sasagsasR including particularly arteriosclerosis, which is by far

43 Pages·2007·20.87 MB·English

707
BASIC CONCEPTS OF THERAPY
IN ARTERIAL DISEASE*
MICHAEL E. DE BAKEY
Professor and Chairman, The Cora and Webb Mading Department of Surgery
Baylor University College of Medicine, Houston, Texas
TRHUGHOUT the Western World, arterial diseases rank
among the most common ailments of man, accounting
for deaths than all other diseases combined. De-
more
spite the fact that the cause of most of these diseases,
|sasagsasR including particularly arteriosclerosis, which is by far
the most common, remains obscure or undetermined, great progress
has been made in recent years toward development of better under-
standing of the insidious pathologic-anatomic changes that occur in
the arterial wall, more precise methods of diagnosis, and more effective
therapy. Indeed, greater advances have been made in this field of en-
deavor during the past decade alone than in all previous years of
recorded history.
A number of factors are responsible for this striking progress, most
important among which are: i) the development of relatively safe and
readily applied methods of angiography which, by providing roentgen-
ographic visualization of the arterial tree, permit precise delineation
not only of the location, nature, and extent of the diseased area, but
also of its effect upon the distal arterial circulation; 2) the development
of highly successful methods of vascular surgery, including the use of
vascular replacements, which, depending upon the nature of the lesion,
may be directed toward overcoming its occlusive effects with restora-
tion of normal circulation or toward removal of the diseased segment
and its replacement with an arterial substitute; and 3) a tremendous surge
of interest and increasing intensity of research endeavors, both clinical
and experimental, which have undoubtedly received great impetus from
the initial development of an effective medical and surgical therapeutic
approach to some of these problems that had long seemed hopeless.
* The 1963 Albert Lasker Clinical Research Awtard Lecture, presented at The Nesv York Academy
of Medicine, October 30, 1963.
This paper appears simultaneously in the Journal of the American Medical Association of Novem-
ber 2, 1963.
Vol.39, No. 11, November1963
7 0 8 M. E. DE BAKEY
70 M.E E AE
Fig. 1. (a) Drawing of characteristic arteriosclerotic aneurysm of abdominal aorta
arising just below renal arteries and involving bifurcation and both common iliac
arteries in a 56-year-old white man. (b) Drawing showing surgical procedure consist-
ing of resection of aneurysm and replacement with abdominal aortic bifurcation homo-
graft. (c) Lumbar aortogram made approximately ten years after operation showing
normal functioning homograft. Patient has remained asymptomatic and has been
working regularly since operation.
As a result of these more intensive investigations, certain concepts
have been developed concerning diseases of the aorta and major arteries
that provide the basis for rational and more effective therapy. Most
important among these has been the emphasis placed upon the ana-
tomic-pathologic characteristics of the lesion itself and its hemodynamic
functional effects rather than upon its causation. From studies along
these lines, the concept has evolved that, regardless of etiology, the
lesion in many forms of aortic and arterial disease may be well local-
ized and segmental in nature with a relatively normal, patent proximal
and distal arterial bed. The great significance of this concept lies in
the fact that it has provided the means to leap across the etiological
wvall, which for most of these diseases has remained unassailable, to
reach the ultimate objective of effective therapy.
Thus, on the basis of this concept it becomes possible to classify
most, if not all, arterial diseases into two major categories: aneurysms
and occlusive lesions. In both categories the lesions may be of con-
Bull.N.Y.Acad.Med.
BASIC CONCEPTS OF THERAPY IN ARTERIAL DISEASE 70
Fig. 2. (a) Drawing and aortogram showing characteristic location of traumatic
aneurysm of thoracic aorta resulting from injuries sustained in an automobile accident
in a 44-year-old white male patient. Ten years previously, operation consisting of
cellophane wrapping of the aneurysm was performed elsewhere. For the past eight
years patient has complained of substernal pain which had become progressively worse
in recent months along with increase in size of aneurysm. (b) Drawing with super-
imposed photograph (left) made at operation showing operative procedure consisting
of resection of aneurysm and replacement with dacron graft. Aortogram (right) made
about one year after operation shows restoration of normal aortic continuity and
function. Patient has had no complaints and has resumed normal activities.
Vol.39,No. 11,November 1963
i::: . . .
; :
Fig. 3. (a) Drawing and preoperative aortogram showing location and extent ot
typical syphilitic aneurysm of thoracic aorta in a 43-year-old white man, who comi-
plained of severe left chest pain, hoarseness, dyspnea, and a brassy cough. Aneurysm
was treated by resection and homograft replacement. (b) Drawing and aortogram
made approximately eight years after operation showing development of aneurysm
in homograft. (c) Drawing and aortogram. made about one year after second operation,
consisting of resection of aneurysmal homograft and replacement with dacron graft,
showing restoration of normal continuity and function of thoracic aorta. Patient has
remained asymptomatic and engages in normal activities since first operation.
BASIC CONCEPTS OF THERAPY IN ARTERIAL DISEASE 7 'I
Fig. 4. (a) Drawing and (b) preoperative aortogram showing extensive dissecting
aneurysm arising just distal to left common carotid artery and involving entire
descending thoracic aorta in a 55-year-old white woman complaining of severe chest
pain. (c) Drawing showing operative procedure consisting of resection of dissecting
aneurysm and replacement with dacron graft. (d) Postoperative aortogram showing
restoration of normal continuity and function of thoracic aorta. Patient has remained
well and has resumed normal activities for past year since operation.
Vol.39,No. 11,November 1963
Fig. 5. (a) Drawing and (b) preoperative aortogram showing typical coarctation of
aorta in a 35-year-old white man complaining of throbbing headaches, palpitation, and
easy fatigability. (c) Drawing showing application of bypass principle employing
dacron graft attached by end-to-side anastomosis to left subclavian artery above and
to descending thoracic aorta below coarcted segment. (d) Postoperative aortogram
showing restoration of normal aortic circulation through bypass graft. During past
year since operation patient has remained asymptomatic with normal blood pressure in
both upper and lower extremities.
BIASIC CONCEPTS OF THERAPY IN ARTERIAL DISEASE 7 I 3
genital, acquired, or traumatic origin, but from the practical therapeutic
standpoint and particularly in terms of the surgical approach to the
problem, the nature, location and extent of the lesion itself or the result-
ant hemodynamic disturbances assume greater significance than these
etiologic factors. Thus, an aneurysm of the aorta may be of arterio-
sclerotic (Fig. i), traumatic (Fig. 2), syphilitic (Fig. 3), or dissecting
(Fig. 4) origin, and although these etiologically different problems
deserve further study directed toward their solution, of greater imme-
diate and practical significance is the fact that all of these lesions have
a similar, ultimately fatal course that can be effectively corrected by
similar principles of surgical treatment. This may be further exemplified
by the fact that the etiologic considerations of an occlusive lesion of
the aorta of congenital origin, such as coarctation (Figs. 5, 6), or of
arteriosclerotic origin, such as in Leriche's syndrome (Fig. 7), or
even of some undetermined arteriopathy (Fig. 8) have less immediate
significance than the fact that in all instances the resultant hemodynamic
disturbances of the lesions and their characteristic segmental involve-
ment are similar, permitting the application of similar principles of sur-
gical therapy. Of particular interest in this connection is the fact that
in both of these major categories of arterial disease, i.e., aneurysms and
occlusions, the most common etiologic factor is arteriosclerosis or
atherosclerosis, and combined forms of these lesions often occur in the
same patient (Figs. 9, I0, 22).
Another important development in our concept of the nature of
arterial diseases lies in the tendency of both aneurysmal and occlusive
forms to assume certain characteristic anatomic, pathologic, and clin-
ical patterns of involvement. The earlier prevailing belief that arterio-
sclerosis was a degenerative and diffuse disease has been largely dis-
pelled since it is now well established that this disease often tends to
be well localized and segmental in nature, with relatively normal patent
channels immediately proximal and distal to the lesion, even in patients
with extensive involvement and multiple sites of occurrence (Figs. 9-
iI). This important characteristic feature of the lesion has also been
demonstrated in arterial occlusive diseases of other than arteriosclerotic
origin, such as those termed thromboangiitis obliterans (Fig. 12) and
nonspecific arteritis (Fig. I3).
This concept, which places emphasis upon the characteristic ana-
tomic-pathologic features of the disease to assume segmental involve-
Vol.39,No. 11,November 1963
7 I 4 M. E. DE BAKEY
714 M. k. DE BAKEY
Fig. 6. (a) Drawing and aortogram showing abdominal coaretation with severe steno-
sis of both renal arteries in a 20-year-old white woman with manifestations of severe
hypertension (blood pressure in upper extremities 190/120 mm. Hg and 90 mm.
Hg systolic in lower extremities) and intermittent claudication of lower extremities.
(b) Drawing showing operative procedure employed in patient consisting of application
of bypass principle using dacron grafts attached by end-to-side anastomosis to descend-
ing thoracic aorta above and to abdominal aorta below coarcted segment and then
to both renal arteries distal to stenotic areas. Aortogram on right made approximately
six months after operation shows restoration of normal circulation through bypass
grafts to both renal arteries as well as to distal abdominal aorta. For past year since
operation patient has remained normotensive and asymptomatic.
Bull.N.Y.Acad. Med.
BASIC CONCEPTS OF THERAPY IN ARTERIAL DISEASE 7 I 5
ment, provides the basis for classifying into four major categories most,
if not all, arterial occlusive diseases producing clinical patterns of vas-
cular insufficiency. The first category is concerned with lesions involv-
ing the major branches of the aortic arch. Two characteristic patterns
may be recognized; namely, a proximal form, involving the major
arteries arising from the aortic arch (Figs. 8, 13), and a distal form,
involving the internal carotid and vertebral arteries at their respective
origins (Figs. IO, II, 14). The occlusive process may be complete or
incomplete and multiple lesions are present in over half the cases. Par-
ticularly significant is the fact that the occlusive process in the proximal
form, whether complete or incomplete, is usually well localized with a
relatively normal distal arterial bed and therefore is operable in most
eases (Fig. 8). While this is also true for incomplete occlusive lesions
in the distal form, complete occlusions of long duration in this form
are usually not operable (Fig. io).
Although these different forms of occlusive lesions tend to produce
typical patterns of clinical and neurologic disturbances, it is important
to observe that in an appreciable number of cases they do not reflect
the exact nature, site, and extent of involvement of the occlusive
process. In some patients, for example, having characteristic ischemic
disturbances of occlusion of the internal carotid arteries, complete
arteriographic studies may reveal the responsible and surgically correc-
tible lesion to be in the vertebral arteries, while similar studies in other
patients with characteristic manifestations of basilar artery insufficiency
may reveal the responsible and surgically correctible lesion to be in the
internal carotid arteries (Fig. iI). Several reasons may exist for these
apparent discrepancies in the correlation of clinical manifestations with
the site and extent of the occlusive process, including particularly the
frequency of multiple involvement and the presence of collateral
circulation.
We have thus, on the basis of our observations, developed a con-
cept of the totality of cerebral blood flow. The brain receives its
arterial blood supply from four major systems: the two vertebral arteries
(which form the basilar artery) and the two internal carotid arteries.
Both extracranially and intracranially, these systems may communicate
with each other through major collateral channels. Thus, the brain may
derive its blood supply not only from the major arteries but from col-
lateral communications, and a gradual reduction in blood flow through
Vol.39,No. 11,November1963
7 i 6 M. E. DE BAKEY
Fig. 7. (a) Drawing and preoperative aortogram in 64-year-old white male patient
with severe intermittent claudication of lower extremities, showing complete occlusion
of abdominal aorta arising just distal to origin of renal arteries and extending distally
to involve both common iliac arteries. (b) Drawing showing application of bypass
principle using dacron graft attached by end-to-side anastomosis to abdominal aorta
above and to both common femoral arteries below occluded segment. This simple
and effective procedure was employed in this patient in order to avoid hazardous dis-
section of extensive scarring and adhesions overlying occluded segment of abdominal
aorta resulting from an unsuccessful operation previously performed elsewhere. Aorto-
gram on right made about two years after operation shows restoration of normal
circulation through bypass graft to both lower extremities. Patient is asymptomatic
and has resumed normal activities.
a major artery tends to enhance this compensatory development.
Ischemic disturbances may then become apparent only when the col-
lateral circulation is inadequate to meet the demands of the tissues it
supplies. This, of course, is the well-known explanation for intermittent
claudication of the lower extremities. It also applies for other organs
of the body, including the brain.
Still another important conceptual consideration in relation to this
problem of cerebrovascular insufficiency is concerned with the distinc-
Bull.N.Y.Acad.Med.