FRANCIS J. PODBIELSKI, MD, FACS
The first successful “open heart” surgical procedures were those performed for congenital abnormalities. Blalock and Taussig described a palliative procedure bearing their name for the treatment of cyanotic heart disease in 1945 . Dr. John Gibbon performed the first intracardiac operation with the aid of cardiopulmonary bypass in 1953 . Coronary revascularization for ischemic heart disease was popularized in the late 1960s. Approaches to each of these types of procedures have changed drastically with the development of new technologies. Within the scope of this review we will discuss the most frequently performed cardiac operations in the United States today, namely adult coronary revascularization and valve replacement or repair.
The gold standard against which new operative techniques are judged is a procedure performed via a full median sternotomy with central cardiopulmonary bypass. After cooling the body and heart via the pump perfusate, the aorta is cross-clamped; and antegrade, hyperkalemic solution (cardioplegia) is used to arrest the heart. This is frequently supplemented with retrograde cardioplegia and topical cold solution to the outer surface of the myocardium. Saphenous vein and/or internal thoracic arterial conduits are used to shunt blood from the ascending aorta to vessel targets on the heart. Valve replacement is accomplished by aortotomy or atriotomy. Upon completion of the bypass, repair, or replacement, the heart and body are rewarmed, the hyperkalemic coronary perfusate washed out, and the heart allowed to slowly resume its function as a pump.
As coronary revascularization became more popular, variations on the sequence of events and cardioplegic components (ie, cross-clamp removal, proximal graft anastomosis, warm vs. cold cardioplegia, blood vs. crystalloid cardioplegia) were each championed by their advocates. With the advent of new pharmacologic agents and monitoring techniques, surgeons began to re-examine the role of cardiopulmonary bypass in performing open-heart operations. One of the first “minimally invasive” techniques to be introduced was minimally invasive direct coronary artery bypass (MIDCAB). In its infancy, MIDCAB entailed a left anterior thoracotomy (usually the 4th interspace), through which the internal thoracic artery could be mobilized from the undersurface of the chest wall. After the pericardium was opened and traction sutures were placed, the heart could be rolled in the field of view and the mid-portion of the left anterior descending artery visualized. Common hand-held instruments were used to stabilize the heart. Bradycardia or intermittent cardiac arrest was achieved pharmacologically and a standard hand-sewn anastomosis performed.
Various vessel occluders, suction devices, and gas delivery systems were tried to maintain a bloodless field during the anastomosis. Currently, there are several commercially available stabilization devices that focally stop virtually all movement of the heart. This coupled with a moisturized gas delivery system enables optimal results. Drawbacks of MIDCAB include a limited number and range of target vessels . Some studies have actually shown increased pain, greater tissue destruction, and an increase in the rate of wound infections with this technique compared to off-pump coronary artery bypass (OPCAB) .
OPCAB encompasses a variety of approaches to coronary bypass grafting with one central feature – no cardiopulmonary bypass. In addition to its well-known deleterious effects on blood components and end organ function (ie, liver, pancreas), cardiopulmonary bypass has also been shown to cause long-term cognitive changes. Some investigators have actually shown cardiopulmonary bypass to be an independent risk factor for higher morbidity or mortality [5,6]. Full sternotomy OPCAB procedures offer virtually the same range of exposure as their on-pump counterparts in light of left main coronary artery disease  and poor preoperative left ventricular function . Off-pump techniques are equal in success and safety even in patients requiring emergent procedures  and those undergoing concomitant carotid endarterectomy .
Partial sternotomy and lateral thoracotomy approaches have been described with equal success. Thoracoscopic coronary anastomosis has been proven feasible, but tremor amplification via a long instrument made this technique difficult and time-consuming– until the introduction of robotics. Mechanical dampening (if not complete) ablation of human tremor and added degrees of freedom in motion have been a major breakthrough in the development of totally endoscopic coronary revascularization.
A technique developed in parallel to the surge in robotic technology has been peripheral cardiopulmonary bypass with intraaortic balloon occlusion. Using femoral vascular access, venous and arterial lines are placed. Employing special catheters and cannulae, antegrade cardioplegia can be delivered and cardiac arrest achieved. While occlusion balloon migration and aortic dissection plagued initial procedures performed with this technique, refinement of the technology and improved patient selection have overcome these issues. The hybrid technique of peripheral cardiopulmonary bypass (if needed) and robotic assistance in performing coronary anastomoses has arrived and awaits acceptance into the mainstream. Centers developing this technique usually begin with isolated left anterior descending (LAD) coronary artery to left internal thoracic artery (LITA) anastomoses with robotic assistance via a median sternotomy  until they progress to a total endoscopic operation.
Minimally invasive approaches to aortic or mitral valve operations and other procedures are varied. Total endoscopic atrial septal defect closure is now a reality  with excellent results. A popular approach to isolated aortic valve replacement is manubriotomy (upper sternotomy) and standard aortic and atrial cannulation. The entire procedure is performed through the smallest possible incision. Similarly, mitral valve repair or replacement (again with standard cardiopulmonary bypass techniques) can be performed through a small anterior or lateral right thoracotomy. Application of thoracoscopy (and now robotics) to this procedure has increased the level of repair complexity that can be performed. In one of the larger series, over 75% of coronary artery bypass graft (CABG) and mitral valve repair or replacement patients underwent an entirely endoscopic operation with results comparable to standard procedures .
In summary, the tools and technology are in place to inaugurate a new era in cardiac surgery. Acknowledging that no one operation is right for every patient, it remains the responsibility and duty of the surgeon to learn these new techniques so his or her patients can benefit from what others have so long labored to bring to fruition. Forward-thinking, proactive surgeons need to ensure that no subspecialty is left behind in the technology revolution.
This article is a synopsis of Dr Podbielski’s presentation at Endo Expo 2002.
Address reprint requests to: Francis J. Podbielski, MD, FACS, 67 Belmont St, Worcester, MA 01605-2657, Telephone: 508 334 8996, Fax: 508 334 6296, E-mail: Podbielf@ummhc.org
Francis J. Podbielski, MD, completed a general surgery residency at Columbus Hospital in Chicago and a cardiothoracic surgery fellowship at the University of Illinois at Chicago. Dr Podbielski is currently an assistant professor of thoracic surgery at the University of Massachusetts Medical Center in Worcester. He is a Fellow of the American College of Chest Physicians and serves as the Chair of the SLS Cardiac Surgery subcommittee. The application of minimally invasive techniques to general and thoracic surgery and the physiologic effects of lung volume reduction surgery on cardiac performance are Dr Podbielski’s primary research interests.
1. Blalock A, Taussig H. The surgical treatment of malformation of the heart in which there is pulmonary stenosis or pulmonary atresia. JAMA. 1945;128:189.
2. Gibbon JH Jr. Application of a mechanical heart and lung apparatus in cardiac surgery. Minn Med. 1954;37:171.
3. Gersbach P, Imsand C, von Segesser LK, et al. Beating heart coronary artery surgery: is sternotomy a suitable alternative to minimally invasive technique? Eur J Cardiothorac Surg. 2001;20:760-764.
4. Detter C, Reichenspurner H, Boehm DH, et al. Single vessel revascularization with beating heart techniques– minithoracotomy or sternotomy? Eur J Cardiothorac Surg. 2001;19:464-470.
5. Calafiore AM, Di Mauro M, Contini M, et al. Myocardial revascularization with and without cardiopulmonary bypass in multivessel disease: impact of the strategy on early outcome. Ann Thorac Surg. 2001;72:456-463.
6. Hernandez F, Cohn WE, Baribeau YR, et al. In-hospital outcomes of off-pump versus on-pump coronary artery bypass procedures: A multicenter experience. Ann Thorac Surg. 2001;72:1528-1534.
7. Dewey TM, Magee MJ, Edgerton JR, et al. Off-pump bypass grafting is safe in patients with left main coronary disease. Ann Thorac Surg. 2001;72:788-792.
8. Arom KV, Emery RW, Flavin TF, et al. OPCAB surgery, a critical review of two different categories of preoperative ejection fraction. Eur J Cardiothorac Surg. 2001;20:533-537.
9. Varghese D, Yacoub MH, Trimlett R, et al. Outcome of non-elective coronary artery bypass grafting without cardio-pulmonary bypass. Eur J Cardiothorac Surg. 2001;19:245-248.
10. Youssuf AM, Karanam R, Prendergast T, et al. Combined off-pump myocardial revascularization and carotid endarterectomy: early experience. Ann Thorac Surg. 2001;72:1542-1545.
11. Damiano RJ, Tabaie HA, Mack MJ, et al. Initial prospective multicenter clinical trial of robotically-assisted coronary artery bypass grafting. Ann Thorac Surg. 2001;72:1263-1269.
12. Torracca L, Ismeno G, Alfieri O. Total endoscopic computer-enhanced atrial septal defect closure in six patients. Ann Thorac Surg. 2001;72:1354-1357.
13. Mohr FW, Falk V, Diegeler A, et al. Computer-enhanced “robotic” cardiac surgery: experience in 148 patients. J Thorac Cardiovasc Surg. 2001;121:842-853.
www.Laparoscopy.org The Laparoscopic Surgery Information Source