Cost-Effectiveness of Coronary MDCT in the Triage of Patients with Acute Chest Pain

Cost-utility of computed tomography in patients with atypical chest pain clinically referred for invasive coronary angiography: randomised controlled trial

BACKGROUND

Computed tomography (CT) is as safe as invasive coronary angiography (ICA) in the incidence of major adverse cardiovascular events in patients with atypical chest pain. However, the cost-utility of CT and ICA in healthcare after long-term follow-up is still unknown.

METHODS

A prespecified cost-utility analysis (CUA) of 329 patients with atypical chest pain from a single-centre randomised trial compared CT and ICA. The CUA was conducted from the health sector perspective up to a 3-year follow-up using quality-adjusted life years (QALYs) from the EQ-5D-3L questionnaire. Costs were obtained from each individual's outpatient and inpatient billing data and included cardiovascular medications, hospitalisations, emergency visits, cardiologist visits, and cardiac examinations. The analysis implemented 500 multiple imputations and 1000 bootstrapping iterations per imputed dataset, followed by calculating the net monetary benefit (NMB).

RESULTS

There was no significant difference in mean QALYs at either 1-year (CT: 0.69 (95% CI: 0.66-0.72); ICA: 0.71 (95% CI: 0.68-0.74); difference: -0.02 (-0.06 to 0.03)) or 3-year follow-up (CT: 2.09 (95% CI: 2.00-2.17); ICA: 2.11 (95% CI: 2.02-2.19); difference: -0.02 (95% CI: -0.14 to 0.12)), while the mean cost per patient was significantly lower in the CT compared with the ICA at both 1-year (difference (€): -1647.8, 95% CI: -2198.3 to 1093.3) and at 3-year follow-ups (difference (€): -1543.3, 95% CI: -2228.0 to -830.0). At a willingness-to-pay of €20,000/QALY, the mean incremental NMB of CT over ICA was €1256.5 (164.8-2331.8) at 1-year and €1202.0 (95% CI: -1378.7 to -3961) at 3-year follow-ups.

CONCLUSION

A CT-first strategy for the management of patients with atypical angina or chest pain was more cost-effective than a direct ICA strategy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00844220.

KEY POINTS

Question What is the cost-effectiveness of using CT compared to invasive coronary angiography (ICA) for diagnosing coronary artery disease in patients with atypical chest pain? Findings A CT-first diagnostic strategy was €1543 less costly per patient over a 3-year follow-up, yielding similar quality-adjusted life years compared to ICA. Clinical relevance CT offers a cost-effective, non-invasive alternative to ICA for patients with atypical chest pain, reducing healthcare costs significantly without compromising patient-reported outcomes or quality of life.

Use of Coronary CTA to Triage Patients With Low to Intermediate Risk for CADs in an Acute Care Facility Can Help Lower Healthcare Costs When Compared With the Current Standard of Care: A Retrospective Study

Acute chest pain is one of the most common reasons for ED visits in the United States. Most patients are eventually admitted to the hospital to "rule out ACS" even when there are no significant EKG abnormalities or elevated cardiac enzymes. In addition to undergoing expensive tests while in the hospital, patients are also exposed to iatrogenic harm thereby worsening the overall healthcare costs. Meanwhile, the use of coronary computed tomography angiography (CTA) as a "gatekeeper" diagnostic test for patients with low to intermediate risk for coronary artery diseases (CADs) has significantly lowered hospital admissions and associated costs. However, coronary CTA may not be helpful for all classes of patients. Therefore, this study seeks to determine if the distribution of patients presenting to the ED with chest pain in an acute care facility will justify an investment in coronary CTA and contribute to lowering healthcare costs. Patients' data between July 2022 and June 2023 were considered in our analysis. Results revealed that a significant number of patients who presented to the ED for chest pain and were subsequently admitted to the hospital for further work-up would have benefited from coronary CTA screening without any need for further inpatient work-up. Also, cost analysis showed that the use of coronary CTA would have helped significantly lower healthcare costs in this facility.

FFRct use for acute chest pain triage in the emergency department: a cost-effectiveness analysis

AIMS

To model and assess the cost-effectiveness of CT-based fractional flow reserve (FFRct) for a population of low to intermediate risk patients for coronary artery disease (CAD) presenting to the emergency department (ED) with acute chest pain.

METHODS AND RESULTS

Using a decision tree model with a 1 year time horizon and from a health care perspective, two diagnostic pathways using FFRct are compared to current clinical routine combining coronary computed tomography angiography (CCTA) with an exercise test. Model data are drawn from the literature and nationally reported data. Outcomes are assessed as the number of avoided invasive coronary angiographies (ICAs) showing no obstructive CAD and quality of life (QoL) in a theoretical cohort of 1000 patients. Sensitivity analyses are performed to test the robustness of the results. Determining FFRct when CCTA is inconclusive is a cost-effective and dominant strategy with a potential saving of 198€/patient, 154 avoided unnecessary ICA showing no obstructive CAD (uICA)/1000 patients and an average improvement in QoL of 0.008 QALY/patient. With an additional 574€/patient, 8 avoided uICA/1000 patients and an improvement in QoL of 0.001 QALY/patient, a strategy where FFRct is always performed is cost-effective only when considering high cost-effectiveness thresholds.

CONCLUSIONS

For patients presenting to the ED with acute chest pain and a low to intermediate pre-test probability of CAD, a diagnostic strategy where FFRct is determined after an inconclusive CCTA is cost-effective. Clinical trials investigating both sensitivity and specificity of FFRct, as well as QoL associated with the use of this technology in this setting are warranted.

The Cost Effectiveness of Coronary CT Angiography and the Effective Utilization of CT-Fractional Flow Reserve in the Diagnosis of Coronary Artery Disease

Given the high global disease burden of coronary artery disease (CAD), a major problem facing healthcare economic policy is identifying the most cost-effective diagnostic strategy for patients with suspected CAD. The aim of this review is to assess the long-term cost-effectiveness of coronary computed tomography angiography (CCTA) when compared with other diagnostic modalities and to define the cost and effective diagnostic utilization of computed tomography-fractional flow reserve (CT-FFR). A search was conducted through the MEDLINE database using PubMed with 16 of 119 manuscripts fitting the inclusion and exclusion criteria for review. An analysis of the data included in this review suggests that CCTA is a cost-effective strategy for both low risk acute chest pain patients presenting to the emergency department (ED) and low-to-intermediate risk stable chest pain outpatients. For patients with intermediate-to-high risk, CT-FFR is superior to CCTA in identifying clinically significant stenosis. In low-to-intermediate risk patients, CCTA provides a cost-effective diagnostic strategy with the potential to reduce economic burden and improve long-term health outcomes. CT-FFR should be utilized in intermediate-to-high risk patients with stenosis of uncertain clinical significance. Long-term analysis of cost-effectiveness and diagnostic utility is needed to determine the optimal balance between the cost-effectiveness and diagnostic utility of CT-FFR.

Long-term health outcomes and cost-effectiveness of coronary CT angiography in patients with suspicion for acute coronary syndrome

BACKGROUND

Randomized trials have shown favorable clinical outcomes for coronary CT angiography (CTA) in patients with suspected acute coronary syndrome (ACS). Our goal was to estimate the cost-effectiveness of coronary CTA as compared to alternative management strategies for ACP patients over lifetime.

METHODS

Markov microsimulation model was developed to compare cost-effectiveness of competitive strategies for ACP patients: 1) coronary CTA, 2) standard of care (SOC), 3) AHA/ACC Guidelines, and 4) expedited emergency department (ED) discharge protocol with outpatient testing. ROMICAT-II trial was used to populate the model with low to intermediate risk of ACS patient data, whereas diagnostic test-, treatment effect-, morbidity/mortality-, quality of life- and cost data were obtained from the literature. We predicted test utilization, costs, 1-, 3-, 10-year and over lifetime cardiovascular morbidity/mortality for each strategy. We determined quality adjusted life years (QALY) and incremental cost-effectiveness ratio. Observed outcomes in ROMICAT-II were used to validate the short-term model.

RESULTS

Estimated short-term outcomes accurately reflected observed outcomes in ROMICAT-II as coronary CTA was associated with higher costs ($4,490 vs. $2,513-$4,144) and revascularization rates (5.2% vs. 2.6%-3.7%) compared to alternative strategies. Over lifetime, coronary CTA dominated SOC and ACC/AHA Guidelines and was cost-effective compared to expedited ED protocol ($49,428/QALY). This was driven by lower cardiovascular mortality (coronary CTA vs. expedited discharge: 3-year: 1.04% vs. 1.10-1.17; 10-year: 5.06% vs. 5.21-5.36%; respectively).

CONCLUSION

Coronary CTA in patients with suspected ACS renders affordable long-term health benefits as compared to alternative strategies.

Percutaneous Coronary Intervention Versus Optimal Medical Therapy for Stable Angina in Advanced CKD: A Decision Analysis

BACKGROUND

Percutaneous coronary intervention (PCI) use is low in the setting of stable symptomatic angina in individuals with advanced chronic kidney disease (CKD) despite high cardiovascular risk in this population, and PCI is frequently deferred out of concern for precipitating dialysis therapy. Whether this is appropriate is uncertain, and patient-centered data comparing the relative risks and benefits of continued medical therapy versus PCI in patients with advanced CKD and stable angina are scarce.

STUDY DESIGN

Decision analysis.

SETTING & POPULATION

Hypothetical cohort of individuals with advanced CKD (stages 4-5 with estimated glomerular filtration rates ≤ 20mL/min/1.73m2) and stable angina.

MODEL, PERSPECTIVE, & TIMELINE

A Markov model with a Monte Carlo simulation through 12 cycles, that is, 3 years of 3-month intervals, with 10,000 microsimulations predicted mean quality-adjusted life-years.

INTERVENTION

PCI first, medical management, or dialysis (hemodialysis [HD]) followed by PCI.

OUTCOMES

Outcomes modeled were progression to HD therapy (for those not assigned to the preemptive HD strategy), catheter infection, and death.

RESULTS

Our analysis showed mean quality-adjusted life-years of 1.103 ± 0.69 for PCI first, 1.088±0.70 for medical management, and 0.670±0.58 for HD followed by PCI. Probabilistic sensitivity analysis found PCI as the preferred strategy > 60% of the time.

LIMITATIONS

Values for probabilities and utilities were estimated and/or derived from multiple sources that were not uniform in their populations in terms of age, comorbid condition burden, and degree of kidney failure, and several simplifying assumptions were made.

CONCLUSIONS

Our analysis demonstrates that quality-adjusted life expectancy is similar for the PCI first and medical management strategies in patients with advanced CKD with stable angina and that the decision depends on patient preferences other than those incorporated in our model. Both strategies are superior to preemptive dialysis.

Characteristics of Coronary Artery to Pulmonary Artery Fistula on Coronary Computed Tomography Angiography

OBJECTIVE

The aim of the study was to evaluate the characteristics of coronary artery-to-pulmonary artery fistula (CPAF) found by coronary computed tomography (CT) angiography.

METHODS

Among 10,121 cases of coronary CT angiography performed for 7 years, we found 32 cases of CPAF. We retrospectively evaluated the demographics, clinical symptoms, and anatomical characteristics such as the origin, number of origins, course, opening site of the fistula, and the presence of aneurysmal changes (defined as dilatation 1.5 times the diameter of the origin). We also categorized the fistula openings according to size compared with that of the proximal left anterior descending coronary artery.

RESULTS

The patients were 14 men and 18 women with a mean (range) age of 56.5 (34-86) years. Nineteen patients had no related symptoms, and the other 13 patients had symptoms such as angina, chest discomfort, palpitations, or shoulder pain. Among these patients, 2 patients were diagnosed with coronary artery disease. The origins of CPAF were single (n = 15, 46.9%) or multiple (n = 17, 53.1%). The CPAFs arose most commonly from the conus branch of the right coronary artery (n = 20, 62.5%) and proximal left anterior descending (n = 17, 53.1%). All CPAFs coursed anteriorly to the main pulmonary artery and drained into the anterolateral aspect. Twenty-five patients (78.1%) exhibited aneurysmal changes. The openings were small in 13 (40.6%), medium in 13 (40.6%), and large in 6 (18.8%) patients.

CONCLUSIONS

More than half of patients with CPAF had no related symptoms. Coronary artery-to-pulmonary artery fistula may have a single origin or multiple origins. All of the CPAFs coursed anteriorly to the main pulmonary artery and drained into the anterolateral aspect; the CPAFs identified here frequently exhibited aneurysmal changes.

Changes in Medical Therapy and Lifestyle After Anatomical or Functional Testing for Coronary Artery Disease

Background

Diagnostic testing in the care of patients newly presenting with symptoms suggestive of coronary artery disease may influence risk factor management, independent of test type or test results. However, little is known about changes in medications and lifestyle after anatomical or functional testing.

Methods and Results

We examined what factors influenced preventive medical therapy and lifestyle practices at 60 days among 10 003 symptomatic patients (53% women; mean age 61 years) randomly assigned to anatomical testing with coronary computed tomographic angiography or functional testing (NCT01174550). We also assessed the association of preventive changes with major cardiovascular events. There were no differences in medications/lifestyle at baseline. At 60 days, relative to baseline, the computed tomographic angiography strategy was associated with a higher proportion of patients newly initiating aspirin (11.8% versus 7.8%), statins (12.7% versus 6.2%), and β‐blockers (8.1% versus 5.3%), compared to functional testing (P<0.0001 for each). No significant differences between computed tomographic angiography and functional testing strategies were observed for initiation of exercise, quitting smoking, or weight loss in overweight/obese patients, though overall prevalence of healthy eating was higher after computed tomographic angiography (P=0.002) while obese/overweight status was lower (P=0.040). Positive initial test results and revascularization demonstrated stronger associations with preventive medications and lifestyle than test type. Medication initiation was not associated with fewer cardiovascular events.

Conclusions

Positive initial test results and revascularization are primary drivers of changes in preventive medical and lifestyle practices, with test type making secondary contributions. However, substantial opportunities exist to further reduce cardiovascular risk.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01174550.

Calcium Scoring and Cardiac Computed Tomography

Although recent advances in noninvasive imaging technologies have potentially improved diagnostic efficiency and clinical outcomes of patients with acute chest pain, controversy remains regarding much of the accumulated evidence. This article reviews the role of coronary computed tomography (CT) angiography in the assessment of coronary risk, and its usefulness in the emergency department in facilitating appropriate disposition decisions. Also discussed is coronary artery calcification incidentally found on CT scans when done for indications such as evaluation of pulmonary embolism or lung cancer. The evidence base and clinical applications for both techniques are described, together with cost-effectiveness and radiation exposure considerations.

Cardiac computed tomography for the evaluation of the acute chest pain syndrome: state of the art

Coronary computed tomography angiography (CCTA) is recommended for the triage of acute chest pain in patients with a low-to-intermediate likelihood for acute coronary syndrome. Absence of coronary artery disease (CAD) confirmed by CCTA allows rapid emergency department discharge. This article shows that CCTA-based triage is as safe as traditional triage, reduces the hospital length of stay, and may provide cost-effective or even cost-saving care.

Physician decision making and trends in the use of cardiac stress testing in the United States: an analysis of repeated cross-sectional data

BACKGROUND

Cardiac stress testing, particularly with imaging, has been the focus of debates about rising health care costs, inappropriate use, and patient safety in the context of radiation exposure.

OBJECTIVE

To determine whether U.S. trends in cardiac stress test use may be attributable to population shifts in demographics, risk factors, and provider characteristics and evaluate whether racial/ethnic disparities exist in physician decision making.

DESIGN

Analyses of repeated cross-sectional data.

SETTING

National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey (1993 to 2010).

PATIENTS

Adults without coronary heart disease.

MEASUREMENTS

Cardiac stress test referrals and inappropriate use.

RESULTS

Between 1993 to 1995 and 2008 to 2010, the annual number of U.S. ambulatory visits in which a cardiac stress test was ordered or performed increased from 28 per 10,000 visits to 45 per 10,000 visits. No trend was found toward more frequent testing after adjustment for patient characteristics, risk factors, and provider characteristics (P = 0.134). Cardiac stress tests with imaging comprised a growing portion of all tests, increasing from 59% in 1993 to 1995 to 87% in 2008 to 2010. At least 34.6% were probably inappropriate, with associated annual costs and harms of $501 million and 491 future cases of cancer. Authors found no evidence of a lower likelihood of black patients receiving a cardiac stress test (odds ratio, 0.91 [95% CI, 0.69 to 1.21]) than white patients, although some evidence of disparity in Hispanic patients was found (odds ratio, 0.75 [CI, 0.55 to 1.02]).

LIMITATION

Cross-sectional design with limited clinical data.

CONCLUSION

National growth in cardiac stress test use can largely be explained by population and provider characteristics, but use of imaging cannot. Physician decision making about cardiac stress test use does not seem to contribute to racial/ethnic disparities in cardiovascular disease.

PRIMARY FUNDING SOURCE

National Heart, Lung, and Blood Institute and the National Center for Advancing Translational Sciences.

Coronary computed tomographic angiography in the emergency room: state of the art

Chest pain is a common complaint in the emergency department often necessitating testing to exclude underlying obstructive coronary artery disease. While the traditional evaluation of patients with suspected acute coronary syndrome often consists of serial electrocardiograms and cardiac biomarkers, followed by selective use of stress testing for further risk stratification, this approach is costly and inefficient. Recently, coronary computed tomographic angiography (CTA) has offered an alternative approach with a high sensitivity and negative predictive value to exclude obstructive coronary artery disease that can rapidly identify patients with low rates of downstream major adverse cardiac events. In this review, the authors provide an overview of available data on the use of CTA for evaluating acute chest pain, while emphasizing its advantages and disadvantages compared to existing strategies. In addition, we provide a suggested algorithm to identify how CTA can be incorporated into the evaluation of acute chest pain and discuss tips for successful implementation of CTA in the emergency department.

Cost-effectiveness of a novel blood-pool contrast agent in the setting of chest pain evaluation in an emergency department

OBJECTIVE

We evaluated three diagnostic strategies with the objective of comparing the current standard of care for individuals presenting acute chest pain and no history of coronary artery disease (CAD) with a novel diagnostic strategy using an emerging technology (blood-pool contrast agent [BPCA]) to identify the potential benefits and cost reductions.

MATERIALS AND METHODS

A decision analytic model of diagnostic strategies and outcomes using a BPCA and a conventional agent for CT angiography (CTA) in patients with acute chest pain was built. The model was used to evaluate three diagnostic strategies: CTA using a BPCA followed by invasive coronary angiography (ICA), CTA using a conventional agent followed by ICA, and ICA alone.

RESULTS

The use of the two CTA-based triage tests before ICA in a population with a CAD prevalence of less than 47% was predicted to be more cost-effective than ICA alone. Using the base-case values and a cost premium for BPCA over the conventional CT agent (cost of BPCA ≈ 5× that of a conventional agent) showed that CTA with a BPCA before ICA resulted in the most cost-effective strategy; the other strategies were ruled out by simple dominance. The model strongly depends on the rates of complications from the diagnostic tests included in the model. In a population with an elevated risk of contrast-induced nephropathy (CIN), a significant premium cost per BPCA dose still resulted in the alternative whereby CTA using BPCA was more cost-effective than CTA using a conventional agent. A similar effect was observed for potential complications resulting from the BPCA injection. Conversely, in the presence of a similar complication rate from BPCA, the diagnostic strategy of CTA using a conventional agent would be the optimal alternative.

CONCLUSION

BPCAs could have a significant impact in the diagnosis of acute chest pain, in particular for populations with high incidences of CIN. In addition, a BPCA strategy could garner further savings if currently excluded phenomena including renal disease and incidental findings were included in the decision model.

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

BACKGROUND

Coronary computed tomographic angiography (cCTA) allows rapid, noninvasive exclusion of obstructive coronary artery disease (CAD). However, concern exists whether implementation of cCTA in the assessment of patients presenting to the emergency department with acute chest pain will lead to increased downstream testing and costs compared with alternative strategies. Our aim was to compare observed actual costs of usual care (UC) with projected costs of a strategy including early cCTA in the evaluation of patients with acute chest pain in the Rule Out Myocardial Infarction Using Computer Assisted Tomography I (ROMICAT I) study.

METHODS AND RESULTS

We compared cost and hospital length of stay of UC observed among 368 patients enrolled in the ROMICAT I study with projected costs of management based on cCTA. Costs of UC were determined by an electronic cost accounting system. Notably, UC was not influenced by cCTA results because patients and caregivers were blinded to the cCTA results. Costs after early implementation of cCTA were estimated assuming changes in management based on cCTA findings of the presence and severity of CAD. Sensitivity analysis was used to test the influence of key variables on both outcomes and costs. We determined that in comparison with UC, cCTA-guided triage, whereby patients with no CAD are discharged, could reduce total hospital costs by 23% (P<0.001). However, when the prevalence of obstructive CAD increases, index hospitalization cost increases such that when the prevalence of ≥ 50% stenosis is >28% to 33%, the use of cCTA becomes more costly than UC.

CONCLUSIONS

cCTA may be a cost-saving tool in acute chest pain populations that have a prevalence of potentially obstructive CAD <30%. However, increased cost would be anticipated in populations with higher prevalence of disease.

Triage of patients presenting with chest pain to the emergency department: implementation of coronary CT angiography in a large urban health care system

OBJECTIVE

There is growing evidence supporting the use of coronary CT angiography (CTA) to triage patients in the emergency department (ED) with acute chest pain and low risk of acute coronary syndrome (ACS). We hypothesized that coronary CTA can guide early management and safely discharge patients by introducing a dedicated patient management protocol.

SUBJECTS AND METHODS

We conducted a prospective cohort study in three EDs of a large health care system (> 1300 beds). Five hundred twenty-nine patients (mean age, 52.1 years; 56% women) with chest pain, negative cardiac enzyme results, normal or nondiagnostic ECG findings, and a thrombolysis in myocardial infarction (TIMI) risk score of 2 or less were admitted and underwent CTA. A new dedicated chest pain triage protocol (levels 1-5) was implemented. On the basis of CTA findings, patients were stratified into one of the following four groups: 0, low (negative CTA findings); 1, mild (1-49% stenosis); 2, moderate (50-69% stenosis); or 3, severe (≥ 70% stenosis) risk of ACS. Outcome measures included major adverse cardiac events (MACEs) during the first 30 days after CTA, downstream testing results, and length of stay (LOS). LOS was compared before and after implementation of our chest pain triage protocol.

RESULTS

Three hundred seventeen patients (59.9%) with negative CTA findings and 151 (28.5%) with mild stenosis were discharged from the ED with a very low downstream testing rate and a very low MACE rate (negative predictive value = 99.8%). Twenty-five patients (4.7%) had moderate stenosis (n = 17 undergoing further testing). Thirty-six patients (6.8%) had stenosis of 70% or greater by CTA (n = 34 positive by invasive angiography or SPECT-myocardial perfusion imaging). The sensitivity of CTA was 94%. The rate of MACEs in patients with stenosis of 70% or greater (8.3%) was significantly higher (p < 0.001) than in patients with negative CTA findings (0%) or those with mild stenosis (0.2%). A 51% decrease in LOS-from 28.8 to 14.0 hours--was noted after implementation of the dedicated chest pain protocol (p < 0.001).

CONCLUSION

Chest pain patients with negative or mild nonobstructive CTA findings can be safely discharged from the ED without further testing. Implementation of a dedicated chest pain triage protocol is critical for the success of a coronary CTA program.

Role of multidetector computed tomography in the diagnosis and management of patients attending the rapid access chest pain clinic, The Scottish computed tomography of the heart (SCOT-HEART) trial: study protocol for randomized controlled trial

Background

Rapid access chest pain clinics have facilitated the early diagnosis and treatment of patients with coronary heart disease and angina. Despite this important service provision, coronary heart disease continues to be under-diagnosed and many patients are left untreated and at risk. Recent advances in imaging technology have now led to the widespread use of noninvasive computed tomography, which can be used to measure coronary artery calcium scores and perform coronary angiography in one examination. However, this technology has not been robustly evaluated in its application to the clinic.

Methods/design

The SCOT-HEART study is an open parallel group prospective multicentre randomized controlled trial of 4,138 patients attending the rapid access chest pain clinic for evaluation of suspected cardiac chest pain. Following clinical consultation, participants will be approached and randomized 1:1 to receive standard care or standard care plus ≥64-multidetector computed tomography coronary angiography and coronary calcium score. Randomization will be conducted using a web-based system to ensure allocation concealment and will incorporate minimization. The primary endpoint of the study will be the proportion of patients diagnosed with angina pectoris secondary to coronary heart disease at 6 weeks. Secondary endpoints will include the assessment of subsequent symptoms, diagnosis, investigation and treatment. In addition, long-term health outcomes, safety endpoints, such as radiation dose, and health economic endpoints will be assessed. Assuming a clinic rate of 27.0% for the diagnosis of angina pectoris due to coronary heart disease, we will need to recruit 2,069 patients per group to detect an absolute increase of 4.0% in the rate of diagnosis at 80% power and a two-sided P value of 0.05. The SCOT-HEART study is currently recruiting participants and expects to report in 2014.

Discussion

This is the first study to look at the implementation of computed tomography in the patient care pathway that is outcome focused. This study will have major implications for the management of patients with cardiovascular disease.

Trial registration

ClinicalTrials.gov Identifier: NCT01149590

Exposure to ionizing radiation and estimate of secondary cancers in the era of high-speed CT scanning: projections from the Medicare population

PURPOSE

The aims of this study were to analyze the distribution and amount of ionizing radiation delivered by CT scans in the modern era of high-speed CT and to estimate cancer risk in the elderly, the patient group most frequently imaged using CT scanning.

METHODS

A retrospective cohort study was conducted using Medicare claims spanning 8 years (1998-2005) to assess CT use. The data were analyzed in two 4-year cohorts, 1998 to 2001 (n = 5,267,230) and 2002 to 2005 (n = 5,555,345). The number and types of CT scans each patient received over the 4-year periods were analyzed to determine the percentage of patients exposed to threshold radiation of 50 to 100 mSv (defined as low) and >100 mSv (defined as high). The National Research Council's Biological Effects of Ionizing Radiation VII models were used to estimate the number of radiation-induced cancers.

RESULTS

CT scans of the head were the most common examinations in both Medicare cohorts, but abdominal imaging delivered the greatest proportion (43% in the first cohort and 40% in the second cohort) of radiation. In the 1998 to 2001 cohort, 42% of Medicare patients underwent CT scans, with 2.2% and 0.5% receiving radiation doses in the low and high ranges, respectively. In the 2002 to 2005 cohort, 50% of Medicare patients received CT scans, with 4.2% and 1.2% receiving doses in the low and high ranges. In the two populations, 1,659 (0.03%) and 2,185 (0.04%) cancers related to ionizing radiation were estimated, respectively.

CONCLUSIONS

Although radiation doses have been increasing along with the increasing reliance on CT scans for diagnosis and therapy, using conservative estimates with worst-case scenario methodology, the authors found that the risk for secondary cancers is low in older adults, the group subjected to the most frequent CT scanning. Trends showing increasing use, however, underscore the importance of monitoring CT utilization and its consequences.

Incremental prognostic value of different components of coronary atherosclerotic plaque at cardiac CT angiography beyond coronary calcification in patients with acute chest pain

PURPOSE

To systematically evaluate the incremental predictive value of cardiac computed tomographic (CT) angiography beyond the assessment of coronary artery calcium (CAC) in patients who present with acute chest pain but without evidence of acute coronary syndrome (ACS).

MATERIALS AND METHODS

The human research committee approved this study and waived the need for individual written informed consent. The study was HIPAA compliant. A total of 458 patients (36% male; mean age, 55 years ± 11) with acute chest pain at low to intermediate risk for coronary artery disease underwent coronary calcification assessment with cardiac CT angiography. All patients who did not experience ACS at index hospitalization were followed for instances of a major adverse cardiac event (MACE), such as a myocardial infarct, revascularization, cardiac death, or angina requiring hospitalization. CAC score and cardiac CT angiography were used to derive the presence and extent of atherosclerotic plaque (calcified, noncalcified, or mixed), and obstructive lesions (>50% luminal narrowing) were related to outcomes by using univariate and adjusted Cox proportional hazards models.

RESULTS

Of the 458 patients, 70 (15%) experienced MACE (median follow-up, 13 months). Patients with no plaque at cardiac CT angiography remained free of events during the follow-up period, while 11 (5%) of 215 patients with no CAC had MACE. The extent of plaque was the strongest predictor of MACE independent of traditional risk factors (hazard ratio [HR], 151.77 for four or more segments containing plaque as compared with those containing no plaque; P < .001). Patients with mixed plaque were more likely to experience MACE (HR, 86.96; P = .002) than those with exclusively noncalcified plaque (HR, 58.06; P = .005) or exclusively calcified plaque (HR, 32.94; P = .02).

CONCLUSION

The strong prognostic value of cardiac CT angiography is incremental to its known diagnostic value in patients with acute chest pain without ACS and is independent of traditional risk factors and CAC.

Coronary CT and the coronary calcium score, the future of ED risk stratification?

Accurate and efficient evaluation of acute chest pain remains clinically challenging because traditional diagnostic modalities have many limitations. Recent improvement in non-invasive imaging technologies could potentially improve both diagnostic efficiency and clinical outcomes of patients with acute chest pain while reducing unnecessary hospitalizations. However, there is still controversy regarding much of the evidence for these technologies. This article reviews the role of coronary artery calcium score and the coronary computed tomography in the assessment of individual coronary risk and their usefulness in the emergency department in facilitating appropriate disposition decisions. The evidence base and clinical applications for both techniques are also described, together with cost- effectiveness and radiation exposure considerations.

Accuracy, risk and the intrinsic value of diagnostic imaging: a review of the cost-utility literature

RATIONALE AND OBJECTIVES

The aim of this study was to systematically review the reporting of the value of imaging unrelated to treatment consequences and test characteristics in all imaging-related published cost-utility analyses (CUAs) in the medical literature.

MATERIALS AND METHODS

All CUAs published between 1976 and 2008 evaluating diagnostic imaging technologies contained in the CEA Registry, a publicly available comprehensive database of health related CUAs, were screened. Publication characteristics, imaging modality, and the inclusion of test characteristics including accuracy, costs, risks, and the potential value unrelated to treatment consequences (eg, reassurance or anxiety) were assessed.

RESULTS

Ninety-six published CUAs evaluating 155 different imaging technologies were included in the final sample; 27 studies were published in imaging-specialized journals. Fifty-two studies (54%) evaluated the performance of a single imaging modality, while 44 studies (46%) compared two or more different imaging modalities. The most common areas of interest were cardiovascular (45%) and neuroradiology (17%). Forty-two technologies (27%) concerned ultrasound, while 34 (22%) concerned magnetic resonance. Seventy-nine (51%) technologies used ionizing radiation. Test accuracy was reported or calculated for 90% (n = 133 and n = 5, respectively) and assumed perfect (reference test or gold-standard test without alternative testing strategy to capture false-negatives and false-positives) for 8% (n = 12) of technologies. Only 22 studies (23%) assessing 40 imaging technologies (26%) considered inconclusive or indeterminate results. The risk of testing was reported for 32 imaging technologies (21%). Fifteen studies (16%) considered the value of diagnostic imaging unrelated to treatment. Four studies incorporated it as quality-of-life adjustments, while 10 studies mentioned it only in their discussions or as a limitation.

CONCLUSIONS

The intrinsic value of imaging (the value of imaging unrelated to treatment) has not been appropriately defined or incorporated in the existing cost-utility literature, which could be due to a lack of evidence on the issue. Thus, more research is needed on metrics for a more comprehensive evaluation of diagnostic imaging. Similarly, the incorporation of variations in imaging tests accuracy, inconclusive results and associated risks has lacked uniformity in the cost-utility literature. Acknowledgment of these characteristics in future cost-utility publications will enhance their value and provide results that more closely resemble routine clinical practice.

Clinical indications for cardiac computed tomography. From the Working Group of the Cardiac Radiology Section of the Italian Society of Medical Radiology (SIRM)

Cardiac computed tomography (CCT) has grown as a useful means in different clinical contexts. Technological development has progressively extended the indications for CCT while reducing the required radiation dose. Even today there is little documentation from the main international scientific societies describing the proper use and clinical indications of CCT; in particular, there are no complete guidelines. This document reflects the position of the Working Group of the Cardiac Radiology Section of the Italian Society of Radiology concerning the indications for CCT.

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.

Cardiac CT in women: clinical application and considerations

Cardiac computed tomography (CT) has special considerations and applications in women for the evaluation of coronary heart disease (CHD). Unique aspects of cardiovascular disease (CVD) in women include atypical symptoms and a later presentation of CHD. Disparities exist in mortality trends of CVD between men and women along with a lack of patient awareness of CVD as a significant cause of mortality for women. Differences have also become evident among plaque characteristics between the 2 sexes, with a relative increased prevalence of noncalcified plaque in women. Traditional risk prediction models, such as the Framingham Risk Score (FRS), have limitations in this population. Coronary calcium scanning contributes significantly to the accuracy of CHD detection on top of traditional CV risk factors in asymptomatic women. Coronary CT angiography has proven accurate for the diagnosis of significant CHD as well as cost effective in the evaluation of symptomatic women. The safety issue of radiation exposure with cardiac CT warrants special consideration for women. Concern for radiation-related cancer risks and organ-specific dose delivered to the breast is being addressed by radiation-reducing techniques. Future technologic advances in CT may allow for simultaneous screening for CHD and other disease processes, such as osteoporosis, breast cancer, and visceral adiposity in one routine test.

Coronary CT angiography: current status and continuing challenges

Coronary CT angiography has been increasingly used in the diagnosis of coronary artery disease owing to rapid technological developments, which are reflected in the improved spatial and temporal resolution of the images. High diagnostic accuracy has been achieved with multislice CT scanners (64 slice and higher), and in selected patients coronary CT angiography is regarded as a reliable alternative to invasive coronary angiography. With high-quality coronary CT imaging increasingly being performed, patients can benefit from an imaging modality that provides a rapid and accurate diagnosis while avoiding an invasive procedure. Despite the tremendous contributions of coronary CT angiography to cardiac imaging, study results reported in the literature should be interpreted with caution as there are some limitations existing within the study design or related to patient risk factors. In addition, some attention must be given to the potential health risks associated with the ionising radiation received during cardiac CT examinations. Radiation dose associated with coronary CT angiography has raised serious concerns in the literature, as the risk of developing malignancy is not negligible. Various dose-saving strategies have been implemented, with some of the strategies resulting in significant dose reduction. The aim of this review is to present an overview of the role of coronary CT angiography on cardiac imaging, with focus on coronary artery disease in terms of the diagnostic and prognostic value of coronary CT angiography. Various approaches for dose reduction commonly recommended in the literature are discussed. Limitations of coronary CT angiography are identified. Finally, future directions and challenges with the use of coronary CT angiography are highlighted.

[Triple rule-out computed tomography in emergency departments]

In the emergency department patients with chest pain play an important role because the underlying and concealed diseases can be life-threatening. The complaints are often nonspecific and patients also have different risk profiles. In patients in the emergency department with nonspecific chest pain a"1-stop strategy" for elucidation of the three main organs lung, hear and aorta with the 4 main differential diagnoses (aortic dissection, ruptured aortic aneurysm, pulmonary embolism and coronary heart disease) is desirable. Technical advances in computed tomography (CT) in recent years make this approach technically possible. In modern emergency departments CT equipment is becoming more and more common in order to rapidly examine trauma patients. A meaningful patient selection and preparation are, however, necessary to avoid unnecessary exposure of patients to contrast media and radiation. In this way it is possible to reduce the rate of overlooked diseases or false diagnoses.

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

OBJECTIVES

To determine the incremental benefit of assessing myocardial perfusion defects (MPD) for acute coronary syndromes (ACS) over coronary and functional assessment by rest cardiac computed tomography (CT) in patients with acute chest pain.

BACKGROUND

Assessment of myocardial perfusion is feasible with cardiac CT; however, the diagnostic value of this assessment in patients at risk for ACS has not been demonstrated.

METHODS

The study included patients who presented to the emergency department with acute chest pain, nonischemic initial electrocardiogram (ECG), and negative cardiac biomarkers but had clinical suspicion for ACS and underwent invasive coronary angiography (ICA). Results were blinded to caregivers and patients. CT data sets were independently assessed for the presence of coronary plaque and stenosis, regional left ventricular function, and myocardial perfusion deficits by 2 blinded observers. Coronary angiography was assessed for the presence of stenosis, TIMI myocardial perfusion grade, and corrected TIMI frame count. The endpoint was ACS during index hospitalization.

RESULTS

We analyzed data from 35 subjects (69% male, mean age 58 ± 9 years) of whom 22 (63%) had ACS. The sensitivity and specificity of MPD for ACS were 86% (95% CI: 64%-96%) and 62% (95% CI: 32%-85%), respectively. Combined, MPD and RWMA assessment resulted in specificity and sensitivity of 86% (95% CI: 64%-96%) and 85% (95% CI: 54%-97%), respectively. Adding MPD and RWMA to the assessment for significant stenosis (>50%) resulted in a higher sensitivity of 91% (69-98%) and specificity of 85% (54-97%) and a significantly increased overall diagnostic accuracy when compared with assessment for stenosis (AUC: 0.88 vs 0.79; respectively, P = 0.02). Diagnostic accuracy of CT was not associated with impaired CTFC >40 or myocardial TIMI perfusion grade < 3.

CONCLUSIONS

Assessment of myocardial perfusion and regional wall motion abnormalities may enhance the ability of CT to detect ACS in patients with acute chest pain.

Non-obstructive coronary artery disease upon multi-detector computed tomography in patients presenting with acute chest pain--results of an intermediate term follow-up

AIMS

Multi-detector computed tomography (MDCT) has emerged as an efficient tool for detection of obstructive coronary artery disease (CAD) and assessment of patients with acute chest pain. MDCT may detect premature, non-obstructive atherosclerotic lesions which otherwise would have not been detected upon functional cardiac imaging tests. Currently, there is scarce data regarding the clinical significance of these lesions. The purpose of this study was to prospectively analyse the intermediate term outcome of patients admitted to chest pain unit (CPU) with findings of non-obstructive CAD upon MDCT. Method and results The study comprised 444 patients admitted to the CPU at Sheba Medical Center and underwent evaluation by MDCT for complaints of acute chest pain. Studies were classified as: normal; non-obstructive CAD (defined as any narrowing <50% diameter stenosis); obstructive CAD (narrowing of ≥ 50% diameter stenosis); or non-diagnostic. Patients were followed up for a minimum of 1 year and outcomes were compared between the non-obstructive (n = 115) and the normal (n = 266) MDCT groups in regard to MACE [coronary revascularization, acute coronary syndrome (ACS), and death]. Comparing the groups, those with non-obstructive CAD were older, more likely to be males, and dyslipidaemic. During an intermediate term follow-up (2.5 ± 0.4 years) MACE was equally low between the two groups (1% for both groups; P = 0.9).

CONCLUSION

Among patients evaluated by MDCT for acute chest pain, during an intermediate term follow-up, those with non-obstructive CAD had a benign clinical outcome compared with those with normal coronary arteries.

Cost-effectiveness of coronary computed tomography and cardiac stress imaging in the emergency department: a decision analytic model comparing diagnostic strategies for chest pain in patients at low risk of acute coronary syndromes

Emergency department presentations with chest pain are expensive and often unrelated to coronary artery disease (CAD). Coronary computed tomographic angiography (CTA) may allow earlier discharge of low-risk patients, resulting in cost savings. We modeled clinical and economic outcomes of diagnostic strategies in patients with chest pain and at low risk of CAD: exercise electrocardiography (ECG), stress single-photon emission computed tomography (SPECT), stress echocardiography, and a CTA strategy comprising an initial CTA scan with confirmatory SPECT for indeterminate results. Our results suggest that a 2-step diagnostic strategy of CTA with SPECT for intermediate scans is likely to be less costly and more effective for the diagnosis of a patient group at low risk of CAD and a prevalence of 2% to 30%. The CTA strategies were cost saving (lower costs, higher quality-adjusted life-years) compared with stress ECG, echocardiography, and SPECT. Confirming intermediate/indeterminate CTA scans with SPECT results in cost savings and quality-adjusted life-year gains due to reduced hospitalization of patients who returned false-positive initial CTA test. However, CTA may be associated with a higher event rate in negative patients than SPECT, and the diagnostic and prognostic information for the use of CTA in the emergency department is evolving. Large comparative, randomized, controlled trials of the different diagnostic strategies are needed to compare the long-term costs and consequences of each strategy in a population of defined low-risk patients in the emergency department.

Cost-effectiveness analysis and HIV screening: the emergency medicine perspective

Cost-effectiveness analysis is a useful tool for decisionmakers charged with prioritizing of the myriad medical interventions in the emergency department (ED). This analytic approach may be especially helpful for ranking programs that are competing for scarce resources while attempting to maximize net health benefits. In this article, we review the health economics literature on HIV screening in EDs and introduce the methods of cost-effectiveness analysis for medical interventions. We specifically describe the incremental cost-effectiveness ratio--its calculation, the derivation of ratio components, and the interpretation of these ratios.

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

OBJECTIVES

The aim of this study was to determine the 2-year prognostic value of cardiac computed tomography (CT) for predicting major adverse cardiac events (MACE) in patients presenting to the emergency department (ED) with acute chest pain.

BACKGROUND

CT has high potential for early triage of acute chest pain patients. However, there is a paucity of data regarding the prognostic value of CT in this ED cohort.

METHODS

We followed 368 patients from the ROMICAT (Rule Out Myocardial Infarction Using Computer Assisted Tomography) trial (age 53 ± 12 years; 61% male) who presented to the ED with acute chest pain, negative initial troponin, and a nonischemic electrocardiogram for 2 years. Contrast-enhanced 64-slice CT was obtained during index hospitalization, and caregivers and patients remained blinded to the results. CT was assessed for the presence of plaque, stenosis (>50% luminal narrowing), and left ventricular regional wall motion abnormalities (RWMA). The primary endpoint was MACE, defined as composite cardiac death, nonfatal myocardial infarction, or coronary revascularization.

RESULTS

Follow-up was completed in 333 patients (90.5%) with a median follow-up period of 23 months. At the end of the follow-up period, 25 patients (6.8%) experienced 35 MACE (no cardiac deaths, 12 myocardial infarctions, and 23 revascularizations). Cumulative probability of 2-year MACE increased across CT strata for coronary artery disease (CAD) (no CAD 0%; nonobstructive CAD 4.6%; obstructive CAD 30.3%; log-rank p < 0.0001) and across combined CT strata for CAD and RWMA (no stenosis or RWMA 0.9%; 1 feature-either RWMA [15.0%] or stenosis [10.1%], both stenosis and RWMA 62.4%; log-rank p < 0.0001). The c statistic for predicting MACE was 0.61 for clinical Thrombolysis In Myocardial Infarction risk score and improved to 0.84 by adding CT CAD data and improved further to 0.91 by adding RWMA (both p < 0.0001).

CONCLUSIONS

CT coronary and functional features predict MACE and have incremental prognostic value beyond clinical risk score in ED patients with acute chest pain. The absence of CAD on CT provides a 2-year MACE-free warranty period, whereas coronary stenosis with RWMA is associated with the highest risk of MACE.

Diagnosis of coronary stenosis with CT angiography comparison of automated computer diagnosis with expert readings

RATIONALE AND OBJECTIVES

To compare computer-generated interpretation of coronary computed tomography angiography (cCTA) by commercially available COR Analyzer software with expert human interpretation.

MATERIALS AND METHODS

This retrospective Health Insurance Portability and Accountability Act‑compliant study was approved by the institutional review board. Among 225 consecutive cCTA examinations, 207 were of adequate quality for automated evaluation. COR Analyzer interpretation was compared to human expert interpretation for detection of stenosis defined as ≥50% vessel diameter reduction in the left main, left anterior descending (LAD), circumflex (LCX), right coronary artery (RCA), or a branch vessel (diagonal, ramus, obtuse marginal, or posterior descending artery).

RESULTS

Among 207 cases evaluated by COR Analyzer, human expert interpretation identified 48 patients with stenosis. COR Analyzer identified 44/48 patients (sensitivity 92%) with a specificity of 70%, a negative predictive value of 97% and a positive predictive value of 48%. COR Analyzer agreed with the expert interpretation in 75% of patients. With respect to individual segments, COR Analyzer detected 9/10 left main lesions, 33/34 LAD lesions, 14/15 LCX lesions, 27/31 RCA lesions, and 8/11 branch lesions. False-positive interpretations were localized to the left main (n = 16), LAD (n = 26), LCX (n = 21), RCA (n = 21), and branch vessels (n = 23), and were related predominantly to calcified vessels, blurred vessels, misidentification of vessels and myocardial bridges.

CONCLUSIONS

Automated computer interpretation of cCTA with COR Analyzer provides high negative predictive value for the diagnosis of coronary disease in major coronary arteries as well as first-order arterial branches. False-positive automated interpretations are related to anatomic and image quality considerations.