Abstract 680: Standard vs “Triple Rule-Out” Protocol Computed Tomographic Angiography for Evaluation of Acute Chest Pain: Comparative Diagnostic Yield and 3-Month Outcomes
Background: “Triple rule-out” (TRO) protocols have the ability to simultaneously evaluate coronary artery disease, pulmonary embolism (PE), and aortic dissection (AD). However, the diagnostic yield and clinical outcomes of TRO compared to standard coronary CT angiography (CCTA) have not been delineated.
Methods: This retrospective study included patients undergoing TRO or CCTA at our institution who had complete three month follow up data and were enrolled in an ongoing statewide quality assurance registry. All images were interpreted by cardiologists for coronary findings and thoracic radiologists for non-cardiac findings. TRO and CCTA groups were compared for baseline demographics, clinical presentation, coronary artery disease, PE, AD, contrast and radiation doses, and 3-month outcomes.
Results: From July 2, 2007 to July 6, 2008, 2,766 patients were enrolled in the registry (TRO, N = 427 and CCTA, N = 2339). Compared to those in the CCTA group, TRO patients were more often female (59 % v 44 %, p < 0.0001), with atypical symptoms (92 % v 80 %, p < 0.0001), younger in age (53±13 vs. 56±13 years, p = 0.0003), and with lower rates of coronary stenoses >50 % (17 % v 23 %, p = 0.015). In TRO and CCTA, combined PE and AD rates were low (1.9 % and 0.2 %, respectively), with PE more common in the TRO group (1.9 % v 0.1 %, p < 0.0001). No AD were identified in TRO and 1 was noted on CCTA (p = 1.00). Compared to CCTA, TRO had higher median radiation (15±7 mSv v 11±6 mSv, p < 0.0001) and contrast dose (119±12 mL v 86±15 mL, p < 0.0001). No significant differences were noted in 3-month outcomes between groups with respect to death (p = 0.19), acute coronary syndromes (p = 0.87), hospitalizations (p = 0.54), emergency room evaluations (p = 0.06), stress tests (p = 0.24), or cardiac catheterizations (0.83). Over 3-months of follow up, TRO patients underwent revascularization less frequently than CCTA patients (3.0 % v 5.8 %, p = 0.02).
Conclusions: For evaluating acute chest pain, the TRO protocol has a low diagnostic yield for PE and AD and is associated with significantly higher radiation and contrast doses compared to CCTA. These findings raise concerns regarding the benefit of TRO and highlight potentially harmful effects. TRO should be used parsimoniously, particularly in younger and female patients.