Cardiovascular Imaging Research at the Crossroads

A comparison of cardiovascular imaging practices in Africa, North America, and Europe: two faces of the same coin

Cardiovascular diseases remain the leading cause of morbidity and mortality worldwide. There are significant differences in the burden of cardiovascular disease and associated risk factors, across high-income countries and low- and middle-income countries. Cardiac imaging by echocardiography, cardiac computed tomography, cardiac magnetic resonance imaging, single-photon emission computed tomography, and positron emission tomography myocardial perfusion imaging are well-established non-invasive tests that aid in the diagnosis, risk stratification, and management of various cardiac diseases. However, there are significant inequalities in availability and access to imaging modalities in low- and middle-income countries attributed to financial constraints, disparities in healthcare and technical infrastructure. In the post-COVID-19 pandemic era, these disparities are exaggerated by the continued technological advancements driving innovations in the field of cardiovascular (CV) imaging in high-income countries, while there is an urgent need to provide sustainable access to diagnostic imaging for patients in economically strained healthcare systems in regions like Africa. This review aims to highlight the inequalities in the burden of cardiac disease, associated risk factors, and access to diagnostic CV imaging tests, while also exploring the need for sustainable solutions to implementing CV imaging all over the world.

Cardiovascular positron emission tomography: established and emerging role in cardiovascular diseases

Cardiac positron emission tomography (PET) imaging has established themselves firmly as excellent and reliable functional imaging modalities in assessment of the spectrum of coronary artery disease. With the explosion of technology advances and the dream of flow quantification now a reality, the value of PET is now well realized. Cardiac PET has proved itself as precise imaging modality that provides functional imaging of the heart in addition to anatomical imaging. It has established itself as one of the best available techniques for evaluation of myocardial viability. Hybrid PET/computed tomography provides simultaneous integration of coronary anatomy and function with myocardial perfusion and metabolism, thereby improving characterization of the dysfunctional area and chronic coronary artery disease. The availability of quantitative myocardial blood flow evaluation with PET provides additional prognostic information and increases diagnostic accuracy in the management of patients with coronary artery disease. Hybrid imaging seems to hold immense potential in optimizing management of cardiovascular diseases and furthering clinical research.

Cardiac computed tomography radiomics: a narrative review of current status and future directions

BACKGROUND AND OBJECTIVE

In an era of profound growth of medical data and rapid development of advanced imaging modalities, precision medicine increasingly requires further expansion of what can be interpreted from medical images. However, the current interpretation of cardiac computed tomography (CT) images mainly depends on subjective and qualitative analysis. Radiomics uses advanced image analysis to extract numerous quantitative features from digital images that are unrecognizable to the naked eye. Visualization of these features can reveal underlying connections between image phenotyping and biological characteristics and support clinical outcomes. Although research into radiomics on cardiovascular disease began only recently, several studies have indicated its potential clinical value in assessing future cardiac risk and guiding prevention and management strategies. Our review aimed to summarize the current applications of cardiac CT radiomics in the cardiovascular field and discuss its advantages, challenges, and future directions.

METHODS

We searched for English-language articles published between January 2010 and August 2021 in the databases of PubMed, Embase, and Google Scholar. The keywords used in the search included computed tomography or CT, radiomics, cardiovascular or cardiac.

KEY CONTENT AND FINDINGS

The current applications of radiomics in cardiac CT were found to mainly involve research into coronary plaques, perivascular adipose tissue (PVAT), myocardial tissue, and intracardiac lesions. Related findings on cardiac CT radiomics suggested the technique can assist the identification of vulnerable plaques or patients, improve cardiac risk prediction and stratification, discriminate myocardial pathology and etiologies behind intracardiac lesions, and offer new perspective and development prospects to personalized cardiovascular medicine.

CONCLUSIONS

Cardiac CT radiomics can gather additional disease-related information at a microstructural level and establish a link between imaging phenotyping and tissue pathology or biology alone. Therefore, cardiac CT radiomics has significant clinical implications, including a contribution to clinical decision-making. Along with advancements in cardiac CT imaging, cardiac CT radiomics is expected to provide more precise phenotyping of cardiovascular disease for patients and doctors, which can improve diagnostic, prognostic, and therapeutic decision making in the future.

Effects of an Electronic Medical Record Intervention on Appropriateness of Transthoracic Echocardiograms: A Prospective Study

BACKGROUND

Transthoracic echocardiograms (TTEs) account for approximately half of U.S. spending on cardiac imaging. We developed an electronic medical record (EMR)-based decision-support algorithm for TTE ordering and hypothesized that it would increase the appropriateness of TTE orders.

METHODS

This prospective observational study was performed at the Veterans Affairs Ann Arbor Healthcare System. From October to December 2016 (preintervention), consecutive TTEs ordered in the inpatient, outpatient, and emergency department settings were included. In May 2017, a decision-support algorithm was incorporated into the EMR, giving immediate feedback to providers. Chart review was performed for TTEs ordered from June to August 2017 (early intervention) and from June to August 2018 (late intervention). Appropriateness was determined based on the 2011 appropriate use criteria for echocardiography.

RESULTS

Appropriate TTE orders increased from 87.6% preintervention to 94.5% at early intervention (z = 0.00018) but decreased to 90.0% at late intervention (z = 0.51, compared with preintervention). Among patients with no previous TTEs in our system, 95.3% of TTEs were appropriate, compared with 87.7% of TTEs for patients with prior TTEs within 30 days prior (odds ratio = 2.85; 95% CI, 1.18-6.31; P = .005).

CONCLUSIONS

The EMR algorithm initially increased the percentage of appropriate TTEs, but this effect decayed over time. Further study is needed to develop EMR-based interventions that will have lasting impacts on provider ordering patterns.

The cardiac conundrum: a systematic review and bibliometric analysis of authorship in cardiac magnetic resonance imaging studies

PURPOSE

We aimed to assess the role of radiologists, cardiologists, and other medical and non-medical figures in cardiac magnetic resonance imaging (MRI) research in the last 34 years, focusing on first and last authorship, number of published studies, and journal impact factors (IF).

METHODS

Articles in the field of cardiac MRI were considered in this systematic review and retrospective bibliometric analysis. For included studies, the first and last authors were categorized as cardiologists, radiologists/nuclear medicine physicians, medical doctors (MD) with specialties in both cardiology and radiology/nuclear medicine, and other MD and non-MD. Differences in the number of papers published overall and by year and institution location for the first and last author category were assessed. Mean IF differences between author categories were also investigated.

RESULTS

A total of 2053 articles were included in the final analysis. For the first authors (n = 2011), 52% were cardiologists, 22% radiologists/nuclear medicine physicians, 16% other MD, 10% other non-MD, and 1% both cardiologists and radiologists/nuclear medicine physicians. Similarly, the last authors (n = 2029) resulted 54% cardiologists, 22% radiologists/nuclear medicine physicians, 15% other MD, 8% other non-MD, and 2% both cardiologists and radiologists/nuclear medicine physicians. No significant differences due to institution location in the first and last authorship proportions were found. Average journal IF was significantly higher for cardiologist first and last authors when compared to that of radiologists/nuclear medicine physicians (both p < 0.0001).

CONCLUSION

Over 50% of studies in the field of cardiac MRI published in the last 34 years are conducted by cardiologists.

Is Physiologic Stress Test with Imaging Comparable to Anatomic Examination of Coronary Arteries by Coronary Computed Tomography Angiography to Investigate Coronary Artery Disease? - A Systematic Review and Meta-Analysis

Objective Coronary computed tomography angiography (CCTA) is a noninvasive diagnostic modality that remains underutilized compared to functional stress testing (ST) for investigating coronary artery disease (CAD). Several patients are misdiagnosed with noncardiac chest pain (CP) that eventually die from a cardiovascular event in subsequent years. We compared CCTA to ST to investigate CP. Methods We searched MEDLINE, PubMed, Cochrane Library, and Embase from January 1, 2007 to July 1, 2018 for randomized controlled trials (RCTs) comparing CCTA to ST in patients who presented with acute or stable CP. We used Review Manager (RevMan) [Computer program] Version 5.3 (Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014) for review and analysis. Results We included 16 RCTs enrolling 21,210 patients; there were more patients with hyperlipidemia and older patients in the ST arm compared to the CCTA arm. There was no difference in mortality: 103 in the CCTA arm vs. 110 in the ST arm (risk ratio [RR] = 0.93, 95% confidence interval [CI] = 0.71-1.21, P = .58, and I² = 0%). A significant reduction was seen in myocardial infarctions (MIs) after CCTA compared to ST: 115 vs. 156 (RR = 0.71, CI = 0.56-0.91, P < .006, I²=0%). On subgroup analysis, the CCTA arm had fewer MIs vs. the ST with imaging subgroup (RR = 0.70, CI = 0.54-0.89, P = .004, I² = 0%) and stable CP subgroup (RR = 0.66, CI = 0.50-0.88, P = .004, I² = 0%). The CCTA arm showed significantly higher invasive coronary angiograms and revascularizations and significantly reduced follow-up testing and recurrent hospital visits. A trend towards increased unstable anginas was seen in the CCTA arm. Conclusions Our analysis showed a significant reduction in downstream MIs, hospital visits, and follow-up testing when CCTA is used to investigate CAD with no difference in mortality.

Positron Emission Tomography in the Diagnosis and Management of Coronary Artery Disease

Cardiac positron emission tomography (PET) and positron emission tomography/computed tomography (PET/CT) are encouraging precise non-invasive imaging modalities that allow imaging of the cellular function of the heart, while other non-invasive cardiovascular imaging modalities are considered to be techniques for imaging the anatomy, morphology, structure, function and tissue characteristics. The role of cardiac PET has been growing rapidly and providing high diagnostic accuracy of coronary artery disease (CAD). Clinical cardiology has established PET as a criterion for the assessment of myocardial viability and is recommended for the proper management of reduced left ventricle (LV) function and ischemic cardiomyopathy. Hybrid PET/CT imaging has enabled simultaneous integration of the coronary anatomy with myocardial perfusion and metabolism and has improved characterization of dysfunctional areas in chronic CAD. Also, the availability of quantitative myocardial blood flow (MBF) evaluation with various PET perfusion tracers provides additional prognostic information and enhances the diagnostic performance of nuclear imaging.

Role of Cardiac PET in Clinical Practice

OPINION STATEMENT

Early identification of atherosclerosis and at-risk lesions plays a critical role in reducing the burden of cardiovascular disease. While invasive coronary angiography serves as the gold standard for diagnosing coronary artery disease, non-invasive imaging techniques provide visualization of both anatomical and functional atherosclerotic processes prior to clinical presentation. The development of cardiac positron emission tomography (PET) has greatly enhanced our capability to diagnose and treat patients with early stages of atherosclerosis. Cardiac PET is a powerful, versatile non-invasive diagnostic tool with utility in the identification of high-risk plaques, myocardial perfusion defects, and viable myocardial tissue. Cardiac PET allows for comparisons of myocardial function both at time of rest and stress, providing accurate assessments of both myocardial perfusion and viability. Furthermore, novel PET techniques with unique radiotracers yield clinically relevant data on high-risk plaques in active progressive atherosclerosis. While PET exercise stress tests were previously difficult to perform given short radiotracer half-life, the development of the novel radiotracer Flurpiridaz F-18 provides a promising future for PET exercise stress imaging. In addition, hybrid imaging with computed tomography angiography (CTA) and cardiac magnetic resonance (CMR) provides integration of cardiac function and structure. In this review article, we discuss the principles of cardiac PET, the clinical applications of PET in diagnosing and prognosticating patients at risk for future cardiovascular events, compare PET with other non-invasive cardiac imaging modalities, and discuss future applications of PET in CVD evaluation and management.

Cost-effectiveness of diagnostic evaluation strategies for individuals with stable chest pain syndrome and suspected coronary artery disease

PURPOSE

To determine lifetime cost-effectiveness of diagnostic evaluation strategies for individuals with stable chest pain and suspected coronary artery disease (CAD).

METHODS

Exercise treadmill testing (ETT), stress echocardiography (SE), myocardial perfusion scintigraphy (MPS), coronary computed tomographic angiography (CCTA), and invasive coronary angiography (ICA) were assessed alone, or in succession to each other.

RESULTS

Initial ETT followed by imaging wherein ETT was equivocal or unable to be performed appeared more cost-effective than any strategy employing initial testing by imaging.

CONCLUSION

As pre-test likelihood of CAD varies, different modalities including SE, CCTA, and MPS result in improved costs and enhanced effectiveness.

Diagnostic Strategies for the Evaluation of Chest Pain: Clinical Implications From SCOT-HEART and PROMISE

SCOT-HEART (Scottish COmputed Tomography of the HEART) and PROMISE (PROspective Multicenter Imaging Study for Evaluation of chest pain) represent the 2 largest and most comprehensive cardiovascular imaging outcome trials in patients with stable chest pain and provide significant insights into patient diagnosis, management, and outcomes. These trials are particularly timely, given the well-recognized knowledge gaps and widespread use of noninvasive imaging. The overall goal of this review is to distill the data generated from these 2 pivotal trials to better inform the practicing clinician in the selection of noninvasive testing for stable chest pain. Similarities and differences between SCOT-HEART and PROMISE are highlighted, and clinical and practical implications are discussed. Both trials show that coronary computed tomography angiography should have a greater role in the diagnostic pathway of patients with stable chest pain.

Costs and clinical outcomes for non-invasive versus invasive diagnostic approaches to patients with suspected in-stent restenosis

This study compared costs and clinical outcomes of invasive versus non-invasive diagnostic evaluations for patients with suspected in-stent restenosis (ISR) after percutaneous coronary intervention. We developed a decision model to compare 2 year diagnosis-related costs for patients who presented with suspected ISR and were evaluated by: (1) invasive coronary angiography (ICA); (2) non-invasive stress testing strategy of myocardial perfusion imaging (MPI) with referral to ICA based on MPI; (3) coronary CT angiography-based testing strategy with referral to ICA based on CCTA. Costs were modeled from the payer's perspective using 2014 Medicare rates. 56 % of patients underwent follow-up diagnostic testing over 2 years. Compared to ICA, MPI (98.6 %) and CCTA (98.1 %) exhibited lower rates of correct diagnoses. Non-invasive strategies were associated with reduced referrals to ICA and costs compared to an ICA-based strategy, with diagnostic costs lower for CCTA than MPI. Overall 2-year costs were highest for ICA for both metallic as well as BVS stents ($1656 and $1656, respectively) when compared to MPI ($1444 and $1411) and CCTA. CCTA costs differed based upon stent size and type, and were highest for metallic stents >3.0 mm followed by metallic stents <3.0 mm, BVS < 3.0 mm and BVS > 3.0 mm ($1466 vs. $1242 vs. $855 vs. $490, respectively). MPI for suspected ISR results in lower costs and rates of complications than invasive strategies using ICA while maintaining high diagnostic performance. Depending upon stent size and type, CCTA results in lower costs than MPI.

Clinical Applications of Myocardial Innervation Imaging

Cardiac autonomic innervation plays an important role in regulating function. Adrenergic innervation imaging is possible with the norepinephrine analogue radiotracer iodine 123 meta-iodobenzylguanidine ((123)I-mIBG) and positron emitting tracers such carbon-11 hydroxyephedrine. (123)I-mIBG uptake is assessed globally via the heart to mediastinum ratio on planar images and regionally with tomographic imaging and has utility in various cardiac diseases. There is promise for guiding expensive invasive therapies such as implantable defibrillators, ventricular assist devices, and transplant. There are reports of utility in primary arrhythmic conditions, ischemic heart disease, and diabetes and after cardiac damaging chemotherapy.

Design and methods of the Echo WISELY (Will Inappropriate Scenarios for Echocardiography Lessen SignificantlY) study: An investigator-blinded randomized controlled trial of education and feedback intervention to reduce inappropriate echocardiograms

BACKGROUND

Appropriate use criteria (AUC) for transthoracic echocardiography (TTE) were developed to address concerns regarding inappropriate use of TTE. A previous pilot study suggests that an educational and feedback intervention can reduce inappropriate TTEs ordered by physicians in training. It is unknown if this type of intervention will be effective when targeted at attending level physicians in a variety of clinical settings.

AIMS

The aim of this international, multicenter study is to evaluate the hypothesis that an AUC-based educational and feedback intervention will reduce the proportion of inappropriate echocardiograms ordered by attending physicians in the ambulatory environment.

METHODS

In an ongoing multicentered, investigator-blinded, randomized controlled trial across Canada and the United States, cardiologists and primary care physicians practicing in the ambulatory setting will be enrolled. The intervention arm will receive (1) a lecture outlining the AUC and most recent available evidence highlighting appropriate use of TTE, (2) access to the American Society of Echocardiography mobile phone app, and (3) individualized feedback reports e-mailed monthly summarizing TTE ordering behavior including information on inappropriate TTEs and brief explanations of the inappropriate designation. The control group will receive no education on TTE appropriate use and order TTEs as usual practice.

CONCLUSIONS

The Echo WISELY (Will Inappropriate Scenarios for Echocardiography Lessen Significantly in an education RCT) study is the first multicenter randomized trial of an AUC-based educational intervention. The study will examine whether an education and feedback intervention will reduce the rate of outpatient inappropriate TTEs ordered by attending level cardiologists and primary care physicians (www.clinicaltrials.gov identifier NCT02038101).

Outcomes of anatomical versus functional testing for coronary artery disease

BACKGROUND

Many patients have symptoms suggestive of coronary artery disease (CAD) and are often evaluated with the use of diagnostic testing, although there are limited data from randomized trials to guide care.

METHODS

We randomly assigned 10,003 symptomatic patients to a strategy of initial anatomical testing with the use of coronary computed tomographic angiography (CTA) or to functional testing (exercise electrocardiography, nuclear stress testing, or stress echocardiography). The composite primary end point was death, myocardial infarction, hospitalization for unstable angina, or major procedural complication. Secondary end points included invasive cardiac catheterization that did not show obstructive CAD and radiation exposure.

RESULTS

The mean age of the patients was 60.8±8.3 years, 52.7% were women, and 87.7% had chest pain or dyspnea on exertion. The mean pretest likelihood of obstructive CAD was 53.3±21.4%. Over a median follow-up period of 25 months, a primary end-point event occurred in 164 of 4996 patients in the CTA group (3.3%) and in 151 of 5007 (3.0%) in the functional-testing group (adjusted hazard ratio, 1.04; 95% confidence interval, 0.83 to 1.29; P=0.75). CTA was associated with fewer catheterizations showing no obstructive CAD than was functional testing (3.4% vs. 4.3%, P=0.02), although more patients in the CTA group underwent catheterization within 90 days after randomization (12.2% vs. 8.1%). The median cumulative radiation exposure per patient was lower in the CTA group than in the functional-testing group (10.0 mSv vs. 11.3 mSv), but 32.6% of the patients in the functional-testing group had no exposure, so the overall exposure was higher in the CTA group (mean, 12.0 mSv vs. 10.1 mSv; P<0.001).

CONCLUSIONS

In symptomatic patients with suspected CAD who required noninvasive testing, a strategy of initial CTA, as compared with functional testing, did not improve clinical outcomes over a median follow-up of 2 years. (Funded by the National Heart, Lung, and Blood Institute; PROMISE ClinicalTrials.gov number, NCT01174550.).

External validation of models for estimating pretest probability of coronary artery disease among individuals undergoing myocardial perfusion imaging

BACKGROUND

Clinical decisions regarding the appropriateness of noninvasive cardiac imaging among individuals with suspected coronary artery disease (CAD) rely heavily on the pretest probability of coronary artery disease (pCAD), often estimated from clinical prediction models. These models have not been validated among individuals undergoing noninvasive myocardial perfusion imaging (MPI) for suspected CAD. Thus, the objective of this study was to compare the extent of agreement and predictive performance between four published pCAD models among individuals undergoing positron emission tomography (PET MPI).

METHODS

This cross-sectional study performed at a cardiac referral center included 2383 patients with stable symptoms undergoing PET MPI for the evaluation of suspected CAD. pCAD was estimated on a per-patient basis using four distinct pCAD estimation models. All pCAD estimates were calibrated to a common standard to allow fair comparisons of agreement and predictive performance. Pairwise pCAD model disagreement was defined as percent discordance in classifying patients as low versus intermediate pCAD (<10% vs. ≥10%). Predictive performance was quantified by c-statistics with abnormal myocardial perfusion as a binary outcome.

RESULTS

Pairwise pCAD estimates demonstrated non-negligible disagreement with percent discordance between models ranging from 11% to 23%. Agreement worsened when higher thresholds for distinguishing low-intermediate pCAD were employed. All pCAD models demonstrated poor predictive performance for identifying abnormal stress perfusion with c-statistics ranging from 0.554 to 0.616.

CONCLUSIONS

pCAD estimation models showed suboptimal agreement and poor predictive performance in patients undergoing PET MPI. The transportability of pCAD models to MPI patients should be questioned and further evaluated in future studies.

Hospital-level variation in use of cardiovascular testing for adults with incident heart failure: findings from the cardiovascular research network heart failure study

OBJECTIVES

This study aimed to characterize the use of cardiovascular testing for patients with incident heart failure (HF) hospitalization who participated in the National Heart, Lung, and Blood Institute sponsored Cardiovascular Research Network (CVRN) Heart Failure study.

BACKGROUND

HF is a common cause of hospitalization, and testing and treatment patterns may differ substantially between providers. Testing choices have important implications for the cost and quality of care.

METHODS

Crude and adjusted cardiovascular testing rates were calculated for each participating hospital. Cox proportional hazards regression models were used to examine hospital testing rates after adjustment for hospital-level patient case mix.

RESULTS

Of the 37,099 patients in the CVRN Heart Failure study, 5,878 patients were hospitalized with incident HF between 2005 and 2008. Of these, evidence of cardiovascular testing was available for 4,650 (79.1%) patients between 14 days before the incident HF admission and ending 6 months after the incident discharge. We compared crude and adjusted cardiovascular testing rates at the hospital level because the majority of testing occurred during the incident HF hospitalization. Of patients who underwent testing, 4,085 (87.9%) had an echocardiogram, 4,345 (93.4%) had a systolic function assessment, and 1,714 (36.9%) had a coronary artery disease assessment. Crude and adjusted testing rates varied markedly across the profiled hospitals, for individual testing modalities (e.g., echocardiography, stress echocardiography, nuclear stress testing, and left heart catheterization) and for specific clinical indications (e.g., systolic function assessment and coronary artery disease assessment).

CONCLUSIONS

For patients with newly diagnosed HF, we did not observe widespread overuse of cardiovascular testing in the 6 months following incident HF hospitalization relative to existing HF guidelines. Variations in testing were greatest for assessment of ischemia, in which testing guidelines are less certain.

Cost-effectiveness analysis for imaging techniques with a focus on cardiovascular magnetic resonance

With the need for healthcare cost-containment, increased scrutiny will be placed on new medical therapeutic or diagnostic technologies. Several challenges exist for a new diagnostic test to demonstrate cost-effectiveness. New diagnostic tests differ from therapeutic procedures due to the fact that diagnostic tests do not generally directly affect long-term patient outcomes. Instead, the results of diagnostic tests can influence management decisions for patients and by this route, diagnostic tests indirectly affect long-term outcomes. The benefits from a specific diagnostic technology depend therefore not only on its performance characteristics, but also on other factors such as prevalence of disease, and effectiveness of existing treatments for the disease of interest. We review the concepts and theories of cost-effectiveness analyses (CEA) as they apply to diagnostic tests in general. The limitations of CEA across different study designs and geographic regions are discussed, and we also examine the strengths and weakness of the existing publications where CMR was the focus of CEA compared to other diagnostic options.

Usefulness of exercise test and myocardial perfusion-gated single photon emission computed tomography to improve the prediction of major events

BACKGROUND

The incremental prognostic value of myocardial perfusion-gated single photon emission computed tomography (MPGS) compared with exercise test has not yet been properly evaluated.

METHODS AND RESULTS

Five thousand six hundred seventy-two consecutive patients with known or suspected coronary disease undergoing exercise MPGS between 1997 and 2007 were included. Three-year predictive models for total death and death from cardiovascular causes or acute myocardial infarction (ie, major cardiovascular events [MCE]) were built using Cox-regression modeling, including only the clinical information. Then the exercise and MPGS information was sequentially added. The added discriminative ability of exercise test information and MPGS was assessed by net reclassification improvement and integrated discrimination improvement. The increase in predictive ability of exercise information for death and MCE was high as assessed by net reclassification improvement (0.199 and 0.263) and integrated discrimination improvement (0.042 and 0.021). The only variable of MPGS associated with total death was ejection fraction (hazard ratio, 0.84; 95% confidence interval, 0.79-0.89; P<0.001). Global stress ischemic score emerged as an additional variable associated with MCE (hazard ratio, 1.07; 95% confidence interval, 1.02-1.12; P=0.007). Adding MPGS information barely improved the prognostic value for total death (net reclassification improvement, 0.017; integrated discrimination improvement, 0.013), but it increased for MCE (net reclassification improvement, 0.122; integrated discrimination improvement, 0.033).

CONCLUSIONS

Adding MPGS information to exercise information does not improve prediction of total death, although it allows a more accurate prediction of MCE.

An educational intervention reduces the rate of inappropriate echocardiograms on an inpatient medical service

OBJECTIVES

This study sought to prospectively study the impact of an appropriate use criteria (AUC)-based educational intervention on transthoracic echocardiography (TTE) ordering among house staff on the inpatient general internal medicine service at an academic medical center.

BACKGROUND

AUC for TTE were developed in response to concerns about inappropriate use of TTE. To date, educational interventions based on the AUC to reduce inappropriate use of TTE have not been prospectively studied.

METHODS

A prospective, time series analysis of an educational intervention was conducted and then compared with TTE ordering on the same medical service during a control period. The intervention consisted of: 1) a lecture to house staff on the 2011 AUC for TTE; 2) a pocket card that applied the AUC to common clinical scenarios; and 3) biweekly e-mail feedback regarding ordering behavior. TTE ordering was tracked over the intervention period on a daily basis and feedback reports were e-mailed at 2-week intervals. The primary outcome was the proportion of inappropriate and appropriate TTE ordered during the intervention period.

RESULTS

Of all TTEs ordered in the control and study periods, 99% and 98%, respectively, were classifiable using the 2011 AUC. During the study period, there was a 26% reduction in the number of TTE ordered per day compared with the number ordered during the control period (2.9 vs. 3.9 TTE, p < 0.001). During the study period, the proportion of inappropriate TTE was significantly lower (5% vs. 13%, p < 0.001) and the proportion of appropriate TTE was significantly higher (93% vs. 84%, p < 0.001).

CONCLUSIONS

A simple educational intervention produced a significant reduction in the proportion of inappropriate TTE and increased the proportion of appropriate TTE ordered on an inpatient academic medical service. This study provides a practical approach for using the AUC to reduce the number of inappropriate TTE. Further study in other practice environments is warranted.

Comparison of the 2006 and 2010 cardiac CT appropriateness criteria in a real-world setting

BACKGROUND

Coronary CT angiography (CCTA) is a relatively new technique whose role has yet to be fully defined. The initial appropriateness criteria (AC) guidelines published in 2006 have already been revised. There is paucity of data on the effect of the AC on the use of CCTA at academic centers and none for the private sector.

METHODS

All CCTA studies ordered at one institution (a large community hospital with internal medicine and cardiovascular training programs) from 2006 to 2008 were retrospectively evaluated, and the ordering indications were categorized per the published AC for both 2006 and 2010.

RESULTS

There were 384 studies, of which 243 were included in this study. The majority of the studies were ordered for chest pain (67.1% of patients). A significant proportion of studies (43.2%) were classified as inappropriate on the basis of the 2006 published criteria. Uncertain indications made up 39.1%, and appropriate indications were a minority. There was a significant regrading of appropriateness using the 2010 guidelines. Inappropriate testing remained similar at 48.1%, but uncertain cases decreased to only 2.8%, while appropriateness increased to 49.0% (P = .0001 for trend).

CONCLUSIONS

The updated 2010 AC guidelines for CCTA resulted in a significant reclassification of the indications for ordering CCTA from the previous 2006 guidelines. This shift in the AC reflects increased familiarity and confidence with this new technology across the imaging community. A large proportion of CCTA studies were ordered for inappropriate indications using both sets of criteria. Further research and enhanced education are needed to disseminate the appropriate role of CCTA in cardiovascular imaging.

Cost-effectiveness and future implications for cardiovascular imaging

This review highlights the current economic climate for health care and the evidentiary standards that are increasingly applied to appropriate use of cardiovascular imaging. Additionally, the evidence on cost efficiency and effectiveness is explored in this review. Ongoing multicentre registries and clinical trials will further enrich this evidence base with regard to value-based imaging strategies that provide enhanced effectiveness and efficiency resulting in improved patient outcomes.