A meta-analysis of randomized, controlled trials of coronary CT angiography (CCTA) in the emergency department (ED) for patients presenting with chest pain found CCTA use was associated with shorter lengths of stay and decreased costs but increased invasive coronary angiography and revascularization. The findings were published Feb. 11 in the Journal of the American College of Cardiology.
Most patients who present at the ED with acute chest pain do not have acute coronary syndrome (ACS); however, such patients typically undergo numerous tests to rule out ACS or other serious conditions, leading to a prolonged length of stay. Several studies of CCTA have shown that it can quickly and accurately rule out ACS, but only recently have there been a sufficient number of such studies to conduct an analysis of post-test outcomes and downstream testing.
Edward V. Hulten, MD, MPH, of Brigham and Women’s Hospital in Boston, and colleagues reviewed four recent controlled, randomized trials of ED triage of acute chest pain to compare outcomes and downstream testing of patients who underwent CCTA and patients who received usual care. The researchers focused on incidence of invasive coronary angiography, coronary revascularization, death, nonfatal myocardial infarction (MI), repeat ED evaluations for chest pain, readmission for ACS, length of stay and cost.
The meta-analysis comprised 3,266 patients, of whom 1,869 underwent CCTA and 1,397 received usual care. The average age of the patients was 51 and 47 percent were male. The baseline characteristics of the two groups did not differ significantly.
There were no deaths and few MIs reported; therefore, the researchers could not perform a meaningful meta-analysis for these outcomes.
Patients who underwent CCTA eventually had ICA at a rate of 8.4 percent vs. 6.3 percent for patients who received usual care. After CCTA, 4.6 percent of patients underwent revascularization by PCI or CABG compared with 2.6 percent of the patients who received usual care.
Post-discharge visits to the ED with recurrent chest pain were similar between the two groups: 4.2 percent after CCTA and 4.5 percent after usual care. The researchers calculated that three ED visits per 1,000 patients were avoided through the use of CCTA.
Rates of post-discharge hospitalization for ACS were low in both groups; 1.5 percent after CCTA and 1.3 percent after usual care. The researchers calculated that there were three additional post-discharge hospitalizations for ACS for every 1,000 patients triaged with CCTA.
A pooled meta-analysis of length of stay was not possible because the four studies Hulten et al analyzed enrolled patients at different times in their hospitalization. However, the authors of the meta-analysis noted that all the studies reported significant reductions in length of stay with CCTA. For similar reasons they did not conduct a pooled analysis of costs, but explained that three of the trials reported lower costs with CCTA and one reported no difference.
CCTA to rule out CAD in low-to-intermediate-risk patients is safe, the authors concluded, citing the low rates of death, MI, return visits to the ED for chest pain and recurrent hospitalizations. The average reported length of stay was consistently lower for patients who received CCTA versus usual care, they reported.
There was a significantly higher rate of downstream invasive procedures among the patients who received CCTA, but the researchers were unable to determine whether that increase was “due to overuse of invasive coronary angiography and PCI/CABG in the CCTA group or underuse in the usual care group,” they wrote.
Explaining that CCTA is not a test that should be given to all comers who present with chest pain, the researchers noted that the study is most appropriate for low-to-intermediate-risk patients who have undergone triage using clinical and patient data. They suggested that further refinements to CCTA that will increase its ability to identify hemodynamically significant lesions might reduce the incidence of invasive procedures after CCTA.
The authors pointed out that their study results cannot be extrapolated to higher-risk patients, and they explained that the studies they analyzed did not follow identical usual care and CCTA protocols. They acknowledged that short follow up times in the studies, expert center bias and the fact that allocation to usual care or CCTA cannot be concealed as limitations to their study.