The correlation between coronary stenosis index and flow-mediated dilation of the brachial artery

Impact of glycemic control on the association of endothelial dysfunction and coronary artery disease in patients with type 2 diabetes mellitus

Background

We investigated whether glycemic control affects the relation between endothelial dysfunction and coronary artery disease in patients with type 2 diabetes mellitus (T2DM).

Methods

In 102 type 2 diabetic patients with stable angina, endothelial function was evaluated using brachial artery flow-mediated dilation (FMD) with high-resolution ultrasound, and significant stenosis of major epicardial coronary arteries (≥ 50% diameter narrowing) and degree of coronary atherosclerosis (Gensini score and SYNTAX score) were determined. The status of glycemic control was assessed by blood concentration of glycated hemoglobin (HbA1c).

Results

The prevalence of significant coronary artery stenosis (67.9% vs. 37.0%, P = 0.002) and degree of coronary atherosclerosis (Gensini score: 48.99 ± 48.88 vs. 15.07 ± 21.03, P < 0.001; SYNTAX score: 15.88 ± 16.36 vs. 7.28 ± 10.54, P = 0.003) were higher and FMD was lower (6.03 ± 2.08% vs. 6.94 ± 2.20%, P = 0.036) in diabetic patients with poor glycemic control (HbA1c ≥ 7.0%; n = 56) compared to those with good glycemic control (HbA1c < 7.0%; n = 46). Multivariate regression analysis revealed that tertile of FMD was an independent determinant of presence of significant coronary artery stenosis (OR = 0.227 95% CI 0.056–0.915, P = 0.037), Gensini score (β =  − 0.470, P < 0.001) and SYNTAX score (β =  − 0.349, P = 0.004) in diabetic patients with poor glycemic control but not for those with good glycemic control (P > 0.05).

Conclusion

Poor glycemic control negatively influences the association of endothelial dysfunction and coronary artery disease in T2DM patients.

Effects of Intermittent Pneumatic Compression on Leg Vascular Function in People with Spinal Cord Injury: A Pilot Study

Objective: The purpose of this pilot study was to determine whether 60 mins of intermittent pneumatic compression therapy (IPC) could acutely increase leg blood flow-induced shear stress and enhance vascular endothelial function in persons with spinal cord injury (SCI). Design: Pretest with multiple posttests, within subject randomized control design. Setting: University of Southern Mississippi, Spinal Cord Injury Research Program within the School of Kinesiology, recruiting from the local community in Hattiesburg, Jackson, and Gulfport, MS. Participants: Eight adults with SCI (injury level: T3 and below; ASIA class A-C; age: 41±17 yrs). Interventions: A 60-min IPC session was performed in one leg (experimental leg; EXP), with the other leg serving as a control (CON). Outcomes Measures: Posterior-tibial artery shear rate (Doppler-ultrasound) was examined at rest, and at 15 and 45 mins during IPC. Endothelial function was assessed using the flow-mediated dilation (FMD) technique, before and after IPC. Results: Resting FMD (mm) was similar between legs at rest. A two-way repeated measures ANOVA (leg x time) revealed that during IPC, peak shear rate increased in the EXP leg (215±137 to 285±164 s^-1 at 15 mins; +39±29%, P = 0.03), with no change occurring in the CON. In addition, FMD significantly increased in the EXP leg (Pre IPC: 0.36±0.14 vs. Post IPC: 0.47±0.17 mm; P = 0.011, d = 0.66), with no change occurring in the CON leg. Conclusion: These preliminary findings suggests that IPC therapy may acutely increase leg shear stress within 15 mins, with a resultant moderate-large improvement in vascular endothelial function after 60 mins in people with SCI.

Impaired Flow-Mediated Dilation and Severity and Vulnerability of Culprit Plaque in Patients with Coronary Artery Disease

The association between endothelial function, evaluated using flow-mediated dilatation (FMD), and the severity of coronary artery disease remains to be elucidated.A total of 245 consecutive patients with stable angina were prospectively enrolled. FMD was evaluated in the brachial artery before percutaneous coronary intervention. Patients were divided into 2 groups according to the FMD value (lower FMD group [FMD < 2.0], n = 82; higher FMD group [FMD ≥ 2.0], n = 163). The severity of coronary artery disease was evaluated using findings of angiography and optical coherence tomography, and compared between the 2 groups.The prevalence of left main (LM) disease was significantly higher in the lower FMD group than in the higher FMD group (8.5% versus 2.5%, P = 0.046), although the prevalence of multivessel disease was comparable between the groups. Lower FMD was independently associated with a higher prevalence of LM disease (odds ratio, 3.89; 95% confidence interval, 1.12-15.5; P = 0.033). A general linear model with multiple variables revealed that the minimal lumen area (MLA) in the culprit lesion was significantly smaller in patients with lower FMD than in those with higher FMD (regression coefficient b, -0.249 mm²; 95% confidence interval, -0.479--0.018 mm²; P = 0.035). The prevalence ofvulnerable plaque characteristics was comparable between the 2 groups.Patients with lower FMD had a higher incidence of LM disease and a smaller MLA in the culprit lesion. FMD may be a useful, noninvasive indicator for identifying patients with severe coronary artery disease.

Impaired ability to grow colonies of endothelial stem cells could be the mechanism explaining the high cardiovascular morbidity and mortality of patients with depression

BACKGROUND

Subjects with depression are more prone to develop cardiovascular complications. Severity of depression is associated with higher rates of cardiovascular mortality and morbidity. Several mechanisms were suggested including accelerated atherosclerosis, alteration of the cardiac autonomic response with a decrease in heart rate variability. There is evidence that circulating endothelial progenitor cells (EPCs) are decreased in patients with major depression. Our hypothesis was that patients with depression would have an impaired ability to build colonies of EPCs.

METHODS

A prospective study enrolled twenty women with a diagnosis of major. All were not treated before for depression. Thirteen healthy age-matched women served as controls. All signed a consent form before recruitment to the study. Peripheral blood was drawn to build colonies of EPCs within 5 days. ELISA methods were used to measure levels of vascular cell adhesion molecule-1 (VCAM-1) and vascular endothelial growth factor (VEGF).

RESULTS

Twenty female patients with depression were recruited. The mean age was 43 ± 14 years (vs. controls 41 ± 11 years, P = 0.682), patients' average CFU-EPCs was 7 ± 8 colonies per well (controls 31 ± 11, P = 0.0001), VCAM-1 level was 121.7 ± 3.0 ng/ml (controls 119.3 ± 3.1 pg/ml, P = 0.037), VEGF level was 6.4 ± 0.2 pg/ml (controls 5.2 ± 0.5 pg/ml, P = 0.0001). An inverse correlation was found between VEGF level and EPCs' colonies (r  = -0.547, P < 0.001) and between age and CFU-EPCs (r = -0.576, P = 0.008).

CONCLUSIONS

We found that patients with major depression had high levels of VCAM-1 and VEGF. They also had a significant inhibition of EPCs' colonies. An inverse correlation was found between levels of VEGF and the ability to grow colonies of EPCs in culture.

Exercise mediated protection of diabetic heart through modulation of microRNA mediated molecular pathways

Hyperglycaemia, hypertension, dyslipidemia and insulin resistance collectively impact on the myocardium of people with diabetes, triggering molecular, structural and myocardial abnormalities. These have been suggested to aggravate oxidative stress, systemic inflammation, myocardial lipotoxicity and impaired myocardial substrate utilization. As a consequence, this leads to the development of a spectrum of cardiovascular diseases, which may include but not limited to coronary endothelial dysfunction, and left ventricular remodelling and dysfunction. Diabetic heart disease (DHD) is the term used to describe the presence of heart disease specifically in diabetic patients. Despite significant advances in medical research and long clinical history of anti-diabetic medications, the risk of heart failure in people with diabetes never declines. Interestingly, sustainable and long-term exercise regimen has emerged as an effective synergistic therapy to combat the cardiovascular complications in people with diabetes, although the precise molecular mechanism(s) underlying this protection remain unclear. This review provides an overview of the underlying mechanisms of hyperglycaemia- and insulin resistance-mediated DHD with a detailed discussion on the role of different intensities of exercise in mitigating these molecular alterations in diabetic heart. In particular, we provide the possible role of exercise on microRNAs, the key molecular regulators of several pathophysiological processes.

Intra- and interday reproducibility of high-flow-mediated constriction response in young adults

BACKGROUND

Previously, we have demonstrated that high-flow-mediated constriction (H-FMC) of the brachial artery has been shown to negatively affect flow-mediated dilation (FMD). However, the reproducibility of an H-FMC response is unknown.

OBJECTIVE

The aim of this study was to determine the intra- and interday reproducibility of H-FMC in young adults.

METHODS

Thirty young adults (15 male, 15 female; 24 ± 3 years) were assessed for H-FMC reproducibility via high-resolution ultrasound imaging of the brachial artery during and after forearm occlusion of a normal FMD procedure. Two vascular assessments were conducted for all participants during two separate visits with a minimum of 7 days in between. H-FMC was characterized as the greatest 10-s average constriction occurring after 3-s postocclusion compared to baseline brachial artery diameter and considered present if the percent change was <-0·1%.

RESULTS

Of the 120 total vascular assessments performed in this study, 98 of the assessments (80·3%) displayed an H-FMC. H-FMC diameter was not statistically different for intraday comparisons for visit 1 (P = 0·39) or visit 2 (P = 0·55) or interday comparisons between the first (P = 0·61) or second (P = 0·10) assessments. H-FMC percentage was also not statistically different for intra-day comparison for visit 1 (P = 0·94) or visit 2 (P = 0·15) or interday comparisons between the first (P = 0·63) or second (P = 0·16) assessments.

CONCLUSION

These data are supportive of H-FMC being reproducible in young adults and included in future FMD studies. The impact of H-FMC on future CVD risk and development warrants evaluation.

Low-flow mediated constriction: the yin to FMD's yang?

Given the prevalence of cardiovascular disease (CVD), early detection is crucial. Although traditional cardiovascular risk factors relate to future CVD, the predictive value of these risk factors can be relatively limited. Contemporary scientific attention has focused on alternative direct measures of arterial function. Based on the ability of the endothelium to acutely dilate in response to an increase in flow, 'flow mediated dilation' (FMD) was introduced approximately 20 years ago and is now an established non-invasive index of endothelial function predictive of future cardiovascular events. Recently, 'low-flow mediated constriction' (L-FMC) has been proposed as a complementary addition to FMD. The technique is based on the constrictor response to decreased flow and is claimed to improve the sensitivity and specificity of FMD. The aim of this review is to examine literature pertaining to this novel technique and to provide insight into the potential use of L-FMC in future research.

Low-volume, high-intensity interval training in patients with CAD

PURPOSE

Isocaloric interval exercise training programs have been shown to elicit improvements in numerous physiological indices in patients with CAD. Low-volume high-intensity interval exercise training (HIT) is effective in healthy populations; however, its effectiveness in cardiac rehabilitation has not been established. This study compared the effects of 12-wk of HIT and higher-volume moderate-intensity endurance exercise (END) on brachial artery flow-mediated dilation (FMD) and cardiorespiratory fitness (VO2 peak) in patients with CAD.

METHODS

Twenty-two patients with documented CAD were randomized into HIT (n = 11) or END (n = 11) based on pretraining FMD. Both groups attended two supervised sessions per week for 12 wk. END performed 30-50 min of continuous cycling at 58% peak power output (PPO), whereas HIT performed ten 1-min intervals at 89% PPO separated by 1-min intervals at 10% PPO per session.

RESULTS

Relative FMD was increased posttraining (END, 4.4% ± 2.6% vs 5.9% ± 3.6%; HIT, 4.6% ± 3.6% vs 6.1% ± 3.4%, P ≤ 0.001 pre- vs posttraining) with no differences between groups. A training effect was also observed for relative VO2 peak (END, 18.7 ± 5.7 vs 22.3 ± 6.1 mL · kg(-1) · min(-1); HIT, 19.8 ± 3.7 vs 24.5 ± 4.5 mL · kg(-1) · min(-1), P < 0.001 for pre- vs posttraining), with no group differences.

CONCLUSIONS

Low-volume HIT provides an alternative to the current, more time-intensive prescription for cardiac rehabilitation. HIT elicited similar improvements in fitness and FMD as END, despite differences in exercise duration and intensity.

Endothelial Dysfunction in Patients With Coronary Artery Disease

Background:

The use of flow-mediated dilation (FMD) as a surrogate indicator for the extent of coronary artery disease (CAD) remains largely unknown. We assessed FMD at the brachial artery in 89 consecutive patients undergoing coronary angiography.

Methods and Results:

Patients were classified in groups 0 to 3 according to the number of diseased vessels and the SYNTAX score was calculated. The FMD decreased significantly from groups 0 to 3 ( P < .001). There was a significant linear relation between SYNTAX score and FMD (corrected r2 = .64, P < .001). In multivariate analysis, a reduced FMD was the only significant independent predictor of the presence of CAD (odds ratio [OR] 1.78, P = .032) and of CAD severity (OR 1.85, P = .005).

Conclusion:

This study confirms that FMD is reduced in patients with CAD and that such reduction in FMD is related to the extent of the disease. Therefore, FMD at the brachial artery is likely to represent a reliable indicator of CAD burden.

Improvements in vascular health by a low-fat diet, but not a high-fat diet, are mediated by changes in adipocyte biology

Background

Low-fat (LF) and high-fat (HF) weight loss diets improve brachial artery flow-mediated dilation (FMD) in obese individuals, although results are conflicting. Moreover, the role that adipose tissue plays in mediating these diet-related effects are unknown.

Objective

This study examined how modulations in FMD by HF and LF diets relate to changes in adipocyte parameters.

Design

Obese subjects (n = 17) were randomized to a HF diet (60% kcal as fat) or a LF diet (25% kcal as fat) for 6 weeks. Both groups were restricted by 25% of energy needs.

Results

Body weight decreased (P <0.05) in both groups (HF: -6.6 ± 0.5 kg, LF: -4.7 ± 0.6 kg). Fat mass and waist circumference were reduced (P <0.05) in the LF group only (-4.4 ± 0.3 kg; -3.6 ± 0.8 cm, respectively). FMD improved (P <0.05) in the LF group (7.4 ± 0.8% to 9.8 ± 0.8; 32% increase) and was impaired in the HF group (8.5 ± 0.6% to 6.9 ± 0.7; 19% reduction). Increases in plasma adiponectin (P <0.05, 16 ± 5%), and decreases in resistin (P <0.05, -26 ± 11%), were shown by the LF diet only. Greater decreases in leptin were observed with LF (-48 ± 9%) versus HF (-28 ± 12%) (P <0.05, diet × time). Increased FMD by the LF diet was associated with increased adiponectin, and decreased fat mass, waist circumference, leptin, and resistin.

Conclusion

Beneficial modulations in vascular health by LF diets may be mediated by improvements in adipocyte parameters.

Brachial artery low-flow-mediated constriction is increased early after coronary intervention and reduces during recovery after acute coronary syndrome: characterization of a recently described index of vascular function

AIMS

The endothelium plays a role in regulating vascular tone. Acute and dynamic changes in low-flow-mediated constriction (L-FMC) and how it changes with regard to traditional flow-mediated dilatation (FMD) have not been described. We aimed to investigate the changes in brachial artery L-FMC following percutaneous coronary intervention (PCI) and during recovery from non-ST-segment elevation myocardial infarction (NSTEMI).

METHODS AND RESULTS

FMD was performed in accordance with a previously described technique in patients before and after PCI and in the recovery phase of NSTEMI, but in addition, L-FMC data were acquired from the last 30 s of cuff inflation. About 135 scans were performed in 96 participants (10 healthy volunteers and 86 patients). Measurement of brachial L-FMC was reproducible over hours. L-FMC was greater among patients with unstable vs. stable coronary atherosclerosis (-1.33 ±1.09% vs. -0.03 ± 1.26%, P < 0.01). Following PCI, FMD reduced (4.43 ± 2.93% vs. 1.66 ± 2.16%, P < 0.01) and L-FMC increased (-0.33 ± 0.76% vs. -1.63 ± 1.15%, P = 0.02). Furthermore, during convalescence from NSTEMI, L-FMC reduced (-1.37 ± 1.19% vs. 0.01 ± 0.82%, P = 0.02) in parallel with improvements in FMD (2.54 ± 2.19% vs. 5.15 ± 3.07%, P < 0.01).

CONCLUSION

Brachial L-FMC can be measured reliably. Differences were observed between patients with stable and unstable coronary disease. L-FMC was acutely increased following PCI associated with reduced FMD and, in the recovery from NSTEMI, L-FMC reduced associated with increased FMD. These novel findings characterize acute and subacute variations in brachial L-FMC. The pathophysiological and clinical implications of these observations require further study.

Flow-mediated dilatation has no independent prognostic effect in patients with chest pain with or without ischaemic heart disease

OBJECTIVE

The purpose of this study was to assess the prognostic effect of flow-mediated dilatation (FMD) in patients with chest pain admitted to a coronary care unit.

METHODS

Endothelium-dependent FMD in the brachial artery was examined in 223 patients with acute chest pain. All patients underwent a stress test at the time of admittance. On the basis of a positive stress test, a prior myocardial infarction (MI), prior percutaneous coronary intervention (PCI) or coronary bypass surgery (CABG), 137 patients were categorized as having ischaemic heart disease (IHD).

RESULTS

Patients with IHD had significantly lower FMD than patients without IHD (p=0.002). During a mean follow-up of 4.2 years, 90 patients had an endpoint event, i.e. cardiovascular death, acute MI, unstable angina pectoris, PCI or CABG. In univariate analysis, FMD <3 % was associated with an increased hazard of the combined endpoint (p=0.04). In multivariate analysis, adjusted for age, gender, IHD and body mass index, no association between FMD and the combined endpoint was found (p=0.99).

CONCLUSION

FMD is associated with IHD, but has no independent prognostic effect in patients with chest pain.

Assessment of subclinical atherosclerosis and cardiovascular risk

Conventional cardiac risk factors do not fully explain the incidence of coronary artery disease and coronary events. Risk stratification and therapy based solely on these conventional risk factors may exclude a population who would otherwise benefit from lifestyle and risk factor modification. Recent efforts to improve our ability to recognize individuals and populations at increased risk of coronary events have focused on the noninvasive imaging of atherosclerosis, both in coronary and extracoronary arterial beds, or the identification of "non-traditional" serum markers. We review the complimentary role of these newer methods of risk stratification in the context of conventional risk factor evaluation.

Endothelial dysfunction, carotid artery plaque burden, and conventional exercise-induced myocardial ischemia as predictors of coronary artery disease prognosis

Background

While both flow-mediated vasodilation (FMD) in the brachial artery (BA), which measures endothelium-dependent vasodilatation, and intima-media thickness (IMT) in the carotid artery are correlated with the prognosis of coronary artery disease (CAD), it is not clear which modality is a better predictor of CAD. Furthermore, it has not been fully determined whether either of these modalities is superior to conventional ST-segment depression on exercise stress electrocardiogram (ECG) as a predictor. Thus, the goal of the present study was to compare the predictive value of FMD, IMT, and stress ECG for CAD prognosis.

Methods and Results

A total of 103 consecutive patients (62 ± 9 years old, 79 men) with clinically suspected CAD had FMD and nitroglycerin-induced dilation (NTG-D) in the BA, carotid artery IMT measurement using high-resolution ultrasound, and exercise treadmill testing. The 73 CAD patients and 30 normal coronary patients were followed for 50 ± 15 months. Fifteen patients had coronary events during this period (1 cardiac death, 2 non-fatal myocardial infarctions, 3 acute heart failures, and 9 unstable anginas). On Kaplan-Meier analysis, only FMD and stress ECG were significant predictors for cardiac events.

Conclusion

Brachial endothelial function as reflected by FMD and conventional exercise stress testing has comparable prognostic value, whereas carotid artery plaque burden appears to be less powerful for predicting future cardiac events.

The association of homocysteine and related factors to brachial artery diameter and flow-mediated dilation

Brachial artery flow-mediated dilation (BAFMD) has been proposed as a measurement of the degree and severity of cardiovascular disease. The purpose of this study was to (1) evaluate the associations between BAFMD and homocysteine, folate, vitamin B(12), vitamin B(6); (2) examine the influence of 5,10-methylenetetrahydrofolate reductase (MTHFR) genotypes on homocysteine levels and BAFMD; and (3) evaluate the effect of homocysteine on the baseline diameter of the vessel vs BAFMD. A total of 174 healthy research subjects were examined for BAFMD, homocysteine, folate, vitamin B(12), vitamin B(6), and MTHFR genotype, nucleotide 677 C-->T. The data indicated a significant inverse correlation between homocysteine and BAFMD (r = -0.1763, P = .02). There was a significant difference in BAFMD between MTHFR genotype groups (P = .01) (T/T vs C/C, P = .042; C/C vs C/T, P = .13; T/T vs C/T, P = .003). Homocysteine was significantly associated with the baseline brachial artery diameter (r = 0.1878, P = .013). The data confirmed a significant inverse correlation between baseline diameter and BAFMD (r = -0.3321, P = .0001). Regression analysis indicated that the MTHFR genotype, homocysteine, and age were significant predictors of BAFMD (P = .0001, r(2) = 0.118). When the baseline brachial diameter was incorporated into the model, the effect of homocysteine on BAFMD disappeared. The present data indicate an association between homocysteine and BAFMD and reduced BAFMD in individuals with the MTHFR nucleotide 677 T/T genotype, despite similar blood values for folate and homocysteine. Finally, the data suggest that the effect of homocysteine on vascular reactivity is in part a consequence of its influence on baseline brachial artery diameter.

Comparative predictive and diagnostic value of flow-mediated vasodilation in the brachial artery and intima media thickness of the carotid artery for assessment of coronary artery disease severity

BACKGROUND

While recent reports suggest that both flow-mediated vasodilation (FMD) in the brachial artery (BA), endothelium-dependent vasodilatation, and intima media thickness (IMT) in the carotid artery correlate with the extent of coronary artery disease (CAD), it is not clear which modality is a better predictor for CAD severity and whether either of these modalities are superior to conventional ST-segment depression in exercise stress electrocardiogram (ECG). Thus, the goal of the present study was to compare the predictive value of FMD and IMT for CAD severity and to evaluate the diagnostic accuracy.

STUDY

A total of 103 consecutive patients (62+/-9 years, 79 men) with clinically suspected CAD underwent FMD and nitroglycerin-induced dilation (NTG-D) in the BA as well as measurement of carotid artery IMT by using high-resolution ultrasound, and exercise treadmill testing. Coronary stenosis index (CSI) was calculated from coronary angiography.

RESULTS

Seventy-three patients had significant CAD, and 30 patients showed no CAD (NL). FMD was significantly lower and IMT was significantly higher in patients with CAD compared with NL patients (FMD, 3.7+/-3.0% vs. 7.5+/-2.9%; IMT, 1.1+/-0.2 mm vs. 0.7+/-0.1 mm). FMD and IMT correlated to CSI to a similar degree (r=-0.67, r=0.69, respectively), and there was a significant correlation between FMD and IMT. In contrast, NTG-D did not correlate with CSI or IMT. Further, the diagnostic accuracy of FMD and IMT was comparable or even better than that obtained with conventional ST-segment depression during exercise in this cohort.

CONCLUSIONS

FMD in BA and IMT could represent a surrogate diagnostic method for assessment of CAD severity.

Biphasic responses of the brachial artery diameter following forearm occlusion: a blunted response in the elderly

Background

The purpose was to examine the temporal response of the brachial artery diameter following 5 minutes of forearm occlusion in young men. A secondary objective was to compare the main features of the temporal pattern between young and old.

Methods

Sixteen young (28 ± 8 yrs) and fifteen older (85 ± 8 yrs) men underwent high-resolution ultrasonography of the brachial artery before and after five minutes of forearm occlusion.

Results

Following release of the pressure cuff the brachial artery diameter exhibits a temporal biphasic response. Initially, there is a significant reduction in brachial diameter (NIL) compared to baseline (BASE), followed by a rapid increase to a PEAK at 41 sec post release. When comparing the magnitude of the decrease in diameter and the Brachial Artery Flow Mediated Dilation (BAFMD) between Young and Old, older subjects demonstrated a blunted response (Magnitude of Decrease: Young: 2.0%; Old: 0.4%, p = 0.015, and BAFMD: Young: 7.7%; Old: 2.3%, p = 0.001). Finally, a significant relationship was noted between the magnitude of decrease and BAFMD (r = -0.44, p = 0.04).

Conclusion

Examination of the temporal response of the brachial artery diameter following 5 minutes of forearm occlusion reveals a biphasic pattern in all participants. Specific features of this pattern are blunted in older adults compared with younger subjects. Finally, the magnitude of the drop in diameter following forearm occlusion correlates with the magnitude of the BAFMD.

Impaired Endothelial Function in Coronary Heart Disease Patients With Depressive Symptomatology

OBJECTIVES

The purpose of this study was to assess whether depressive symptomatology was associated with vascular endothelial dysfunction in patients with coronary heart disease (CHD).

BACKGROUND

In patients with CHD, the presence of depression is associated with a two to four times increased risk of mortality, but the disease pathways involved are uncertain. Endothelial dysfunction is an established risk factor for cardiovascular events in patients with CHD.

METHODS

Flow-mediated dilation (FMD) of the brachial artery, a measure of endothelial function, was assessed in 143 patients (99 men, 44 women), ages 40 to 84 years (mean age, 63 +/- 10 years), with documented CHD.

RESULTS

Patients with significant depressive symptomatology, as indicated by a Beck Depression Inventory (BDI) score > or = 10 (n = 47) showed attenuated FMD (p = 0.001) compared with patients that were not depressed (BDI < 10; n = 96). The use of antidepressant medication was associated with improved FMD (p < 0.05).

CONCLUSIONS

The increased risk of cardiovascular events in CHD patients with elevated symptoms of depression may be mediated, in part, by endothelial dysfunction.

Assessment of Arterial Stiffness Index as a Clinical Parameter for Atherosclerotic Coronary Artery Disease

BACKGROUND

The aim of the present study was to assess the feasibility and usefulness of the arterial stiffness index (ASI) measured non-invasively by computerized oscillometry and by comparing it with the pulse wave velocity (PWV).

METHODS AND RESULTS

The study group comprised 60 consutive patients who underwent coronary angiography and whose aorto-femoral PWV were obtained with a Judkins catheter. The ASI was obtained using Cardio Vision MS-2000 (IMDP, Las Vegas, NV, USA): (i) baseline (ASI-B); (ii) hyperemia induced by compression of the arm with cuff pressure for 5 min (ASI-H); and (iii) sublingual nitroglycerin (ASI-N). In total, 34 patients had significant coronary artery disease (CAD). The PWV and all ASI were higher in patients with CAD than in those without CAD (ASI-B, 85.9+/-57.8 vs 48.2+/-24.5, p=0.001; ASI-H, 98.1+/-49.8 vs 48.1+/-21.3, p<0.01; ASI-N, 66.7+/-55.7 vs 33.2+/-27.9, p=0.002). However, only ASI-B and ASI-H were positively correlated to the PWV (ASI-B, r=0.27, p=0.03; ASI-H, r=0.49, p=0.001; ASI-N, r=0.19, p=0.16). The ASI was increased after hyperemia in patients with CAD (ASI-H, 85.9+/-57.8 to 98.1+/-49.8, p=0.01), but not in patients without CAD (ASI-H, 48.2+/-24.5 to 48.1+/-21.3, p>0.01). After adjusting their age, only ASI-H was correlated to the presence of CAD (r=0.33, p<0.01).

CONCLUSIONS

It is feasible and useful to use the ASI for detection of atherosclerotic coronary disease. The findings of ASI-H suggests that in addition to stiffening of the arterial wall itself, the impairment of flow mediated vasodilation, because of endothelial dysfunction, further increases the arterial stiffness.

Assessment of flow-mediated vasodilatation (FMD) of the brachial artery: effects of technical aspects of the FMD measurement on the FMD response

AIMS

The ability to assess endothelial function non-invasively with B-mode ultrasound has lead to its widespread application in a variety of studies. However, the absolute values obtained using this approach vary considerably across studies. We studied whether technical aspects of the methodology can explain the wide variety in absolute values across studies.

METHODS AND RESULTS

A literature search was performed to identify published reports on flow-mediated vasodilatation (FMD) of the brachial artery published between 1992 and 2001. Information on type of equipment (wall track/B-mode), location of the measurement (antecubital fossa/upper arm), occlusion site (lower/upper arm), occlusion duration (min), and occlusion pressure was extracted. Patient characteristics were also extracted. For the healthy populations, mean FMD varied from 0.20 to 19.2%; for the coronary heart disease (CHD) patients FMD varied from -1.3 to 14%; for subjects with diabetes mellitus FMD varied from 0.75 to 12%. Compared with occlusion at the upper arm, lower arm occlusion was related to decreased FMD (mean difference in FMD -2.47%; 95% CI 0.55-4.39). An occlusion duration of > or =4.5 min was related to an increased FMD compared with an occlusion time of < or =4 min (mean difference 1.30%; 95% CI 0.35-2.46). These findings were adjusted for other technical aspects of the methodology and for differences in risk factors between populations.

CONCLUSION

Mean FMD differs widely between studies. There is a great overlap between populations (healthy, CHD, diabetics). Our findings suggest that the technical aspects of the measurements, the location, and the duration of the occlusion may explain some of these differences, whereas type of equipment, location of the measurement, and occlusion pressure do not.

Self-vasodilating ability at the spastic site of patients with vasospastic angina: estimation by acetylcholine delayed phase

Deficient nitric oxide (NO) release is thought to be the principal mechanism of coronary spasm, however, the precise mechanisms are unknown. Although acetylcholine (ACh) is used for provocation of coronary spasm, ACh is also used for the augmentation of blood flow and flow-mediated vasodilation is induced. We estimated the self-vasodilating ability (endothelial function) at the spastic site of coronary arteries in patients with vasospastic angina (VSA) during the provocation test of coronary spasm by ACh. This study included 93 patients with VSA and 77 patients with atypical chest pain (ACP). Intracoronary injection of ACh (20, 50, and 100 microg) was performed over 30 seconds and the coronary artery diameter of the spastic site was measured 3 to 4 minutes after ACh injection (delayed phase). The ability of dilation (AOD) was calculated as: ([diameter of delayed phase-baseline diameter]/[diameter after isosorbide dinitrate-baseline diameter]) x 100 (%). No significant difference was noted between the AOD in patients with ACP and VSA (28 +/- 36 vs 15 +/- 60%, respectively). The AOD values of 49% of patients with VSA were greater than the mean value of AOD of patients with ACP. At least almost half of the patients with VSA may have preserved self-vasodilating ability at the spastic site, and an abnormality other than endothelial dysfunction is involved in the mechanism of coronary spasm in these patients.

[Brachial artery flow-mediated dilation in healthy men, men with risk factors, and men with acute myocardial infarction. Importance of occlusion-cuff position]

INTRODUCTION AND OBJECTIVES

Flow-mediated dilation (FMD) is endothelium-dependent and can be assessed by ultrasound in the brachial artery. We sought to determine the most suitable position for the occlusion cuff for the study of FMD in three groups of adult men.

SUBJECTS AND METHODS

We included 160 subjects, mean age 58.5 7.8 years: 40 healthy subjects, 80 with cardiovascular risk factors, and 40 patients with AMI. In a subgroup of 60 subjects, the first 10, 30, and 20 of each group, respectively, FMD was evaluated twice, after upper arm occlusion and forearm occlusion to induce hyperemia.

RESULTS

In the initial substudy, the FMD after upper arm occlusion was 7.6 2.4% in healthy subjects, 5.1 2.2% in men with risk factors (p < 0.0001), and 3.5 2.2% in AMI patients (p < 0.041, with respect to the risk-factor group). FMD after forearm occlusion was 4.6 1.5%, 2.3 2.1% (p < 0.006), and 2.2 1.9%, respectively, with no significant statistical differences between the risk-factor and AMI groups. Only upper arm occlusion was performed in the remaining participants, as planned, because it provided the most accurate information. Overall, the FMD was, respectively, 7.8 3.1%, 5 2.6% (p < 0.0001) and 3.3 3% (p < 0.004, with respect to the risk-factor group). FMD was directly related to HDL cholesterol and inversely related to resting diameter and number of risk factors.

CONCLUSION

The best approach to studying FMD is proximal occlusion since it allows for a better stratification of the with endothelial dysfunction. With this technique, a worsening of endothelial function in acute myocardial infarction can be demonstrated.

Variability of flow mediated dilation: consequences for clinical application

BACKGROUND

Flow mediated vasodilatation (FMD), a non-invasive tool to assess endothelial function, has been shown to have prognostic value for the development of cardiovascular disease. Conventional B-mode ultrasonography has been criticised for its 'limited' resolution in vivo, which complicates reliable detection of the minute diameter changes during reactive hyperaemia. In the present study we evaluated the physical resolution, reproducibility and the capability to detect FMD impairment of a wall tracking system (WTS).

METHODS

The resolution of WTS was compared with that of intravascular ultrasound (IVUS) in pig femoral arteries in vivo. Subsequently, intra- and interobserver variability of FMD testing with WTS was evaluated in 75 healthy volunteers. Finally, the effect of smoking as single risk factor for atherosclerosis on FMD in vivo was assessed.

RESULTS

WTS and IVUS readings were not different (difference in arterial cross sectional area 1.97 mm(2), r=0.87). Intrasession coefficient of variation in baseline diameter was 1.1% (extremes 0.06--2.0%). Inter-session baseline diameter variation was 3.6 and 3.8% for each observer and 4.1% between observers. Intra-individual variability in FMD between sessions was considerable with coefficients of variation of 13.9% for FMD and 9.3% for NTG. Smokers had impaired FMD responses compared with matched non-smokers (4.7+/-2.4 vs. 9.6+/-4.4%, P<0.001), whereas NTG induced vasodilatation did not differ (13.4+/-6.2 vs. 15.4+/-5.1%; p=ns).

CONCLUSION

WTS is a suitable technique for reproducibly assessing the brachial artery diameter in vivo with a accuracy comparable to that of IVUS. Using this sensitive technique the reproducibility of FMD in vivo proves to be poor mainly due to physiological factors. Whereas this seriously limits the use of FMD as follow-up parameter for individual subjects, FMD is demonstrated to be a useful research tool at group level.

Ultrasound vasography evaluation of radial arterial grafts used for coronary arterial bypass surgery

OBJECTIVES

For coronary bypass surgery, radial arteries are often used as bypass grafts. Some of these arteries however, have arteriosclerotic lesions. We attempted to evaluate the relationship between arteriosclerosis and vasodilation.

METHODS

Prior to bypass surgery, 20 patients underwent ultrasound vasography to determine the condition of their radial and brachial arteries. Flow-mediated dilation, which is the same as endothelium-dependent vasodilation, was measured in the brachial artery of the nondominant arm by reactive hyperemia after 5-minute forearm ischemia. Vasodilation after application of a sublingual glyceryl trinitrate spray was also measured.

RESULTS

During surgery, 4 of 20 radial arteries demonstrated calcification, and 3 of the 4 could be used by removing the calcified part. However, the other artery, which had extensive calcification that could not be detected by ultrasound vasography, was discarded. The amount of vasodilation seen after the administration of sublingual glyceryl trinitrate had no correlation with calcified grafts. Calcified radial arteries demonstrated significantly poor brachial artery vasodilation by an endothelial-dependent vasodilation test.

CONCLUSIONS

Calcification in radial arteries can thus only be evaluated by flow-mediated dilation.

Tamoxifen effects on endothelial function and cardiovascular risk factors in men with advanced atherosclerosis

BACKGROUND

Tamoxifen and its analogues act as selective estrogen receptor modulators (SERMs) in women, with estrogen-like activities on some plasma cardiovascular risk factors (eg, lipoproteins). Effects of SERMs on men with coronary artery disease (CAD) have not been reported.

METHODS AND RESULTS

Thirty-one men with angiographically proven CAD were recruited; 16 were treated with tamoxifen (40 mg/d) for 56 days, and 15 were untreated. All the CAD patients were medicated with aspirin and an HMG-CoA reductase inhibitor for >/=6 weeks before entering the study. Ten men with angina-like symptoms but normal coronary arteries by angiography (NCA group) were also treated with tamoxifen. Blood samples were collected at days -7, 0, 7, 14, 21, 28, and 56 of treatment. Endothelium-dependent flow-mediated dilatation (ED-FMD) of the brachial artery was measured by high-resolution ultrasound at 5 visits. Tamoxifen caused an increase in %ED-FMD maximal at 28 days in the CAD group (2.1+/-0.3% to 7.5+/-0.7%; P<0.0001) and the NCA group (3.8+/-0.4% to 7.9+/-1.0%; P<0.0001), with no significant change in the untreated group. Tamoxifen also caused decreases in several plasma cardiovascular risk factors, including total cholesterol, triglycerides, lipoprotein(a), and fibrinogen. Except for the triglyceride response, these effects were similar to those reported for postmenopausal women treated with tamoxifen.

CONCLUSIONS

Tamoxifen substantially increased ED-FMD in men with CAD who were taking conventional medication. Together with the effects on risk factors, the data strongly support clinical evaluation of SERMs for the treatment of men with CAD.

Effects of troglitazone on frequency of coronary vasospastic-induced angina pectoris in patients with diabetes mellitus

This study investigates the effects of troglitazone, an insulin sensitizer, on the clinical manifestation of coronary vasospastic angina pectoris in patients with diabetes mellitus. Troglitazone reduces frequency of angina pectoris and improves endothelial function.