Complicating factors in evaluating XXXX .

@entity453 @entity850 @entity5434 @entity731
The most commonly used morphological descriptors of @entity453 are cross-sectional intimal area and "percent @entity850 ." Cross-sectional intimal area, i.e. plaque area, describes lesion size, without normalizing for differences in arterial size. "Percent @entity850 " describes the percentage of the area within the internal elastic lamina that is occupied by plaque. When using intimal area and percent lumen @entity850 data from @entity731 regression experiments there may be interpretational difficulties not only in determining the extent to which @entity731 has regressed, but also in whether or not regression has occurred. Specifically, if there if a minimal decrease in intimal area, i.e. little or no regression of atherosclerisis, and the artery becomes larger, percent lumen @entity850 will decrease, in some cases substantially, indicating improvement or "regression" of the disease. In experiments where the age, body and heart weights of baseline animals are different from those of the regression animals, part of the improvement that is seen in "percent @entity850 " may be attributable to animal growth and part to an actual decrease in intimal area. A particularly interesting, complicating factor is the apparent effect of @entity731 on arterial size. In an @entity731 progression experiment we compared coronary arteries from @entity5434 fed either a control diet or an atherogenic diet for 36 months. Ages, body weights and heart weights were similar between the groups. The animals fed the atherogenic diet had much larger coronary artery intimal areas, but also had considerably larger coronary arteriese as indicated both by area enclosed by the internal elastic lamina and lumen area. These findings suggest that in growing animals @entity731 may result in increased arterial size and thereby complicate interpretations of @entity731 progression and regression experiments.
