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Three Part Question

In [low-to-intermediate-risk patients presenting with possible acute coronary syndromes] is [coronary CT angiography compared to current standard of care] safe for [discharge of patients from the Emergency Department]?

Clinical Scenario

A 45yo male without significant medical problems presents to the Emergency Department complaining of acute onset of chest pain. His initial EKG and troponins are within normal limits. The department is over-crowded as usual, and you contemplate whether coronary CT angiography would be a reasonable safe way to exclude ACS and discharge the patient from the department.

Search Strategy

Medline 1996-04/13 using OVID interface, Cochrane Library (2013), PubMed clinical queries
[(exp tomography, x-ray computed) AND (exp cardiac imaging techniques)] Limit to English language and randomized controlled trial

Search Outcome

133 papers were identified; including four randomized, controlled trials that were relevant to the clinical question. All four trials were summarized in a single systematic review published in 2013.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Hulten E, Pickett C, Bittencourt MS, Villines TC, Petrillo S, Di Carli MF, Blankenstein R Feb 26 2013 USA	1,869 adult patients with acute chest pain undergoing CCTA and 1,397 undergoing usual care.	Systematic review and meta-analysis of randomized, controlled trials	Death	No deaths occurred in either group	The patient evaluation according to usual care was not consistent across all four studies included in the meta-analysis. Protocols after CCTA imaging were also not consistent across the studies. Although the majority of complications occurred during index hospitalization, the length of follow-up varied from 1-6 months between studies included. There were not enough patients in the study to power the outcome evaluations for myocardial infarction and death. It was not possible to blind participants to intervention arms based on the nature of the evaluations.
			Nonfatal myocardial infarction	2.1% in the usual care group, 1.1% in the CCTA group (OR 0.54)
			Invasive coronary angiography	6.3% in the usual care group, 8.4% in the CCTA group (OR 1.36)
			Revascularization	2.6% in the usual care group, 4.6% in the CCTA group (OR 1.81)
			Post-discharge ED visits for recurrent chest pain	4.5% after usual care, 4.2% after CCTA (OR 0.94)
			Post-discharge hospitalizations for ACS	1.3% after usual care, 1.5% after CCTA (OR 1.2)
			LOS and Cost assessment	Three studies reported cost savings with CCTA, 1 reported no difference; all studies reported a reduction in LOS in the CCTA group using differing parameters (e.g. total hospital stay versus ED stay)

Comment(s)

This meta-analysis includes the largest number of patients to date on the use of CCTA to determine safety for discharge from the Emergency Department, however, there is insufficient evidence to power the major outcomes of death or myocardial infarction. That said, rates remain low with both usual care and CCTA groups. Revascularization rates were higher in the CCTA groups, and further study will need to determine the appropriateness of these interventions that would not have been detected with traditional means.

Clinical Bottom Line

For low-to-intermediate risk patients with acute chest pain, CCTA is probably a reasonable means of determining discharge from the Emergency Department, but further study is needed. CCTA compared to usual care does result in decreased cost and length of stay, but higher rates of intervention and revascularization.

References

1. Hulten E, Pickett C, Bittencourt MS, Villines TC, Petrillo S, Di Carli MF, Blankenstein R Outcomes after coronary computed tomography angiography in the Emergency Department: a systematic review and meta-anaylsis of randomized, controlled trials. J Am Coll Cardiol 2013 Feb 26;61(8):880-92