Pathophysiology and Natural History Coronary Artery Disease

We investigated the prognostic significance of new-onset angina in patients in whom coronary anatomic characteristics were known. New onset angina was defined as angina of less than 3 months duration. Consecutive patients (n = 1727) with significant coronary artery disease (diagnosed at cardiac catheterization) and who had not had a prior myocardial infarction or congestive heart failure were studied. In patients with new-onset angina (n = 329) there was a higher incidence of single-vessel disease (43% vs 27%) and a lower incidence of triple-vessel (23% vs 35%) and left main artery (5% vs 10%) disease compared with patients with chronic angina (n = 1398). Patients were classified by the presence or absence of preinfarction angina (severe and prolonged angina at rest requiring hospitalization to rule out myocardial infarction). In patients treated without surgery and who did not have preinfarction angina, survival at year was 97% for patients with new-onset angina and 98% for those with chronic angina (p = .27). Among patients not treated surgically who did not have preinfarction angina, at 1 year 16% with new-onset angina and 7% with chronic angina had suffered a cardiac event (nonfatal myocardial infarction or death, p = .006). In patients treated surgically who did not have preinfarction angina, survival at 1 year was 96% both for those with new-onset angina and those with chronic angina (p = .99). The risk of an event in patients treated surgically at 1 year was not statistically different in patients with new-onset angina and those with chronic angina ( 12% vs 11 %, p = .27). Survival and event-free rates were lower in patients with preinfarction angina than in patients who did not have it. The nonsurgically and surgically treated patients with new-onset preinfarction angina remained at higher risk of an event than patients with preinfarction angina and a history of chronic angina. In conclusion, in patients who underwent cardiac catheterization there were no significant differences in survival rates between those with new-onset angina and those with chronic angina. However, patients with new-onset angina were at increased risk of a cardiac event, despite less severe anatomic disease. Circulation 68, No. 5, 970-978, 1983. GIVEN THE MARKED variability in the natural history of coronary heart disease, clinicians have relied on the identification of prognostic factors to help guide therapeutic decisions. The severity of the symptoms, the location of coronary lesions, and left ventricular function are among the factors that are considered in the identification of patients at increased risk of a myocardial infarction or death." 2 Controversy has arisen From the Division of Cardiology, Department of Medicine, and Division of Biometry, Department of Community and Family Medicine, Duke University Medical Center, Durham. This work was supported by contract HRA 230-76-0300 and Research grant HS-03834 from the National Center for Health Services Research and the National Center for Health Care Technology, Research grant H-17670 from the National Heart, Lung and Blood Institute, Training grant LM-07003 and grants LM-03373 and LM-00042 from the National Library of Medicine, an NIH Preventive Cardiology Academic Award, and grants from the Prudential Insurance Company of America, The Kaiser Family Foundation, and the Andrew W. Mellon Foundation. Address for correspondence: Robert M. Califf, M.D., Duke University Medical Center, P.O. Box 31123, Durham, NC 27710. Received Nov. 22, 1982; revision accepted July 14, 1983. 970 concerning the importance of the recent onset of angina pectoris as an indicator of high risk.3 I In some studies a prodrome of chest pain that precedes sudden cardiovascular death or acute myocardial infarction has been identified.5 6 The apparent inconsistency is that all patients with stable angina, most ofwhom have a relatively good prognosis, at one time had recentonset angina. The natural history and prognostic significance of new-onset angina have not been adequately characterized. Many investigators have included angina of recent onset in the definition of unstable angina.7 Within this context, the particular group with new-onset angina has been reported to be at higher risk of infarction than the remainder of patients classified as having unstable angina.8 However, results of a recent study indicate that there is a high incidence of single-vessel disease in patients with recent-onset angina.9 To our knowledge, no previous study has considered the progCIRCULATION by gest on July 6, 2017 http://ciajournals.org/ D ow nladed from -PATHOPHYSIOLOGY AND NATURAL HISTORY-CORONARY ARTERY DISEASE nostic significance of new-onset angina in patients in whom coronary anatomic characteristics were known. This investigation was designed to determine whether new-onset angina, at the time of cardiac catheterization, is independently associated with an adverse prognosis when patient history, results of physical examination, coronary anatomic characteristics, and ventricular function are known. Methods Patients. At Duke University Medical Center between November 1969 and April 1982, 3419 consecutive patients without histories of previous myocardial infarction or of congestive heart failure underwent cardiac catheterization for suspected ischemic heart disease in the presence of possible anginal symptoms. Patients who had undergone prior revascularization procedures or had congenital heart disease, hypertrophic cardiomyopathy, or valvular heart disease other than mitral insufficiency thought to be secondary to ischemic heart disease were not included. Of the remaining patients, the study population was limited to the 1727 patients who had significant coronary artery disease, defined as 75% or greater luminal diameter narrowing of one or more major coronary arteries.'0 Patient subgroups were formed based on the presence or absence of two characteristics: preinfarction angina and surgical therapy within 6 weeks after cardiac catheterization. Comparisons of outcomes in new-onset and chronic angina patients were made within each subgroup. Table 1 lists the number of patients in each group. Information system and definitions. The computerized information system, data set, method of cardiac catheterization, and follow-up system have been described in detail previously." Follow-up was 99% complete and the median follow-up time was 55 months (range 6 to 150). Definitions used in the data set have been published previously.'2 New-onset angina was defined as discomfort of less than 3 months duration that was thought to be related to ischemic heart disease. Chest discomfort of 3 months or longer duration was referred to as chronic angina. The documentation of the duration of anginal symptoms and all other patient descriptors was done prospectively at the time of cardiac catheterization. During the follow-up period, a myocardial infarction was defined as the characteristic clinical history in association with one of the following criteria: (1) appearance of a new 0.04 sec Q wave on the electrocardiogram (ECG), (2) a typical evolutionary pattern of ST-T wave changes accompanied by a transient elevation of total creatine kinase (CK) level or, if CK was not measured, appropriately timed elevations in serum lactic dehydrogenase