Admission insulin resistance index in nondiabetic patients with acute coronary syndrome: clinical and angiographic features

Abstract

Abstract Background The clinical implication of insulin resistance has extended beyond diabetes mellitus to include ischemic heart disease, dyslipidemia, hypertension, and features of metabolic syndrome. Nondiabetic patients with acute coronary syndrome and elevated admission insulin resistance index (AIRI) may have certain clinical angiographic and therapeutic strategies. Objectives The study aimed to illustrate the value of AIRI in nondiabetic patients with acute coronary syndrome and identify the angiographic coronary artery disease severity in relation to AIRI. Study design This study was cross-sectional in design. Patients and methods This study included 120 nondiabetic patients presenting with acute chest pain who were admitted to the coronary care unit. Admission glucose and insulin concentrations were measured and the AIRI was calculated. ECG was carried out and the patients were grouped as follows: those with unstable angina (UA) (40 cases) and those with acute myocardial infarction (AMI) (40 cases). They were compared with 40 patients with stable angina (SA) and a group of controls (40 individuals). The studied participants were examined clinically stressing on the other criteria for insulin resistance syndrome. The following laboratory tests were undertaken, including random plasma glucose, HBA1-c, lipid profile, cardiac enzymes (CK-MB, LDH), and troponin T. An angiographic study was carried out for patients from each diseased group and for 20 patients who had suffered a first attack in the SA group. Results AIRI was significantly elevated in the AMI (3.9 ± 0.1) and UA (3.01 ± 0.2) groups when compared with the SA and control groups. AIRI was significantly higher in the AMI group when compared with the UA group. Coronary angiography revealed one coronary vessel involvement in 10, 20, and 10% of patients in the SA, UA, and AMI groups, respectively, whereas two-vessel involvement was detected in 0, 30, and 60% of patients in the SA, UA, and AMI groups, respectively. Three-coronary-vessel disease was not detected in the SA group but was evident in 5% of UA and 30% of AMI patients. The relation of AIRI in the studied groups on the basis of the χ2-test revealed significant elevation of AIRI in the AMI and UA groups. Cases with three-vessel affection demonstrated higher AIRI. Conclusion Elevated AIRI can predict coronary artery events in nondiabetic patients with acute chest pain. Multiple coronary vessel involvement is common in such cases and suitable planned invasive therapeutic strategies have to be considered.