The Dyskinetic Discipline

The Dyskinetic Discipline

-= CHEST VOLUME 59 I NUMBER 2 I FEBRUARY, 1971 EDITORIALS The Dyskinetic Discipline eters, such as measurements of end-diastolic pressures and per...

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The Dyskinetic Discipline

eters, such as measurements of end-diastolic pressures and performances of bicycle ergometry, have demonstrated improved ventricular function in most cases. Because of these facts the proponents now suggest that the following groups of patients be studied by means of coronary arteriography and, if judged surgically acceptable, be subjected to direct coronary artery operations subsequently: l. All patients with angina pectoris. 2. All patients with pre-infarction or impending infarction syndrome as a surgical emergency. 3. All patients with acute myocardial infarction ( 6-12 weeks after the acute phase). The only exceptions would be those who for reasons of age or general physical status present an excessive surgical risk. These are radical recommendations. Those who present them argue that a large but unknown number of the estimated 650,000 people who die yearly of acute coronary disease in the United States could be saved, if these procedures were applied widely. They claim that the relative ease of the operations, their low mortality, and the indications of improved myocardial perfusion and performance are strong reasons to proceed with such surgery on a relatively mass scale. In their view the resultant need for greatly augmented services at the community hospital level must be met by much fuller mobilization of available health resources, if necessary, on a crash basis. The opponents of such views point out that widespread application of these operations would result in a major reordering of health priorities and services in this country. Many more c-ardiac surgeons would have to be trained and catheterization units opened; the great number of patients so treated would require that the procedures be available at community hospitals. They insist that before taking such a giant step, irrefutable data should be accumulated showing that there is an increased rate

At a recent panel discussion of direct coronary artery surgery, a well known cardiac surgeon referred to an equally prestigious clinical cardiologist as an "intellectual incompetent." Apart from considerations of courtesy or its absence, one was impressed by the intensity of the bitter feelings that existed. The thesis of the surgeon was that some clinicians were excessively conservative in their views of such procedures, and because of this many patients were not being benefitted by presently available operative measures. Over the past year or two a deep cleavage has developed between those who believe in the aggressive surgical management of coronary artery disease and those who are unconvinced of the universal value of such operations and are unsure as to when they should be applied. For the most part, the first group consists of skilled cardiac surgeons and younger cardiologists trained particularly in coronary cinearteriography. The opposite view is held mainly by clinical and academic cardiologists and general internists. Unfortunately, dialogues between these groups sometimes degenerate into confrontations which serve no useful purpose; they becloud an issue urgently in need of clarity. One might summarize the contentions of those who favor wide application of surgery as follows: The operations presently available, which consist mostly of aorta-coronary saphenous vein bypass grafts are relatively safe (mortality ranging from 320 percent depending upon the complexity of the procedure and the condition of the patient), and usually result in immediately increased coronary perfusion. Coronary arteriography performed at varying times postoperatively shows that only a few of the grafts become occluded and that increased myocardial oxygen delivery probably results. Angina is relieved in most cases, and objective param123


of survival and a reduced incidence of myocardial infarction in those patients surgically treated compared to a similar group given optimal non-surgical therapy, including programmed exercise. Such a study would need to be prospective, large-scale, properly controlled and randomized. These physicians state that for 25 years many different kinds of cardiac operations have been promoted for the immediate saving of lives and relief of symptoms. These have ranged from irritation of the pericardium with talc, through ligation, and more latterly implantation of the internal mammary arteries. The fact that many of these procedures have since been discarded points out the need for more careful analysis of results and appropriate follow up. They cite data recently presented by Morris 1 showing that the prognosis of those patients without risk factors of atherosclerosis who survive acute myocardial infarction is excellent, and that the hazard of aorto-coronary operation in this group likely would exceed that of no operation. They suggest that there may be other, so far unidentified subgroups of patients with coronary artery disease, in which such procedures might be similarily detrimental, and that therefore blanket recommendations for these operations are presently unjustified. There is a clear and pressing need for these two groups to sit down and talk with each other. In view of their potential impact, these operations must be evaluated properly, and some general agreement as to their place in the prevention and treatment of coronary artery disease must be reached. In medicine there should always be room for many different views; nevertheless, widely disparate and conflicting opinions on this subject do a great disservice to the practicing physician and ultimately to his patients. Means by which some consensus could be reached must be explored. Perhaps a national conference should be held in which the most vigorous and articulate exponents of these different views would participate. The goal of such a meeting would be to identify mutually agreeable ways to determine the role of these operations at this time. In reaching this objective, some of the following topics should be considered: 1. An assessment of the available information which exists about the natural history of coronary artery disease in general, and any of its subgroupings in particular. 2. An evaluation of the evidence that aortacoronary bypass operations improve ventricular function. 3. A decision as to whether a prospective, controlled, comparative study of surgical and non-


surgical therapy is now both efficacious and ethical. Such a meeting would require a general cooling of rhetoric and a commitment from those who participate to be rational, logical, and courteous.

Irwin]. Schatz, M.D., F.C.C.P.• Detroit • Associate Professor of Medicine and Chief, Section of Cardiovascular Disease, Wayne State University.

REFERENCE 1 Morris J: Symposium on Coronary Artery Surgery; Council on Cardiovascular Surgery, American Heart Association, Atlantic City, New Jersey, November 11, 1970.

Problems of Exercise Testing The electrocardiographic diagnosis of ischemic heart disease by exercise testing procedures has proved both useful and important. Single-stage submaximal exercise tests, such as the Master twoSee article, page 138 step test, have been widely used and accepted in medical practice. The two-step test has for years been a broadly recognized, valuable, standardized procedure. Of late, more sophisticated concepts have arisen in exercise testing. Multistage tests, usually performed with bicycle ergometer or treadmill, have been introduced. Criticism has been voiced against single-stage submaximal tests. The controversy is based mainly upon the fact that these tests in which the given work load is adjusted to weight, sex and age, does not take into consideration the examinees physical condition, occupation, training and leisure time habits. Thus, it may appear that the standardized work load may be too low in order to produce any change, or too high, which means that electrocardiographic changes may appear in exertions which are lower by 25 percent, 50 percent or even more, than the standardized work load. Some examinees who do not suffer from anginal pain during exertion will develop severe ischemic changes on electrocardiogram during and after a low work load performance. Although the electrocardiographic diagnosis of coronary heart disease is the most important objective of a single-stage submaximal step test, this test has been used also for the assessment of the individual's physical work capacity. The usefulness of these tests for the assessment of the physical working capability is doubtful. The reason for this is the exceedingly short period of performance which CHEST, VOL 59, NO. 2, FEBRUARY 1971