Elective percutaneous coronary intervention (PCI) is often associated with myocardial necrosis evidenced by peri-procedural troponin release. This is a surrogate for subsequent cardiovascular events. There is no study on the effect of peri-PCI oxygenation in in myocardial protection and cardiopulmonary fitness outcome. Patients with higher baseline cardiopulmonary fitness will have lower mortality.

This study is to assess the utility of oxygen to reduce ischaemia in patients with significant stable coronary artery disease scheduled for elective PCI. The secondary objective is to evaluate further effect of peri- PCI oxygenation on cardiovascular fitness and autonomic response.

OBJECTIVE: This study is to assess the utility of oxygen to reduce ischaemia in patients with significant stable coronary artery disease scheduled for elective PCI. The secondary objective is to evaluate further effect of peri- PCI oxygenation on cardiovascular fitness and autonomic response.

STUDY DESIGN: Randomized double blinded prospective pilot study SAMPLE SIZE: 30 patients scheduled for elective for PCI randomized to 2 groups, oxygen group ( 15L/min) and air group METHOD: Patient whom fulfil inclusion criteria were recruited and randomized to 2 groups via computer allocation system. The assigned inhaled gas will be delivered via high-flow mask at 15L/min for a minimum of 30 minutes immediately prior to and continued throughout the PCI procedure. Patients were blinded throughout the procedure but the practising cardiologist and staff nurses were not blinded. Routine care continued post PCI. Blood sampling for Troponin I was taken at 6 hours and 24 hours following stent implantation. Patients were discharged one day after the procedure as per current routine practice.

Patients were given routine follow up with the cardiac rehabilitation clinic in 4 weeks time post discharge. EST was arranged 6 weeks post procedure PRIMARY OUTCOME MEASURE: Troponin I at 6 and 24 hours SECONDARY OUTCOME MEASURE: METs, Heart Rate Recovery, Chronotropic Index

Inclusion Criteria:

• Patients aged >18 years
• Haemodynamically important coronary artery disease (>70% luminal stenosis angiographically in ≥1 major epicardial coronary artery

Exclusion Criteria:

• Significant chronic airways disease with type-2 respiratory failure precluding safe use of oxygen
• Coronary stenoses where evidence of plaque instability is evident e.g. rest pain, visual evidence of thrombus, elevation of Troponin T at baseline

Both medical air and oxygen were supplied in compressed liquid form and available throughout the hospital. During the study, the medical gas cylinders shielded using an opaque temporary cover. Similarly the oxygen saturation was not displayed, but instead monitored by an independent third party.