This guy was almost certainly taking testosterone as a base for whatever stack of steroids he was using. One of the big issues with steroids is to keep an eye on your hematocrit while on. As you increase the androgenic load, your body upregulates erythropoiesis. It makes more red blood cells. This can be beneficial to a point as having more red blood cells gives the same benefits as high altitude training on performance. The big drawback is that it can make your blood thicker and thicker as you make more rbc’s. After a point, this will increase your clot risk and thick blood is linked to cardiovascular issues in the long term. Guys will try to get around this by periodically going to a phlebotomist to bleed off some of the extra rbc’s they make to keep things in a normal range. Bottom line is that anyone who uses a lot of gear should consider themselves as an increased clot risk regardless of their biomarkers. Depending on what you take, you can also have increased blood pressure which is bad for the kidneys and any aneurysms you may be developing.