A polymer-based, paclitaxel-eluting stent in patients with coronary artery disease☆

OBJECTIVES
This study assessed the clinical utility of mitral annulus velocity in the evaluation of left ventricular diastolic function.


BACKGROUND
Mitral inflow velocity recorded by Doppler echocardiography has been widely used to evaluate left ventricular diastolic function but is affected by other factors. The mitral annulus velocity profile during diastole may provide additional information about left ventricular diastolic function.


METHODS
Mitral annulus velocity during diastole was measured by Doppler tissue imaging (DTI) 1) in 59 normal volunteers (group 1); 2) in 20 patients with a relaxation abnormality as assessed by Doppler mitral inflow variables (group 2) at baseline and after saline loading; 3) in 11 patients (group 3) with normal diastolic function before and after intravenous nitroglycerin infusion; and 4) in 38 consecutive patients (group 4) undergoing cardiac catheterization in whom mitral inflow velocity and tau as well as mitral annulus velocity were measured simultaneously.


RESULTS
In group 1, mean +/- SD peak early and late diastolic mitral annulus velocity was 10.0 +/- 1.3 and 9.5 +/- 1.5 cm/s, respectively. In group 2, mitral inflow velocity profile changed toward the pseudonormalization pattern with saline loading (deceleration time 311 +/- 84 ms before to 216 +/- 40 ms after intervention, p < 0.001), whereas peak early diastolic mitral annulus velocity did not change significantly (5.3 +/- 1.2 cm/s to 5.7 +/- 1.4 cm/s, p = NS). In group 3, despite a significant change in mitral inflow velocity profile after nitroglycerin, peak early diastolic mitral annulus velocity did not change significantly (9.5 +/- 2.2 cm/s to 9.2 +/- 1.7 cm/s, p = NS). In group 4, peak early diastolic mitral annulus velocity (r = -0.56, p < 0.01) and the early/late ratio (r = -0.46, p < 0.01) correlated with tau. When the combination of normal mitral inflow variables with prolonged tau (> or = 50 ms) was classified as pseudonormalization, peak early diastolic mitral annulus velocity < 8.5 cm/s and the early/late ratio < 1 could identify the pseudonormalization with a sensitivity of 88% and specificity of 67%.


CONCLUSIONS
Mitral annulus velocity determined by DTI is a relatively preload-independent variable in evaluating diastolic function.

Assessment of Mitral Annulus Velocity by Doppler Tissue lmaging in the Evaluation of Left Ventricular Diastolic Function

Principles of exercise testing and interpretation

The interest in the left atrium (LA) has resurged over the recent years. In the early 1980s, multiple studies were conducted to determine the normal values of LA size. Over the past decade, LA size as an imaging biomarker has been consistently shown to be a powerful predictor of outcomes, including major public health problems such as atrial fibrillation, heart failure, stroke, and death. More recently, functional assessment of the LA has been shown to be, at least as, if not more robust, a marker of cardiovascular outcomes. Current available data suggest that the combined evaluation of LA size and LA function will augment prognostication. The aim of this review is to provide a critical appraisal of current echocardiographic techniques for the assessment of LA function and the implications of such assessment for prediction and disease prevention.

Left atrial function: physiology, assessment, and clinical implications

Introduction: Metabolic syndrome represents a cluster of related metabolic abnormalities, including central obesity, hypertension, dyslipidemia, hyperglycemia, and insulin resistance, with central obesity and insulin resistance in particular recognized as causative factors. These metabolic derangements present significant risk factors for cardiovascular disease, which is commonly recognized as the primary clinical outcome, although other outcomes are possible. Metabolic syndrome is a progressive condition that encompasses a wide array of disorders with specific metabolic abnormalities presenting at different times. These abnormalities can be detected and monitored via serum biomarkers. This review will compile a list of promising biomarkers that are associated with metabolic syndrome and this panel can aid in early detection and management of metabolic syndrome in high risk populations, such as in West Virginia.

Methods: A literature review was conducted using PubMed, Science Direct, and Google Scholar to search for markers related to metabolic syndrome. Biomarkers searched included adipokines (leptin, adiponectin), neuropeptides (ghrelin), pro-inflammatory cytokines (IL-6, TNF-α), anti-inflammatory cytokines (IL-10), markers of antioxidant status (OxLDL, PON-1, uric acid), and prothrombic factors (PAI-1).

Results: According to the literature, the concentrations of pro-inflammatory cytokines (IL-6, TNF-α), markers of pro-oxidant status (OxLDL, uric acid), and prothrombic factors (PAI-1) were elevated in metabolic syndrome. Additionally, leptin concentrations were found to be elevated in metabolic syndrome as well, likely due to leptin resistance. In contrast, concentrations of anti-inflammatory cytokines (IL-10), ghrelin, adiponectin, and antioxidant factors (PON-1) were decreased in metabolic syndrome, and these decreases also correlated with specific disorders within the cluster.

Conclusion: Based on the evidence presented within the literature, the aforementioned biomarkers correlate significantly with metabolic syndrome and could provide a minimally-invasive means for early detection and specific treatment of these disorders. Further research is encouraged to determine the efficacy of applying these biomarkers to diagnosis and treatment in a clinical setting.

/pdf/systematic-review-of-metabolic-syndrome-biomarkers-a-panel-1dld1v46dq.pdf

Systematic Review of Metabolic Syndrome Biomarkers: A Panel for Early Detection, Management, and Risk Stratification in the West Virginian Population.

BACKGROUND: Physical activity influences energy metabolism in human subjects by increasing activity-induced energy expenditure and resting metabolic rate for several hours after exercise. Effects of exercise on circulating thyroid hormone values remain controversial. We have investigated the effect of acute aerobic exercise on thyroid hormone values. MATERIALS/METHODS: The effect of different intensity levels of acute aerobic exercise on thyroid hormones was investigated in 60 male well-trained athletes by performing bicycle ergometer at 45% (low intensity), 70% (moderate intensity), and 90% (high intensity). These intensities were selected according to their maximum heart rate (MHR). At each intensity level, heart rate, blood lactic acid, serum total thyroxine (T4), free thyroxine (fT4), total triiodothyronine (T3), free triiodothyronine (fT3) and thyroid stimulating hormone (TSH) values were measured. RESULTS: The results of this study show that exercise performed at the anaerobic threshold (70% of maximum heart rate, lactate level 4.59 ± 1.75 mmol/l) caused the most prominent changes in the amount of any hormone values. While the rate of T4, fT4, and TSH continued to rise at 90% of maximum heart rate, the rate of T3 and fT3 started to fall. CONCLUSIONS: Maximal aerobic exercise greatly affects the level of circulating thyroid hormones.

Exercise intensity and its effects on thyroid hormones

In this study, we investigated the contribution of vitamin K epoxide reductase (VKORC1) and cytochrome P450 2C9 (CYP2C9) genotypes, age, and body surface area (BSA) on warfarin dose requirements and in an adult Turkish population. Blood samples were collected from 100 Turkish patients with stable warfarin dose requirements and an international normalized ratio (INR) of the prothrombin time within the therapeutic range. Genetic analyses for CYP2C9 genotypes (*2 and *3 alleles) and VKORC1 −1639 G>A polymorphism were performed and venous INR determined. The mean warfarin daily dose requirement was higher in CYP2C9 homozygous wild-type patients, compared to those with the variant *3 allele (P 0.05) and highest in patients with the VKORC1 −1639 GG genotype compared to those with the GA genotype and the AA genotype (P < 0.01). The time to therapeutic INR was longer in CYP2C9 homozygous wild-type patients compared with those with the variant *2 and *3 alleles (P < 0.01), and longer in patients with the VKORC1 (position −1639) GG genotype compared with those with the GA genotype and the AA genotype (P < 0.01). The multivariate regression model including the variables of age (R2 = 4.4%), BSA (R2 = 27.4%), CYP2C9 (R2 = 8.1%), and VKORC1 genotype (R2 = 34.1%) produced the best model for estimating warfarin dose (R2 = 60.4%). VKORC1 genotype and CYP2C9 polymorphism affect daily dose requirements and time to therapeutic INR in Turkish patients receiving warfarin for anticoagulation.

The impact of CYP2C9 and VKORC1 genetic polymorphism and patient characteristics upon warfarin dose requirements in an adult Turkish population.

Left ventricular (LV) systolic and diastolic parameters derived from Doppler echocardiography have been used widely to predict functional capacity but diastolic filling is affected by various factors. Tissue Doppler imaging (TDI) that records systolic and diastolic velocities within the myocardium and at the corners of the mitral annulus, has been shown to provide additional information about regional and global LV function. The goal of this study was to examine whether TDI-derived parameters add incremental value to other standard Doppler echocardiographic measurements in predicting exercise capacity. The study enrolled 59 consecutive patients with stable congestive heart failure (CHF). The etiology of heart failure was coronary artery disease in 42 patients and dilated cardiomyopathy in 17. Twenty-three age-matched healthy subjects were recruited as controls. Conventional echocardiographs and TDI were obtained. Early (Ea) and late (Aa) diastolic and systolic (Sa) mitral annulus velocities, the Ea/Aa and E/Ea ratios, were measured by pulsed wave TDI placed at the septal side of the mitral annulus and results were compared with results of cardiopulmonary exercise testing. Systolic and early diastolic velocities of mitral annulus were decreased and the E/Ea ratio was increased in the restrictive group as compared to controls (P = 0.02, P = 0.03, P 7.5 (P 7.5 had reduced exercise capacity, as did the group with restrictive LV filling patterns (12.8 +/- 3.3 vs 12.9 +/- 4.0 ml/min per kg, P = 0.9). Similarly, there was no significant difference in the mean exercise capacity between the patients with a nonrestrictive pattern vs restrictive pattern with E/Ea ratio 7.5 was used, 21 out of 24 patients in the reduced exercise capacity group were identified with 16 false positives in the preserved exercise capacity group (P = 0.001). Mitral annular systolic and diastolic velocities of TDI were associated with cardiopulmonary exercise capacity in patients with LV systolic dysfunction. Index of the E/Ea ratio was found to be the most powerful predictor of peak oxygen uptake.

Tissue Doppler imaging adds incremental value in predicting exercise capacity in patients with congestive heart failure

Previous studies revealed that there were various mutations on endothelial nitric oxide synthase (eNOS) gene and these mutations might be a risk factor for coronary artery disease (CAD), myocardial infarction (MI), and hypertension (HT). In this study, we aimed to investigate the relationship between eNOS gene polymorphism (T-786 C) and coronary artery disease in the Turkish population. Two hundred and eleven unrelated individuals (152 male, 59 female, mean age 59 years, range 27-85) whose angiographic examinations were performed in our hospital were enrolled into the study; 159 of these had angiographically determined coronary artery lesions (>or=50% stenosis at least in one vessel). Fifty-two individuals were free of coronary artery disease on their coronary angiography. The Gensini scoring system was used to determine the severity of the CAD. The polymerase chain reaction (PCR) method was used for genotyping the individuals. To determine the independent risk factors for coronary artery disease, multivariate logistic regression analysis was used. The variant distribution of the T-786 C polymorphism was as follows. For all individuals: TT 94 (44.5%), TC 88 (41.7%), CC 29 (13.8%); in CAD patients: TT 63 (39.6%), TC 73 (45.9%), CC 23 (14.5%); and in normal individuals: TT 31 (59.6%), TC 15 (28.8%), CC 6 (11.5%). There was a statistically significant difference in the variant distribution between CAD and normal individuals (P<0.05). On the other hand, when we compared the frequency of the at-least-one-C-allele carriers (CC+TC, dominant model) and TT homozygous, those with at least one C allele were more prevalent in CAD patients. The results were as follows. In coronary artery disease patients: CC+TC 96 (60.4%), TT 63 (39.6%); in normals: TC+CC 21 (40.4%), TT 31 (59.6%) (P<0.01). When we compared the allele distribution (T vs C, additive model) between CAD patients and normal controls, the results were as follows: T 0.625 vs 0.740, C 0.375 vs 0.260; there was also a statistically significant association between CAD and C allele (P<0.05). When we compared the means of the Gensini scores between each genotype of the T-786 C mutation, there was a statistically significant difference. The results were TT (48.6+/-37.3, median 43.0), TC (55.4+/-41.2, median 41.0), CC (77+/-43.6, median 80.0) (P<0.05). Multivariate logistic regression analysis revealed that C-dominant (CC+TC) individuals had 2.9-fold more likelihood to suffer from CAD (odds ratio: 2.902; confidence interval: 1.272-6.622) (P<0.05). We conclude that the T-786 C polymorphism of eNOS gene might be a risk factor for coronary artery disease in the Turkish population.

The relationship between endothelial nitric oxide synthase gene polymorphism (T-786 C) and coronary artery disease in the Turkish population

The aim of this study was to investigate the effects of acute or habitual exercise on visual evoked potentials (VEP). The study group consisted of 9 female and 7 male volleyball players and the control group contained 9 female and 7 male students who were not involved in any sportive activity. The N75, P100, and N145 latency and amplitudes were measured before and after exercise. Intragroup comparison was made to evaluate the acute effects and intergroup comparison for the chronic effects of exercise. Significant differences were noted between athletes and the sedentary subjects in terms of pre-exercise left-N145 latencies and amplitudes and left -P100 amplitudes. Right-eye N145 latencies of inactive female subjects obtained before and after exercise were also statistically different. The results suggest that acute and habitual exercise affects the VEP responses independent from the body temperature and other physiological parameters. Small sized pre-exercise P100 amplitudes in the athletes can be attributed to the effect of rapid visual-activity-demanding sports on the central nervous system. Visual evoked potentials maybe used as neurophysiological criteria in defining the performance of an athlete.

Effects of exercise on visual evoked potentials

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