Exercise positron emission technology (PET) imaging of the heart to predict cardiac complications after major cancer surgery

This is an observational study, investigating the feasibility and utility of preoperative exercise cardiac positron emission technology (PET) imaging in identifying patients with cardiac disease preoperatively. Participants will undergo cardiopulmonary exercise testing (as per standard institutional protocol before major cancer surgery), which involves 10-12 minutes of cycling on a stationary bicycle. Endothelial function will be assessed non-invasively using a finger tonometry device (EndoPAT) before cardiopulmonary exercise testing. This involves application of a finger-probe on each hand which measures arterial pulse wave amplitude using plethysmographic technology. The testing process involves a resting measurement phase, forearm occlusion (using a blood pressure cuff inflated above systolic blood pressure on one arm for 5 minutes), and a final measurement of the magnitude of reactive hyperaemia after release of the forearm blood flow occlusion. Exercise PET imaging involves intravenous injection of radiolabelled glucose after peak exercise through an intravenous cannula. The radiolabelled glucose is taken up by ischaemic myocardium in the fasted state after a high fat and low carbohydrate meal. PET imaging then uses detection of emitted positrons to generate a tomographic image of the heart. Patients must fast for 4-6 hours prior to the cardiopulmonary exercise test, and must consume a high fat, low carbohydrate meal for dinner the evening prior to the test and at 4-6 hours before the exercise test. A range on suggested high fat, low carbohydrate meals options will be provided to participants to choose from. The total duration of cardiopulmonary exercise testing is approximately 60 minutes. Participants will undergo PET scans 1-2 hours after the cardiopulmonary exercise test. The cardiac PET scan duration is approximately 10 minutes.