This is important to know. I wasn't told of the risk, and one evening I started having severe chest pain. I thought I was having a heart attack. When it didnt improve, we talked 911. The ambulance ecg was unremarkable. Luckily, the cardiologist that I used to work with immediately suspected the problem and sent me for a CT. My lungs were filled with clots. There were discussions of whether surgery was needed. They also found clots up and down my arms and legs. Patients should know that this is a serious risk even if it is uncommon.