Microcirculatory Dysfunction in Cardiac Syndrome X: Role of Abnormal Blood Rheology

Lee, Byoung Kwon; Durairaj, Azhil; Mehra, Anilkumar; Wenby, R.B.; Meiselman, Herbert J.; Alexy, Tamás

doi:10.1080/10739680701797090

Cited by 32 publications

(21 citation statements)

References 52 publications

(59 reference statements)

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“…55 Furthermore, patients with cardiac syndrome X have markedly elevated red blood cell aggregation and whole-blood viscosity, which might contribute to the pathophysiology of the disease. 52 these data suggest that therapeutic approaches that aim to normalize blood rheology warrant investigation. in this context, it is noteworthy that fibrate treatment decreases the viscosity of the plasma and blood and the aggregation of red blood cells in patients with dys lipidemia with or without type 2 diabetes mellitus.…”

Section: Coronary Microangiographymentioning

confidence: 92%

“…mechanisms that might underlie this syndrome include endothelial dysfunction, abnormal vaso constrictive responses of the micro vasculature to nitric oxide and endothelin, and hemorheologic abnormalities. 52 Preliminary studies suggest that lipid-modifying therapies might have some benefits. treatment with pravastatin (40 mg daily) in predominantly middle-aged women with slightly elevated levels of lDl cholesterol and triglycerides (mean values 3.12 ± 0.64 mmol/l and 3.43 ± 1.29 mmol/l) was associated with improvements in flow-mediated vasodilatation, exercise duration, time to ischemic electrocardiographic st segment changes (defined as 1 mm st segment depression) and endothelial function.…”

Section: Coronary Microangiographymentioning

confidence: 99%

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Residual microvascular risk in diabetes: unmet needs and future directions

et al. 2009

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The burden of microvascular disease in patients with type 2 diabetes mellitus continues to escalate worldwide. Current standards of care reduce but do not eliminate the risk of diabetic retinopathy, nephropathy or neuropathy in these patients. Correction of atherogenic dyslipidemia, which is characterized by elevated triglyceride levels and low levels of HDL cholesterol, might provide additional benefit. Whereas promising data have been published with respect to fibrate therapy for maculopathy, fenofibrate for diabetic retinopathy, and statin or fibrate therapy for diabetic nephropathy, further studies are warranted to define optimal management strategies for reducing the residual microvascular risk. Such strategies are especially relevant in cases of diabetic peripheral neuropathy, where even optimal care fails to affect disease progression. Identification of those factors that are most relevant to residual diabetes-related microvascular risk is a priority of an ongoing multinational epidemiological study. In this Review, we highlight an urgent need to address the issue of microvascular residual risk in patients with or at risk of type 2 diabetes mellitus.

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Section: Coronary Microangiographymentioning

confidence: 92%

Section: Coronary Microangiographymentioning

confidence: 99%

Residual microvascular risk in diabetes: unmet needs and future directions

et al. 2009

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“…An optical aggregometer (Myrenne aggregometer MA1, Roentgen, Germany) was used to quantify the RBC aggregation in terms of the aggregation index (M). The aggregation tendency of the blood samples was adjusted to physiological (M = 12-16) and pathological (M > 20) levels seen in humans by adding Dextran 500 (average molecular mass of 460 kDa, Sigma) at concentration of 5.0 and 7.5 mg/ml, respectively (Baskurt et al, 1997b; Kim et al, 2006a; Lee et al, 2008). …”

Section: Methodsmentioning

confidence: 99%

Two-phase model for prediction of cell-free layer width in blood flow

Namgung

Cabrales

et al. 2013

Microvascular Research

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This study aimed to develop a numerical model capable of predicting changes in the cell-free layer (CFL) width in narrow tubes with consideration of red blood cell aggregation effects. The model development integrates to empirical relations for relative viscosity (ratio of apparent viscosity to medium viscosity) and core viscosity measured on independent blood samples to create a continuum model that includes these two regions. The constitutive relations were derived from in vitro experiments performed with three different glass-capillary tubes (inner diameter = 30, 50 and 100 μm) over a wide range of pseudoshear rates (5-300 s−1). The aggregation tendency of the blood samples was also varied by adding Dextran 500 kDa. Our model predicted that the CFL width was strongly modulated by the relative viscosity function. Aggregation increased the width of CFL, and this effect became more pronounced at low shear rates. The CFL widths predicted in the present study at high shear conditions were in agreement with those reported in previous studies. However, unlike previous multi-particle models, our model did not require a high computing cost, and it was capable of reproducing results for a thicker CFL width at low shear conditions, depending on aggregating tendency of the blood.

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“…This is the viscosity of blood measured at a low shear rate of 5 s -1 or less. In patients presenting with essential hypertension,20) myocardial infarction,20)21) ischemic stroke,22)23) or PAD,24) the DBV levels have been observed to be higher than that of healthy controls. The DBV in normal human subjects is about 20 cP (200 mP) at a shear rate of 1 s -1 (Fig.…”

Section: Hemorheologymentioning

confidence: 98%

Hemorheology and Microvascular Disorders

Cho

Cho²

2011

Korean Circ J

101

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The present review presents basic concepts of blood rheology related to vascular diseases. Blood flow in large arteries is dominated by inertial forces exhibited at high flow velocities, while viscous forces (i.e., blood rheology) play an almost negligible role. When high flow velocity is compromised by sudden deceleration as at a bifurcation, endothelial cell dysfunction can occur along the outer wall of the bifurcation, initiating inflammatory gene expression and, through mechanotransduction, the cascade of events associated with atherosclerosis. In sharp contrast, the flow of blood in microvessels is dominated by viscous shear forces since the inertial forces are negligible due to low flow velocities. Shear stress is a critical parameter in microvascular flow, and a force-balance approach is proposed for determining microvascular shear stress, accounting for the low Reynolds numbers and the dominance of viscous forces over inertial forces. Accordingly, when the attractive forces between erythrocytes (represented by the yield stress of blood) are greater than the shear force produced by microvascular flow, tissue perfusion itself cannot be sustained, leading to capillary loss. The yield stress parameter is presented as a diagnostic candidate for future clinical research, specifically, as a fluid dynamic biomarker for microvascular disorders. The relation between the yield stress and diastolic blood viscosity (DBV) is described using the Casson model for viscosity, from which one may be able determine thresholds of DBV where the risk of microvascular disorders is high.

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Microcirculatory Dysfunction in Cardiac Syndrome X: Role of Abnormal Blood Rheology

Cited by 32 publications

References 52 publications

Residual microvascular risk in diabetes: unmet needs and future directions

Residual microvascular risk in diabetes: unmet needs and future directions

Two-phase model for prediction of cell-free layer width in blood flow

Hemorheology and Microvascular Disorders

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