Dogan Erdogan

Relationship of serum uric acid to measures of endothelial function and atherosclerosis in healthy adults

Although uric acid (UA) is considered as an antioxidant, the relationship between serum UA levels and cardiovascular diseases is not clear yet. Higher brachial artery resting diameter (BD), impaired brachial artery flow‐mediated dilatation (FMD), increased carotid intima‐media thickness (IMT), decreased aortic distensibility (AoD), and increased aortic stiffness index (AoSI) and elastic modulus (AoEM) are predictors for development and/or progression of atherosclerosis. In this study, BD, FMD, carotid IMT, AoD, AoSI and AoEM were studied in healthy subjects with UA concentrations in physiological range.

N-acetylcysteine for the prevention of postoperative atrial fibrillation: a prospective, randomized, placebo-controlled pilot study

AIMS Oxidative stress has recently been implicated in the pathophysiology of atrial fibrillation (AF). The aim of the present study was to evaluate the effects of antioxidant agent N-acetylcysteine (NAC) on postoperative AF. METHODS AND RESULTS The population of this prospective, randomized, double-blind, placebo-controlled study consisted of 115 patients undergoing coronary artery bypass and/or valve surgery. All the patients were treated with standard medical therapy and were randomized to NAC group (n = 58) or placebo (saline, n = 57). An AF episode >5 min during hospitalization was accepted as endpoint. During follow-up period, 15 patients (15/115, 13%) had AF. The rate of AF was lower in NAC group compared with placebo group (three patients in NAC group [5.2%] and 12 patients in placebo group [21.1%] had postoperative AF; odds ratio [OR] 0.20; 95% confidence interval [CI] 0.05 to 0.77; P = 0.019). In the multivariable logistic regression analysis, independent predictors of postoperative AF were left atrial diameter (OR, 1.18; 95% CI, 1.06-1.31; P = 0.002) and the use of NAC (OR, 0.20; 95% CI, 0.04-0.91; P = 0.038). CONCLUSION The result of this study indicates that NAC treatment decreases the incidence of postoperative AF.

Effects of Normal Blood Pressure, Prehypertension, and Hypertension on Coronary Microvascular Function

Background— The assessment of coronary flow reserve (CFR) by transthoracic Doppler echocardiography has recently been introduced into clinical practice, and reduced CFR has been suggested to be a sensitive indicator of hypertensive end-organ damage; however, to date, this methodology has not been used to evaluate CFR in subjects with prehypertension. Accordingly, the present study was designed to evaluate CFR in subjects with prehypertension. Methods and Results— We measured CFR of 40 subjects with prehypertension, 60 patients with hypertension, and 50 normotensive healthy volunteers using transthoracic Doppler echocardiography. None of the subjects had any systemic disease. Age, gender, body mass index, heart rate, lipid profiles, fasting glucose levels, and hemoglobin were similar among the 3 groups. CFR was significantly lower in the hypertension group than in the prehypertension and control groups; in addition, it was significantly lower in subjects with prehypertension than in control subjects (2.23±0.47, 2.54±0.48, and 2.91±0.53, respectively). Furthermore, we found that prehypertension (β=−0.31, P<0.01) and hypertension (β=−0.57, P<0.01) were significant predictors of lower CFR in a multivariable model that adjusted for other variables. CFR was significantly and inversely correlated with age (r=−0.20, P=0.01), systolic blood pressure (r=−0.51, P<0.01), diastolic blood pressure (r=−0.47, P<0.01), high-sensitivity C-reactive protein levels (r=−0.21, P=0.01), left atrium diameter (r=−0.22, P<0.01), mitral E deceleration time (r=−0.19, P=0.02), and mitral A velocity (r=−0.27, P<0.01), whereas mitral E/A ratio was significantly and positively correlated with CFR (r=0.26, P<0.01). Conclusions— CFR is impaired in subjects with prehypertension, but this impairment is not as severe as that in hypertension.

High Serum Bilirubin Concentrations Preserve Coronary Flow Reserve and Coronary Microvascular Functions

Background—Elevated serum bilirubin concentrations protect against atherosclerotic diseases; however, it is not clear whether higher serum bilirubin concentrations in physiological ranges work in favor of the cardiovascular system in younger persons with no cardiovascular risk factors. Accordingly, we investigated the effects of high, intermediate, and low serum bilirubin concentrations on coronary flow reserve (CFR). Methods and Results—Fifty-two healthy subjects with hyperbilirubinemia (total bilirubin 1.43±0.33 mg/dL; mean age 35.9±7.3), 55 subjects with intermediate bilirubin level (total bilirubin: 0.69±0.11 mg/dL; mean age: 36.4±6.8), and 53 healthy subjects with hypobilirubinemia (total bilirubin 0.37±0.08 mg/dL; mean age, 37.6±6.6) were studied. Transthoracic second harmonic Doppler echocardiography examination was performed using an Acuson Sequoia C256 Echocardiography System. Coronary diastolic peak flow velocities were measured at baseline and after dipyridamole infusion (0.84 mg/kg over 6 minutes). CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocities. Demographic features, coronary risk factors, echocardiographic measurements, and biochemical measurements were similar among the 3 groups, except high-sensitivity C-reactive protein (hsCRP). CFR values were significantly higher in subjects with high bilirubin concentrations than those were in the intermediate and the low bilirubin groups (3.19±0.73; 2.75±0.42; 2.56±0.52, respectively; P<0.0001), and hsCRP levels were significantly lower in subjects with high bilirubin concentrations than those in both intermediate and low bilirubin groups (1.4±1.0, 2.0±1.7, 3.0±1.9 mg/L, respectively; P<0.001). hsCRP levels correlated with total bilirubin concentration and with CFR. Conclusion—Elevated serum bilirubin concentrations protect from CFR impairment, coronary microvascular dysfunction, and possibly coronary atherosclerosis.

Impaired Coronary Flow Reserve in Hemodialysis Patients: A Transthoracic Doppler Echocardiographic Study

Background: Coronary flow reserve (CFR) reflects the functional capacity of microcirculation to adapt to blood demand during increased cardiac work. In this study, CFR of hemodialysis patients with angiographically normal coronary arteries was evaluated using transthoracic second harmonic Doppler echocardiography. Methods and Results: Ten hemodialysis patients, and 14 sex-, age- and left ventricular mass index-matched hypertensive controls with angiographically normal coronary arteries underwent transthoracic second harmonic Doppler echocardiographic examination. Coronary basal diastolic peak flow velocities and hyperemic peak flow velocities after dipyridamole infusion (0.56 mg/kg over 4 min) were measured. CFR was defined as the ratio of hyperemic to basal diastolic peak velocities. CFR ≧2.0 was regarded as normal. Additionally, Doppler tissue imaging pulse wave measurements were taken from the lateral and septal corners of the mitral annulus. CFR values were significantly lower in the study group than in the control group (2.03 ± 0.3 vs. 2.61 ± 0.5, p = 0.005). In 5 of 10 hemodialysis patients, CFR was <2.0 (50%), however in only 1 of 14 control patients it was <2.0 (5%). Conclusions: Impairment of coronary microvasculature occurs earlier in patients with chronic renal failure and may be the harbinger of subsequent primary uremic myocardial disease. In patients with chronic renal failure and normal coronary arteries, decreased CFR by transthoracic echocardiography might be regarded as an early finding of an affected coronary vasculature.

Impaired coronary microvascular function and increased intima-media thickness in rheumatoid arthritis

BACKGROUND Rheumatoid arthritis (RA) is associated with excessive cardiovascular mortality. Recently, some studies have shown endothelial dysfunction in RA patients with high inflammatory activity. In addition, it has been suggested that the chronic inflammatory state of RA contributes to accelerated atherosclerosis. Therefore, we aimed to evaluate whether coronary microvascular dysfunction and increased carotid artery intima-media thickness exist in patients with a long history and well controlled disease activity of RA lacking traditional cardiovascular risk factors. METHODS Thirty RA patients (22 women; mean age 43.7+/-9.0) and 52 healthy volunteers (38 women; mean age 45.3+/-5.4) were included into the study. Using transthoracic echocardiography, each subject underwent echocardiographic examination including coronary flow reserve (CFR) and carotid intima-media thickness (IMT) measurement. RESULTS CFR values were statistically reduced for RA patients as compared to controls (2.4+/-0.5 vs. 2.7+/-0.4, P=0.002) whereas IMT values were significantly increased (0.6+/-0.1 vs. 0.5+/-0.1, P=0.001). In RA patients, CFR positively correlated with lateral Em/Am ratio (r=0.399, P=0.029), and negatively correlated with lateral isovolumic relaxation time (IVRT) (r=-0.744, P=0.005), IMT (r=-0.542, P=0.002) and RA disease duration (r=-0.495, P=0.005). Reflecting LV diastolic function, mitral E-wave deceleration time and isovolumic relaxation time were borderline significant between the groups, however lateral Em/Am ratio and lateral IVRT were statistically different. CONCLUSIONS Patients with RA had impaired CFR and increased carotid IMT, and these injurious effects correlated significantly with disease duration.

Mean platelet volume is increased in patients with severe obstructive sleep apnea

Abstract Increased platelet activation and aggregation which are closely related to cardiovascular complications have been reported in patients with obstructive sleep apnea (OSA). The aim of this study was to assess the mean platelet volume (MPV), an indicator of platelet activation in patients with OSA. The 95 subjects referred for evaluation of OSA underwent overnight polysomnography. Blood samples were taken for MPV determination. According to the apnea-hypopnea index (AHI), subjects were divided into three groups; group 1: control subjects without OSA (AHI < 5, n = 24), group 2: patients with mild to moderate OSA (AHI: 5–30, n = 42), and group 3: severe OSA (AHI > 30, n = 29). Body mass index (BMI) of patients with severe OSA was significantly higher than control subjects (31.5 ± 4.0 vs. 28.2 ± 5.0; p = 0.02). The MPV was significantly higher in patients with severe OSA than in the control group (8.9 ± 1.0 vs. 8.2 ± 0.7 fl; p = 0.01). Correlation analysis within 71 patients with OSA indicated that MPV was correlated with AHI (p < 0.001, r = 0.44) and DI (p = 0.001, r = 0.37). In multivariate regression analysis, when MPV was taken as independent with other study variables which are potential confounders such as age, gender and BMI, MPV was independently correlated with both AHI (β = 0.44, p < 0.001) and DI (β = 0.38, p < 0.001). We have shown that MPV was significantly higher in patients with severe OSA when compared with control subjects and MPV was correlated with AHI and DI.

Mean platelet volume in patients with prehypertension and hypertension

Patients with hypertension have evidence of platelet activation. Mean platelet volume (MPV), an indicator of platelet activation has been shown to be elevated in patients with hypertension. Prehypertension is also associated with an increase in cardiovascular morbidity and mortality. The aim of this study was to assess the MPV in patients with prehypertension and hypertension. This study included newly diagnosed and untreated 87 prehypertensive patients, 30 hypertensive patients and 35 normotensive control subjects matched for age, gender, and body mass index. All patients and controls gave informed consent. The MPV values of patients with prehypertension and hypertension were significantly higher than those of the control group (8.4 +/- 0.8 and 8.8 +/- 0.7 versus 7.9 +/- 0.5 fl; p < 0.05 and p < 0.001 respectively). It was also higher in hypertensives than in prehypertensives (8.8 +/- 0.7 versus 8.4 +/- 0.8 fl; p < 0.05). However, we found that the presence of the hypertension (beta = 0.28, P = 0.003) was only significant predictors of higher MPV in a multivariable model that adjusted for other variables. We have shown that, MPV, an indicator of platelet activation was significantly higher in patients with prehypertension and hypertension when compared with control subjects. We have also showed that MPV was also higher in patients with hypertension than in patients with prehypertension. However, presence of the hypertension was only significant predictor of higher MPV.

Nebivolol Improves Coronary Flow Reserve in Patients with Idiopathic Dilated Cardiomyopathy

Background: Impaired coronary flow reserve (CFR) is a significant predictor of poor prognosis in patients with idiopathic dilated cardiomyopathy (IDC). Nebivolol reduces mortality and morbidity in patients with heart failure and left ventricular dysfunction, including cases caused by IDC. Objective: To assess the effects of nebivolol on CFR in patients with IDC. Methods: CFR was measured in 21 clinically stable patients with IDC (mean (SD) ejection fraction 35.7 (6.2)) at baseline and after 1 month of treatment with nebivolol once daily. A control group of apparently healthy subjects who were matched for age and sex was used for comparison. Resting and hyperaemic coronary flows were measured using transthoracic second-harmonic Doppler echocardiography. None of the subjects had any systemic disease. Results: After 1 month of treatment, heart rate was reduced significantly (p<0.001). The blood pressure was decreased significantly (p<0.001). The left ventricular end-diastolic diameter and stroke volume were not changed significantly, but end-systolic diameter was decreased significantly (p<0.05). Resting rate–pressure product was lower after treatment with nebivolol, but dipyridamole-induced change was not influenced by the treatment. Nebivolol treatment reduced significantly coronary velocities at rest (p<0.02) and also caused a significant increase in coronary velocities after dipyridamole (p<0.02), leading to a greater CFR (2.02 (0.35) vs 2.61 (0.43), p<0.001). Nebivolol induced an absolute increase of 6% in the CFR in 17 of 21 patients (80.9%). Conclusions: In patients with IDC, 1 month of treatment with nebivolol induces a marked increase in CFR.

Effect of Smoking Cessation on Mean Platelet Volume

The aim of this study was to assess the values of mean platelet volume (MPV) in regular smokers and the effect of smoking cessation on MPV. The study group consisted of 116 regular smokers (57 females and 59 males; mean age 46.3 ± 12.7 years) and the control group was composed of 90 healthy volunteers (49 females and 41 males; mean age 47.7 ± 8.3 years). Platelet indices were assessed in regular smokers and control participants. Platelet indices were measured at 3 months after smoking cessation in these 101 participants. The MPV values were significantly higher in smokers than those of controls (8.8 ± 0.9 vs 8.0±0.8 fL, respectively; P < .001). The MPV values decreased significantly at 3 months when compared with the baseline values (8.9 ± 1.0 vs 7.9 ± 0.7 fL, respectively; P < .001). We have found that serum MPV values were significantly higher in regular smokers than in controls. Serum MPV values decreased significantly at 3 months after smoking cessation.