Trial to Assess Chelation Therapy in Critical Limb Ischemia

Inclusion Criteria: * Age ≥ 50 years * History of diabetes, defined as medical record evidence or patient report of currently using insulin or oral hypoglycemic agents, or with a history of fasting blood glucose measurement of 126 mg/dL or higher, or a history of HbA1c of 6.5% or higher. * Significant stenosis (≥ 75%) of two or more infra-popliteal arteries in the affected limb as verified by at least one imaging technique (angiography, magnetic resonance angiogram, coronary computed tomography angiogram, or doppler examination) within 6 months prior to enrollment; * History of CLI defined as moderate or high-risk infra-popliteal chronic critical limb ischemia (Rutherford Clinical Severity Score 4 or 5) defined as: * The presence of rest pain or non-healing ulceration or gangrene for at least 2 weeks plus documentation of severely compromised tissue perfusion: * If there is tissue loss, a resting ankle systolic pressure of ≤ 60 mmHg in the affected limb; or a resting toe systolic pressure of ≤ 40 mmHg or a tissue perfusion pressure (TPP) \<40 mmHg. * If there is no tissue loss, a resting ankle pressure of ≤ 50 mmHg or resting toe systolic pressure of ≤ 30 mmHg or a tissue perfusion pressure (TPP) \< 30 mmHg. * Not a candidate or a failed candidate for surgical or transcatheter revascularization; * Able to give informed consent. Exclusion Criteria: * \<7 days following lower extremity (infra-popliteal), carotid, or coronary revascularization. * Arterial insufficiency in the lower extremity as the result of a non-atherosclerotic disorder. * Subjects with evidence of active infection (e.g., cellulitis, osteomyelitis) or deep ulceration exposing bone or tendon or extensive heel ulceration * Subjects with extensive gangrene extending above the MT joint * Subjects in whom there is severe pain at rest uncontrollable with pain medications * Prior intravenous chelation therapy consisting of \> 1 infusion within 5 years; if only 1 infusion took place, patient cannot be enrolled for at least 12 months after said infusion. * Oral chelation with an FDA-approved chelating agent within 2 years * Allergy to any components of the study drug * Planned leg revascularization within 1 month of enrollment * Symptomatic or clinically evident acute heart failure * Heart failure hospitalization within 3 months * Blood pressure \>160/100 * No venous access * eGFR \< 30 mL/min per 1.73 m2 or lower (CKD stages 1-3) calculated with MDRD * Known or suspected acute kidney injury using prevalent KDIGO criteria45 * Platelet count \<100,000/mm3 * Cigarette smoking within the last 3 months * Liver disease or Alanine aminotransferase (ALT), aspartate aminotransferase (AST) \> 2.0 times the upper limit of normal (this will require clearance by the Study PI) * Diseases of copper, iron, or calcium metabolism (other than osteopenia or osteoporosis, or simple iron deficiency). These require evaluation by the Study PI * Inability to tolerate the study-required fluid load * Other medical condition likely to affect patient survival within 3 years * Women of child-bearing potential * Any factor that suggests that the potential participant will not be able to adhere to the protocol.