Emergency Bedside Ultrasound Diagnosis of Superior Mesenteric Artery Dissection Complicating Acute Aortic Dissection

Background

A timely diagnosis of aortic dissection is associated with lower mortality. The use of emergent bedside ultrasound has been described to diagnose aortic dissection. However, there is limited literature regarding the use of bedside ultrasound to identify superior mesenteric artery dissection, a known high-risk feature of aortic dissection.

Objective

Our aim was to present a case of superior mesenteric artery dissection identified by bedside ultrasound and review the utility of bedside ultrasound in the diagnosis of aortic emergencies.

Case Report

We report a case of superior mesenteric artery dissection found on emergent bedside ultrasound in a 46-year-old male complaining of abdominal pain with a history of cocaine abuse and prior aortic dissection. Bedside ultrasound in the emergency department revealed an intimal flap in the descending aorta with extension into the superior mesenteric artery prompting early surgical consultation before computed tomography because of concern for acute mesenteric ischemia.

Conclusion

Superior mesenteric artery dissection is a high-risk feature of aortic dissection and can be identified with emergent bedside ultrasound.     

Focused Cardiac Ultrasound Diagnosis of Thoracic Aortic Aneurysm: Two Cases

Background

Thoracic aortic aneurysms (TAAs) are less prevalent than abdominal aortic aneurysms. Symptomatic TAAs need to be identified quickly by the emergency physician (EP) since mortality rates increase dramatically once complications such as rupture or dissection occur. Compared with validated EP-performed ultrasound of the abdominal aorta, EP-performed focused cardiac ultrasound that includes evaluation of the thoracic aorta is relatively unreported.

Objective

Two cases illustrate EP-performed focused cardiac ultrasound and evaluation of the thoracic aorta for aneurysmal dilation.

Case Reports

(1) A 60-year-old man presented to the emergency department (ED) after a blunt traumatic injury to his back while at work. During the focused cardiac ultrasound examination, the aortic outflow tract distal to the aortic valve appeared enlarged and the aortic root measured 5.49 cm. (2) An 82-year-old man with hypertension presented to the ED with 1 month of chest pain radiating to the back. The focused cardiac ultrasound examination demonstrated enlargement of the descending thoracic aorta at 4.82 cm.

Conclusion

EPs performing focused cardiac ultrasound can visualize regions of the thoracic aorta that may reveal an aneurysm, particularly in the parasternal long axis view.     

主动脉夹层经胸超声心动图漏诊及误诊原因分析

摘要：目的：探讨主动脉夹层超声表现及部分病例漏诊误诊原因。方法：收集经手术证实为主动脉夹层诊断的病例50例进行回顾分析。结果：手术证实升主动脉夹层36处,主动脉弓夹层29处,降主动脉夹层43处。超声心动图对降主动脉病变漏诊16处,对主动脉弓病变漏诊9处,对升主动脉处病变漏诊1处。漏诊导致对主动脉夹层Debakey分型错误,I型夹层误诊16例,II型夹层误诊0例,III型夹层误诊1例。结论：主动脉夹层漏诊数量由高至低依次为降主动脉、主动脉弓、升主动脉,漏诊及误诊与超声医师因素、超声图像及设备因素密切相关。     

Review article: Accuracy of emergency physician performed point-of-care ultrasound of the thoracic aorta: A systematic review and narrative synthesis of the literature

Point-of-care ultrasound (POCUS) is becoming ubiquitous in emergency medicine. POCUS for abdominal aortic aneurysm is well established in practice. The thoracic aorta can also be assessed by POCUS for dissection and aneurysm and transthoracic echocardiography is endorsed by international guidelines as an initial test for thoracic aortic pathologies. A systematic search of Ovid Medline, PubMed, EMBASE, SCOPUS and Web of Science from January 2000 to August 2022 identified four studies evaluating diagnostic accuracy of emergency physician POCUS for thoracic aortic dissection (TAD) and five studies for thoracic aortic aneurysm (TAA). Study designs were heterogeneous including differing diagnostic criteria for aortic pathology. Convenience recruitment was frequent in prospective studies. Sensitivity and specificity ranges for studies of TAD were 41–91% and 94–100%, respectively when an intimal flap was seen. Sensitivity and specificity ranges for studies of thoracic aorta dilation >40 mm were 50–100% and 93–100%, respectively; for >45 mm ranges were 64–65% and 95–99%. Literature review identified that POCUS is specific for TAD and TAA. POCUS reduces the time to diagnosis of thoracic aortic pathology; however, it remains insensitive and cannot be recommended as a stand-alone rule-out test. We suggest that detection of thoracic aorta dilation >40 mm by POCUS at any site increases the suspicion of serious aortic pathology. Studies incorporating algorithmic use of POCUS, Aortic Dissection Detection Risk Score and D-dimer as decision tools are promising and may improve current ED practices. Further research is warranted in this rapidly evolving field.     

彩色多普勒血流成象在腹主动脉瘤诊断中的应用

本文回顾性分析了２５例既往行超声检查经手术证实的腹主动脉瘤的超声表现。用常规超声检查可鉴别真性腹主动脉瘤，假性腹主动脉瘤以及主动脉夹层瘤。而且通过彩色多普勒成象和频谱多普勒还可识别主动脉夹层瘤的真腔和假腔。超声检查可用于正确诊断腹主动脉瘤。     

Point‐of‐care Focused Cardiac Ultrasound for the Assessment of Thoracic Aortic Dimensions,Dilation, and Aneurysmal Disease

Objectives: Thoracic aortic aneurysm and thoracic aortic dissection are related and potentially deadly diseases that present with nonspecific symptoms. Transthoracic echocardiography (TTE) may detect thoracic aortic pathology and is being increasingly performed by the emergency physician at the bedside; however, the accuracy of point‐of‐care (POC) focused cardiac ultrasound (FOCUS) for thoracic aortic aneurysm and thoracic aortic dissection has not been studied. The objective of this pilot study was to explore the agreement, sensitivity, and specificity of FOCUS for thoracic aortic dimensions, dilation, and aneurysm compared with CT angiography (CTA) as the reference standard. Methods: This study was a retrospective pilot analysis of image and chart data on consecutive patients presenting to an urban, academic emergency department (ED) between January 2008 and June 2010, who had both a FOCUS and a CTA for suspicion of thoracic aorta pathology. Thoracic aorta dimensions were measured from recordings by three ultrasound‐trained emergency physicians blinded to any initial FOCUS and CTA results. CTA measurements were obtained by a radiologist blinded to the FOCUS results. Using cutoffs of 40 and 45 mm, we calculated the sensitivity and specificity of FOCUS for aortic dilation and aneurysm with the largest measurement on CT as the reference standard. Bland‐Altman plots with 95% limits of agreement were used to demonstrate agreement for aortic measurements, kappa statistics to assess the degree of agreement between tests for aortic dilation, and intraclass correlation for interobserver and intraobserver variability. Results: Ninety‐two patients underwent both FOCUS and CTA during the study period. Ten FOCUS studies had inadequate visualization for all measurements areas. Eighty‐two patients were included in the final analysis. Mean (±SD) age was 58.1 (±16.6) years and 58.5% were male. Sensitivity, specificity, and the observed kappa value (95% confidence interval [CI]) between FOCUS and CTA for the presence of aortic dilation at the 40‐mm cutoff were 0.77 (95% CI = 0.58 to 0.98), 0.95 (95% CI = 0.84 to 0.99), and 0.74 (95% CI = 0.58 to 0.90), respectively. The mean difference (95% limits of agreement) for the Bland‐Altman plots was 0.6 mm (?5.3 to 6.5) for the sinuses of Valsalva, 4 mm (?2.7 to 10.7) for the sinotubular junction, 1.5 mm (?5.8 to 8.8) for the ascending aorta, and 2.2 mm (?5.9 to 10.3) for the descending aorta. Conclusions: In this retrospective pilot study, FOCUS demonstrated good agreement with CTA measurements of maximal thoracic aortic diameter. FOCUS appears to be specific for aortic dilation and aneurysm when compared to CTA, but requires further prospective study. ACADEMIC EMERGENCY MEDICINE 2012; 19 :1–4 © 2012 by the Society for Academic Emergency Medicine     

Ultrasound diagnosis of acute thrombosis of an abdominal aortic aneurysm: a case report

Background

Point-of-care ultrasound is an effective and reliable method to diagnosis the presence of an abdominal aortic aneurysm. However, there has been limited literature regarding ultrasound diagnosis of acute aortic thrombosis.

Objective

Discuss a patient case with acute aortic thrombosis diagnosed by point-of-care emergency ultrasound. Review common etiologies and treatment options in this rare diagnosis.

Case Report

A patient with a known abdominal aortic aneurysm presented with mottled lower extremities. Point-of-care ultrasound was utilized by her physicians to diagnose acute thrombosis of her abdominal aorta. With conservative treatment the patient survived to hospital discharge.

Conclusion

Aortic thrombosis is a rare and devastating problem that can be diagnosed with point-of-care ultrasound.     

Aortic valve commissural tear mimicking type A aortic dissection.

A 52-year-old man came to the local emergency department with symptoms of heart failure and transient chest pain. Transthoracic echocardiography showed severe aortic regurgitation and a dilated ascending aorta. Aortic dissection was suspected, and he was transferred to our institution. Transesophageal echocardiography appeared to confirm the presence of a type A dissection. A mobile, linear structure was present in the proximal ascending aorta, suggesting the presence of dissection flap. Aortic cusp prolapse and severe aortic regurgitation were seen. At surgery, no aortic dissection was present. Rather, the commissure between right and left aortic valve cusps was separated from the wall of the aorta. Motion of the torn commissure with the cardiac cycle apparently led to the transesophageal echocardiographic appearance described. The ascending aorta was dilated. Histopathologic examination of the aorta confirmed the visual appearance of cystic medial necrosis. Aortic valve commissural tear is a rare event, which may lead to severe aortic regurgitation. This entity may lead to the false-positive transesophageal echocardiographic diagnosis of type A dissection.     

A successful treatment of cardiac tamponade due to an aortic dissection using open-chest massage

An 81-year-old woman became unconsciousness after complaining of a backache, and then, an ambulance was called. She was suspected to have an aortic dissection by the emergency medical technicians and was transferred to our department. On arrival, she was in shock. Emergency cardiac ultrasound disclosed good wall motion with cardiac tamponade but no complication of aortic regurgitation. Computed tomography of the trunk revealed a type A aortic dissection with cardiac tamponade. During performance of pericardial drainage, she lapsed into cardiopulmonary arrest. Immediately after sterilization of the patient's upper body with compression of the chest wall, we performed a thoracotomy and dissolved the cardiac tamponade by pericardiotomy and obtained her spontaneous circulation. Fortunately, blood discharge was ceased immediately after controlling her blood pressure aggressively. As she complicated pneumonitis, conservative therapy was performed. Her physical condition gradually improved, and she finally could feed herself and communicate. In cases of acute cardiac tamponade, simple pericardiocentesis often is not effective due to the presence of the clot, and a cardiac tamponade by a Stanford type A aortic dissection is highly possible to complicate cardiac arrest, so emergency physicians should be ready to provide immediate open cardiac massage to treat such patients.     

Painless limited dissection of the ascending aorta presenting with aortic valve regurgitation

Aortic dissection is a medical emergency carrying high morbidity and mortality. Prompt diagnosis is sometimes difficult because of its varying presentations, but it is critical to the achievement of good clinical outcomes. This report describes 2 cases of painless aortic dissection that presented with aortic valve regurgitation. In both, the dissection was limited to the ascending aorta just distal to the aortic valve. These dissections were diagnosed by transthoracic and transesophageal echocardiography.     

Ultrasound by emergency physicians to detect abdominal aortic aneurysms: a UK case series

Early identification of abdominal aortic aneurysms in some patients can be difficult and the diagnosis is missed in up to 30% of patients. Ultrasound cannot be used to identify a leak, but the presence of an aneurysm in an unstable patient is conclusive. With minimal training emergency physicians can easily identify the aorta and thus in the early phase of resuscitation an aneurysm can be confidently excluded. The purpose of the examination is not to delineate the extent of the aneurysm, but to identify those patients that will need emergency surgery. A series of patients presented to the department in an unstable condition with equivocal abdominal signs. An ultrasound scan in the resuscitation room by members of the emergency department revealed an aneurysm, which was enough to convince the vascular surgeons to take the patient straight to theatre with good results. In patients who are stable, computed tomography will continue to be used to evaluate the extent of the aneurysm and identify a leak.     

COMMON FEMORAL ARTERY FENESTRATION IN THE TREATMENT OF THORACIC AORTIC DISSECTION

SUMMARY Although dissection of the thoracic aorta is a common aortic emergency, little has been written about fenestration procedures to revascularise femoral arteries that have been occluded by dissecting aneurysms arising from as high as the thoracic aorta.     

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.     

A prospective study of ultrasonography in the ED by emergency physicians

The objective of this study was to examine the use of limited, goal-directed, two-dimensional ultrasound studies performed by emergency physicians and to assess the frequency, variety, and accuracy of their readings. A 1-year prospective study was performed by using an emergency department (ED) ultrasound machine with a 3.5-mHz mechanical oscillating sector transducer and a 5.0-mHz vaginal transducer. In a series of proctoring sessions, radiologists trained emergency physicians to do limited, goal-directed ultrasonography. Laser print ultrasonograms were collected from all ED ultrasound examinations performed during a 1-year period and were compared with either formal ultrasonograms performed in the radiology department, the patient's hospital record, or both. Sensitivity, specificity, and positive predictive value (PPV), as well as negative predictive values (NPV), were calculated. The setting was a 104-bed community hospital with an ED volume of 25,000 patients annually, and patients whom the emergency physician belleved needed ultrasound studies in the ED were entered. ED ultrasonography was performed in 167 patients by 14 physicians during a 1-year period. For 132 patients who completed formal follow-up, the overall diagnostic accuracy of interpretations of ED ultrasonograms yielded a sensitivity of .95, specificity of .98, PPV of .99, and NPV of .89. Eleven categories of ultrasound use were reported. The three studies most commonly performed were for gallbladder disease (53%), intrauterine pregnancy (28%), and abdominal aortic aneurysms (7%). Accuracy of ED gallbladder ultrasonograms for 65 patients showed a sensitivity of .86, specificity of .97, PPV of .97, and NPV of .85. No false-positive or false-negative results were found for ED ultrasonography performed in 42 patients for intrauterine pregnancy or 11 patients for abdominal aortic aneurysms. With appropriate training, emergency physicians can perform diagnostic ultrasound studies with a high degree of accuracy.     

Dissection of the proximal thoracic aorta: a new ultrasonographic sign in the subxiphoid view

Dissection of the thoracic aorta is a life-threatening event that presents with some regularity to emergency departments (EDs). Despite often nonspecific symptoms, it is critical to catch this disease process early, especially when the proximal aorta is involved because dissections involving the aortic root can lead to myocardial infarction and failure of the aortic valve resulting in death. Current imaging options include contrast-enhanced chest computed tomography (CT), angiography, magnetic resonance imaging, or transesophageal echocardiography. Although not as accurate as transesophageal echocardiography, transthoracic echocardiography (TTE) can be used to detect aortic dissection as well. We present a previously undescribed echocardiographic finding associated with proximal dissection of the thoracic aorta in 7 cases.     

Seeing the invisible: painless aortic dissection in the emergency setting

Acute dissection of the aorta can be one of the most dramatic cardiovascular emergencies. Classically, aortic dissection presents as sudden, severe chest, back, or abdominal pain that is characterised as ripping or tearing in nature. However, a timely diagnosis can be elusive in the event of an atypical presentation. In this report, the authors present two patients with painless aortic dissection who were misdiagnosed during their initial evaluation in the emergency department.     

Acute thoracic aortic dissection: The basics

With an increasing incidence, aortic dissection is the most common acute illness of the aorta. In the setting of chronic hypertension, with or without other risk factors for aortic dissection, this diagnosis should be considered a diagnostic possibility in patients presenting to the emergency department with acute chest or back pain. Left untreated, about 75% of patients with dissections involving the ascending aorta die within 2 weeks of an acute episode. But with successful initial therapy, the 5-year survival rate increases to 75%. Hence, timely recognition of this disease entity coupled with urgent and appropriate management is the key to a successful outcome in a majority of the patients. This article reviews acute thoracic aortic dissection, including ED diagnosis and management.     

Acute Aortic Dissection With ST Segment Myocardial Infarction Following Masturbation

BackgroundAcute aortic dissection is the most common life-threatening disorder affecting the aorta, and can mimic other disease processes. We describe an unusual presentation of a critically ill patient with initial hematospermia diagnosed with a type A acute aortic dissection.Case ReportA 68 year old man presented to a community ED after masturbation and report of blood in his ejaculate, followed by rapid development of severe low back, chest and hip pain with shock. ECG showed evidence of ST segment elevation, but suspicion remained high for thoracic or abdominal aortic catastrophe. Bedside ultrasound demonstrated no pericardial effusion, a severely hypokinetic myocardium and a question of fluid in the left perinephric space. Attempts were made to resuscitate the patient, and an ED chest/abdomen/pelvis CT showed a type A acute thoracic aortic dissection. Unfortunately, the patient remained profoundly unstable, with multiple arrests. He was transferred to a tertiary care facility, but expired shortly after arrival.Why Should an Emergency Physician Be Aware of This?An emergency physician needs to be aware of the myriad of presentations of acute aortic dissection. Although hematospermia was felt ultimately to be an incidental symptom, sexual activity may bring about a significant transient increase in blood pressure, which could contribute to sheer force causing aortic injury. Awareness of this trigger and a careful sensitive history may aid the clinician in early diagnosis.     

Non-traumatic aortic dissection or rupture as cause of cardiac arrest: presentation and outcome

OBJECTIVE: To evaluate the frequency, presentation and outcome of non-traumatic aortic dissection/rupture as a cause of cardiac arrest. DESIGN: Retrospective analysis of a cardiac arrest registry in a tertiary care hospital emergency department. RESULTS: Over 11.5 years, aortic dissection/rupture was identified as the immediate cause of cardiac arrest in 46 (2,3%) out of 1990 patients with sudden cardiac arrest, primarily affecting the abdominal aorta in 25 and the thoracic aorta in 21 cases. The characteristics of the 46 patients were as follows: male gender (74%), median age 71 years (IQR 59-76), high co-morbidity (89%), previously known aortic aneurysm (33%), pulseless electric activity (70%) as initial cardiac rhythm. When performed, bedside abdominal sonography or echocardiography was almost always diagnostic. Patients with abdominal aortic dissection/rupture had abdominal (52%) and/or flank pain (32%). Patients with thoracic aortic dissection/rupture complained of chest pain (48%) or dyspnoea (19%). Return of spontaneous circulation occurred in 12 (26%) of 46 patients, emergency surgery was performed in eight of these patients, 2 (4%) survived to discharge in good neurological condition. CONCLUSIONS: Cardiac arrest caused by aortic dissection/rupture is rare, and mortality remains very high, even when circulation can be restored initially. Common features such as previously known aortic aneurysm, old age, male gender and pulseless electrical activity as initial cardiac rhythm should increase suspicion of the condition.     

Use of three dimensional-printing in the management of floating aortic thrombus due to occult aortic dissection: A case report

BACKGROUNDFloating thrombus within the thoracic aorta is a rare entity but may cause systemic embolism. The pathogenesis of floating aortic thrombi is not yet fully understood. No definitive guidelines are available for the management of floating aortic thrombus.CASE SUMMARYWe report a 48-year-old patient, without a history of trauma and infection, who presented with sudden severe back pain. A floating thrombus within the aortic arch was found by computed tomography angiography (CTA). No evidence of coagulopathies was found. However, with the assistance of a three dimensional-printed model, this floating thrombus was identified to be caused by occult aortic dissection (AD). Subsequently, an emergency thoracic endovascular repair was performed. The patient’s back pain was rapidly alleviated postoperatively. CTA at 1 year showed no filling defect in the stent-graft and aorta.CONCLUSIONOccult AD is a potential factor causing floating aortic thrombi, endovascular stent-graft exclusion may be an optimal therapeutic choice with promising results. Moreover, the combination of CTA and three dimensional-printed models can contribute to the diagnosis and treatment of floating aortic thrombi due to occult AD.