This study is a single centre pilot for a randomized trial comparing all-blood cardioplegia to more dilute 4:1 blood cardioplegia during cardiac surgery. The hypothesis is that all-blood cardioplegia will be associated with less blood transfusion and better cardiac function.

This is a single centre randomized, double blind, 2 arm, parallel group pilot study comparing all-blood cardioplegia to 4:1 blood cardioplegia in patients undergoing cardiac surgery. This pilot study will support the design of a larger multicentre trial.

Subjects undergoing cardiac surgery will be randomized to receive either standard of care (4:1) or all-blood cardioplegia for myocardial protection. Neither of these cardioplegia approaches would be considered investigational. Each is in use at numerous cardiac surgical centres around the world. The cardioplegia will be delivered using the Quest medical MPS system which is a Health Canada Approved device.

Clinical endpoints will be evalauted (rate of blood transtransfusion, ICU stay, etc…). In a subset of subjects who meet specific criteria, ventricular function will be evaluated in the operating room using the CD Leycom INCA conductance catheter system.

Inclusion Criteria:

• patients (male and female) undergoing isolated coronary artery bypass grafting,
• isolated aortic or mitral repair or replacement, and
• combined aortic or mitral valve repair or replacement and
• coronary bypass grafting

Exclusion Criteria:

• reoperation,
• endocarditis,
• dialysis dependant renal failure,
• pre-operative ECMO or LVAD support,
• contraindication to blood transfusion (ie. Jehovah's Witness), and
• use of irreversible anti-platelet (other than ASA) and anticoagulant agents within 48h (ie. plavix, dabigitran, GpIIb/IIIa inhibitors, argatroban).