The findings suggest that CCTA is an effective alternative to other modes of assessing CAD, such as invasive coronary angiography, wrote a team led by Dr. Jonathan Weir-McCall, PhD, associate professor of radiology at University of Cambridge School of Clinical Medicine, U.K.

"[Our study shows that] greater regional increases in [the use of] CCTA were associated with fewer hospitalizations for myocardial infarction and a more rapid decline in CAD mortality," the group explained.

In 2016, the U.K.'s National Institute for Health and Care Excellence (NICE) issued an updated guidance for caring for patients with recent-onset chest pain, recommending CCTA as the initial diagnostic tool, the authors noted.

"[NICE] selected CCTA as the first-line test for those with possible angina and no known prior coronary artery disease due to its lower overall pathway costs and high sensitivity and negative predictive value," they wrote.

Weir-McCall and colleagues sought to assess the impact of this guidance on CAD outcomes through a study that consisted of data collected between 2012 and 2018 from a national U.K. database and hospital admission/mortality registries. The group adjusted imaging use rates for population size, modality, cardiovascular hospital admissions, and mortality; the study included information from 1.9 million CAD assessments. The annual per capita growth rate for these assessments was 4.8%, while annual costs were approximately 350 million pounds (395 million euros) per 100,000 patients.

Through the study time frame, invasive coronary angiography was the most common imaging exam performed, with an average of 214 angiograms per 100,000 patients with suspected CAD per year and an annual growth rate of 5.3%. SPECT was the second most common exam, with an annual average of 152 exams per year per 100,000 patients, but it had an annual growth rate decline of 4.9%. CCTA was the third most common CAD evaluation exam, at 85 exams per year per 100,000 patients, but it had the highest annual growth rate, at 15.7%.

The team found the following changes in annual growth rate by imaging exam type after the 2016 NICE guidance.

The results offer a macro view of the use of various imaging modalities to diagnose CAD, according to Weir-McCall and colleagues.

"The current study reveals several major novel and impactful findings," they concluded. "In particular, there was an increased use of CCTA, with modest reductions in invasive coronary angiography. Importantly, regions with the greatest growth in the usage of CCTA were also those that saw the greatest decline in cardiovascular mortality, with a trend toward a greater fall in all-cause mortality."