Editorials

Surgical Treatment of Coronary Artery

Disease: Too Fast, Too Soon?

ARTHUR SELZER, MD, FACC WILLIAM J. KERTH, MD

San Francisco, California

The most recent advances in the surgical treat- ment of coronary artery disease have thrown this subject into turmoil. The enthusiasm generated by the introduction of techniques bypassing occlu- sive lesions in the coronary arteries is almost boundless. At medical meetings-from hospital staff meetings to major medical conventions-the impression may be gained that the problem of coronary artery disease is solved. One hears that coronary artery disease has become a “surgical” disease like appendicitis or cancer; that medical therapy is outdated ; that operations should be performed prophylactically in asymptomatic pa- tients in whom coronary artery disease happens to be present; and that coronary arteriography, a means of searching for surgical candidates, should be performed “en masse,” virtually on everyone who is at risk from coronary disease and particu- larly in patients who have uneventfully recovered from a myocardial infarction.

Such recommendations indicate the extrava- gance of claims for success of the bypass opera- tions. They are distressingly reminiscent of the claims made only 3 years ago by enthusiastic pro- ponents of the Vineberg operation. The magnitude of such claims appears at times in reverse relation to the availability of hard data to support them.

The reason for the widespread enthusiasm is easy to understand. The cardiovascular surgeon was often pleased in the past with suturing onto the heart pectoral muscle, the omentum, or any other structure within reach, with pouring talcum powder or asbestos into the pericardial sac, or with boring tunnels in the myocardium to implant open-ended vessels. Now, he can finally perform an operation that makes some sense and for which he does not have to apologize. His medical confrere who treated patients with pills-more often than

From the Cardiology and Cardiovascular Surgery Units, Presbyterian Hospital, Pacific Medical Center, and the Heart Research Institute, the Institute of Medical Sciences, San Francisco, Calif.

Address for reprints: Arthur Selzer, MD, Cardiopulmonary Laboratories, Presbyterian Hospital of Pacific Medical Center, Clay and Webster St., San Francisco. Calif. 94115.

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not without much success-is now glad to grasp at the opportunity for a dramatic “cure” of a patient with a most discouraging problem.

Assumptions underlying coronary bypass sur- gery : The “new approach” to coronary artery dis- ease is based on 4 assumptions : (1) Coronary ar- tery disease is similar to other arterial disease; for example, there is proximal stenosis and distal patency. (2) A saphenouq vein or arterial bypass to a coronary artery will have equal or better suc- cess than similar operations on diseased peripheral arteries. (3) Aortocoronary bypass predictably relieves disability from angina. (4) Aortocoro- nary bypass is capable of compensating for ob- structions to coronary blood flow in sufficient mag- nitude to alter the natural history of coronary dis- ease.

All 4 assumptions have to be subjected to a criti- cal analysis. First, the evidence from most patho- logic studies and from coronary arteriography largely supports this assumption; in about 80 per- cent of cases, the stenotic or occluding lesion is proximal, and the distal vessel remains patent with an adequate lumen to perform a successful bypass.

Second, the bypass approach is well established in vascular surgery, and microsurgical techniques have demonstrated their mettle. It is reasonable to believe that these principles and procedures may also be applicable to the coronary circulation, al- though several years must elapse before a definite answer is known.

Third, relief of angina has been attributed to a great many medical and surgical methods of treat- ment, most of which later proved worthless. The dependence of clinical manifestations of coronary disease upon the patient’s state of mind is well known: Many patients “sold” upon a new drug or nursing a scar upon their chest feel better and lose their symptoms. However, there is a basic differ- ence between improvement following bypass oper- ations and that attributed to earlier methods of treatment. The frequency and consistency with which disabling angina disappears after such op- erations are supported by objective tests, such as normalization of positive electrocardiographic

The American Journal of CARDIOLOGY

EDITORIALS

stress tests, leaving little doubt that this time a truly effective method of treatment has been in- troduced. To be sure, the success rate is not 100 percent. There are factors that may account for the persistence of angina in spite of apparently successful bypass operation : poor run-off, provid- ing too small a volume of shunted blood to relieve ischemia, revascularization of areas other than those producing ischemic pain, and the like. How- ever, this does not detract from the overall dra- matic impact of this treatment.

The fourth and most crucial assumption at pres- ent totally lacks factual support. Not only is the long-range patency of the bypass anastomosis as yet undetermined, but the natural history of coro- nary disease is not well enough known to enable one to project the influence of any therapy upon it.

Impact of coronary arteriography: The last decade saw the introduction and wide populariza- tion of selective coronary arteriography ; the dra- matic impact of correlating occlusive coronary le- sions with clinical manifestations of coronary dis- ease led to better understanding of ischemic heart disease. Yet, the value of coronary arteriography may have been overemphasized. In the first place, technical factors play an essential role: Only the best films with multiple rotational views show enough detail to permit reliable interpretation. Even in the best laboratories technical perfection is not accomplished with 100 percent certainty. Furthermore, coronary arteriography has its share of unavoidable false-positive and false-nega- tiv& readings. Also, this method can tell one only by implication whether an obstructing lesion pro- duces ischemia or whether a certain clinical mani- festation is related to it. Finally, there is a miss- ing link-namely, time. After all, it may be far more important to establish the fact that a particu- lar obstructing coronary lesion is or is not pro- gressive than merely to determine that it is there.

Thus, even with the best arteriographic pictures the fate and future of a patient with coronary ar- tery disease is not known. The spectrum of coro- nary artery disease contains certain identifiable patterns. There is the patient who has an acute myocardial infarction without prior angina, recov- ers without aftereffects and is able to lead a virtu- ally unrestricted life for decades afterwards. Even laymen recognize this form of coronary artery dis- ease: The world is full of noteworthy persons, in- cluding former presidents of the United States, who survived serious heart attacks without alter- ing their lives thereafter. Then there is the patient with angina who has one infarct after another. Finally, there is the patient with a stable condition of effort angina who year after year never pro- gresses to infarction. Obviously, the first example represents an arrested form, the second a rapid progressive form and the third a partly compen-

sated, nonprogressive form of coronary artery ob- struction. But can one identify them from a single coronary arteriogram?

Long-term fate of aortocoronary bypass: Al- though the natural history of coronary artery dis- ease is not well known, that of the aortocoronary bypass is even less known, for not enough time has elapsed to know the fate of the bypass. All we know is that there is a very high rate of patency immediately after operation, and that several small series-not yet representative or consecutive or random-indicate a high rate of patency 1 year after operation. Occlusions of the bypass, early or late, do definitely occur, although we do not know their frequency. But what about 2, 5 and 10 years later? Careful follow-up studies of femoral-popli- teal bypass procedures1 show an overall patency rate of 65 percent in 5 years, with a much smaller percentage in cases with poor run-off. It may be that the coronary arteries, of much smaller caliber than the popliteal, and often afflicted with periph- eral disease, will show a higher rate of occlusion on longer follow-up studies. It may also be that because of the unique flow pattern in the coronary circulation, atherosclerosis in the bypass vessel may be accelerated. Yet current excessive enthu- siasm ignores such considerations.

Let us imagine that coronary arteriography and the aortocoronary bypass operations had been available 15 years ago, and that all patients who had a myocardial infarction between 1955 and 1960 and are well and active today underwent cor- onary arteriography and a bypass operation after the infarction. Five, 10, 15 percent. of them-de- pending upon the skill of the surgeon-would no longer be with us, as victims of the “operative risk,” The survivors would be shown off with great pride as “cures” credited to the operation!

Some years ago the National Heart Institute (now the National Heart and Lung Institute) launched a crash research program to investigate acute myocardial infarction by creating several myocardial infarction research units (MIRU). Thus far, the accomplishments of the MIRU proj- ect have been rather modest in relation to the fi- nancial investment. One cannot ignore the possibil- ity that the MIRU project is in reality chasing rainbows : Deaths caused by electrical instability were largely eliminated by the introduction of cor- onary care units ; the problem of cardiogenic shock may actually defy solution-except in the few sur- gically treatable cases-for most cases of cardio- genie shock may merely represent irretrievable de- struction of mvocardium which only cardiac trans- plantation or insertion of a permanent artificial heart may solve.

One might ask whether, rather than coneentrat- ing upon this single aspect of coronary disease, broadening the scope of research by encompassing the overall natural history of coronary artery dis-

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EDITORIALS

ease would not be a more suitable subject of a crash research program ?

Implication for selection of patients for surgery: The problem of surgical treatment of coronary ar- tery disease puts us now at a crossroad. We could take the easy path of uncritical acceptance of the new operation using it in the widest possible sense. In this case, one could only hope that the almost inevitable disillusionment would not be over- whelming. On the other hand, we can take the more difficult but prudent path of approaching sur- gical treatment with enthusiasm, but with scien- tific caution, evaluating each step very carefully, concentrating first upon the severely symptomatic patients. Surely, coronary artery disease is com- mon enough that study of such patients would

provide the immediate answer to relief of symp- toms, while permitting a justifiable long-range study of the natural history of the disease and the alteration of this history by the bypass operation. This second approach appears preferable, both for the patient and the medical profession, for more damage is likely to be done by subjecting too many patients to surgery than by carefully selecting suitable candidates-even if it is later proved that the natural history of coronary disease is indeed favorably changed by this operation and that its wide application is justifiable.

Reference 1. Baddeley RM; Ashton F, Slaney, et al: Late results of

autogenous vein bypass graft in femoropopliteal arterial occlusion. Brit Med J 1:653-656. 1970

492 The American Journal of CARDlOLO&Y