Variations in lipoprotein levels after myocardial infarction and unstable angina: the LATIN trial.

Background: The aim of this study was to prospectively evaluate the magnitude of the variations in lipid levels in a large population of patients admitted for acute myocardial infarction (MI) and unstable angina (UA). Clinical data and blood samples were prospectively collected from consecutive patients with MI and UA.

Methods: The study population consisted of patients with symptoms lasting < or = 12 hours (for MI) or with the last episode of rest pain within 12 hours and associated with ECG changes (for UA). The exclusion criteria were recent hospitalization for any reason or current treatment with lipid-lowering drugs. Blood samples were obtained at admission, the following morning, at discharge and after 3 months. Samples were centrifuged immediately and 4 aliquots of serum were stored at -20 degrees C. The measurements were performed centrally.

Results: We enrolled 1864 patients (1275 with MI and 589 with UA). Serum levels of total and LDL-cholesterol decreased significantly after admission, both in MI and UA patients. After 3 months, serum levels of total cholesterol returned to baseline, while those of LDL-cholesterol were still significantly lower. Between admission and the following morning, total and LDL-cholesterol decreased significantly by 7 and 10% respectively for MI and by 5 and 6% for UA. Lipid measurements not performed at admission accounted for a significant decrease in the number of patients identifiable as hyperlipidemic and suitable for lipid-lowering treatment (18% of MI patients and 11% of UA patients).

Conclusions: Serum cholesterol concentrations drop significantly during hospitalization for an acute coronary syndrome after a few hours from admission to the coronary care unit. Lipid profile assessment should be scheduled at admission in order to correctly identify hyperlipidemic patients.