Helical (spiral) CT in the evaluation of emergent thoracic aortic syndromes. Traumatic aortic rupture, aortic aneurysm, aortic dissection, intramural hematoma, and penetrating atherosclerotic ulcer

Trends in aortic dissection hospitalizations, interventions, and outcomes among medicare beneficiaries in the United States, 2000-2011

BACKGROUND

The epidemiology of aortic dissection (AD) has not been well described among older persons in the United States. It is not known whether advancements in AD care over the last decade have been accompanied by changes in outcomes.

METHODS AND RESULTS

The Inpatient Medicare data from 2000 to 2011 were used to determine trends in hospitalization rates for AD. Mortality rates were ascertained through corresponding vital status files. A total of 32 057 initial AD hospitalizations were identified. The overall hospitalization rate for AD remained unchanged at 10 per 100 000 person-years. For 30-day and 1-year mortality associated with AD, the observed rate decreased from 31.8% to 25.4% (difference, 6.4%; 95% confidence interval [CI], 6.2-6.5; adjusted, 6.4%; 95% CI, 5.7-6.9) and from 42.6% to 37.4% (difference, 5.2%; 95% CI, 5.1-5.2; adjusted, 6.2%; 95% CI, 5.3-6.7), respectively. For patients undergoing surgical repair for type A dissections, the observed 30-day mortality decreased from 30.7% to 21.4% (difference, 9.3%; 95% CI, 8.3-10.2; adjusted, 7.3%; 95% CI, 5.8-7.8) and the observed 1-year mortality decreased from 39.9% to 31.6% (difference, 8.3%; 95% CI, 7.5-9.1%; adjusted, 8.2%; 95% CI, 6.7-9.1). The 30-day mortality decreased from 24.9% to 21% (difference, 3.9%; 95% CI, 3.5-4.2; adjusted, 2.9%; 95% CI, 0.7-4.4) and 1-year decreased from 36.4% to 32.5% (difference, 3.9%; 95% CI, 3.3-4.3; adjusted, 3.9%; 95% CI, 2.5-6.3) for surgical repair of type B dissection.

CONCLUSIONS

Although AD hospitalization rates remained stable, improvement in mortality was noted, particularly in patients undergoing surgical repair.

Natural history and outcome of patients with intramural hematomas and penetrating aortic ulcers

All pathologies of acute aortic syndromes should be precisely diagnosed for prompt therapy. Intramural hematomas, as well as penetrating ulcers can be encountered in these patients. Presentations, clinical scenarios, and proper management are outlined in this review, which sums up available current literature to provide the vascular specialist with an adequate understanding of these unique syndromes.

Multidetector-row CT: cardiosurgery indications

This article critically evaluates the role of multidetector-row CT before and after cardiosurgical procedures. In addition, technical aspects, such as scan protocols, optimal image reconstruction intervals, image reformation techniques, and data evaluation, are presented and briefly discussed.

A catastrophic cause of chest pain

Chest pain can be a manifestation of aortic pathology and must be considered in any patient with a history of chest trauma, hypertension, atherosclerosis, connective tissue disorder and/or radiographically abnormal aortic contours. Acute intramural haematoma can resemble acute myocardial infarction and can be life-threatening if not correctly diagnosed. Electrocardiogram (ECG) must be carried out in all patients as it helps distinguish acute myocardial infarction (for which antiplatelets and anticoagulants may be life-saving) from intramural haematoma (for which these drugs may be detrimental). Other imaging modalities may be considered depending upon the clinical situation.

Diagnostic errors in the evaluation of nontraumatic aortic emergencies

Nontraumatic aortic emergencies (NTAE) are a complex and dynamic group of serious, potentially fatal conditions affecting the aorta. These entities most often present in the emergency department setting, and include aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, as well as aortic rupture and impending rupture. The radiologist plays a critical role in prompt diagnosis and evaluation since presenting signs and symptoms are often nonspecific. This article focuses on the potential sources of error in the imaging evaluation of patients presenting with NTAE.

An under Recognized Cause of Chest Pain

Aortic intramural hematoma (IMH) is related to but is pathologically distinct from aortic dissection. In this potentially lethal entity, there is hemorrhage into the aortic media in the absence of an intimal tear. With recent advances in imaging techniques, IMH is now increasingly recognized. The limited data available suggest that the clinical course of IMH mimics that of acute aortic dissection, and mortality rates are similar. Physicians need to be cognizant regarding this entity when they are evaluating chest pain. Here we report a case of IMH, in a 63-year-old female, which was managed conservatively.

MDCT in diagnosing acute aortic syndromes: reviewing common and less common CT findings

Nontraumatic acute thoracic aortic syndromes (AAS) describe a spectrum of life-threatening aortic pathologies with significant implications on diagnosis, therapy and management. In this context, multidetector computed tomography (MDCT) is the gold standard due to its intrinsic diagnostic value; its performance approaches 100% sensitivity and specificity, and it is accepted as a first-line modality for suspected acute aortic disease. MDCT allows early recognition and characterisation of acute aortic syndromes as well as the presence of any associated complications - findings that are essential for optimising treatment and improving clinical outcomes. Although classic CT findings have long been known, other unusual signs are continually reported in the medical literature. We reviewed the classic and less common CT findings, correlating them with pathophysiology, timing and management options, to achieve a definite and timely diagnostic and therapeutic definition.

Superior vena cava obstruction caused by ascending aortic pseudoaneurysm as assessed by multi-detector row computed tomography

We describe a case of a 64-year-old man with superior vena cava (SVC) obstruction caused by a huge pseudoaneurysm of the ascending aorta. Pseudoaneurysm of the ascending aorta is an uncommon cause of SVC obstruction. Multi-detector row computed tomography (MDCT) simultaneously clarified the SVC obstruction and coronary artery stenosis.

Pictorial review: computed tomography features of cardiovascular emergencies and associated imminent decompensation

Multi-detector computed tomography (MDCT) scanner is available in most hospitals and is increasingly being used as the first line imaging in trauma and suspected cardiovascular emergencies, such as acute coronary syndrome, pulmonary artery thrombo-embolism, abdominal aortic aneurysm and acute haemorrhage (Ryan et al. Clin Radiol 60:599-607, 2005). A significant number of these patients are haemodynamically unstable and can rapidly progress into shock and death. Recognition of computed tomography (CT) signs of imminent cardiovascular decompensation will alert the clinical radiologist to the presence of shock. In this review, the imaging findings of cardiovascular emergencies in both acute traumatic and non-traumatic settings with associated signs of imminent decompensation will be described and illustrated.

Intramural haematoma of the thoracic aorta: who's to be alerted the cardiologist or the cardiac surgeon?

This review article is written so as to present the pathophysiology, the symptomatology and the ways of diagnosis and treatment of a rather rare aortic disease called Intra-Mural Haematoma (IMH). Intramural haematoma is a quite uncommon but potentially lethal aortic disease that can strike as a primary occurrence in hypertensive and atherosclerotic patients to whom there is spontaneous bleeding from vasa vasorum into the aortic wall (media) or less frequently, as the evolution of a penetrating atherosclerotic ulcer (PAU). IMH displays a typical of dissection progress, and could be considered as a precursor of classic aortic dissection. IMH enfeebles the aortic wall and may progress to either outward rupture of the aorta or inward disruption of the intima layer, which ultimately results in aortic dissection. Chest and back acute penetrating pain is the most commonly noticed symptom at patients with IMH. Apart from a transesophageal echocardiography (TEE), a tomographic imaging such as a chest computed tomography (CT), a magnetic resonance (MRI) and most lately a multy detector computed tomography (MDCT) can ensure a quick and accurate diagnosis of IMH. Similar to type A and B aortic dissection, surgery is indicated at patients with type-A IMH, as well as at patients with a persistent and/or recurrent pain. For any other patient (with type-B IMH without an incessant pain and/or without complications), medical treatment is suggested, as applied in the case of aortic dissection. The outcome of IMH in ascending aorta (type A) appears favourable after immediate (emergent or urgent) surgical intervention, but according to international bibliography patients with IMH of the descending aorta (type B) show similar mortality rates to those being subjected to conservative medical or surgical treatment. Endovascular surgery and stent-graft placement is currently indicated in type B IMH.

Imaging features of intramural hematoma of the aorta

Intramural hematoma (IMH) is defined as localized hemorrhage within the aortic wall and is included in the acute aortic syndrome spectrum with aortic dissection and penetrating aortic ulcer. The mortality from IMH is similar to classic aortic dissection (21%). 16% of patients with IMH will evolve to classic aortic dissection over time. Despite this confusion exists regarding the precise definitions and radiologic features of IMH versus penetrating ulcers with mural thrombus and overt aortic dissection.

Patent ductus arteriosus masquerading as aortic transection in a trauma victim

A high-speed motorcycle crash is a risk factor for thoracic aortic injury due to the rapid deceleration mechanism. We present a previously healthy 44-year-old man who was involved in a motorcycle accident. Initial spiral computed tomography indicated an intimal flap, which was visualized with evidence of mediastinal hemorrhage. The man was taken emergently to the operating room where a patent ductus arteriosus was seen at the location of the suspected aortic injury. No true aortic injury was appreciated.

Pathophysiology, diagnosis, and management of aortic dissection

Aortic dissection is an uncommon but potentially fatal disease with catastrophic complications. A high level of suspicion is required for successful diagnosis as presenting symptoms are so variable that dissection may be overlooked in up to 39% of cases. It most commonly presents in the elderly population with a history of chronic hypertension. Rapid intervention is necessary as delay leads to higher mortality. Despite advances in diagnostic and therapeutic techniques, morbidity and mortality remains high. Advances in diagnostic imaging have raised the awareness of variants of aortic dissection, including intramural hemorrhage and penetrating aortic ulcer. This distinction is important as the clinical course of these variants differs from that of classical aortic dissection, and thus treatment may also differ. Understanding of these variants has also led to the recognition of markers that may help predict progression to classical aortic dissection and thus warrant closer vigilance in selected patient populations. The recognition that rapid diagnosis is required for management of aortic dissection has led to the investigation of serum tests as diagnostic aids. Serum smooth muscle myosin heavy chain, d-dimer, and serum soluble elastin fragments are promising tests that may help raise suspicion for the diagnosis of acute aortic dissection. The high mortality associated with surgical therapy has led to investigation of alternative approaches. Endovascular therapy has emerged as a viable option in patients with type B dissection who are too unstable for surgery. However, long-term follow up is required to validate this procedure.

Descending Thoracic Aortic Dissection: Evaluation and Management in the Era of Endovascular Technology

Acute aortic dissection is a relatively uncommon but highly lethal condition. Without proper treatment, devastating consequences can occur due to aortic rupture, cardiac tamponade, or irreversible ischemia involving the spinal cord or the visceral organs. The treatment strategy of this condition is in part influenced by the location and the severity of aortic dissection as immediate surgical intervention is necessary in acute ascending aortic dissection, whereas medical therapy is the initial treatment approach in uncomplicated descending aortic dissection. Recent advances of endovascular technology have broadened the potential application of this catheter-based therapy in aortic pathologies, including descending thoracic aortic dissection. In this article, the etiology, pathogenesis, and classification of this condition are discussed. The diagnostic benefits of various imaging modalities for descending aortic dissection are also discussed. Current treatment strategies, including medical, surgical, and catheter-based interventions, are reviewed. Lastly, clinical experiences of endovascular treatment for descending aortic dissection and various endovascular devices potentially applicable for this condition are discussed.

Assessment of aortic pathology and peripheral arterial disease using multidetector computed tomographic angiography

The development of multidetector computed tomography represents a remarkable diagnostic advancement because this imaging modality has been widely used in the evaluation of the cardiovascular system. With scanner-adjusted image acquisition and contrast medium administration, multidetector computed tomographic angiography provides a cost-effective and accurate imaging assessment in patients with aortic pathologies or peripheral arterial occlusive disease. Multidetector computed tomographic angiography is associated with several advantages, including high image spatial resolution and rapid imaging acquisition speed. This diagnostic methodology allows accurate detection of a variety of intravascular lesions in the carotid artery, thoracic and abdominal aorta, renal arteries, and peripheral arterial systems. This article provides an overview of multidetector computed tomographic angiography in the assessment of arterial disease and reviews current literature about this diagnostic technology in the evaluation of aortic and peripheral arterial pathologies.

Descending thoracic aortic dissections

Type B dissection has traditionally been managed medically if uncomplicated and surgically if associated with complications. This practice has resulted in most centers reporting significant morbidity and mortality if open repair is required. In the setting of malperfusion, operative repair has been conjoined with fenestration or visceral stenting to improve outcomes. Endovascular stent grafts seem to offer an attractive alternative in the acute complicated type B dissection, with reduced mortality and morbidity, particularly paralysis, compared with open repair. It is reasonable to consider endovascular stent grafts as another tool in managing dissection, but to recognize that open surgical repair still plays an important role, and that the data that define indications and outcomes are still emerging.

Thoracic aortic endograft collapse after endovascular treatment of a traumatic pseudoaneurysm

Aortic endograft placement is evolving into the standard of care for treatment of patients with anatomically suitable thoracic aortic aneurysms. Application of this technique and these devices in other thoracic aortic pathology, such as traumatic pseudoaneurysms, symptomatic type B aortic dissections, penetrating ulcers, and even mycotic aneurysms, appears to be promising. We report a case in which a stent graft was used to treat a post-traumatic pseudoaneurysm of the thoracic aorta. The case was complicated by delayed collapse of the endograft, which led to hypoperfusion of the extremities, kidneys, and intestines. Reestablishment of endograft patency and distal reperfusion was achieved by placement of two balloon-expandable stents within the endograft. Potential factors leading to the development of this complication are discussed.

Intramural Hematoma and Penetrating Atherosclerotic Ulcer of the Aorta

Intramural hematoma and penetrating aortic ulcer are uncommon but potentially lethal thoracic aortic pathologies. Despite incomplete understanding of their natural history, they have emerged as anatomically appealing targets of endovascular therapy. Appropriate application of these technologies, however, must be predicated on an understanding of the fate of these lesions left untreated, and predictors of their misbehavior. We briefly review the current understanding of these entities.

Anomalous origin of the right coronary artery mimicking aortic dissection at transesophageal echocardiography

Transesophageal echocardiography (TEE) is the most common imaging modality for the detection of acute aortic syndromes. However anomalous anatomic structures may be occasionally misunderstood as pathologic due of lack of familiarity with anatomical variations; false-positive diagnosis can result, potentially leading to unnecessary surgical intervention. It is crucial for echocardiographers to be aware of possible pitfalls which may create false positive findings, since the complementary use of other imaging modalities, such as multislice spiral computed tomography (MSCT), could improve the diagnostic accuracy of TEE. We report a case in which an image resembling an acute aortic dissection (AAD) on transthoracic (TTE) and transesophageal echocardiography was found in a patient with acute chest pain; MSCT detected an anomalous origin of the right coronary artery as cause of false aortic dissection image at echocardiography.

CT Findings of Ruptured Intramural Hematoma of the Aorta Extending Along the Pulmonary Artery

Mediastinal hematoma extending along the pulmonary artery is a rare complication of Stanford type A classic (double-barreled) aortic dissection. Rupture from the posterior aspect of the aortic root penetrates the shared adventitia of the aorta and pulmonary artery. From this location, hematoma can spread along the adventitial planes of the pulmonary arteries out into the lungs. We report a case of ruptured intramural hematoma of the aorta (IMH) extending along the pulmonary artery. To our knowledge, this finding in patients with IMH has not been reported in the literature.

Periaortic lymphoma as a mimic of posttraumatic intramural hematoma

Computed tomography (CT) of an 87-year-old man who presented to the emergency department with chest pain after a motor vehicle collision demonstrated multiple broken ribs and a thoracic periaortic soft tissue mass which was high density on precontrast images and enhanced postcontrast. The scan also demonstrated a mass encircling the left ureter and masses in the axilla and pelvis. The enhancement of the periaortic lesion and the presence of the additional soft tissue masses suggested lymphoma as opposed to intramural hematoma (IMH). The diagnosis of follicular B-cell lymphoma was rapidly confirmed with fluorodeoxyglucose-positron emission tomography/CT and excisional biopsy of the axillary lymph node. While this is an atypical presentation, lymphoma and other extravascular pathology must be considered in the evaluation of a periaortic high attenuation mass seen on CT.

Subtle abdominal aortic injury after blunt chest trauma

This case report describes a patient with an intimal flap of the abdominal aorta after a motor vehicle crash. The patient was an unrestrained driver with minimal anterior chest wall pain. This is a rare injury and one that is difficult to find due to its rarity. The lower cut of the chest CT scan found the injury. Its treatment with endovascular stenting is discussed.

CT Analysis of the Growth Rate of Aortic Diameter Affected by Acute Type B Intramural Hematoma

OBJECTIVE

The purpose of this study was to evaluate the growth rate of aortic diameter affected by acute type B intramural hematoma and the factors that influence its enlargement.

MATERIALS AND METHODS

Fifty-four patients were entered into this study, and regular follow-up CT studies (mean +/- SD, 46.9 +/- 27.2 months; range, 5-136 months) were performed. The affected aortas and iliac arteries were divided into five segments. A total of 127 segments were evaluated (aortic arch, n = 47; descending thoracic aorta, n = 51; suprarenal abdominal aorta, n = 24; infrarenal abdominal aorta, n = 3; and iliac artery, n = 2). The growth rate of each segment was obtained on CT. The factors influencing increase in the diameter and growth rate--age, sex, diabetes mellitus, atherosclerotic disease, history of smoking 20 years, chronic renal failure, blood pressure, initial diameter of the lumen, the presence of blood flow in the false lumen--were evaluated by univariate analysis and a multivariate logistic regression model.

RESULTS

Twenty (37.0%) of 54 patients had one or more segments that increased in size during the follow-up period. Of a total of 127 segments, 35 (27.6%) increased in size, and for all, the mean growth rate was -0.5 +/- 2.9 mm/year. This negative growth rate represents shrinkage. The mean growth rates within the first year and after 1 year from onset were -2.2 +/- 5.7 and 0.4 +/- 3.2 mm/year, respectively, and a significant difference was observed between them (p < 0.0001). An initial diameter of 40 mm or greater and the presence of blood flow in the false lumen were significant risk factors for an increase in the diameter, as confirmed by univariate and multivariate analyses.

CONCLUSION

In patients with type B intramural hematoma, the affected aortas did not show a high incidence of enlargement during the follow-up period, but the affected aortas tended to increase in size after 1 year from onset. An initial diameter of 40 mm or greater and the presence of blood flow in the false lumen were important risk factors for enlargement during the follow-up period.

Nontraumatic Thoracic Emergencies

Acute chest pain is one of the most common complaints of patients who present to an emergency department, and accounts for up to 5% of all visits. It also is one of the most complex issues in an emergency setting because, although clinical signs and symptoms often are nonspecific, rapid diagnosis and therapy are of great importance. The chest radiograph remains an important component of the evaluation of chest pain, and usually is the first examination to be obtained. Nevertheless, cross-sectional imaging has added greatly to the ability to characterize the wide constellation of clinical findings into a distinct etiology. This article reviews how the various entities that can present as nontraumatic chest pain can manifest radiographically.

CT of nontraumatic thoracic aortic emergencies

Computed tomography (CT), especially multidetector row CT (MDCT), is often the preferred imaging test used for evaluation of nontraumatic thoracic aortic abnormalities. Unenhanced images, usually followed by contrast-enhanced arterial imaging, allow for rapid detailed aortic assessment. Understanding the spectrum of acute thoracic aortic conditions which may present similarly (aortic dissection, aneurysm rupture, penetrating atherosclerotic ulcer, intramural hematoma) will ensure that patients are diagnosed and treated appropriately. Familiarity with imaging protocols and potential mimics will prevent confusion of normal anatomy and variants with aortic disease.

Long-term outcome of type B aortic intramural hematoma: comparison with classic aortic dissection treated by the same therapeutic strategy

BACKGROUND

The long-term clinical course and therapeutic strategy of patients with type B aortic intramural hematoma (IMH) are not completely known. The purpose of this study was to clarify long-term prognosis of patients with type B IMH by comparison with type B classic aortic dissection (AD).

METHODS

Clinical data were compared retrospectively between 37 patients with acute type B IMH (IMH group) and 69 patients with acute type B AD (AD group). Our therapeutic strategy for all patients was medical therapy with frequent follow-up imaging studies and timed surgical repair in cases with progression.

RESULTS

Initially, medical therapy was selected for 104 of 106 (98%) patients. In two patients of the AD group, immediate surgical treatment was performed because of aortic rupture. As for complications, no significant difference was seen between the two groups. There was no significant difference in the incidence of the total number of deaths; early death, late death, or causes of deaths. The actuarial survival rates for the IMH group at 1, 2, 5, and 10 years were 97 +/- 3, 97 +/- 3, 85 +/- 9, and 85 +/- 9%, respectively; the values were 96 +/- 1, 96 +/- 1, 89 +/- 4, and 71 +/- 9%, for the AD group. The actuarial survival rates of the two groups were not significantly different from each other (p = 0.398).

CONCLUSIONS

Patients with type B IMH have similar long-term prognosis to patients with type B AD. Medical therapy with frequent follow-up imaging studies and timed surgical repair in cases with progression can be a rational therapeutic strategy in patients with type B IMH.

Transferring Diagnosis Versus Actual Diagnosis at a Center for Thoracic Aortic Disease

BACKGROUND

Lack of physician awareness of thoracic aortic disease has received increased media attention. As a referral center for thoracic aortic disease our institutional experience confirms discrepancies between the transferring diagnosis and the actual pathologic diagnosis. A retrospective review was undertaken to identify the incidence and sources for disparate diagnoses.

METHODS

Medical records from 100 consecutive patients transferred to The University of Florida--Shands Hospital between April 2002 and October 2003 were reviewed. To identify sources for error, the charts of 24 patients with diagnostic discrepancies were examined in detail with attention to outside radiologic reports, level of physician experience, and additional diagnostic testing required.

RESULTS

The transferring diagnosis of 24 patients was different from the final aortic pathologic disease. The most common discrepancies were misclassifications of dissections and aneurysms. Seven patients had either no leak or no dissection. Two patients had misleading "pulsation artifacts" on their computed tomographic scans. In half of the patients diagnostic differences were secondary to initial misinterpretation by the referring radiologist. Seventeen of 24 patients underwent additional diagnostic testing. Misdiagnoses were more common when the referring physician was not a surgeon (15 of 24). The diagnosis of 5 patients was confirmed only in the operating room.

CONCLUSIONS

A significant incidence of disparate diagnosis was identified between transferring facilities and our referral center. Discrepancies were secondary to initial radiographic misinterpretation and the complexity of thoracic aortic pathologic disease. Medical schools and continuing medical education programs should place increased emphasis on thoracic aortic disease in their curricula.

Traumatic Aortic Transection

We report three cases of patients with blunt thoracic trauma, who underwent transesophageal echocardiography (TEE) because of high index of clinical suspicion for acute traumatic aortic syndrome. TEE revealed three different locations of aortic injury one of which was not diagnosed with aortography.