Partial and total artificial hearts The first observation that the work of the heart could be temporarily replaced by a pump, such as the DeBakey roller pump, established the ground-work f
Trang 1Congress in 1956 Dr DeBakey has continued
a life-long involvement with the library, serving
first as a board member and later as its chairman
Being especially sensitive to the medical needs
of soldiers, Dr DeBakey also proposed the
creation of medical centers designed exclusively
for veterans The first Veterans Administration
Hospital was established in Houston in 1949 on
the recommendation of Dr DeBakey In
recogni-tion of his contriburecogni-tions to the welfare of
vet-erans, in 2003 the Michael E DeBakey Veteran’s
Administration Medical Center at Houston was
named in his honor
Career at Baylor College of Medicine
In 1948, Dr DeBakey accepted the position of
chairman of the department of Surgery at Baylor
University College of Medicine, now Baylor
College of Medicine There, his talent for
organi-zational innovation led to numerous
develop-ments Dr DeBakey’s protean interest and
abilities were applied in many areas As a result
of his administrative talents and leadership, by the
early 1950s, Baylor had become one of the leading
medical schools for surgical innovation A seminal
contribution to this field was Dr DeBakey’s
pioneering work in repairing arterial aneurysms
with Dacron grafts[3–14] Nearly every aspect of
cardiovascular surgery was influenced by his
tire-less work ethic and innovative mind To address
the subject of this monograph, however, the
re-maining comments are confined to Dr DeBakey’s
role in the development of mechanical circulatory
support devices for advanced heart failure
Partial and total artificial hearts
The first observation that the work of the heart
could be temporarily replaced by a pump, such as
the DeBakey roller pump, established the
ground-work for mechanical circulatory assistance
An-other important observation reported by Dr
DeBakey [15] was the potential for recovery of
the failed heart by simple prolongation of
cardio-pulmonary bypass These two observations
advo-cated by Dr DeBakey (ie, the ability of
circulatory support to replace heart function and
the ability of the heart to recover following
‘‘car-diac rest’’ by mechanical assistance) formed the
basis of all subsequent developments in the field
At Baylor, Dr DeBakey energetically created
a team of the most talented physicians and
researchers to aid in the developmental work of
cardiac-assist devices Two of the leading
researchers in this field were Dr William Hall and Dr Domingo Liotta As a Baylor student, I had the privilege of working with Dr Hall and
Dr Liotta, and, in 1965, I wrote a student re-search paper on cardiac support devices, which was based on my work with these two leaders Significant research in this field would have been impossible, however, without government funding, which sustained the development of future cardiac-assist devices Recognizing this,
Dr DeBakey[16–18]took his message to Wash-ington In 1963, he spoke before Congress about the need for a total artificial heart, and his testi-mony was instrumental in persuading the Na-tional Institutes of Health to establish the Artificial Heart Program (1964) to support the de-velopment of such a device (Fig 1)
Throughout the 1960s, researchers in the Baylor Surgical Laboratories were known for their leadership in the field of mechanical circula-tory support, which was due in part to funding received from the National Institutes of Health
On July 18, 1963, after years of research with animal models, Dr DeBakey performed the first successful clinical implant of a left ventricular
Fig 1 Michael E Debakey, MD, circa 1963 (Courtesy
of O.H Frazier, MD, Houston, TX.)
Trang 2Expectations of Surgeons from an Imager
University of Pennsylvania Medical Center, Philadelphia, PA, USA
Congestive heart failure is a clinical syndrome
characterized by fatigue, shortness of breath,
exercise intolerance, and fluid retention with lower
extremity and/or pulmonary edema There is an
estimated 25 to 30 million patients who have heart
failure worldwide Heart failure is primarily
a disease of the elderly, and the prevalence of
chronic heart failure increases with advancing age
Currently, chronic heart failure is the most
common hospital discharge diagnosis in patients
over the age of 65 years Thus, as the population
ages, the management of heart failure will become
more frequent and of even greater importance
The management of patients who have heart
failure is challenging, and the mortality with
medical therapy alone is high Although the ideal
treatment for heart failure is cardiac
transplanta-tion, this therapy is limited by a chronic shortage
of donor hearts Currently, the mainstay of heart
failure treatment is pharmacologic and includes
angiotensin converting enzyme inhibitors,
angio-tensin receptor blockers, b-adrenergic receptor
blockers, aldosterone receptor antagonists,
di-uretics, and digitalis However, surgery is
becom-ing increasbecom-ingly important with valve repair/
replacement, ventricular assist devices, and
epi-cardial restraints
Systolic versus diastolic heart failure
Heart failure may be systolic due to abnormal
myocardial excitation–contraction coupling or
di-astolic due to abnormal relaxation and increased
myocardial passive stiffness Between 30% and 50% of all patients presenting with heart failure have diastolic heart failure (left ventricle [LV] ejec-tion fracejec-tionR50%) Diastolic heart failure was initially believed to be a rare and benign condition, but the annual mortality from diastolic heart fail-ure ranges from 5% to 15%, and admission rate for recurrent heart failure is 50% within the first
6 months[1–4] The remaining 50% to 70% of pa-tients present with systolic heart failure that is clinically indistinguishable from diastolic heart failure It is important to identify patients who have systolic heart failure because they may be el-igible for surgical therapy The important informa-tion in systolic heart failure for the surgeon from
an imaging perspective is the reliable and repro-ducible assessment of LV size, architecture, and function, because these are the strongest predictors
of clinical outcome following cardiac surgery We therefore focus attention on systolic heart failure and how imaging modalities can optimize the type and timing of surgical treatment
Assessment of left ventricle function There are several different imaging modalities available for qualitative and quantitative assess-ment of LV function: echocardiography, nuclear imaging, contrast angiography, cardiac magnetic resonance (CMR) imaging, and CT CMR is considered the gold standard for estimation of
LV volumes, mass, and function (LV ejection fraction [LVEF]), because of its high spatial and temporal resolution and its ability to quantify
LV volume from tomographic slices without geo-metric assumptions regarding LV cavity shape (Fig 1) However, echocardiography is more commonly used than CMR in clinical practice for assessment of LV volumes and function be-cause of its wider availability Echocardiography
* Corresponding author Division of Cardiology,
University of Pennsylvania Medical Center, 3400 Spruce
Street, Philadelphia, PA 19104.
E-mail address: suttonm@mail.med.upenn.edu
(M St John Sutton).
1551-7136/07/$ - see front matter Ó 2007 Elsevier Inc All rights reserved.
doi:10.1016/j.hfc.2007.04.002 heartfailure.theclinics.com
Heart Failure Clin 3 (2007) 121–137