ITs a combination of factors depending on the compounds you use and the dosages/duration you use them for.
AAS can (in some people):
-increase LDL, ultimatley increasing you chances of a plaque breaking off and causing a stroke or a jammer
-increase blood pressure (via water retention, increased blood volume, narrowed ateries etc)
-can cause hypertrophy of the left ventricle .... things is, weight training naturally can do this ; however, an AAS enlarged left ventricle tends to be more rigid than a naturally enlarged left ventricle and doesnt shrink as much even after cessation of AAS. (I dont feel like looking up the case study ... basically 2 twins brothers, 1 used AAS for 20 years, 1 just lifted, and that what ahppened to their hearts)