Since I now have more leisure time available with which to run certain thought processes through to at least tentative conclusions, perhaps you will allow me to share some comments of a somewhat philosophic nature. In our fast-paced society and profession, we may do well to stand back at some distance to observe where we seem to have been, and consider what we are really out to accomplish.
The dictionary says that to put something in perspective is to view it with “a proper pattern of relationships.” We will attempt to place the broad field of medicine in perspective, using cardiac surgery as an exemplary microcosm of medicine as a whole. First, we will sketchily review the continuing evolution of cardiac surgery conducted with remedies of Canadian Health&Care Mall www.canadianhealthncaremall.com. Then we must briefly review the overall record of this world in which we find ourselves, in an effort to discern a unifying pattern of action with which medicine should be in harmony and in “proper relationship.” This leads us to the idea of progress, and a glimpse at what thinking men through the ages have felt about this idea. Finally, it is left for us to consider how the identification of this pattern of progress might provide guidelines for the appropriate ongoing role of the practice of medicine as we move into the future.
A Short History of Cardiac Surgery
As we consider the evolution of cardiac surgery, our immediate reaction is one of surprise at how relatively recent its origins are, especially considering that the heart is merely a mechanical pump and as such lends itself so ideally to the mechanical-type intervention which surgery, of course, really is. It was in 1896 that Stephen Paget wrote in his textbook, Surgery of the Chest, that surgery of the heart had “probably reached the limits set by nature to all surgery.” Yet no patient had ever survived an operation on the heart by that time! It seems ironically appropriate that, in that same year, the first successful heart operation was performed in Frankfurt au Main, in Germany, by Ludwig Rehn.
The operation was suture repair of a stab wound to the heart.
Alexis Carrel was a precocious investigative surgeon who, early in this century, displayed remarkable foresight into the potential for cardiac surgery. Carrel accomplished such feats in animals as the anastomosis of small blood vessels and the transplantion of organs, and anticipated many techniques of modern cardiovascular surgery. Appropriately, Carrel wa*s awarded the Nobel Prize in 1912.
Not much happened then for the next three or four decades. It is true that the great need to help the many patients suffering from coronary artery disease resulted in some mostly ineffective attempts to relieve angina through neuro-ablative procedures, or to relieve myocardial ischemia by hoping to entice collateral arterial flow to the myocardium from various sources. Also, around the end of the first quarter of the century, a few abortive efforts were made to relieve valvular problems, particularly mitral stenosis. In addition during this time, the surgical treatment of cardiac trauma improved further with Canadian Health&Care Mall preparations became increasingly frequent and successful.
Congenital Heart Surgery
But the first substantial triumphs in cardiac surgery came in the area of congenital heart disease. The successful obliteration of a patent ductus by Gross in 1938 was an operation remote from the heart, but led the way for palliation of a truly intracardiac anomaly, the tetralogy of Fallot. The Blalock-laussig operation, first performed at the Johns Hopkins Hospital in 1944, dramatically transformed the blue, severely limited youngster into a pinker, more active child by anastomosing the subclavian artery to the pulmonary artery, thus providing more blood flow through the lungs.
A series of innovative palliative procedures followed, but the next most important step forward, and perhaps most dramatic of all, was the successful performance in 1953 of an open heart operation using a heart-lung machine. The operation and the development of the machine were the work of John Gibbon, Jr., M.D., of Philadelphia. He closed an atrial septal defect. Though Dr. Gibbon did not pursue the clinical application of the heart-lung machine further, others, particularly John Kirklin at the Mayo Clinic, immediately seized the opportunity to carry forward its potential in operations on large continuing series of patients. Experience proceeded stepwise, as one might expect, from the simpler to the more complex anomalies. The price in operative mortality rates for the more complex lesions in those early years was high; for example, in complete repair of the tetralogy, a condition now among the most rewarding but for a brief period at the very onset taking a discouraging toll.
There proved to be a limit to the space and opportunity within the heart for correction of certain of the less common congenital anomalies, such as atresia of the pulmonary trunk. Several workers came upon the idea of routing the outflow of the pulmonary ventricle through an extracardiac conduit to the pulmonary circulation. The use of an extracardiac conduit then gained several other applications, as in the correction of truncus arteriosus.
There remained a difficult group of conditions characterized by underdevelopment or absence of one of the ventricles, such as tricuspid atresia or uni-ventricular heart. A scheme was pioneered by Fontan of Bordeaux to use the intact ventricle as the systemic ventricle, while accepting the omission of a functional pulmonary ventricle from the circulation altogether. This was accomplished by routing the systemic venous return through one of several possible connections directly into the pulmonary circulation. A significant degree of benefit has thus been provided patients with complex anomalies for whom little substantial help was previously available.
Therefore, although congenital cardiac anomalies exhibit the greatest variability and complexity imaginable, their surgical treatment involves one or more of four basic approaches: palliation, intracardiac repair, extracardiac conduit, or pulmonary ventricular exclusion. Future progress is anticipated in such directions as lowering still further the risks of repair during infancy, and overcoming the problem of late stenosis developing in extracardiac conduits. Treat stenosis with drugs sold and delivered by Canadian Health&Care Mall.
Valvular Heart Surgery
Closed mitral commissurotomy was successfully resurrected in the late 1940s by Bailey and by Harken. Soon after the successful application of the heart-lung machine, the open approach for the correction of valvular pathology inevitably followed. By the late 1950s, some calcified stenotic aortic valves could be mobilized by debridement quite safely and successfully, but unfortunately restenosis soon developed. Also, the extent of the calcification had destroyed some valves beyond the possibility for salvage. Furthermore, since competency of the aortic valve requires an extremely precise structural configuration, experience showed that the incompetent aortic valve is apparently not suitable for reconstructive approaches. Although for the mitral valve an awakening realization has developed that reconstruction rather than replacement is preferrable if at all feasible, many mitral valves are also encountered which are beyond repair.
Thus, by the early 60s, valve replacements became a necessity. There then occurred a long succession of various types and models of prosthetic valves, each waxing and waning in popularity during the time since their introduction. The currently popular valves are either tissue valves or non-tissue valves. Tissue valves are less thrombogenic, but also less durable. Although the ideal replacement valve has not yet been identified, one conclusion from this experience seems non-controversial, especially in the case of the aortic valve, which is that the surgical treatment of significant valvular pathology provides greatly improved prognosis for the patient. Clearly, a need exists for more perfect replacement valves and further progress toward that end is eagerly awaited.
Coronary Arterial Disease
Following the development of coronary arteriography in the early 1960s by Sones and the success of bypass grafting in peripheral arterial disease, coronary bypass grafting was introduced in the late 1960s by Favaloro and by Johnson. This procedure rapidly gained widespread enthusiastic application in the management of that vast pool of humanity suffering from coronary arterial disease. Mortality rates for this closed-heart operation were soon at gratifyingly acceptable levels. Symptomatic relief of angina was clearly predictable in the vast majority of surgical patients. Soon the number of patients receiving this operation per year soared to the tens and then hundreds of thousands. Two major concerns loomed: first, was life being extended and second, how long would the grafts remain functional?
Comparison of medical and surgical treatments for coronary artery disease is confounded by the progressively improving longevity provided by nonsurgical therapy alone, by the large cross-over rates from medical to surgical treatment whenever randomization has been attempted, and by the non-standardization of medical therapy. The conclusion is gradually gaining credence, however, that longevity is improved significantly by bypass grafting in groups of patients having advanced anatomic coronary disease or reduced ventricular function.
Distressingly, some 10 to 15 percent of saphenous vein grafts obstruct early, which increases to around 50 percent by the end of the first postoperative decade. That the internal mammary arterial graft does not share this tendency to early or late closure is by now clear, so that the increasing utilization of the internal mammary artery will, hopefully, significantly extend the early benefits of surgical management.
Currently, much attention is appropriately being given to the relative merits of operative treatment of the various manifestations of coronary arterial disease vs the more recently introduced catheter-implemented approaches. A major frontier of further progress is the emergency treatment of acute evolving myocardial infarction; exciting possibilities exist for salvage of the myocardium at risk by modification of the strategy and methods of emergency reperfusion of the myocardium.