Outcomes and effectiveness of bilateral percutaneous transluminal renal artery stenting in patients with critical bilateral renal artery stenosis

Background: The aim of this study was to assess the effects of percutaneous bilateral renal artery stenting in patients with atherosclerotic renal artery stenosis and in-hospital and 4 month outcome of the procedure, focusing on the changes in renal function and blood pressure. Methods: Five consecutive patients (mean age: 64.8 ± 9.7 years, 1 women) with bilateral renal artery stenoses underwent percutaneous interventions. We compared blood pressure, number of oral antihypertensive medications, and renal function changes preprocedure and postprocedure at 4 months follow-up. Results: A total of 5 bilateral atherosclerotic renal artery stenosis patients underwent percutaneous transluminal renal angioplasty and 10 stents were placed. Although systolic and diastolic blood pressures were significantly decreased in follow-up period, glomerular filtration rates were not significantly changed as compared with baseline data (p = 0.009, p = 0.008, p = 1.00, respectively). Also, the number of oral antihypertensive medications were significantly decreased at follow-up period (p = 0.03). Conclusions: Bilateral renal artery stenting provides a beneficial outcome such as stabilization of renal functions, significant improvement in blood pressure control and reduction in the number of oral antihypertensive medications at follow-up

Acute effects of cardiac resynchronization therapy on arterial distensibility and serum norepinephrine levels in advanced heart failure

Background: Cardiac resynchronization therapy (CRT) has become an accepted method fortreating refractory heart failure (HF). Arterial distensibility is an index of arterial stiffnessand a surrogate marker for atherosclerosis. The present study aims to assess the acute effects of ventricular resynchronization therapy with biventricular stimulation on arterial distensibility, echocardiographic parameters and serum norepinephrine levels in patients with drugrefractory HF.Methods: Fourteen cardiac HF patients (53.6 ± 9.1; 39–67 years, 7 woman) were enrolled for CRT. Patients had an advanced cardiac HF (NYHA III–IV functional class) due to non-ischemic dilated cardiomyopathy, with a left ventricular ejection fraction (LVEF) < 35% and QRS duration ≥ 120 ms. Blood samples for norepinephrine and B-type natriuretic peptidewere collected before 24 h biventricular implantation and after 48 h of CRT. Transthoracic echocardiography was used to evaluate arterial distensibility and cardiovascular condition.Results: Although systolic blood pressure, diastolic blood pressure, LV end-diastolic diameter, LV end-systolic diameter, serum B-type natriuretic peptide, and serum norepinephrine levels significantly decreased after CRT implantation; EF and aortic distensibility significantly increased (p < 0.05). There was no significance in the hemodynamic and echocardiographic values, norepinephrine and B-type natriuretic peptide levels in pre- and post-CRT between man and woman.Conclusions: The major findings of this study are that in patients with cardiac HF in acute period, after implantation of CRT serum norepinephrine levels decrease and the arterial distensibility improves

Acute effects of oral melatonin administration on arterial distensibility, as determined by carotid-femoral pulse wave velocity, in healthy young men

The aim of the present study was to investigate the effects of melatonin administration on arterial distensibility by using carotid-femoral (aortic) pulse wave velocity (PWV) measurements in healthy young men. Ten men were studied (five men in the melatonin group and five men in the placebo group) by physicians. Carotid-femoral (aortic) PWV, blood pressure and plasma melatonin were measured in the supine position before and 60 min after oral administration of melatonin or placebo. Although carotid-femoral (aortic) PWV, systolic blood pressure and mean blood pressure were decreased, pulse wave propagation time and plasma melatonin levels were increased at 60 min after oral melatonin (1 mg) administration (P=0.04, P=0.04, P=0.04, P=0.04 and P=0.04, respectively). No significant differences were found between all parameters in the placebo group (P>0.05). In conclusion, these findings indicate that melatonin administration, compared with placebo, decreased carotid-femoral PWV and systolic blood pressure in the supine position in healthy young men. Administration of melatonin may have an inhibitory effect on sympathetic tone. © 2006 Pulsus Group Inc. All rights reserved

Designing a Distributed Multi-agent System for Compiler Optimization

This paper explores the run time performance improvements using different GCC optimization flags in program compilation. As multi-core microprocessor systems replacing legacy single-core ones, tremendous effort is needed to address to optimize the associated compilers for newly designed architectures in order to suit them for running parallel programming on multiple cores. Therefore, the aim of this paper is to address this challenge by designing an optimum distributed multi-agent system to perform compiler optimization. A multi-agent framework is adopted to utilize random and genetic algorithm-based search algorithm to find the best GCC optimization flags for a given program. The framework is highly scalable and can be extended with distributed system concept to perform code compilation in parallel to find the best-optimized code sequence in a short amount of time. The initial performance results have promising indicators which clearly show that the performance improvement is achieved

An Expanding Role of Biomarkers in Pulmonary Arterial Hypertension

Background: Pulmonary Arterial Hypertension (PAH) is a chronic disease which may cause or result from multiple cardiopulmonary disorders. The disease has complex pathophysiological mechanisms and involves many systematic, cellular and molecular changes. Therefore, it is crucial to find out underlying mechanisms and detect biomarkers to achieve early and proper diagnosis, evaluating disease severity, for follow-up and monitor response to treatment. Many biomarkers for PAH have been investigated but yet no such biomarker has been found specific and easily accessible to use for the patients. This review aims to identify an expanding role of biomarkers in PAH

Simulation of Eisenmenger syndrome with ventricular septal defect using equivalent electronic system

Background: In this study, we aim to investigate the simulation of the cardiovascular system using an electronic circuit model under normal and pathological conditions, especially the Eisenmenger syndrome. Methods and Results: The Eisenmenger syndrome includes a congenital communication between the systemic and pulmonary circulation, with resultant pulmonary arterial hypertension and right-to-left reversal of flow through the defect. When pulmonary vascular resistance exceeds systemic vascular resistance, it results in hypoxaemia and cyanosis. The Westkessel model including Resistor-Inductance-Capacitance pi-segments was chosen in order to simulate both systemic and pulmonary circulation. The left and right heart are represented by trapezoidal shape stiffness for better simulation results. The Eisenmenger syndrome is simulated using a resistance (septal resistance) connected between the left ventricle and right ventricle points of the model. Matlab (R) is used for the model implementation. In this model, although there is a remarkable increase in the pulmonary artery pressure and right ventricle pressure, left ventricle pressure, aortic pressure, aortic flow, and pulmonary compliance decrease in the Eisenmenger syndrome. In addition, left-to-right septal flow reversed in these diseases. Conclusion: Our model is effective and available for simulating normal cardiac conditions and cardiovascular diseases, especially the Eisenmenger syndrome