The goal of this clinical trial is to evaluate the feasibility of a cardiac pre-hab program for patients with blocked arteries (CTO) who are referred for PCI treatment. The main questions it aims to answer are:

Can the pre-hab program improve patients' functional capacity before PCI? Does the pre-hab program impact the need for PCI based on improvements in patients' health?

Participants will:

Undergo an initial assessment including a physical exam, medication history, quality of life questionnaires, and blood work.

Complete a 6-month cardiac rehabilitation program. Have repeat assessments to evaluate improvements and determine if PCI is still needed.

If PCI is performed, be assessed again one month later for functional capacity improvements.

If PCI is not needed after 6 months, participants will be followed virtually for an additional 5 months.

This is an investigator-initiated prospective single-arm single-center feasibility study of a cardiac pre-hab program for CTO patients referred for CTO PCI. All patients who undergo a coronary angiogram at the London Health Sciences Centre (LHSC) or who are referred to the LHSC CTO PCI program for the CTO PCI procedure within 1 year, will be screened for enrolment. Those who consent to participate in the trial will be referred to the Cardiac Rehabilitation and Secondary Prevention (CRSP) program for a period of cardiac rehabilitation (CR) prior to performing CTO PCI procedure (termed 'pre-hab'). Physical exam, prior history of medications, quality of life questionnaires and blood work will be performed at baseline during their initial pre-hab clinic consultation (Assessment 1). 6 months of pre-hab and medical optimization will be then initiated. After 6 months at Assessment 2 a repeat MIBI and functional Capacity will be reassessed and compare with baseline if there has been any improvement. Based on them, the need for CTO PCI will be redetermined. If CTO PCI is still indicated,(Assessment 3a) after one month of CTO-PCI will be performed to assess improvement in functional capacity.

On the other hand, if CTO-PCI is not required after 6 months the participant will be followed virtually by Cardiac Rehab for 5 months. A final Assessment 4 will be made at 6 month in both instances

Inclusion Criteria:

1. The presence of a chronic total occlusion in at least one major coronary artery (diameter ≥ 2.5mm).

2. Patients who have an indication for percutaneous coronary intervention of a CTO, which includes the presence of:

   1. Angina or anginal-equivalent symptoms and
   2. Ischemia or viability in the CTO territory

3. Patient aged ≥18 years of age.

Exclusion Criteria:

1. Inability or refusal to participate in the study's cardiac rehabilitation program.
2. Participation in CR program in the last 1 year.
3. Life expectancy of < 12 months due to non-cardiovascular comorbidities.
4. Anatomy deemed unsuitable for CTO PCI.
5. Severe left main disease (angiographic stenosis ≥50%; fractional flow reserve ≤0.80; minimal lumen area <6mm2).
6. Severe valvular disease or valvular disease likely to require surgery or percutaneous valve replacement during the study period.
7. Pregnancy.
8. Acute coronary syndrome within two months.
9. Canadian Cardiovascular Society Class ≥III angina of recent onset.
10. Angina of any class with a rapidly accelerating pattern.
11. Cardiac transplant recipient.
12. Inability to understand the questionnaires used in the study.
13. Patients unable to provide consent for the study.

Not part of the study plan/design.