Routine outpatient computed tomographic coronary angiography (CTCA) may not reduce subsequent myocardial infarction or mortality from cardiovascular causes compared with standard care among patients with suspected acute coronary syndrome whose initial evaluation ruled out myocardial infarction.
In the multicenter, open-label TARGET-CTCA trial, researchers enrolled 3,170 patients at 14 hospitals between September 2019 and May 2023. Eligible patients had suspected acute coronary syndrome, myocardial infarction ruled out, and intermediate cardiovascular risk based on high-sensitivity cardiac troponin concentrations. Investigators randomly assigned 1,587 patients to CTCA-guided care and 1,583 to standard care. The median follow-up was 3 years.
The primary outcome was a composite of myocardial infarction or mortality from cardiovascular causes. Secondary outcomes included individual cardiovascular events, all-cause mortality, repeat hospital visits for suspected acute coronary syndrome, coronary revascularization, and major bleeding. The researchers assessed preventive medication use and subsequent cardiac investigations.
During follow-up, the primary outcome occurred in 112 patients (7%) assigned to CTCA-guided care and 116 (7%) receiving standard care, with no statistically significant difference between groups.
Myocardial infarction occurred in 93 patients (6%) in the CTCA group vs. 100 (6%) in the standard-care group. Mortality from cardiovascular causes occurred in 23 patients (1%) vs. 27 (2%), respectively. All-cause mortality was lower in the CTCA group, occurring in 73 patients (5%) vs. 97 (6%) receiving standard care. Mortality from noncardiovascular causes accounted for much of this difference, occurring in 41 patients (3%) vs. 64 (4%).
However, the secondary analyses were not adjusted for multiple comparisons, limiting interpretation of the observed mortality differences.
Among patients assigned to CTCA-guided care, 1,462 (92%) underwent imaging at a median of 22 days following randomization. Normal coronary arteries were identified in 465 patients (32%), nonobstructive coronary artery disease in 622 (43%), and obstructive disease in 331 (23%).
Imaging findings informed recommendations for preventive treatment and further cardiovascular evaluation. At 90 days, 63% of patients in the CTCA group were receiving statins vs. 49% in the standard-care group. Antiplatelet use was also higher, at 42% vs. 33%.
By the end of follow-up, statin use remained higher in the CTCA group (69% vs. 56%). Coronary revascularization had been performed in 98 patients (6%) vs. 77 (5%), respectively.
Despite these differences in clinical management, CTCA-guided care did not significantly reduce subsequent myocardial infarction or cardiovascular mortality.
The primary findings were consistent across prespecified subgroups defined by age, sex, previous coronary artery disease, preventive medication use, and troponin concentration.
An analysis stratified by the HEART score suggested a possible benefit among patients with low-risk scores. The primary outcome occurred in 22 patients (3%) assigned to CTCA-guided care vs. 39 (5%) receiving standard care.
Among patients with intermediate- or high-risk HEART scores, the primary outcome occurred in 88 patients (11%) vs. 76 (10%), respectively. The researchers found no evidence of greater benefit among patients with higher HEART scores. Subgroup findings warrant caution because of multiple comparisons.
CTCA-related adverse events occurred in 7 patients (0.4%) and included contrast-related allergic reactions and acute kidney injury. Three events were classified as serious, although symptoms were mild and resolved without intervention or following antihistamine treatment.
The incidence of primary-outcome events was lower than initially anticipated, prompting additional enrollment and extended follow-up. Although the trial accrued more events than originally planned, the findings remained compatible with both a reduction and an increase in cardiovascular risk.
About half of participants met intermediate- or high-risk criteria according to HEART scores, despite meeting the troponin-based eligibility criteria. Most participants were men, and some had established coronary artery disease or were already receiving preventive treatment, potentially limiting the additional benefit of imaging.
The trial was conducted exclusively in the United Kingdom, where coronary imaging is used relatively infrequently in routine care, which may affect the applicability of the findings to other health care systems.
“[T]he use of CT coronary angiography to guide treatment in patients with suspected acute coronary syndrome in whom myocardial infarction was ruled out did not reduce the incidence of subsequent myocardial infarction or death from a cardiac cause,” wrote lead study author Kuan Ken Lee, MD, PhD, of the University of Edinburgh, and colleagues.
Full disclosures of the study authors can be found in the study.
Source: New England Journal of Medicine
