Curr Cardiovasc Imaging Rep (2015) 8: 21 DOI 10.1007/s12410-015-9337-x

CARDIAC COMPUTED TOMOGRAPHY (TC VILLINES, SECTION EDITOR)

Strategy for Building a Successful Coronary CT Angiography Program in the Emergency Department Christopher D. Maroules 1 & Ricardo C. Cury 2 & Brian B. Ghoshhajra 3 & Udo Hoffmann 3 & Harold I. Litt 4 & Ron Blankstein 5 & Suhny Abbara 1

Published online: 24 April 2015 # Springer Science+Business Media New York 2015

Abstract Coronary CT angiography (cCTA) is a rapid, accurate, safe, and efficient technique for evaluating acute chest pain in patients with low-intermediate pretest probability of coronary artery disease. In this review, we outline a strategy for building and maintaining a successful cCTA program in the emergency department. We define success as the ability for a program to improve patient outcomes and yield cost savings for a health care organization. Establishing a successful program can be achieved by organizing a multidisciplinary task force, developing a shared vision, utilizing established guidelines, developing standardized workflow and chest pain management pathways, launching an effective educational campaign, and implementing a quality assurance program.

Keywords Coronary CT angiography . Acute chest pain . Emergency department . Cardiac computed tomography

Introduction Chest pain is one of the most common presentations in the emergency department (ED), with over nine million visits each year at an estimated cost of over six billion dollars annually [1]. Despite the large volume of acute chest pain in the ED, only a small percentage of patients have acute coronary syndrome (ACS). Thus, ED physicians are challenged with the task of accurately and efficiently identifying the proportionately small number of patients with ACS in the setting of a

This article is part of the Topical Collection on Cardiac Computed Tomography * Christopher D. Maroules [email protected] Ricardo C. Cury [email protected] Brian B. Ghoshhajra [email protected]

1

Department of Radiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8896, USA

2

Department of Radiology, Baptist Hospital of Miami and Baptist Cardiac and Vascular Institute, Miami, FL, USA

3

Cardiac MR PET CT Program, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA

4

Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA

5

Noninvasive Cardiovascular Imaging Program, Departments of Medicine and Radiology, Brigham and Women’s Hospital, Boston, MA, USA

Udo Hoffmann [email protected] Harold I. Litt [email protected] Ron Blankstein [email protected] Suhny Abbara [email protected]

21 Page 2 of 10

large chest pain volume and expanding logistic burdens, including management of increasingly overcrowded EDs. These logistic burdens have shown to negatively impact the quality of care and patient outcomes [1, 2]. Current standard of care for evaluating patients with low or intermediate pretest probability of coronary artery disease (CAD) is expensive and time consuming, involving initial assessment (history, physical exam, electrocardiogram (ECG), and cardiac biomarkers) followed by an observation period of several hours and subsequent stress testing. Thus, a more efficient strategy to safely evaluate and triage acute chest pain has the potential to deliver both health and economic benefits. Coronary CT angiography (cCTA) is a robust and reliable technique for evaluating coronary atherosclerosis with excellent sensitivity for detecting coronary stenosis compared to the gold standard invasive coronary angiography (Fig. 1) [3]. Further, data from several recent randomized controlled trials supports a cCTA-based approach for the triage of acute chest pain in select patients [4–6]. In this review, we outline a strategy for building and maintaining a successful cCTA program in the ED. Developing a

Fig. 1 cCTA cases from the ED. Top panel, a 56-year-old male with acute chest pain (TIMI score 2) was found to have severe (>70 %) stenosis in the proximal RCA (arrow) and mild stenosis (<50 %) in the mid-RCA (arrowhead). The patient underwent invasive coronary angiography which confirmed focal 95 % stenosis in the proximal RCA and focal 40 % stenosis in the mid-RCA. A drugeluting stent was placed in the proximal RCA. Bottom panel, 47year-old female with acute chest pain (TIMI score 2) was found to have normal RCA (c), LAD (d), and LCX (e), and was subsequently discharged from the ED. ED emergency department, LAD left anterior descending coronary artery, LCX left circumflex coronary artery, RCA right coronary artery, TIMI thrombolysis in myocardial infarction

Curr Cardiovasc Imaging Rep (2015) 8: 21

successful program takes time, multidisciplinary collaboration, and careful planning, but has the potential to improve patient outcomes and resource utilization as well as yield cost savings for health care payors.

The Evidence Four recent randomized controlled trials have established cCTA as a rapid, accurate, safe, and efficient technique for evaluating acute chest pain in patients with low-intermediate pretest probability of CAD (Table 1). These trials have demonstrated that a cCTA-based approach for acute chest pain triage can lead to more rapid and direct discharge from the ED, particularly when the exam is normal. In the CT-STAT [5], Goldstein et al. evaluated 699 subjects randomized to cCTA or usual care, which included myocardial perfusion single photon emission computed tomography (SPECT). Investigators observed a 54 % reduction in time to diagnosis within the cCTA group (median 2.9 vs 6.3 h, p<0.0001), with similar radiation exposure to usual care. In the ACRIN-PA

Curr Cardiovasc Imaging Rep (2015) 8: 21 Table 1

Page 3 of 10 21

Randomized controlled trials of cCTA in the ED

Outcome

CT-STAT [5] (n=699)

ACRIN-PA [4] (n=1370)

ROMICAT II [6] (n=1000)

Safety (% MACE during follow-up with normal or negative cCTA) Total hospital length of stay, all subects (h) Time to diagnosis (h) Radiation exposure (cCTA vs SPECT) (mSv) ED costs (dollars)

0.8 % at 6-month follow-up (no difference compared to usual care, p=0.29) NA

0 % MACE at 30 days

0.4 % MACE at 28 days (no difference compared to usual care, p=0.18)

18.0 (cCTA) vs 24.8 (usual care), p<0.001 NA NA

23.2 (cCTA) vs 30.8 (usual care), p<0.001

NA

$2101 (cCTA) vs $2566 (usual care), p<.001

NA

$4289 (cCTA) vs $4060 (usual care), p=0.65

Total hospital costs (dollars)

2.9 (cCTA) vs 6.2 (usual care), p<0.0001 11.5 (cCTA) vs 12.8 (SPECT), p=0.02 $2137 (cCTA) vs $3458 (usual care), p<.0001 NA

10.4 (cCTA) vs 18.7 (usual care), p<0.001 11.3 (cCTA) vs 14.1 (SPECT), p<0.001

Includes costs from index visit and follow-up visits cCTA coronary computed tomographic angiography, MACE major adverse cardiovascular events, SPECT single photon emission computed tomography

trial [4], Litt et al. randomized 1370 subjects to cCTA or usual care (2:1) and evaluated safety as a primary endpoint, defined as the absence of myocardial infarction (MI) or cardiac death during 30 days among subjects randomized to cCTA with no significant CAD on the index exam. Among the 640 subjects with negative cCTA, there were no MIs or cardiac deaths at 30 days. Results from ACRIN-PA also demonstrated higher ED discharge rate (49.6 vs 22.7 %) and shorter median length of stay (18.0 vs 24.8 h, p<0.001) in the cCTA group. In ROMICAT II [6], designed as a randomized controlled effectiveness trial to test the impact of cCTA on clinical decisionmaking as the primary endpoint, 1000 subjects were randomized to cCTA or usual care. Hoffmann et al. found no significant differences in major adverse cardiovascular events (MACE) between the cCTA and usual care groups. Further, ROMICAT II investigators demonstrated lower hospital length of stay (reduced by 7.6 h) and lower ED costs ($2101 vs $2566, p<0.001) in the cCTA group. However, more downstream testing and higher radiation exposure were noted in the cCTA group. Interestingly, in an analysis of sex-based differences from ROMICAT II, Truong et al. [7] observed a greater reduction in length of stay, lower hospital admission rate, and lower increased cumulative radiation dose in women compared to men (p for interaction <0.02), supporting a cCTA strategy for women presenting to the ED with chest pain. In a comprehensive meta-analysis by Hulten et al. [8••], length of stay and time to discharge were significantly shorter with cCTA compared to usual care in all four randomized controlled trials. While none of the randomized controlled trials were sufficiently powered to compare health outcomes, all trials demonstrated very low MACE after ED discharge in both cCTA and usual care groups. While the trials also demonstrated significant ED cost savings in patients undergoing cCTA compared to usual care, the use of cCTA was associated with increased downstream invasive coronary angiography and coronary revascularization [8••]. However, it remains unclear whether the observed increase in downstream testing

after cCTA represents an overuse of testing after cCTA or an underuse of testing in patients undergoing usual care. As such, larger studies with longer term follow-up will be necessary to critically evaluate these differences in downstream testing. In addition, while cCTA for acute chest pain triage is associated with greater radiation exposure than exercise treadmill testing and stress echocardiography approaches, radiation exposure with cCTA is lower than a SPECT-myocardial perfusion imaging (MPI) approach. Evidence from other observational [9, 10, 11•, 12] and single-center randomized trials [13•] evaluating associations between cCTA and clinical outcomes have yielded additional evidence supporting the safety of cCTA in the ED. For example, in a 2-year follow-up study [11•] of 333 subjects from the ROMICAT I trial, no subjects with a normal index exam experienced MACE, supporting a warranty period of at least 2 years with normal cCTA. Further, only 4.6 % of subjects with nonobstructive CAD (defined as <50 % stenosis) experienced MACE during the 2-year follow-up. In a single-center randomized prospective study of low-intermediate risk chest pain subjects suspected of ACS (CT-COMPARE), [13•] 562 subjects were randomized to either cCTA or exercise treadmill testing, and cCTA was associated with improved diagnostic performance as well as a 35 % reduction in length of stay and 20 % reduction in hospital costs.

Strategy for Building a Successful Program Building a successful cCTA program in the ED is contingent on (1) forming a cohesive multidisciplinary task force, (2) organizing a shared vision, (3) carefully reviewing established guidelines, (4) developing standardized workflow and chest pain management pathways, (5) launching an effective educational campaign, and (6) implementing a quality assurance program (Fig. 2). Effective communication and coordination of care between departments and providers is crucial for

21 Page 4 of 10

Curr Cardiovasc Imaging Rep (2015) 8: 21

Create a Vision and Define Local Opportunities

Fig. 2 Strategy for planning, development, and implementation of cCTA in the ED

establishing and sustaining a quality program, and to ensure delivery of the highest possible level of patient care [14]. Nonemergent cCTA should be performed at the home institution for at least 12 months prior to implementing an ED program, and at least 6 months should be allocated for program planning and development before the go-live date.

Assemble a Multidisciplinary Task Force The first step toward establishing a successful cCTA program in the ED is assembling a strong multidisciplinary task force. The task force should include representation from cardiology, radiology, emergency medicine, primary care, hospital administration, and information technology/informatics, if available. Key support personnel should also be represented in the task force, including a lead cardiac CT technologist, lead nursing staff, and an administrative assistant. An effective task force will combine strengths and resources from multiple departments into a cohesive group, offering a synergistic approach for developing and implementing a cCTA program. A wellrespected physician champion should be appointed to lead the task force and serve as Program Director. This individual should meet American Heart Association (AHA)/American College of Cardiology (ACC) level 3 training guidelines [15], or have attained the equivalent level of training, and should be viewed as a leader and role model by local medical staff [16••]. It is important the Program Director make him or herself available as a resource to other physicians, particularly throughout the initial months after program implementation as the ED transitions to a new chest pain workflow.

Once the task force has been organized, a clear vision for the program should be established and local opportunities defined. The Program Director can promote team productivity and establish a sense of urgency by setting deadlines and creating a series of short-term wins. All members of the task force should be encouraged to participate in establishing program goals and objectives, and individual members should be assigned specific positions and tasks. Key individuals should be utilized who can contribute experience and leadership to program development. We recommend writing a brief vision statement that describes the program’s major objectives so that future task force members can clearly understand the program’s goals. An overall flowchart should be developed that incorporates the new cCTA workflow in the ED, and this should be evaluated in the context of existing local policies and procedures to ensure smooth implementation. In addition, ED patient demographics and chest pain volume should be critically assessed to anticipate cCTA volume and resource demands. Understanding ED patient demographics is also important for evaluating the potential cost savings of cCTAguided triage. In an analysis of ROMICAT I participants, Hulten et al. compared total hospital costs of 368 subjects who received usual care to the projected costs of ED management based on cCTA [17]. Investigators found that a cCTAguided triage could reduce total hospital costs by up to 23 % if the prevalence of obstructive CAD in the local population was less than ~30 %. However, increased costs were anticipated in populations with higher prevalence of disease or those that have a high proportion of uninterpretable scans, as such patients were more likely to have costly downstream testing. These findings underscore the fact that implementation of a cCTA program, and ultimately the cost effectiveness of any such program, requires careful attention to selecting an appropriate patient population [18]. Review Established Guidelines Next, established SCCT guidelines for cCTA performance [19], interpretation and reporting [20], dose reduction [21], and evaluation of acute chest pain [16••] should be extensively reviewed by the task force to ensure all requirements are satisfied by the program. Technical guidelines will ensure image acquisition with the best possible image quality and lowest radiation dose. At least 64-slice multidetector CT systems should be used with temporal resolution less than 200 ms and detector collimation 0.5–0.625 mm. The goal for heart rate control is between 60 and 65 bpm depending on scanner technology [19]. Beta blockers should be administered by trained clinicians or nursing staff to achieve heart rate control in patients without contraindications [22]. Modern systems such as high-pitch helical and 256–320-slice multidetector

Curr Cardiovasc Imaging Rep (2015) 8: 21

scanners allow for very rapid acquisition and wide z-axis coverage, respectively, and are thus capable of generating excellent image quality at higher heart rates. Barring no contradindications, sublingual nitrates should be administered to all patients to improve coronary vasodilation. Images must be reviewed on 3D workstations, including axial images and multiplanar reconstructions of the minimum available slice thickness. Minimum intensity projections (MIP) and curved planar reformations (CPR) should be used adjunctively to evaluate the coronary tree. Consider protocol modifications for select populations, including patients with obesity, chronic obstructive pulmonary disease, and diabetes [14]. We recommend engaging vendors and local physicists early to optimize scanner output parameters and assist with dose reduction strategies. Additional quality standards have been developed by SCCT for performing cCTA in the ED [16••]. Program operation and hours of service should strike a balance between satisfying the needs of the ED and not overwhelming staff or cCTA resources. An advanced cardiac life support (ACLS)-certified physician should be available to respond to emergent complications and should be available for consultation on patient preparation and exam protocolling. All physicians interpreting cCTA must maintain level 2 certification or the equivalent, although board certification by the Certification Board of Cardiovascular Computed Tomography or Advanced Proficiency in Cardiac CT by the American College of Radiology is highly recommended [16••]. The Program Director should have a minimum 2 years clinical experience or at least 300 prior cCTA interpretations. The lead technologist should have experience with at least 100 cCTA scans and should be ACLS-certified or work within close proximity to an ACLS-certified nurse. Reporting for cCTA in the ED must also follow established guidelines [20]. With the expanding emphasis on population health, cCTA programs will be most effective if terminology is standardized for reporting key findings. We recommend developing a structured reporting template for consistent communication with referring physicians and mitigating confusion with the results interpretation. On the basis of maximum coronary stenosis on cCTA, we recommend stratifying patients into one of six groups: normal (no stenosis), minimal/mild (1– 49 % stenosis), moderate (50–69 % stenosis), severe (≥70 % stenosis), or inconclusive/nondiagnostic [23]. Plaque location, extent, and description (calcified, noncalcified, or mixed calcified/noncalcified) should also be described [16••]. The presence of potentially Bvulnerable^ (high risk) plaque features, including positive remodeling, spotty calcification (<3 mm punctate calcifications as part of partially calcified plaque), and low attenuation (<30 HU) plaque, should be mentioned, as these findings are more commonly associated with ACS. Final reports should be available to clinicians within 60 min of scan completion [16••].

Page 5 of 10 21

Develop Standardized Workflow and Management Standardizing workflow and chest pain management for cCTA in the ED is essential for the program to function smoothly. Appropriate use criteria must be rigidly followed to ensure cCTA is only performed in patients who stand to benefit from the exam. Multisociety guidelines [24] designate cCTA as appropriate for evaluating acute chest pain in patients with low or intermediate pretest probability of CAD and normal or equivocal baseline ECG and/or cardiac biomarkers. Standardized screening forms can help guide ED clinicians with appropriate patient selection. It is important to avoid Bindication creep,^ or the progressive trend toward selecting patients at very low risk (unlikely to benefit from cCTA), or at high risk (in whom functional testing or invasive angiography would be more appropriate). All patients should be screened for contraindications to cCTA. Absolute contraindications include advanced renal insufficiency and severe allergy to iodinated contrast (Table 2) [14]. As mounting evidence demonstrates the ability of cCTA to safely guide clinical decision-making in the ED, management pathways should be developed based on actionable information from the cCTA report. Management decisions should be evidence-based, and as prior cCTA trials have used 50 % stenosis as a threshold for further evaluation, a 50 % threshold should drive recommendations for additional functional or invasive testing prior to discharge [25]. In a prospective cohort study of 529 low-intermediate risk patients within a large, urban health care system presenting with acute chest pain, Cury et al. implemented a cCTA-based management protocol and demonstrated a 50 % reduction in length of stay [9]. Investigators noted that patients with negative or mild nonobstructed disease on cCTA (<50 % stenosis) could be safely discharged without further testing. To facilitate expeditious workflow, we recommend incorporating disposition recommendations into the cCTA report based on results from the study, taking into consideration patient comorbidities and other potential etiologies for chest pain that may warrant evaluation (Fig. 3). Patients with normal (0 % stenosis) or minimal/ mild disease (1–49 % stenosis) can be discharged, with the caveat that mild disease should prompt outpatient follow-up with a primary care physician or cardiologist to ensure adequate medical management and secondary prevention of CAD. Alternatively, patients with moderate disease (50– 69 % stenosis) or an inconclusive exam may require functional testing or invasive angiography. Detection of severe disease (≥70 % stenosis) should prompt consideration of invasive angiography versus functional testing. Assessment of resting myocardial perfusion with cardiac CT may provide incremental value over coronary stenosis by cCTA for detecting ACS in low-intermediate risk patients with acute chest pain. In a retrospective study of 35 subjects who underwent both cCTA and invasive angiography [26],

21 Page 6 of 10 Table 2

Curr Cardiovasc Imaging Rep (2015) 8: 21

Appropriate patient selection for cCTA in the ED

Indications [24] Pretest probability of CAD • Low or intermediate • Low or intermediate • Low or intermediate Absolute contraindications • Severe allergy to iodinated contrast (anaphylaxis) • Inability to lay flat • Inability to perform breath-hold Relative contraindications • Pregnancy or breastfeeding • Renal insufficiency • Contraindication to beta-blockers (severe asthma, COPD) • Contraindication to nitrates (severe aortic stenosis, erectile dysfunction medications • Cardiac arrhythmia, including refractory tachycardia • Known coronary artery calcium score >1000 • Negative coronary angiogram (either invasive or cCTA) within prior 2 years

ECG and cardiac biomarkers • Normal • Uninterpretable ECG • Nondiagnostic ECG or equivocal cardiac biomarkers

cCTA coronary CT angiography, CAD coronary artery disease, COPD chronic obstructive pulmonary disease, ECG electrocardiogram

identification of rest myocardial perfusion defects on cardiac CT significantly improved diagnostic accuracy for ACS compared to assessment of coronary stenosis alone (area under the curve 0.88 vs 0.79, p=0.02). Additional data [27, 28] suggest CT perfusion may improve the specificity and positive predictive value for ACS in select populations. However, as limited

Fig. 3 Representative management pathways based on actionable information from the cCTA report. After co-existing medical conditions and other etiologies for chest pain have been evaluated and appropriately managed/excluded (asterisk)

studies have evaluated the incremental value of CT perfusion in the ED setting, consensus for its integration in acute chest pain workflow has not yet been reached. Local information technology (IT) and informatics divisions should be leveraged to help establish best practices. Opportunities include integrating the electronic medical

Curr Cardiovasc Imaging Rep (2015) 8: 21 Table 3

Page 7 of 10 21

Safety considerations for cCTA in the emergency ED

Potential safety hazard

Opportunities to mitigate risk

1. Radiation exposure

2. Allergic reaction to iodinated contrast

3. Contrast-induced nephropathy

4. Unnecessary follow-up testing

• Follow principles of ALARA (Bas low as reasonably achievable^) to guide CT scanner output settings • Use prospective ECG triggering for patients with stable heart rates below 65*beats per minute • Use ECG-based tube-current modulation when conditions warrant retrospective ECG gating • Consult with scanner vendors and local medical physicists to consider additional dose reduction strategies, including iterative reconstruction and low kVp scanning • Consider alternate exams in patients with increased radiation sensitivity, including patients under age 35 • Consider urine/blood test to exclude pregnancy in premenopausal females before cCTA • Review medical chart and screen for allergies during ED triage • Avoid cCTA in patients with history of severe contrast allergy (i.e., bronchospasm, anaphylaxis) • Consider pretreatment with corticosteroids and/or antihistamines for patients with mild contrast allergy (i.e., hives) in accordance with institutional policy • Review medical chart for history of renal dysfunction during ED triage • Check renal function (ie serum creatinine) before cCTA; consider alternate exam if estimated glomerular filtration rate is less than 45 ml/min/m2 • Ensure adequate hydration before and after cCTA • Diabetics: discontinue metformin for 48 h after cCTA to prevent lactic acidosis • Adhere to appropriate use criteria [24] for patient selection. Limit cCTA in the ED for patients with low or intermediate pretest probability for coronary artery disease • Review medical chart for history of coronary artery disease; do not perform cCTA in patients with a normal coronary angiogram (invasive or cCTA) within the previous 2 years • Consider alternate exam in patients with known coronary artery disease

ALARA as low as reasonably achievable, cCTA coronary CT angiography, ECG electrocardiogram

record with PACS to allow for efficient access to patient health information which will aide both ED staff and interpreting physicians in guiding management decisions. Electronic communication systems between the ED and primary care can also facilitate patient management. For example, automated email alerts notifying primary care physicians when their patients undergo cCTA in the ED would offer an opportunity for clinicians to review results quickly and acknowledge follow-up instructions. In addition, point-of-care decision support tools could be customized to facilitate appropriate patient selection in the ED [29].

Table 4

Launch an Educational Campaign Successful programs recognize the value of local marketing and staff education prior to implementation. The ED, cardiology, and primary care services must all be informed of the new cCTA program. Hours of operation should be clearly communicated, with an effort to maximize coverage without overwhelming local resources. We recommend initially restricting cCTA hours of operation to the daytime workweek (i.e., 8:00 am–5:00 pm, Monday through Friday) to establish workflow efficiency before expanding coverage into nights

Barriers to a successful cCTA program in the ED

Level National and regional

Institutional (operational)

Institutional (technical)

Potential barriers • Government (CMS) resistance to providing cCTA reimbursements • Resistance of 3rd party payors to provide cCTA reimbursements • Need to continue demonstrating strong clinical efficacy and cost-effectiveness of cCTA • Large hospital networks and health care systems unwilling to change processes for acute chest pain management • Lack of support from clinical colleagues or disagreement on the effectiveness of cCTA • Lack of hospital administration support • Poor organization and/or limited planning prior to program implementation • Lack of multidisciplinary collaboration or unbalanced cardiology/radiology representation • No quality assurance program to review the program’s effectiveness, monitor progress, and address future challenges • CT equipment without sufficient cardiac imaging capabilities (ie minimum 64-slice multidetector CT) • Scanner parameters not optimized to limit radiation exposure and preserve diagnostic image quality • No cardiac CT readers with Level 2/3-certification • CT technologists not fully trained in cardiac imaging applications

cCTA coronary CT angiography, CMS Center for Medicare and Medicaid Services

21 Page 8 of 10

and weekends. Invariably most programs will experience workflow challenges during the first several months after going live which are easier to troubleshoot during daytime work hours. All receivers of cCTA reports in the ED, particularly midlevel providers, may not fully understand the implications of stenosis grading and should be brought up-to-speed. We recommend hosting a series of educational/informational workshops before the go-live date, including focused meetings with ED providers, nursing staff, CT technologists, and primary care providers. Since clinical obligations may preclude some staff from attending workshops, we recommend developing an informational slide show or online video that can be distributed to all staff. ED clinicians should be educated on key strengths and limitations of cCTA, including its strong negative predictive value but limited capability for evaluating functional ischemia [30]. In addition, ED clinicians should be reminded that a decision to admit or discharge is ultimately under their control, despite management recommendations outlined in the cCTA report. Implement a Quality Assurance Program A quality assurance program should be implemented for the cCTA program to periodically evaluate the program for deficiencies and identify areas for improvement. We recommend holding monthly task force quality assurance/process improvement meetings during the initial 6 months after implementation, and quarterly thereafter, to monitor the program’s progress. Monitoring should include an assessment of cCTA accuracy, appropriateness of exam ordering, and evaluation of dose indices. When available, cCTA interpretations should be reviewed with invasive angiography correlation and target accuracy should be greater than 75 % [16••]. The program should undergo regular peer review for quality improvement and to maintain site accreditation by the American College of Radiology (ACR). Appropriate action should be taken when significant discrepant findings are identified. If greater than 5 % of cCTA exams are dictated as inconclusive or nondiagnostic, technical parameters and study interpretation patterns should be scrutinized. Potential safety hazards for cCTA in the ED should be identified and proactive policies implemented to mitigate risk (Table 3). Since it is the program’s responsibility to ensure patients are not exposed to unnecessary radiation, we recommend monthly review of dose indices. Radiation doses should fall within target levels established by SCCT guidelines. Resources such as the ACR Dose Index Registry can facilitate automatic monitoring of radiation exposure with benchmarks for comparing a program to regional and national values [31]. The task force should collaborate closely with vendors and local physicists to optimize dose reduction strategies, including prospective ECG triggering and iterative reconstruction, while preserving image quality.

Curr Cardiovasc Imaging Rep (2015) 8: 21

To demonstrate the value of cCTA to a health care organization, the task force should collaborate with IT and billing departments to capture patient information and outcomes data for organization into a local cCTA registry. Local registries can facilitate quality improvement and research opportunities. Important information to capture in the registry includes: patient demographics, coronary stenosis and extent of disease from cCTA, disposition recommendations, time from initial ED triage to cCTA, time from initial ED triage to final diagnosis, total hospital length of stay, total ED costs, total hospital costs (including index visit and follow-up examinations), radiation exposure, downstream testing (including invasive coronary angiography), downstream coronary revascularizations (PCI and CABG), and health outcomes. The number of downstream invasive coronary angiograms which do not lead to coronary revascularization is a particularly important quality assurance metric that should be kept as low as possible to prevent overutilization of cardiac catheterization. While this quality assurance process may seem cumbersome, it is one of the most effective strategies for demonstrating the value of a cCTA program to a healthcare organization. Finally, barriers to success should be recognized, including those at the national level and local level (Table 4).

Conclusion Strong multidisciplinary collaboration, strategic planning, and standardized processes for workflow and quality assurance are essential ingredients for cCTA in the ED to thrive. The program should aim to deliver the highest level of patient care by following established guidelines and evidence-based practices. Once established, a cCTA program should market its value to the local healthcare system using quantifiable data from a local registry. A cCTA program should start slow, particularly during the initial months after implementation, but remain flexible to the needs of the ED. Effective communication and regular process monitoring will help maintain a successful cCTA program, potentially yielding significant cost savings and optimizing patient outcomes. Promising developments such as CT perfusion [28, 32] and CT-based fractional flow reserve (FFR-CT) [33] will likely expand the future role of cCTA in the ED.

Compliance with Ethics Guidelines Conflict of Interest CD Maroules, RC Cury, BB Ghoshhajra, U Hoffmann, HI Litt, R Blankstein, and S Abbara all declare no conflicts of interest. Human and Animal Rights and Informed Consent This article does not contain any studies with human or animal subjects performed by any of the authors.

Curr Cardiovasc Imaging Rep (2015) 8: 21

References Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance 1.

Bayley MD, Schwartz JS, Shofer FS, et al. The financial burden of emergency department congestion and hospital crowding for chest pain patients awaiting admission. Ann Emerg Med. 2005;45:110–7. 2. Schull MJ, Vermeulen M, Slaughter G, Morrison L, Daly P. Emergency department crowding and thrombolysis delays in acute myocardial infarction. Ann Emerg Med. 2004;44:577–85. 3. Samad Z, Hakeem A, Mahmood SS, et al. A meta-analysis and systematic review of computed tomography angiography as a diagnostic triage tool for patients with chest pain presenting to the emergency department. J Nucl Cardiol Off Publ Am Soc Nucl Cardiol. 2012;19:364–76. 4. Litt HI, Gatsonis C, Snyder B, et al. CT angiography for safe discharge of patients with possible acute coronary syndromes. N Engl J Med. 2012;366:1393–403. 5. Goldstein JA, Chinnaiyan KM, Abidov A, et al. The CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment) trial. J Am Coll Cardiol. 2011;58:1414–22. 6. Hoffmann U, Truong QA, Schoenfeld DA, et al. Coronary CT angiography versus standard evaluation in acute chest pain. N Engl J Med. 2012;367:299–308. 7. Truong QA, Hayden D, Woodard PK, et al. Sex differences in the effectiveness of early coronary computed tomographic angiography compared with standard emergency department evaluation for acute chest pain: the rule-out myocardial infarction with ComputerAssisted Tomography (ROMICAT)-II Trial. Circulation. 2013;127:2494–502. 8.•• Hulten E, Pickett C, Bittencourt MS, et al. Outcomes after coronary computed tomography angiography in the emergency department: a systematic review and meta-analysis of randomized, controlled trials. J Am Coll Cardiol. 2013;61:880–92. An in-depth and wellorganized meta-analysis and systematic review of randomized, controlled trials of cCTA versus usual care for evaluation of acute chest pain in the ED, this paper nicely summarizes the benefits and limitations of a cCTA-based approach. 9. Cury RC, Feuchtner GM, Batlle JC, et al. Triage of patients presenting with chest pain to the emergency department: implementation of coronary CT angiography in a large urban health care system. AJR Am J Roentgenol. 2013;200:57–65. 10. Nasis A, Meredith IT, Sud PS, Cameron JD, Troupis JM, Seneviratne SK. Long-term outcome after CT angiography in patients with possible acute coronary syndrome. Radiology. 2014;272:674–82. 11.• Schlett CL, Banerji D, Siegel E, et al. Prognostic value of CT angiography for major adverse cardiac events in patients with acute chest pain from the emergency department: 2-year outcomes of the ROMICAT trial. JACC. Cardiovasc Imaging. 2011;4:481–91. This article investigated the 2-year prognostic value of cCTA for predicting major adverse cardiac events among 368 patients from the ROMICAT trial who presented to the ED with acute chest pain. Investigators found the absence of coronary artery disease on cCTA provided a 2-year event-free warranty period. 12. Hollander JE, Chang AM, Shofer FS, et al. One-year outcomes following coronary computerized tomographic angiography for evaluation of emergency department patients with potential acute coronary syndrome. Acad Emerg Med Off J Soc Acad Emerg Med. 2009;16:693–8.

Page 9 of 10 21 13.• Hamilton-Craig C, Fifoot A, Hansen M, et al. Diagnostic performance and cost of CT angiography versus stress ECG–a randomized prospective study of suspected acute coronary syndrome chest pain in the emergency department (CT-COMPARE). Int J Cardiol. 2014;177:867–73. CT-COMPARE is the first randomized trial directly comparing cCTA to exercise stress ECG for the evaluation of low-intermediate risk acute chest pain. The authors report improved diagnostic performance with a cCTA-based approach, combined with reduced length-of-stay and lower hospital costs. 14. Maroules CD, Blaha MJ, El-Haddad MA, Ferencik M, Cury RC. Establishing a successful coronary CT angiography program in the emergency department: official writing of the Fellow and Resident Leaders of the Society of Cardiovascular Computed Tomography (FiRST). J Cardiovasc Comput Tomogr. 2013;7:150–6. 15. Budoff MJ, Achenbach S, Berman DS, et al. Task force 13: training in advanced cardiovascular imaging (computed tomography). J Cardiovasc Comput Tomogr. 2008;2:130–5. 16.•• Raff GL, Chinnaiyan KM, Cury RC, et al. SCCT guidelines on the use of coronary computed tomographic angiography for patients presenting with acute chest pain to the emergency department: a report of the Society of Cardiovascular Computed Tomography Guidelines Committee. J Cardiovasc Comput Tomogr. 2014;8: 254–71. The article features guidelines from the Society of Cardiovascular Computed Tomography (SCCT) for performance of cCTA in the emergency department for evaluation of acute chest pain. These guidelines serve as an important educational tool for physicians to standardize cCTA in the ED for improving patient care based on broad expert consensus and available data. 17. Hulten E, Goehler A, Bittencourt MS, et al. Cost and resource utilization associated with use of computed tomography to evaluate chest pain in the emergency department: the rule out myocardial infarction using computer assisted tomography (ROMICAT) study. Circ Cardiovasc Qual Outcomes. 2013;6:514–24. 18. Cheezum MK, Blankstein R. Coronary computed tomographic angiography: its role in emergency department triage. Circulation. 2014;130:2052–6. 19. Abbara S, Arbab-Zadeh A, Callister TQ, et al. SCCT guidelines for performance of coronary computed tomographic angiography: a report of the Society of Cardiovascular Computed Tomography Guidelines Committee. J Cardiovasc Comput Tomogr. 2009;3: 190–204. 20. Leipsic J, Abbara S, Achenbach S, et al. SCCT guidelines for the interpretation and reporting of coronary CT angiography: a report of the Society of Cardiovascular Computed Tomography Guidelines Committee. J Cardiovasc Comput Tomogr. 2014;8:342–58. 21. Halliburton SS, Abbara S, Chen MY, et al. SCCT guidelines on radiation dose and dose-optimization strategies in cardiovascular CT. J Cardiovasc Comput Tomogr. 2011;5:198–224. 22. Pannu HK, Alvarez Jr W, Fishman EK. Beta-blockers for cardiac CT: a primer for the radiologist. AJR Am J Roentgenol. 2006;186: S341–5. 23. Cury RC, Feuchtner G, Mascioli C, et al. Cardiac CT in the emergency department: convincing evidence, but cautious implementation. J Nucl Cardiol Off Publ Am Soc Nucl Cardiol. 2011;18:331– 41. 24. Taylor AJ, Cerqueira M, Hodgson JM, et al. ACCF/SCCT/ACR/ AHA/ASE/ASNC/NASCI/SCAI/SCMR 2010 appropriate use criteria for cardiac computed tomography. A report of the American College of Cardiology Foundation Appropriate Use Criteria Task Force, the Society of Cardiovascular Computed Tomography, the American College of Radiology, the American Heart Association, the American Society of Echocardiography, the American Society of Nuclear Cardiology, the North American Society for Cardiovascular Imaging, the Society for Cardiovascular

21 Page 10 of 10 Angiography and Interventions, and the Society for Cardiovascular Magnetic Resonance. J Am Coll Cardiol. 2010;56:1864–94. 25. Cheezum MK, Bittencourt MS, Hulten EA, Scirica BM, Villines TC, Blankstein R. Coronary computed tomographic angiography in the emergency room: state of the art. Expert Rev Cardiovasc Ther. 2014;12:241–53. 26. Bezerra HG, Loureiro R, Irlbeck T, et al. Incremental value of myocardial perfusion over regional left ventricular function and coronary stenosis by cardiac CT for the detection of acute coronary syndromes in high-risk patients: a subgroup analysis of the ROMICAT trial. J Cardiovasc Comput Tomogr. 2011;5:382–91. 27. Branch KR, Busey J, Mitsumori LM, et al. Diagnostic performance of resting CT myocardial perfusion in patients with possible acute coronary syndrome. AJR Am J Roentgenol. 2013;200:W450–7. 28. Pursnani A, Lee AM, Mayrhofer T, et al. Early resting myocardial computed tomography perfusion for the detection of acute coronary

Curr Cardiovasc Imaging Rep (2015) 8: 21 syndrome in patients with coronary artery disease. Circ Cardiovasc Imaging. 2015;8:e002404. 29. Lin FY, Dunning AM, Narula J, et al. Impact of an automated multimodality point-of-order decision support tool on rates of appropriate testing and clinical decision making for individuals with suspected coronary artery disease: a prospective multicenter study. J Am Coll Cardiol. 2013;62:308–16. 30. Staniak HL, Bittencourt MS, Pickett C, et al. Coronary CT angiography for acute chest pain in the emergency department. J Cardiovasc Comput Tomogr. 2014;8:359–67. 31. Morin RL, Coombs LP, Chatfield MB. ACR dose index registry. J Am Coll Radiol JACR. 2011;8:288–91. 32. Techasith T, Cury RC. Stress myocardial CT perfusion: an update and future perspective. JACC Cardiovasc Imaging. 2011;4:905–16. 33. Shantouf RS, Mehra A. Coronary fractional flow reserve. AJR Am J Roentgenol. 2015;204:W261–5.