Strategy for evaluation and surgical treatment of the asymptomatic or mildly symptomatic patient with coronary artery disease

Although there is no debate concerning the role of operation in severely symptomatic patients with coronary artery disease, uncertainty concerning the indications for coronary bypass operation in the asymptomatic or mildly symptomatic patient abounds. Preliminary results of the Veterans Administration Collaborative Study indicate that operation enhances survival only in patients with left main coronary artery disease. The debate this study engendered led to analyses questioning the validity of its conclusions. By utilization of nonrandomized data, it was argued that operation also increases survival in patients with significant narrowing of two or three coronary vessels. The survival data of the nonsurgically treated groups in such studies derived mainly from natural history data of populations studied 5 to 10 years ago and containing large numbers of severely symptomatic patients: The annual mortality rate in such populations has averaged about 7 and 11 percent in patients with two and three vessel disease, respectively. However, recent studies indicate that survival of asymptomatic or midly symptomatic patients with two or three vessel disease is considerably better: These patients have an average annual mortality rate of only about 2 percent. Thus, when survival data of surgically treated patients are compared with survival data of asymptomatic or mildly symptomatic patients not treated surgically, serious questions arise as to the wisdom of prophylactic operation in patients without left main coronary artery disease. Because a compelling argument can be made for operating on all symptomatic patients with left main coronary artery disease it might be justified to perform coronary angtography in all symptomatic patients with coronary disease to rule out the possibility of significant left main arterial narrowing. Alternatively, etectrocardiographic exercise stress testing may offer a reasonable alternative to determine which mildly symptomatic patients should undergo coronary angiography for detection of this disease. However, the profound economic implications of such screening studies must be considered before broad application of large scale screening is advocated.