Atheroma Morphology and Mechanical Strength

Acute clinical cardiovascular events remain the main cause of morbidity and mortality in industrialized societies. Corroborating evidence obtained from classical pathological observation and state-of-the-art imaging shows that fatal events are mainly due to thrombosis triggered by exposure of a disrupted atherosclerotic plaque contents, rather than to obliteration of blood flow by the plaque bulk. Thus, the time has finally come to concentrate on the factors that may weaken the structure of a plaque to precipitate its sudden disruption. Recent studies have identified morphological characteristics likely to be associated with a plaque’s tendency to rupture, underlining the possibility to clinically use such hallmarks to predict, control, and monitor plaque evolution.From a mechanical point of view, the delicate balance of plaque stability is controlled, on one hand, by the intrinsic properties of the tissue and, on the other hand, by the external forces to which the plaque is subjected. On the basis of circumstantial evidence, an increased content of lipid and a decreased content of collagen have been long suspected to decrease the mechanical strength of the plaque1 ; however, no direct proof has been offered so far. In a study published in this issue of Circulation Research , Rekhter et al,2 starting from this hypothesis, manipulated the composition of experimental lesion through dietary lipid loading, and then they examined the first side of this equation, ie, the relationship between collagen and lipid content and the mechanical properties of lesions. By demonstrating such a relation, albeit in an experimental model of plaque rupture and without specifically addressing the mechanisms, Rekhter et al2 have moved present assumptions regarding plaque stability closer to validation. As an important practical application, this study gives impetus to the development of clinical tests based on morphological characterization of collagen/fat content to predict and monitor …