Mobility of the Intimal Flap and Thrombus Formation in Aortic Dissection: A Transesophageal Echocardiographic Study

The mechanisms of the motion of the intimal flap and of thrombus formation in acute or chronic aortic dissection are not definitively elucidated. Transesophageal echocardiography seems to be a technique of choice to analyze the flow in the true and false lumina. Twenty-one consecutive patients were studied in order to define the mobility of the intimal flap, the color Doppler flow patterns, the presence of spontaneous echocardiographic contrast, and thrombus formation at different levels of the aorta. The results suggest that clotted false lumen is more often seen in chronic aortic dissection at the level of the descending thoracic aorta. However, thrombosed false lumen in the aortic arch is suggestive of a retrograde aortic dissection. In cases of complete obliteration of the false lumen, the differentiation between aortic dissection and aortic ectasia with mural thrombus may be extremely difficult.     

Aortic dissection

Aortic dissection is a life-threatening cardiovascular emergency requiring immediate diagnosis and treatment. It is mainly associated with hypertension and the Marfan syndrome. Diagnosis has been revolutionized by the use of transesophageal echocardiography (TEE), which allows for rapid and safe assessment of this condition. Echocardiographic hallmarks of aortic dissection ar the presence of a dissection membrane separating a true from a false lumen, rupture sites in the membrane with to-and-from flow, aortic regurgitation, and pericardial effusion. Dissection of the ascending aorta, which has an extremely high mortality and necessitates emergency surgery, is diagnosed quickly and accurately by TEE.     

Aortic Dissection in Progress Diagnosed by Transthoracic Echocardiography

This report describes a patient who presented with vague chest pain, syncope, and seizures. The diagnosis of dissection of the ascending aorta was clearly established by transthoracic echocardiography. The dissection was initially limited to the ascending aorta. Using the suprasternal window, it was possible to monitor the progression of the dissection almost beat by beat as it extended from the ascending aorta and across the aortic arch to the descending thoracic aorta. Surgical intervention was carried out immediately with successful results. Although transesophageal echocardiography is the procedure of choice in aortic dissection, definitive information can be obtained quickly and safely using the transthoracic approach. The suprasternal window in this case showed the dramatic progression of the disease process.     

Spontaneous echocontrast, recorded by transesophageal echocardiography in type III aortic dissection

Spontaneous echo contrast has been described in cardiac chambers and large vessels during decreased blood flow. We report on a patient with type III aortic dissection and spontaneous echos in the false lumen of the thoracic aorta. Both aortic dissection and spontaneous echos were verified by transesophageal echocardiography but not by transthoracic.     

Echocardiography in the diagnosis of thoracic aortic pathology

Transthoracic two-dimensional and Doppler echocardiography has been well established as a useful technique for evaluating many pathologic processes affecting the thoracic aorta. However, the distance of the aortic arch and descending thoracic aorta from the chest wall and the interposition of highly attenuating lung and highly reflective mediastinal structures between the transducer and the aorta present unavoidable limitations. Transesophageal echocardiography is a relatively new technology that overcomes many of the inherent limitations with transthoracic imaging. Complete echocardiographic evaluation of the entire thoracic aorta can now be achieved in nearly all patients. This article will review the continually expanding role of echocardiography in the evaluation of thoracic aortic pathology, including the dramatic impact of transesophageal imaging on the diagnosis of life-threatening disorders such as aortic dissection.     

Combination of color Doppler and transesophageal echocardiography in emergency diagnosis of type I aortic dissections

We report on the use of colour Doppler- and transesophageal echocardiography in 2 patients with acute type I aortic dissection according to DeBakey. Using transesophageal echocardiography we obtained information on the extension and the entry site of the dissection without interfering with respiration and external thorax configuration. Using colour Doppler we were able to differentiate between the true and false lumen in the thoracic and abdominal aorta due to characteristic phasic flow patterns. In one patient the site of the entry tear of the intimal flap was localized by this method. Furthermore, a noninvasive semiquantitative evaluation of accompanying aortic regurgitation was possible. Colour Doppler gives additional information in the emergency diagnosis of patients with aortic dissection.     

Ambulatory follow-up of aortic dissection by transesophageal two-dimensional and color-coded Doppler echocardiography

Follow-up of 18 patients with aortic dissection (five with type I, one with type II, 11 with type III dissection according to DeBakey) by transesophageal, two-dimensional and color-coded Doppler echocardiography showed a persistence of the false lumen in five of seven patients (71%) after surgery and in nine of 11 patients (82%) after medical therapy. In two patients treated with surgery, the dissected part of the aorta had been resected, whereas in two patients treated medically, a progressive and complete obliteration of the false lumen was observed. In the false lumen, thrombus formation was absent in four, localized in four, and progressive in six patients. Flow within the false lumen could be registered in 14 patients, and two distinct flow patterns were differentiated (laminar biphasic flow or slowly circulating flow). Persisting intimal tears were visualized by two-dimensional echocardiography in four patients, whereas color-coded Doppler showed an additional one to three intimal tears in the descending aorta in 10 patients. Flow across these intimal tears was biphasic in 75% of patients; that is, systolic flow was directed from the true to the false lumen with diastolic flow reversal. Unidirectional flow was detected in 25% of the communications, directed in 20% from the true to the false lumen, serving as an entry only and in one (5%) as reentry only. Additional information concerning complications like extension of the dissection (one of 18 patients), localized dilatation of the regurgitation (three of 18 patients) were detected by this method. Concerning the morphologic findings and the detection of flow characteristics, the transesophageal approach was superior to conventional echocardiography especially in the descending thoracic aorta. Thus, transesophageal two-dimensional and color-coded Doppler echocardiography seems to be an ideal method not only for the easy detection of aortic dissection but also for follow-up.     

主动脉夹层动脉瘤的彩色多普勒超声诊断

目的评价彩色多普勒超声心动图对主动脉夹层动脉瘤（AD）的诊断价值。方法应用彩色多普勒超声心动图对18例疑诊AD的患者进行检查。结果17例经超声检查准确诊断。AD者主动脉均增宽，主动脉壁分离形成真、假两腔，可见内膜片回声；彩色多普勒能直接观察血流由撕裂口进入假腔以及真、假腔内血流变化，并能评价主动脉瓣返流程度。结论彩色多普勒超声心动图能快速、安全、准确地检出本病，对诊断本病具有重要价值。     

Complication of hybrid treatment in type B aortic dissection diagnosed by echocardiography

This case illustrates an unusual and fatal complication after endovascular treatment of type B aortic dissection and highlights the role of echocardiography in the early diagnosis of complications. In this case, a patient with previous diagnosis of chronic type B aortic dissection and moderate aortic regurgitation underwent endovascular repair of the proximal descending aorta and conservative surgical correction of the aortic valve. On early postoperative, a transesophageal echocardiogram and aortic angiotomography demonstrated proximal endoleak by contrast extravasation around the proximal graft attachment site, causing compression of the stent in its middle portion, resulting in narrowing with reduced cross‐sectional area.     

Clinical features of aortic dissection with early thrombosis of the false lumen]

There are cases of dissecting aortic aneurysm in which thrombotic formation occurs in the false lumen at an early stage, preventing dissection of the vessel wall and enlargement of the aneurysm. We studied such early thrombotic obliteration of false lumina in 12 (28.6%) of 42 patients with dissecting aortic aneurysm who underwent transesophageal two-dimensional echocardiography in the acute phase from June 1986 to October 1989. It was the first employment of a transesophageal approach at our hospital. In this study, we examined the clinical profiles of these patients as well as the usefulness of transesophageal two-dimensional echocardiography in establishing the diagnosis of dissecting aortic aneurysm and characterizing the disease. The patients were classified as Type I (2 patients) and Type III (10 patients; 6 Type IIIa and 4 Type IIIb) according to DeBakey's classification. The minimum and mean intervals from the onset of symptoms to transesophageal two-dimensional echocardiography were 1.5 hours and a mean of 38.2 hours, respectively. These results indicated that thrombotic obliteration of the false lumen had already occurred at a very early stage in some patients. The maximum diameter of the descending aorta was mean 37.6 mm with only 2 patients having that of 40 mm or more. Since left intrapleural hemorrhage was observed in these 2 patients (1 received emergent replacement of the descending aorta), enlargement of the aortic diameter may be indicative of unpredictable outcome, even in patients with early thrombotic obliteration of the false lumen. The long-term clinical course was favorable in all patients, including those who were treated surgically, over a mean follow-up period of 14.5 months.(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Usefulness of transesophageal echocardiography in assessment of aortic dissection

BACKGROUND. The value of transesophageal echocardiography in the assessment of patients with aortic dissection was studied. METHODS AND RESULTS. Group 1 (34 patients) represented all patients studied at our institution with this technique in whom aortic dissection was proven by aortography, surgery, or autopsy. Group 2 (27 patients) represented all patients studied with this technique at our institution in whom aortic dissection was excluded by aortography. Transesophageal echocardiography made a correct diagnosis of aortic dissection in 33 of 34 patients (sensitivity, 97%; specificity, 100%). It also correctly demonstrated the type of dissection in all 29 patients with aortographic or surgical proof. On the other hand, computed tomography scanning, performed in 24 of 34 patients in group 1, made a correct diagnosis in only 67% of patients and misclassified the type of dissection in 33%. Transesophageal echocardiography correctly identified involvement of the coronary arteries by aortic dissection in six of seven patients as well as absence of both left and right coronary artery involvement in 10 patients with aortic dissection. This technique was also useful in detecting communications between the true and false lumens, presence of thrombi in the false lumen, and, in two patients, localized dissection rupture with formation of a false aneurysm. In both groups 1 and 2, transesophageal echocardiography correctly identified patients with moderate to severe aortic regurgitation. CONCLUSIONS. Transesophageal echocardiography is very useful in the assessment of aortic dissection.     

Definitive diagnosis of descending thoracic aortic dissection by real time/live three-dimensional transthoracic echocardiography

We describe a patient with descending thoracic aortic dissection in whom three- dimensional transthoracic echocardiography was able to clearly visualize the dissection flap en face as a sheet of tissue, as well as demonstrate a large communication between the true and false lumen in three dimensions, enabling a definitive diagnosis of dissection.     

Color Doppler echocardiography in the diagnosis of aortic dissection and aortic wall abscesses

In eleven patients with aortic dissection or perforated endocarditic aortic wall abscess cavity, the diagnostic usefulness of Color Doppler Echocardiography (CDE) for the identification of true and false lumen as well as the perforation jet was assessed by comparison with the findings of angiography, digital subtraction angiography, computed tomography and surgery. The information gained in addition to that of these procedures, as well as to that of the four conventional echocardiographic techniques was evaluated. Six patients had aortic dissections of DeBakey type I or III; in all of them the diagnosis had been established with conventional ultrasonic techniques. Similarly, in all patients with aortic dissection of DeBakey type I, a clear differentiation between true and false lumen in the aortic root and ascending aorta could already be made by grey-scaled echocardiography. In these patients, however, CDE made the additional demonstration of the perforation jet into the false lumen possible. In those three patients with aortic dissection of DeBakey type III as well as in the abdominal aortic region of DeBakey type I, color Doppler echocardiography was the only method to define true and false lumen and to clearly localize the perforation sites. Two further patients were found to have a small, local dissection, which could only be assumed by conventional echocardiography; the color Doppler M-mode image led to a clear diagnosis. In three patients an endocarditic abscess cavity of the aortic wall could be detected by conventional echocardiography. Two-dimensional color Doppler echocardiography additionally enabled us to visualize the presence and the course of perforation flows. In two patients color-coded Doppler echocardiography made it possible to detect perforations in regions which could not be localized either with conventional echocardiographic techniques or the above-mentioned control procedures.     

Impact of transesophageal color flow Doppler echocardiography in current cardiology practice

Of 3,480 patients who were referred for cardiac ultrasound evaluation, 230 patients (6.6%) underwent transesophageal echocardiography because the transthoracic study was not feasible, technically inadequate, or provided insufficient diagnostic information for optimal patient management. There were 149 inpatients and 81 outpatients. The majority (182 patients, 79%) had aortic or mitral disorders. In 166 patients (72%), transesophageal echocardiography played a significant role in patient management. Transesophageal echocardiography was most useful in evaluating diseases of the aorta (dissection, root abscess, or aneurysm), mitral prosthesis, complications of endocarditis, left atrial appendage thrombi, and in determining the cause of mitral insufficiency. Transesophageal echocardiography was useful in the evaluation of critically ill patients and those with severe lung disease.     

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.     

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.     

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.     

Emergency surgical management of acute aortic dissection: role of transesophageal echocardiography.

The accuracy of transesophageal echocardiography in the diagnosis and surgical management of acute aortic dissection was determined in 54 patients who underwent surgery for acute aortic dissection. Results of the investigations were compared to the surgical assessment. From April 1993 to November 1997, we operated 54 patients (44 male and 10 female) for acute aortic dissection. Mean age was 60 +/- 9 years. At surgery, a De Bakey type I aortic dissection was diagnosed in 30 patients, type II in 23 and type III retrograde in 1. Operating procedures were: replacement of ascending aorta (24 cases), replacement of ascending aorta and aortic arch (17 cases), replacement of ascending aorta and aortic valve replacement (2 cases), Bentall procedure (6 cases) and end-to-end anastomosis of the ascending aorta (4 cases). Initial diagnosis, performed in emergency wards, was done on a clinical basis in 6 patients, on CT scan in 19, on transthoracic echocardiography in 14, and on TEE basis in 12. Three patients underwent angiography before our evaluation. As per our protocol, all patients underwent confirmation of the diagnosis by TEE. Seven patients needed additional instrumental investigations, 2 with CT scan and 5 with angiography. TEE confirmed the diagnosis of aortic dissection in all cases but one. Moreover, it described the site of the intimal tear, the extension of the dissecting process and accessory findings, such as pericardial effusion, aortic incompetence and left ventricular function. The interval between patient presentation and skin incision was a maximum of 70 minutes. At surgery, diagnosis of De Bakey classification was confirmed in 98% of cases; in 90.7% of cases exact location of the entry site was confirmed. In one case, an entry site in the arch diagnosed by TEE but not recognized at surgery, was observed at necropsy. Intraoperatively, we routinely used TEE to monitor retrograde systemic perfusion and correct implant of the vascular prosthesis. One case of malperfusion of the thoracic aorta through the false lumen was observed and managed. In one case we diagnosed acute obstruction of the prosthesis by bleeding in the wrapped aorta, which required reoperation. Assessment of ventricular function was obtained in all patients: in two cases, observation of low right ventricular function led us to perform aortocoronary by-pass to the right coronary artery. In conclusion, the high level of correspondence between TEE diagnosis and surgical anatomy prompted us to perform transesophageal echocardiography as the primary and often sole diagnostic procedure in acute aortic dissection. TEE, in experienced hands, has proven to be a highly reliable, safe and low-cost diagnostic tool. It can be performed at the patient's bedside within just a few minutes of the suspected diagnosis, thereby lowering the mortality rate of the natural history. Again, it can also be used in the operating theatre as an "on-line examination" as well as for assessment of correct surgical repair. Other diagnostic procedures do not yield more information and can cause dangerous delays in intervention.     

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

AIMS: The purposes of this study were to compare the accuracy of multiplane vs. biplane transoesophageal echocardiography (TEE) in the diagnosis of aortic dissection and aortic intramural haematoma, and to test whether these techniques provide all the diagnostic information required to make management decisions. METHODS AND RESULTS: Fifty-eight consecutive patients with clinically suspected aortic dissection were studied with multiplane TEE; all cases who required surgery underwent intraoperative monitoring with multiplane TEE. The following multiplane TEE data were analysed: the angle between current and 0 degrees plane at which each view was obtained; the success rate in the evaluation of true and false lumen, entry tear, coronary artery involvement, aortic regurgitation, pericardial effusion. Advantages of multiplane over biplane TEE have been evaluated by the demonstration of usefulness of views obtained in planes other than 0 degrees-20 degrees or 70 degrees-110 degrees, assuming that with manipulation of a biplane probe a 20 degrees arc could be added to the conventional horizontal and vertical planes. On the basis of TEE findings, aortic dissection was confirmed in 36 cases (18 type A, 12 type B, six intramural haematoma). The specificity and sensitivity of TEE in terms of the presence or absence of aortic dissection or intramural haematoma were 100%. An additional clinical value of multiplane over biplane TEE in the evaluation of ascending aorta, aortic arch, entry tears and coronary artery involvement was demonstrated. All cases with type A aortic dissection or intramural haematoma involving the ascending aorta had an operation that was performed immediately after the diagnosis (hospital mortality, 13%). Patients with type B aortic dissection were treated medically; 25% of these cases were operated later (hospital mortality, 0%). CONCLUSIONS: Multiplane and biplane TEE have excellent and similar accuracies in the evaluation of aortic dissection and intramural haematoma. Multiplane TEE improves the visualization of coronary arteries, aortic arch and entry tears; it appears to be an ideal method as the sole diagnostic approach before surgery in type A aortic dissection.