National Trends in Coronary Artery Disease Imagingassociations with Health Care Outcomes and Costs

Background: We sought to determine the impact of temporal trends and the 2016 updated National Institute for Health and Care Excellence chest pain guidelines (CG95) on imaging investigations and outcomes for coronary artery disease. Methods: Investigations for coronary artery disease from 2012-2018 were extracted from the English national database of imaging procedures and linked to national hospital admission and mortality registries. Growth rates were calculated, adjusted for population size, and linked with trends in cardiovascular hospital admissions and mortality compared across tertiles of imaging growth. The impact of CG95 was assessed using an interrupted time-series analysis. Findings: From 2012-2018, 1,909,314 investigations for coronary artery disease were performed, with an annualised per capita growth rate of 4·8%. At a national level, CG95 was associated with a rise in coronary computed tomography angiography (CTA) (exp(β) 1·10 [95% confidence interval 1·03 to 1·18], p=0·006), with no change in myocardial perfusion imaging and a potential modest fall in invasive coronary angiography (exp(β) 0·997 [0·993 to 1·00], p=0·06). At a regional level, greater CTA growth was associated with reduced hospitalisations for myocardial infarction (-0·7 [-0·8 to 1·7] admissions/100,000 population/year) whereas lower growth was associated with increased hospitalisations for myocardial infarction (1·8 [0·9 to 2·7] admissions/100,000 population/year). Cardiovascular and coronary artery disease deaths fell by -2·95 [-3·11 to -2·72] and -1·66 [-1·79 to -1·51] deaths/100,000/year respectively (p