Influence of Glycaemia and Insulinemia on Vasomotor Endothelial Function After Ischemia/Reperfusion Lesion on Patients in Acute Phase of ST Segment Elevation Myocardial Infarction (STEMI)

The study will include patients consecutively admitted with acute myocardial infarction at State University of Campinas Hospital. Participants will be evaluated during hospitalization and, after they fulfill the inclusion criteria and sign an informed consent, it will be collected a brief medical history and recorded results from glycated hemoglobin (HbA1c), glycaemia, total cholesterol (TC), triglycerides (TG), HDL cholesterol (HDL-C), C-reactive protein (CRP), urea (U), creatinine (Cr), markers of myocardial necrosis (troponin T and CK-MB), Hemoglobin, Red blood cell, Leucocytes, Na, K, Ca and Mg.

In the first week after infarction, from admission until the realization of the clamps experiments (the medical procedure where blood glucose and insulin levels will be controlled), all medications prescribed, medical history and examination will be recorded, as well as follow-up during hospitalization.

At the day of the clamp, between 144 and 168 hours after infarction, volunteers will be randomized to one of the three situations with different glycemic and insulinemic conditions, i.e., a) high insulinemia and low glycaemia, b) high insulinemia and high glycaemia and c) low insulinemia and high glycaemia. During these experiments, endothelial vasomotor function will be recorded in four periods: i) before initiation of the procedure, ii) after 1h of the beginning, iii) 30 minutes after the second procedure and iv) 15 minutes after the simulation of ischemia/reperfusion lesion. In each time point, the investigators will collect plasma to dose inflammatory, oxidative stress and vascular activation markers.

Hospital care of subjects

The patients included in this survey will be treated according to actual guidelines. Briefly, will be enrolled patients who underwent primary angioplasty within 6 hours after symptoms onset, were introduced antiplatelet and anticoagulation therapy at the correct dose, respectively Acetylsalicylic Acid (ASA) 200 mg and Clopidogrel 300 mg, and enoxaparin 30 mg. In patients without contraindication, it will be administered in the first 24 hours beta-blockers and ACEi in those with ejection fraction (EF) <0.4, previous MI or prior heart failure. Upon admission, if there is no contraindication, simvastatin 40 mg/day will be administered. As a maintenance dose, the investigators will administer ASA 100 mg, clopidogrel 75 mg, enoxaparin 1 mg/kg twice daily, simvastatin 40 mg, propranolol 40 mg or metoprolol 50 mg (beta-blockers available at the hospital) and captopril 25 mg (most used ACEi). Patients will be treated preferably in the Coronary Unit (CU). Researchers may suggest the physician responsible for the patient care to prescribe the above medications, as well as question why the drugs listed in the guidelines are not being used. The reasons and specific contraindications will be recorded.