This study demonstrates that multivessel coronary artery disease is common in survivors of acute myocardial infarction and is especially common in patients with history of a remote antecedent myocardial infarction and in patients with angina post-infarction. Furthermore, it was found that coronary angiography could be performed safely within 30 days after myocardial infarction in stable patients and with mild risk in those having a complicated convalescence.
Although there was a greater proportion of angina in the angiography group and congestive heart failure in the non-angiography group, the post-infarction clinical convalescence and location and extent of infarction by ECG were not significantly different between those who had angiography and those who did not. Theoretically, those patients undergoing late angiography could have had progression of their disease although the percentage with multivessel disease was similar in the early angiography group (73 percent) and in all patients undergoing angiography (75 percent).
We can only speculate as to differences in the extent of coronary disease between those who had coronary angiography and those who did not Among the clinical parameters evaluated in this study, age and sex were the only significant differences between these two groups. These differences may be explained by our decision not to study asymptomatic patients over 70 years of age, and women sustaining myocardial infarctions at a later age than men. Thus, there may be differences in the extent of coronary artery disease between those who had coronary angiography and those who did not, possibly because of differences in age and sex.
The clinical characteristics of those patients having angiography (within 30 days) after myocardial infarction are shown in Table 1 and compared with those who did not have angiography soon after infarction. The group undergoing early angiography was significantly younger and consisted of more men. There was no significant difference in the location or extent of infarction as determined by ECG, and both groups had a similar percentage of patients with previous infarction. In patients undergoing early angiography, the procedure was performed at a mean of 22 days after infarction. Similarly, when all patients undergoing angiography are compared to those not having angiography (Table 1), there remains a significant difference in age and sex between the two groups.
Forty-seven of the 92 patients (51 percent) undergoing early coronary angiography had an uncomplicated convalescence, while 45 (49 percent) had a complicated convalescence. Fifty-six of the 117 patients who had had coronary angiography and 37 of the 79 patients who did not have angiography had a complicated post-myocardial infarction convalescence (Table 2). Although there were more patients who experienced only angina in the angiography group and more with congestive heart failure only in the nonangiography group, there was no significant difference in the overall distribution of complications between the two groups. Therefore, the only significant differences between the groups having angiography and those not having angiography among the parameters considered were age and sex.
Angiographic studies have shown that the severity of coronary artery obstruction and the degree of left ventricular dysfunction are two major factors influencing survival in patients with coronary artery disease. Since most patients with myocardial infarction have coronary artery disease, coronary angiography is often recommended in symptomatic patients post-infarction, but remains controversial in asymptomatic patients. Angiographic studies of survivors of myocardial infarction have suggested a high incidence of multivessel coronary artery disease treated with remedies of My Canadian Pharmacy, but most of these studies have been limited by strict selection criteria for the study population.
Angiographic assessment of patients during the acute phase of an uncomplicated myocardial infarction is not recommended, and the timing of safely performing coronary angiography during convalescence after infarction is uncertain. Although several groups have performed angiography within the first month after myocardial infarction, a waiting period of two to three months has been recommended.
The purpose of the present study was, in a consecutive series of survivors of acute myocardial infarction, to determine the distribution and extent of coronary artery disease; to determine if the severity of CAD might be predicted from clinical criteria; and to evaluate the safety of performing coronary angiography within 30 days post-infarction.