THE ROLE OF SURGERY IN HEART FAILURE - part 2 pps

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THE ROLE OF SURGERY IN HEART FAILURE - part 2 pps

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Congress 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 contributions 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.) 118 FRAZIER Expectations of Surgeons from an Imager Hind Rahmouni, MD, Martin St. John Sutton, MD, FRCP * 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 increasingly 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 fractionR50%). 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 . 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. 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. 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

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