Rapid diagnosis and management of thoracic aortic dissection and intramural haematoma: a prospective study of advantages of multiplane vs. biplane transoesophageal echocardiography

Acute Aortic Syndromes from Diagnosis to Treatment-A Comprehensive Review

This work aims to provide a comprehensive description of the characteristics of a group of acute aortic diseases that are all potentially life-threatening and are collectively referred to as acute aortic syndromes (AASs). There have been recent developments in the care and diagnostic plan for AAS. A substantial clinical index of suspicion is required to identify AASs before irreversible fatal consequences arise because of their indefinite symptoms and physical indicators. A methodical approach to the diagnosis of AAS is addressed. Timely and suitable therapy should be started immediately after diagnosis. Improving clinical outcomes requires centralising patients with AAS in high-volume centres with high-volume surgeons. Consequently, the management of these patients benefits from the increased use of aortic centres, multidisciplinary teams and an "aorta code". Each acute aortic entity requires a different patient treatment strategy; these are outlined below. Finally, numerous preventive strategies for AAS are discussed. The keys to good results are early diagnosis, understanding the natural history of these disorders and, where necessary, prompt surgical intervention. It is important to keep in mind that chest pain does not necessarily correspond with coronary heart disease and to be alert to the possible existence of aortic diseases because once antiplatelet drugs are administered, a blocked coagulation system can complicate aortic surgery and affect prognosis. The management of AAS in "aortic centres" improves long-term outcomes and decreases mortality rates.

The Role of Multimodality Imaging Approach in Acute Aortic Syndromes: Diagnosis, Complications, and Clinical Management

Acute aortic syndromes are life-threatening conditions with high morbidity and mortality. The principal pathological feature is acute wall damage with possible evolution towards aortic rupture. Accurate and timely diagnosis is mandatory to avoid catastrophic consequences. Indeed, misdiagnosis with other conditions mimicking acute aortic syndromes is associated with premature death. In this view, cardiovascular imaging is necessary for the correct diagnosis and management. Echocardiography, computed tomography, magnetic resonance imaging, and aortography allow for diagnosis, guarantee immediate treatment, and detect associated complications. Multimodality imaging is essential in the diagnostic work-up to confirm or rule out acute aortic syndromes. The aim of this review is to highlight the contemporary evidence on the role of single cardiovascular imaging techniques and multimodality imaging in the diagnosis and management of acute aortic syndromes.

Diagnosis and Management of Acute Aortic Syndromes: Dissection, Penetrating Aortic Ulcer, and Intramural Hematoma

PURPOSE OF REVIEW

Acute aortic syndromes, including aortic dissection, intramural hematoma, and penetrating aortic ulcer, are a group of highly morbid, related pathologies that are defined by compromised aortic wall integrity. The purpose of this review is to summarize current management strategies for acute aortic syndromes.

RECENT FINDINGS

All acute aortic syndromes have potential for high morbidity and mortality and must be quickly identified and managed with the appropriate algorithm to prevent suboptimal outcomes. Recent trials suggest that TEVAR is increasingly useful in stabilizing pathology of the descending thoracic aorta but when possible should be applied in a delayed fashion and with limited coverage to minimize neurologic complications. Treatment for acute aortic syndrome is frequently dictated by the anatomic location and extent of the wall compromise as well as patient comorbidities. Therapy is often individualized and often includes some combination of medical, procedural, and surgical intervention.

Use of aortic point-of-care ultrasound in conventional and emergent echocardiography

Aortic aneurysms expand asymptomatically and rupture lethally. Acute aortic dissection is also a highly lethal cardiovascular emergency and requires prompt recognition. Although cardiovascular ultrasonography has a suboptimal accuracy rate for detecting aortic dissection, it is noninvasive, readily available, and easy to use. Recently, the concept of point-of-care ultrasound (POCUS) refers to the use of portable and/or implemented ultrasound at the patient's bedside for diagnostic and therapeutic purposes. Aortic POCUS could become an important tool for aortic aneurysm screening and primary diagnosis of acute aortic dissection.

Diagnosing Aortic Intramural Hematoma: Current Perspectives

Aortic intramural hematoma (AIH) is an entity within the acute aortic syndrome. Combination of a priori probability, clinical history, laboratory blood test and imaging techniques are the basis for diagnosis of AIH. This review is focused on all aspects related to diagnosis of patients with AIH, from clinical to imaging and analytical.

The current role of echocardiography in acute aortic syndrome

Acute aortic syndrome (AAS) comprises a range of interrelated conditions caused by disruption of the medial layer of the aortic wall, including aortic dissection, intramural haematoma and penetrating aortic ulcer. Since mortality from AAS is high, a prompt and accurate diagnosis using imaging techniques is paramount. Both transthoracic (TTE) and transoesophageal echocardiography (TEE) are useful in the diagnosis of AAS. TTE should be the first imaging technique to evaluate patients with thoracic pain in the emergency room. Should AAS be suspected, contrast administration is recommended when images are not definitive. TEE allows high-quality images in thoracic aorta. The main drawback of this technique is that it is semi-invasive and the presence of a blind area that limits visualisation of the distal ascending aorta near. TEE identifies the location and size of the entry tear, secondary communications, true lumen compression and the dynamic flow pattern of false lumen. Although computed tomography (CT) is the most used imaging technique in the diagnosis of AAS, echocardiography offers complementary information relevant for its management. The best imaging strategy for appropriately diagnosing and assessing AAS is to combine CT, mainly ECG-gated contrast-enhanced CT, and TTE. Currently, TEE tends to be carried out in the operating theatre immediately before surgical or endovascular therapy and in monitoring their results. The aims of this review are to establish the current role of echocardiography in the diagnosis and management of AAS based on its advantages and limitations.

Ultrasound in cardiac trauma

In the perioperative period, the emergency department or the intensive care unit accurate assessment of variable chest pain requires meticulous knowledge, diagnostic skills, and suitable usage of various diagnostic modalities. In addition, in polytrauma patients, cardiac injury including aortic dissection, pulmonary embolism, acute myocardial infarction, and pericardial effusion should be immediately revealed and treated. In these patients, arrhythmias, mainly tachycardia, cardiac murmurs, or hypotension must alert physicians to suspect cardiovascular trauma, which would potentially be life threatening. Ultrasound of the heart using transthoracic and transesophageal echocardiography are valuable diagnostic tools that can be used interchangeably in conjunction with other modalities such as the electrocardiogram and computed tomography for the diagnosis of cardiovascular abnormalities in trauma patients. Although ultrasound of the heart is often underused in the setting of trauma, it does have the advantages of being easily accessible, noninvasive, and rapid bedside assessment tool. This review article aims to analyze the potential cardiac injuries in trauma patients, and to provide an elaborate description of the role of echocardiography for their accurate diagnosis.

Intraoperative Echocardiography: Support for Decision Making in Cardiac Surgery

Intraoperative echocardiography (including transesophageal echocardiography, epiaortic ultrasound and epicardial echocardiography) is commonly performed in North American hospitals during cardiac anesthesia. Several authors have reported on the positive impact of intraoperative echocardiography on patients’ outcomes. Transesophageal echocardiography is useful in identifying anatomic and functional abnormalities either before or after cardiopulmonary bypass and helps to make decisions in the care of high-risk and unstable patients. In minimally invasive and robotically assisted surgery, transesophageal echocardiography is essential in order to guide cannulation of venous and arterial vessels for cardiopulmonary bypass and in providing immediate assessment of the quality of the performed repair. Intraoperative echocardiography can also detect complications associated with the performed procedure and can be an excellent hemodynamic monitor in unstable patients. In this paper different scenarios where intraoperative echocardiography is useful are reviewed, some clinical cases are shown to illustrate, and a review of related literature is reported.

A patient-specific study of type-B aortic dissection: evaluation of true-false lumen blood exchange

Background

Aortic dissection is a severe pathological condition in which blood penetrates between layers of the aortic wall and creates a duplicate channel – the false lumen. This considerable change on the aortic morphology alters hemodynamic features dramatically and, in the case of rupture, induces markedly high rates of morbidity and mortality.

Methods

In this study, we establish a patient-specific computational model and simulate the pulsatile blood flow within the dissected aorta. The k-ω SST turbulence model is employed to represent the flow and finite volume method is applied for numerical solutions. Our emphasis is on flow exchange between true and false lumen during the cardiac cycle and on quantifying the flow across specific passages. Loading distributions including pressure and wall shear stress have also been investigated and results of direct simulations are compared with solutions employing appropriate turbulence models.

Results

Our results indicate that (i) high velocities occur at the periphery of the entries; (ii) for the case studied, approximately 40% of the blood flow passes the false lumen during a heartbeat cycle; (iii) higher pressures are found at the outer wall of the dissection, which may induce further dilation of the pseudo-lumen; (iv) highest wall shear stresses occur around the entries, perhaps indicating the vulnerability of this region to further splitting; and (v) laminar simulations with adequately fine mesh resolutions, especially refined near the walls, can capture similar flow patterns to the (coarser mesh) turbulent results, although the absolute magnitudes computed are in general smaller.

Conclusions

The patient-specific model of aortic dissection provides detailed flow information of blood transport within the true and false lumen and quantifies the loading distributions over the aorta and dissection walls. This contributes to evaluating potential thrombotic behavior in the false lumen and is pivotal in guiding endovascular intervention. Moreover, as a computational study, mesh requirements to successfully evaluate the hemodynamic parameters have been proposed.

Imaging modalities for the early diagnosis of acute aortic syndrome

The term acute aortic syndrome (AAS) incorporates aortic dissection, intramural haematoma, and penetrating atherosclerotic ulcer. The common feature of these entities is disruption of the medial layer of the aortic wall. Owing to the life-threatening nature of these conditions, prompt and accurate diagnosis is of paramount importance--misdiagnosis can be fatal. The noninvasive imaging techniques that have a fundamental role in the diagnosis and management of patients with AAS include CT, MRI, transoesophageal echocardiography (TEE), and transthoracic echocardiography (TTE). CT is the most-commonly used imaging modality owing to its wide availability, accuracy, and large field of view. CT plus TTE is the best combination for diagnosing AAS and its complications, and allows important morphological and dynamic aspects of AAS to be assessed and appropriately managed. Ideally, TEE should be performed immediately before surgery or endovascular treatment, in the operating theatre and under general anaesthesia. In stable patients with an uncertain diagnosis of intramural haematoma despite high clinical suspicion, MRI is the technique of choice to make a definitive diagnosis. Imaging techniques have an important role in the primary diagnosis, treatment strategy, and risk stratification of patients with AAS.

Current imaging techniques and potential biomarkers in the diagnosis of acute aortic dissection

Acute dissection of the thoracic aorta (AAD) is a potentially catastrophic disease, with significant morbidity and mortality, which remain unchanged over the last decade. Survival rate has been shown to be directly related to prompt diagnosis and precise management; however diagnosis of the disease remains time-consuming, not readily available, and lacking in sensitivity and specificity. The current approach when diagnosing AAD relies heavily on various imaging techniques, including chest radiograph, echocardiography, computed tomography and magnetic resonance imaging scans. Nevertheless, the door remains open for the incorporation of biochemical tests to aid in detecting AAD. This article will review the imaging modalities currently employed in the management of AAD, as well as a discussion of the potential role of several biomarkers in AAD. To date, imaging is the diagnostic tool for AAD however, technical and logistical limitations limit the use of imaging in various circumstances. Current available biomarkers such as D-dimer and C-reactive protein are under-utilized in many cases, mainly due to their non-specificity in diagnosing AAD. Over the last decade, many biomarkers have been proposed for use in AAD, with several showing promising results – including: smooth muscle myosin heavy chain, calponin, soluble elastin fragments and transforming growth factor β. Extensive research is being undertaken to define the roles of these novel biomarkers in the management of AAD.

Cocaine and aortic dissection

Aortic dissection is a rare, potentially catastrophic vascular emergency. Early recognition of the clinical manifestations, rapid confirmation using imaging modalities, urgent administration of appropriate medication and expedient selection of definitive long-term therapy are key to preserving life and reducing morbidity. In recent years it has become increasingly clear that there is a relation between cocaine and aortic dissection. Cocaine serves as both a predisposing factor to aortic dissection due to its effect on aortic connective tissue and as a precipitating factor due to its propensity to produce abrupt and severe hypertension. While similarities exist in the clinical features and diagnostic methods between cocaine-related aortic dissection and aortic dissection unrelated to cocaine use, there are important differences in management between these two syndromes which are rooted in the pharmacology and physiology of cocaine. An understanding of these differences is key to effective early and long-term management of cocaine-related aortic dissection.

The utility of multiple imaging modalities to diagnose acute aortic dissection

A 21-year-old man with Marfan syndrome and known aortic root aneurysm presented to our emergency department with symptoms suggestive of acute aortic dissection. The patient was hemodynamically stable and bilateral upper extremity blood pressures were similar. There was no mediastinal widening on portable chest radiograph. Both contrast CT and retrograde angiography of the aorta failed to identify dissection. Subsequent transesophageal echocardiography demonstrated a Stanford classification type A dissection. This case demonstrates the utility of multiple imaging modalities for identifying aortic dissection in high-risk patients.

International Heterogeneity in Diagnostic Frequency and Clinical Outcomes of Ascending Aortic Intramural Hematoma

BACKGROUND

Differing diagnostic frequencies and management strategies for intramural hematoma (IMH) have been described in North American (NA)/European and Japanese/Korean studies.

METHODS

All publications including type-A aortic IMH were reviewed for details on patient demographics, treatment strategy, and clinical outcomes. Publications were stratified by the geographic region (NA/Europe or Japan/Korea).

RESULTS

IMH, as a percentage of aortic dissection, occurs more frequently in Japan/Korea versus NA/Europe (31.7% vs 10.9%, P < .0001). The proportion of patients treated with early medical therapy is greater in Japanese/Korean studies (77.9% vs 48.8% in NA/Europe, P < .0001). However, the overall mortality is significantly lower in Japan/Korea compared with NA/Europe (9.4% vs 20.6%, odds ratio = 2.80, P = .003) in part because of the lower mortality with early medical therapy (7.8% vs 33.3%, P < .0001).

CONCLUSION

There is significant international heterogeneity in the diagnosis and clinical outcomes of ascending IMH. IMH is diagnosed more frequently and has better overall outcomes in Japan/Korea.

Comparison of feasibility and accuracy of transthoracic echocardiography versus computed tomography in patients with known ascending aortic aneurysm

Aortic valve diseases, hypertension, and connective tissue disorders may be causes of ascending aortic aneurysms. Aortic enlargement monitoring is essential for surgical timing and for operative design. In this regard, several imaging techniques may have limitations: magnetic resonance is not widespread and is expensive, computed tomography uses radiation, and transesophageal echocardiography is a semi-invasive method. The aim of this study was to analyze the feasibility of transthoracic echocardiography in the evaluation of aortic dimensions and its accuracy in comparison with multidetector computed tomography. In 44 patients with known ascending aortic aneurysms, transthoracic echocardiographic and computed tomographic measurements were obtained and compared at different levels: the annulus, sinuses of Valsalva, sinotubular junction, ascending aorta, and aortic arch. Transthoracic echocardiographic diameters were obtained in all patients, apart from the aortic arch, which was measured in 40 cases. Transthoracic echocardiographic and computed tomographic diameters correlated significantly (p <0.001), with very small SEEs: for the annulus, r = 0.846 (SEE 0.37); for the sinuses of Valsalva, r = 0.967 (SEE 0.35); for the sinotubular junction, r = 0.965 (SEE 0.33); for the ascending aorta, r = 0.976 (SEE 0.41); and for the aortic arch, r = 0.87 (SEE 0.50). In conclusion, transthoracic echocardiography is a feasible and accurate technique for the assessment and follow-up of thoracic aortic diameters in patients with ascending aortic aneurysms.

Aortic intramural hematoma: a case report of spontaneous resolution

Aortic intramural hematoma is an acute aortic syndrome caused by hemorrhage within the aortic wall and characterized by the absence of an intimal tear and false lumen, which are the main features of classic aortic dissection. Although surgical intervention represents the standard management of type A aortic intramural hematoma, the possibility of treating some patients with medical therapy associated with serial imaging evaluations at follow-up has recently been demonstrated.

Comment, quand et pourquoi réaliser une imagerie de l’aorte thoracique chez l’adulte ?

CT, MRI and transesophageal echocardiography have become the standard of reference for evaluation of the thoracic aorta. Angiography is mainly performed as a presurgical procedure. Congenital pathologies observed during adulthood include coarctation, patent ductus arteriosus, and aberrant retroesophageal subclavian arteries. Imaging plays a major role for diagnosis and management of patients with acute aortic syndromes: intramural hematoma, dissection, penetrating ulcer and nondissecting aneurysms. Cross sectional imaging of the thoracic aortic wall allows evaluation of inflammatory diseases of the aorta or aortitis.

Current State of Intraoperative Echocardiography

Intraoperative use of echocardiography is becoming more prevalent and is now considered an essential part of modern cardiac surgery. Echocardiography can be performed intraoperatively using transesophageal, epicardial or epiaortic, and substernal approaches. These techniques have a variety of applications in evaluating myocardial and valvular function, assessing aortic atheroma, and determining adequacy of various kinds of repair and reconstruction. Future applications will most likely involve more compact equipment, the implementation of epicardial and transesophageal real-time three-dimensional echocardiography, and better use of provocative methods of intraoperative testing.

Overview of transesophageal echocardiography for the chest physician

Transesophageal echocardiography (TEE) is a growing technology that is frequently utilized in the critical care setting by intensivists, surgeons, anesthesiologists as well as specialists in cardiovascular diseases. The clinical application of TEE continues to emerge, and the indications and diagnostic utility of this technology as currently available are summarized in this review.