OBJECTIVES: An urgent transition to environmentally sustainable healthcare is required. The purpose of this study was to identified key areas for environmental impact mitigation for a coronary artery bypass grafting trajectory. METHODS: An ISO14040/44-standardised life cycle assessment was conducted for the functional unit of an individual patient trajectory of elective coronary artery bypass grafting surgery, from operating room admission until intensive care unit discharge. Data were collected for products, processes, and services required for care delivery in a Dutch academic hospital for 12 patients. The environmental impact was calculated using the ReCiPe 2016 method. RESULTS: A single patient trajectory caused 414 [IQR 383-461] kg CO2 equivalents of global warming, equal to 2,753km of driving an average Dutch petrol-fuelled car. Other notable environmental impacts were fine particulate matter, (non-)carcinogenic toxicity, land use, and terrestrial acidification. Operating room disposable products (162 kgCO2eq), energy use (48 kgCO2eq), and employee commute (36 kgCO2eq) contributed most to global warming. The extracorporeal circulation set, surgical drapes, intraoperative salvage set, surgical gowns, and cotton gauzes caused most of the disposables' environmental impact. Most energy use occurred in the operating room via heating, ventilation, and air conditioning. CONCLUSIONS: A coronary artery bypass grafting trajectory's environmental impact primarily contributed to global warming. Most impact mitigation could be achieved by avoiding/reducing disposable product use when possible, or replacing these with reusables. Optimising operating room energy systems, switching to renewable energy, and encouraging low-emission employee commute can further reduce the environmental impact.