Shockwave Medical, Inc. intends to conduct a prospective, single-arm, single-center, First in Human study designed to evaluate the early safety and feasibility of the Shockwave Lithoplasty System in subjects with heavily calcified infrainguinal arteries with 3.75mm to 6mm reference vessel diameter at target site. The Shockwave Lithoplasty System is indicated to generate sonic shockwave energy within the target treatment site and disrupt calcium within the lesion to allow for subsequent dilation of a peripheral artery stenosis using low balloon pressure. Up to 10 subjects will be enrolled to undergo lihtoplasty.