Flow-mediated Vasodilation Testing Research Articles

Evaluation of endothelial dysfunction and inflammation in recovered COVID-19 patients

Aim: In our study, we aimed to evaluate the endothelial functions and hemogram parameters, which are considered as inflammation markers, in young people with a history of COVID-19 infection.
 Methods: This prospective study included 109 recovered COVID-19 patients and 50 healthy controls. Demographic characteristics, laboratory values and flow-mediated vasodilation test (FMD) results of the groups were compared.
 Results: Demographic and biochemistry parameters of the groups were similar. The calculated FMD values were significantly lower in the recovered COVID-19 patient group compared to the control group (8.66±3.31 vs 11.69±3.01; p= 0.001). While there was no difference between the groups in terms of neutrophil/lymphocyte ratio (NLR) and Platelet/Lymphocyte ratio (PLR), systemic immune-inflammation index (SII) was found to be higher in the patient group with recovered COVID-19 patients (p = 0.02). In correlation analysis, there was a low moderate negative correlation between FMD and SII (r = -0.35, p=0.002).
 Conclusion: FMD measurement and SII are simple, easily accessible parameters that can be useful in the early period to evaluate cardiovascular risks in the long term after COVID-19. There is a need for larger and multicenter studies on this subject.

Lower extremity vascular responses to preexercise intermittent passive stretch and treadmill exercise

Intermittent passive stretch induces local tissue hypoxia with subsequent increases in micro- and- macrovascular shear-rate, a powerful stimulus for nitric oxide generation in endothelial cells. Acute aerobic exercise stress has been associated with decreased endothelial function of the active limb. Whether intermittent passive stretch can reduce endothelial injury and improve endothelial function if performed before exercise has yet to be shown. This work investigated the impact of preexercise intermittent passive stretch on popliteal artery flow-mediated vasodilation (FMD) and the post occlusive reactive hyperemic (PORH) response within the gastrocnemius after aerobic exercise. We hypothesized that preexercise intermittent passive stretch of the calf muscles would prevent a decline in micro- and- macrovascular function after treadmill exercise. Sixteen healthy college-aged males and females participated in a single laboratory visit and underwent a PORH test with near-infrared spectrometry and FMD test to assess micro- and- macrovascular function. Participants were split into a PS group and a sham-control group performing minimal stretch. Intermittent passive calf stretching was performed by having participants place their foot in a splinting device for a 5-minute stretch, 5-minute relaxation period, repeated four times. Pre, post treatment, and post exercise time points were used in this investigation for analysis with a two-way repeated measures ANOVA and significance set at (P≤0.05). Following the treatment protocol, participants completed a VO 2 peak test to calculate 65% VO 2 peak and ran at this intensity for 30-minutes with post measurements taking place after a brief 10–20-minute recovery period. PORH with the NIRS revealed that microvascular responsiveness was preserved with the passive stretch group (pre: 0.053±0.009 %/s -1 ), (post: 0.051±0.013 %/s -1 ). There was a significant reduction (p=0.05) in the sham control group (pre: 0.072± 0.015 %/s -1 ), (post: 0.051±0.007 %/s -1 ) after treadmill exercise. Flow mediated vasodilation of the popliteal artery showed similar responses. In the passive stretch group, %FMD (pre: 7.58±0.88 %), (post: 6.40±1.21 %; p=0.27) and shear normalized FMD did not significantly decline after exercise (pre: 7.24 E-04 ±1.50 E-04 ), (post: 5.05 E-04 ±1.25 E-04 ; p=0.83). In the sham-control group %FMD (pre: 9.31±0.72 %), (post: 4.73±1.24 %; p<0.001) and normalized FMD were significantly reduced (pre: 1.06 E-03 ± 1.58 E-04 ), (post: 5.06 E-04 ±1.97 E-04 ; p<0.001). Passive stretch prior to acute exercise preserved popliteal artery endothelial function and gastrocnemius microvascular reperfusion. This vasoprotection was not shown in the sham-control group after acute exercise. Passive stretch is an easy low-cost method to maintain vascular function in the face of an acute exercise stress. Future work investigating adaptations to long term training when combined with preexercise stretch would be a valuable next step. University of Wisconsin- La Crosse Start up funds This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

THE RELATIONSHIP BETWEEN INFLAMMATION MARKERS AND MAGNESIUM/PHOSPHATE RATIO WITH ENDOTEL FUNCTION IN PERIPHERAL ARTERY DISEASE

Objective: In our study, it was aimed to evaluate the relationship between neutrophil/lymphocyte, monocyte/high-density lipoprotein and magnesium/phosphate ratios with endothelial functions in patients with peripheral artery disease. Methods: Sixty patients followed up with peripheral arterial disease were included in this study. Endothelial functions of the patients were evaluated by flow-mediated vasodilation test. Pearson correlation analysis was used to evaluate the relationship between magnesium/phosphate, neutrophil/lymphocyte, monocyte/high-density lipoprotein ratios with percent change in flow-mediated vasodilation. Results: 48.3% of the participants are male and 51.7% are female. The mean age of the patients were 66.85±11.08 years. The mean radial artery basal diameter was 0.24±0.02 cm in the flow-mediated vasodilatation test and after the test the mean radial artery diameter was 0.27±0.02 cm(p<0.001). In the flow-mediated dilatation test predicting endothelial functions, the percentage change in arterial diameter was positively correlated with the Magnesium/phosphate ratio (r=-0.326, p=0.011), and negatively correlated with the Neutrophil/lymphocyte ratio and monocyte/high-density lipoprotein ratio (respectively r= -0.411, p=0.001; r=-0.530, p=0.001). Conclusion: Magnesium/phosphate ratio, neutrophil/lymphocyte ratio and monocyte/high-density lipoprotein ratio can be used to predict endothelial dysfunction in patients with peripheral artery disease.

Preservation of Radial Vasomotor Functions Through the Anatomic Snuffbox: A Prospective Comparison with other Radial Accesses during Coronary Angiography.

To compare radial vasomotor functions at three different access sites namely right, left main radial artery, and left distal radial (LDR) artery. Observational study. Department of Cardiology, EGE University, Turkey, from September 2017 to February 2018. Forty-one patients scheduled for transradial elective coronary angiography and intervention were consecutively enrolled. Access site decision was left free to operators being blind of the study. Main radial vasomotor function measured through flow mediated vasodilation test was compared between other radial access sites on admission, 1 day and 2 months post-catheterisation. Five patients were intervened through the left main radial, whereas the LDR and the right main radial access were used in 17 and 19 patients respectively. In contrast to other radial access sites, LDR approach showed significantly less influenced vasomotor functions the day after the procedure. This feature continued to be preserved for two months of follow-up. Conclusion: Left distal radial branch in the anatomic snuffbox is a reliable access in terms of vasomotor function preservation compared to conventional left and right radial artery accesses. Key Words: Transradial access, Flow mediated vasodilatation, Endothelial function.6re6445.

Характеристика коронарного судинного русла, структурно-функціонального стану серця та ендотелійзалежної вазодилатації у хворих молодого віку з гострим коронарним синдромом з елевацією сегмента ST

The aim – to reveal features of the coronary vascular system, structural and functional state of the heart and endothelium-dependent vasodilatation in ST-elevation acute coronary syndrome (STEMI) patients of different age groups.Materials and methods. We analyzed the data of instrumental examination of patients who were admitted to the emergency departments from 2000 to 2015, with STEMI. Patients were distributed into two groups depending on age: 1 group – patients < 45 years, 2 group  45 years. Coronary angiography (CAG) was performed within the first hours after the admission. Endothelium-dependent, flow-mediated vasodilation (FMD) test and echocardiography were performed within 24 hours of admission and again on the 7th day.Results and discussion. According to сoronary angiography, elder patients were more likely to have infarction-dependent coronary artery disease (33.3 vs. 20.3 %; p=0.037), and multi-vessel coronary artery disease (12.0 vs. 4.8 %; p=0.048). Patients in the 1st group demonstrated a lower frequency of hemodynamically significant lesions of coronary vessels (p<0.001) and less marked disorders of the lipid spectrum. Patients of the group 1 had less thickness of the interventricular septum. 10.7±1.5 mm versus 11.6±1.6 mm, p=0.024). Young patients had initially better diastolic function (Е/А) (1.29±0.40 versus 1.00±0.52, p=0.008). At day 7 in patients of the 1st group there was a more marked increase in the left ventricularejection fraction and end-diastolic diastolic index of the left ventricle (7.6 versus 3.4 %; p<0.05) than in the patients of the 2nd group. Young patients demonstrated a tendency to increase of end-diastolic index > 10 %, in dynamics, at 39.7 versus 27.8 % elder patients (p=0.053), lower growth of the diameter of the brachial artery (4.7±4.1 vs. 6.7±5.1 %; p<0.05), but more rapid improvement of endothelial function in the dynamics of observation (104 vs. 23 %; p<0.05).Conclusions. The percentage of damage of coronary artery disease in STEMI young patients did not differ from elder patients but insignificant coronary artery stenosis is detected more often (р<0.001) and acute myocardial infarction in the right coronary artery is less common (р<0.037). Young patients with multi-vessel coronary disease have significant violations of the lipid blood spectrum (increased levels of total cholesterol, low density lipoprotein cholesterol). Indicators of intracardiac hemodynamic did not differ between age groups initially, however, the course of acute myocardial infarction in young patient was characterized by the tendency to develop early post-infarction dilatation (p=0.053). According to the FMD test young patients at the onset had a worse indicator of than elder patients (p<0.043), however the diameter of the brachial artery in the dynamics of observation, significantly increased (p<0.05).

Correlation of endothelial dysfunction measured by flow-mediated vasodilatation to severity of coronary artery disease

ObjectivesBrachial artery ultrasound imaging during reactive hyperemia is widely used tool for quantifying endothelium dependent vasomotion. Angiodefender device is used for non invasive determination of percentage flow mediated vasodilation (FMD). An attempt is made to study whether endothelial dysfunction determined by FMD of brachial artery predicts the presence or absence of coronary artery disease and its correlation with the severity of coronary artery disease. MethodsOne hundred six patients admitted between May 2014 and April 2015 who were posted for coronary angiography diagnosed to have chronic stable angina on clinical basis and/or by exercise stress test, for evaluation of coronary artery disease were submitted to standard clinical evaluation, calculation of percentage FMD by Angiodefender device. Statistical significance of difference of categorical variables was tested using Fisher’s exact test. Sensitivity, specificity, positive predictive value and negative predictive value of FMD were studied. ResultsThere was no correlation between number of risk factors and percentage of FMD. Significantly higher proportion of cases with less FMD had higher prevalence of coronary artery disease and vice-versa. Significantly higher proportion of cases with positive stress test had less percentage of FMD and vice-versa. Significantly higher proportion of cases with less percentage of FMD and positive stress test had higher prevalence of obstructive coronary artery disease and vice-versa. Specificity was 100% when percentage of FMD was ≤10. ConclusionsFMD an inexpensive and non-invasive test provides information regarding extent and severity of coronary artery disease.

Further Peripheral Vascular Dysfunction in Heart Failure Patients With a Continuous-Flow Left Ventricular Assist Device: The Role of Pulsatility

ObjectivesUsing flow-mediated vasodilation (FMD) and reactive hyperemia (RH), this study aimed to provide greater insight into left ventricular assist device (LVAD)–induced changes in peripheral vascular function. BackgroundPeripheral endothelial function is recognized to be impaired in patients with heart failure with reduced ejection fraction (HFrEF), but the peripheral vascular effects of continuous-flow LVAD implantation, now used as either a bridge to transplantation or as a destination therapy, remain unclear. MethodsSixty-eight subjects (13 New York Heart Association [NYHA] functional class II HFrEF patients, 19 NYHA functional class III/IV HFrEF patients, 20 NYHA functional class III/IV HFrEF patients post-LVAD implantation, and 16 healthy age-matched control subjects) underwent FMD and RH testing in the brachial artery with blood flow velocity, artery diameters, and pulsatility index (PI) assessed by ultrasound Doppler. ResultsPI was significantly lower in the LVAD group (2.0 ± 0.4) compared with both the HFrEF II (8.6 ± 0.8) and HFrEF III/IV (8.1 ± 0.9) patients, who, in turn, had significantly lower PI than the control subjects (12.8 ± 0.9). Likewise, LVAD %FMD/shear rate (0.09 ± 0.01 %Δ/s−1) was significantly reduced compared with all other groups (control subjects, 0.24 ± 0.03; HFrEF II, 0.17 ± 0.02; and HFrEF III/IV, 0.13 ± 0.02 %Δ/s−1), and %FMD/shear rate significantly correlated with PI (r = 0.45). RH was unremarkable across groups. ConclusionsAlthough central hemodynamics are improved in patients with HFrEF by a continuous-flow LVAD, peripheral vascular function is further compromised, which is likely due, at least in part, to the reduction in pulsatility that is a characteristic of such a mechanical assist device.

Evaluation of antithrombotic effect: Importance of testing components and methodologies.

The beneficial antithrombotic effect of some dietary components may offer the most promising approach of prevention of cardiovascular diseases and arterial thrombosis. The major stumbling block in finding effective dietary components is the lack of physiologically relevant techniques which can detect potential antithrombotic effect in humans. The presently used platelet function and coagulation tests do not allow the assessment of global thrombotic status and their value in screening dietary components for antithrombotic effect is questionable. Most of these in vitro tests ignore the effect of flow and shear stress, thrombin generation and vascular endothelium, the major contributors to arterial thrombogenesis in humans. As a gold standard, we employed the helium-neon (He-Ne) laser-induced thrombosis test in murine carotid artery and mesenteric microvessels, as the pathomechanism of this test closely reflects arterial thrombogenesis in humans. Results obtained with laser thrombosis test were compared with various shear-induced in vitro platelet function tests which use native blood (Haemostatometry, Thrombotic Status Analyser, Global Thrombosis Test-GTT). Contribution of vascular endothelium to thrombogenesis was assessed by measuring flow-mediated vasodilation (FMV) in vivo. The combination of the two shear-induced ex vivo thrombosis tests (Haemostatometry and GTT) with FMV correlated most closely with the laser-thrombosis test. Our findings suggest that combining the commercially available point-of-care GTT with the FMV test could provide a better assessment of the overall thrombotic status than either of the two tests alone.

The Effects of Continuous‐flow Left Ventricular Assist Devices on Peripheral Vascular Function

Peripheral endothelial function is known to be impaired in patients with heart failure (HF), but the vascular effects of continuous‐flow left ventricular assist device (LVAD) implantation, now employed as either a bridge to transplantation or as destination therapy, remain unclear. Using flow‐mediated vasodilation (FMD) and passive leg movement, this study aimed to provide greater insight into LVAD‐induced changes in vascular function. 8 healthy age‐matched controls (61 ± 3 yrs), 10 HF patients (61 ± 2 yrs), and 12 LVAD patients (57 ± 3 yrs) underwent FMD testing of the brachial artery and passive leg movement‐induced hyperemia assessment, with blood flow velocity and artery diameters assessed by ultrasound Doppler. FMD was significantly lower in HF (4.7 ± 0.7%) compared to the healthy controls (7.1 ± 1.2%) and lower than both of these groups in the LVAD patients (2.7 ± 0.8%). The change in leg blood flow from baseline to peak during passive movement followed a similar pattern. The hyperemic response in patients with HF was significantly attenuated compared to the controls (90 ± 9%Δ and 160 ± 27%Δ, respectively) and the response in the LVAD patients was significantly lower than both groups (45 ± 10%Δ). These results suggest that despite circulatory assistance, peripheral vascular function and hemodynamic regulation are attenuated in patients following LVAD implantation.

Mechanism of the experimental antithrombotic effect of some apple varieties involves enhanced endogenous thrombolytic activity

Abstract Prevention of arterial thrombotic diseases has high priority in developed countries. As inappropriate diet is known to enhance the risk for acute thrombotic events, a regular diet with experimentally proven antithrombotic effect might be a beneficial way of prevention. The present study is part of a series of investigations testing fruits and vegetables for antithrombotic activity. The Global Thrombosis Test was used to screen sixteen different apple varieties for antiplatelet and thrombolytic activities. The in vitro effective varieties were further investigated using the laser-induced thrombosis model in mice. In order to investigate the mechanism, hemostatometry and flow-mediated vasodilation test (FMV) were performed. Apple varieties were grouped into subclasses according to their antithrombotic activity. AP-2, AP-13, AP-14 and AP-15 showed significant antithrombotic effect both in vitro and in vivo. AP-8 was antithrombotic in vitro but could not determine in vivo because of the shortage of the sample. The antithrombotic effect was mainly due to activation of endogenous thrombolytic mechanism. The mechanism of such enhanced thrombolysis was investigated using a synthetic inhibitor highly specific to plasmin, polyclonal IgG to t-PA and u-PA, and testing the antithrombotic effect in t-PA knockout mice. Antithrombotic activity was prevented by the synthetic plasmin inhibitor and IgG against t-PA but not against u-PA. There was no antithrombotic activity in t-PA knockout mice. Intake of antithrombotic apple filtrate did not affect FMV and platelet reactivity. The antithrombotic effect was heat stable at 100 °C for 10 min. These results suggest that the mechanism of antithrombotic activity involves an increased t-PA release from the vascular endothelium and an inhibition of plasminogen activator inhibitor (PAI-1) release from activated platelets. The present findings justify including antithrombotic apple varieties in an antithrombotic diet.

Vascular function and the role of oxidative stress in heart failure, heart transplant, and beyond.

Using flow-mediated vasodilation (FMD), reactive hyperemia, and an acute oral antioxidant cocktail (AOC; vitamins C and E and α-lipoic acid), this study aimed to provide greater insight into altered vascular function and the role of oxidative stress in chronic heart failure patients with reduced ejection fraction (HFrEF) and at several time points beyond heart transplantation (HTx). A total of 61 age-matched subjects (12 healthy controls, 14 New York Heart Association class II and III HFrEF, and 35 HTx recipients [<3 years post-HTx, 5-10 years post-HTx, and >14 years post-HTx]) ingested either placebo (PL) or an AOC before FMD and reactive hyperemia testing of the brachial artery. Vascular function, as measured by FMD, was not different among the controls (6.8±1.9%), recent <3-year post-HTx group (8.1±1.2%), and the 5- to 10-year post-HTx group (5.5±1.0%). However, PL FMD was lower in the HFrEF (4.5±0.7%) and in the >14-year post-HTx group (2.9±0.8%). The AOC increased plasma ascorbate levels in all of the groups but only increased FMD in the controls (PL, 6.8±1.9%; AOC, 9.2±1.0%) and >14-year post-HTx recipients (PL, 2.9±0.8%; AOC, 4.5±1.3%). There were no differences in reactive hyperemia in any of the groups with PL or AOC. This cross-sectional study reveals that, compared with controls, vascular function is blunted in HFrEF, is similar soon after HTx, but is decreased with greater time post-HTx with free radicals implicated in this progression.

Vascular Function And Oxidative Stress: In Health, Heart Failure, Heart Transplantation, And Beyond

Vascular endothelial dysfunction is a systemic pathology that impairs the health and vasomotor control of both conduit and resistance vessels and has been linked to oxidative stress. Impaired endothelium-dependent vasodilation has been associated with various cardiovascular diseases including hypertension, coronary artery disease, and chronic heart failure (CHF), but more importantly may also precede the development of these conditions. PURPOSE: Using flow-mediated vasodilation (FMD) and reactive hyperemia (RH) of the brachial artery; this study aimed to provide greater insight into the changes in vascular function with the development of CHF, and as time passes following heart transplant (HTx) surgery. Additionally, we sought to determine if vascular function can be improved in these populations with an acute oral antioxidant cocktail (AOC (Vit C, E + α lipoic acid)) directly documented by electron paramagnetic resonance spectroscopy to reduce free radical concentration. METHODS: In a balanced design, 12 healthy age-matched controls (60 ± 4 yrs), 8 CHF patients (Class II-IV) (59 ± 3 yrs), 11 recent (< 3 yrs) HTx recipients (57 ± 3 yrs), and 6 (> 3yrs) HTx recipients (63 ± 4 yrs), ingested either a placebo (PL) or AOC prior to FMD and RH testing using ultrasound Doppler. RESULTS: Baseline vascular function, as measured by PL FMD, was not different between the controls (6.0 ± 0.9 %), CHF patients (6.2 ± 1.1%), and early HTx group (< 3 yrs) (8.8 ± 1.3%) but was lower in the (> 3 yrs) HTx recipients (4.2 ± 1.1%). The antioxidant intervention increased FMD in the controls (PL 6.0 ± 0.9%; AOC 8.8 ± 1.1%) and in the HTx recipients (> 3 yrs) (PL 4.2 ± 1.1%; AOC 7.3 ± 1.3%). RH was invariant across groups with and without the AOC. CONCLUSION: These data suggest that vascular function declines as time passes following HTx surgery and that oxidative stress is likely a key player in this process.

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

BackgroundWhile 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 ResultsA 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.ConclusionBrachial 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.

Long-term intake of rosemary and common thyme herbs inhibits experimental thrombosis without prolongation of bleeding time

Objective Our earlier study demonstrated an inhibition of experimental thrombogenesis after acute administration of rosemary and common thyme. The present study aimed to investigate the effect of long-term intake of these herbs on platelets, thrombus formation and bleeding time. Methods Western-style high-fat diet containing 5% or 0.5% dried rosemary or common thyme was given to male 6 week old C57BL/6 mice for 12 weeks. Shear-induced platelet reactivity was measured in vitro by haemostatometry. The antithrombotic effect was assessed by the laser-induced thrombosis technique in the carotid artery of mice. Bleeding time was tested by the tail cut method. Endothelial function was assessed by the flow-mediated vasodilation test. Results Rosemary (5% and 0.5%) significantly inhibited arterial thrombus formation. Only the higher concentration of common thyme (5%) had a significant antithrombotic effect. In 5% concentration, both rosemary and common thyme significantly inhibited platelet reactivity and enhanced the flow-mediated vasodilation. Conclusions Long-term daily intake of rosemary and common thyme has an antithrombotic effect, which is probably due to inhibition of platelets and stimulation of endothelial cells. The antithrombotic effect was not accompanied by prolongation of bleeding time.

Mechanism of the Antithrombotic Effect of Dietary Diacylglycerol in Atherogenic Mice

Introduction: We have shown earlier that diacylglycerol (DAG) but not triacylglycerol (TAG) inhibited thrombus formation. The aim of the present study was to investigate the mechanism of this antithrombotic effect of DAG. Materials and Methods: Four different diets, the (1) Western-style high-fat diet (HFD) containing 20% lipid and 0.05% cholesterol (w/w), (2) TAG-rich and (3) DAG-rich HFDs containing 20% lipid and 0.05% cholesterol, but all lipid replaced by TAG or DAG oil with very similar fatty acid composition and the (4) Japanese-style low-fat diet (LFD) containing 7% oil but no cholesterol were given to apolipoprotein E and low-density lipoprotein (LDL) receptor double-deficient mice. Atherogenicity was assessed by morphology, mapping the whole aorta and measuring the total area of lipid-stained lesions. Endothelial function was measured by the flow-mediated vasodilation test. Platelet reactivity was assessed from native blood sample by a shear-induced platelet function test (hemostatometry). Serum lipoprotein profile was measured by HPLC. Results: Both the Western-style and the TAG-rich HFDs have accelerated atherosclerosis. In contrast, DAG-rich HFD inhibited the atherosclerotic process to an extent comparable with the Japanese-style LFD. There was no significant difference in platelet and coagulant activity between the studied diet groups. DAG-rich but not the TAG-rich HFD significantly suppressed serum LDL cholesterol level. Conclusions: The present findings suggest that the mechanism of antithrombotic and anti-atherogenic effect of DAG may involve the protection of the vascular endothelium from injury and lowered serum LDL cholesterol.

Peripheral vascular endothelial function testing for the diagnosis of coronary artery disease

Background Abnormalities in endothelium-dependent vasodilation may be detected in arteries before the development of overt atherosclerosis, and their presence may predict stress-induced ischemia as assessed by ST-segment depression and/or perfusion defects. Brachial artery ultrasound during reactive hyperemia is a noninvasive method of assessing peripheral vasomotion, measured by flow-mediated vasodilation (FMD). The purpose of the current study was to assess whether endothelium-dependent FMD of the brachial artery, by ultrasound imaging, predicts the presence of angiographically assessed coronary artery disease (CAD). Methods One hundred ninety-eight in-hospital patients (age, 59 ± 9 years; 78 women) with chest pain syndrome and without previous myocardial infarction or revascularization procedures were enrolled in the present study. All of the patients, at testing time, were not receiving nitrate therapy and underwent, on different days, coronary angiography and endothelium-dependent FMD testing of the brachial artery by high-resolution ultrasound. The result of the flow-mediated dilation (%FMD) is defined as the percent change in the internal diameter of the brachial artery during reactive hyperemia related to baseline. A coronary vessel was considered to have a significant obstruction if its diameter was narrowed by 50% or more on quantitative computer-assisted analysis. A prognostically validated angiographic Duke score (from 0 = normal to 100 = severe left main disease) was calculated. Results The %FMD was lower in patients with (n = 69) compared with those without (n = 129) CAD (4.64% ± 4.36% vs 7.39% ± 5.68%; P = .01). By multivariate analysis, the %FMD ( P = .01; odds ratio [OR], 1.13; 95% confidence interval [CI], 1.05 to 1.23), male sex ( P = .01; OR, 3.47; 95% CI, 1.64 to 7.36), and cigarette smoking habit ( P < .01; OR, 4.00; 95% CI, 2.50 to 6.35) were independent predictors of CAD. %FMD was poorly albeit significantly correlated with the severity of CAD (%FMD Duke score, P < .01, r = −0.25). The receiver operator characteristic curve showed the %FMD optimal cutoff value as ≤8.84, with sensitivity of 90%, specificity of 37%, negative predictive value of 90%, and positive predictive value of 43%. Conclusions In patients with chest pain, a depressed FMD of the brachial artery was a sensitive indicator of CAD, but it showed poor specificity, and it appeared to be unable to predict both the extent and the severity of angiographically assessed CAD.