For patients with suspected acute coronary syndromes (ACS) CT angiography (CTA) compared to standard treatment can reduce the time in the emergency department (ED), according to results of the ROMICAT-II (Rule Out Myocardial Infarction/Ischemia Using Computer-Assisted Tomography) trial published in the New England Journal of Medicine. However, CTA resulted in more tests being performed and increased radiation exposure.
1000 patients with possible ACS but without ECG signs of ischemia or a positive troponin test were randomized to either CTA or standard treatment. The primary endpoint of the study, the mean length of hospital stay, was reduced from 30.8 hours in the standard evaluation group to 23.2 hours in the CTA group, a highly significant reduction of 7.6 hours (p<<0.001). In addition, many more patients in the CTA group were discharged directly from the ED (47% vs 12%, P<0.001). There were no cases of undetected ACS in either group and very few major adverse cardiovascular events (2 vs 6, p=0.18). Half of the patients in the CTA group were discharged within 8.6 hours, compared with only 10% of the controls.
ED and hospital costs were similar in both groups. Radiation exposure was increased in the CTA group (13.9 mSv vs 4.7 mSv) and more diagnostic tests were performed in the CTA group.
The authors concluded that their “data should allow providers and patients to make informed decisions about the use of this technology as an option for evaluation when symptoms are suggestive of an acute coronary syndrome.”
In contrast to the neutral presentation of the authors in the NEJM paper, strikingly different positions about the utility of CT angiography were taken in an accompanying editorial by Rita Redberg and a press release issued by the National Heart Lung and Blood Institute, which sponsored the study.
In her editorial, Redberg writes:
Although shorter lengths of stay in the hospital are highly desirable, especially from the patient’s point of view, the ROMICAT-II study reveals a deeper flaw in the approach to chest pain in the emergency department. The underlying assumption… is that some diagnostic test must be performed before discharging these low-to-intermediate-risk patients from the emergency department. This assumption is unproven and probably unwarranted. The rationale for any test, as compared with no testing, should be that it will lead to an improved outcome, and here there is no evidence that the tests performed led to improved outcomes.
Redberg points out that the very low (under 1%) rate of patients who actually had an MI in the study means “that it is impossible to know whether the CCTA groups received any benefit whatsoever.” Further, factoring in radiation doses both from CTA and nuclear stress tests and adverse reactions to contrast dye, “clinicians may legitimately ask whether the tests did more harm than good.”
For patients like those in ROMICAT II, with normal ECG findings and negative troponin tests, “multiple studies show no evidence that any additional testing further reduces that risk.”Although CTA can reduce length of stay in the hospital compared to standard care, “it is even faster to discharge these patients without any additional diagnostic test after determining that their ECG findings and troponin levels are normal.” She concludes:
In short, the question is not which test leads to faster discharge of patients from the emergency department, but whether a test is needed at all.”
By contrast, the NHLBI press release focuses exclusively on the benefits of CTA and lacks any significant discussion of its potential limitations, as presented in the NEJM paper and as discussed in detail by Redberg. The press release quotes Susan Shurin, the acting director of the NHLBI:
Identifying the underlying cause of chest pain more quickly with CT scans could allow medical care providers to better allocate limited resources to the patients who are most in need of treatment.
The principal investigator of the study, Udo Hoffmann, says that ROMICAT II can “help health care providers and patients make better informed decisions by knowing the risks and potential benefits of using CT scans to more quickly diagnose acute coronary syndrome,” but he glosses over the risks and then focuses on the benefits:
“It can be a relief to patients with chest pain to quickly know they are not having a heart attack and that they can spend the night at home, instead of in a hospital bed.”
Finally, the press release gives short shrift to the radiation issue:
Participants in the CT group were exposed to more radiation than those in the standard screening group, though the study authors suggested that future CT scans could be done using less radiation, which could help lower exposure without sacrificing accuracy.
Click here to read the NHLBI press release…