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McDonald’s Blood Flow in
Arteries: Theoretical, Experimental and Clinical Principles. Fifth
Edition.
Wilmer W. Nicholas and Michael F. O’Rourke
New York, NY: Oxford Univ. Press, 2005, 607 pp., illus., index, $225.00.
ISBN: 0340809418
It is always a delight to read this standard work on the complicated
relation between blood flow and pressure in arteries. Over the years it
has evolved from a monograph for relative insiders to a textbook for a
much broader readership, including biologists, (patho) physiologists and
medical doctors. Considering the broader readership, it is of utmost
importance that the complexity of the phenomena is described in a logical
order. This has been further improved in the present edition. Also,
improvements have been made regarding the understanding of the complicated
theoretical aspects by reading only the text and skipping the equations,
what medical doctors generally do, e.g., by adding new clarifying figures.
New Chapters on “Endothelial function” (Chapter 5), “Cardiac Failure:
clinical implications” (Chapter 15), “Generalized and metabolic disease”
(Chapter 23) and “Pressure pulse waveform analysis” (Chapter 26) have been
added, the latter two containing information presented in other or
separate chapters in the previous edition. This reorganization is an
improvement. The addition of the chapters 5 and 15 is timely from a
medical point of view. The new chapter (20) on “Interpretation of blood
pressure in epidemiological studies and clinical trials” is an asset.
These types of studies, which are rapidly increasing in number, provide
important information about the arterial system, for example, in aging and
in diseases as hypertension. In these studies, however, the parameters to
describe arterial function are often derived in an indirect way,
necessitating critical analysis of the methods employed and the data
obtained. In general the approaches taken in these studies are analyzed
critically. However, in the discussion of the applicability of generalized
transfer functions to reconstruct the aortic pressure waveform from
peripheral pressure waveforms, the authors are less critical. For example,
the substantial, individual spread in transfer function modulus, limiting
inter-subject comparisons, and the relative contribution of higher
harmonics to details of the aortic pressure waveform should have been
emphasized. The chapter on “Exercise” (Chapter 25) is partly rewritten;
new and relevant information has been added. It makes sense to deal with
“Pulmonary circulation” (Chapter 16) before “Coronary circulation”
(Chapter17). The bibliography is updated and a glossary is added to the
present edition.
The authors are at their best when describing such aspects as pulse wave
generation, amplification, analysis, transmission and reflection,
impedances of the arterial system and pressure/flow relations. They are
internationally recognized experts in these fields and the chapters on
these topics are written in an admirably clear way. The content is easy to
understand, also for non real experts in the field. In the assessment of
the pressure/diameter relations to estimate the viscous properties of an
artery, the necessity of using recording systems with equal electronic
delay times is dealt with properly, but the necessity of assessing these
parameters at exactly the same site in the artery under investigation, to
avoid overestimation of the degree of hysteresis, and, hence, of the
viscous properties of the artery, should have been emphasized.
Chapters on endothelial cell (EC) function and atherosclerosis are
inevitably topics to be discussed in a book on “Blood flow in arteries.”
In these chapters the authors limit themselves to describing EC function
and its assessment, and to discussing general aspects of atherosclerosis
without addressing in detail the important role of biomechanical factors
in this function and in this disease. It has been well established that,
in addition to biochemical mediators, circumferential wall strain and wall
shear stress (WSS) are important determinants of EC function and EC gene
expression. The latter being dependent on the type and the level of WSS
the EC’s are exposed to. Atherosclerotic lesions preferentially start in
areas of disturbed flow, associated with low WSS which expresses an
atherogenic endothelial gene profile. The interaction between
biomechanical forces and EC function, called mechanotransduction, has been
the subject of investigation in the past 15 years. These studies have
provided a wealth of information on this intriguing mechanism. It is
recommended to address the interaction between biomechanical forces and EC
function and gene expression and their role in atherogenesis more
elaborately in future editions of the textbook, if any. This is especially
appropriate, because forces as circumferential strain and wall shear rate
(WSR) can be determined in vivo. In large arteries, WSR can be derived
from 3-D velocity profiles non-invasively recorded by means of ultrasound
or magnetic resonance imaging techniques. WSS is estimated from the
product of WSR and local blood viscosity. In the microcirculation WSR can
be derived from velocity profiles assessed by using fluorescently labeled
nanometer particles as velocity tracers; plasma viscosity being used to
estimate WSS. In both large arteries and arterioles, the WSR data derived
from these in vivo recorded profiles, which are generally flattened
parabolas, have been shown to be substantially higher (on the average more
than two-times) than those estimated on the basis of theory, assuming the
velocity profile to be fully developed to a parabola. It is a pity that
barely any attention is paid to these developments, while the authors cite
articles addressing these aspects. The authors state that the velocity
profile may change along the arterial tree to a parabolic shape, quoting
Tangelder and colleagues (page 39). The arteriolar velocity profiles
presented by Tangelder and colleagues, an example of which is shown in
figure 2.24, are not parabolic, but flattened parabolas with K factors
varying between 2.3 and 4.0, values significantly exceeding the value of
2.0 for a parabolic velocity profile.
The chapter on “Ultrasonic blood flow and velocimetry” (Chapter 8) needs
reconsideration with respect to fundamental concepts as spatial, temporal
and velocity resolution of Doppler systems and the suppression of
stationary reflections. Moreover, outdated techniques, like zero-crossing
interval histograms, are extensively discussed, while commonly used,
modern processing techniques, as Doppler autocorrelation and
cross-correlation, are not mentioned at all. The latter technique is of
interest, because it allows for velocity measurements without sacrificing
the high resolution of the echo mode. For information about the present
state of the art the reader should have been referred to “Doppler
Ultrasound” by Evans and McDicken, Wiley, 2000.
Despite these limitations McDonald’s Blood Flow in Arteries remains the
standard textbook on physics of the cardiovascular system for scientists
active in this field. In many ways the fifth edition is an improvement
compared with previous editions and it is highly recommended to those who
want to be up-to-date on the complex relation between pressure and blood
flow in arteries. It is commendable that again the authors have taken the
effort to write a new edition.
Robert S. Reneman and Arnold P.G.Hoeks
Maastricht University, the Netherlands
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