肱动脉血流介导的舒张功能与冠状动脉病变的关系

目的:观察冠心病(CHS)患者肱动脉血流介导的舒张功能与冠状动脉(冠脉)病变之间的关系。方法:选择冠脉造影(CAG)患者107例,根据cAG结果分为冠脉正常组28例、冠脉早期病变组31例、CHD组48 例,CHD组采用Gensini评分进一步分为轻度病变(1-20分)26例,重度病变(≥20分)22例。在CAG前24 h 内应用高分辨率超声检测肱动脉血流介导的舒张功能,与CAG结果作对照分析。结果:CHD组中轻度病变与重度病变者较冠脉早期病变组及冠脉正常组的肱动脉内皮依赖的舒张功能(EDD)明显降低[(4．75±0．94)％、 (3．67±1．01)％:(5．98±0．89)％、(6．15±0．97)％,P<0．05或0．01];重度冠脉病变者EDD较轻度冠脉病变者明显下降[(3．67±1．01)％:(4．75±0．94)％,P<0．05]。而硝酸甘油介导的血管扩张功能(非EDD)在各组间差异无统计学意义(P>0．05)。肱动脉EDD与冠脉病变积分呈负相关(r=0．72,P<0．01)。结论: CHD患者常存在肱动脉EDD受损,肱动脉EDD可间接反映冠脉病变程度。     

Prognostic role of flow-mediated dilatation of the brachial artery in hypertensive patients

BACKGROUND: The prognostic role of endothelial dysfunction, as evaluated by flow-mediated vasodilatation of the brachial artery, has been demonstrated in patients at very high risk. We aimed to investigate whether flow-mediated vasodilatation predicts cardiovascular events in uncomplicated hypertensive patients. METHODS AND RESULTS: A total of 172 prospectively identified uncomplicated hypertensive patients (age 56 +/- 8 years, 41% women, 48 with diabetes mellitus type 2) were studied. At baseline all patients were untreated and underwent baseline standard laboratory examination. A standard echocardiogram was performed for the evaluation of left ventricular anatomy and function and patients with systolic dysfunction or left ventricular wall motion abnormalities were excluded. Endothelial function was measured as flow-mediated vasodilatation of the brachial artery using high-resolution ultrasound. Patients were followed for 95 +/- 37 months (range 2-136 months). A first nonfatal or fatal cardiovascular event occurred in 32 patients. The incidence of cardiovascular events was 1.4 and 3.1 per 100 patient-years in patients with a flow-mediated vasodilatation below and above the median value (4.7%), respectively (P < 0.005 by the log-rank test). In Cox analysis, controlling for age, sex, glycemia, cholesterol, smoking, BMI, systolic and diastolic blood pressure at baseline and left ventricular mass index, a low flow-mediated vasodilatation conferred an increased risk of cardiovascular events (odds ratio 2.67, 95% confidence interval 1.17 to 6.1, P = 0.02). CONCLUSION: The presence of endothelial dysfunction, as evaluated by flow-mediated vasodilatation of the brachial artery, identifies hypertensive patients at increased risk of nonfatal and fatal cardiovascular events.     

青年长期吸烟者血管内皮依赖性舒张功能的改变

目的:探讨青年长期吸烟血管内皮依赖性舒张功能的改变。方法:测定20例长期吸烟青年及15例正常对照者血流介导的和硝酸甘油介导的肱动脉内径改变。结果:两组肱动脉内径基础值(3.75±0 61mm:3.81±0.55mm)及硝酸甘油介导的肱动脉舒张[(22.13±7.65)％:(23.45±8.21)％]无显著差异(P>0.05),而血流介导的血管扩张存在显著差异.为[(3.61±2.90)％:(8.32±4.75)％]、P<0.01。单因素相关分析表明,肱动脉内皮依赖件舒张与吸烟量呈显著负相关(r=0.523.P<0.001).结论:青年长期吸烟者血管内皮依赖性舒张功能明显受损,受损程度与吸烟量有关。     

Decreased nitrate-mediated dilatation in patients with coronary artery ectasia: an ultrasonographic evaluation of brachial artery

BACKGROUND: Coronary artery ectasia has been defined as localized or diffuse nonobstructive lesions of the epicardial coronary arteries with a luminal dilation exceeding the 1.5-fold of normal adjacent segment or vessel diameter. Although coronary artery disease is supposed to be responsible for more than 50% of coronary ectasia, the precise pathology of coronary artery ectasia is not clearly understood. The brachial artery ultrasound test for flow-mediated endothelial-dependent vasodilatory function includes administration of sublingual nitrates to examine the vasodilating effect of an exogenous source of nitric oxide. In the present study, we aimed to compare flow-mediated and nitrate-mediated responses of brachial artery in patients with coronary artery ectasia and patients with coronary artery disease. MATERIALS AND METHODS: Thirty-six consecutive patients with coronary artery ectasia in combination with coronary artery disease and 42 age-matched and sex-matched patients with coronary artery disease alone were included in the study. Flow-mediated and nitrate-mediated dilatations were measured in all patients using a high-resolution B-mode ultrasonographic system. RESULTS: Baseline brachial artery diameters in patients with coronary artery ectasia were not statistically different from those in patients with coronary artery disease (4.2+/-0.6 vs. 4.0+/-0.6 mm, respectively, P=0.16). Although the forearm flow-mediated dilatation of the patients with coronary artery ectasia did not differ from that of patients with coronary artery disease alone (5.5+/-3.8 vs. 4.8+/-3.6%, respectively, P=0.41), nitrate-mediated dilatation was significantly lower than that of patients with coronary artery disease alone (7.9+/-5.2 vs. 10.9+/-5.4%, respectively, P=0.02). CONCLUSION: We have shown that patients with coronary artery ectasia have decreased nitrate-mediated response of brachial artery compared with patients with coronary artery disease alone, suggesting more severe dysfunction or, possibly, destruction of the media layer in coronary artery ectasia than in coronary artery disease.     

Characterization of the brachial artery shear stress following walking exercise

Habitual exercise provides repeated episodes of elevated vascular shear stress (SS), which may be a mechanism for repair of endothelial dysfunction in disease. Our aim was to determine the brachial artery SS during the 3-hour period following single bouts of low, moderate, and high-intensity walking exercise. In a randomized crossover design, 14 men walked for 45 minutes on a treadmill at 25%, 50% and 75% of VO2peak separated by 2-7 days. Using Doppler ultrasonography, brachial artery SS was assessed immediately after exercise and then hourly for 3 hours. High-intensity walking elicited greater (p<0.05) post-exercise SS compared with low and moderate intensity. In addition, a 3x4 (intensity x time) ANOVA indicated an absence of interaction (p=0.369) and a decline in post-exercise SS over time (p<0.0001) which was abolished after 2 hours. Thus, we found that brachial artery SS is greatest following high-intensity walking and that the rate of decline in SS is similar across all walking intensities.     

The effect of acute hyperglycaemia on brachial artery flow mediated dilatation in normal volunteers

Abstract Background : Endothelial function is known to be abnormal in patients with diabetes and acute hyperglycaemia may play an aetiological role.
Aims : The aim of this randomised controlled study was to determine if acute systemic hyperglycaemia impairs endothelial function in normal subjects.
Methods : Endothelial function was assessed by the change in brachial artery diameter in response to forearm ischaemia using B-mode ultrasound in ten healthy subjects (eight male) aged 19–35 years. Brachial artery blood flow velocity and diameter were measured before and after five minutes of forearm ischaemia. Measurements were performed in the supine position after an overnight fast, before and after 60 minute infusions of 0.9% saline or 10% dextrose. Measurements were made on two separate occasions at least 24 hours apart, and subjects were randomised to saline first or dextrose first. The largest diameter measured after ischaemia was divided by the resting arterial diameter to calculate percent dilatation of the artery from baseline, and is reported as flow-mediated dilatation (FMD).
Results : Dextrose infusion resulted in a significant rise in mean (SD) serum glucose 5.2 (0.1) to 9.2 (0.3) mmol/L and insulin concentration 6.3 (1.4) to 20.6 (3.7) mU/L p <0.002. Brachial artery blood flow velocity and diameter increased significantly from baseline after ischaemia ( p <0.002). Mean FMD (SEM) before and after infusion were not, however, significantly different ( p =0.4) (pre-saline 7.3 [1.0]%, post saline 5.2 [1.5]% and predextrose 8.1 [2.0]%, post dextrose 5.9 [1.7]%).
Conclusions : These data suggest that acute hyperglycaemia does not impair FMD in normal subjects.     

Association of coronary risk factors and endothelium-dependent flow-mediated dilatation of the brachial artery.

Impaired endothelial function has been reported to be the initial step in atherosclerosis. Some coronary risk factors independently relate to impaired endothelial function. However, few studies have examined the association between coronary risk factors and endothelial function in patients who have multiple risk factors without clinical atherosclerosis. This study was undertaken to elucidate the relationship between accumulation of coronary risk factors and vascular endothelial dysfunction. We examined 101 subjects with one or more coronary risk factors 56.8 +/- 1.0 years old and 40 age-matched control subjects without coronary risk factors. We measured brachial artery diameter non-invasively using a 7.5-MHz ultrasound machine at rest, during reactive hyperemia caused by endothelium-dependent vasodilatation, and after sublingual administration of nitroglycerin, which causes endothelium-independent vasodilatation. The percentage change in flow-mediated diameter (%FMD; deltaD/D x 100), in subjects with one or more coronary risk factors was significantly lower than that in control subjects(4.8 +/- 0.3% vs. 6.7 +/- 0.5%, p < 0.01). Endothelium-independent vasodilatation by nitroglycerin did not differ between the two groups. Endothelial function was impaired according to the accumulation of coronary risk factors. On multiple regression analysis, the number of risk factors, age, and brachial artery diameter at rest showed significant correlation with %FMD. Our results suggest that an accumulation of coronary risk factors was significantly related to impairment of endothelial function.     

Relationship between brachial artery flow-mediated dilatation, hyperemic shear stress, and the metabolic syndrome

Metabolic syndrome (MetSyn) may predispose to cardiovascular disease (CVD) by causing vascular dysfunction. This study aimed to determine the association of MetSyn with vascular function, as assessed by brachial artery flow-mediated dilatation (FMD) and hyperemic shear stress (HSS). A total of 1,417 male firefighters without established diabetes and CVD were classified for MetSyn, according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP) definition. MetSyn was present in 267 individuals (19%). Although FMD was lower in those with versus without MetSyn (8.1 +/- 4.1 vs 8.7 +/- 4.0%; p = 0.02), this was not significant after adjusting for baseline differences (age, smoking, and brachial artery diameter) (p = 0.2). However, HSS was significantly lower in those with versus without MetSyn (72.0 +/- 27.8 vs 80.9 +/- 24.8 dyne/cm(2); p < 0.001), and there was a significant inverse graded relationship with the number of NCEP criteria present (mean HSS for those with 0, 1, 2, 3, 4, and 5 criteria: 83.2 +/- 22.5, 82.2 +/- 24.7, 76.5 +/- 27.2, 74.3 +/- 27.4, 66.5 +/- 28.4, 67.1 +/- 27.6 dyne/cm(2); p < 0.001 for trend). The individual NCEP criteria of abdominal obesity, systolic hypertension, and impaired fasting glucose were independent predictors for HSS. In conclusion, MetSyn was not associated with impaired FMD. Alternatively, HSS, a measure of microvascular function, was significantly lower in those with MetSyn. Thus, MetSyn may contribute to CVD by causing microvascular dysfunction.     

Noninvasive assessment of endothelial dysfunction by brachial artery flow-mediated dilatation in prediction of coronary artery disease in Indian subjects

BACKGROUND: A noninvasive technique for testing endothelial function by ultrasound measurement of flow-mediated dilatation has recently generated considerable interest as a marker of atherosclerosis, and in the prediction of clinical coronary events and coronary artery disease. METHODS AND RESULTS: We measured the flow-mediated dilatation of the brachial artery (endothelium-dependent vasodilatation) in 136 subjects, with or without evidence of coronary artery disease. Endothelial dysfunction was diagnosed if flow-mediated dilatation was less than 4.5%. Of the 136 subjects (age group 40-70 years) recruited for the study, 94 were males and 42 females. Sixty-eight subjects had evidence of coronary artery disease as diagnosed by documented hospitalization due to myocardial infarction or acute coronary syndrome, proved by coronary angiography when feasible or noninvasive cardiac evaluation. Endothelial dysfunction was detected in 90 subjects (66.2%). Prevalence of coronary artery disease was higher among subjects with endothelial dysfunction compared to those without (57.5% v. 34.7%, p=0.013). Prevalence of endothelial dysfunction was significantly higher among subjects with coronary artery disease as compared to those without coronary artery disease (76.4% v. 55.8%, p=0.012). The present study showed a sensitivity of 76%, specificity of 44%, positive predictive value of 58% and negative predictive value of 65% for endothelial dysfunction in the prediction of coronary artery disease. Multiple regression analysis using coronary artery disease as a dependent variable revealed a statistically significant association with endothelial dysfunction (p=0.033) even after the inclusion of traditional risk factors into the model. CONCLUSIONS: We conclude that endothelial dysfunction shows a strong association with coronary artery disease and can be a useful noninvasive tool for the evaluation of coronary artery disease.     

Urinary albumin excretion is associated with impaired flow- and nitroglycerin-mediated brachial artery dilatation in hypertensive adults

We investigated whether the urinary albumin/creatinine ratio (UACR), a measure of albuminuria, is associated with non-invasive measures of arterial function in hypertensive adults without known coronary heart disease (CHD) or stroke. UACR was measured in the first voided morning urine sample in 469 non-Hispanic white hypertensive individuals (mean age 62.2+/-9.8 years, 41% men) belonging to hypertensive sibships. High-resolution ultrasonography of the brachial artery was used to assess flow-mediated dilatation (FMD)--an endothelium-dependent response--and nitroglycerin-mediated dilatation (NMD)--an endothelium-independent response. Because of skewed distribution, UACR was log transformed after addition of 0.1. The association of log (UACR+0.1) with FMD and NMD, before and after adjustment for CHD risk factors, serum creatinine, and hypertension medication and statin use was assessed using linear regression analyses. In univariable analyses, variables associated with lower FMD were greater age, male sex, history of smoking, lower high-density lipoprotein (HDL) cholesterol, higher serum creatinine and higher log (UACR+0.1); variables associated with lower NMD were greater age, male sex, higher systolic blood pressure, lower HDL cholesterol, higher serum creatinine and higher log (UACR+0.1). In separate stepwise multivariable regression analyses that adjusted for conventional CHD risk factors, serum creatinine and hypertension medication and statin use, higher log (UACR+0.1) was associated with lower brachial artery FMD (P=0.035) and NMD (P=0.0002). These findings highlight the association of increased urinary albumin excretion with impaired vascular reactivity in hypertensive individuals.     

Superficial brachial artery

Anomalies of the ramification of arteries in the upper extremity are an important consideration due to the large number of invasive procedures, both diagnostic and therapeutic, performed particularly in the cubital region of the upper limb. It is important for health professionals to be aware of arterial variation to prevent complications during diagnostic and therapeutic procedures. Here, we describe a rare unilateral anomaly of the brachial artery which courses subcutaneously through the right arm to the cubital region in a 75 year-old female patient.     

Brachial artery hyperaemic blood flow velocity and left ventricular geometry

Cardiovascular risk factors and carotid atherosclerosis relate to blood flow velocity in the brachial artery during induced hyperaemia. This relation proved to be particularly strong when using the hyperaemic systolic to diastolic blood flow velocity (SDFV) ratio. In this study, we further investigated this ratio in relation to the left ventricular (LV) geometry in a cross-sectional analysis. In the Prospective Investigation of the Vasculature in Uppsala Seniors study, 1016 seventy-year-olds participated. Blood flow velocity during hyperaemia of the brachial artery by Doppler was analysed. Echocardiography was performed, allowing analysis of LV geometry, categorised into four different groups: normal, concentric remodelling, concentric and eccentric hypertrophy. The SDFV ratio increased in subjects with concentric LV-remodelling (P=0.006) or LV-hypertrophy (P=0.001), but not in those with eccentric hypertrophy (P=0.12) when compared with the group with normal LV geometry. These associations remained significant after adjustment for gender, blood pressure, blood glucose, body mass index and antihypertensive treatment. The SDFV ratio in the brachial artery was related to concentric geometry of the LV in an elderly population sample, suggesting this new hemodynamic variable as a marker of increased afterload. Future studies have to determine if the SDFV ratio is a powerful predictor of future CV events, in addition to LV geometry.     

Long-term prognostic role of flow-mediated dilatation of the brachial artery after acute coronary syndromes without ST elevation

Coronary endothelial vasodilator dysfunction is associated with increased cardiac events; the close relation between coronary vasomotor dysfunction and brachial artery vasoreactivity has been previously described. This study assessed the prognostic value of noninvasively assessed brachial artery vasoreactivity in survivors of acute coronary syndromes without ST-segment elevation. We examined 98 men (63.1 +/- 10.8 years) who were referred to our hospital for acute coronary syndromes without ST-segment elevation. Brachial artery endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent nitrate-mediated dilation were examined in all patients using high-resolution echocardiographic Doppler ultrasound within 24 hours of admission. Plasma malondialdehyde, a marker of oxidative stress, and left ventricular ejection fraction were also assessed. Twenty-seven patients underwent coronary revascularization. Patients were followed for 24.8 +/- 5.9 months. Cardiovascular death, myocardial infarction, stroke, and unstable angina were designated as cardiovascular events (CEs). Twenty CEs were recorded. Kaplan-Meyer analysis showed that patients with FMD <1.9% (tertile 1 of FMD values) were more likely to have CEs than those with FMD >1.9% (log rank 5.29, p = 0.021). Multivariate Cox regression analysis showed that FMD <1.9% predicted CEs with an adjusted hazard ratio of 3.035 (95% confidence interval 1.148 to 8.023, p = 0.025) after adjustment for age, risk factors, troponin T, ejection fraction, revascularization procedures, number of diseased vessels, and medication. In conclusion, endothelium-dependent dilation of the brachial artery is a strong independent predictor of adverse outcome in survivors of acute coronary syndromes without ST-segment elevation.     

Effect of hyperhomocysteinemia induced by methionine administration on flow-mediated dilatation of the brachial artery in healthy subjects

Homocysteine may contribute to systolic hypertension and cardiac events by decreasing conduit artery compliance and inducing endothelial dysfunction. The effects of the experimental induction of hyperhomocysteinemia on systemic arterial compliance and pulsewave velocity are unclear, with contradictory results from previous studies. The investigators tested whether oral methionine impairs brachial artery compliance in addition to endothelial function.     

Congenital coronary artery dilatation

Although dilated coronary arteries are uncommon in children, three cases are presented which, even more unusually, were not associated with Kawasaki's disease     

Traumatic brachial artery injuries

We performed this retrospective study to analyze our strategies for managing and surgically treating brachial artery injuries. Fifty-seven patients with a total of 58 traumatic brachial artery injuries underwent surgery at our institution, from August 1996 through November 2004. Fifty-four patients were male and 3 were female (age range, 7 to 75 years; mean, 29.4 years). Forty-four of the patients had penetrating injuries (18 had stab wounds; 16, window glass injuries; and 10, industrial accidents), 10 had blunt trauma injuries (traffic accidents), and 3 had gunshot injuries. Fourteen patients (24.6%) had peripheral nerve injury. All patients underwent Doppler ultrasonographic examination. The repair of the 58 arterial injuries involved end-to-end anastomosis for 32 injuries (55.2%), reverse saphenous vein graft interpositional grafts for 18 (31%), and primary repair for 8 (13.8%). Venous continuity was achieved in 11 (84.6%) of 13 patients who had major venous injuries. Nine of the 57 patients (15.8%) required primary fasciotomy. Follow-up showed that 5 of the 14 patients with peripheral nerve injury had apparent disabilities due to nerve injury. One patient underwent amputation. There were no deaths. We believe that good results can be achieved in patients with brachial artery injuries by use of careful physical examination, Doppler ultrasonography, and restoration of viability with vascular repair and debridement of nonviable tissues. Traumatic neurologic injury frequently leads to disability of the extremities.     

Malignant brachial artery embolism

We present a rare case of malignant embolization of the brachial artery from a primary pulmonary tumor. The arterial embolism was the initial event in the clinical course of the disease. A review of the literature revealed forty three cases of malignant peripheral arterial embolism reported, and only two similar cases in which the embolization was the initial event of the disease.