Cardiothoracic surgery and invasive/interventional cardiology have historically grown and developed together with each discipline complementing the other. The changes seen in both disciplines over the last decade, particularly the advent of percutaneous valve technology, have led some to speculate on the demise of cardiothoracic surgery. Such claims are not merely exaggerated but, frankly, wrong. Looking back at the history of both disciplines helps elucidate the depth of the connection between the two and helps contextualize the recent technological changes. The existence of a complementary relationship between the two disciplines has always proven beneficial not only to the practitioners in each field but, most importantly, to patients.

In 1958, F. Mason Sones at the Cleveland Clinic inadvertently discovered coronary angiography. While studying a young man with rheumatic heart disease, Sones placed a catheter in the aorta with the intention of performing an aortogram. The catheter, however, accidentally engaged the right coronary artery, and a fortuitous coronary angiogram was performed. Recognizing this happy accident as an opportunity to delineate coronary artery anatomy and coronary artery disease, Sones went on to study video engineering, X-ray physics, contrast dye chemistry, and optics to develop the modern art of coronary angiography. Several years later in 1967, Sones's cardiothoracic surgery colleague at the Cleveland Clinic, René Favaloro, performed the first coronary artery bypass graft (CABG) surgery. Without Sones's invention, Favaloro's life-saving procedure would not have been possible. From the beginning, the growth and development of one discipline has complemented the growth and development of the other.

The next two decades saw the widespread adoption of bypass as the gold standard for the treatment of coronary artery disease. In the meantime, Andreas Gruentzig performed the first successful catheter-based coronary balloon angioplasty procedure in 1977. That event marked the birth of the field of interventional cardiology. Catheter-based therapies revolutionized the management of acute coronary syndromes and resulted in the widespread adoption of percutaneous coronary intervention (PCI) over the next several decades. The rapid expansion of percutaneous treatment options for coronary disease did not, however, eliminate bypass surgery. While percutaneous intervention has shown mortality benefit in settings such as acute myocardial infarction, bypass has always proven superior from a mortality standpoint in the setting of stable multivessel or left main disease, particularly among patients with diabetes.¹ Each discipline has, thus, found a space to serve patients, each being complementary of the other.

By the mid-to-late late 2000s, in fact, the concept of a team approach to the treatment of coronary disease began to take hold. In an article published in 2009, a group from Vanderbilt reported the feasibility and safety of a hybrid strategy in which patients underwent combined bypass/PCI procedures with all patients receiving completion angiograms at the conclusion of their hybrid revascularization procedure. The group concluded that the combination of tools from both the catheterization lab and the operating room enhances the options available to the cardiothoracic surgeon and the interventional cardiologist and, therefore, improves their ability to care for patients with complex coronary artery disease. To quote their conclusion, "Our data suggest that routine completion graft imaging should eventually become the standard of care in CABG surgery. Furthermore, with the increased complexity of patients referred for cardiac surgery, a team approach, combining traditional cardiac surgical techniques and PCI, may be beneficial, especially in high-risk populations."² The theme underlying this hybrid approach was to put the personal interests of the individual practitioner aside and focus instead on the best approach for the patient.

The next step in this transformation was the Placement of Aortic Transcatheter Valves (PARTNER) trial. The advent of catheter-based therapies for aortic valve replacement further solidified the concept of a team approach to complex patient care. While open heart surgery has long been the gold standard for the treatment of severe aortic stenosis, 30-40% of patients with this condition could not be offered open surgical aortic valve replacement because of prohibitive surgical risk. To quote the original PARTNER trial, "In clinical practice, at least 30% of patients with severe symptomatic aortic stenosis do not undergo surgery for replacement of the aortic valve, owing to advanced age, left ventricular dysfunction, or the presence of multiple co-exiting conditions. For these patients, who are at high surgical risk, a less invasive treatment may be a worthwhile alternative."³

Identifying which patients were truly at excessive risk with open surgical valve replacement depended on the Society of Thoracic Surgery (STS) risk score as well as the determination by two or more of the surgical investigators that a given patient faced a 15% or greater risk of mortality with open aortic valve replacement or a greater than 50% risk of morbidity with open aortic valve replacement. As a matter of practical application, these decisions became the substance of discussion at organized "valve conferences" where the entire heart valve team would consider the candidacy of any given patient for valve replacement. This approach has allowed cardiothoracic surgeons and interventional cardiologists to evaluate patients together in multidisciplinary "valve clinics" and openly discuss the risks of benefits of surgical versus transcatheter valve replacement in organized multidisciplinary valve conferences. The maturation of the heart team and valve conference concepts has allowed for a growth of valvular and structural heart disease referral centers that have seen the explosive growth of both transcatheter and surgical procedures.

Thus, the dawn of transcatheter valve technology has by no means reduced the role or importance of cardiothoracic surgeons. Given the historical growth and development of both disciplines, the adoption of transcatheter techniques in which both cardiothoracic surgeons and interventional cardiologists participate in all aspects of valvular heart disease management and care confirms the historic paradigm whereby both disciplines benefit by growth and development of the other.

The future is a world in which cardiothoracic surgeons and interventional cardiologists scrub cases together, with cardiothoracic surgeons mastering the wire and catheter skills of the endovascular world, and interventional cardiologists acquiring the basic cut-down skills of the surgical world. As a result of the cross breeding of the two disciplines, each will be able to take the techniques learned from the other back to their respective arenas. Cardiothoracic surgeons will use more endovascular techniques and interventional cardiologists will employ more surgical techniques in their respective procedures. Regardless of who performs which procedure, the closer the working relationship between the two disciplines, with a focus on what is best for patients rather than what is best for the practitioners, the better the potential outcomes for patients will be. The needle and the knife will always need one another. The better their collaboration, the better served cardiac patients will be.

References

1. Serruys PW, Morice MC, Kappetein AP, et al. Percutaneous coronary intervention versus coronary-artery bypass grafting for severe coronary artery disease. N Engl J Med 2009;360:961-72.
2. Zhao DX, Leacche M, Balaguer JM, et al. Routine intraoperative completion angiography after coronary artery bypass grafting and 1-stop hybrid revascularization: results from a fully integrated hybrid catheterization laboratory/operating room. J Am Coll Cardiol 2009;53:232-41.
3. Leon MB, Smith CR, Mack M, et al. Transcatheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery. N Engl J Med 2010;363:1597-607.

Keywords: Accidents, Acute Coronary Syndrome, Angioplasty, Balloon, Coronary, Aorta, Aortic Valve, Aortic Valve Stenosis, Breeding, Cardiac Surgical Procedures, Catheterization, Cooperative Behavior, Coronary Angiography, Coronary Artery Bypass, Coronary Artery Disease, Coronary Disease, Diabetes Mellitus, Growth and Development, Heart Valve Diseases, Humans, Intention, Inventions, Male, Myocardial Infarction, Needles, Operating Rooms, Patient Care, Physics, Prednisone, Referral and Consultation, Research Personnel, Rheumatic Heart Disease, Standard of Care, Surgeons, Surgical Instruments, Thoracic Surgery, Ventricular Dysfunction, Left, X-Rays

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