ABC | Volume 112, Nº1, January 2019

Viewpoint Gottlieb et al CCTA takes the center stage and here is why Arq Bras Cardiol. 2019; 112(1):104-106 patients. It is particularly interesting to note that this was driven by an increase in the prevalence and certainty for the diagnosis of CAD overall, but also by an increase in certainty with a decrease in the prevalence of angina due to CAD. Those changes in diagnosis also led to meaningful changes in the management of this population. When compared to the UC arm, the addition of CCTA resulted in a changed in the use of additional testing in 15% of the population (vs. 1% in the UC), and the use of medications in 23% (vs. 5% in the UC, p < 0.001) for both. It is particularly important to dissect those changes to appropriately understand the impact of CCTA on the initial management of this population. The additional information provided by the CCTA improved diagnostic certainty both due to the increase and decrease in the likelihood of disease after a positive and negative CCTA result, respectively. Thus, for the downstream use of diagnostic testing in the UC group, upon the 6-week return visit, there were overall 6 additional stress imaging tests, 8 ICAs performed and only one ICA cancelled. On the other hand, in the UC + CCTA group there were 121 stress imaging tests, 29 ICA cancelled, 5 additional stress imaging tests and 94 ICA tests performed. Collectively, this suggests that these differences in downstream additional testing were the result of additional information provided by the CCTA. A similar pattern of change was also noted on the use of medications in both groups. In the UC there was minimal cancellation of preventive and antianginal medication (0.4% and 0.3% of patients, respectively), but a significant increase in its use (4.1% and 0.5% patients, respectively). On the other hand, a much larger shift in the use of medications was noted in the UC + CCTA arm, in both directions and both for preventive and antianginal medications. Those medications were started in 14.1% and 4.0% individuals, respectively, and stopped in 3.7% and 5.4% individuals, respectively. It is also worth noting that those results might underestimate the true changes inmanagement, as the authors did not capture changes in medication dose/intensity, nor were any documentation of changes in non-pharmacological therapy available. Importantly, the changes in revascularization did not reach statistical significance, though they were numerically more frequent in the UC + coronary CTA arm (11.2 vs. 9.7%, p = 0.06). It is important to highlight that even this extent of detail in medication change during the course of the SCOT-HEART study still overly simplifies its potential impact in event reduction. The actual change in therapy cannot be fully appreciated simple by counting the number of individuals who underwent changes in prescription without qualitative information on this population. Individuals in whom therapy was reduced were, in general, individuals with no or mild coronary atherosclerosis, whereas individuals in whom therapy was increased were individuals with more extensive and severe CAD. Thus, therapy was targeted and individuals more likely to derive benefit. Despite those changes inmanagement, the initial publication of SCOT-HEART left some gaps in the understanding of the impact of those findings, as both groups had similar improvement in the angina frequency and stability after 6 weeks, and the changes in hard outcomes did not reach formal statistical significance despite the almost 40% reduction in events noted in the study. Those results were questioned even further as the concurrent U.S. based study PROMISE, published simultaneously, showed no difference in outcomes in individuals with suspected CAD investigated with coronary CTA vs. UC, which in the U.S. was mostly based on imaging stress testing. However, several differences between the two studies justify differences in the findings, from differences in patient population, age, sex, symptoms, as well as pre-test probability of disease. Additionally, differences in medication changes during the follow up were noted. While care after testing was left at the discretion of the attending physician in both trials, SCOT-HEART had a structured protocol to recommend preventive medical therapy to individuals with non-obstructive CAD on the coronary CTA, whereas PROMISE did not make any recommendations. 10 The trend in outcomes reduction documented in SCOT‑HEART was further replicated in a meta-analysis and in a large Danish registry. 5,11 In both studies an increase in revascularization was also noted, and the Danish study also demonstrated that a concurrent increase in the use of preventive therapy (aspirin and statin) was noted. Yet, none of those results led to nearly as much repercussion on the topic as the recent publication of the 5-year follow up of the SCOT-HEART. 12 In the longer term follow up of the same cohort of patients, several important differences need to be highlighted. First, with the larger number of events, there is a higher precision on the estimates of benefit, and a 40% reduction in the rate of coronary heart disease death or myocardial infarction (p < 0.004) was now documented. A second important finding of the study is the fact that the initial increase in the rate of ICA and revascularizations was no longer seen at 5 years. While the rate of ICA was 23.6% in the UC + coronary CTA arm, it was 24.2% in the UC arm (hazard ratio: 1.00, 95% confidence interval 0.88 – 1.13). This fact occurred as the UC arm had higher rates of ICA and revascularizations after the initial evaluation. Using a landmark analysis with a starting point at 12 months, the UC+CCTA arm had a 30% reduction in the rate of ICA through 5 years and a 40% reduction in late revascularizations when compared to UC. Another relevant aspect of SCOT-HEART is that approximately half of the myocardial infarctions occurred in individuals without the obstructive coronary disease. Although it is well known that nonobstructive plaques may be responsible for a significant proportion of those events, no study had provided data on its prevalence in lower risk stable individuals until these recent CCTA studies. This finding highlights the need to incorporate the investigation of nonobstructive CAD, regardless of the presence of ischemia (and perhaps symptoms), as those findings can have significant clinical impact and should prompt pharmacological and non‑pharmacological interventions. The recent NICE guidelines from the United Kingdom delineates CCTA as a first line test for the investigation of suspected CAD, regardless of the pretest probability of disease. 13 The findings from SCOT-HEART, along with the results of Danish registry, 11 as well as cost‑effectiveness analyses 14 all support the NICE guidelines in its recommendation. Together they provide a consistent and sound body of evidence to challenge the current clinical practice recommendations. As a medical community, we 105