Cardiology/original research
The Diagnostic Accuracy of 64-Slice Computed Tomography Coronary Angiography Compared With Stress Nuclear Imaging in Emergency Department Low-Risk Chest Pain Patients

Presented in part at the American Heart Association, Scientific Sessions, November 2005, Dallas, TX.
https://doi.org/10.1016/j.annemergmed.2006.06.043Get rights and content

Study objective

We compared the accuracy of multidetector computed tomography (CT) coronary angiography with stress nuclear imaging for the detection of an acute coronary syndrome or 30-day major adverse cardiac events in low-risk chest pain patients.

Methods

This was a prospective study of the diagnostic accuracy of myocardial perfusion imaging and multidetector CT in low-risk chest pain patients. The target condition was an acute coronary syndrome (confirmed >70% coronary stenosis on coronary artery catheterization) or major adverse cardiac events within 30 days. Patients were low risk by Reilly/Goldman criteria and had negative serial ECGs and cardiac markers. All had both rest/stress sestamibi nuclear imaging and multidetector CT. Patients with abnormal stress nuclear imaging results (reversible perfusion defects) or multidetector CT results (stenosis >50% or calcium score >400) were considered for cardiac catheterization, and those with discordant results had a greater than 30-day reevaluation (including ECG) by a cardiologist. All were followed up for evidence of major adverse cardiac events within 30 days by review of hospital records and structured telephone interview. Primary outcomes were the accuracy of multidetector CT and myocardial perfusion imaging for the detection of an acute coronary syndrome and 30-day major adverse cardiac events.

Results

Of the 92 patients, 7 (8%) were excluded because of uninterpretable multidetector CT scans. Of the remaining 85 study patients (49±11 years, 53% men), 7 (8%) were found to have the target condition, with all having significant coronary stenosis (88%±9%) and none having myocardial infarction or major adverse cardiac events during 30 days. Stress nuclear imaging results were negative in 72 (85%) patients, and multidetector CT results were negative in 73 (86%) patients. The sensitivity of stress nuclear imaging was 71% (95% confidence interval [CI] 36% to 92%), and multidetector CT was 86% (95% CI 49% to 97%), and the specificity was 90% (95% CI 81% to 95%) and 92% (95% CI 84% to 96%), respectively. The negative predictive value of stress nuclear imaging and multidetector CT was 97% (95% CI 90% to 99%) and 99% (95% CI 93% to 100%), respectively, and the positive predictive value was 38% (95% CI 18% to 64%) and 50% (95% CI 25% to 75%), respectively.

Conclusion

The accuracy of multidetector CT is at least as good as that of stress nuclear imaging for the detection and exclusion of an acute coronary syndrome in low-risk chest pain patients.

Introduction

Each year, roughly 6 million patients are evaluated for chest pain in emergency departments (EDs).1 Accurate and efficient screening for patients with an acute coronary syndrome is essential. Historically, 2% to 10% of patients with an acute coronary syndrome are inappropriately sent home from the ED.2 Missed diagnosis of acute myocardial infarction is associated with significant morbidity, and it is the leading contributor to malpractice claims paid by emergency physicians.3 Because of this, many patients are admitted for further testing, with the majority found to not have an acute coronary syndrome. It is estimated that the cost of these negative evaluations is $10 to $13 billion per year. To address these issues, EDs have developed chest pain units and diagnostic protocols. These protocols commonly include serial cardiac serum marker evaluations and ECGs, followed by stress testing, with or without radionuclide imaging.4, 5

Rapid advances in multidetector computed tomographic (CT) technology have allowed noninvasive coronary artery imaging. Studies comparing 64-slice multidetector CT with invasive coronary angiography have shown that multidetector CT performs well in the detection of significant coronary stenosis, with sensitivities ranging from 82% to 95% and specificities of 82% to 98%.6, 7, 8, 9 The presence of coronary calcification in patients with acute chest pain has also been shown to be predictive of future cardiac events.10 However, there are no studies that compare the ability of multidetector CT to detect an acute coronary syndrome with traditional stress nuclear imaging in low-risk chest pain patients.

Our study objective was to compare the diagnostic accuracy of multidetector CT with traditional stress nuclear imaging for the detection of an acute coronary syndrome in ED low-risk chest pain patients.

Section snippets

Materials and methods

This was a prospective institutional review board–approved study comparing the diagnostic accuracy of multidetector CT and radionuclide rest/stress imaging in a convenience sample of low-risk chest pain patients. Study patients received a multidetector CT and a radionuclide stress test, thus allowing each patient to serve as his or her own control.

Results

Patient enrollment occurred during 7 months, from September 2004 to March 2005. Throughout the study period, there were 68,367 ED visits, of which 2,182 patients (age 58±16 years; 46% men) were sent to the ED observation unit for the chest pain diagnostic protocol; 13% were subsequently admitted.

Limitations

This study has several important limitations to consider. Using the results of the multidetector CT and stress nuclear imaging to determine who would undergo angiography or who would have a follow-up appointment may have introduced an incorporation bias. Because we did not feel it ethical to withhold test results from those treating patients, knowledge of multidetector CT or stress nuclear imaging results may have also introduced a referral bias. Because cardiac catheterization did not occur in

Discussion

This study shows that multidetector CT has accuracy that is comparable to that of stress nuclear imaging for the detection of an acute coronary syndrome in ED low-risk chest pain patients. As such, it appears to be a reasonable alternative to stress nuclear imaging in a “low-risk” ED chest pain population after negative serial ECG and cardiac marker results.

During the last 2 decades, there has been a progressive evolution in the management of ED chest pain patients at risk for an acute coronary

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  • Cited by (0)

    Supervising editors: Judd E. Hollander, MD; Michael L. Callaham, MD

    Author contributions: MJG, MAR, GLR, JAG, and BO conceived and designed the study. MJG, GLR, JAG, and WWO obtained internal funding to support the study. All were engaged in patient enrollment. MJG, MAR, GLR, and BO were involved in data analysis and article preparation. All authors were involved in final article revisions. MR takes responsibility for the paper as a whole.

    Funding and support: Sponsored in part by a grant from the Minestrelli Advanced Cardiac Research Imaging Center, Royal Oak, MI.

    Reprints not available from the authors.

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