Progress Of Ischemia Modified Albumin, A Myocardial Ischemia Biomarker

Objective: Myocardial Ischemia is one of the physiopathologic mechanism of coronary heart disease. Acute myocardial ischemia is a leading cause of acute coronary syndrome (ACS), which may develop reversible myocardial damage and irreversible myocardial necrosis further, which involved in higher mortality. However, the early diagnosis of ACS remains difficult. In generally, the diagnosis of ACS is according to the combination of chest pain, electrocardiographic (ECG) changes and elevation of serum biomarkers. Unfortunately, ECG missed up to 50% of these patients and the traditional biomarkers, such as cTnI/T and CK-MB are usually normal when transient and reversible myocardiol ischemia occurs without necrosis. Recently, ischemia modified albumin, a novel biomarker, which may detect myocardial ischemia with more sensitivity in early phase, is playing an important role in the diagnosis of acute myocardial ishchemia.This review is to investigate the characters of IMA in ischemic heart disease, and to evaluate the diagnostic value of IMA in myocardial ischemia.Methods: The pertinent literatures were retrievaled from databases on line. Overviewed, the recent literatures with better persuasion and better correlation were selected to analyse. And then the data of investigation about IMA in myocardial ischemia was summarized.Result: A modification of human serum albumin (HSA) caused by ischemia, with reduced capacity to bind transition metals, is the new ischemia biomarker called IMA. The precise mechanism for production of IMA is not clear, but it is speculated that it may be caused by reactive oxygen species (ROS) related to ischemia, which injures the metals-binding site of HSA. Albumin-cobalt binding (ACB) test is used to detect it.The sensitivity and negative predicitive value (NPV) of IMA for diagnosing myocardial ischemia is 88% and 92%, respectively. It increases within minutes after the onset of ischemia, remains elevation for 3 to 6 hours, and then returns to normal. IMA can also indicate the existing of myocardial ischemia early in contrast with CK-MB and cTnI/T. While in combination with cTnT and ECG, the sensitivity of IMA for diagnosing myocardial ischemia may reach 95%. The sensitivity and specificity of IMA for prognosing the 1-year mortality is 70% and 82%, respectively. On the other hands, in patients with noncardiac ischemia disease, such as pulmonary embolism, cerebrovascular disease, renal disease and peripheral vascular disease, IMA concentration may also increase. In addition, detection of IMA is also affected by age, race, HSA concentration, serum lipids levels, skeletal muscles ischemia, pregnancy and many other factors. Conclusion: IMA can be used in the early diagnosis or preclusion of myocardial ischemia, and also in the prognosis assessment and risk stratification among ACS patients. In a word, IMA is a sensitive myocardial ischemia biomarker, without higher specificity.