A time and imaging cost analysis of low-risk ED observation patients: a conservative 64-section computed tomography coronary angiography “triple rule-out” compared to nuclear stress test strategy

The Role of Triple Rule-out CT in an Indian Emergency Setting

Background

Emergency physicians are acutely aware of the consequences of missing fatal diagnoses for acute non-traumatic chest pain and subjecting patients to over-testing. In the large arsenal of tests that are available to us, a triple rule-out computed tomography (TRO-CT) Angiography is often less pursued, due to concerns about their efficacy and safety or because of nescience. We aim to find the yield of the test in an Indian emergency setting and impart some knowledge about it along the way.

Materials and methods

Twenty-six patients who presented to the emergency department of our institute with acute chest pain, with non-specific electrocardiogram (ECG) findings and negative serial troponin I, underwent TRO-CT. HEART scores of all patients, calculated at their presentation, were correlated with TRO-CT findings.

Results

Triple rule-out computed tomography angiography was positive in 5 patients (20%), of which 4 cases (16%) were diagnosed to have significant coronary artery disease and one had an acute pulmonary embolism. All 4 patients who had significant coronary artery disease (CAD) diagnosed by TRO-CT had a HEART score of intermediate risk. The mean effective radiation dose of the entire TRO study was 19.024 ± 3.319 mSv (range = 13.89-25.95 mSv).

Conclusion

Triple rule-out CT angiography is a useful tool in the evaluation of patients presenting with acute chest pain in the emergency and can be an important adjunct in ruling out significant CAD in intermediate-risk patients. Emergency physicians and young residents need to know about this tool in their armamentarium to tackle doubtful cases.

How to cite this article

Pattereth N, Chaliyadan S, Mathew R, Kumar S, Das CJ, Aggarwal P. et al. The Role of Triple Rule-out CT in an Indian Emergency Setting. Indian J Crit Care Med 2023;27(3):190-194.

In-Hospital Cost Comparison of Triple-Rule-Out Computed Tomography Angiography Versus Standard of Care in Patients With Acute Chest Pain

PURPOSE

The purpose of this study was to evaluate the utilization of invasive and noninvasive tests and compare cost in patients presenting with chest pain to the emergency department (ED) who underwent either triple-rule-out computed tomography angiography (TRO-CTA) or standard of care.

MATERIALS AND METHODS

We performed a retrospective single-center analysis of 2156 ED patients who presented with acute chest pain with a negative initial troponin and electrocardiogram for myocardial injury. Patient cohorts matched by patient characteristics who had undergone TRO-CTA as a primary imaging test (n=1139) or standard of care without initial CTA imaging (n=1017) were included in the study. ED visits, utilization of tests, and costs during the initial episode of hospital care were compared.

RESULTS

No significant differences in the diagnosis of coronary artery disease, pulmonary embolism, or aortic dissection were observed. Median ED waiting time (4.5 vs. 7.0 h, P<0.001), median total length of hospital stay (5.0 vs. 32.0 h, P<0.001), hospital admission rate (12.6% vs. 54.2%, P<0.001), and ED return rate to our hospital within 30 days (3.5% vs. 14.6%, P<0.001) were significantly lower in the TRO-CTA group. Moreover, reduced rates of additional testing and invasive coronary angiography (4.9% vs. 22.7%, P<0.001), and ultimately lower total cost per patient (11,783$ vs. 19,073$, P<0.001) were observed in the TRO-CTA group.

CONCLUSIONS

TRO-CTA as an initial imaging test in ED patients presenting with acute chest pain was associated with shorter ED and hospital length of stay, fewer return visits within 30 days, and ultimately lower ED and hospitalization costs.

Triple rule-out computed tomography for risk stratification of patients with acute chest pain

AIMS

Clinical evidence supporting triple rule-out computed tomography (TRO-CT) for rapid screening of cardiovascular disease is limited. We investigated the clinical value of TRO-CT in patients with acute chest pain.

METHODS

We retrospectively enrolled 1024 patients who visited the emergency department (ED) with acute chest pain and underwent TRO-CT using a 128-slice CT system. TRO-CT was classified as "positive" if it revealed clinically significant cardiovascular disease including obstructive coronary artery disease, pulmonary thromboembolism, or acute aortic syndrome. The clinical endpoint was occurrence of a major adverse cardiovascular event (MACE) within 30 days, defined by a composite of all cause death, myocardial infarction, revascularization, major cardiovascular surgery, or thrombolytic therapy. Clinical risk scores for acute chest pain including TIMI, GRACE, Diamond-Forrester, and HEART were determined and compared to the TRO-CT findings.

RESULTS

TRO-CT revealed clinically significant cardiovascular disease in 239 patients (23.3%). MACE occurred in 119 patients (49.8%) with positive TRO-CT and in 7 patients (0.9%) with negative TRO-CT (p < 0.001). Sensitivity, specificity, positive predictive value, and negative predictive value of TRO-CT was 95%, 88%, 54%, and 99%, respectively. TRO-CT was a better discriminator between patients with vs. without events as compared to clinical risk scores (c-statistics = 0.91 versus 0.64 to 0.71; integrated discrimination improvement = 0.31 to 0.37; p < 0.001 for all comparisons). Patients with a negative TRO-CT showed shorter ED stay times and admission rates compared to patients with positive TRO-CT, irrespective of clinical risk scores (p < 0.001 for all comparisons).

CONCLUSION

Triple rule-out CT has high predictive performance for 30-day MACE and permits rapid triage and low admission rates irrespective of clinical risk scores.

Diagnostic Yield of Triple-Rule-Out CT in an Emergency Setting

OBJECTIVE

The objective of the present study is to quantify the diagnostic yield of triple-rule-out (TRO) CT for the evaluation of acute chest pain in emergency department patients.

MATERIALS AND METHODS

All TRO CT studies performed at our institution from 2006 to 2015 were reviewed. Scans were performed on a 256-MDCT scanner, with the use of ECG gating and a biphasic contrast injection. Radiology reports were reviewed to identify diagnoses that could explain chest pain, including coronary and noncoronary diagnoses, and significant incidental findings that did not account for the patient's presentation. The total numbers of coronary and noncoronary diagnoses and incidental findings were calculated.

RESULTS

Four of 1196 total cases that were identified were excluded from the study because of inadequate image quality. A total of 970 patients (81.4%) had a negative study result without a significant coronary or noncoronary diagnosis. A total of 139 patients (11.7%) had significant coronary artery disease (50% stenosis or greater). One hundred six patients (8.9%) had a noncoronary diagnosis that could explain chest pain (p < 0.02), most commonly pulmonary embolism (28 patients [2.3%]), aortic aneurysm (24 patients [2.0%]), or pneumonia (20 patients [1.7%]). Thirty cases (27.3%) of pulmonary embolism and aortic pathologic findings would not have been detected with coronary CT angiography because of unopacified right-side circulation or limited z-axis coverage. A total of 528 incidental findings not considered to explain chest pain were noted in 418 patients (35.1%).

CONCLUSION

In 8.9% of patients, TRO CT detected a significant noncoronary diagnosis that could explain acute chest pain, including pathologic findings that would not be identified on dedicated coronary CT angiography.

Triple rule-out computed tomographic angiography for chest pain: a diagnostic systematic review and meta-analysis

OBJECTIVES

The objective was to compare the image quality, diagnostic accuracy, radiation exposure, and contrast volume of "triple rule-out" (TRO) computed tomography (CT) to other diagnostic modalities commonly used to evaluate patients with nontraumatic chest pain (dedicated coronary, pulmonary embolism [PE], and aortic dissection CT; invasive coronary angiography; and nuclear stress testing).

METHODS

Four electronic databases were searched, along with reference lists and contacted content experts, for relevant studies from inception until October 2012. Eligible studies enrolled patients with nontraumatic chest pain, shortness of breath, suspected acute coronary syndrome (ACS), PE, or aortic dissection; used at least 64-slice CT technology; and compared TRO CT to another diagnostic modality.

RESULTS

Eleven studies enrolling 3,539 patients (791 TRO and 2,748 non-TRO) were included (one randomized controlled trial and 10 observational). There was no significant difference in image quality between TRO and dedicated CT scans. TRO CT had the following pooled diagnostic accuracy estimates for coronary artery disease: sensitivity of 94.3% (95% confidence interval [CI] = 89.1% to 97.5%), specificity of 97.4% (95% CI = 96.1% to 98.4%), positive likelihood ratio (LR+) of 17.71 (95% CI = 3.92 to 79.96), and negative likelihood ratio (LR-) of 0.08 (95% CI = 0.02 to 0.27). There were insufficient numbers of patients with PE or aortic dissection to generate diagnostic accuracy estimates for these conditions. Use of TRO CT involved greater radiation exposure (mean difference [MD] = 4.84 mSv, 95% CI = 1.65 to 8.04 mSv) and contrast exposure (MD = 38.0 mL, 95% CI = 28.1 to 48.0 mL) compared to non-TRO CT patients.

CONCLUSIONS

Triple rule-out CT is highly accurate for detecting coronary artery disease. Given the low (<1%) prevalence of PE and aortic dissection in the included studies, and the increased radiation and contrast exposure, there are insufficient data to recommend use of TRO CT in the diagnosis of these conditions.

Risk stratification in chest pain patients undergoing nuclear stress testing: the Erlanger Stress Score

BACKGROUND

Studies have individually reported the relationship of age, cardiac risk factors, and history of preexisting coronary artery disease (CAD) for predicting acute coronary syndromes in chest pain patients undergoing cardiac stress testing. In this study, we investigate the interplay of all these factors on the incidence of acute coronary syndromes to develop a tool that may assist physicians in the selection of appropriate chest pain patients for stress testing.

METHODS

Retrospective analysis of a prospectively acquired database of consecutive chest pain patients undergoing nuclear stress testing. Backward stepwise logistic regression was used to develop a model for predicting risk of 30-day acute coronary events (ACE) using information obtained from age, sex, cardiac risk factors, and history of preexisting CAD.

RESULTS

A total of 800 chest pain patients underwent nuclear stress testing. ACE occurred in 74 patients (9.3%). Logistic regression analysis found only 6 factors predictive of ACE: age, male sex, preexisting CAD, diabetes, and hyperlipidemia. Area under the receiver operator characteristic curve of this model for predicting ACE was 0.767 (95% confidence interval, 0.719-0.815). There were no cases of ACE in the 173 patients with predicted probability estimates ≤2.5% (95% confidence interval, 0%-2.1%).

CONCLUSIONS

A regression model using age, sex, preexisting CAD, diabetes, and hyperlipidemia is predictive of 30-day ACE in chest pain patients undergoing nuclear stress testing. Prospective studies need to be performed to determine whether this model can assist physicians in the selection of appropriate low-to-intermediate risk chest pain patients for nuclear stress testing.

CTA in the evaluation of acute chest pain syndromes. Should more widespread use be advocated?

INTRODUCTION

With the advent of CT more than 3 decades ago, we have seen rapid evolution of this technology, so that we are now able to noninvasively accurately image the coronary arterial tree. This has opened up a debate as to the role of this imaging modality in our day-to-day evaluation of acute coronary syndromes. Much recent literature has focused on whether in the acute setting this modality should be incorporated into current evaluation and treatment guidelines.

AREAS COVERED

A comprehensive review of a literature illustrating the utility of CTA in the acute care setting is presented. The paper goes on to address the benefits and challenges of implementation of CTA in the evaluation of acute chest pain syndromes. Alternative guidelines and insights on future directions are presented.

EXPERT OPINION

In this current era where CAD, and more specifically acute chest pain syndromes, remains as a large part of ED visits and also healthcare costs, CTA will play an important role in the diagnosis and treatment of individuals. It remains only a matter of time when this will be implemented in our guidelines, in light of the recent literature and ever improving CTA protocols.

Economic outcome of cardiac CT-based evaluation and standard of care for suspected acute coronary syndrome in the emergency department: a decision analytic model

RATIONALE AND OBJECTIVES

Cardiac computed tomography (CCT) in the emergency department may be cost saving for suspected acute coronary syndrome (ACS), but economic outcome data are limited. The objective of this study was to compare the cost of CCT-based evaluation versus standard of care (SOC) using the results of a clinical trial.

MATERIALS AND METHODS

We developed a decision analytic cost-minimization model to compare CCT-based and SOC evaluation costs to obtain a correct diagnosis. Model inputs, including Medicare-adjusted patient costs, were primarily obtained from a cohort study of 102 patients at low to intermediate risk for ACS who underwent an emergency department SOC clinical evaluation and a 64-channel CCT. SOC costs included stress testing in 77% of patients. Data from published literature completed the model inputs and expanded data ranges for sensitivity analyses.

RESULTS

Modeled mean patient costs for CCT-based evaluation were $750 (24%) lower than the SOC ($2384 and $3134, respectively). Sensitivity analyses indicated that CCT was less expensive over a wide range of estimates and was only more expensive with a CCT specificity below 67% or if more than 44% of very low risk patients had CCT. Probabilistic sensitivity analysis suggested that CCT-based evaluation had a 98.9% probability of being less expensive compared to SOC.

CONCLUSION

Using a decision analytic model, CCT-based evaluation resulted in overall lower cost than the SOC for possible ACS patients over a wide range of cost and outcome assumptions, including computed tomography-related complications and downstream costs.

Can the HEART score safely reduce stress testing and cardiac imaging in patients at low risk for major adverse cardiac events?

BACKGROUND

Patients with low-risk chest pain have high utilization of stress testing and cardiac imaging, but low rates of acute coronary syndrome (ACS). The objective of this study was to determine whether the HEART score could safely reduce objective cardiac testing in patients with low-risk chest pain.

METHODS

A cohort of chest pain patients was identified from an emergency department-based observation unit registry. HEART scores were determined using registry data elements and blinded chart review. HEART scores were dichotomized into low (0-3) or high risk (>3). The outcome was major adverse cardiac events (MACE); a composite end point of all-cause mortality, myocardial infarction, or coronary revascularization during the index visit or within 30 days. Sensitivity, specificity, and potential reduction of cardiac testing were calculated.

RESULTS

In a span of 28 months, the registry included 1070 low-risk chest pain patients. MACE occurred in 0.6% (5/904) of patients with low-risk HEART scores compared with 4.2% (7/166) with a high-risk HEART scores (odds ratio = 7.92; 95% confidence interval [95% CI]: 2.48-25.25). A HEART score of >3 was 58% sensitive (95% CI: 32-81%) and 85% specific (95% CI: 83-87%) for MACE. The HEART score missed 5 cases of ACS among 1070 patients (0.5%) and could have reduced cardiac testing by 84.5% (904/1070). Combination of serial troponin >0.065 ng/mL or HEART score >3 resulted in sensitivity of 100% (95% CI: 72-100%), specificity of 83% (95% CI: 81-85%), and potential reduction in cardiac testing of 82% (879/1070).

CONCLUSIONS

If used to guide stress testing and cardiac imaging, the HEART score could substantially reduce cardiac testing in a population with low pretest probability of ACS.

Cardiac CT in the emergency department: convincing evidence, but cautious implementation

In clinical practice, assessment of chest pain patients presenting to the emergency department is difficult and the work-up can be lengthy and costly. There is growing evidence supporting the use of coronary computed tomography angiography (CTA) in early assessment of patients presenting with acute chest pain to the emergency department. CTA appears to be a faster and more accurate way to diagnosis or rule out coronary stenosis, leading to reduced hospital admissions, decreased time in the ED and lower costs. The focus of this article is to review the current literature of the use of Coronary CTA and "triple rule out" protocols in the emergency department setting and to provide a chest pain algorithm, showing how Coronary CTA can be implemented effectively in clinical practice. Potential pitfalls and requirements for implementation will also be discussed.