Biomedical subjects

Athanassios D Protogerou

Publications and source records attributed to Athanassios D Protogerou.

9 recordsLinked to original sources

PubMed2006

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.

Acute Disease↗

PubMed2006

Abnormal endothelial function in female patients with hypothyroidism and borderline thyroid function.

BACKGROUND: It has been suggested that hypothyroidism is associated with an increased risk for cardiovascular disease. The aim of this study was to assess non-invasively NO-dependent endothelial function of resistance arteries in subjects with hypothyroidism of varying severity. METHODS: Ninety-six female subjects (aged: 42+/-13 years) comprised the study population. Subjects were divided into five groups based on TSH levels at presentation: Group 0 (n=23) with TSH: 0.3-2.0 microU/ml, Group 1 (n=22) with TSH: 2.1-4.0 microU/ml (upper normal), Group 2 (n=18) with TSH: 4.1-10 microU/ml (subclinical hypothyroidism), Group 3 (n=22) with TSH >10 microU/ml (overt hypothyroidism). One additional group with well-controlled hypothyroidism on L-thyroxine therapy (Group 4, n=11, TSH: 0.3-2.0 microU/ml) was also studied. Endothelial function of resistance arteries was assessed by measuring forearm blood flow response during reactive hyperemia utilizing venous occlusion strain-gauge plethysmography. RESULTS: Duration of reactive hyperemia was significantly different among groups of subjects with varying hypothyroidism (83.7+/-58.3 s, 53.2+/-35.7 s, 52.8+/-47.5 s, 12.9+/-13.3 s and 69.5+/-26.2 s in Groups 0, 1, 2, 3 and 4, respectively, p<0.001, ANOVA). Duration of reactive hyperemia was significantly shorter in subjects with upper normal TSH values (Group 1) compared to controls (53.2+/-35.7 s vs. 83.7+/-58.3 s, p=0.013), while it was comparable to that of subjects with subclinical hypothyroidism (Group 2) (52.8+/-47.5 s). However, duration of reactive hyperemia in Group 1 was significantly longer compared to Group 3 (overt hypothyroidism) (53.2+/-35.7 s vs. 12.9+/-13.3 s, p=0.002). Similarly, duration of reactive hyperemia in subjects with subclinical hypothyroidism was significantly longer compared to subjects with overt hypothyroidism (52.8+/-47.5 s vs. 12.9+/-13.3 s, p=0.003). Duration of reactive hyperemia in Group 4 (well-controlled hypothyroidism on L-thyroxine therapy) did not differ significantly compared to controls. There was a highly significant linear correlation between duration of reactive hyperemia and TSH (r=-0.383, p<0.001). CONCLUSION: Endothelial dysfunction was detected in the microvasculature of patients with hypothyroidism. Duration of reactive hyperemia decreased with increasing TSH levels. Since endothelial dysfunction is a factor leading to atherosclerosis, this abnormality may partly explain predisposition of patients with thyroid failure to cardiovascular disease.

Adult↗

PubMed2006

Pressure wave reflections, central blood pressure, and aortic stiffness in patients with Adamantiades-Behcet's disease: a cross-sectional case-control study underlining the role of chronic corticosteroid treatment.

BACKGROUND: Adamantiades-Behcet's disease (ABD) is a multisystemic inflammatory/autoimmune disease involving both microcirculation and macrocirculation. Aortic stiffness index and aortic augmentation index (AI) are indices for the estimation of arterial stiffness and pressure wave reflections, respectively. The effect of anti-inflammatory and immunosuppressive drugs used in ABD on these indices is unknown. METHODS: In this cross-sectional study we examined 74 subjects with ABD (aged 40.1 +/- 12.5 years, 24 men) and 24 control subjects by using the noninvasive technique of radial artery applanation tonometry and pulse wave analysis for assessment of aortic AI by application of transfer functions. Echocardiography was used for assessment of aortic stiffness index. Classic cardiovascular (CV) risk factors, left ventricular and endothelial function of the brachial artery, as well as intima-media thickness of carotid artery, were also assessed. RESULTS: Corticosteroids were the only drug having a negative and independent effect on aortic AI, but not on aortic stiffness. Patients taking corticosteroids had lower aortic AI and central systolic blood pressure (BP), but not aortic stiffness and peripheral systolic BP, when compared to those without corticosteroids (21+/-14% v 12+/-14%, P < .050). Medication, traditional CV risk factors, and functional or structural CV parameters were all comparable among the two groups. The AI was similar between the control group and patients with ABD taking corticosteroids. CONCLUSIONS: The AI, but not aortic stiffness, is lower in patients with ABD taking corticosteroids compared to patients not taking corticosteroids and similar to the control group. These results imply a role of inflammation or immunomodulatory mechanisms in the regulation of pressure wave reflections.

Adrenal Cortex Hormones↗

PubMed2005

Transmission of calibration errors (input) by generalized transfer functions to the aortic pressures (output) at different hemodynamic states.

BACKGROUND: Aortic pressure waveforms are calculated non-invasively by applying generalized transfer functions (GTF) to tonometric radial pressure waveforms. Input errors mainly during acquisition and calibration of tonometric pressures are "transferred" to aortic pressure calculation. The present study aimed to quantify the proportion of specific input errors which is "transferred" by the GTFs in a wide range of hemodynamic conditions and for different error combinations in brachial systolic (SBP) and diastolic (DBP) blood pressure measurements. METHODS: Aortic pulse wave analysis was performed in 103 subjects (52 normotensive and 51 untreated hypertensive) by the SphygmoCor System. Each pressure waveform was initially calibrated by sphygmomanometrical brachial pressures. Isolated, parallel and reverse errors in brachial SBP/DBP from -10 to +10 mmHg were simulated, by recalibration of the recorded radial pressure waveforms, inducing specific "errors" of GTF-input values. For every recalculated aortic SBP and DBP, the difference from the initial estimated value was considered to represent the "transferred error" to the aortic pressure estimation. RESULTS: Parallel errors by +/-5 mmHg in both SBP and DBP resulted to an identical change in GTF-derived aortic pressures, as expected. When an overestimation in SBP by 5 mmHg and an underestimation in DBP by -5 mmHg occurred (reverse errors), almost 56% of this error (approximately 2.8 mmHg) was transferred. An isolated error in brachial SBP by +/-5 mmHg was transmitted by 76% ( approximately 3.8 mmHg) to GTF-derived aortic SBP. In subjects with mean blood pressure>117 mmHg or with heart rates<74 bpm, a greater percent of the calibration error was transferred to GTF-derived blood pressures. CONCLUSIONS: Input errors in brachial pressure values result in a quantifiable effect on transfer function output (aortic pressures). The percent of the "error transfer" by the GTFs depends on heart rate and BP levels, which should be taken into account when applying GTFs at populations with different hemodynamic conditions.

Adult↗

PubMed2005

Intima-media thickness score from carotid and femoral arteries predicts the extent of coronary artery disease: intima-media thickness and CAD.

OBJECTIVES: In the present study we measured carotid and femoral intima-media thickness (IMT) by B-Mode ultrasonography, as well as angiographic extent and severity of coronary artery disease in patients referred for coronary arteriography, to assess the relation between individual IMT, scores incorporating IMT from the carotid and femoral arteries and the extent and severity of coronary artery disease. METHODS: Two hundred and two patients referred for elective coronary angiography underwent ultrasound imaging of both carotid and femoral arteries for IMT measurements. An IMT score was developed as the number of sites with abnormal IMT (range 0-8). Multiple regression analysis indicated that IMT score was independently related to Gensini score, age and glucose levels. A high risk IMT score predicted an extended coronary artery disease although a low or medium risk IMT score cannot exclude the possibility of multivessel disease. Also, a high risk group could predict the performance of revascularization procedures and all cardiovascular events during a follow-up of 14.5 +/- 2.4 months. CONCLUSIONS: IMT incorporating data from common and internal carotid artery, carotid bifurcation and femoral artery are well correlated with the extent of coronary atherosclerosis, much better than individual IMT. Patients with high IMT score usually have multivessel coronary artery disease and are at increased risk for subsequent cardiovascular events.

Age Factors↗

PubMed2004

Cardiac hypertrophy in hypertension: relation to 24-h blood pressure profile and arterial stiffness.

BACKGROUND: In subjects with essential hypertension peripheral blood pressure profile contributes to the pathogenesis of left ventricular hypertrophy. It is not known if central arterial pressure is superior to peripheral blood pressure profile for predicting left ventricular hypertrophy. In the present study 24-h blood pressure profile and central hemodynamics were examined to evaluate mechanical loading factors as determinants of cardiac hypertrophy in mild to moderate untreated essential hypertension. METHODS: Forty-eight untreated subjects with mild to moderate essential hypertension were examined by echocardiography for evaluation of left ventricular mass, 24-h ambulatory blood pressure monitoring (ABPM), and applanation tonometry of the radial artery with pulse wave analysis for evaluation of central hemodynamics. RESULTS: Left ventricular mass showed a statistically significant correlation with age, clinic systolic blood pressure, mean heart rate and heart rate variability during 24-h ABPM, augmentation pressure and index and central systolic blood pressure. In a multiple regression analysis including clinic systolic blood pressure, central systolic pressure, mean systolic pressure and pulse pressure during ambulatory monitoring as well as age, independent predictors of left ventricular mass were only age (P=0.006) and central systolic blood pressure (P=0.04). In conclusion, pulse wave analysis is a valuable method in predicting cardiac hypertrophy in untreated mild to moderate essential hypertension. Central systolic blood pressure should be taken into account for planning therapeutic strategies for prevention of left ventricular hypertrophy in hypertensive patients.

Arteries↗

PubMed2004

Oral folic acid enhances endothelial function in patients with hypercholesterolaemia receiving statins.

BACKGROUND: Folic acid therapy has been shown to improve endothelial function in patients with familial hypercholesterolaemia via a possible antioxidant mechanism. Data on the possible role of folic acid in hypercholesterolaemic patients receiving statins are lacking. In the present study we tested the hypothesis that folic acid supplementation improves endothelial function in patients with hypercholesterolaemia and treatment with statins. METHODS: Thirty-four hypercholesterolaemic patients receiving statins participated in the study; all subjects underwent measurement of endothelium-dependent, flow-mediated dilatation of the brachial artery and subsequently randomized to receive 5 mg of the folic acid (n=17) or placebo (n=17) for 4 weeks. Flow-mediated dilatation of the brachial artery was repeated at the end of the 4-week period. RESULTS: Folic acid and placebo groups were comparable regarding age, sex, smoking, hypertension, coronary artery disease, obesity, family history and blood lipids. Folic acid administration resulted in an improvement of flow-mediated dilatation (4.7+/-3.2% to 7.1+/-3.1%, P=0.02), whereas there was no improvement after placebo administration (5.7+/-3.8% to 5.6+/-2.2%, ns). No significant change in nitrate-induced, endothelium- independent dilatation was observed after folic acid or placebo (ns). CONCLUSIONS: Oral administration of folic acid (5 mg) for 4 weeks improves endothelial function in patients with hypercholesterolaemia treated with statins, with possible beneficial effects on the prognosis of these patients.

Administration, Oral↗

PubMed2004

Effect of ascorbic acid on forearm reactive hyperaemia in patients with hypercholesterolaemia.

BACKGROUND: This study was designed to research the effect of hypercholesterolaemia and ascorbic acid on forearm blood flow (FBF) reactive hyperaemia (RH). Reactive hyperaemia seems to be at least partly endothelium-dependent. Endothelial dysfunction has been described in patients with hypercholesterolaemia, and has been reversed with ascorbic acid administration. METHOD: Forearm blood flow was studied with venous occlusion plethsmography in 26 healthy volunteers and 46 hypercholesterolaemic patients. Hypercholesterolaemic patients were divided into two groups. Group A comprised 25 patients, who received ascorbic acid and group B comprised 21 patients, who received placebo. All subjects underwent measurement of FBF at baseline and during RH (phase A). Forearm blood flow during RH was measured every 15 seconds for three minutes. Subsequently patients in group A received 2 g of ascorbic acid orally in the form of effervescent tablets, and patients in group B received placebo orally in the same form. Forearm blood flow measurements at baseline and during RH were repeated two hours later (phase B). RESULTS: Maximal percent increase of FBF was significantly higher in healthy subjects than in hypercholesterolaemic patients (139.1+/-12.1% versus 73.1+/-11.0% respectively, P<0.05). Duration of RH was smaller in hypercholesterolaemic patients compared to normal subjects (60.9+/-17.1 seconds versus 105.6+/-10.2 seconds, P<0.05). Administration of ascorbic acid but not of placebo increased the duration of RH (69.1+/-11.1 seconds versus 104.1+/-12.2 seconds, P<0.05) but not of peak RH FBF. CONCLUSION: Hypercholesterolaemia seems to impair both the early and late phase of RH. Ascorbic acid improves only the duration of RH, possibly due to its antioxidant effect on endothelium.

Adult↗

PubMed2004

Endothelial dysfunction and type of cigarette smoked: the impact of 'light' versus regular cigarette smoking.

Acute cigarette smoking leads to temporary endothelial dysfunction, which is an early event in atherogenesis. Sufficient data concerning the effect of cigarettes with low tar and nicotine yield are lacking. Seventeen healthy individuals (nine women, eight men, aged 27.8 +/- 3.6 years) were subjected to evaluation of endothelial function by means of endothelium-dependent, flow-mediated dilatation (FMD) of the brachial artery, before, immediately after and 30, 60 and 90 min after smoking a regular cigarette (nicotine 0.9 mg, tar 12 mg) orthe corresponding 'light' cigarette (nicotine 0.6 mg, tar 8 mg). The following day, measurements were repeated after smoking the opposite kind of cigarette. Baseline FMD was 6.1 +/- 1.6% and 7.2 +/- 2.0% in the light and regular cigarette groups, respectively (p = NS). The overall effect of the regular cigarette over time on FMD compared with the light cigarette was significantly different (F = 3.039, p = 0.023). FMD was significantly depressed after smoking both types (light: F = 8.192, p < 0.001; regular: F = 16.698, p < 0.001). Immediately after smoking, FMD declined in both groups (light: 3.0 +/- 2.4% and regular: 1.6 +/- 3.2%, p < 0.001 and p < 0.001, respectively), and it remained significantly depressed in the regular cigarette group at 30 min (0.75+/-1.5%, p < 0.001) and 60 min (3.5 +/- 3.1%, p = 0.024), while in the light cigarette group FMD differences were abolished at 30, 60 and 90 min after smoking. In conclusion, acute smoking of both regular and light cigarettes leads to temporary vasomotor dysfunction; its duration is shorter after smoking a 'light' cigarette.

Adult↗