Angiographic evidence for the role of triglyceride-rich lipoproteins in progression of coronary artery disease

Recent developments in angiographic technology have enabled quantitative assessment of the effects of treatment on coronary arterial lesions. A meta-analysis of 12 angiographic studies showed that treatment to reduce low density lipoprotein (LDL) cholesterol levels decreases angiographic progression of coronary artery disease (CAD) by one-third, and increases the chance of lesion regression two-fold. However, these studies also show that the response to treatment to LDL cholesterol levels varies according to the severity of the coronary artery stenosis; lesions were seen to regress with treatment only if there was >50% coronary artery stenosis at baseline. Other variables that have been implicated in CAD progression include intermediate density lipoproteins (IDL), non-high density lipoproteins (non-HDL) cholesterol and very low density lipoproteins (VLDL). Levels of IDL have been shown to decrease to a greater extent in patients whose lesions did not progress than in patients showing lesion progression. In untreated patients? an increase in non-HDL cholesterol was associated with an increase in risk of disease progression. In contrast, the most important predictor in treated patients was apo CIII (a marker of triglyceride-rich lipoprotein metabolism). Possible mechanistic links between triglyceride levels and CAD progression are discussed.