What this Trial Is About

A Chronic Total Occlusion or CTO of a coronary artery is a an artery that has been blocked for \>/= 3 months. More than a decade ago, patients with such coronary artery blockage would have been sent for Coronary Artery Bypass Graft (CABG) surgery. Newer tools and techniques have facilitated the opening (angioplasty or percutaneous coronary intervention (PCI)) of such occluded arteries- however success is not 100% unlike in simple coronary blockages. Computed Tomography Coronary Angiography (CTCA) identifies the artery path and characteristics of the CTO including calcification - the latter many times is the reason for failure to cross the CTO. The investigators aim to conduct a feasibility study to assess the effectiveness of CTCA prior to CTO PCI by randomizing suitable CTO patients to CTCA or direct CTO PCI. 20 patients will be randomized 1:1 using the sealed envelope technique and compared for: Primary endpoint: CTO PCI success rate in CTCA arm versus no CTCA arm Secondary endpoints: i. Angina by the Seattle Angina Questionnaire (SAQ) at 6 months (range 0-100, lower score worse, higher scores better, based on 5 characteristics - severity, frequency, treatment satisfaction and quality of life scores). ii. Compare the number of patients who required a second CTO PCI procedure in the CTCA arm versus no CTCA arm iii. Procedural differences between the intervention CTCA arm versus no CTCA arm including: Health Economics: Cost saved per patient due to improved success and reduction in readmission or further procedure CTO PCI efficiency: Wire crossing time, Procedure time CTO PCI safety outcomes: Procedural complications (Ellis perforation, tamponade, acute kidney injury/contrast induced nephropathy, access site bleeding, donor vessel injury), Radiation: CTCA dose, CTO PCI dose, and combined CTCA and CTO PCI dose. Contrast: CTCA volume, CTO PCI volume, and combined CTCA and CTO PCI volume Change in CTO PCI strategy hierarchy as a result of the CTCA review Patients will have a telephonic follow up at 6 months to assess angina ( by the Seattle Angina Questionnaire)

CT Coronary Angiography Prior to CTO PCI