Cardiac Surgery

Abstract

Well into the first decades of the 20th century, medical opinion held that any surgical attempts to treat heart disease were not only misguided, but unethical. Despite such reservations, innovative surgeons showed that heart wounds could be successfully repaired. Then, extracardiac procedures were performed to correct patent ductus arteriosus, coarctation of the aorta, and tetralogy of Fallot. Direct surgery on the heart was accomplished with closed commissurotomy for mitral stenosis. The introduction of the heart-lung machine and cardiopulmonary bypass enabled the surgical treatment of other congenital and acquired heart diseases. Advances in aortic surgery paralleled these successes. The development of coronary artery bypass grafting greatly aided the treatment of coronary heart disease. Cardiac transplantation, attempts to use the total artificial heart, and the application of ventricular assist devices have brought us to the present day.

Although progress in the field of cardiovascular surgery appears to have slowed when compared with the halcyon times of the past, substantial challenges still face cardiac surgeons. It can only be hoped that sufficient resources and incentive can carry the triumphs of the 20th century into the 21st. This review covers past developments and future opportunities in cardiac surgery.

After a slow start and resistant attitudes, progress in cardiac and cardiovascular surgery was remarkably rapid during the 20th century. Herein, the major advances in surgical techniques and technology are reviewed, and future goals and challenges are discussed.

Early Resistance to the Idea of Performing Cardiac Surgery

Given the wide variety and effectiveness of cardiovascular surgical techniques that are now routinely used, it is remarkable how, during the late 19th and early 20th centuries, the surgical treatment of heart disease was considered to be outside the limits of propriety and acceptability. The innovative Theodor Billroth cast a wary eye on any such attempts in his time. Although his disapproval did not appear in any of his published work, at a meeting of the Vienna Medical Society in 1881 he reportedly muttered, “No surgeon who wished to preserve the respect of his colleagues would ever attempt to suture a wound of the heart.”¹

If even emergent efforts to save lives were looked upon with disfavor, surgery to correct existing cardiac conditions was viewed with far greater hostility. The belief that the heart was beyond the limits of surgical practice resulted in a dearth of such work in the field. In a popular book that was published in 1957, The Century of the Surgeon, by Jürgen Thorwald,² not one mention of cardiac surgery appears. Furthermore, in a more comprehensive review of surgery's progress, published in 1978, the topic of vascular surgery occupies only 19 of 782 pages.³ More recently, books dedicated to the history of cardiac surgery have appeared, calling attention to the period in which cardiovascular surgery began to flourish.^4–6 Broad and deep evolution has occurred in this medical field.

The early misgivings of many gave way to medical necessity as dramatic attempts were made to save victims of stabbings and other types of cardiac trauma. In 1891, Henry C. Dalton in St. Louis was the first surgeon to repair a pericardial wound in a human being. A similar success was achieved by Daniel Hale Williams in Chicago, in 1893. In 1906, Ludwig Rehn of Frankfurt compiled a summary of 124 cases of cardiac-wound repair that had been performed in Europe during the 1890s and thereafter. The survival rate of 40% was remarkable for that period.

Extracardiac Procedures and Beyond

The performance of extracardiac procedures began with the ligation of a persistent patent ductus arteriosus by Robert E. Gross in 1938.⁷ During the 1940s came Clarence Crafoord's repair of aortic coarctation⁸ and the Blalock-Taussig procedure for relieving the effects of hypoxia and polycythemia in the cyanotic congenital condition called tetralogy of Fallot.⁹ Russell C. Brock in England relieved pulmonic stenosis in 3 patients who had tetralogy of Fallot, reducing the right-to-left intracardiac shunting.¹⁰ Although full repair of this congenital defect would have to await the introduction of open-heart surgery, these initial procedures relieved symptoms and extended the lives of thousands of affected infants and children. Many would undergo full repair in later life.

Another noteworthy extracardiac procedure involved Charles Hufnagel's ball-and-cage device, which was inserted into the descending aorta in patients with severe aortic regurgitation.¹¹ Regurgitation was reportedly reduced by as much as 70%. This device was a precursor of mechanical valves that were developed after cardiopulmonary bypass (CPB) was introduced. Yet another important procedure that gained acceptance during the first half of the 20th century was pericardiectomy for patients with constrictive pericarditis.⁴

The first direct surgical repair of a common, chronic structural abnormality of the heart was mitral commissurotomy for mitral stenosis. The path leading to this achievement was long and arduous.¹² This mechanical solution for the treatment of mitral stenosis—first suggested by Sir T. Lauder Brunton in 1902—was resisted for years by authorities such as Sir James Mackenzie and Sir Thomas Lewis, neither of whom acknowledged a correlation between the extent of valvular obstruction and progress of the disease. They and their adherents thought that the problem lay in the diseased myocardium rather than in the valvular obstruction.

In Boston in 1923, Elliot Carr Cutler and Samuel A. Levine reported the successful manual opening of a stenotic mitral valve in a 12-year-old girl. In 1925, in England, Henry Souttar achieved a successful long-term outcome in a patient with mitral stenosis and mitral insufficiency. However, Cutler was unable to replicate his success in subsequent patients, and Souttar's colleagues did not permit him to perform the procedure again. No one else reported beneficial results. Accordingly, the procedure was abandoned until the mid-1940s.

From 1945 through 1948, operative successes with closed mitral commissurotomy were achieved by Charles P. Bailey in Philadelphia; Dwight E. Harken in Boston; Horace G. Smithy in Charleston, South Carolina; and Russell Brock in London. However, closed commissurotomy was not always an optimal procedure. In some patients, the mitral valve was too calcified to permit dilation; immoderate enlargement of the mitral orifice might convert mitral stenosis into severe mitral regurgitation; and patients in whom mitral regurgitation was the chief problem were not candidates for the procedure. In addition, patients who had concomitant disorders of the aortic valve could not benefit from closed-heart surgery.

When open-heart surgery was introduced, a great many more cardiac conditions could be treated. Albert Starr's placement of a ball valve in the mitral position was a first step.¹³ Dwight Harken subsequently inserted the first mechanical prosthesis in the aortic position.¹⁴ Later came heterografts, championed most effectively by Alain Carpentier in France.¹⁵ Numerous other valves of various designs were also developed.

In the years before CPB, surgical investigators did not limit themselves to treating mitral stenosis; they devised other procedures to treat various lesions. For example, innovations were made in the excision of ventricular aneurysms and the closure of atrial septal defects (ASDs). Wilfred Bigelow of Canada proposed one of the most ambitious endeavors: the use of hypothermia during open-heart repairs. In 1952, F. John Lewis and his colleagues at the University of Minnesota performed the first successful repair of an ASD with the use of hypothermia.¹⁶ Although Lewis retired from investigative surgery not long thereafter, Henry Swan in Denver reported multiple positive outcomes with use of this technique.⁶ Although hypothermia was superseded by CPB machines in open-heart surgery, the lowering of patients' body temperatures has remained part of the technique.

An equally innovative approach to the performance of open-heart surgery in the pre-pump days was conceived by C. Walton Lillehei at the University of Minnesota: controlled cross-circulation using adults (usually parents of children undergoing surgery) as stand-ins for pump oxygenators. From 1954 through 1955, Lillehei and his colleagues performed 45 of these procedures, mainly in the repair of ventricular septal defects. Outcomes were excellent even at 30 years after operation.¹⁷

The Introduction of Cardiopulmonary Bypass

In 1953, after many years of effort, John Gibbon performed the first open-heart procedure with use of the heart-lung machine that he had developed, closing an ASD.¹⁸ However, he was unable to reproduce this result in several subsequent patients, and he abandoned further attempts. Using a modification of the Gibbon apparatus, John Kirklin at the Mayo Clinic performed the first series of such procedures.¹⁹ Although the series was small (8 patients) and the mortality rate was high by current standards (50%), the attempt was favorably viewed, and it encouraged surgeons to persist in similar efforts. Meanwhile, at the University of Minnesota, Richard DeWall developed a simpler pump, a disposable bubble oxygenator, that was clinically effective and greatly increased surgical facility.²⁰ Cardiac surgeons could now correct a variety of cardiac conditions under direct vision, and important advances were also occurring in the treatment of aortic aneurysms and dissections. Leaders in this work were Michael E. DeBakey and Denton A. Cooley in Houston.^21,22

The Challenge of Coronary Heart Disease

As the backlog of patients with congenital heart disease was dealt with, and the demand for valvular heart surgery declined along with rheumatic fever and rheumatic heart disease in the industrialized world, a different challenge arose. This was coronary disease, which seemed to develop into what has been described as an epidemic in the post-World War II years.

The idea of surgically relieving coronary obstruction was not new. It had been proposed as early as 1913 by Alexis Carrel, who had performed coronary bypass surgery in a dog with use of a carotid artery segment as a bridge between the aorta and left coronary artery. Within the confines of clinical practice, more modest techniques (often of questionable efficacy) were offered for the relief of myocardial ischemia. In the 1930s, Claude Beck attempted to increase collateral blood flow to ischemic areas by attaching a muscle pedicle to the surface of the heart.²³ In 1951, the Canadian surgeon Arthur Vineberg threaded internal mammary arterial branches into ischemic regions.²⁴ Although collateral blood flow could eventually be shown on angiography, the time lag of several months for this to develop was often too long to deal with the effects of imminent coronary occlusions. A more direct attack on coronary obstructions was endarterectomy, introduced by Charles Bailey, William P. Longmire, and their respective associates.^25,26

Coronary Artery Bypass Grafting

Coronary artery bypass grafting (CABG) involved the implantation of venous segments or an internal mammary artery directly from the aorta to a point beyond existing obstructions. Guided by selective coronary angiography as introduced by Mason Sones at the Cleveland Clinic, CABG would become the procedure of choice; however, this did not occur overnight.²⁷ The idea of CABG was doubted and resisted in conservative medical circles even into the late 1960s.

In 1960, Robert Hans Goetz performed the first successful coronary bypass operation, grafting the right internal mammary artery to the right coronary artery. His medical and surgical colleagues vehemently criticized the procedure, which they considered to be unwarranted and highly experimental,²⁸ and Goetz never performed CABG again. In 1962, David Sabiston performed a saphenous bypass procedure in a patient who died 3 days later of cerebral complications; this case was not reported until 1974. In 1964, after an unsuccessful attempt at coronary endarterectomy, H. Edward Garrett and colleagues performed the first successful CABG with use of the saphenous vein in a human being. Seven years later, angiography showed that the graft was patent. This case was not reported until 1973.

In Soviet Russia, Vasilii I. Kolesov in Leningrad was undertaking pioneering work. He performed his first successful CABG in 1964 and continued this work in his clinic for years. During much of this time, his was the only program in the world in which this surgery was routinely performed.⁶ René Favaloro, working closely with Mason Sones in Cleveland, used the saphenous vein for grafting and thus fueled the popularity of CABG for the relief of coronary obstruction.^29,30 Today, CABG remains one of the most frequently performed surgical procedures in the world.

Cardiac Transplantation

The world was enthralled by the report from South Africa's Groote Schuur Hospital on 3 December 1967 that Christiaan Barnard had performed the first human-to-human cardiac transplantation.³¹ As with CABG, this achievement was possible by virtue of knowledge gained from numerous past experimental studies.^32,33 Alexis Carrel and Charles C. Guthrie (1905), Frank C. Mann (1933), Emanuel Marcus and Aldo A. Luisada (1951), W.G. Downie (1953), and Vladimir Demikhov (1956) had all laid the groundwork for Barnard's success. In 1960, Richard R. Lower and Norman E. Shumway had devised the basic technique to be used in this surgery.³⁴ In 1964, James D. Hardy at the University of Mississippi had transplanted a chimpanzee's heart into a dying man. On the eve of Barnard's operation, Adrian Kantrowitz at Maimonides Hospital in Brooklyn was planning to transplant the normal hearts of anencephalic babies, soon doomed to die, into other infants who had severe congenital heart defects. He had perfected the technique by experimenting on more than 400 puppies.

The initial enthusiasm for cardiac transplantation, especially after the relatively long 19-month survival of Barnard's second patient, the dentist Philip Blaiberg, encouraged surgeons around the world to embark on programs of cardiac transplantation for patients in refractory heart failure. However, other patients were not as immunologically fortunate as Blaiberg, and the early rejection of transplanted hearts was a seemingly insurmountable obstacle. The introduction of cyclosporine in the 1970s greatly extended the survival of transplantation patients, but another problem became apparent: far too few donor hearts were available for so many operative candidates. This discrepancy has persisted. In recent decades, only 2,000 or so transplantations have been performed each year in the United States, despite many more thousands of patients in need.

The Development of Mechanical Support

This chronic shortage of donor hearts impelled a search for mechanical support to serve as a bridge to transplantation or as permanent treatment in itself.⁴ The first clinical application of a total artificial heart took place in 1969, when Denton Cooley used the unit devised mainly by Domingo Liotta as a bridge to transplantation. Cooley and colleagues made a second attempt in 1981. However, both patients died soon after transplantation. In 1984, a total artificial heart was permanently implanted in a human patient by William DeVries, Willem S. Kolff, and Robert K. Jarvik and colleagues at the University of Utah in Salt Lake City.³⁵ The patient, Barney Clark, experienced multiple and predominantly thromboembolic sequelae and died after 112 days of a difficult postoperative course. Later attempts by DeVries yielded no clear improvement in outcomes. For the present, total artificial hearts have given way to the use of left ventricular assist devices. Pulsatile-displacement and the more recent continuous axial-flow models appear to offer a relatively good quality of life for some period of time. Many of these devices are undergoing long-term evaluation.^36,37

What Remains to Be Done?

Increasing numbers of patients have end-stage heart failure that is unresponsive to medical therapy. Approximately 5 million persons in the United States are currently affected, and half a million additional cases are diagnosed each year. Current surgical research involves the continuing evaluation of different left and right ventricular assist devices and the development of improved designs. Although the potential use of total artificial hearts has diminished in comparative priority, future models may overcome the deficiencies of their precursors.

As the struggle to improve upon the mechanics of existing cardiac-support devices continues, new possibilities are being explored regarding transplantation in the treatment of end-stage heart failure. The shortage of human donor hearts has focused investigative attention on xenotransplantation research, which has quietly progressed in several laboratories over the past 2 decades. By genetically altering donor organs—for example, from the pig, so that transplanted porcine organs do not elicit a rejection response in a human recipient—surgeons might one day achieve cardiac transplantation from pigs to human beings.³⁸

In our aging population, calcific aortic stenosis is a major health concern. It has been estimated that, in the U.S., between 2% and 4% of individuals aged 65 years or older will develop this disease. This number climbs to approximately 8% in persons 85 years and older. Many of these patients have coexisting aortic abnormalities, renal insufficiency, multiorgan dysfunction, or extensive vascular disease³⁹ that precludes traditional valve replacement with the use of CPB. Percutaneous transcatheter aortic valve implantation, introduced by Cribier and colleagues⁴⁰ and pursued by others,⁴¹ offers new hope for these patients.

In conventional valve replacement, the search continues for an ideal prosthetic valve, one that incorporates the longevity of a mechanical prosthesis and the safety of a bioprosthesis without the need for anticoagulation.

Congenital heart defects such as hypoplastic left heart and complete transposition of the great vessels continue to present operative challenges to the cardiothoracic surgeon. Moreover, outcomes from the use of endovascular devices in the treatment of aortic and carotid diseases require continued prospective study in comparison with established surgical treatments.

Will Surgical Manpower Be Sufficient to Achieve These Goals?

After C.W. Lillehei's first successes with open-heart surgery in Minnesota, Denton Cooley remarked that Lillehei had provided “a can opener to the biggest picnic cardiac surgeons had ever known.” Could it be that the “party” is coming to an end? Ironically, progress may be the cause.

In 1979, Andreas Gruentzig introduced percutaneous coronary angioplasty, which has almost universally become the procedure of choice (along with stent implantation) in relieving coronary obstructions. Interventional cardiology is encroaching upon cardiovascular surgery. Fewer CABG procedures are performed in surgical practice, and this has had profound consequences: without this major source of income, a career in cardiovascular surgery has become unsustainable for many. The attraction of new recruits to the field has diminished substantially. In 2006, Edward B. Diethrich pointed out the declining numbers of applicants for cardiovascular surgical fellowships.⁴² In 2007, there were only 100 applicants for 132 fellowship positions. In 2010, only 103 applied for 113 positions, and, of these, only 88 were filled.⁴³ Diethrich noted that graduates of these programs are increasingly unable to find employment. This was shocking news to those of us who had witnessed cardiovascular surgery at its zenith, when surgical fellowships were highly competitive and hotly pursued. Then, the graduates of such programs could look forward to a bright and productive future.

While we all may bask in the afterglow of the tremendous advances in 20th-century cardiac surgery, we can only hope that in the 21st century we will be able to witness additions to this splendid record.

Acknowledgment

Dr. David K.C. Cooper kindly reviewed this paper before its submission.