In the Emergency Department, that is, at least.
A few years ago, there were several major studies evaluating the safety of a CT coronary angiogram-based study for the evaluation of chest pain in the Emergency Department. These studies consistently found the CTCA is sensitive for coronary artery plaque – and, thus, patients with troponin-negative chest pain syndromes and clear coronary arteries could be discharged from the ED.
The constant challenge, however, has been specificity – not only with respect to whether the CT can accurately detect stenoses, but the clinical relevance of the stenoses. Non-obstructive, moderate, and high-grade stenoses detected on CTCA all trigger further evaluation – either non-invasive or invasive, with subsequent interventions of uncertain clinical value.
This small propensity-matched study from a cohort of 25,251 patients undergoing CTCA picked out 234 pairs of patients, matching those who had an acute coronary syndrome during follow-up with those who did not. And, yes, those with ≥50% or ≥70% stenosis were more likely to suffer an ACS, but not my much. The vast majority – 62% – of those with an ACS in follow-up had non-obstructive coronary disease. Indeed, just over half of patients with an ACS even had their culprit lesion identified on the initial CTCA. The degree of stenosis was mildly predictive of future ACS, but plaque burden between those who suffered an event and those who did not was similar. The most predictive feature, however, was composition of non-obstructive plaque, including fibrofatty features and necrotic core.
This is why CTCA is unhelpful in the Emergency Department. It does, yes, accurately detect patients without coronary disease – but this target “low-risk” population already has such a low pretest likelihood of poor outcome the added value is nil. Then, the “true positives” from these studies – stenoses and interventions – are not equivalent to ACS prevented.
Friends don’t let friends do CTCA in the ED – it doesn’t add value or prevent adverse outcomes.
“Coronary Atherosclerotic Precursors of Acute Coronary Syndromes”
http://www.onlinejacc.org/content/71/22/2511
The author’s perspective deliberately ignores the wealth of RCTs over the past decade demonstrating added value of CCTA in the ED, including cost savings, ED decompression, reduced MACE (particularly MI), as well as improved patient satisfaction and lower ED recidivism.
Traditional pre-test screeening tools & risk scores fail to identify patients in the ED who will have acute MI. Hence the absolute number of MIs among “low risk” and “intermediate risk” patients ( considered suitable candidates for CCTA) is comparable, if not greater than, patients considered “high risk.” CCTA by virtue of its nearly 100% sensitivity can safely exclude coronary disease in this population, allowing ED physicians to safely discharge patients in a timely manner (instead of boarding them overnight in observation units).
All hospital systems should consider CCTA for rapid chest pain triage in appropriately selected patients if they have interest in cost savings, ED decompression & improving patient outcomes.
This author appreciates the misuse of CCTA in the ED over the past decade, including the findings of multiple sponsored trials. Adding CCTA to usual care improves on usual care – only when usual care is the low-value, inefficient care typified by our current healthcare culture. See Rita Redberg’s editorial in the NEJM, if you prefer a more prominent “name” with a similar viewpoint: https://www.nejm.org/doi/pdf/10.1056/NEJMe1206040
Your argument is based on the false premise patients need to board overnight in an observation unit to effectively rule-out AMI. There are hordes of of accelerated rule-out strategies, based on combinations of risk-stratification and timed troponin assays, and protocols can be designed to discharge any permutation of a percentage of patients with chest pain as your risk-tolerance allows. Low-risk chest pain should routinely be managed and followed as an outpatient, not in the Emergency Department or the hospital – and even intermediate- or high-risk chest pain, with appropriate care coordination: https://www.acepnow.com/article/safe-discharge-in-non-low-risk-chest-pain-patients/
CCTA is a reasonable test, appropriately applied. It should not be routinely used in the ED, and particularly not in those with low-risk chest pain.