Prevalence of Acute Coronary Syndrome in Patients Suspected for Pulmonary Embolism or Acute Aortic Syndrome: Rationale for the Triple Rule-Out Concept

ACR Appropriateness Criteria® Suspected Pulmonary Embolism: 2022 Update

Pulmonary embolism (PE) remains a common and important clinical condition that cannot be accurately diagnosed on the basis of signs, symptoms, and history alone. The diagnosis of PE has been facilitated by technical advancements and multidetector CT pulmonary angiography, which is the major diagnostic modality currently used. Ventilation and perfusion scans remain largely accurate and useful in certain settings. MR angiography can be useful in some clinical scenarios and lower-extremity ultrasound can substitute by demonstrating deep vein thrombosis; however, if negative, further studies to exclude PE are indicated. In all cases, correlation with the clinical status, particularly with risk factors, improves not only the accuracy of diagnostic imaging but also overall utilization. Other diagnostic tests have limited roles. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Double rule-out technique for evaluation of acute chest pain using 128-row multidetector CT

AIM

To evaluate the feasibility and image quality of the double rule-out (DRO) technique using 128-row multidetector computed tomography (CT) for simultaneous evaluation of the aorta and coronary arteries in patients with acute non-specific chest pain.

MATERIALS AND METHODS

Sixty-eight patients underwent electrocardiography (ECG)-gated coronary CT followed by non-ECG-gated abdominal CT. The contrast-to-noise ratio and signal-to-noise ratio between the vessels and adjacent perivascular fat tissue were calculated for both the aorta and coronary arteries. Dose-length products were recorded. Two blinded readers graded the image quality of the aorta and coronary arteries on a two-point and a four-point scale, respectively. In addition, the severity of coronary stenosis was independently analysed for each coronary vessel.

RESULTS

The average attenuation was more than 350 HU for the aorta and >330 HU for the coronary arteries. The average (±standard deviation) volume of contrast media was 69.5 ± 12.5 ml. Interobserver agreement on the image quality of aortic and coronary data sets was perfect and substantial, respectively. There was almost perfect interobserver agreement for the all observations of the severity of coronary stenosis.

CONCLUSION

The DRO technique with a standard volume (approximately 70 ml) of contrast media is useful for acute chest pain evaluation in patients suspected of having acute aortic syndrome or acute coronary syndrome. It is also accurate and safe while maintaining the average CT attenuation of the aorta and coronary arteries >330 HU.

Nomogram to differentiate between aortic dissection and non-ST segment elevation acute coronary syndrome: a retrospective cohort study

Background

Aortic dissection (AD) and non-ST segment elevation acute coronary syndrome (ACS) are two of the most life-threatening diseases encountered in the emergency department (ED), but there are no rapid and reliable tools for differentiation. The purpose of this study is to develop and validate a nomogram that incorporates both the clinical characteristics and bedside laboratory tests available to differentiate between AD and non-ST segment elevation ACS (NSTE-ACS).

Methods

Between January 2016 and July 2018, patients with AD and NSTE-ACS were enrolled and divided into training and validation groups. The least absolute shrinkage and selection operator (LASSO) regression model was used to select the factors with significant value of predicting the diagnosis of AD. A nomogram was built on the basis of multivariable logistic regression analysis. Area under the curve (AUC) of receiver operating characteristic (ROC) curve and the calibration curve were used to assess the performance of the nomogram. Decision curve analysis was performed to assess the clinical utility of the nomogram.

Results

A final cohort of 263 patients (94 patients with AD and 169 patients with NSTE-ACS) were enrolled. Six variables were incorporated in the nomogram: pain severity, tearing pain, pulse asymmetry, electrocardiogram (ECG), D-dimer level and troponin I level. The AUC of the nomogram to predict the probability of AD was 0.919 (95% CI, 0.876-0.962) in the training group and 0.938 (95% CI, 0.888-0.989) in the validation group. The calibration curve demonstrated a good consistency between the actual clinical results and the predicted outcomes. The decision curve analysis indicated that the nomogram had higher overall net benefits in predicting AD in both the training group and the validation group.

Conclusions

We developed and validated a predictive nomogram that could be used as a tool to differentiate AD from NSTE-ACS rapidly and accurately.

Chest CT Angiography for Acute Aortic Pathologic Conditions: Pearls and Pitfalls

Chest CT angiography (CTA) is essential in the diagnosis of acute aortic syndromes. Chest CTA quality can be optimized with attention to technical parameters pertaining to noncontrast imaging, timing of contrast-enhanced imaging, contrast material volume, kilovolt potential, tube-current modulation, and decisions regarding electrocardiographic-gating and ultra-fast imaging, which may affect the accurate diagnosis of acute aortic syndromes. An understanding of methods to apply to address suboptimal image quality is useful, as the accurate identification of acute aortic syndromes is essential for appropriate patient management. Acute aortic syndromes have high morbidity and mortality, particularly when involving the ascending aorta, and include classic aortic dissection, penetrating atherosclerotic ulcer, and acute intramural hematoma. An understanding of the pathogenesis and distinguishing imaging features of acute aortic syndromes and aortic rupture and some less common manifestations is helpful when interpreting imaging examinations. Related entities, such as ulcerated plaque, ulcerlike projections, and intramural blood pools, and mimics, such as vasculitis and aortic thrombus, are important to recognize; knowledge of these is important to avoid interpretive pitfalls. In addition, an awareness of postsurgical aortic changes can be useful when interpreting CTA examinations when patient history is incomplete. The authors review technical considerations when performing CTA, discuss acute aortic syndromes, and highlight diagnostic challenges encountered when interpreting aortic CTA examinations. ^©RSNA, 2021.

Computed Tomographic Angiography for Risk Stratification in Patients with Acute Chest Pain - The Triple Rule-out Concept in the Emergency Department

BACKGROUND

Acute chest pain is one of the most common reasons for Emergency Department (ED) visits and hospital admissions. As this could represent the first symptom of a lifethreatening condition, urgent identification of the etiology of chest pain is of utmost importance in emergency settings. Such high-risk conditions that can present with acute chest pain in the ED include Acute Coronary Syndromes (ACS), Pulmonary Embolisms (PE) and Acute Aortic Syndromes (AAS).

DISCUSSION

The concept of Triple Rule-out Computed Tomographic Angiography (TRO-CTA) for patients presenting with acute chest pain in the ED is based on the use of coronary computed tomographic angiography as a single imaging technique, able to diagnose or exclude three lifethreatening conditions in one single step: ACS, AAS and PE. TRO-CTA protocols have been proved to be efficient in the ED for diagnosis or exclusion of life-threatening conditions and for differentiation between various etiologies of chest pain, and application of the TRO-CTA protocol in the ED for acute chest pain of uncertain etiology has been shown to improve the further clinical evaluation and outcomes of these patients.

CONCLUSION

This review aims to summarize the main indications and techniques used in TRO protocols in EDs, and the role of TRO-CTA protocols in risk stratification of patients with acute chest pain.

Cardiac Computed Tomography in Certified German Chest Pain Units

OBJECTIVE

The German Cardiac Society runs a nation-wide certification campaign for specialized chest pain units (CPUs). So far, cardiac computed tomography (CT) is not an integral part of such certification. The aim of our study was to analyze whether or not cardiac CT is nevertheless routinely used for further stratification in low-risk patients.

METHODS

For the time interval from January 2010 to April 2011, data were retrieved from the mandatory German CPU registry. Patients with and without cardiac CT during CPU index stay were compared.

RESULTS

Out of 5800 patients, 314 patients (5.4%) underwent cardiac CT during the index CPU stay. Unstable angina pectoris was the most common diagnosis when performing cardiac CT [34.4% vs. 17.7%; odds ratio (OR), 2.44; confidence interval (CI), 1.91-3.11; P < 0.001). Patients undergoing cardiac CT received significantly less often coronary angiography (31.8% vs. 54.8%; OR, 0.39; CI, 0.30-0.49; P < 0.001) or coronary revascularization (15.6% vs. 36.5%; OR, 0.32; CI, 0.23-0.46; P < 0.001). The use of cardiac CT did not prolong the length of stay in the CPU (20:48 vs. 20:25 h, P = 0.21).

CONCLUSIONS

Cardiac CT is underrepresented within the diagnostic work up in certified CPUs in Germany, although its use reduces unnecessary invasive diagnostics. The use of cardiac CT should be reconsidered during the next update of the CPU certification criteria.

Assessment of myocardial enhancement during coronary CT angiography in critically ill patients

There are still challenges and unmet needs for the imaging techniques, such as conditions of uncertain origin in patients with clinically serious, life-threatening conditions with unknown cause that are not associated with dominant chest pain, ECG changes or other symptoms indicating a possible primarily cardiac or coronary cause. The contribution of the myocardial enhancement evaluation of urgent cardiac CTA scans significantly improves to determining the diagnosis of acute myocardial injury and choosing appropriate treatment. When incorporating the myocardial enhancement assessment into the imaging algorithm of an emergency department, emphasis is placed on a uniform imaging procedure and a uniform evaluation approach. The color coded images of the myocardial enhancement in emergency situations helps identify the most serious pathologies and shorten the time to adequate targeted therapy in patients.