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Ann Thorac Surg 2006;81:10-18
© 2006 The Society of Thoracic Surgeons

Presidential address

The Impact of New Technology on Cardiothoracic Surgical Practice

D. Glenn Pennington, MD *

Division of Cardiovascular and Thoracic Surgery, Department of Surgery, East Tennessee State University, Johnson City, Tennessee

* Address correspondence to Dr Pennington, Division of Cardiovascular and Thoracic Surgery, Department of Surgery, East Tennessee State University, P.O. Box 70575, Johnson City, TN 37614-0575 (Email: penningg{at}etsu.edu).


   Introduction
Top
 Introduction
Coronary Bypass Grafting
 Heart Failure
 Valvular Surgery
 Congenital Heart Surgery
 General Thoracic Surgery
 Footnotes
 References
 
My choice of this topic of new surgical technology stems not only from the thoracic surgeon's inherent attraction and even affection for new techniques, instruments, devices, and gadgets and the potential benefits such technology may offer our patients, but the impact that rapidly changing technology may have on us as thoracic surgeons and as individuals. Perhaps more than ever before, we find ourselves faced with choices between the established, well proven, comfortable technology requiring no new training and the possibly more effective new technology which requires significant effort to learn and adapt to our practices. Not only are there varying degrees of stress created by the need to learn the new techniques, there are ethical, moral, and legal concerns accompanying the introduction of new techniques and procedures. For example, is it necessary to extensively retrain ourselves and our teams in order to make a smaller, perhaps less painful incision for a procedure we've done well for many years through a larger incision? The answer is "yes", if we can show the benefit to our patients without compromising quality. Fogarty warns us that the pace and rate of technologic change has increased to the point that an established procedure begins a challenge of obsolescence in seven years [1].

A corollary of the thoracic surgical challenges of change has recently developed in the automobile industry, a favorite and frequent fascination of Americans, particularly surgeons. The Oldsmobile was recently declared dead! Gone is the magic and thrill of one of America's most beloved performers as a family car as well as a racing car. Founded in 1897, Oldsmobile developed the famous "Rocket 88", a V-8 gasoline engine, which led to its recognition as a real "muscle car". Oldsmobile was the first to employ true assembly line technology, the first to use chrome trim, the first to mass produce a fully automatic transmission, the "hydramatic", and the first in the U.S. to build a car with front wheel drive, the Toronado. In spite of these impressive advances, in the end the Oldsmobile engine was not fuel efficient and its emissions contributed significantly to air pollution, making it easy prey to the increasing demand for sport utility vehicles and better technology and leading to its ultimate demise. In contrast, the Toyota Prius with a hybrid gasoline/electrical engine, achieves 45–50 miles per gallon and markedly reduces air pollution. Even though it was marketed in early 2000, it languished on dealer's lots with few buyers for several years. Recently, this obviously superior technology was brought to the forefront by sharp increases in oil prices and the sudden interest in it by Hollywood stars. The Prius was catapulted to the position of the most sought-after car in America with long waiting lines and plans by others in the automobile industry to create new hybrids, including sport utility vehicles.) It is clear that we must now give up our Oldsmobiles, but is it inevitable that we become Prius owners? Perhaps we should wait until hydrogen-fueled automobiles are perfected?


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Similar questions are being asked by cardiothoracic surgeons who are confronted and perhaps intimidated by the large array of technological developments occurring in our specialty today. It is my hope that a brief but systematic review of some of these developments will add to our understanding of them and help us to formulate plans for their appropriate rejection or inclusion and incorporation into our practices.


   Coronary Bypass Grafting
Top
 Introduction
 Coronary Bypass Grafting
Heart Failure
 Valvular Surgery
 Congenital Heart Surgery
 General Thoracic Surgery
 Footnotes
 References
 
Some of the most important changes are occurring in coronary arterial bypass grafting (CABG), triggered by the vigorous pursuit in many major centers of off-pump coronary artery bypass grafting (OPCAB). These changes were prompted in part by the sharp increase in competition from cardiologists performing percutaneous intervention (PCI) for coronary revascularization. From 1990 to 2001, the number of PCI's increased 86%, while CABG increased only 15% [2]. The recent introduction of drug-eluting stents will further influence referral patterns away from surgical revascularization [3]. The progression of less invasive CABG technology now includes OPCAB, minimally invasive CABG (MIDCAB), and totally endoscopic (TECAB) techniques, which employ thoracoscopic and robotic technology. Current most commonly performed OPCAB procedures include a full sternotomy, complete revascularization performed off-pump, often including at least two arterial grafts and sometimes avoiding aortic clamping. Arterial grafts and proximal anastomotic connectors make it more feasible to avoid aortic cross clamping, even partial aortic clamping. Significant questions have arisen regarding the benefits of OPCAB, and these controversies seem to have limited the wider application of OPCAB techniques. However, a recent extensive review by CTS Net editors of over 1200 peer-reviewed publications concluded that OPCAB is being performed in hundreds of centers across the world, that complete and arterial revascularization are possible, that it reduces early mortality and some morbidity of on-pump CABG, including cognitive dysfunction, stroke and renal failure [4]. These findings are supported by a recent comparison of on and off-pump CABG in more than 17,000 patients with multi-vessel disease from four institutions with extensive experience in OPCAB surgery [5]. Individual centers have shown economic advantages [6]. While the optimal performance of OPCAB mandates a rigorous re-engineering of the surgical production process, including a rather steep learning curve for the surgeon, OPCAB is clearly here to stay [4].

The MIDCAB procedures are performed primarily to avoid the discomfort of sternotomoy and in redo procedures to avoid injury to the heart or conduits. Recent reports by Subramanian [7] and Newman [8] describe techniques for subclavian, anterior, lateral and transabdominal (subxyphoid) MIDCAB approaches. These involve thoracoscopic or robotic internal mammary harvest, endoscopic radial artery and saphenous vein harvest, and use of the gastroepiploic artery for transabdominal MIDCAB. These approaches represent significant challenges to even the accomplished OPCAB surgeon who usually employs full sternotomy, but can be mastered by stepwise incorporation of these techniques. For example, addition of thoracoscopic or robotic IMA harvest can be introduced with full sternotomy exposure initially, followed by progression to thoracoscopic MIDCAB. The use of multiple arterial grafts and proximal aortic connectors greatly reduce the need for ascending aortic clamping. The surgeon is further aided in the retraining process by a wide array of retractors and stabilizing devices, particularly the use of endo-stabilizers which allow insertion through small ports remote from the MIDCAB incision. Both internal mammary arteries can be harvested endoscopically through three ports on the left anterior chest [7].

Totally endoscopic CABG (TECAB) requires another magnitude of expertise, but has the obvious advantage of minimal incisions. Until the perfection of distal anastomotic devices, the distal anastomoses can be performed on the arrested heart using remote access perfusion and aortic endo-occlusion [9, 10]. Because of the limitation of lack of specific stabilizers, difficulty identifying appropriate anastomotic sites, and the lack of distal anastomotic devices, TECAB has been successfully performed in less than a dozen centers in the world [11]. It is clear that well planned progressive application of these techniques by accomplished OPCAB and MIDCAB surgeons will be required for success in the short term [12], but the development of effective distal anastomotic connectors will greatly speed the wider application of this technology.

What are the current and anticipated future surgeons' responses to these exciting techniques? It is somewhat surprising to note that only about 15% of CABG's were performed using OPCAB techniques in 2003, but that number is expected to more than double by 2008 [3]. I believe that as OPCAB surgery increases, MIDCAB surgery will become more attractive, particularly in redo CABG cases. Surgeons will then be more likely to adopt thoracoscopic internal mammary harvest, which can then be performed robotically. It appears that the widespread use of robotic TECAB will not occur until reliable and effective distal anastomotic devices are available. Robotic techniques will not have widespread use in the next few years because of the expense of robotic equipment and the steep learning curve required to perfect those techniques [12]. In centers where robotic TECAB is performed, careful patient selection will be important.

Atrial fibrillation (AF) represents a major epidemiological problem in the U.S., occurring in 1% of the population, increasing with age, and costing more than 16 billion dollars per year. Drugs and cardioversion cure only about 30% of patients and until recently, cardiac surgeons had virtually no role in its treatment. Recently, pioneer James Cox [13] delineated the two major types of atrial fibrillation as paroxysmal AF and chronic AF, based upon the anatomic pathology and pathophysiology of the two types. Forty percent of patients have paroxysmal AF which arises from ectopic foci in anatomically normal pulmonary veins and is self-initiating and self-terminating [14]. Sixty percent of patients have chronic AF characterized by no ectopic foci, random macro-reentry circuits with very short cycle lengths resulting in a remodeled atrial action potential in which case "AF begets AF" [15]. Surgery for paroxysmal AF involves isolation of the pulmonary veins, therefore isolating the ectopic foci. This surgery should be performed concomitantly when other surgical procedures are needed, but can be accomplished with minimally invasive techniques as sole therapy. In chronic AF, there are no ectopic foci to ablate or isolate, so a more extensive lesion set is necessary, and minimally invasive techniques are not yet available. The single most effective curative procedure for AF is the CoxMaze III procedure, but it has rarely been performed because of its complexity. A plethora of new devices are in various stages of development, including new energy sources such as radiofrequency, microwave, laser, ultrasound and cryotherapy. It is beyond the scope of this treatise to explore the various characteristics of each of these, but it is important to note how this work dramatically impacts our approach to patients with AF. It now appears that virtually every patient with atrial fibrillation coming to the operating room for other types of cardiac surgery should undergo an ablation procedure as well [16]. The ablation can be performed during cardiopulmonary bypass and cardiac arrest when that is required for the concomitant surgery, but can be done off pump if OPCAB is to be performed. The surgical treatment of lone AF is more of a challenge, because in order for surgeons to compete effectively for these cases, we must avoid sternotomy and use either port access cardiopulmonary bypass or preferably perform the procedures off pump with thoracoscopic techniques [17]. While cardiac surgeons are not likely to increase their volume of cases by performing concomitant surgery, the lone AF procedures could dramatically increase volumes. If only 10% of the 2.5 million people with AF become surgical candidates, an additional 250,000 cases could be performed. Analysis of these cases by the Cardiovascular Roundtable projects an increase during the period from 2003 to 2008 of 15,000 modified maze procedures and 8,000 minimally invasive maze procedures (Fig 1) [18]. It seems clear that many cardiac surgeons who have never performed the traditional CoxMaze procedure will be performing concomitant and even lone therapy modified maze and minimally invasive maze procedures. It is quite possible that cardiac surgeons will significantly impact the epidemiology of atrial fibrillation during the next five years.



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  		Fig 1. Projection of cardiac surgical procedures (modified from Projection of Cardiac Surgical Procedures. Cardiovascular Roundtable Analysis, 2003 National Membership Meeting, page 253).

 

   Heart Failure
Top
 Introduction
 Coronary Bypass Grafting
 Heart Failure
Valvular Surgery
 Congenital Heart Surgery
 General Thoracic Surgery
 Footnotes
 References
 
Heart failure continues to be an enormous burden for health care resources in the United States. Five million patients have congestive heart failure with 500,000 new cases diagnosed annually. With current therapy, the one year mortality ranges from 10 to 70%, one-third die suddenly and heart failure patients account for 1.7 million hospital discharges per year. Total cost for treating heart failure in the U.S. in 2003 was a staggering 28.8 billion dollars! Conventional procedures to correct valvular, coronary arterial, and congenital defects are of limited or no value for many of the more advanced heart failure cases. Heart transplantation, pacemaker/defibrillaters and mechanical circulatory support devices have also played a role in controlling this huge epidemiological problem. However, it is projected that there will be substantial penetration of device-based therapies for the U.S. heart failure population from 2004–2008. These new therapies include surgical ventricular restoration (SVR) procedures, ventricular restraint devices, mechanical circulatory support devices including ventricular assist devices (VADs) and ventricular replacement devices (TAHs), and cellular implantation into the impaired myocardium.

Surgical ventricular restoration procedures include a variety of techniques with overlapping components but can generally be described as the Cooley endoventricular repair, the Dor endoventricular circular patch plasty, the Mickleborough modified linear closure, the Jatene circular patch restoration and the McCarthy procedure utilizing concentric purse-strings and overlaying linear closure. The goals of these procedures are primarily to reduce the volume and thereby the stress in the left ventricle, to restore the elliptical shape, re-orient the papillary muscles, define a new apex, and correct mitral insufficiency. Elliptical shaped balloons (Chase Medical, Richardson, TX) have been used as mannequins to guide the procedures and a special prosthetic patch (Somanetics Corp, Troy, MI) has been designed to facilitate the ventricular repair. Pre and post-operative measurements of left ventricular systolic volume index (LVESVI) show substantial reductions. The RESTORE Surgical Group, consisting of fourteen U.S. and international centers, have demonstrated the effectiveness of low operative risk, improved left ventricular ejection fraction (LVEF), decreased LVESI, high survival at three-years, low admission rates for congestive heart failure and improvement to New York Heart Association Class I and II after operation [19, 20, 21]. The value of the SVR procedures will be determined as a subcategory of the currently ongoing STICH (Surgical Treatment for Ischemic Heart Failure) trial in which SVR, CABG, and medical therapy will be compared [22]. If SVR proves beneficial in these studies, much wider application of these procedures by cardiac surgeons is anticipated. It is currently anticipated that these procedures may generate about 1500 new cases over the next four years [18].

Another approach to ventricular restoration is by external compression devices. The CorCap (Acorn Cardiovascular, St. Paul, MN) external compression device has been shown to decrease ventricular volume and has been applied in more than 300 patients. The myosplint (Myocor, Maple Grove, MN) device applies discrete linear constriction which reduces the radius of the left ventricle, thereby reducing left ventricular stress. This device has also had limited clinical application in feasibility trials in Europe and the United States. Two other devices, the Paracor (Paracor Medical, Sunnyvale, CA) external net device which has the potential for thoracoscopic insertion and the Cardioenergetics (Cardioenergetics, Cincinnati, OH) device, which also applies discrete external compression, have not been used clinically. The impact of these devices on the surgical treatment of heart failure is not clear, but estimates are that 6000 new cases will be performed with these devices by 2008 [18].

Mechanical circulatory support devices have been used successfully for heart failure in three clinical settings: bridge to recovery, bridge to transplantation, and as "destination therapy" for patients who are not transplant candidates. This technology has long been a fertile field open to the imagination and genius of thoracic surgeons, engineers, gadgeteers, entrepreneurs, and others who often began with meager resources but have subsequently developed a modest but growing industry. Recently this entire field reached an important landmark by successful demonstration in the REMATCH trial [23] that ventricular assist device (VAD) support provided better survival than optimal medical management for a group of the sickest patients who were ever entered into a clinical heart failure trial. From that experience, the Centers for Medicare and Medicaid Services (CMS) approved reimbursement for long-term VAD destination therapy. While the REMATCH trial utilized the Thoratec Heart Mate I VAD (Thoratec Corp, Pleasanton, CA), which has been in clinical use for more than 20 years, the device underwent numerous modifications during and following the trial so that the current version actually represents new technology. Recently, World Heart Corporation (World Heart Corporation, Oakland, CA) was approved for a trial of destination therapy with the Novacor VAD, which will be randomized in a ratio of 2:1 to the Heartmate I VAD. CMS funding for destination therapy technology was initially limited to transplant centers, but may now include non-transplant centers, making this therapy more available for medicare recipients in centers who have not previously been involved with destination therapy. Centers with destination therapy programs report a significant increase in end stage heart failure referrals and revenue [24].

Two new devices, the Arrow Lionheart VAD (Arrow International, Reading, PA) and the Abiocor (Abiomed Inc, Danvers, MA) total artificial heart (TAH) have achieved the long-sought goal of complete implantability without external drive lines and are currently undergoing clinical trials in the United States. Other established devices are undergoing major changes. The Thoratec VAD (Thoratec Corp) has recently been redesigned to provide an implantable model which is powered by a portable system which will allow discharge from the hospital. Abiomed, Inc. has designed a paracorporal sac-type VAD, the AB 5000, which will allow patients much more mobility than the BVS 5000. The CardioWest TAH has been used with the Berlin Heart Excor driver to allow patients more mobility and the opportunity for hospital discharge [25]. With the addition of these new devices, it is likely that cardiac surgical centers and surgeons who have never employed VAD's or TAH's may wish to incorporate these devices into their heart failure programs.

The devices described above are all displacement blood pumps which provide pusatile flow, but rotary pumps which provide nonpulsatile flow have several advantages including small size, low mass, decreased blood damage, low-noise operation, and lower costs. Examples of axial flow devices currently undergoing clinical trials are the Jarvik 2000 VAD (Jarvik Heart Inc, New York, NY), the DeBakey Micromed VAD (Micromed Technonogy Inc, Houston, TX), and the Thoratec Heartmate II VAD (Thoratec Corporation, Pleasanton, CA). These devices generate physiological levels of flow at high revolutions per minute with minimal hemolysis. Centrifugal pump and magnetic levitation VAD's are also in various stages of development. Current estimates are that approximately thirty rotary blood pumps are in development world-wide. It now seems clear that nonpulsatile flow is compatible with short term survival without significant pathophysiological consequences [26]. The potential disadvantages of rotary blood pumps include monitoring and control problems, lack of valves which poses a risk in case of pump failure, and insufficient long-term experience with non-pulsatile flow.

It now appears that the circulatory support device industry is poised for a marked increase in clinical activity. U. S. News and World Report issued a special health issue on December 1, 2003 entitled "The End of Heart Disease". Ths issue proclaimed that LVAD's have become a real option, the existing LVAD's aren't perfect but there's reason to hope and predicted that LVAD implants will exceed heart transplants by 5–10 fold in five years (> 20,000/year) [27]. Whether this prophecy holds true remains to be seen, but it seems very likely that these devices will be used much more extensively over the next five years.

Another exciting new potential therapy for the damaged myocardium is the use of cellular cardiomyoplasty. A variety of stem cells have been injected into areas of injured myocardium with the hope of invoking myocardial regeneration. Some of the most promising studies involve the transfer of satellite cells (skeletal muscle myoblasts) from adult thigh muscle grown in culture to allow replication and then injected into the same individual's myocardium [28, 29]. The advantage of these autologous cells are the avoidance of embryonic stem cells, the absence of a rejection response to the donor, and the ready availability of the cells. While questions remain about the actual incorporation of these cells into the native myocardium, it is clear that these "regenerated" areas of myocardium can enhance previously diminished myocardial function. The use of angiogenic factors such as vasoendothelial growth factor (VEGF) may be used in combination with cellular cardiomyoplasty [30]. Numerous other cell and protein sources are being investigated.

While not entirely new, the use of transmyocardial laser revascularization (TMLR) in patients with diffuse coronary artery disease has proven to be beneficial in randomized clinical trials [31]. It seems reasonable to inject autologous skeletal myoblasts into the myocardium at the same time to promote regeneration of ischemic or nonviable, but not completely scarred myocardium. Studies in pigs with recent myocardial infarction show that direct injection of autologous skeletal myoblasts into the TMLR channels is effective in providing growth of the cell tranplants with improved myocardial function in the area of the infarction [32]. Currently, the majority of TMLR procedures are performed in conjunction with coronary artery grafting, but if combined with autologous cell transplantation, there may be more value for sole therapy in patients who aren't candidates for CABG, or in patients undergoing mechanical circulatory support who might have time for regeneration of myocardium and weaning of the devices [33]. This field may be enhanced by current attempts to perfect thoracoscopic or robotic techniques for TMLR, which would allow for cell implantation through the device (Cardiogenesis Corporation, Foothills Ranch, CA). Cell-based treatment strategies are just beginning large-scale multi-institutional clinical trials.


   Valvular Surgery
Top
 Introduction
 Coronary Bypass Grafting
 Heart Failure
 Valvular Surgery
Congenital Heart Surgery
 General Thoracic Surgery
 Footnotes
 References
 
Significant advances continue to be made in valvular surgery [34]. Newer applications of some of the established valves for aortic root replacement have been made. The Freestyle stentless valve (Medtronic Inc, Minneapolis, MN) was used successfully to replace complex infected aortic valves [35] and a stentless aortic valve composite graft consisting of the Toronto SPV incorporated in a collagen-coated Dacron tube (St. Jude Medical Inc, Pearland, TX), Intergard, was used for true aneurysm of the ascending aorta with excellent results [36]. It now seems clear that human allograft valves undergo deterioration because of the development of immune responses, elevating HLA antibodies [37]. While it is generally agreed that immunosuppression is not warranted in most allograft recipients, the Synergraft antigen reduction process (Croylife Inc, Kennesaw, GA) for preparing the allograft valves seems to substantially reduce antibody formation in recipients [38]. Despite the excellent promise of the Ross procedure, there is clear evidence of increasing frequency of neoaortic valvular regurgitation and the need for reoperation [39, 40]. If the Synergraft technology proves successful in longer term studies, allograft replacement of the aortic valve may become more attractive than the more technically challenging Ross procedure.

The most radical departure from conventional valve surgery is the concept of applying minimally invasive techniques [41]. The use of small thoracotomy incisions with port access technology and video assisted thoracoscopic surgical techniques have dramatically revolutionized aortic and mitral valve surgery [41, 42]. Current port access techniques include peripheral cannulation, right thoracotomy approach to the mitral valve, valve analysis with standard repair or replacement techniques, cardioplegic arrest for myocardial protection and transesophageal echocardiography. Other important elements include video-assistance with robotic camera stabilization, endoclamp occlusion and delivery of cardioplegia in some patients, transthoracic aortic clamp and ascending aortic cardioplegia cannula in others, and assisted venous return to allow for smaller cannula placement [43]. Conversion to sternotomy was required in only 2.5% of patients in a series of 240 patients undergoing a variety of port access surgical procedures [44].

Yet another step is the use of robotic techniques for mitral valve repair. The DaVinci robotic system (Intuitive Surgical, Sunnyvale, CA) has proved effective in investigative centers. The benefits of robotics in cardiac surgery include smaller incisions, intraoperative articulation allowing the surgeon to suture perpendicular to the shaft, increased flexibility, accurate hand-eye coordination, and instinctive hand movements. There is a magnified high resolution 3D image due to true immersion in the operative site. The surgeon is provided ambidexterity to allow for accurate suture placement with delicate tasks and improved access to the subvalvular structures [44]. The addition of Nitinol clips (Coalescent Surgical, Sunnyvale, CA) has further aided the surgeon by eliminating the need to tie the suture. In major centers with robotic systems available, robotic mitral valve repair seems very achievable, although a significant learning curve is required to master this technology. Obviously, centers who have experience with port access, thoracoscopic, video-assisted mitral valve repair will be well prepared to introduce robotic techniques.

Percutaneous mitral valve repair for mitral insufficiency due to ventricular dilatation is also being vigorously pursued. Coronary sinus rings (Mitralife, Santa Rosa, CA) introduced by catheters encircle the mitral valve and are "cinched" to manipulate the geometry of the annulus. Building on the Alfieri surgical technique, leaflet fasteners perform edge to edge "bow-tie" mitral valve repair using a catheter-delivered leaflet fastener [45]. With this technique, a minimally invasive surgical approach involving a left atrial "purse string" incision and beating heart is also under development. Furthermore, percutaneous valve replacement with stent-mounted valves are being developed and have had clinical applications for the pulmonary [46] and aortic position [47]. It is generally believed that pulmonary valve replacement may be readily accomplished. Aortic valve percutaneous positioning is more complicated because of the heavy calcification in the annulus and the coronary orifices. Paravalvular leakage, tilting of the valve and inadequate fixation have been problematic in experimental development [48]. The challenge for cardiac surgeons is whether these techniques will be forfeited to the interventional cardiologists, or if cardiac surgeons will become directly involved in this technology. If that is to occur, surgeons must become involved now in the early stages of development. It may be that implantation of these devices would be facilitated by minimally invasive cardiopulmonary bypass, or by progression from minimally invasive thoracoscopic valve insertion to full percutaneous techniques, particularly for the aortic position.

Analysts evaluating the future volume of cardiac surgery predict a substantial increase in valvular surgical procedures, particularly mitral valvular repair. Estimates are that valvular surgical cases will increase by about 14% from 2003 to 2008 (Fig 1) [18].


   Congenital Heart Surgery
Top
 Introduction
 Coronary Bypass Grafting
 Heart Failure
 Valvular Surgery
 Congenital Heart Surgery
General Thoracic Surgery
 Footnotes
 References
 
Congenital heart surgery has spawned a host of advanced surgical techniques, many of which have subsequently been incorporated into adult cardiac surgery. However, advanced surgical devices are more often developed for adults and later miniaturized. Often they are delayed in availability to the congenital heart population because of the limited market. Mechanical circulatory support devices for children and infants fell victim to this phenomenon. For years, sophisticated VAD's and TAH's were available only to adults, with extracorporeal membrane oxygenation (ECMO) and adult sized VAD's the primary methods for treating infants and children with cardiogenic shock in the perioperative period as well as in bridging to transplantation. Recently the National Heart, Lung and Blood Institute awarded contracts to five centers to develop VAD's for infants and children. Collectively, these miniaturized devices should provide support for all ages from newborns to teenagers. The rotary pumps, particularly magnetic levitation devices, may be more suitable for infants. It is imperative that congenital heart surgeons keep fully apprised of the progress of these systems so they can be made available as soon as possible. Similarly, the use of biventricular synchronized pacing to treat congestive heart failure has been limited to the adult population [49]. Recently, Kanter and colleagues have used a miniaturized system to treat children awaiting heart transplantation with good results [50].

Two new right ventricular conduit applications were recently reported. Brown and colleagues [51] used a bovine jugular conduit that contains a venous valve (Contegra, Medtronic Inc, Minneapolis, MN) and Kanter and colleagues used the Freestyle porcine root for right ventricular outflow tract reconstruction [52].

Minimally invasive repair of some congenital heart defects has become possible. Hines and colleagues continue to perform closure of patent ductus arteriosus with thoracoscopic techniques which now include neonates [53]. Robotically assisted division of vascular rings has been used in children [54]. Robotically assisted division of atrial septal defects has been accomplished and may be more frequently used, although referral patterns are currently directed to cardiologists who perform catheter-based closures of atrial septal defects and patent ducti arteriosus. Closure of muscular ventricular septal defects was accomplished recently by Bacha and Associates by combining an open surgical approach with the Amplatzer closure device (AGA Medical Corp, Golden Valley, MN). Cardiopulmonary bypass was not required for closure of the defect [55].

Congenital heart surgeons will continue to pursue techniques to allow for minimal scarring, discomfort and hospital stays for infants and children, while ensuring that technologies developed for the adult population will also be made available to the pediatric population as expeditiously as possible.


   General Thoracic Surgery
Top
 Introduction
 Coronary Bypass Grafting
 Heart Failure
 Valvular Surgery
 Congenital Heart Surgery
 General Thoracic Surgery
Footnotes
 References
 
An excellent recent review of what's new in general thoracic surgery by Feins and Watson discussed two novel types of treatment for localized lung cancer [56]. Radiofrequency ablation was used in medically unresectable patients with a radiographic response in the majority, but because of the potential morbidities, the authors believed this treatment would be safest if performed by thoracic surgeons [57]. Another trial studied radiosurgery for lung tumors in which a single dose of 1500 cGy was delivered by the Cyberknife system [58]. These authors proposed that general thoracic surgical oncologists in collaboration with radiation oncologists should pursue the development of stereotactic radiation for lung cancer.

The scope of video-assisted thoracic surgery (VATS) has been expanded to include major areas of general thoracic surgery including thoracic sympathectomy, spine surgery, lung cancer, esophageal cancer, lung volume reduction surgery (LVRS) and mediastinal tumors [59]. The accuracy of staging for non-small cell lung cancer (NSCLC) may be improved by sentinel lymph node retrieval using VATS techniques which when combined with immunohistochemical methods may provide better detection of occult micrometastases. VATS lobectomy seems to provide equivalent outcomes in terms of tumor resection, lymph node sampling and postoperative pain, while the cosmetic result is clearly better but the effect on long-term survival is not yet determined [59]. Minimally invasive techniques are also being applied for benign esophageal disease, but only by a few groups for esophageal cancer [60]. However, the advancement of thoracoscopic/laryngoscopic procedures in esophageal carcinoma has made staging more accurate and definitive. Robotic-assisted minimally invasive transhiatal esophagectomy has been performed successfully [61].

Significant advances are being made toward the treatment of patients with acute and chronic respiratory insufficiency [62]. A respiratory catheter consisting of a bundle of hollow fiber membranes with a rapidly pulsating balloon to enhance gas exchange has been designed to be inserted into a peripheral vein of patients with acute respiratory insufficiency [63]. This "intravenous membrane oxygenator" (IMO) may compete favorably with extracorporeal life support (ERSL) using arteriovenous or venovenous cannulation with an external membrane oxygenator. Another simple device utilizing chronic arterial and venous cannulation and the patient's own blood flow provides CO2 removal in patients with acute respiratory decompensation. A total artificial lung (TAL) (Biolung, MC3 Inc, Ann Arbor, MI) is being designed with a variable compliance chamber to support the right ventricle during TAL operation [64]. These devices are on the cusp of active clinical applications in the large population of patients with chronic obstructive pulmonary disease in the United States.

Within the last few years vascular surgeons have converted increasing numbers of their open surgical procedures to endovascular techniques. This trend has been much less prevalent in thoracic surgeons treating thoracic aortic aneurysms, but transition is rapidly accelerating with the introduction of new modular devices which can be inserted in the transverse and descending thoracic aorta [65]. While the use of these devices holds enormous promise for patients and thoracic surgeons, the commitment of time and resources to perfect these techniques will be demanding, often necessitating an interruption of a busy practice to spend time devoted to a training period or "fellowship" in this technology. This type of commitment to learning new technology and in the process "reinventing" ourselves as cardiothoracic surgeons is the challenge we face today and over the next few years.

As noted in the beginning of this address, the decreasing number of patients being referred for CABG [2, 3] has created considerable concern among cardiac surgeons as to future operative case volumes. In Figure 1, data from the Cardiovascular Roundtable [18] indeed support the projection of a seven percent decrease in CABG volume from 2003 to 2008. However, projections also include a 14% increase in valvular surgical cases, and a marked increase in the modified and minimally invasive procedures for atrial fibrillation. Heart failure surgery is projected to increase significantly as well. Total cardiac surgical cases are predicted to increase by six percent over the five year period. These data suggest that cardiac surgeons will have ample surgical cases over the next five years. The subject of surgeon reinbursement for performing these cases is not addressed in this discussion, but will continue to require a committed focus by our professional societies.

Without doubt this discussion has led many of us to be fondly reminiscent of the "good old days" when we drove our big muscle cars without concern for the consumption of inexpensive gasoline or the quality of our air. As surgeons, we made big surgical incisions because, after all, "the wound healed from side to side and not from end to end". The only way to the lungs and esophagus was through a thoracotomy, since thorocoscopy hadn't been developed. The only way to operate on the heart was by using cardiopulmonary bypass and cardioplegic arrest so the heart lay quiet and still while we sewed, unencumbered by a beating heart. Robots were only seen in movies. We began our residents' training by teaching them to close atrial septal defects and patent ducti arteriosus, defects now often closed by cardiologists. There was a never-ending abundance of patients referred for coronary artery bypass grafting and cardiologists were principally diagnosticians, rather than interventional competitors. Alas, those days are just as surely gone as the beloved Oldsmobile and we must now embrace the new technology, if necessary, reinvent ourselves to respond to current surgical demands and fashion from this rich bank of new technological devices the safest, most effective, and beneficial procedures to care for our patients. These new procedures will cause less pain and discomfort, shorten disability, allow quicker return to work, and yet provide long-lasting solutions for our patients. I urge you to join in this new adventure, ever mindful of the words of the Almighty to his servant Jeremiah—"Call to me and I will answer you, and show you great and mighty things which you know not!" (Jeremiah 33:3).


   Footnotes
Top
 Introduction
 Coronary Bypass Grafting
 Heart Failure
 Valvular Surgery
 Congenital Heart Surgery
 General Thoracic Surgery
 Footnotes
References
 
Presented at the Fifty-first Annual Meeting of the Southern Thoracic Surgical Association, Cancun, Mexico, Nov 2–4, 2004.


   References
Top
 Introduction
 Coronary Bypass Grafting
 Heart Failure
 Valvular Surgery
 Congenital Heart Surgery
 General Thoracic Surgery
 Footnotes
 References
 

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