The secondary objectives of this study are:
A. To evaluate erectile function (EF) categorical improvement in patients receiving 4 weekly treatments of shockwave therapy versus those receiving a sham treatment, at 3 months after a first sequence of treatment.
B. To compare improvements in erectile function between 4 weeks of phosphodiesterase type 5 inhibitor (PDE5i) use and 4 weekly treatments of shockwave therapy ("within patient" effect).
C. To compare improvements in erectile function between 4 weeks of PDE5 inhibitor use and 4 weekly treatments of sham shock wave therapy ("within patient" effect).
D. To evaluate the effect of a 2nd sequence of 4-8 weekly shock wave treatments 3 months after this second sequence.
E. To evaluate treatment effects (the same comparisons as in objectives A, B, C, D) on other validated measure of EF (question 2 of the sexual encounter profile (SEP2), question 3 of the sexual encounter profile (SEP3), Global Assessment Question (GAQ), Erection Hardness Scale (EHS)), and the remaining domains of the IIEF score (orgasmic function, sexual desire, intercourse satisfaction, overall satisfaction), as well as the total IIEF score.
F. To evaluate treatment tolerance and potential adverse events. G. To compare changes in EF measures over time for a follow-up period of 12 months following the second sequence of 4 weekly shock wave treatments.
H. To compare the effect of a sequence of 4 weekly shock wave treatments versus 8 biweekly shock wave treatments 3 months after the treatment ("within patient" effect).