Snapshots of Hemodynamics (eBook)

Snapshots of Hemodynamics 3
Preface 5
Acknowledgement 7
Contents 9
How to useSnapshots of Hemodynamics 13
Description 13
Physiological and Clinical Relevance 13
References 13
Part A:Basics of Hemodynamics 15
Chapter 1: Viscosity 16
Description 16
Viscosity of Blood 17
Anomalous Viscosity or Non-Newtonian Behavior of Blood 18
How to Measure Viscosity 20
Physiological and Clinical Relevance 20
References 21
Chapter 2: Law of Poiseuille 22
Description 22
Calculation of Wall Shear Stress 24
Example of the Use of Poiseuille’s Law to Obtain Viscosity 25
Murray’s Law 25
Physiological and Clinical Relevance 27
References 27
Chapter 3: Bernoulli’s Equation 28
Description 28
Physiological and Clinical Relevance 29
Applying Bernoulli’s Law 29
Calculation of Aortic Valvular Area 30
Jets and Vena Contracta 31
Kinetic Energy 31
The Hydrostatic Pressure 31
References 33
Chapter 4: Turbulence 34
Description 34
Physiological and Clinical Relevance 35
References 36
Chapter 5: Arterial Stenosis 37
Description 37
Post-Stenotic Dilatation 38
Physiological and Clinical Relevance 39
Flow Reserve 40
Fractional Flow Reserve 40
References 42
Chapter 6: Resistance 43
Description 43
Addition of Resistances 44
Physical Reason Why the Resistance Is Located in the Arterioles 45
Resistance of Capillaries and Veins 45
Calculation of Vascular Resistance 46
Physiological and Clinical Relevance 46
Low Resistance of an Arterio-Venous Fistula 47
References 48
Chapter 7: Inertance 49
Description 49
Addition of Series and Parallel Inertances 50
Physiological and Clinical Relevance 50
References 52
Chapter 8: Oscillatory Flow Theory 53
Description 53
Physiological and Clinical Relevance 54
Reference 55
Chapter 9: Law of Laplace 56
Description 56
Applicability of the Law of Laplace 57
Relation to the Young Modulus 58
Physiological and Clinical Relevance 58
References 59
Chapter 10: Elasticity 60
Description 60
Viscoelasticity 62
Viscoelastic Models 63
Residual Stresses and Stress Distribution at Physiological Loads 63
Physiological and Clinical Relevance 65
The Elasticity of Cardiovascular Tissue 66
Determination of the Young Modulus 66
References 67
Chapter 11: Compliance 68
Description 69
Measurement of Elastance and Compliance 69
Distensibility and Bulk Modulus 70
The Pressure-Strain Elastic Modulus 71
The Stiffness Index 71
Describing the Pressure-Area or Pressure-Diameter Relation of Blood Vessels 71
Addition of Compliances and Elastances 72
Relating Compliance to Young Modulus 73
Physiological and Clinical Relevance 74
Buffering Function of Compliance 75
References 76
Part BCardiac Hemodynamics 78
Chapter 12: Cardiac Muscle Mechanics 79
Description 79
Calcium 80
The Force-Length Relation 81
The Force-Velocity Relation 82
The F-v Relation and Pump Function 83
Experimental Problems 84
Nomenclature Problems 84
Limitations of the Sliding Filament Model 85
Physiological and Clinical Relevance 85
References 86
Chapter 13: The Pressure-Volume Relation 87
Description 88
The Varying Elastance Model 88
Determination of Emax 89
Physiological and Clinical Relevance 91
The Frank-Starling Law 91
Systolic and Diastolic Dysfunction 91
Concentric and Eccentric Hypertrophy 93
Modeling on the Basis of the Varying Elastance Concept 94
Limitations 94
References 95
Chapter 14: The Pump Function Graph 96
Description 97
Relation Between the Pump Function Graph and the End-Systolic Pressure-Volume Relation 99
Physiological and Clinical Relevance 100
The Frank-Starling Law 100
Concentric Hypertrophy and Heart Failure 101
Exercise 103
Limitations 103
References 104
Chapter 15: Cardiac Work, Energy and Power 105
Description 105
Physiological and Clinical Relevance 106
Calculations 107
References 107
Chapter 16: Cardiac Oxygen Consumption and Hemodynamics 108
Description 109
Rate Pressure Product and Tension Time Index 109
The Pressure Volume Area 110
Heterogeneity of Metabolism 111
Physiological and Clinical Relevance 112
Limitations 112
References 113
Chapter 17: Cardiac Power and Ventriculo-Arterial Coupling 114
Description 115
Power and Efficiency 115
Maximum Cardiac Efficiency and Maximum Power in the Intact Animal 115
Local Work and Power 115
Heat Production and Transport 116
Assessment of Ventriculo-Arterial Coupling 116
Theory of Optimal Heart Size 118
Physiological and Clinical Relevance 119
Related Issues 120
References 120
Chapter 18: The Coronary Circulation 122
Description 123
Autoregulation of Coronary Flow 123
Autoregulation Gain 125
Reactive Hyperemia and Maximal Vasodilation 125
Instantaneous Pressure-Flow Relations 125
Cardiac Contraction and Coronary Flow 126
Microvascular Aspects 130
Physiological and Clinical Relevance 131
Coronary Flow in Layers 131
Supply-Demand 132
Coronary Stenosis 133
References 133
Chapter 19: Assessing Ventricular Function 135
Description 136
Global Left Ventricular Contractile Function Compared Between Patients 137
Invasive Assessment of Global Ventricular Function in the Patient 137
Merits and Drawbacks of dPLV/dtmax, ESPVR and Emax as Assessments of Global Contractility 138
Noninvasive Assessment of Global Ventricular Function in the Patient 140
Assessment of Change in Regional Left Ventricular Function 140
Physiological and Clinical Relevance 140
References 141
Part CArterial Hemodynamics 142
Chapter 20: Wave Travel and Velocity 143
Description 144
Wave Speed Depends on Vessel Compliance 144
Phase Velocity and Apparent Phase Velocity 145
Methods to Obtain Wave Speed 146
Physiological and Clinical Relevance 148
Time Delay or Foot-to-Foot Method 148
Wave Speed Depends on Pressure 148
Wave Speed Depends on Age 149
References 150
Chapter 21: Wave Travel and Reflection 151
Description 152
Physiological and Clinical Relevance 153
References 156
Chapter 22: Waveform Analysis 158
Description 159
Wave Separation Analysis: Forward and Backward Running Components 159
Physiological and Clinical Relevance 161
Practical Determination of Characteristic Impedance 162
Reflections Depend on the Vascular Bed and on Its Vasoactive State 162
References 163
Chapter 23: Arterial Input Impedance 164
Description 165
Definition of Impedance 165
Derivation of Input Impedance 165
Limitations 166
Hemodynamic Elements 167
Explanation of Input Impedance 167
Effective Length of the Arterial System 168
External Power 169
Impulse Response 169
Physiological and Clinical Relevance 170
The Characteristic Pressure Wave Shapes in Old and Young Subjects 171
Changes in Reflection 172
Hypertension 173
References 174
Chapter 24: The Arterial Windkessel 175
Description 175
How the Arterial Tree Reduces to a Windkessel 178
Other Lumped Models 179
Physiological and Clinical Relevance 179
References 183
Chapter 25: Distributed Models and Tube Models 184
Description 185
Single Tube and Two-Tube Models 187
Physiological and Clinical Relevance 187
References 187
Chapter 26: Transfer of Pressure 189
Description 190
Definition of Transfer function 190
Calibration of Noninvasively Determined Pressure Wave Shapes 191
Physical Basis and Simple Mathematical Model for Transfer Function 191
Physiological and Clinical Relevance 193
References 194
Chapter 27: Mechanotransduction and Vascular Remodeling 196
Description 196
Short Term Arterial Adaptation 197
Mechanotransduction 197
Long Term Vascular Adaptation 198
Residual Stress in Relation to Growth and Remodeling 200
Physiological and Clinical Relevance 201
Arterial Remodeling in Hypertension 201
Arterial Remodeling in Hypertension: Large Arteries 201
Flow Mediated Dilatation, as a Means to Evaluate Endothelial Function 202
Low Shear and Atheroma 203
References 204
Chapter 28: Blood Flow and Arterial Disease 205
Description 206
Shear Stress and Endothelial Function 206
Physiological and Clinical Relevance 207
Assessing Risk for Atherosclerosis 207
Shear Stress and Intima Hyperplasia in Vein Grafts 207
Shear Stress and Intima Hyperplasia in Bypass Grafts 207
Intima Hyperplasia Following Angioplasty and Stenting 208
References 209
Part DIntegration 210
Chapter 29: Determinants of Pressure and Flow 211
Description 212
Dimensional Analysis 212
Physiological and Clinical Relevance 214
Contribution of Arterial System and Heart in Systolic Hypertension 215
References 217
Chapter 30: Comparative Physiology 218
Description 219
Basal Whole Body and Cardiac Metabolism 223
Cardiac Metabolism 223
Pulse Wave Velocity and Reflections 223
Physiological and Clinical Relevance 224
References 224
Part EAppendices 226
Appendix 1: Times and Sines: Fourier Analysis 227
Description 228
Limitations 229
Physiological and Clinical Relevance 230
References 231
Appendix 2: Basic Hemodynamic Elements 232
Description 233
Physiological and Clinical Relevance 233
Limitations 233
Reference 233
Appendix 3: Vessel Segment 234
Description 234
The Longitudinal Impedance 235
The Transverse Impedance 235
Large and Small Arteries 236
Physiological and Clinical Relevance 236
References 236
Appendix 4: Wave Speed and Characteristic Impedance 237
Description 238
Calculation of Characteristic Impedance 239
Calculation of Reflection Coefficient 239
Physiological and Clinical Relevance 240
References 240
Appendix 5: Basic Aspects 241
Description 241
Pressure and Flow 241
Pulsatile and Oscillatory Pressure and Flow 242
Area 242
Wave Speed Differs from Flow Velocity 242
Volume, Flow, and Circulation Time 243
The Navier-Stokes Equations 244
Reference 244
Appendix 6: Books for Reference 245
Appendix 7: Symbols 247
Appendix 8: Units and Conversion Factors 250
Index 252