Coronary Artery Calcium Scoring in the Emergency Department: Identifying Which Patients With Chest Pain Can Be Safely Discharged Home
Presented at the annual meeting of the American Heart Association, November 2008, New Orleans, LA; and at the 9th Biennial International Conference of Non-Invasive Cardiovascular Imaging, May 2009, Barcelona, Spain.
Received 9 September 2009; received in revised form 30 November 2009, 16 December 2009 and 5 January 2010; accepted 13 January 2010. published online 08 February 2010. Corrected Proof
Study objective
Coronary artery calcium scoring (CACS) is a simple and readily available test for identifying coronary artery disease. Our objective is to evaluate whether a CACS of zero will identify chest pain patients who can be safely discharged home, without need for further cardiac testing.
Methods
This was a prospective observational cohort study conducted at an urban tertiary care hospital of stable patients presenting to the emergency department (ED) with chest pain of uncertain cardiac cause. Patients with a normal initial troponin level, nonischemic ECG, and no history of coronary artery disease had stress myocardial perfusion imaging (SPECT) and CACS within 24 hours of ED admission. Cardiac events were defined as an acute coronary syndrome during the index hospitalization or in follow-up. CACS results were assessed in relation to SPECT findings and cardiac events.
Results
The 1,031 patients enrolled (mean [SD] age 54 [13] years) had a median CACS of 0 (61% with CACS of 0). The frequency of an abnormal SPECT ranged from 0.8% (CACS of 0) to17% (CACS>400). Cardiac events occurred in 32 patients (3.1%) during the index hospitalization (N=28) or after hospital discharge (N=4) (mean 7.4 [3.3] months). Only 2 events occurred in 625 patients with a CACS of 0 (0.3%; 95% confidence interval 0.04% to 1.1%). Thus, 2 of 32 patients with a cardiac event had a CACS of 0 (6%; 95% confidence interval 0.8% to 21%). Both of these patients developed increased troponin levels during their index visit but had normal serial ECG and SPECT study results and no cardiac events at 6-month follow-up.
Conclusion
A majority of patients (61% in our sample) evaluated for chest pain of uncertain cardiac cause have a CACS of 0, which predicts both a normal SPECT result and an excellent short-term outcome. Our results suggest that patients with a CACS of 0 can be discharged home, without further cardiac testing.
Methodist DeBakey Heart and Vascular Center, The Methodist Hospital, Houston, TX
Address for correspondence: John J. Mahmarian, MD, Methodist DeBakey Heart and Vascular Center, 6550 Fannin St, Ste 677, Houston, TX 77030; 713-441-2849, fax 713-793-7034
Supervising editor: Keith A. Marill, MD
Author contributions: JJM conceived and initiated the study, proposed its design, and interpreted the data. CMP participated in the design of the study. FN, SMC, and MEF assisted with data acquisition. JP and LEP performed statistical analysis. SMC and JJM drafted the article. CMP and MEF provided critical review of the article. FN, SMC, JP, and LEP reviewed the article, and all authors approved the final draft. All the authors had full access to all of the data in this study and take full responsibility for the integrity of the data and the accuracy of the analysis. JJM takes responsibility for the paper as a whole.
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article that might create any potential conflict of interest. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement. Supported in part by a grant from the Methodist Hospital Foundation, Houston, TX, whose representatives assisted in the initial data collection for the trial.
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