An angioplasty catheter includes an elongated carrier, and an angioplasty balloon about the carrier in sealed relation thereto. The balloon is arranged to receive a fluid therein that inflates the balloon. The catheter further includes a shock wave generator within the balloon that forms a rapidly expanding and collapsing bubble within the balloon to form mechanical shock waves within the balloon. The expanding bubble forms a first shock and the collapsing balloon forms a second shock wave. The shock wave generator is arranged such that the energy of the first shock wave is greater than the energy of the second shock wave.