变组和冠脉病变0、1、2、3支病变组,以比较老年冠心病患者冠脉病变程度、范围与肱动脉F...     

超声检查评价老年糖尿病患者肱动脉内皮功能的价值与局限性

目的探讨超声测定肱动脉舒张功能评价老年糖尿病患者血管内皮功能的价值与局限性。方法用高分辨率二维超声测定反应性充血时血流介导肱动脉舒张功能（FMD）技术对67例老年T2DM患者（DM组）血管内皮功能进行评价。结果DM组肱动脉基础内径及基础流速与正常对照（NC）组无统计学差异,加压反应性充血后均可见血管扩张,血液流速增加,DM组加压后肱动脉内径增加及流速增加显著低于NC组;单因素线性相关性分析FMD与病程、TG、ISI和年龄呈负相关（P〈0．05或P〈0．01）,而与BMI、TC、FPG、HbA1c、Fins不相关。结论FMD对评价老年T2DM患者血流介导的血管内皮舒张功能障碍有一定的价值,但要综合考虑病人的年龄、性别、种族、病程、血脂等因素。     

Prognostic value of posterior wall thickness in childhood dilated cardiomyopathy and myocarditis

M-mode indices of left ventricular dimension and posterior wallthickness were derived from echocardiograms of children presentingwith dilated cardiomyopathy/myocarditis and were related tooutcome. Echocardiograms from 16 of 18 children were manuallydigitized to obtain changes of left ventricular dimension andposterior wall thickness throughout the cardiac cycle. Indicesof ventricular function and the ratio of end-diastolic posteriorwall thickness to cavity dimensions were obtained. Patients were divided into group I (alive, n=7), and group II(died, n=6 or heart transplantation, n=3) at median follow-upof 25 months. No significant difference was seen for the shorteningfraction, the percentage of posterior wall thickening or thenormalized peak rate of left ventricular filling. The normalizedpeak rate of posterior wall thinning was greater in group II.The posterior wall thickness to cavity dimension ratio was higherin group I (median=0·19) than group II (median=0·13)(P<0·005). Five of six survivors, whose ventricularfunction improved, had ratios >0·17. All but one witha ratio 0·16 remained with a dilated heart, died or requiredtransplantation (P=<0·01). A relatively thicker posterior wall (ratio >0·17)was associated with better prognosis and recovery. This indexshould be taken into account in decision-making regarding timingfor cardiac transplantation.     

高血压合并冠状动脉狭窄患者肱动脉内皮功能研究

目的:观察高血压合并冠心病患者血流介导的肱动脉扩张(FMD)的程度,探讨冠心病患者冠脉病变支数与FMD的关系。方法:选取在我科行冠脉造影检查的高血压患者160例。依据冠脉造影结果分为1、高血压合并冠心病组(冠心病组,98例),并依据冠脉造影(冠脉狭窄≥50%)再分为:①单支病变组(35例);②双支病变组(47例);③多支病变组(16例);2、高血压组(对照组,62例)。通过超声检测肱动脉基础状态,去压30秒、60秒的内径变化(FMD)。以Logistic回归分析:冠脉病变支数与FMD的关系。结果:冠心病组的FMD(7.41±0.73)显著小于高血压组的(10.51±0.68,P0.05)。冠心病单支、双支、多支病变组的FMD组间比较均有显著差异(P均0.05)病变支数越多,FMD越小,去压60秒的FMD为[单支病变组(7.01±0.29)、双支病变组(6.82±0.35)、多支病变组(6.09±0.29)。多元Logistic回归分析显示,与FMD关系密切的依次为冠状动脉多支病变去压后60秒(OR=3.158,P=0.000)、双支病变去压后30秒(OR=1.163,P=0.003)、单支病变去压后30秒(OR=1.076,P=0.004)。结论:高血压合并冠心病患者随着冠脉病变程度增加,动脉内皮功能损害就越重,呈负相关。检测血流介导的肱动脉扩张有助判断冠脉病变程度。     

Non-invasive measurement of endothelial function: effect on brachial artery dilatation of graded endothelial dependent and independent stimuli.

OBJECTIVE: To examine the relation between endothelial dependent and endothelial independent stimuli of varying intensity and measures of vascular function in the brachial artery of young healthy adults, to determine whether these responses are consistent and can be used to assess endothelial function. DESIGN AND SETTING: High resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperaemia induced by forearm cuff occlusion, and after sublingual isosorbide dinitrate (ISDN). Each subject was assigned to a random order of six cuff occlusion times (30 seconds, 1.5, 2.5, 3.5, 4.5, and 8 minutes) and six doses of ISDN (10, 20, 50, 100, 200, and 400 micrograms). SUBJECTS: Three males and three females mean age 31 years (range 25 to 43) with no known risk factors for cardiovascular disease. MAIN OUTCOME MEASURES: Flow mediated, endothelial dependent dilatation was compared to duration of cuff occlusion, peak reactive hyperaemia, and duration of increased flow. Nitrate induced, endothelial independent dilatation was compared to dose of ISDN and change in flow. RESULTS: Vessel dilatation and duration of peak flow change increased with longer duration of cuff occlusion. After 4.5 minutes of occlusion, flow mediated dilatation was mean (SD) 96 (6)% of maximal response and did not increase significantly with longer occlusion times. No significant dilatation occurred after 10 or 20 micrograms of ISDN in any subject. With increasing doses up to 200 micrograms there was an increase in dilatation. Endothelial independent dilatation did not increase significantly with doses of ISDN above 200 micrograms. CONCLUSIONS: Measures of arterial function vary with duration of blood flow occlusion and ISDN dose. Maximum arterial response was reached in all subjects after 4.5 minutes of blood flow occlusion or 200 micrograms of ISDN. Therefore, these variables produce consistent reproducible measures of endothelial function.     

Impaired brachial artery endothelial function is not predicted by elevated triglycerides

OBJECTIVES

The purpose of this study was to determine if patients with modest hyperlipidemia, and no other risk factors for coronary artery disease (CAD), have impaired endothelium-dependent (ED) vasoactivity.

BACKGROUND

Hypercholesterolemia impairs ED vasodilation, but the impact of elevated triglycerides on endothelial function is not as well established.

METHODS

High-resolution ultrasound was used to determine flow-mediated dilation (FMD) in the brachial artery (BA) after a 5-min arterial occlusion (endothelium-dependent stimulus) and nitroglycerin-induced dilation (endothelium-independent stimulus). We studied 40 healthy controls (Group 1), 38 patients with elevated low-density lipoprotein (LDL) cholesterol (Group 2) and 35 patients with elevated triglycerides (Group 3). Patients were excluded if they had known CAD or other risk factors for CAD, or if they were receiving lipid-lowering or vasoactive medications.

RESULTS

Control patients (Group 1) had normal LDL cholesterol (2.6 ± 0.8 mmol/liter) and triglyceride levels (1.0 ± 0.5 mmol/liter) compared with Group 2 (5.2 ± 1.2 mmol/liter, 1.8 ± 0.6 mmol/liter) and Group 3 (3.5 ± 0.9 mmol/liter, 4.2 ± 2.5 mmol/liter) subjects (p < 0.001). Baseline BA diameters were the same across the three groups. There was no significant attenuation of flow-mediated vasodilation (FMD) in either of the hyperlipidemic groups (Group 1: 10.9 ± 5.0% vs. Group 2: 8.6 ± 6.1% vs. Group 3: 9.4 ± 3.9%; p = 0.14). However, nitroglycerin-induced vasodilation was mildly reduced (Group 1: 21.0 ± 5.0% vs. 16.9 ± 7.6% vs. 17.3 ± 7.7%; p = 0.01). By multivariate analysis, after controlling for baseline diameters, only the ratio of LDL/high-density lipoprotein predicted a minor impairment in FMD.

CONCLUSIONS

In patients free from other cardiac risk factors, modest elevations of triglycerides or LDL cholesterol do not significantly attenuate BA endothelial-dependent vasodilation. Synergism with other cardiac risk factors may be required to significantly impair endothelial function in these patients.     

Short- and long-term influence of diet and simvastatin on brachial artery endothelial function

BACKGROUND: Endothelium-dependent dilation (EDD) has often been studied in patients with hypercholesterolemia without overt coronary atherosclerosis where an improvement after statin treatment has been documented within few weeks. The aim of the study was to assess the short-term effect of diet as well as short- and long-term effect of simvastatin on EDD in patients with hypercholesterolemia and ischemic heart disease. METHODS: In 43 male patients with hypercholesterolemia and ischemic heart disease, EDD of the brachial artery was measured at baseline, after 3 months on a lipid-lowering diet, and after another 1, 3 and 12 months on simvastatin at 40 mg/day. RESULTS: Three months changes in EDD were neither influenced by diet nor short-term simvastatin therapy (4.9% vs. 4.9% vs. 4.8%, p=ns). Twelve months simvastatin treatment, however, significantly improved EDD by 32.7% (4.9% vs. 6.5%, p=0.007). By regression analysis an individual adjusted increase in EDD during the simvastatin treatment period was seen (coefficient 0.132 a month, p=0.002). A significant reduction in total cholesterol of 31.0% (6.1+/-0.8 vs. 4.2+/-0.7, p<0.001) and LDL cholesterol of 42.6% (4.0+/-0.8 vs. 2.2+/-0.6, p<0.001) was observed. CONCLUSION: EDD is improved after long-term simvastatin therapy; however, neither did 3 months diet or 3 months simvastatin therapy has influence on the EDD.     

Association of wall thickness of the brachial artery measured with high-resolution ultrasound with risk factors and coronary artery disease

Intima-media thickness of the carotid and femoral arteries has been associated with coronary atherosclerosis and its clinical sequelae. The brachial artery (BA) is widely used for the assessment of flow-mediated vasodilation. The aim of this study was to examine whether BA wall thickness (WT) is associated with coronary artery disease (CAD) and risk factors. High-resolution ultrasound (13 MHz) examination of the BA was performed in 179 patients undergoing coronary angiography for the evaluation of chest pain. CAD (> or =30% diameter stenosis in > or =1 major branch) was found in 132 patients, whereas 47 patients had smooth coronary arteries. WT of the posterior BA wall (0.4 +/- 0.05 vs 0.35 +/- 0.06 mm, p <0.001) and wall index (WI) (WT/vessel diameter x 100; 16.1 +/- 0.0 vs 13.8 +/- 0.8, p <0.001) were greater in patients with than without CAD. On univariate analysis, WT and WI correlated with age, presence of CAD, systemic hypertension, maximum coronary diameter stenosis, and baseline diameter. On logistic regression analyses adjusting for age, cholesterol levels, systemic hypertension, smoking, and positive family history, WT (p <0.01) and WI (p = 0.02) remained significantly correlated with the presence of CAD. Thus, BA-WT is independently correlated with the presence of CAD. WT may provide a novel noninvasive marker of atherosclerosis that can be assessed together with flow-mediated vasodilation to yield functional and morphologic information in the same vessel.     

Comparison of endothelial function evaluated by strain gauge plethysmography and brachial artery ultrasound

BACKGROUND: the cardiac Renin-Angiotensin system (RAS) plays an important role in the regulation of coronary flow and cardiac function and structure in normal and pathological conditions such as ischemia-reperfusion (I/R) injury. The aim of this study was to investigate the effects of the Angiotensin II type 1 (AT-1) receptor antagonist MK-954 (losartan potassium) on postischemic endothelial dysfunction and NOS mRNA expression (inducible nitric oxide synthase, iNOS; endothelial nitric oxide synthase, eNOS) in isolated working rat hearts. METHODS: isolated working rat hearts were subjected to 15 min global ischemia and 180 min reperfusion. MK-954 was added to perfusion buffer (a modified Krebs-Henseleit solution) at 1 microM concentration. We assessed functional parameters, creatin kinase (CK) release, heart weight changes, microvascular postischemic hyperpermeability (FITC-albumin extravasation) and morphological ultrastructural alterations. eNOS and iNOS mRNA levels were also detected by the means of multiplex RT-PCR technique using glyceraldehyde-3-phosphate dehydrogenase (G3PDH) gene as internal control; results were expressed as densitometric ratio. RESULTS: in Losartan-treated hearts we observed a significant reduction of postischemic contractile dysfunction, CK release and myocardial ultrastructural damage; postischemic FITC-albumin extravasation was significantly reduced respect to controls. Moreover, 1 microM Losartan produced a significant reduction of eNOS/G3PDH respect to untreated hearts submitted to I/R. Regarding iNOS/G3PDH ratio, no significant changes were detected in Losartan-treated hearts compared with controls. CONCLUSIONS: our study revealed that Losartan treatment before ischemia, and during reperfusion, is able to reduce the reperfusion injury of the rat heart by reducing mechanical and microcirculatory dysfunction and necrotic cell death, ameliorating cardiac ultrastructure and endothelial protection, probably inducing eNOS over-expression and reducing post-ischemic hyperpermeability of coronary microcirculation.     

高血压前期颈动脉内-中膜厚度及血管内皮舒张功能的变化

目的探索高血压前期外周动脉血管粥样硬化和血管内皮功能的改变。方法检测颈动脉内-中膜厚度（IMT）和肱动脉内皮舒张功能。结果高血压前期组颈动脉分叉、颈总动脉处内-中膜厚度均较正常血压组增厚（P〈0．05）;高血压前期组反应性充血后肱动脉内径变化率（FMD）显著低于正常血压组（P〈0．05）;含服硝酸甘油后肱动脉内径FMD高血压前期组与正常血压组无明显差异（P〉0．05）。结论高血压前期已存在颈动脉内-中膜增厚,血管内皮功能已经受损。     

Whole-body periodic acceleration enhances brachial endothelial function.

BACKGROUND: Periodic acceleration in the direction of the spinal axis through repetitive movement increases the shear stress on the vascular endothelium. In the present study it was assessed whether whole-body periodic acceleration with a new device would enhance endothelial function in sedentary adult volunteers. METHODS AND RESULTS: Twenty-six sedentary subjects (44+/-3 years) were randomly assigned to remain sedentary or perform exercise training for 4 weeks, followed by crossover. Periodic acceleration was applied with a horizontal motion platform at 2-3 Hz and approximately +/-2.2 m/s2 for 45 min. Increases in the brachial artery diameter were examined at rest, during reactive hyperemia (flow-mediated dilatation: %FMD) and after sublingual administration of 0.3 mg nitroglycerin (%NTG) using high-resolution ultrasound. All subjects completed the study with no adverse side-effects. There were no significant changes in the resting heart rate or arterial pressure, body weight, or lipid profiles during the study. Although %FMD did not change during the non-training period with periodic acceleration, it significantly increased from 7.3+/-0.4% at baseline to 8.4+/-0.4% after the training period (p<0.05), while %NTG remained unchanged. CONCLUSIONS: Whole-body periodic acceleration with a horizontal motion platform improved vascular endothelial function in sedentary adults. This device might offer an alternative to active exercise for patients whose medical condition limits physical activity.     

踝臂指数、颈动脉内中膜厚度对冠状动脉硬化早期预测价值

目的探讨踝臂指数（ABI）与颈动脉内中膜厚度（IMT）的相关性及其对冠心病的预测价值。方法随机选择150例行冠脉造影检查的患者行ABI、IMT测定,调查其年龄、性别、高血压史、糖尿病病史、吸烟史以及身高、体重,计算体重指数,并测量血压,化验血糖、甘油三酯（TG）、总胆固醇（TC）、低密度脂蛋白胆固醇（LDL—C）和高密度脂蛋白胆固醇（HDL—C）等指标。用SYNTAX积分评价冠状动脉的病变程度,分析在不同病变程度下ABI和IMT之间的相关性。分别用ABI和IMT预测冠心病,并比较两者诊断的可靠程度。结果①以SYNTAX评分判定,ABI除冠脉正常组和轻病变组间差异无统计学意义（p=O．126）外,其余各组间差异均有统计学意义（P〈0．01）,冠状动脉病变越严重,ABI越低。IMT除中、重病变组间差异无统计学意义（P=0．055）外,余各冠状动脉组问差异均有统计学意义（P〈0．05）,冠状动脉病变越严重,IMT值越大。②以SYNTAX积分为协变量,计算ABI与IMT的偏相关系数,两者为负相关（r=一0．499,P=0．000）。SYNTAX积分为分组变量情况下分析ABI和IMT的相关性,显示在冠脉有病变的情况下两者呈负相关。③分别作ABI、IMT预测冠心病的ROC曲线,ABI=0．95,预测冠心病的灵敏度为85．2％,特异度为75．3％;IMT=1．51mm,预测冠心病的灵敏度为77．4％,特异度为64．4％。结论ABI、IMT与冠状动脉硬化程度密切相关,冠脉病变患者ABI越低则IMT越厚。ABI和IMT两种检测方法均对冠状动脉病变程度的评估具有价值,且二者协同互补,可以改善无创检查的敏感性及特异性。ABI和IMT作为非侵入性检测,对筛查无症状冠心病患者及评估冠心病严重程度具有重要意义。     

Gender differences in wall shear-mediated brachial artery vasoconstriction and vasodilation.

OBJECTIVES: We sought to investigate wall shear rate (WSR) and brachial artery diameter (BAD) changes simultaneously and to determine whether any gender differences exist in arterial reactivity. BACKGROUND: Wall shear rate/stress and arterial reactivity are rarely assessed at the same time. Furthermore, flow-mediated vasoconstriction has received less attention than flow-mediated vasodilation in humans. METHODS: A new noninvasive evaluation of WSR in the brachial artery, using multigated, pulsed Doppler velocimeter and a double-transducer probe moved and fixed by a robotic system, was developed. RESULTS: The validity of the system was tested in vitro with calibrated tubes and showed a high correlation (r = 0.98, p < 0.001). In 10 men and 10 women of similar age, induction of low and high shear rates by forearm occlusion produced significant vasoconstriction and vasodilation, respectively. The time lag for maximal BAD changes was 3 min for vasoconstriction and 1 min for vasodilation. A greater half-time for vasodilation (96 +/- 6 for men and 86 +/- 12 s for women) than for shear rate (31 +/- 5 s for men and 34 +/- 4 s for women) was observed after discontinuation of occlusion. Relative BAD was correlated with WSR changes, showing a significantly higher slope in women than in men (p < 0.01). Moreover, a larger normalized arterial diameter per shear rate was observed for vasoconstriction (p < 0.01) and vasodilation (p < 0.01) in women than in men. CONCLUSIONS: Shear-mediated arterial vasodilation and vasoconstriction were more pronounced in women than in men, suggesting different gender-related sensitivity in the regulation of large-artery vascular tone.     

高血压患者颈动脉内膜中层厚度及血管内皮依赖性舒张功能的改变

目的：观察老年高血压对颈动脉内膜中层厚度（IMT）及血管内皮依赖性舒张功能（EDD）的影响及其临床意义。方法：分别选择对照组40例。高血压组60例。使用E1立EUB-6500彩色多普勒超声诊断仪，探头频率10MHz，测量颈动脉IMT，EDD。结果：高血压组动脉IMT明显增厚，平均（0.912±0．263）mm。血管内皮依赖性舒张功能EDD明显下降，与对照组间均有显著性差异（P〈0.01）。结论：颈动脉内膜中层厚度增厚及血管内皮依赖性舒张功能障碍是老年高血压患者动脉粥样硬化的早期表现。