Table 1.

Inclusion Criteria.

Inclusion Criteria

1.Accepted for CTO PCI procedure by a specialist CTO operator.

2. Patients with symptoms related to a single vessel CTO (≥3 months duration, or probable CTO where duration is unknown) in a vessel of at least 2.5mm diameter without angiographically significant (LMS ≥50%, LAD/Cx/RCA/Graft ≥70%, ≥2mm diameter) coronary artery stenosis in remaining non-CTO vessels. Symptoms are: a) Typical exertional angina defined as: i) constricting discomfort in the front of the chest or the neck, jaw, shoulder or arm ii) precipitated by physical exertion iii) relieved by rest or nitrates within 5 minutes b) Angina symptoms at rest (including decubitus angina and post-prandial angina). c) Shortness of breath on exertion considered to be angina equivalent.

3.Clinical evidence of ischaemia in CTO territory on dobutamine stress echocardiography, nuclear myocardial perfusion scan, stress perfusion cardiovascular magnetic resonance (CMR) or positron emission tomography (PET). 4.Evidence of viability: If left ventricular angiogram or echocardiogram demonstrates left ventricular (LV) impairment or regional wall motion abnormality (RWMA) then viability must be demonstrated.

5.J-CTO score ≤3.