Consistent CTO Trial

Inclusion Criteria: * Male or female patient \>18 years old * Females of childbearing potential with a negative pregnancy test * Presence of Chronic Total Occlusion (CTO) that is known or presumed to be of at least 3 months in duration * Subject (or legal guardian) understands the trial requirements and the treatment procedures and provides written informed consent * Attempt to implant at least one Synergy II stent has been made Exclusion Criteria: * Acute myocardial infarction with ongoing ST-elevation * Cardiogenic shock * Left ventricular ejection fraction \<20% * Subject has one of the following (as assessed prior to the index procedure): Other serious medical illness (e.g., cancer, congestive heart failure) with estimated life expectancy of less than 24 months Current problems with substance abuse (e.g., alcohol, cocaine, heroin, etc.) Planned procedure that may cause non-compliance with the protocol or confound data interpretation * Subject is treated by dialysis or has a baseline serum creatinine level \>220 μmol/L (2.5 mg/dL) * Known allergy to to contrast (that cannot be adequately premedicated) and/or the trial stent system or protocol-required concomitant medications (e.g., platinum, platinum-chromium alloy, stainless steel, everolimus or structurally related compounds, polymer or individual components, all P2Y12 inhibitors, or aspirin) * Subject is participating in another investigational drug or device clinical trial that has not reached its primary endpoint OR subject intends to participate in another investigational drug or device clinical trial within 12 months after the index procedure * Need for ongoing long-term anticoagulation * Subject has received an organ transplant or is on a waiting list for an organ transplant * Subject is receiving or scheduled to receive chemotherapy within 30 days before or after the index procedure * Planned CABG after the index procedure * Subject previously treated at any time with intravascular brachytherapy * Subject has a platelet count \<100,000 cells/mm3 or \>700,000 cells/mm3 * Subject has a white blood cell (WBC) count \< 3,000 cells/mm3 * Subject has documented or suspected liver disease, including laboratory evidence of hepatitis * Subject has a clinically significant bleeding diathesis or coagulopathy or will refuse blood transfusions * Subject has had a history of cerebrovascular accident (CVA) or transient ischemic attack (TIA) within the past 6 months * Subject has an active peptic ulcer or active gastrointestinal (GI) bleeding * Subject has severe symptomatic heart failure (i.e., NYHA class IV) * Subject with known intention to procreate within 12 months after the index procedure (women of child-bearing potential who are sexually active must agree to use a reliable method of contraception from the time of screening through 12 months after the index procedure) * Subject is a woman who is pregnant or nursing (a pregnancy test must be performed within 7 days prior to the index procedure in women of child-bearing potential)