Regional Blood Flow – ABC CARDIOL

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Case Report

Evaluation of Coronary Flow Reserve by Myocardial Scintigraphy in Left Ventricular Hypertrophy

Renata Christian Martins Felix et al. Felipe Hermely Villela Pedras Odorico de Souza Lima Neto Leonardo Medeiros Vitório

Introduction

The microvascular integrity of the myocardial bed can be assessed by coronary flow reserve (CFR), which is a calculation of the ratio between the absolute coronary blood flow under vasodilator stress and under resting conditions. This measurement is capable of estimating vasomotor dysfunction, and it reflects the hemodynamic effect of focal, diffuse, or small-vessel coronary disease.

Currently, it is possible to measure CFR invasively using the techniques of thermodilution or intracoronary Doppler and through non-invasive methods, such as echocardiography, magnetic resonance imaging, computed tomography, or nuclear medicine.

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Original Article

Influence of the tilt angle of Percutaneous Aortic Prosthesis on Velocity and Shear Stress Fields

Bruno Alvares de Azevedo Gomes et al. Gabriel Cordeiro Camargo Jorge Roberto Lopes dos Santos Luis Fernando Alzuguir Azevedo … Ângela Ourivio Nieckele Aristarco Gonçalves Siqueira-Filho Glaucia Maria Moraes de Oliveira

Abstract

Background:

Due to the nature of the percutaneous prosthesis deployment process, a variation in its final position is expected. Prosthetic valve placement will define the spatial location of its effective orifice in relation to the aortic annulus. The blood flow pattern in the ascending aorta is related to the aortic remodeling process, and depends on the spatial location of the effective orifice. The hemodynamic effect of small variations in the angle of inclination of the effective orifice has not been studied in detail.

Objective:

To implement an in vitro simulation to characterize the hydrodynamic blood flow pattern associated with small variations in the effective orifice inclination.

Methods:

A three-dimensional aortic phantom was constructed, reproducing the anatomy of one patient submitted to percutaneous aortic valve implantation. Flow analysis was performed by use of the Particle Image Velocimetry technique. The flow pattern in the ascending aorta was characterized for six flow rate levels. In addition, six angles of inclination of the effective orifice were assessed.

Results:

The effective orifice at the -4° and -2° angles directed the main flow towards the anterior wall of the aortic model, inducing asymmetric and high shear stress in that region. However, the effective orifice at the +3° and +5° angles mimics the physiological pattern, centralizing the main flow and promoting a symmetric distribution of shear stress.

Conclusion:

The measurements performed suggest that small changes in the angle of inclination of the percutaneous prosthesis aid in the generation of a physiological hemodynamic pattern, and can contribute to reduce aortic remodeling.

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Artigo Original

Vascular endothelial function in patients with coronary slow flow and the effects of nebivolol

Yilmaz Gunes et al. Hasan Ali Gumrukcuoglu Serkan Akdag Hakki Simsek … Musa Sahin Mustafa Tuncer

BACKGROUND: Brachial endothelial function has been associated with coronary slow flow (CSF). Increasing blood flow to brachial artery provokes endothelium to release nitric oxide (NO) with subsequent vasodilatation. Besides its β1-blocker activity, nebivolol causes vasodilatation by increasing endothelial NO release. OBJECTIVE: To assess the effects of nebivolol on vascular endothelial function in patients with CSF. METHODS: Forty-six patients with CSF and 23 individuals with normal epicardial coronary arteries were examined with transthoracic echocardiography and brachial artery ultrasonography. The patients were reevaluated two months after treatment with aspirin or aspirin plus nebivolol. RESULTS: Patients with CSF had higher body mass index (26.5 ± 3.3 vs. 23.8 ± 2.8, p < 0.001), mitral inflow isovolumetric relaxation time (IVRT) (114.9 ± 18.0 vs. 95.0 ± 22.0 msec, p < 0.001) and lower left ventricular ejection fraction (LVEF) (63.5 ± 3.1% vs. 65.4 ± 2.2, p = 0.009), HDL-cholesterol (39.4 ± 8.5 vs. 45.8 ± 7.7 mg/dL, p = 0.003) and brachial flow-mediated dilatation (FMD) (6.1 ± 3.9% vs. 17.6 ± 4.5%, p < 0.001). There were significant correlations between FMD and the presence of CSF (r = 0.800, p < 0.001) and HDL-cholesterol (r = 0.349, p = 0.003). Among Patients with CSF, although pretreatment mean FMD values were similar (6.1 ± 4.3% vs. 6.0 ± ,6%, p = 0.917) compared to aspirin alone group, posttreatment FMD was significantly higher in patients treated with aspirin plus nebivolol (6.0 ± 3.5% vs. 8.0 ± 2.9%, p = 0.047). Treatment with nebivolol was associated with a significant increase in FMD (6.0 ± 3.6 to 8.0 ± 2.9 %, p = 0.030) whereas treatment with aspirin alone was not. CONCLUSION: Endothelial function may be impaired in both coronary and brachial arteries in patients with CSF and nebivolol may be effective in the improvement of endothelial function in patients with CSF.

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Evaluation of Coronary Flow Reserve by Myocardial Scintigraphy in Left Ventricular Hypertrophy

Introduction

Influence of the tilt angle of Percutaneous Aortic Prosthesis on Velocity and Shear Stress Fields

Abstract

Background:

Objective:

Methods:

Results:

Conclusion:

Vascular endothelial function in patients with coronary slow flow and the effects of nebivolol

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Electronic Document Format (ABNT)

Electronic Document Format (APA)

Electronic Document Format (ISO)

Electronic Document Format (Vancouver)

Electronic Document Format (ABNT)

Electronic Document Format (APA)

Electronic Document Format (ISO)