Prognostic value of fractional flow reserve from computed tomography

Coronary artery disease remains the leading cause of death around the world, even during the COVID-19 pandemic, and it is therefore essential that we continue our quest to improve the prevention, diagnosis, management and outcome of coronary artery disease. Fifty years ago, in 1971, the first CT scan was performed on a machine invented by Sir Godfrey Hounsfield who, even in those early days, realised the potential of CT to assess the heart and coronary arteries.1 Technological advances mean that it is now possible to obtain extensive information on the presence, severity and characteristics of atherosclerotic plaque from coronary CT angiography (CCTA). In addition, it is also possible to use computational modelling to obtain an estimate of fractional flow reserve from static CCTA images (FFRCT). CCTA now plays a central role in the assessment and management of patients with symptoms of suspected coronary artery disease in both national and international guidelines. However, the role of FFRCT in clinical practice is less certain. Norgaard et al 2 present a meta-analysis of the prognostic information provided by FFRCT from a single vendor (HeartFlow) in 5460 patients from 5 observational studies and registries. Coronary artery disease was prevalent in the population, with 72% having at least one stenosis >50% on CCTA and 61% having a positive FFRCT of ≤0.80. Overall event rates were low, with myocardial infarction or all-cause mortality occurring in 0.6% of FFRCT negative patients and 1.4% of FFRCT positive patients. Patients with FFRCT ≤0.80 were threefold more likely to experience myocardial infarction, unplanned coronary revascularisation and major adverse cardiac events, although there was no demonstrable difference in all-cause mortality. In addition, lower FFR …