Inclusion Criteria:
Clinical Inclusion Criteria:
1. Aged 18 years and older.
2. Subjects with coronary artery disease who have symptoms of angina pectoris and evidence of ischemia or myocardial viability in the area innervated by the coronary arteries where the CTO is located.
3. Subjects who are able to understand the purpose of the trial, participate voluntarily or by proxy and indicate by signing the informed consent form that they recognize the risks and benefits described in the informed consent document and are willing to undergo clinical follow-up.
Angiography Inclusion Criteria:
1. There is only one target CTO that needs to be treated with percutaneous coronary intervention (PCI).
2. Target CTO is located in a native coronary artery with a reference vessel diameter of ≥ 2.5 mm.
3. Angiography showed complete occlusion of the target CTO (visual inspection), antegrade flow of the occluded vessel segment TIMI grade 0 and inferred occlusion time ≥ 3 months; or previous angiographic records confirmed occluded time of the target CTO ≥ 3 months.
4. The target CTO occluded segment length ≥ 5 mm (visual inspection).
5. Angiography of the target CTO showed high density along the vessel, which is considered calcified lesion.
6. The antegrade approach is determined as the primary strategy with guidewire crossing in PCI treatment.
7. The fibrous cap of the target lesion can not be penetrated within 60 seconds using the guidewire with polypolymer coated or tip stiffness \> 1.5g (visual inspection) under fluoroscopy and the time is timed when the guidewire reaches the fibrous cap. (To identify chronic total occlusions and exclude acute or subacute occlusions that such guidewire can pass directly).
8. In addition to the target lesion, there must be up to one non-target lesion to be treated and it is located on a different epicardial vessel than the target lesion. Target lesions can be treated after successful treatment of the non-target lesion (residual stenosis \< 30% and TIMI 3 flow) without complications.
Exclusion Criteria:
General Exclusion Criteria:
1. Acute myocardial infarction within 30 days prior to baseline procedure.
2. Life expectancy \< 1 year.
3. Inability to use protocol-required concomitant medications (eg, aspirin, P2Y12 platelet receptor inhibitors, heparin, contrast agents, etc) due to allergy or other contraindications, and no alternative medications.
4. The target CTO has an iatrogenic dissection that occurred within the past 3 months.
5. Left ventricular ejection fraction less than 35%.
6. Severe aortic or mitral valve disease.
7. Planned left ventricular (LV) support device during CTO PCI.
8. Subjects with clear bleeding tendency, contraindications to antiplatelet agents and anticoagulant therapy.
9. Stroke, transient ischemic attack (TIA), or significant gastrointestinal (GI) bleeding within 6 months before the baseline procedure.
10. Planned additional coronary or valvular percutaneous or surgical intervention scheduled within 30 days after baseline procedure.
11. Subjects who require emergent or urgent PCI.
12. Female subjects who are pregnant or breast-feeding.
13. Subjects who are participating in another investigational drug or device clinical trial in which the primary endpoint is still not reached, or intend to participate in another investigational drug or device clinical trial within 12 months after baseline procedure.
14. Other medical illnesses that may cause the subject to be non-compliant with the protocol or confound data interpretation.
15. Serum creatinine \> 2.5 mg/dL (or 221 µmol/L), or on dialysis.
16. Hemodynamic instability or severely impaired activity tolerance (KILLIP Class III, IV, or NYHA Class III, IV).
17. Subjects with sustained tachyarrhythmia or cardiogenic shock.
Angiography Exclusion Criteria:
1. The target CTO is in an unprotected left main.
2. No angiographically visible collateral flow to the target vessel distal to the occlusion, from ipsilateral or contralateral collaterals.
3. Because of the presence of moderate to severe tortuosity or stenosis in the collateral vessels, retrograde approach is not preferred at the investigator 's discretion.
4. Vessel tortuosity proximal to, or within, body of target occlusion which, in the opinion of the investigator, is not amenable to advancement of a microcatheter or Coronary Crossing System.
