[Risk factors in stable coronary disease. Relationship with ischemic threshold and prognostic implications].

BACKGROUND

To assess the clinical evolution, in a 5-year follow-up, of the development of acute coronary syndromes, in patients with angina clinically stable, establishing its relationship with the ischemic threshold (IT) and the main modifiable cardiovascular risk factors.

PATIENTS AND METHODS

120 patients, 86 males (71%), with an age of 57 +/- 8 years, with stable angina. The presence of smoking, hypercholesterolemia, hypertension and diabetes mellitus was evaluated. We performed exercise testings (baseline and after vasodilator drugs) in the beginning, in order to characterize the IT (which was fixed in 72 patients and variable in 48). The later group underwent exercise testing each term during the first year of follow-up. Lesion at least of 70% in a main coronary vessel was required as inclusion criteria. The development of acute myocardial infarction (AMI), unstable angina pectoris and cardiac death was recorded. Cox's hazard function analysis and multivariant analysis were applied.

RESULTS

106 patients (88%) had one or more risk factors (40% hypertension, 43% hypercholesterolemia, 22% diabetes mellitus and 56% were smokers or ex-smokers). A significant association was shown between male gender and smoking and diabetes mellitus and female gender. 6 cardiac deaths, 8 AMI and 9 unstable angina were recorded. Within the 72 patients with fixed IT, 12.5% (9) suffered some acute syndrome. In the 48 with variable IT, in the 30 who continued in it, 20% (6) developed acute coronary pathology and in the 18 who modified their IT to fixed, the prevalence was 44.5% (8). Patients with modification of IT to fixed had a higher risk of acute coronary syndrome in the follow-up (p < 0.01) and the presence of hypertension and hypercholesterolemia allowed the prediction of modification of the IT.

CONCLUSIONS

The prevalence of cardiovascular risk factors in the stable coronary artery disease is high (88%); male gender is associated smoking and female gender to diabetes mellitus. The presence of hypertension and hypercholesterolemia are associated to modification in the IT in patients with variable threshold, allowing the detection of a subgroup of high risk for the development of acute coronary pathology.