Intra-aortic balloons are indicated for:
a. Prophylactic support for PTCA or anesthesia induction, incompetent aortic valve, and cerebral stroke
b. End stage cardiac disease, incompetent aortic valve, cardiogenic shock, septic shock
c. Acute coronary syndrome, cardiac and non-cardiac surgery, and complications of heart failure
d. Brain death, sheathless insertion with severe obesity or scarring of the groin, carotid artery surgery