Atherogenic index of plasma: A novel biomarker and lipid indices in young myocardial infarction patients

Background: Cardiovascular diseases (CVDs) have become the leading cause of death among Indian population. It has been directly linked to hypercholesterolemia, particularly elevated plasma low-density lipoprotein-cholesterol (LDL-C) levels and low plasma high-density lipoprotein-cholesterol (HDL-C) levels. The lipid tetrad index (LTI) and lipid pentad index (LPI) have been recently described as a new form of assessment of lipid profiles. Hence, the present study was undertaken to evaluate the role of atherogenic index of plasma (AIP) and other lipid indices such as LTI and LPI in young myocardial infarction (MI) patients from North India.Methods: The present cross-sectional study was conducted in the Department of Biochemistry and Cardiology at GB Pant Institute of Postgraduate Medical Education and Research, New Delhi. A total of 240 individuals were included in the study in which 135 were patients of ST-elevation MI of the age 15-45 years, along with 105 age-matched controls during the period of July 2019 till December 2019. LTI was calculated as TC*TG*Lp(a)/HDL and LPI as TC*TG*Lp(a)*ApoB/ApoA1. AIP is calculated according to the formula: log (TG/HDL-C). Results: The lipid parameters including total cholesterol, triglyceride, LDL-C, and non-HDL-C were significantly increased in the acute MI cases in comparison to controls. HDL-C was significantly decreased in the cases. Lipoprotein (a), ApoB levels, and ApoB/ApoA1 were also significantly increased in the cases. On the other hand, ApoA1 levels were significantly decreased in the patients. LTI and LPI were significantly increased in the acute MI cases as compared to controls. On correlating lipid parameters with LTI and LPI, a significant positive correlation was observed with all lipid parameters - total cholesterol, triglyceride, LDL-C, Lp(a), and ApoB/ApoA1 except HDL-C which showed a negative correlation with LTI and a nonsignificantly negative correlation with LPI. HDL-C shows a significantly negative correlation with AIP in both cases and controls. Conclusions: This present study has evaluated Role of AIP along with lipid indices such as LTI & LPI which helps in early identification of individuals with higher risk of premature CAD. AIP can be used as a better biomarker than other lipid indices in young MI patients, especially those associated with cardiovascular risk. At present, no Lp(a)-lowering drugs have been approved, hence early identification and intervention to modify risk factor may be helpful in prevention of development of MI in these patients with the help of LTI and LPI levels.