Which leads to more plaque formation - higher LDL cholesterol content or higher LDL particle number?
The traditional testing for cholesterol measures the amount of cholesterol within the LDL particles. LDL is a carrier for cholesterol. Apo B100 is a main protein component of LDL. Atherosclerotic plaque is the result of chronic inflammatory response to oxidized LDL particles within the arterial wall, not due to the cholesterol content itself.
In the above example, the LDL cholesterol is 85 in both A and B. In A, the LDL particle is larger and is able to carry more cholesterol than B. Two LDL particles in A carry as much cholesterol as three LDL particles in B. Patient B has more LDL particles than Patient A while LDL cholesterol level is the same. LDL-P in Patient A is 900. LDL-P in Patient B is 1250. The treatment goal is LDL-P less than 1000.
Knowing the LDL cholesterol level is not enough. The greater the number of LDL particles floating in the blood, the greater the risk. Treatment is aimed to reduce the number of LDL particles to below a target level depending upon the level of risk.