Triple Rule Out vs. Coronary CT Angiography in Chest Pain
How do the diagnostic yields of triple rule out (TRO) and computed tomography angiography (CTA) compare among patients evaluated for acute chest pain?
The Advanced Cardiovascular Imaging Consortium (ACIC) included patients at 53 Michigan institutions who underwent TRO or coronary CTA for acute chest pain (in the emergency department or inpatient setting). Demographic characteristics, scan findings, and image quality parameters were compared between coronary CTA and TRO scans. The primary outcome was diagnostic yield, defined as obstructive coronary artery disease (CAD, >50% stenosis), pulmonary embolism (PE), or aortic disease; secondary outcomes were radiation dose, contrast volume, and image quality.
From July 2007 to September 2013, 12,834 patients underwent CT scanning (1,555 TRO; 11,279 coronary CTA). The TRO group included more women (57.1% vs. 47.8%, p < 0.001). Diagnostic yield was similar (TRO 17.4% vs. coronary CTA 18.3%, p = 0.37), driven by CAD (15.5% vs. 17.2%, p = 0.093); PE and aortic disease were 1.1% and 0.4% (p = 0.004) and 1.7% and 1.1% (p = 0.046), respectively. TRO had higher median radiation (9.1 mSv vs. 6.2 mSv; p < 0.0001) and mean contrast (113 ± 6 ml vs. 89 ± 17 ml; p < 0.0001) doses. Nondiagnostic images were more frequent with TRO (9.4% vs. 6.5%; p < 0.0001). In emergency department patients, PE and aortic disease were more often detected on TRO. Among inpatients, there were no differences in overall yield, or in yield for PE, aortic disease, or CAD.
TRO was associated with slightly higher yield of PE and aortic disease, specifically in the emergency department. This benefit comes with higher nondiagnostic image quality, radiation, and contrast doses. Although TRO may be of value in selected patients, its indiscriminate use is not warranted. The authors concluded that the appropriate use of TRO needs to be further defined.
This statewide quality improvement registry suggests that a TRO scan was associated with a slightly higher yield than coronary CTA for detecting PE and aortic pathology in an emergency department setting; but at the cost of image quality, and higher doses of radiation and intravenous contrast. Selection bias could explain some of the diagnostic findings in this observational study, in that the suggested diagnostic protocol directed patients toward CTA if there was no clinical suspicion for PE or acute aortic pathology. With literally billions of health care dollars spent annually for the use of advanced imaging in this scenario, the compromise in image quality and radiation and contrast doses associated with a TRO scan compared to coronary CTA among patients with intermediate suspicion for PE or aortic disease probably would be best addressed in a prospective trial.
Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease, Interventions and Imaging, Interventions and Structural Heart Disease, Interventions and Vascular Medicine, Angiography, Computed Tomography, Nuclear Imaging
Keywords: Aortic Diseases, Chest Pain, Constriction, Pathologic, Coronary Angiography, Coronary Artery Disease, Diagnostic Imaging, Emergency Service, Hospital, Heart Valve Diseases, Pulmonary Embolism, Radiation Dosage, Tomography, X-Ray Computed
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