Transesophageal magnetic resonance imaging of the aortic arch and descending thoracic aorta in patients with aortic atherosclerosis

OBJECTIVES

We sought to determine the feasibility and potential of transesophageal magnetic resonance imaging (TEMRI) for quantifying atherosclerotic plaque burden in the aortic arch and descending thoracic aorta in comparison with transesophageal echocardiography (TEE).

BACKGROUND

Improved morphologic assessment of atherosclerotic plaque features in vivo is of interest because of the potential for improved understanding of the pathophysiology of plaque vulnerability to rupture and progression to clinical events. Magnetic resonance imaging (MRI) is well suited for atherosclerotic plaque imaging. Performing MRI using a radio frequency (RF) receiver probe placed near the region of interest improves the signal-to-noise ratio (SNR).

METHODS

High-resolution images of the thoracic aortic wall were obtained by TEMRI in 22 subjects (8 normals, 14 with aortic atherosclerosis). In nine subjects, we compared aortic wall thickness and circumferential extent of atherosclerotic plaque measured by TEMRI versus TEE using a Bland-Altman analysis. Additional studies were performed in a human cadaver with pathology as an independent gold standard for assessment of atherosclerosis.

RESULTS

In clinical and experimental studies, we found similar measurements for aortic plaque thickness but a relative underestimation of circumferential extent of atherosclerosis by TEE (p = 0.001), due in large part to the lower SNR in the near field.

CONCLUSIONS

Using TEMRI allows for quantitative assessment of thoracic aortic atherosclerotic plaque burden. This technique provides good SNR in the near field, which makes it a promising approach for detailed characterization of aortic plaque burden.     

Three-Dimensional Echocardiographic Assessment of Aortic Dissection

In the present study, we report our experience of using three-dimensional reconstruction of transesophageal two-dimensional echocardiographic images in the assessment of aortic dissection (22 patients), aortic rupture (1 patient), aortic aneurysm without dissection (2 patients), and aortic tumor (1 patient).     

Penetrating Atherosclerotic Aortic Ulcer Mimicking Acute Inferior Myocardial Infarction

Penetrating atherosclerotic ulcers (PAU), aortic dissection, and intramural hematoma are the three most important diseases involving the aorta which are classified as acute aortic syndromes. Penetrating atherosclerotic aortic ulceration is characterized by ulceration of atheromatous plaque disrupting the internal elastic lamina. These aortic ulcers may penetrate through the media to cause aortic pseudoaneurysms or less often through the adventitia to cause transmural aortic rupture. We described a case of penetrating atherosclerotic ulcer of ascending aorta mimicking ST elevation myocardial infarction. To our knowledge, this is the first case reported in the literature of such a complication from PAU.     

Aortic coarctation and aneurysms of the ascending aorta

Dissection and rupture of the aorta account for 20% of death in the natural history of aortic coarctation. We describe here in four patients in whom an ascending aortic aneurysm was associated with aortic coarctation. Three patients had aortic valve incompetence. In two cases there was a dissection. This had not been recognized preoperatively in one, in whom the intimal tear was small; in the other patient, with dissection and shock, the associated mild coarctation was demonstrated only at autopsy. Surgical treatment of patients with aortic coarctation and associated aortic aneurysm must include resection of both the stenotic isthmus and dilated section of the aorta, because of a documented poor prognosis. Furtherly, when evaluating patients with aortic dissection a coexisting coarctation although infrequent must be ruled out. If such an association is identified in emergency cases the dissected aorta should be repaired first, employing a suitable technique (double arterial cannulation, above and below the isthmus) in order to ensure adequate perfusion. When there is no acute dissection, repair of the coarctation should be undertaken first.     

Aortic dissection: diagnosis, state-of-the-art of imaging and new management acquisitions.

A prompt diagnosis is the cornerstone of effective treatment of aortic dissection and it is the single most important determinant of survival in this patient population. New imaging modalities such as transesophageal echocardiography, magnetic resonance imaging, helical computed tomography and electron-beam computed tomography have been introduced during the last decade. These new imaging techniques allow for a better and earlier diagnosis of aortic diseases even in emergency situations. Bearing in mind the high overall mortality of aortic dissection, the role of prevention cannot be overstressed. The main risk factor for aortic dissection/rupture is the aortic diameter; therefore we would like to stress the role of aortic replacement as an effective preventive method for aortic dissection/rupture. Determining the right time for elective surgery, when the operative risk is lower than the risk of dilation-related complications, could contribute to a decrease in urgent surgical procedures on the ascending aorta.     

Aorto-right artrial fistula: a rare complication of aortic dissection

We describe the successful surgical repair of an acute aortic dissection that had caused an aorto-right atrial fistula in a 67-year-old man. The patient was admitted to the hospital on an emergency basis because of severe heart failure. The diagnosis of acute aortic dissection with rupture into the right atrium was confirmed by use of intraoperative transesophageal echocardiography, although rupture of a sinus of Valsalva aneurysm into the right atrium had been suggested initially by 2-dimensional and Doppler transthoracic echocardiography. At surgery, we found the patient to have aortic arch dissection with complete separation of the right coronary artery from the sinus of Valsalva and a false lumen that had ruptured into the right atrium. The aortic arch was repaired directly. The ascending aorta was successfully replaced with a composite graft. Aortic dissection with rupture into the right atrium is extremely rare and leads to death rapidly. As shown in this case, such a condition might be mistaken for an aneurysmal rupture of the sinus of Valsalva, with use of transthoracic echocardiography alone. Transesophageal echocardiography is a useful noninvasive method to further define or confirm the diagnosis. Early surgical intervention is necessary in patients with this condition to prevent profound shock and end-organ failure.     

Incremental value of live/real time three-dimensional transesophageal echocardiography over the two-dimensional technique in the assessment of aortic aneurysm and dissection

We compared findings from intraoperative live/real time three-dimensional transesophageal echocardiography (3DTEE) and two-dimensional transesophageal echocardiography (2DTEE) with surgery in 67 patients having aortic aneurysm and/or aortic dissection. Of these, 20 patients had aortic aneurysm without dissection, 21 aortic aneurysm and dissection, and 26 aortic dissection without aneurysm. 3DTEE diagnosed the type and location of aneurysm correctly in all patients unlike 2DTEE, which missed an aneurysm in one case. There were four cases of aortic aneurysm rupture. Three of them were diagnosed by 3DTEE but only one by 2DTEE, and one missed by both techniques. The mouth of saccular aneurysm, site of aortic aneurysm rupture, and communication sites between perfusing and nonperfusing lumens of aortic dissection could be viewed en face only with 3DTEE, enabling comprehensive measurements of their area and dimensions as well as increasing the confidence level of their diagnosis. In all patients with aortic dissection, 3DTEE enabled a more confident diagnosis of dissection because the dissection flap when viewed en face presented as a sheet of tissue rather than a linear echo seen on 2DTEE which can be confused with an artifact. 2DTEE missed dissection in one patient. In six cases the dissection flap involved the right coronary artery orifice by 3DTEE and surgery. These were missed by 2DTEE. Aortic regurgitation severity was more comprehensively assessed by 3DTEE than 2DTEE. Aneurysm size by 3DTEE correlated well with 2DTEE and surgery/computed tomography scan. In conclusion, 3DTEE provides incremental information over 2DTEE in patients with aortic aneurysm and dissection.     

Aortic isthmus stenoses--dilatation in adulthood. A German cooperative study

An analysis of percutaneous transluminal angioplasty of the coarctation of the aorta in adults was evaluated in a cooperative study of the German Working Group of Angioplasty of the German Society of Cardiology. Dilation was performed in 18 patients with a mean age of 26 years (14-49 years). The success rate (gradient less than or equal to 20 mm Hg) was 78% regarding peak to peak gradient, 89% regarding mean gradient. The peak-to-peak gradient decreased from 82 +/- 16 mm Hg to 18 +/- 11 mm Hg. The diameter of the aortic isthmus increased from 0.7 +/- 0.3 cm to 1.3 +/- 0.4 cm (p less than 0.01). After six months only one restenosis occurred. The peak-to-peak gradient measured 10 +/- 12 mm Hg, the diameter 1.4 +/- 0.5 cm. In two patients a balloon rupture occurred without rupture-related complications. No patients died, no cross paralysis or aortic rupture occurred. In three of seven patients with trans-esophageal echocardiographic monitoring a small intimal flap was found; in one patient a media dissection occurred leading to a 15-min period of chest pain and spontaneous healing. In another patient successful dilation was controlled by acute control aortography and computer tomography. After discharge severe chest pain developed. A subtraction angiography of the aorta was negative. Six months later a biplane aortography of the distal thoracic aorta confirmed the diagnosis of aortic dissection type III DeBakey, previously diagnosed by transesophageal echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of Transesophageal Echocardiography for the Assessment of Traumatic Aortic Injuries

Acute traumatic lesions of the thoracic aorta or its branches (TLA) constitute highly lethal yet treatable injuries that are increasingly diagnosed in surviving patients. Traumatic disruptions are limited to the region of the aortic isthmus in ∼ 90% of cases. Unlike aortography, usually referred as the gold standard diagnostic technique, transesophageal echocardiography (TEE) is a noninvasive imaging modality that can be rapidly performed at the patient bedside. Accordingly, TEE is being increasingly used as a first-line screening test for the evaluation of patients with suspected TLA. The TEE signs associated with TLA depend on the anatomic type of aortic disruption. After a period of validation, multiplane TEE allows accurate diagnosis of traumatic disruptions of the aortic isthmus, with a sensitivity of 88% (range, 57%–100%) and a specificity of 96% (range, 84%–100%). False-negative TEE results have been mainly attributed to lacerations of aortic branches. Accordingly, aortography must be routinely performed when a traumatic injury to brachiocephalic arteries is suspected. False-positive TEE findings have been associated with the presence of ultrasound artifacts or atherosclerotic changes that mimic TLA. Accurate determination of the depth of aortic wall tears and diagnosis of blunt cardiac injuries during the TEE study are crucial to guide patient management. The presence of TEE signs associated with imminent risk of adventitial rupture should lead to prompt surgery. The use of TEE as a first-line imaging modality simplifies the initial assessment of patients at high risk for TLA and helps guide acute management.     

Stanford type A aortic dissection in a hypertensive patient with atherosclerosis of aorta and aortitis

Dissection of aorta is a serious condition; the main factors are hypertension and diseases of the connective tissue or of collagen. Aortitis syndrome in combination with hypertension and atherosclerosis in association with ascending aortic dissection is rarely seen. We present the case of a 53-year-old hypertensive patient whose ascending aortic dissection was associated with pericardial effusion without rupture of the aorta and with pleural effusion. Several unusual aspects of transesophageal echocardiography are described. The intraoperative biopsy revealed inflammatory aortitis with mural hematoma, without giant cells. The literature concerning aortic dissection and aortitis is reviewed.     

Correlation between aortic atherosclerosis at transesophageal echocardiography and coronary atherosclerosis

The aim of this study was to test the relationship between atherosclerotic plaques in the thoracic aorta detected by transesophageal echocardiography and coronary artery disease detected by angiography. A prospective study was carried out in 103 patients who underwent coronary angiography. All patients underwent transesophageal echocardiography with imaging of the thoracic aorta. Aortic intimal changes were classified in 4 grades. The detection of aortic atheroma plaques was the strongest predictor of coronary artery disease. The presence of aortic plaques on transesophageal study had a sensitivity of 97.6% and a specificity of 80% for angiographically proved obstructive coronary artery disease. The positive predictive value of aortic plaque for obstructive coronary artery disease was 95.3% and the negative predictive value was 88.9%. Compared to the other segments, the detection of atherosclerotic plaque in the descending aorta has the highest sensitivity but the specificity was the highest in the ascending aorta. With older age and in women the specificity decreased, while the sensitivity increased.     

Intraoperative echocardiography for diagnosis and treatment of aortic dissection. Utility of color flow mapping for surgical decision making in acute stage.

In the past eight years until July 1992, 92 patients were admitted in the acute state of aortic dissection within two weeks from the onset of symptoms. 41 were diagnosed as Stanford type A and 51 were type B by transthoracic and transesophageal echography, computer tomography, and surgery. Sensitivity of transesophageal echography to detect the intimal flap and the false lumen was 97.6% in patients with Stanford type A and 100% in patients with Stanford type B. The surgical decision making has been mostly depending on the transesophageal echographic diagnosis. When the intimal flap was detected in the ascending aorta (Stanford type A) surgery was performed in emergency regardless of any evidence of rupture, cardiac tamponade, and severe aortic regurgitation. When the aortic dissection was detected only in the descending aorta (Stanford type B) the main course of therapeutic strategy in our institute was medical treatment. Surgery was performed on 37 patients of type A and nine patients of type B with mortality of 18.9% and 55.5% respectively. Four patients of type A and 42 patients of type B were treated medically with a mortality of 75.0% and 2.2% respectively. The relatively large leakages from the anastomosis of the aortic clamp site were repaired secondarily in two patients, and fenestration of the superior mesenteric artery was performed on one patient due to ischemia of the small intestine depending on the intraoperative direct scanning of color flow mapping. Coronary artery involvement of dissection was strongly suspected in two patients by intraoperative transesophageal echography and aortocoronary bypass grafting was performed on these patients. Perfusion problems was encountered in five of 37 patients with type A aortic dissection (13.5%) during cardiopulmonary bypass. Intraoperative transesophageal echography could clearly detect the hemodynamic changes in the descending aorta resulting from inadequate perfusion which was useful for the management of perfusion control during cardiopulmonary bypass. Secondary repair of the aortic arch was required due to ischemia of the aortic arch vessels in two patients after the primary surgery. The extension of the dissection into the aortic arch vessels can be promptly diagnosed with the combination of transesophageal echography and transcutaneous echography. In conclusion, transesophageal Doppler echography is the most rapid diagnostic tool for decision making in acute aortic dissection, and intraoperative transesophageal echo can provide useful information to resolve the perfusion difficulties during cardiopulmonary bypass.(ABSTRACT TRUNCATED AT 400 WORDS)     

Quantification of Atherosclerotic Burden in the Descending Aorta by Transesophageal Echocardiography: Inter- and Intraobserver Variability

Atherosclerotic plaques had been imaged but not quantitated in the thoracic aorta using transesophageal echocardiography. The aim of this study was to describe a method for measuring the atherosclerotic plaque area in the descending aorta by transesophageal echocardiography (TEE) and to evaluate its reproducibility. TEE examinations were performed by two independent sonographers, in 21 patients with angiographically proven coronary artery disease. Two hundred fifty-six transverse segments (mean 12 ± 3 patient) of the descending aorta were adequately recorded. In each segment the plaque and the lumen areas in the half of the aortic segment distant from the transesophageal probe were measured by one reader in the two studies (intersonographer reproducibility). Interreader reproducibility was also evaluated. The correlation coefficient between the first and second study (intersonographer reproducibility) was 0.81. The standard deviation of the difference between examinations equaled 0.137 cm² and the mean absolute difference between examinations was 0.003 cm² (95% CI: –0.015; 0.021; P = 0.75). The correlation coefficient between the two readers was 0.86, the standard deviation of the difference between readers was 0.175 cm² and the mean absolute difference was 0.006 cm² (95% CI: –0.029; 0.018; P = 0.63). A method for quantitative measurement of aortic atherosclerotic plaque area was evaluated and found to have high intersonographer and intereader reproducibilities. This method might be used in the future for noninvasive evaluation of regression or progression of aortic atherosclerosis.     

Coronary insufficiency in type II aortic dissection

After coronary sclerosis, aortic dissection represents an important differential diagnosis in the evaluation of acute thoracic pain. We report on a 55-year-old patient with aortic dissection, type II, in whom the diastolic collapse of the true aortic lumen was verified by angiography and transesophageal echocardiography. The collapse led to a temporary perfusion deficit of the left coronary artery with clinical symptoms and ECG changes. Clinical symptoms, additional diagnostic procedures and follow-up of this patient, as well as the value of transesophageal echocardiography, are presented.     

Usefulness of transesophageal echocardiography in the diagnosis of conditions mimicking aortic dissection

Between September 1987 and April 1989, forty patients suspected to have aortic dissection were evaluated by transesophageal echocardiography. Aortic dissection was identified in 18 patients. This study evaluated the ability of transesophageal echocardiography in the assessment of the 22 patients in whom aortic dissection was not found. A range of pathologic conditions was diagnosed in these patients. Five patients had ischemic heart disease when they were initially seen. Among the remaining 17 only one patient had a normal aorta. Aortic disease was present in the other 16 patients with aortic dilatation in 10. Atheromas were detected in seven patients with concomitant aortic dilatation in five of them. An extrinsic aortic mass was present in two patients. Transesophageal echocardiography correctly identified an anastomotic leak at the site of left coronary artery implantation in a patient with a recent Bentall procedure, and a large mobile clot within the proximal descending aorta in a patient with blunt chest trauma. These findings obviated the need for other tests in 15 patients and led to surgery in four with no ancillary tests performed in three of them. Thus transesophageal echocardiography has an important role in assessing patients with suspected dissection. Aortic disease is common even in patients in whom aortic dissection is excluded, and some of the conditions can be just as life-threatening as dissection. Transesophageal echocardiography not only reliably identifies dissection but can also detect luminal and extraluminal diseases not adequately visualized by other modalities.     

Aortic intramural hemorrhage visualized by transesophageal echocardiography: Findings and prognostic implication

Objectives. This study describes the transesophageal echocardiographic and follow-up findings in patients with aortic intramural hemorrhage.Background. Localized aortic intramural hemorrhage resulting in layered thickening of the aortic wall seems to represent a variant of acute aortic dissection without communication or a typical moving intimal flap. In autopsy studies this variant, attributed to a rupture of the van vasorum, has been described in 5% to 10% of patients with dissection.Methods. In a prospective transesophageal echocardiographic study in patients with aortic dissection performed between 1986 and 1991, the diagnosis of intramural hemorrhage was established in 15 of 114 patients and either confirmed anatomically (7 patients) with an additional diagnostic imaging technique or on the basis of clear follow-up changes (8 patients).Results. Elderly patients (mean age 70 years) with a history of hypertension were affected by this variant of dissection. The ascending aorta was involved in 3 patients and the descending aorta in 12. The longitudinal extent varied between 3 and 20 cm, and wall thickness varied between 0.7 and 3 cm. Classic aortic dissection developed in five patients (33%) and rupture in four (27%).Regression of aortic wall thickening was noted in two patients, whereas three patients became asymptomatic without apparent wall changes (33%). Surgery was performed in 5 patients, whereas medical therapy was continued in 10. During a mean follow-up period of 11 months of 11 months, eight patients (53%) died because of complications of the aortic disease.Conclusions. Intramural hemorrhage represents a variant of aortic dissection and may be an early finding in patients who develop classic aortic dissection or rapture. Transesophageal echocardiography is an excellent method for the detection of intramural hemorrhage and for monitoring these patients.     

Three-dimensional transesophageal echocardiographic demonstration of innominate artery dissection

We describe an adult patient with type I aortic dissection in whom it was feasible to demonstrate the extension of the dissection into the innominate artery using color Doppler three-dimensional transesophageal echocardiography.     

Penetrating atherosclerotic aortic ulcer: documentation by transesophageal echocardiography

Objectives. This study sought to describe the ability of transesophageal echocardiography (TEE) to document the presence of penetrating atherosclerotic aortic ulcers and their complications.Background. TEE has greatly enhanced our ability to assess patients with suspected aortic disease. However, the utility of this technique in the diagnosis of penetrating atherosclerotic aortic ulcers is still undefined.Methods. TEE was performed prospectively in 194 patients to evaluate aortic disease. Twelve patients with the diagnosis of aortic ulcers or their complications were specifically studied. The diagnosis was confirmed by pathologic studies in six patients and by an additional diagnostic technique (angiography, computed tomography or magnetic resonance imaging) in the other six. All 12 patients were hypertensive and presented with chest or back pain; the mean age was 65 years (range 56 to 79). The initial working diagnosis was acute aortic dissection in nine patients. Aortic ulcers were located in the descending thoracic aorta in eight patients, the aortic arch in two and the ascending aorta in two.Results. TEE could detect aortic ulcers or their complications in 10 patients but failed to detect these lesions in the remaining 2 (1 with aortic ulcers in the distal ascending aorta and 1 with aortic ulcers in the aortic arch). In four patients, aortic ulcers were detected as a calcified focal outpouching of the aortic wall and were associated with concomitant aneurysmal dilation of the aorta in two patients and with a small localized intramural hematoma in one. TEE visualized a partially thrombosed pseudoaneurysm complicating an aortic ulcer in the descending thoracic aorta of two patients. Four patients had an aortic ulcer complicated by a “limited aortic dissection” in the descending aorta that could be detected by TEE. Five patients underwent operation, two because of aneurysmal dilation of the aorta and three because of aortic dissection; two patients died of aortic rupture; the remaining five did well (11-month follow-up) without operation.Conclusions. Aortic ulcers should be included in the differential diagnosis of chest or back pain, especially in elderly hypertensive patients. These ulcers and their complications may be recognized by TEE.     

Clinical,diagnostic, and management perspectives of aortic dissection

The incidence of aortic dissection ranges from 5 to 30 cases per million people per year, depending on the prevalence of risk factors in the study population. Although the disease is uncommon, its outcome is frequently fatal, and many patients with aortic dissection die before presentation to the hospital or prior to diagnosis. While pain is the most common symptom of aortic dissection, more than one-third of patients may develop a myriad of symptoms secondary to the involvement of the organ systems. Physical findings may be absent or, if present, could be suggestive of a diverse range of other conditions. Keeping a high clinical index of suspicion is mandatory for the accurate and rapid diagnosis of aortic dissection. CT scanning, MRI, and transesophageal echocardiography are all fairly accurate modalities that are used to diagnose aortic dissection, but each is fraught with certain limitations. The choice of the diagnostic modality depends, to a great extent, on the availability and expertise at the given institution. The management of aortic dissection has consisted of aggressive antihypertensive treatment, when associated with systemic hypertension, and surgery. Recently, endovascular stent placement has been used for the treatment of aortic dissection in select patient populations, but the experience is limited. The technique could be an option for patients who are poor surgical candidates, or in whom the risk of complications is gravely high, especially so in the patients with distal dissections. The clinical, diagnostic, and management perspectives on aortic dissection and its variants, aortic intramural hematoma and atherosclerotic aortic ulcer, are reviewed.     

Relationship of hypertensive retinopathy to thoracic aortic atherosclerosis in patients with severe arterial hypertension

Arterial hypertension complicated with atherosclerosis presents the most common cause of death in hypertensive patients. Eyes suffer vascular damage as a result of high blood pressure (BP) and these changes can be detected by funduscopy, although its role has recently been questioned. The aims of this study were to assess the prevalence of atherosclerotic plaques and other disorders of thoracic aorta by transesophageal echocardiography (TEE) in patients with severe arterial hypertension of at least 1 year duration and to analyze the association between aortic atherosclerotic plaques and hypertensive retinopathy. This was a prospective TEE study conducted on 56 hypertensive patients from September 2008 to January 2010. Mean patient age was 62.8 ± 8.2 years and 67.86% of them were women. Aortic atherosclerotic plaques were found on 96.4% of patients, whereas hypertensive retinopathy was present on 94.6% of them. The mean thickness of maximal atherosclerotic plaque found on each patient was 4.3 ± 1.9 mm and 28.6% of patients had ulcerative plaques, while descending aorta was the most common location of the lesions. Grade 1 and 2 hypertensive retinopathy was diagnosed in 14.3% and 80.3% of patients, respectively. Hypertensive retinopathy correlated highly with aortic atherosclerotic score (r = 0.76, p < 0.0001), as it correlated significantly with aortic plaque thickness (r = 0.69, p < 0.0001). Application of funduscopy should be encouraged since it is a noninvasive procedure that provides a good window of retinal arterioles. Hypertensive retinopathy, even in mild forms, should serve as a marker of atherosclerosis elsewhere in the organism.