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Presidential address: Charles Darwin and vascular surgery

1997; Elsevier BV; Volume: 25; Issue: 1 Linguagem: Inglês

10.1016/s0741-5214(97)70316-1

1097-6809

Frank J. Veith,

Medical History and Innovations

Selection as President of The Society for Vascular Surgery is for me a singular honor, especially because it comes on the 50th Anniversary of this esteemed Society. However, this is a time of enormous upheaval in American medicine, and holding this office has also forced me to focus on the future of Vascular Surgery and how well it will survive these turbulent times. The resulting concern I have for the future of our specialty has prompted me to select Charles Darwin as the topic of my Presidential Address. It is certainly reasonable to wonder what possible relevance Darwin, the famous English naturalist and the father of the theory of evolution, could have to Vascular Surgery. In fact, the theory and principles of Darwin are important to our specialty, and I will explain why. Charles Darwin was born in 1808 to a wealthy medical family in Shrewsbury, England. His father, a fashionable physician, entered his young son in Edinburgh Medical School. However, young Charles fled in horror at the sight of his first operation. Because the choice of alternative careers was limited and his aptitude for the classics minimal, his father enrolled Charles in Christs' College at Cambridge University with the intent that he become a clergyman. At Cambridge, Darwin obtained the rudiments of a scientific education and was able to pursue his boyhood interest in the natural history of plants, birds, and insects. Indeed, until the defining event in Darwin's life, it appeared that he was destined to become yet another botanizing Victorian clergyman. That seminal event was his appointment as Naturalist on the naval ship, H.M.S. Beagle, which had been commissioned to make a surveying voyage of the unexplored nether regions of South America, including Patagonia and Tierra del Fuego (Fig. 1).This 40,000 mile, 5-year voyage included many adventure-filled inland expeditions that gave Darwin a view of the natural world from the Brazilian jungle to the peaks of the Andes. His observations led him to speculate about the relationship between extinct and contemporary species and to question the then-current view that animal and plant species, having been created by God in His infinite wisdom, are permanently fixed and immutable. Concepts born in Darwin's mind on the voyage of the Beagle, together with supporting evidence gathered on that trip, ultimately led to his definitive formulation of the theory of evolution in The Origin of Species By Means of Natural Selection, published 23 years after the voyage.1Darwin C The origin of species by means of natural selection or the preservation of favored races in the struggle for life. Penguin Books, New York1968Google Scholar Darwin was not one to rush prematurely into print and had spent the two decades between the formulation of his theory and its announcement in wrestling with potential objections and collecting supportive facts. This caution was based on Darwin's recognition that his theory would contradict religious thinking and would therefore elicit a storm of hostility and opposition. As Mark Twain would subsequently say: “Let a man proclaim a new principle and public sentiment will surely be on the other side.” This statement certainly applied to Darwin's theory in his era. It is often applicable today, and it may apply to parts of this Presidential Address. The theory of biologic evolution was not new. By Darwin's own count, evolutionary ideas had been put forth by more than 30 predecessors going back to the ancient Greeks. Others, including Diderot, Lamarck, and Darwin's own grandfather, had previously expressed evolutionary concepts only to have them greeted by theologic indignation and discredited in favor of divine creation of fixed species. Darwin's unique accomplishment was to accumulate a massive body of exemplary evidence, bolstered by the newly emerging scientific disciplines of geology and paleontology, to support his theory. He was also the first to have the crucial insight that the cause of evolutionary change must lie within the reproductive process, which produced random unlimited variations. These random heritable variations placed certain offspring in a favored position to cope with the Earth's constantly changing environment. Darwin postulated that these favored forms were better able to survive and would go on to form species, all members of which would have the new favorable trait. These new species would hold a competitive advantage and would win out over less-favored forms or species in the constant struggle for survival that exists throughout the animal and plant kingdoms. The less-favored forms or species would then diminish in numbers and become extinct. This process was Darwin's “Natural Selection.” Species that were most fit by virtue of a particular trait to cope with an ever-changing environment would displace other less fit or less capable related species. In the universal struggle for existence, the former would survive while the latter would not. To describe this process, Darwin adopted a phrase used in 1852 by Herbert Spencer: “survival of the fittest.” However, Darwin's use of the word “fittest” was in relation to a given environment and not on an absolute scale of perfection.2De Beer G Charles Darwin: evolution by natural selection. Doubleday & Co, Garden City, N.Y1964Google Scholar Other aspects of Charles Darwin's life are inheritantly fascinating. On March 26, 1835, Darwin was heavily bitten by the Benchuca or great black bug of the Pampas.3Darwin C Voyage of the beagle. Penguin Books, New York1989Google Scholar This “kissing bug” carries Trypanosoma cruzi, the causative agent of Chagas' disease. Although the disease was not known until long after Darwin's death, it is likely that this infestation produced the lassitude and the heart and gastrointestinal disorders that troubled Charles Darwin throughout his life after the Beagle. These symptoms and the resulting semi-invalidism caused Darwin to shun society and other amusements and distractions, thereby giving him the opportunity to concentrate more fully on his work. Darwin's scientific accomplishments were prodigious and not restricted to The Origin of Species. As shown in Table 1, his scientific interests spanned an enormous breadth within botany and zoology.Table IPublications of Charles Darwin and date of first appearanceJournal of Research Into Zoology and Natural History (during the Voyage of the Beagle)—1839Sketch of Species Theory—1842Structure and Distribution of Coral Reefs—1842Essay on Species—1844Geological Observations on Volcanic Islands—1844Geological Observations on South America—1846Multiple Monographs on Recent and Fossil Lepadidae and Balanidae (Barnacles and Acorn Shells)—1851–1854Joint Paper with A.R. Wallace on Evolution and Natural Selection—1858Origin of Species—1859Paper on Dimorphism in Primula (Primroses)—1862On the Various Contrivances by Which British and Foreign Orchids are Fertilized by Insects—1862Descent of Man—1871Expression of the Emotions in Man and Animals—1872Insectivorous Plants—1875Climbing Plants—1875Effects of Cross and Self-Fertilization in the Vegetable Kingdom—1876Different Form of Flowers on Plants of the Same Species—1877Role of Erasmus Darwin—1879Power of Movement of Plants—1880Formation of Vegetable Mold Through the Actions of Worms—1881Autobiography—1887 (Published after his death as part of Life and Letters of Charles Darwin) (Charles Darwin died April 19, 1882) Open table in a new tab Although some of his secondary works were related to his primary interest in evolutionary theory, others described innovative concepts regarding the formation of volcanic islands and coral reefs, the mechanisms of plant fertilization and reproduction, the power of movement in climbing and insectivorous plants, and landmark studies of the natural history of earthworms and barnacles. In time many of these concepts would become classics. After seriously debating with himself the pros and cons of marriage and its impact on his scientific career, Charles Darwin on January 28, 1939, at age 30, married his cousin, Emma Wedgewood, the daughter of the famous pottery maker Josiah Wedgewood (Fig. 2, Fig. 3).Fig. 3Emma Darwin, 1840. From a portrait by George Richmond.View Large Image Figure ViewerDownload Hi-res image Download (PPT)He rationalized his marriage with the following: “My God, it is intolerable to think of spending one's whole life, like a neuter bee, working, working, and nothing after all. No, no, won't do … Marry, Marry, Marry Q.E.D.”2De Beer G Charles Darwin: evolution by natural selection. Doubleday & Co, Garden City, N.Y1964Google Scholar After marriage, Charles and Emma Darwin, who had 11 children, lived in London for 4 years. They then moved to a country home, Down House in Kent, where he wrote most of his books and articles (Fig. 4).Fig. 4Charles Darwin, 1854. From a photograph by Maull and Fox.View Large Image Figure ViewerDownload Hi-res image Download (PPT)Although Darwin's poor health was ascribed to hysteria, anxiety, and hypochondriasis, it is unlikely that a man with the physical stamina, fortitude, and bold spirit he showed during the arduous and adventure-filled voyage of the Beagle could be afflicted with these neuroses. The Benchuca and Chagas disease are far more likely explanations for the ill health that formed a backdrop for Darwin's work from the end of 1839 until his death at age 73 on April 19, 1882. What human qualities best define Charles Darwin? The keynote of his character was simplicity. His wife described him as “the most open, transparent man I ever saw. …” Darwin characterized himself as “a great overgrown child” committed to happy endings. He despised cruelty to man and animals, but he recognized that animal experimentation was important for scientific progress, which, in turn, he believed was essential to the betterment of mankind. In the latter part of his life, his religious beliefs centered around natural scientific laws rather than a Creator with unlimited power and compassion. Darwin's self-appraisal of his mental qualities indicated that he “had become skillful in guessing right explanations and devising experimental tests. …” He believed he had “no quickness of apprehension or wit …” but that he was “superior to the common run of men in noticing things which easily escape attention, and in observing them carefully.” He attributed his success in science to “methodical habits, ample leisure from not having to earn my bread … and ill health, … love of science, unbounded patience, industry in observing and collecting facts, and a fair share of invention [and] … common sense.”2De Beer G Charles Darwin: evolution by natural selection. Doubleday & Co, Garden City, N.Y1964Google Scholar Apart from the ill health, all these qualities would serve an aspiring young vascular surgeon well today. Despite the turmoil and controversy his theories had created, on his death the greatness of Charles Darwin and the revolutionary importance of his theory to the biologic sciences were recognized (Fig. 5).He was likened to Copernicus, Newton, and Faraday and was buried with appropriate honors in Westminister Abbey. Before considering the uncanny relevance of Darwinian principles to Vascular Surgery, it is important to examine some of the forces of change ongoing in its medical environment. All of these threaten the status quo, and some are threatening to the very existence of Vascular Surgery as a specialty. These forces have been fully discussed elsewhere,4Veith FJ. The E. Stanley Crawford Critical Issues Forum 1995: the future of vascular surgery in a changing world.J Vasc Surg. 1996; 23: 894-895Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar, 5Veith FJ The Society for Vascular Surgery: a look at the future.J Vasc Surg. 1996; 24: 144-147Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar but some bear reemphasis. The financial support structure for medical care is changing. To restrain escalating health costs, government funding is being curtailed and managed care systems are being introduced widely. These systems provide financial disincentives to use invasive treatments, such as those required by some vascular disease patients. They also tend to place control of the use of these procedures in the hands of generalists rather than the specialists who perform them. All of these changes will make it difficult for the vascular surgeon specialist to function and will increase competition for the reduced dollars that are available to provide care for vascular disease patients. A second major environmental change is the introduction of technologic improvements that permit less-invasive, more cost-effective treatments. In the vascular disease area this involves a host of endovascular treatments with catheters, balloons, atherectomy devices, stents, stented grafts, and various derivative devices. All of these endovascular treatments involve catheter-guidewire-imaging techniques. All are potentially threatening to vascular surgeons because they may prove equal to or better than open surgical treatments and because they may be administered by nonsurgical interventional specialists with background training in Radiology or Cardiology. Competition of these other specialists with vascular surgeons for patients and limited health care dollars is inevitable. Moreover, interventional radiologists and cardiologists sincerely believe their access to new catheter-based treatments justifies their expanding role in the management of patients who were previously cared for by vascular surgeons.6DeMaria AN Peripheral vascular disease and the cardiovascular specialist.J Am Coll Cardiol. 1988; 12: 869-870Abstract Full Text PDF PubMed Scopus (11) Google Scholar, 7Kinnison ML White RI Auster M et al.Inpatient admissions for interventional radiology: philosophy of patient management.Radiology. 1985; 154: 349-351Crossref PubMed Scopus (37) Google Scholar, 8Katzen BT van Breda A Developing an interventional radiology practice.Semin Intervent Radiol. 1988; 5: 99-102Crossref Scopus (7) Google Scholar, 9Kerlan RK Marone T Ring EJ The clinical role of the interventional radiologist.Semin Intervent Radiol. 1988; 5: 103-104Crossref Scopus (9) Google Scholar, 10Cook JP Dzau VJ The time has come for vascular medicine.Ann Intern Med. 1990; 112: 138-139Crossref PubMed Scopus (25) Google Scholar Ever-increasing expansion of the workforce in these nonsurgical specialties and decreasing workloads provide further impetus for them to increase their activities in the realm of vascular disease treatment. A third change in the challenging environment that vascular surgeons face is the re-entrance of general surgeons into the vascular disease treatment field. Decreasing workloads in traditional general surgical procedures, the emphasis on generalist care, and the current antispecialty aura has prompted some leaders in general surgery to advocate broadening the training and role of general surgeons so that they can provide “expertise that at the present time is attributed to various subspecialties, both within and without the realm of traditional general surgery” and can “practice to the fullest extent of the specialty.”11Ritchie Jr, WP What the future may hold for general surgery: a position paper of the American Board of Surgery.J Am Coll Surg. 1995; 180: 481-484PubMed Google Scholar This is a call to reverse the recent trend for younger general surgeons without special training and certification in Vascular Surgery to not perform vascular procedures.12Wheeler HB Should vascular surgery become an independent specialty? implications of data about operative experience.J Vasc Surg. 1990; 12: 619-628Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar, 13Stanley JC Barnes RW Ernst CB Hertzer NR Mannick JA Moore WS Vascular Surgery in the United States: workforce issues—report of the Society for Vascular Surgery and the International Society for Cardiovascular Society, North American Chapter, Committee on Workforce Issues.J Vasc Surg. 1996; 23: 172-181Abstract Full Text PDF PubMed Scopus (100) Google Scholar If this call were heeded, it would negate the purpose of specialized training in Vascular Surgery, namely the provision of better care to vascular disease patients.14Wylie EJ Presidential address: vascular surgery—a quest for excellence.Arch Surg. 1970; 101: 645-648Crossref PubMed Scopus (31) Google Scholar, 15DeWeese JA Blaisdell FW Foster JH Optimal resources for vascular surgery.Arch Surg. 1972; 105: 948-961Crossref PubMed Scopus (42) Google Scholar, 16DeWeese JA Presidential address: vascular surgery—Is it different?.Surgery. 1978; 84: 733-738PubMed Google Scholar Vascular Surgery came into being as a specialty when it became obvious that general surgeons and cardiothoracic surgeons were not achieving optimal results with vascular operations.14Wylie EJ Presidential address: vascular surgery—a quest for excellence.Arch Surg. 1970; 101: 645-648Crossref PubMed Scopus (31) Google Scholar, 15DeWeese JA Blaisdell FW Foster JH Optimal resources for vascular surgery.Arch Surg. 1972; 105: 948-961Crossref PubMed Scopus (42) Google Scholar, 16DeWeese JA Presidential address: vascular surgery—Is it different?.Surgery. 1978; 84: 733-738PubMed Google Scholar The improved results of vascular operations, when performed by well-trained surgeons who focus their attention on them and perform them in adequate numbers, has been amply documented by a plethora of studies that are well summarized by Hertzer.17Hertzer NR Presidential address: outcome assessment in vascular surgery—results mean everything.J Vasc Surg. 1995; 21: 6-15Abstract Full Text Full Text PDF PubMed Scopus (65) Google Scholar To apply the theory and principles of Darwin to Vascular Surgery in its present changing environment demands that we equate a “medical specialty” to a “species.” The validity of this equivalence becomes apparent if we recognize that species may be defined as a group of individual plants or animals that all have a high degree of similarity, can generally interbreed or reproduce only among themselves, and that show persistent differences from allied species.1Darwin C The origin of species by means of natural selection or the preservation of favored races in the struggle for life. Penguin Books, New York1968Google Scholar, 18Webster's New World Dictionary. Second College Edition. World Publishing Co, New York1970Google Scholar A medical specialty may be defined as a group of individual doctors of medicine who, as a result of specialized effort and training in a defined field, have a high degree of similarity in their possession of a special, distinct body of scientific medical knowledge and technical ability that is not possessed in full by other specialists.19Annual Report & Reference Handbook—1996. American Board of Medical Specialties, Research and Education Foundation, Evanston, Ill1996: 106-108Google Scholar They concentrate their practice in the well-defined and distinct area of their special knowledge and technical ability, and they have the capacity to reproduce themselves via recognized residency training programs with a defined curriculum and specified case and procedural experiences.19Annual Report & Reference Handbook—1996. American Board of Medical Specialties, Research and Education Foundation, Evanston, Ill1996: 106-108Google Scholar Among the objectives of recognized medical specialties and their governing bodies or boards is that they act in the public interest by contributing to the improvement of medical care by establishing qualifications and by evaluating individuals who apply for certification.20Annual Report & Reference Handbook. 1996: 73Google Scholar Establishment of new medical specialty boards “must be based on major new concepts … or substantial advancement in medical science. [They] must represent a distinct and well-defined field of medical practice.”21Annual Report & Reference Handbook. 1996: 74Google Scholar Vascular Surgery incorporates a discrete body of knowledge and distinct skills. Many are major new advances. It differs from other specialties, and its members reproduce themselves by recognized residency programs in vascular Surgery. It, therefore, qualifies as a separate species or medical specialty. Darwin's theory and principles of evolution and natural selection are particularly relevant to Vascular Surgery if we realize that medical specialties, like species, are engaged in a constant struggle for existence and survival. Our specialty, Vascular Surgery, is in competition with other specialties, Interventional Radiology and Cardiology, for the patients that are the wherewithall to survive and flourish. This competition is rendered more fierce by some of the previously noted forces of change that exist in our environment. These forces will also place us in competition with our more closely related progenitor specialty, General Surgery. The outcome of this competition and struggle for existence will be survival and flourishing with increased numbers for some specialties; for others it will be weakening and diminished numbers; for still others it will mean extinction. Although the pollyannas may say there will be work for all, medical specialties, like species and individuals, have an irresistible urge to procreate and generally exercise minimal restraint of their excessive reproductive capacity. This leads to unchecked increases in the numbers of individuals within a well-adapted species/specialty, which, as Darwin noted, assures the extinction of less-well-adapted forms that are competing for the same niche in the environment.1Darwin C The origin of species by means of natural selection or the preservation of favored races in the struggle for life. Penguin Books, New York1968Google Scholar This niche is defined by food supply and habitat in the case of an animal species and by patients in the case of a medical specialty. Thus the universal struggle for existence inevitably follows from the high rate at which all organic beings and medical specialists tend to increase. Although some suggestions have been made to limit the numbers of medical specialty trainees, these efforts have been limited by antitrust laws and by the obvious incentives, such as prestige and low-cost assistance, that accrue to individuals who direct training programs. Because a changing environment can and has in the past produced the extinction of innumerable species and some medical specialties and because such extinction is a consequence of poor adaptation to a changing environment, what can Vascular Surgery and vascular surgeons do to assure the survival of their specialty in the present circumstances? They must recognize that their species or specialty is not immutable or fixed by some Creative Power, but must constantly evolve to survive. Moreover, they must realize, as Darwin showed, that transmutation of species is the rule and that several current species or specialties may descend from a common ancestor or progenitor. In the case of surgical specialties, they have all descended from a common progenitor specialty, General Surgery, to become clearly defined and separate specialties. This has been the case for Neurosurgery, Orthopedics, Urology, Plastic Surgery and Cardiothoracic Surgery. It must also be so for Vascular Surgery, if it is to survive. Vascular surgeons must also recognize the applicability of the Darwinian principle that forms that most resemble the common ancestors of several current species or specialties often become extinct as their superior and better-adapted progeny with favorable variations displace them in the endless struggle for existence.1Darwin C The origin of species by means of natural selection or the preservation of favored races in the struggle for life. Penguin Books, New York1968Google Scholar Darwin's principle of divergence also applies to medical specialties as well as species. According to this principle, differences between species or specialties that are at first barely perceptible tend to increase steadily, causing the different species or specialties to diverge increasingly in character both from each other and from their common progenitor.1Darwin C The origin of species by means of natural selection or the preservation of favored races in the struggle for life. Penguin Books, New York1968Google Scholar After vascular surgeons recognize that Darwinian theory applies to medical specialties as well as species throughout nature, they must then address three specific issues to minimize the risk of extinction. There are two clear reasons why vascular surgeons must become competent with the catheter-guidewire-imaging techniques that will enable them to perform endovascular treatments. The first is that some of these treatments will prove to be safe and effective and will replace standard open surgical techniques. This is already true for percutaneous balloon angioplasty (PTA) and caval filters. As stents, endovascular grafts, and other newer treatments become perfected, it is possible that 40% to 70% of current operations will be replaced with less-invasive endovascular treatments.22Veith FJ Presidential address: transluminally placed endovascular stented grafts and their impact on vascular surgery.J Vasc Surg. 1994; 20: 855-860Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar, 23Veith FJ Marin ML Endovascular surgery and its effect on the relationship between vascular surgery and radiology.J Endovasc Surg. 1995; 2: 1-7Crossref PubMed Scopus (15) Google Scholar The survival of Vascular Surgery will depend on the ability of vascular surgeons to adapt and acquire the catheter-guidewire-imaging skills to perform some of the new endovascular procedures that replace vascular operations. If we do not, the need for our services will decrease, we will gradually be replaced, and our numbers will diminish heading toward eventual extinction. As Darwin noted, the “death of a species [specialty] is a consequence of non-adaptation to [changing] circumstances.”1Darwin C The origin of species by means of natural selection or the preservation of favored races in the struggle for life. Penguin Books, New York1968Google Scholar It is true that some endovascular procedures are done efficiently by other interventional specialists. Accordingly, it should not be our goal to “take back” diagnostic angiography or the simple catheter-directed treatments that are currently performed mostly by interventional radiologists. To do so is unnecessary and will lead to destructive turf battles.22Veith FJ Presidential address: transluminally placed endovascular stented grafts and their impact on vascular surgery.J Vasc Surg. 1994; 20: 855-860Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar, 23Veith FJ Marin ML Endovascular surgery and its effect on the relationship between vascular surgery and radiology.J Endovasc Surg. 1995; 2: 1-7Crossref PubMed Scopus (15) Google Scholar However, it is the newer endovascular procedures, many that require surgical as well as endovascular skills, that will replace a large proportion of vascular operations. It is these that vascular surgeons must be able to perform to survive and flourish. Most endovascular grafting and some complex stenting procedures that are performed with an open vascular component are typical examples. A second reason to acquire endovascular skills is that they can be effectively used to simplify and improve a variety of standard vascular operations. Fluoroscopically assisted thromboembolectomy is an example.24Parsons R Marin ML Veith FJ et al.Fluoroscopically assisted thromboembolectomy: an improved method for treating acute occlusions of native arteries and bypass grafts.Ann Vasc Surg. 1996; 10: 201-210Abstract Full Text PDF PubMed Scopus (29) Google Scholar Using intraoperative digital C-arm fluoroscopy, a variety of guidewires and double-lumen balloon catheters, it is now possible to perform safer, better thromboembolectomy of even heavily diseased arteries. This technique facilitates over-the-wire passage of the balloon catheter through tortuous, stenotic, clot-filled arteries. It permits visual control of the contrast-filled balloon as it is drawn through diseased arteries to remove the clot, thereby avoiding damage to diseased and normal arteries. It also facilitates complete clot removal and localization and minimally invasive endovascular treatment of significant inflow and outflow lesions.24Parsons R Marin ML Veith FJ et al.Fluoroscopically assisted thromboembolectomy: an improved method for treating acute occlusions of native arteries and bypass grafts.Ann Vasc Surg. 1996; 10: 201-210Abstract Full Text PDF PubMed Scopus (29) Google Scholar Intraoperative digital fluoroscopy and catheter-guidewire techniques also facilitate other vascular operations. These techniques enable over-the-wire balloon control of inflow or outflow arteries when infection, scarring, or location renders traditional surgical access difficult. A good example is a case with subclavian artery injury. These techniques allow precise localization of pressure gradients and they facilitate simple endovascular treatment of unexpected lesions. They can also provide more accurate, more complete intraoperative angiograms of arterial reconstructions along with their entire inflow and outflow tracts. With cinefluoroscopy,