Future Directions in Cardiac Surgery - Part II

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Abstract

In 2006 I was asked to predict the future directions in cardiac surgery for the American Heart Hospital Journal.1 Five years later, Editor Weinberg has again asked me to comment on my predictions of 2006 to see how accurate they were and to predict where we are heading in cardiac surgery in 2011. Did any or all of my predictions come true?
This review will bring the readership up to date on the various aspects of cardiovascular surgery in 2011. What is clear is that there is now an intermix of interventional devices, surgical operations, and new technology in all areas of our field. In addition, the service-line concept for cardiac disease has become a reality in many areas of the US. It has been estimated that over 50 % of cardiologists are now working full-time for the hospitals in which they practice and many more cardiovascular surgeons are also becoming employees of the hospitals in which they practice, so this element is a major change in the practice demographics of 2006. There has been more and more pressure on the economic aspects of high-end medical therapy such as cardiology/cardiac surgery and, therefore, closer relationships between the practitioners and the hospitals in which they serve is becoming a reality to improve efficiency and decrease overall medical costs.

Citation
American Heart Hospital Journal 2011;9(1):15-8
DOI
https://doi.org/10.15420/ahhj.2011.9.1.15

In 2006 I was asked to predict the future directions in cardiac surgery for the American Heart Hospital Journal.1 Five years later, Editor Weinberg has again asked me to comment on my predictions of 2006 to see how accurate they were and to predict where we are heading in cardiac surgery in 2011. Did any or all of my predictions come true?

This review will bring the readership up to date on the various aspects of cardiovascular surgery in 2011. What is clear is that there is now an intermix of interventional devices, surgical operations, and new technology in all areas of our field. In addition, the service-line concept for cardiac disease has become a reality in many areas of the US. It has been estimated that over 50 % of cardiologists are now working full-time for the hospitals in which they practice and many more cardiovascular surgeons are also becoming employees of the hospitals in which they practice, so this element is a major change in the practice demographics of 2006. There has been more and more pressure on the economic aspects of high-end medical therapy such as cardiology/cardiac surgery and, therefore, closer relationships between the practitioners and the hospitals in which they serve is becoming a reality to improve efficiency and decrease overall medical costs.

Education and Training

I predicted that cardiothoracic surgical training would change. As I wrote the article in 2006, the American Board of Thoracic Surgery (ABTS) eliminated the requirement for American Board of Surgery (ABS) certification in general surgery as a prerequisite for ABTS certification. Before that time, four to five years of general surgery and ABS certification were required for ABTS certification. As I mentioned then, general surgery was changing, and it has changed dramatically since that time and now bears little relationship to the training areas of several decades ago when most practicing cardiac surgeons found the general surgical experience invaluable, particularly in vascular surgery. Vascular surgery has turned into an area of percutaneous catheter intervention as well as open vascular surgery and they have set their own standards and separate board certification requirements, which are also quite different from general surgery. There are now three educational formats for ABTS certification in the US. We still have the general surgery track of four years (without ABS) followed by two to three years of cardiothoracic surgery. Another track is the 4/3 program, which involves three years of general surgery, a fourth combined year of cardiothoracic and general surgery and finally three years of cardiothoracic surgery.

This gives the trainees considerably more exposure to cardiothoracic surgery, the specialty in which the individual plans to practice. Finally, a six-year program has now been established that begins straight out of medical school as an intern with six years of cardiothoracic residency all pre-established. This program currently exists in approximately 10 academic centers in the US and although no trainees have graduated from the programs yet, it is encouraging that many in these programs feel this is going to be successful. Thus, more attention is being paid to cardiothoracic surgery and much less attention is being paid to general surgery.

In addition, many practicing cardiac surgeons are now recognizing the imperative for cross-training to learn percutaneous techniques, catheter and wire skills, coronary angiography, and endovascular training for stent grafting. As percutaneous valves become more and more relevant in the treatment of patients with aortic valve disease, these techniques and training modalities will be extremely important and many cardiac surgeons are retraining.

Coronary Artery Disease

Coronary artery disease has continued to evolve with increasing numbers of patients being treated with bare-metal or drug-eluting stents. However, coronary bypass continues to be practiced extensively in the US for three-vessel disease, left main occlusion or for failed stents. Randomized, controlled studies have revealed that the long-term effects of a good coronary artery bypass operation, particularly a left internal mammary to a left anterior descending (LAD) bypass, is extremely valuable and has fewer complications and lower morbidity from cardiac-related events than do drug-eluting stents and bare-metal stents in the long term.2 Thus, there continues to be a large number of patients each year who require coronary bypass surgery on an emergency or elective basis.

There are now many units in the US that are performing hybrid procedures, particularly in elderly patients who may have three-vessel disease, which involves stents being placed to their posterior circulation and an internal mammary-to-LAD bypass performed off the heart–lung machine either through a sternotomy or a small left lateral thoracotomy. Robotic takedown of the mammary artery is atraumatic and the mammary artery bypass can be used for an off-pump left internal mammary-to-LAD bypass.3 These strategies are becoming more widespread as more hybrid operations are being performed in the US.

Although just a theory in 2006, there are now a few units in the world, particularly in China, where there are expert surgeons performing robotic coronary bypass procedures in a limited way with increasing success. Far fewer robotic coronary bypass procedures are being performed than were predicted; many surgeons in Europe have given up robotic coronary artery bypass graft (CABG) surgery and there are no robotic CABG programs of note in the US. Surgery in these patients is performed through left lateral thoracotomies and they undergo reasonable approaches with robotic technology, which has simplified the trauma involved in patients undergoing coronary artery bypass.4 More of these robotic CABGs will be performed as the technology improves and surgeons become more familiar with these techniques.

Valvular Heart Disease

Aortic Valve Disease. As noted in the article in 2006, the number of elderly people in the US is increasing and will continue to increase, therefore, there will be an increasing number of patients who have aortic valve disease. It is estimated that by 2015 there will be more than 20 million people over the age of 70 in the US. I predicted that minimally invasive aortic valve surgery would be a real boon to the elderly undergoing elective aortic valve replacement. There is now a greater recognition that elective valve replacement can be performed in patients presenting with aortic stenosis who are stable, even in the octogenarians, and sometimes even in patients over 90 years old, with a risk that is about the same as for those that are much younger. Minimally invasive valve replacement surgery has its best effect on patients in the elderly age group. A paper presented by my group at the American Association for Thoracic Surgery (AATS) a year ago on minimally invasive valve replacement in octogenarians5 showed that the operative mortality was 3 % and, more importantly, after receiving the aortic valve these patients were then transformed to a normal life expectancy for age and sex. In addition, the hybrid operation of a stent or percutaneous coronary intervention to a single vessel and then a minimally invasive aortic valve replacement is another excellent option for the elderly with combined disease.6 The number of hybrid operating rooms is increasing rapidly and is a major new therapeutic option in many valve centers throughout the US. These strategies will continue to be important. A whole session dedicated to hybrid operating rooms is planned for the AATS 2011.

Clearly, the use of percutaneous aortic valves, which will be approved by the US Food and Drug Administration probably in late 2011, will be highly important; however, for now, this approach is reserved for the truly inoperable who have serious comorbidities.7 However, the polarizing effect of the availability of percutaneous aortic valves as a treatment is the high cost and the extensive number of personnel involved. This may stimulate the formation of global payment plans for this procedure if this can prove to be an economically feasible way to treat the numbers of patients involved, particularly the elderly.

Aortic valve repair surgery continues to be performed in 2011 and the results are quite good in properly selected patients for valve repair and valve reimplantation by either the David or the Yacoub procedure. Clearly there will be controversy over who will get what over the coming years; however, it is clear that cardiologists and cardiac surgeons alike are interested in treating the elderly patient with aortic stenosis before serious comorbidities.

Mitral Valve Disease. Surgery for mitral valve disease continues to increase as the techniques for mitral valve repair become more widespread. In 2006, less than 50 % of patients that could have had mitral valve repair had the procedure. The repair rate continues to increase slowly as documented by the Society of Thoracic Surgeons database.8 It is apparent that there are many techniques that are quite simple to treat the many patients with mitral valve prolapse that are appearing in valve centers throughout the US. Indeed, these patients are being referred earlier and earlier to valve centers that do valve repair, and even the asymptomatic patients who have more than a 90 % chance of getting a repair are being referred for surgery, which is a major change in the indications for valve surgery. Mitral valve repair is the treatment for more than 90 % of patients with myxomatous valve disease.9 Treatment of ischemic mitral regurgitation or cardiomyopathic mitral regurgitation, which is really related to the extent of ventricular disease, is still in a bit of flux. The NIH is sponsoring a perspective randomized trial to evaluate repair or replacement for these patients who have primarily ventricular disease because the incidence of valve repair in this group has not proven to be as successful as those in the prolapse group.10

Although several percutaneous devices, particularly the ‘e-valve’ are being evaluated in many countries, none are as successful or as effective as the percutaneous aortic valve device. Owing to the residual mitral regurgitation that occurs with most of the devices my belief is that when approved these devices will only be used in truly non-operable cases.11 Mitral valve repair continues to be the optimal procedure for mitral regurgitation. In a few hands, robotic mitral valve has been effective.12

Tricuspid Regurgitation. There continues to be debate about treating functional tricuspid regurgitation with leftsided valve disease, although it is clear that the patients do better in the long term if the tricuspid valve is repaired at the time of surgery. Many advocate for increased tricuspid valve repair for every patient. New bicuspidization techniques13 and many different valve rings have been established to aid the surgeon in the repair of these valves. Primary tricuspid valve disease continues to be relatively rare in the US; however, in many countries, rheumatic disease has affected the tricuspid valve as well, requiring replacement of the valve.

Arrhythmia Surgery

Atrial Fibrillation is still the most common cardiac arrhythmia in the US affecting several million people. Considerable progress has been made with catheter treatment of this, but the original Maze operations have become commonplace in many centers.14 The intraoperative Maze procedure during mitral valve surgical repair for paroxysmal atrial fibrillation has proven to be extremely effective in the prevention of atrial fibrillation. There continues to be debate about chronic atrial fibrillation in patients with an enlarged left atrium. The NIH is embarking on a prospective randomized study to determine if atrial fibrillation treatment is as effective in the interventional treatment of chronic atrial fibrillation. In a few centers there have been stand-alone operations minimally invasively performed through a small thoractomy for atrial fibrillation, but these studies are still in their infancy.15

Thoracic Aortic Disease

Huge advances in endovascular treatment of thoracic aortic disease have been made since 2006; in 2011, almost all descending thoracic aneurysms, most thoracoabdominal aneurysms, and the vast majority of abdominal aortic aneurysms have been treated by endovascular grafting.16 There have been increasing attempts over the past year to use ascending aortic stent grafts, although not as frequently as I predicted in 2006.

One of the biggest debates is who should perform these, and many peripheral vascular surgeons, interventional cardiologists, and cardiothoracic surgeons are competing in this area for these cases. Again, the hybrid operating room is the perfect place for these techniques to be employed and is a good stimulus for a team approach to these operations. Training of cardiac surgeons is changing to include endovascular and catheter techniques and, therefore, the cardiac surgical community will be able to perform these operations as well. In the next five years I predict major improvements in stent grafting combined with direct surgery to the ascending aorta and arch.

Heart Failure

Heart failure continues to be the most common indication for hospital admission in the US. There are increasing numbers of patients in whom medical therapeutics have been exhausted, but with improving left ventricular assist devices and artificial heart devices, implantation is happening increasingly in many centers worldwide and will continue to do so.17–19 Transplantation in the US continues to be at the 2,000–2,500 cases per year mark and so left and right ventricular assist devices will continue to proliferate. Micro pumps, small pumps, restraint devices, and other operations that improve the cardiac performance of patients with heart failure will be performed. Non-transplant operations, which I predicted in 2006, have not flourished as I had thought. Again, mitral valve repair is attempted for this group, but as indicated above it is still debatable whether valve replacement with preservation of all the chordae and papillary muscles or a small ring would be better than a mitral valve repair. The Surgical treatment for ischemic heart failure (STITCH) trial, which evaluated concomitant resection of the left ventricular dysfunctional muscle as well as coronary bypass in those with ischemic heart failure, was shown on the basis of a large prospective randomized study, not to be as effective as it was originally thought.20

Adult Congenital Heart Surgery

An increasing number of patients who have had repairs of congenital defects as children are newly diagnosed as adults with a primary congenital lesion and, indeed, the vast majority of patients who have congenital disease in the US are adults. This is continuing to be an area for case material for cardiac surgeons from an interventional, surgical, or hybrid approach where there may be some combination of percutaneous treatment plus direct surgical repair. Percutaneous valves, particularly in the pulmonic region and for aortic disease in adults, have been effective and will continue to increase.

Conclusion

As indicated by the Editor, many things have changed considerably since 2006; however, some predictions about what might have occurred by 2011 have not transpired. Many improvements have evolved, particularly in valvular heart disease and in coronary artery disease. There will be continuing tension over who will receive implantation of interventional devices as opposed to who will have definitive cardiac surgery.

There will continue to be coronary bypass, valve surgery, adult congenital repair, arrhythmia ablation, heart failure procedures, and endovascular treatment of aneurysms. The final question will be about the timing of service-line integration and who will do what procedures to which patients.

What is apparent is that for the best treatment of patients, the service-line concept needs to be increasingly followed with a complete and close collaboration between the clinical cardiologist, interventional cardiologists, cardiac anesthesiologists and cardiac surgeons to achieve the best and most long-lasting results for the individuals that are most concerned about cardiac therapy: our patients.

References
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