Prior to the Development of the Cardiac Stent,surgeons Used Balloons

Multiple Choice

Prior to the development of the cardiac stent,surgeons used balloons to clear obstructed heart vessels,but there was no way to ensure the vessels would stay open.The stent is a tiny metal scaffold that props open the formerly obstructed blood vessel and keeps it from becoming obstructed again.Surgeons who use the stent had to engage in a great deal of learning to understand its use and how valuable a tool it was in patient care.There was nothing like the stent on the market when it first appeared.The cardiac stent was an example of a .

A) competitive innovation
B) nonradical innovation
C) dynamically continuous innovation
D) discontinuous innovation
E) continuous innovation