INTRAMURAL CORONARY-ARTERY DISEASE IN SWINE WITH NATURALLY-OCCURRING HYPERTROPHIC CARDIOMYOPATHY

Intramural coronary artery disease (ICAD) has been reported in myocard ium affected with hypertrophic cardiomyopathy (HCM), but has never bee n studied in detail with respect to the cell type or lipid infiltratio n involved in the wall-thickening. The lack of heart samples may be on e of the rationales to hamper the progress in investigating this disea se. Recently, the discovery of naturally occurring HCM in swine has pr ovided an excellent opportunity for the study of ICAD because of the h igh prevalence of ICAD in this animal. The present study provides a de tailed structure feature in the thickened arterial wall of ICAD by bot h histologic and electron microscopic means. Morphologically, the feat ure of ICAD is due primarily to the neointimal thickening. Smooth musc le cells (SMC) and extracellular matrix (collagen and elastic fibers) are the major components responsible for the thickened neointima. Frag mentation of the internal elastic membrane is associated with the migr ation and proliferation of SMC from the media to the intima. Therefore , pigs with HCM may be a potential animal model not only for the study of the mechanism by which SMC migrate and proliferate into intima, bu t also for the future investigation of interventions in coronary arter y occlusion.