Acute chest pain investigation: utility of cardiac CT angiography in guiding troponin measurement

Evaluation of the Practice Guideline Used for Rule-Out of Myocardial Infarction at a Tertiary Cardiology Center

INTRODUCTION

With the current high burden on the healthcare system and limited resources, the efficient utilization of facilities is of utmost importance. We sought to present the practice guideline used at a high prevalence tertiary cardiology center and compare its safety and efficacy performance with the single high-sensitivity cardiac troponin T strategy, conventional and modified HEART score.

METHODS

In this prospective cohort study, consecutive patients presenting to the emergency department with chest pain or an angina equivalent were recruited. The primary endpoints consisted of major adverse cardiac events at index visits and 30-day follow-up. Patients were managed according to the practice guideline, and sensitivity and negative predictive values were compared.

RESULTS

Of the total 1548 patients, the mean age was 50.4 ± 15.7 years. Ninety-nine (10.9%) patients were admitted at the index visit, and 89 patients were consequently diagnosed with acute coronary symptoms. Six (0.007%) patients experienced major adverse cardiac events within the 30-day follow-up among discharged patients. Among 911 patients with at least 1 troponin, using single high-sensitivity cardiac troponin T, HEART score, and modified HEART score would have further admitted 805, 450, and 609 patients, respectively. The negative predictive value for all 4 algorithms did not significantly differ (99.2% vs. 100% vs. 99.3% vs. 99.6%, respectively).

CONCLUSIONS

The Tehran Herat Center protocol was a relatively safe protocol with high efficacy. Despite the high safety of the other diagnostic pathways, the high volume of patients needing additional evaluation could impose a high burden on the health care system.

Risk Factors Predisposing to Angina in Patients with Non-Obstructive Coronary Arteries: A Retrospective Analysis

No hemodynamically significant atherosclerotic plaques are observed in up to 30% of patients reporting angina and undergoing coronary angiography. To investigate risk factors associated with non-obstructive coronary artery disease (NOCAD), we analyzed the medical records of, consecutively, 136 NOCAD subjects and 128 patients with significant stenosis in at least one coronary artery (the OCAD group). The blood concentrations of the TC (4.40 [3.78−5.63] mmol/L vs. 4.12 [3.42−5.01] mmol/L; p = 0.026), LDL-C (2.32 [1.80−3.50] mmol/L vs. 2.10 [1.50−2.70] mmol/L; p = 0.003), non-HDL-C (2.89 [2.29−4.19] mmol/L vs. 2.66 [2.06−3.39] mmol/L; p = 0.045), as well as the LDL-C/HDL-C ratio (1.75 [1.22−2.60] vs. 1.50 [1.10−1.95]; p = 0.018) were significantly increased in the NOCAD patients compared to the OCAD group due to the lower prevalence and intensity of the statin therapy in the NOCAD individuals (p < 0.001). Moreover, the abovementioned lipid parameters appeared to be valuable predictors of NOCAD, with the LDL-C (OR = 1.44; 95%CI = 1.14−1.82) and LDL-C/HDL-C (OR = 1.51; 95%CI = 1.13−2.02) showing the highest odds ratios. Furthermore, multivariable logistic regression models determined female sex as the independent risk factor for NOCAD (OR = 2.37; 95%CI = 1.33−4.20). Simultaneously, arterial hypertension substantially lowered the probability of NOCAD (OR = 0.21; 95%CI = 0.10−0.43). To conclude, female sex, the absence of arterial hypertension, as well as increased TC, LDL-C, non-HDL, and LDL-C/HDL-C ratio are risk factors for NOCAD in patients reporting angina, potentially as a result of poor hypercholesterolemia management.

Major adverse cardiac events after emergency department evaluation of chest pain patients with advanced testing: Systematic review and meta-analysis

OBJECTIVES

Our primary objective was to describe the risk of major adverse cardiac events (MACE) at 1, 6, and 12 months after a negative coronary computed tomography angiogram (cCTA), electrocardiogram (ECG) stress test, stress echocardiography, and myocardial perfusion scintigraphy (MPS) in low- to intermediate-risk patients.

METHODS

Initially, 952 articles were identified for screening, 81 met criteria for full-text review, and once risk of bias was assessed, 33 articles were included in this meta-analysis. We utilized a random-effects model to assess pooled MACE event proportion for patients undergoing evaluation of acute coronary syndrome (ACS) when risk stratified to a low- to intermediate-risk category after undergoing standard testing. Heterogeneity analysis was performed using Cochrane's Q-test and I² statistic.

RESULTS

Twenty-one studies evaluated follow-up at 1 month with cCTA having a 0.09% (95% confidence interval [CI] = 0.03% to 0.26%) pooled MACE compared to 0.23% (95% CI = 0.01% to 5.8%) of the exercise stress testing (p = 1). MPS and cCTA had an overall event rate of 0.15% (95% CI = 0.06% to 0.41%) at 6 months (I²  = 0%). At 12 months, a subgroup analysis found a pooled cCTA MACE of 0.16% (95% CI = 0.04% to 0.65%) compared to 1.68% (95% CI = 0.01% to 2.6%) for stress echocardiography with low within-group heterogeneity (I²  = 0%). Subgroup analysis of cCTA with no disease versus nonobstructive disease (<50% stenosis) did not find statistical difference in the MACE at both 1 month (0.17% [95% CI = 0.04% to 0.67%] vs. 0.06% [95% CI = 0.01% to 0.34%]) and 12 months (0.44% [95% CI = 0.09% to 2.2% vs. 0.54% [95% CI = 0.19% to 1.5%]).

CONCLUSIONS

Patients presenting with chest pain who have a coronary CTA showing < 50% stenosis, negative ECG stress test, stress echocardiography, or stress myocardial perfusion scan in the past 12 months can be discharged without any further risk stratification if their ECG and troponin are reassuring given low MACE.

Desempenho Diagnóstico da Angiotomografia Computadorizada e da Avaliação Seriada de Troponina Cardíaca Sensível em Pacientes com Dor Torácica e Risco Intermediário para Eventos Cardiovasculares

Fundamento

A angiotomografia coronária (ATC) tem sido usada para avaliação de dor torácica principalmente em pacientes de baixo risco, e poucos dados existem com pacientes em risco intermediário.

Objetivo

Avaliar o desempenho de medidas seriadas de troponinas sensíveis e de ATC em pacientes de risco intermediário.

Métodos

Um total de 100 pacientes com dor torácica, TIMI score 3 ou 4 e troponina negativa foram prospectivamente incluídos. Todos os pacientes foram submetidos à ATC, e aqueles com obstruções ≥ 50% foram encaminhados à cineangiocoronariografia. Pacientes com lesões < 50% recebiam alta hospitalar, receberam alta e foram contatados 30 dias depois por telefonema para avaliação dos desfechos clínicos. Os desfechos foram hospitalização, morte, e infarto agudo do miocárdio em 30 dias. A comparação entre os métodos foi realizada pelo teste de concordância kappa. O desempenho das medidas de troponina e da ATC na detecção de lesões coronárias significativas e desfechos clínicos foi calculado. Os resultados foram considerados estatisticamente significativos quando p <0,05.

Resultados

Estenose coronária ≥ 50% na ATC foi encontrada em 38% dos pacientes e lesões coronárias significativas na angiografia coronária foram encontradas em 31 pacientes. Dois eventos clínicos foram observados. A análise de concordância Kappa mostrou baixa concordância entre as medidas de troponina e ATC na detecção de lesões coronárias significativas (kappa = 0,022, p = 0,78). O desempenho da ATC para detectar lesões coronárias significativas na angiografia coronária ou para prever eventos clínicos em 30 dias foi melhor que as medidas de troponina sensível (acurácia de 91% versus 60%).

Conclusão

ATC teve melhor desempenho que as medidas seriadas de troponina na detecção de doença coronariana significativa em pacientes com dor torácica e risco intermediário para eventos cardiovasculares.

Prognostic Utility of a Modified HEART Score in Chest Pain Patients in the Emergency Department

BACKGROUND

The TRAPID-AMI trial study (High-Sensitivity Troponin-T Assay for Rapid Rule-Out of Acute Myocardial Infarction) evaluated high-sensitivity cardiac troponin-T (hs-cTnT) in a 1-hour acute myocardial infarction (AMI) exclusion algorithm. Our study objective was to evaluate the prognostic utility of a modified HEART score (m-HS) within this trial.

METHODS AND RESULTS

Twelve centers evaluated 1282 patients in the emergency department for possible AMI from 2011 to 2013. Measurements of hs-cTnT (99th percentile, 14 ng/L) were performed at 0, 1, 2, and 4 to 14 hours. Evaluation for major adverse cardiac events (MACEs) occurred at 30 days (death or AMI). Low-risk patients had an m-HS≤3 and had either hs-cTnT<14 ng/L over serial testing or had AMI excluded by the 1-hour protocol. By the 1-hour protocol, 777 (60%) patients had an AMI excluded. Of those 777 patients, 515 (66.3%) patients had an m-HS≤3, with 1 (0.2%) patient having a MACE, and 262 (33.7%) patients had an m-HS≥4, with 6 (2.3%) patients having MACEs (P=0.007). Over 4 to 14 hours, 661 patients had a hs-cTnT<14 ng/L. Of those 661 patients, 413 (62.5%) patients had an m-HS≤3, with 1 (0.2%) patient having a MACE, and 248 (37.5%) patients had an m-HS≥4, with 5 (2.0%) patients having MACEs (P=0.03).

CONCLUSIONS

Serial testing of hs-cTnT over 1 hour along with application of an m-HS identified a low-risk population that might be able to be directly discharged from the emergency department.

Highly sensitive troponin and coronary computed tomography angiography in the evaluation of suspected acute coronary syndrome in the emergency department

The evaluation of patients presenting to the emergency department with suspected acute coronary syndrome (ACS) remains a clinical challenge. The traditional assessment includes clinical risk assessment based on cardiovascular risk factors with serial electrocardiograms and cardiac troponin measurements, often followed by advanced cardiac testing as inpatient or outpatient (i.e. stress testing, imaging). Despite this costly and lengthy work-up, there is a non-negligible rate of missed ACS with an increased risk of death. There is a clinical need for diagnostic strategies that will lead to rapid and reliable triage of patients with suspected ACS. We provide an overview of the evidence for the role of highly sensitive troponin (hsTn) in the rapid and efficient evaluation of suspected ACS. Results of recent research studies have led to the introduction of hsTn with rapid rule-in and rule-out protocols into the guidelines. Highly sensitive troponin increases the sensitivity for the detection of myocardial infarction and decreases time to diagnosis; however, it may decrease the specificity, especially when used as a dichotomous variable, rather than continuous variable as recommended by guidelines; this may increase clinician uncertainty. We summarize the evidence for the use of coronary computed tomography angiography (CTA) as the rapid diagnostic tool in this population when used with conventional troponin assays. Coronary CTA significantly decreases time to diagnosis and discharge in patients with suspected ACS, while being safe. However, it may lead to increase in invasive procedures and includes radiation exposure. Finally, we outline the opportunities for the combined use of hsTn and coronary CTA that may result in increased efficiency, decreased need for imaging, lower cost, and decreased radiation dose.

Long-term outcome after CT angiography in patients with possible acute coronary syndrome

PURPOSE

To assess the long-term outcome and hospital readmission rate associated with a computed tomographic (CT) angiography-guided strategy used to examine patients who present to the emergency department (ED) with symptoms of possible acute coronary syndrome (ACS).

MATERIALS AND METHODS

The study was approved by the institutional review board, and all patients provided written informed consent. A total of 585 consecutive patients (mean age, 58 years ± 11 [standard deviation]; 58% were male) with ischemic-type chest pain and low to intermediate risk for ACS were evaluated prospectively. Patients underwent coronary CT angiography after single or serial troponin I (TnI) measurement, depending on time of presentation to the ED. Subsequent care was determined with CT angiography findings: Patients without plaque and patients with nonobstructive plaque and at most mild to moderate stenosis (<40% luminal narrowing) were discharged without further investigation. Patients with moderate stenosis (40%-70% narrowing) were discharged and referred for outpatient stress echocardiography. Patients with severe stenosis (>70% narrowing) were admitted. Discharged patients were contacted and their medical records were reviewed to determine rates of death, ACS, revascularization, and hospital admission. By using binomial distribution, Clopper-Pearson confidence intervals (CIs) were calculated for outcome data.

RESULTS

Coronary CT angiography findings were as follows: A total of 196 patients (34%) had no coronary plaque or stenosis, 288 (49%) had nonobstructive plaque, 22 (4%) had moderate stenosis, and 79 (13%) had severe stenosis. At median 47.4-month follow-up (range, 24-57 months) of the 506 discharged patients, five (1%; 95% CI: 0.4%, 2.3%) had been readmitted for chest pain; there were no instances of coronary revascularization, ACS, or death (0% for all; 95% CI: 0%, 0.7%). Follow-up was 100% complete.

CONCLUSION

Use of a CT angiography-guided strategy to investigate patients with low to intermediate risk of ACS who present to the ED with chest pain is safe at long-term follow-up, including patients discharged after single TnI measurement.

The approach to patients with possible cardiac chest pain

Chest pain is a common reason for presentation in hospital emergency departments and general practice. Some patients presenting with chest pain to emergency departments and, to a lesser extent, general practice will be found to have a life-threatening cause, but most will not. The challenge is to identify those who do in a safe, timely and cost-effective manner. An acute coronary syndrome cannot be excluded on clinical grounds alone. In patients with ongoing symptoms of chest pain, without an obvious other cause, ST-segment-elevation myocardial infarction should be excluded with a 12-lead electrocardiogram at the first available opportunity. Significant recent advances in the clinical approach to patients with acute chest pain, including better understanding of risk stratification, increasingly sensitive cardiac biomarkers and new non-invasive tests for coronary disease, can help clinicians minimise the risk of unexpected short-term adverse cardiac events. An approach that integrates these advances is needed to deliver the best outcomes for patients with chest pain. All hospital emergency departments should adopt such a strategic approach, and general practitioners should be aware of when and how to access these facilities.

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.

Comparison of traditional cardiovascular risk models and coronary atherosclerotic plaque as detected by computed tomography for prediction of acute coronary syndrome in patients with acute chest pain

OBJECTIVES

The objective was to determine the association of four clinical risk scores and coronary plaque burden as detected by computed tomography (CT) with the outcome of acute coronary syndrome (ACS) in patients with acute chest pain. The hypothesis was that the combination of risk scores and plaque burden improved the discriminatory capacity for the diagnosis of ACS.

METHODS

The study was a subanalysis of the Rule Out Myocardial Infarction Using Computer-Assisted Tomography (ROMICAT) trial-a prospective observational cohort study. The authors enrolled patients presenting to the emergency department (ED) with a chief complaint of acute chest pain, inconclusive initial evaluation (negative biomarkers, nondiagnostic electrocardiogram [ECG]), and no history of coronary artery disease (CAD). Patients underwent contrast-enhanced 64-multidetector-row cardiac CT and received standard clinical care (serial ECG, cardiac biomarkers, and subsequent diagnostic testing, such as exercise treadmill testing, nuclear stress perfusion imaging, and/or invasive coronary angiography), as deemed clinically appropriate. The clinical providers were blinded to CT results. The chest pain score was calculated and the results were dichotomized to ≥10 (high-risk) and <10 (low-risk). Three risk scores were calculated, Goldman, Sanchis, and Thrombolysis in Myocardial Infarction (TIMI), and each patient was assigned to a low-, intermediate-, or high-risk category. Because of the low number of subjects in the high-risk group, the intermediate- and high-risk groups were combined into one. CT images were evaluated for the presence of plaque in 17 coronary segments. Plaque burden was stratified into none, intermediate, and high (zero, one to four, and more than four segments with plaque). An outcome panel of two physicians (blinded to CT findings) established the primary outcome of ACS (defined as either an acute myocardial infarction or unstable angina) during the index hospitalization (from the presentation to the ED to the discharge from the hospital). Logistic regression modeling was performed to examine the association of risk scores and coronary plaque burden to the outcome of ACS. Unadjusted models were individually fitted for the coronary plaque burden and for Goldman, Sanchis, TIMI, and chest pain scores. In adjusted analyses, the authors tested whether the association between risk scores and ACS persisted after controlling for the coronary plaque burden. The prognostic discriminatory capacity of the risk scores and plaque burden for ACS was assessed using c-statistics. The differences in area under the receiver-operating characteristic curve (AUC) and c-statistics were tested by performing the -2 log likelihood ratio test of nested models. A p value <0.05 was considered statistically significant.

RESULTS

Among 368 subjects, 31 (8%) subjects were diagnosed with ACS. Goldman (AUC = 0.61), Sanchis (AUC = 0.71), and TIMI (AUC = 0.63) had modest discriminatory capacity for the diagnosis of ACS. Plaque burden was the strongest predictor of ACS (AUC = 0.86; p < 0.05 for all comparisons with individual risk scores). The combination of plaque burden and risk scores improved prediction of ACS (plaque + Goldman AUC = 0.88, plaque + Sanchis AUC = 0.90, plaque + TIMI AUC = 0.88; p < 0.01 for all comparisons with coronary plaque burden alone).

CONCLUSIONS

Risk scores (Goldman, Sanchis, TIMI) have modest discriminatory capacity and coronary plaque burden has good discriminatory capacity for the diagnosis of ACS in patients with acute chest pain. The combined information of risk scores and plaque burden significantly improves the discriminatory capacity for the diagnosis of ACS.

Integrated diagnostics: proceedings from the 9th biennial symposium of the International Society for Strategic Studies in Radiology

The International Society for Strategic Studies in Radiology held its 9th biennial meeting in August 2011. The focus of the programme was integrated diagnostics and massive computing. Participants discussed the opportunities, challenges, and consequences for the discipline of radiology that will likely arise from the integration of diagnostic technologies. Diagnostic technologies are increasing in scope, including advanced imaging techniques, new molecular imaging agents, and sophisticated point-of-use devices. Advanced information technology (IT), which is increasingly influencing the practice of medicine, will aid clinical communication and the development of “population images” that represent the phenotype of particular diseases, which will aid the development of diagnostic algorithms. Integrated diagnostics offer increased operational efficiency and benefits to patients through quicker and more accurate diagnoses. As physicians with the most expertise in IT, radiologists are well placed to take the lead in introducing IT solutions and cloud computing to promote integrated diagnostics. To achieve this, radiologists must adapt to include quantitative data on biomarkers in their reports. Radiologists must also increase their role as participating physicians, collaborating with other medical specialties, not only to avoid being sidelined by other specialties but also to better prepare as leaders in the selection and sequence of diagnostic procedures.

Key Points

• New diagnostic technologies are yielding unprecedented amounts of diagnostic information.

• Advanced IT/cloud computing will aid integration and analysis of diagnostic data.

• Better diagnostic algorithms will lead to faster diagnosis and more rapid treatment.

Cardiac CT in the emergency department

Current triage strategies are not effective in correctly identifying patients suffering from acute coronary syndrome (ACS). The diagnostic workup of patients presenting with acute chest pain continues to represent a major challenge for emergency department (ED) personnel. This statement holds especially true for patients with a low to intermediate likelihood for ACS. Taking current concepts for the diagnosis and management of patients presenting with acute chest pain to the ED into account, this article discusses the evidence and potential role of coronary computed tomography angiography to improve management of patients with possible ACS.