Risk factors in patients with different clinical and angiographic manifestations of ischemic heart disease.

In patients who present with unheralded myocardial infarction both the severity and the extent of coronary atherosclerosis appear to be less than that in patients with chronic stable angina, thus suggesting that, in the latter, protective factors may prevent or delay the evolution towards acute coronary syndromes. Therefore, risk factors were compared in 88 consecutive patients (73 men; mean age 56 +/- 9 years) with unheralded myocardial infarction and a single, discrete, > 70% stenosis in the proximal right, left circumflex or left anterior descending coronary artery (Group 1) and in 55 consecutive patients (46 men; mean age 58 +/- 9 years with chronic stable angina and multiple, diffuse, > 70% stenoses localized both in the right and left coronary arteries (Group 2). Continuous data are presented as mean value +/- 1 SD, proportions as percentages. In Group 1 mean serum levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides were similar to those in mg/dl, p = 0.93 and 160 +/- 87 vs 155 +/- 76, p = 0.74, respectively) while the mean serum level of high-density lipoprotein cholesterol was higher in Group 2 (49 +/- 4 vs 46 +/- 4 mg/dl, p = 0.005). The prevalence of a positive family history of ischemic heart disease, hypertension and smoking habit were similar in the two groups, while the prevalence of diabetes mellitus was higher in Group 2 (29 vs 6%, p = 0.001). Thus, in patients with otherwise similar coronary risk factors, higher levels of high-density lipoprotein cholesterol and diabetes mellitus appear to be associated with a reduced tendency of coronary atherosclerosis to cause acute coronary syndromes.