Lexie and Mark performed a gluteoplasty on Christy. As you saw, a gluteoplasty can either be a surgical lifting or augmentation of the buttocks. It's all good to want more (or higher) junk in the trunk, but make sure you find a credible doctor: a botched gluteoplasty led to the death of Solange Magnano, a Miss Argentina winner.
Cristina's patient Roy developed cor pulmonale, which happens when high blood pressure in the arteries of lungs prevent the right ventricle of the heart to pump blood through them. (FYI, the right side of the heart is responsible for pumping blood through the lungs while the left pumps blood to the rest of the body.)
Speaking of hearts, April guarded her dummy patient from Owen's complication-card which would have said that the patient has cardiac tamponade. This is a condition in which blood or fluid accumulates between the myocardium and the pericardiuam — i.e. between the heart muscle and the outer covering of the heart. This build-up compresses the heart and impedes it from pumping efficiently.
Sources: Wikipedia, MedlinePlus, and MedlinePlus