Scottish Computed Tomography of the HEART - SCOT-HEART

Contribution To Literature:

The SCOT-HEART trial showed that coronary CTA is an alternative to standard care in the evaluation of low- to intermediate-risk patients with chest pain.

Description:

The goal of the trial was to evaluate coronary computed tomography angiography (CTA) compared with standard care among low- to intermediate-risk patients with chest pain suggestive of obstructive coronary disease.

Study Design

  • Parallel
  • Randomized

Low- to intermediate-risk patients with chest pain were randomized to evaluation with coronary CTA (n = 2,073) versus standard care (n = 2,073).

Patient population:

  • Total number of enrollees: 4,146
  • Duration of follow-up: median 1.7 years
  • Mean patient age: 57 years
  • Percentage female: 44%
  • Percentage diabetics: 11%
  • Baseline exercise electrocardiography (ECG) was performed in 85% of subjects in both groups (abnormal in 15% of subjects in both groups)
  • Subsequent stress imaging was performed in 9% of the coronary CTA group vs. 10% of the standard care group
  • Median radiation dose = 4.1 mSv

Inclusion criteria:

  • Patients 18-75 years of age with chest pain suggestive of coronary disease

Exclusion criteria:

  • Inability to undergo coronary CTA
  • Renal failure
  • Contrast allergy
  • Pregnancy
  • Acute coronary syndrome within last 3 months

Principal Findings:

Primary diagnostic outcomes:

  • CTA increased certainty in the diagnosis of angina due to coronary heart disease (CHD) (relative risk [RR] = 1.79, 95% confidence interval [CI] 1.62-1.96, p < 0.001) vs. standard care
  • CTA reduced frequency of the diagnosis of angina due to CHD (RR = 0.93, 95% CI 0.85-1.02, p = 0.13) vs. standard care

Primary clinical outcome:

  • CHD death or nonfatal myocardial infarction (MI) at 5 years: 2.3% in the CTA group vs. 3.9% in the standard care group (p = 0.004)

Secondary outcomes:

  • Short-term coronary revascularization: 11.2% vs. 9.7% (p = 0.061), respectively, for CTA vs. standard care
  • Short-term CHD death or MI: 1.3% vs. 2.0% (p = 0.053), respectively, for CTA vs. standard care
  • Change in physical limitation at 6 months: 1.6 vs. 3.0 (p = 0.03), respectively, for CTA vs. standard care
  • Change in angina stability at 6 months: 13.4 vs. 12.5 (p = 0.1), respectively, for CTA vs. standard care
  • Change in angina frequency at 6 months: 18.3 vs. 19.2 (p = 0.02), respectively, for CTA vs. standard care
  • Change in treatment satisfaction at 6 months: -5.0 vs. -4.3 (p = 0.1), respectively, for CTA vs. standard care
  • Change in quality of life at 6 months: 15.5 vs. 18.6 (p < 0.0001), respectively, for CTA vs. standard care
  • Nonfatal MI at 5 years: 2.1% in the CTA group vs. 3.5% in the standard care group (p = 0.007)
  • Invasive angiography at 5 years: 23.7% in the CTA group vs. 24.2% in the standard care group (p = 0.99)
  • Coronary revascularization at 5 years: 13.5% in the CTA group vs. 12.9% in the standard care group (p = 0.41)

Interpretation:

Among low- to intermediate-risk patients with chest pain, coronary CTA increased the certainty of the diagnosis of angina due to CHD. This definition of angina considered a ‘yes’ or ‘no’ diagnosis, compared with a ‘probable’ or ‘unlikely’ diagnosis. This definition is more patient-centric by definitely ruling in or ruling out disease.

On the other hand, coronary CTA appeared to reduce the frequency of the diagnosis of angina due to CHD. This definition of angina considered a ‘yes’ or ‘probable’ diagnosis, compared with an ‘unlikely’ or ‘no’ diagnosis. This definition is more physician-centric by increasing diagnosis sensitivity, which gives an enhanced opportunity to treat the underlying disease. Coronary CTA was associated with smaller improvements in angina symptoms and quality of life compared with standard care.

Coronary CTA compared with standard care was associated with a nonsignificant increase in coronary revascularization procedures and a nonsignificant reduction in CHD death or MI in the short-term. At a median follow-up of nearly 5 years, CTA was associated with a reduction in CHD death or MI vs. standard care. Benefit was largely due to a reduction in nonfatal MI. Although CTA was associated with an increase in invasive therapy and revascularization in the short-term, there was no difference in invasive therapy and revascularization between treatment arms at 5 years. Since there was no difference in overall revascularization rates, long-term benefit from CTA may have been due to lifestyle modification and statin therapy. SCOT-HEART (and PROMISE) shows that coronary CTA is an alternative to standard care (including conventional stress testing) in the evaluation of patients with chest pain.

References:

The SCOT-HEART Investigators. Coronary CT Angiography and 5-Year Risk of Myocardial Infarction. N Engl J Med 2018;379:924-33.

Presented by Dr. David Newby at the European Society of Cardiology Congress, Munich, Germany, August 25, 2018.

Williams MC, Hunter A, Shah A, et al., on behalf of the Scottish COmputed Tomography of the HEART (SCOT-HEART) Trial Investigators. Symptoms and quality of life in patients with suspected angina undergoing CT coronary angiography: a randomised controlled trial. Heart 2017;103:995-1001.  

The SCOT-HEART Investigators. CT coronary angiography in patients with suspected angina due to coronary heart disease (SCOT-HEART): an open-label, parallel-group, multicentre trial. Lancet 2015;385:2383-91.

Editorial Comment: Douglas PS. The theory and practice of imaging outcomes research. Lancet 2015;385:2334-5.

Presented by Dr. David E. Newby at ACC.15, San Diego, CA, March 15, 2015.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Computed Tomography, Nuclear Imaging

Keywords: ACC Annual Scientific Session, Angina Pectoris, Coronary Angiography, Coronary Artery Disease, Coronary Disease, Electrocardiography, Tomography, X-Ray Computed, Chest Pain, Myocardial Infarction, Risk Factors, Prospective Studies


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