Background: Acute coronary syndrome is a common medical emergency. The optimal strategy to investigate patients who are at intermediate risk of acute coronary syndrome has not been fully determined.
Objective: To investigate the role of early computed tomography coronary angiography in the investigation and treatment of adults presenting with suspected acute coronary syndrome.
Design: A prospective, multicentre, open, parallel-group randomised controlled trial with blinded end-point adjudication.
Setting: Thirty-seven hospitals in the UK.
Participants: Adults (aged ≥ 18 years) presenting to the emergency department, acute medicine services or cardiology department with suspected or provisionally diagnosed acute coronary syndrome and at least one of the following: (1) a prior history of coronary artery disease, (2) a cardiac troponin level > 99th centile and (3) an abnormal 12-lead electrocardiogram.
Interventions: Early computed tomography coronary angiography in addition to standard care was compared with standard care alone. Participants were followed up for 1 year.
Main outcome measure: One-year all-cause death or subsequent type 1 (spontaneous) or type 4b (stent thrombosis) myocardial infarction, measured as the time to such event adjudicated by two cardiologists blinded to the computerised tomography coronary angiography ( CTCA ) arm. Cost-effectiveness was estimated as the lifetime incremental cost per quality-adjusted life-year gained.
Results: Between 23 March 2015 and 27 June 2019, 1748 participants [mean age 62 years (standard deviation 13 years), 64% male, mean Global Registry Of Acute Coronary Events score 115 (standard deviation 35)] were randomised to receive early computed tomography coronary angiography (n = 877) or standard care alone (n = 871). The primary end point occurred in 51 (5.8%) participants randomised to receive computed tomography coronary angiography and 53 (6.1%) participants randomised to receive standard care (adjusted hazard ratio 0.91, 95% confidence interval 0.62 to 1.35; p = 0.65). Computed tomography coronary angiography was associated with a reduced use of invasive coronary angiography (adjusted hazard ratio 0.81, 95% confidence interval 0.72 to 0.92; p = 0.001) but no change in coronary revascularisation (adjusted hazard ratio 1.03, 95% confidence interval 0.87 to 1.21; p = 0.76), acute coronary syndrome therapies (adjusted odds ratio 1.06, 95% confidence interval 0.85 to 1.32; p = 0.63) or preventative therapies on discharge (adjusted odds ratio 1.07, 95% confidence interval 0.87 to 1.32; p = 0.52). Early computed tomography coronary angiography was associated with longer hospitalisations (median increase 0.21 days, 95% confidence interval 0.05 to 0.40 days) and higher mean total health-care costs over 1 year (£561 more per patient) than standard care.
Limitations: The principal limitation of the trial was the slower than anticipated recruitment, leading to a revised sample size, and the requirement to compromise and accept a larger relative effect size estimate for the trial intervention.
Future work: The potential role of computed tomography coronary angiography in selected patients with a low probability of obstructive coronary artery disease (intermediate or mildly elevated level of troponin) or who have limited access to invasive cardiac catheterisation facilities needs further prospective evaluation.
Conclusions: In patients with suspected or provisionally diagnosed acute coronary syndrome, computed tomography coronary angiography did not alter overall coronary therapeutic interventions or 1-year clinical outcomes, but it did increase the length of hospital stay and health-care costs. These findings do not support the routine use of early computed tomography coronary angiography in intermediate-risk patients with acute chest pain.
Trial registration: This trial is registered as ISRCTN19102565 and Clinical Trials NCT02284191.
Funding: This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 37. See the NIHR Journals Library website for further project information.
Keywords: ACUTE CHEST PAIN; ACUTE CORONARY SYNDROME; ANGINA PECTORIS; CARDIAC CT; CHEST PAIN ASSESSMENT; COMPUTED TOMOGRAPHY; CORONARY HEART DISEASE; CT CORONARY ANGIOGRAM; EMERGENCY DEPARTMENT.
Why did we do the research?: Chest pain is a common medical emergency. It is important to decide if the cause is a heart attack. The two tests that are often used are a heart recording (electrocardiogram) and a blood test (troponin levels). If both are normal, the cause of chest pain is unlikely to be a heart attack and the patient is often discharged home. If either test is positive or if the patient has had previous heart problems, then the patient may require further investigation. We wanted to test whether or not adding a heart scan called a computerised tomography coronary angiogram improved patients’ care.
How did we do the research?: We carried out a randomised trial in which half of the patients attending hospital with chest pain had a computerised tomography coronary angiography scan as part of their assessment and half of the patients did not. In total, 1749 patients were recruited and followed up for 1 year.
Bringing it all together: The use of an additional early computerised tomography coronary angiography scan for chest pain patients of medium risk produced only small improvements in patient care.