Penetrating atheromatous ulcer of ascending aorta: a case report and review of literature

Penetrating atherormatous ulcer (PAU) is the condition in which ulceration of an aortic atherosclerotic lesion penetrates the internal elastic lamina into the media. Penetrating atheromatous ulcers usually involve the descending thoracic aorta and are very uncommon in ascending aorta. Differentiation of PAU from other causes of Acute Aortic Syndrome (AAS) such as intramural haematoma (IMH) and aortic dissection is difficult. The diagnosis of these ulcers is made on computerised tomography (CT) scan, magnetic resonance imaging (MRI), or transoesophageal echocardiography (TOE). Once diagnosed, PAU of ascending aorta should be treated surgically on emergency basis. We report on a patient of penetrating atherosclerotic aortic ulcer in ascending aorta with a review of the natural history, imaging diagnosis and management of the condition. She underwent ascending aortic interposition graft using 26mm Dacron graft successfully.     

Penetrating aortic ulcer: Clinical and angiographic characteristics

Penetrating aortic ulcer, an atherosclerotic lesion with ulceration that penetrates the internal elastic lamina and allows hematoma formation within the aortic wall, is rarely considered in the differential diagnosis of patients with sudden onset of severe chest or back pain. It has been suggested that it is a pathologic process that involves elderly hypertensive patients with severe atherosclerosis and rarely has been observed in the ascending aorta. To determine the characteristics of this process, 11 clinical, 2 hemodynamic, 3 angiographic, and 4 surgical variables were compared between 10 consecutive patients with penetrating aortic ulcers and 20 matched patients with classic acute aortic dissection. Clinical and hemodynamic variables were similar in the two compared groups. In the group of patients with penetrating ulcer, mean age was 58±6 years, previous hypertension was observed in six patients and the penetrating ulcer was located in the ascending aorta in six cases. Compared with patients with aortic dissection, more angiographic projections were necessary to obtain the diagnosis in the group of patients with penetrating ulcer (2.4±0.8 vs 1.7±0.6;p<0.05). In addition, the presence of angiographic aortic valve regurgitation was only observed in the group of patients with acute dissection (60% vs 0%;p<0.01). Severe atherosclerosis was not present angiographically in any patient with penetrating ulcer. In conclusion, penetrating aortic ulcer can also affect middle-age patients without severe atherosclerosis and is frequently observed in the ascending aorta. Its form of presentation and clinical characteristics are similar to classic aortic dissection. The lack of confirmatory evidence of dissection with suggestive clinical history should raise the possibility of penetrating aortic ulcer.     

Rapid progression of discrete type A intramural hematoma: prevention of a "procedure-related" complication by intraoperative transesophageal echocardiography.

PURPOSE: To report a case illustrating the utility of transesophageal echocardiography (TEE) before planned stent-graft placement for chronic type B aortic dissection. CASE REPORT: A 64-year-old man with acute aortic syndrome and an 8-year-old interposition graft in the distal aortic arch for acute type B dissection was referred for dissection of the descending thoracic aorta down to the aortic bifurcation; the false lumen was dilated to 65 mm and was partially thrombosed. The ascending aorta showed discrete, eccentric, 4-mm wall thickening that was not considered clinically significant. Stent-graft closure of the entry tear in the proximal descending thoracic aorta was elected. However, as the endovascular procedure was about to commence, TEE showed striking eccentric thickening of the aortic wall of up to 18 mm. The endovascular procedure was stopped, as it was decided to urgently replace the ascending aorta. The next day, the patient underwent successful ascending aortic replacement and simultaneous antegrade stent-graft implantation over the descending thoracic aortic entry tear via the open aortic arch. The postoperative course was uncomplicated, and the patient was discharged 19 days after surgery. He remains well at 6 months after the procedure. CONCLUSIONS: Our case demonstrates that dissection of the ascending aorta may occur not only due to endograft-induced intimal injury, but may also occur due to underlying but undiagnosed or underestimated disease of the ascending aorta or arch. Besides procedural guidance, intraoperative TEE is a useful tool to detect such disease to avoid subsequent "procedure-related" complications.     

Diagnosis of thoracic aortic dissection. Magnetic resonance imaging versus transesophageal echocardiography.

BACKGROUND. Aortic dissection requires prompt and reliable diagnosis to reduce the high mortality. The purpose of this study was to assess the reliability of both ECG-triggered magnetic resonance imaging (MRI) and transesophageal two-dimensional echocardiography combined with color-coded Doppler flow imaging (TEE) for the diagnosis of thoracic aortic dissection and associated epiphenomena. METHODS AND RESULTS. Fifty-three consecutive patients with clinically suspected aortic dissection were subjected to a dual noninvasive imaging protocol in random order; imaging results were compared and validated against the independent morphological "gold standard" of intraoperative findings (n = 27), necropsy (n = 7), and/or contrast angiography (n = 53). No serious side effects were encountered with either imaging method. In contrast to a precursory screening transthoracic echogram, the sensitivities of both MRI and TEE were 100% for detecting a dissection of the thoracic aorta irrespective of its location. The specificity of TEE, however, was lower than the specificity of MRI for a dissection (TEE, 68.2% versus MRI, 100%; p less than 0.005), which resulted mainly from false-positive TEE findings confined to the ascending segment of the aorta (TEE, 78.8% versus MRI, 100%; p less than 0.01). In addition, MRI proved to be more sensitive than TEE in detecting the formation of thrombus in the false lumen of both the aortic arch (p less than 0.01) and the descending segment of the aorta (p less than 0.05). There were no discrepancies between the two imaging techniques in detecting the site of entry to a dissection, aortic regurgitation, or pericardial effusion. CONCLUSIONS. Both MRI and TEE are atraumatic, safe, and highly sensitive methods to identify and classify acute and subacute dissections of the entire thoracic aorta. TEE, however, is associated with lower specificity for lesions in the ascending aorta. These results may still favor TEE as a semi-invasive diagnostic procedure after a precursory screening transthoracic echogram in suspected aortic dissection, but they establish MRI as an excellent method to avoid false-positive findings. Anatomic mapping by MRI may emerge as the most comprehensive approach and morphological standard to guide surgical interventions.     

Comparison of aortic stiffness in patients with juvenile forms of ascending aortic dilatation with versus without Marfan's syndrome

Aortic stiffness in 78 patients with juvenile forms of ascending aortic dilation with Marfan's syndrome was compared with aortic stiffness in 17 patients without Marfan's syndrome. In the ascending aorta and aortic arch, aortic stiffness was similarly increased in the 2 groups. In the descending aorta, however, aortic stiffness was increased only in patients with Marfan's syndrome.     

Intravascular ultrasound in patients with suspected aortic dissection: comparison with transesophageal echocardiography]

Thirteen patients with suspected aortic dissection (two women, 11 men, age 61 +/- 10.8 years) underwent transesophageal echocardiography (TEE), intravascular ultrasound (IVUS), angiography, and in part computed tomography (CT). TEE was performed using 3.5 or 3.75 MHz ultrasound transducers. IVUS examination was done using a 6F 20 MHz "rotational-tip" IVUS catheter (Boston Scientific) advanced over a guiding-wire positioned in the ascending aorta by the "side-saddle" technique. In two patients it was not possible to advance the catheter into the abdominal aorta. Of the remaining 11 patients, eight had aortic dissection (six Typ III, one Typ II, and one Typ I, de Bakey classification). Two patients had aortic aneurysms without dissection and one patient had a perforation of the ascending aorta. TEE, CT, and angiography led to the correct diagnosis in all patients, while IVUS failed to provide precise information within the ascending aorta and the aortic arch. Reasons were the limited scanfield of the 20 MHz transducer and the inability to steer and position the IVUS catheter. Contrary to the limited value in the ascending aorta, IVUS could successfully scan the entire descending aorta, including the dissection membrane and the originating vessels, if the max. diameter was less than 4 cm. No adverse effects occurred. Intravascular ultrasound allows to scan the entire aorta in patients with suspected aortic dissection. The current limitations can be solved only by the introduction of steerable and/or low frequency catheters.     

Echocardiographic Findings Mimicking Type A Aortic Dissection

BACKGROUND: Type A aortic dissection is a rare, but life-threatening disease. The prognosis is determined by an accurate and immediate diagnosis. CASE STUDY: A patient with suspected type A dissection based on outward transesophageal echocardiography (TEE) findings is reported. Renewed TEE showed dilation of the ascending aorta with pronounced wall thickness. A membrane-like structure was found in the ascending aorta. M-mode technique revealed movement of the suspected membrane that was partially in parallel to the aortic wall. Thus, there were severe doubts on the presence of type A dissection. By contrast, typical intimal rupture was found in the descending aorta. Computed tomography (CT) and angiography showed aortic dilation and an extended wall hematoma deriving from the entry at the descending part. There was no evidence of type A dissection. CONCLUSION: TEE is a noninvasive diagnostic tool to assess aortic dissection of type A with a sensitivity of 90-98% that is equal to CT or magnetic resonance imaging (MRI) solely. Complementary use of CT or MRI could improve the diagnostic accuracy. False-positive findings could result from echocardiographic artifacts concealing an intimal flap in the ascending aorta. Echo reverberations in dilated or calcified aortas had been judged to account for this phenomenon. In the present case, it could be assumed that the extended wall hematoma in accordance with vessel dilation mimicked the membrane-like structure. Oscillation or flutter of the suspicious intimal flap independently of aortal wall movement seem to be mandatory to avoid false-positive diagnoses. Ancillary findings such as flow signals, intimal fenestration or thrombosis are helpful to enhance the diagnostic specificity of TEE.     

Assessment of atherosclerotic lesions and distensibility of the thoracic aorta in familial hypercholesterolemia by biplane transesophageal echocardiography]

Atherosclerosis involving the thoracic aorta frequently occurs in patients with familial hypercholesterolemia (FH). In this study, we employed two-dimensional (2-D) transesophageal echocardiography (TEE: 5 MHz) to assess atherosclerotic lesions of the thoracic aorta in 9 patients with FH (47.8 +/- 10.3 yrs) and 11 age-matched normal control subjects. Biplane TEE probe (i.e., transverse or sagittal scan transducer) was used to permit direct imaging of the distal half of the ascending aorta. The atherosclerotic lesions were classified based on the severity of the aortic wall sclerosis as intimal thickening (I.), atheromatous plaque, (II.) and calcification (III.). In all of the patients with FH, atherosclerotic lesions of grade I. or greater were observed particularly in the aortic arch and descending aorta, while, lesions more severe than grade I. in the thoracic aorta were not observed in any of the control subjects. In 6 FH patients (67%), atherosclerotic lesions more severe than grade II. were frequently observed, which were more frequent in the aortic arch and descending aorta than in the ascending aorta.     

Diagnosis of aortic dissection: The value and limitations of transesophageal echocardiography

Aortic dissection requires prompt and reliable diagnosis. The purpose of this study was to assess the accuracy and limitations of transesophageal echocardiography (TEE) for the diagnosis of aortic dissection. Twenty seven patients with clinically suspected aortic dissection were investigated by means of TEE. TEE results were compared to intraoperative findings (n=18), necropsy (n=4), and magnetic resonance imaging (n=5). The DeBakey classification was used for differentiation of dissection type. Twenty-three patients (85%) were correctly identified as having aortic dissection. Four false-positive TEE findings (15%) were confined to the nondissecting aneurysm of the ascending aorta in elderly patients. Retrospectively we found that protruding atherosclerotic plaques were recognized as small intimal flaps. Type of dissection was correctly diagnosed in all 23 patients, the primary entry site was identified in 15 patients (65%), aortic regurgitation was found in 55.5% of patients, and pericardial effusion was detected in 33.3%. We conclude that TEE allows accurate diagnosis and classification of aortic dissection. However, some cases could be overdiagnosed in lesions of the ascending aorta, especially in nondissecting aneurysms. Another limitation of TEE is the inability to define the primary entry site in some cases. Still, overall results may favor TEE as the primary bedside diagnostic procedure to identify patients requiring urgent surgical intervention.Presented at the 35th World Congress, International College of Angiology, Copenhagen, Denmark, July 1993     

Acute aortic syndrome: a case presentation and review of the literature

Aortic disease can present as an acute chest pain syndrome. Although aortic dissection is the most common etiology, other processes such as intramural hematoma (IMH) and penetrating atherosclerotic ulcers are being increasingly recognized. They can all be accurately identified by computed tomography (CT) imaging or transesophageal echocardiography. The overlap between these processes regarding definition and mechanism is controversial. Treatment for all three conditions has thus far been dictated by location, wherein ascending or arch involvement (Stanford type A) necessitates surgery and descending disease (type B) is treated medically. Small studies suggest that subgroups of type A IMH may be treated medically with good outcomes.     

Penetrating atherosclerotic ulcer of the aorta: treatment by endovascular stent-graft placement

PURPOSE OF THE REVIEW: To summarize the current clinical experience with endovascular stent-graft repair in patients presenting with penetrating atherosclerotic ulcer of the descending thoracic aorta. RECENT FINDINGS: Penetrating atherosclerotic ulcer is increasingly acknowledged as a pathologic variant of classic false lumen aortic dissection with a high incidence of bleeding complications and rupture in up to 40% of patients. So far, no generally accepted therapeutic regimen has been established, as the natural history of penetrating atherosclerotic ulcer is not yet fully understood. Recently, however, penetrating atherosclerotic ulcer is increasingly considered to be treated more aggressively (preferentially surgically). Given the high morbidity and mortality of aortic surgery, endovascular stent-graft repair may be an attractive, less invasive alternative in selected patients with penetrating atherosclerotic ulcer. Sealing of a penetrating ulcer by the stent-graft reduces wall stress and thus provides stabilization of the diseased aortic segment. SUMMARY: To date, there is limited experience with endovascular repair in penetrating atherosclerotic ulcer, suggesting that endovascular stent-graft repair is safe and effective. Long-term results are, however, required to fully establish the efficacy of endovascular repair in penetrating atherosclerotic ulcer.     

Long tortuous aorta in a child with Larsen syndrome

A three-year-old boy with unusually flattened facies, multiple joint dislocations and eye abnormalities suggesting the presence of Larsen syndrome presented with a broad mediastinum on routine chest radiography. Computed tomography revealed a huge dilated tortuous aortic arch. Transthoracic echocardiography demonstrated aortic valve dilation, aneurysmal dilation of the ascending aorta with a high aortic arch and a kink in the arch at the isthmus level. Aortography showed a dilated elongated aorta with two acute curves, one at the ductal level and the second at the diaphragmatic level. These aortic lesions may have prognostic significance for the future risk of rupture or dissection. The present article reports the presence of a tortuous aorta in a child with Larsen syndrome.     

Value of transesophageal echocardiography combined with computed tomography for assessing repaired type A aortic dissection.

Thirty-two patients with repaired type A aortic dissection were examined by transthoracic echocardiography (TTE) (n = 32), transesophageal echocardiography (TEE) (n = 30), computed tomography (CT) (n = 29), or a combination of all 3, to assess course and complications as a function of the surgical procedure. The mean follow-up period was 55.7 months (range 3 to 132). Surgery consisted of a replacement of the ascending aorta in 25 patients (group 1) with extension to the transverse aorta in 7 (group 2). The transverse diameter of the aorta, the persistence of the false lumen, thrombus formation and flow dynamics in the false lumen were evaluated by TEE. Ten patients (31%) had a dilation in the initial ascending aorta (sinus of Valsalva aneurysm in 6 patients, and a false aneurysm in the other 4). Three of 4 patients with a proximal pseudoaneurysm underwent operation after TEE and CT evaluation. In the descending thoracic aorta, there was good agreement between TEE and CT scan determinations of transverse vessel diameter. Persistence of flow within the false lumen was significantly more frequent in patients with a dilated aorta (p < 0.05), whereas thrombosis was seen more often and false lumen less often in patients with nondilated aorta. No significant differences in vessel status or outcome were observed between the 2 groups, although this may have been due to the small size of group 2. TEE is thus a well-tolerated method for postoperative follow-up of type A aortic dissection whatever the type of surgery. For the upper ascending aorta, CT provided sufficient data.     

Aortic dimensions in patients with bicuspid aortic valve without significant valve dysfunction

The dimensions of the entire aorta at different anatomic levels were measured by transthoracic 2-dimensional echocardiography in 162 consecutive patients with isolated bicuspid aortic valves (BAVs) without significant aortic valve dysfunction. Aortic dilation involved the aortic root and the ascending aorta but was not present in the descending and abdominal aorta. A significant increase in the dimensions of the aortic arch was found in patients with BAVs aged >40 years. Ascending aortic diameter and the extension of aortic dilation were significantly correlated with age, but no correlation was found between aortic dimensions and aortic valve morphology.     

Acute retrograde dissection of the ascending thoracic aorta.

The clinical, aortographic and pathologic features of six patients with acute retrograde dissection of the ascending thoracic aorta are presented and appropriate guidelines for surgical treatment are proposed. Although acute dissection of the aorta was the clinical diagnosis in these patients, clinical features were not helpful in identifying the pattern or extent of dissection. Aortography demonstrated that the site or sites of intimal tear occurred adjacent to the origin of the innominate artery (three patients) or left subclavian artery (two patients); an intimal tear was not seen in one patient. Five of the six patients also had acute or chronic (or both) antegrade dissection of the descending thoracic aorta. Retrograde dissection of the ascending aorta occurred in the outer portion of the media. The primary histologic changes were fragmentation of elastic fibers and fibrosis of the media. Three patients died, including two of the five patients who were treated surgically; the other three patients survived. Immediate replacement of the ascending aorta with a Dacron graft is recommended to prevent lethal complications due to extension of retrograde dissection, even though dissection may involve both the ascending and descending aorta and the site of intimai disruption may not be resected. The aortic arch or descending thoracic aorta, or both, can be replaced later, utilizing total body hypothermia and temporary circulatory arrest, if further dis-section or enlargement of the aorta occurs after emergency operation on the ascending aorta.     

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.     

胸主动脉病变术中应用经食管超声心动图的初步探讨

目的：探讨胸主动脉疾病的术中应用经食管超声心动图（ＴＥＥ）的价值及适应证。方法：本文报道８例（１５～６３岁，平均年龄４４．５岁）不同类型胸主动脉疾病术中ＴＥＥ监测结果。病例包括先天性主动脉瓣上狭窄、升主动脉瘤、主动脉夹层及主动脉夹层伴假性动脉瘤、胸降主动脉假性动脉瘤、主动脉瓣脱垂等。结果：８例患者的术中检查与术前诊断全部吻合。术中ＴＥＥ发现１例主动脉夹层累及左锁骨下动脉，而术前磁共振成像未能提示。此外，术中ＴＥＥ还显示２例胸降主动脉内的粥样硬化斑块。结论：初步显示术中ＴＥＥ可即刻评价手术效果，对拟行主动脉瓣成形术的患者最有价值；为避免升主动脉粥样斑块的脱落导致术后体循环尤其是脑栓塞，对于高龄患者也积极提倡术中ＴＥＥ监测。     

Detection of dissection of the thoracic aorta: improved specificity by magnetic resonance tomography in comparison with echocardiography techniques]

The purpose of this study was to assess the reliability of conventional transthoracic and transoesophageal two-dimensional echocardiography combined with color-coded Doppler flow imaging (TEE) and ECG-triggered magnetic resonance imaging (MRI) for the diagnosis of thoracic aortic dissection and associated epiphenomena. A total of 53 patients with clinically suspected aortic dissection were subjected to a transthoracic and transoesophageal ultrasound examination and magnetic resonance imaging; the results of each imaging modality were compared and validated against the morphological standards of contrast angiography (n = 53) and/or intraoperative findings (n = 27) or autopsy (n = 7). In this series no deleterious events were encountered with either non-invasive imaging method. In contrast to conventional echocardiography the sensitivities of both MRI and TEE were 100% for detecting a dissection of the thoracic aorta, irrespective of its location. However, the specificity of TEE was lower than the specificity of MRI for a dissection (TEE 68.2% versus MRI 100%; p less than 0.005), which resulted from false positive TEE findings mainly confined to the ascending segment of the aorta (specificity of TEE 78.8% versus 100% by MRI; p less than 0.01). In addition, MRI proved to be more sensitive than TEE in detecting the formation of thrombus in the false lumen of both the aortic arch (p less than 0.01) and the descending segment of the aorta (p less than 0.05). There were no discrepancies between the two imaging techniques in detecting the site of entry to a dissection, aortic regurgitation or pericardial effusion. Both MRI and TEE are atraumatic, safe, and highly sensitive methods to identify and classify acute and subacute dissections of the entire thoracic aorta. However, TEE is associated with lower specificity for lesions in the ascending aorta. These results may still favor TEE after a precursory screening transthoracic echogram in suspected aortic dissection, but will establish MRI as an excellent method to avoid false positive findings. Anatomical mapping by MRI may emerge as a promising comprehensive approach and, eventually, as a morphological standard to guide surgical interventions.     

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.     

Follow-up of patients undergoing surgery for aortic dissection: evaluation with transesophageal echocardiography]

BACKGROUND. Transesophageal echocardiography (TEE) is a useful means in the diagnosis of acute aortic dissection (AD), owing to its very high sensibility and specificity. In this study, TEE was performed to assess post-surgical evolution. PATIENTS. Between 1982 and 1991, 119 pts. were operated on in our institution for AD (De Bakey I and II type): 87 pts. underwent replacement of the ascending aorta with a composite tubular graft bearing a mechanical valve; 26 had a simple tubular graft and 6 had aortic reconstruction. Sixty-eight of 72 discharged pts. were followed for up to 9.5 years (mean 4.5 +/- 2.6). Nine years after surgery actuarial survival of discharged pts. was 75%. Seven pts. died after a mean period of 3.4 years from surgery: only one died from postoperative complication (dehiscence of proximal anastomosis), none for aortic rupture distal to the graft. TEE was performed in 32 of these pts. and in other two operated on elsewhere, after 4.4 +/- 2.7 years from surgery; before the operation, type I AD was diagnosed in 23 pts. and type II in 11 pts. RESULTS. In 10/11 pts. with type II AD the aortic arch and the descending aorta looked normal; in one patient a localized intimal flap was found up to the arch. The descending aorta diameter was somewhat higher than in normal subjects (25.2 +/- 2.8 vs 21.9 +/- 3.7 mm), but in only one case was it beyond 2DS (32 mm). In all type I pts. an intimal flap persisted distal to the graft, along the whole thoracic aorta. Within the false lumen a flow was detected by color-Doppler in 14/23 pts. (61%), and spontaneous echo-contrast was noted in 14 pts. (61%). A thrombus was observed in 7 pts. (30%) and it was generally localized; in only one case it was extensive with total obliteration of the false lumen. In 16 pts. (70%) communications between the two lumina were found. The descending aorta diameter ranged from 25 to 53 mm, and mean value was higher than in normal subjects (34.2 +/- 6.2 vs 21.9 +/- 3.7 mm). CONCLUSIONS. In most pts. with type II AD, surgery can be a definitive treatment, as the remaining aorta keeps to normal size and appearance. In type I AD, operation is only palliative, as the dissection persists: the false lumen is often perfused through one or more communications with the true lumen and seldom its obliteration is noted. The persistence of dissection does not necessarily seem to be an ominous finding, as the survival of the study population was high and no patient died from aortic rupture. Nevertheless, long-term prognosis can be affected by aorta dilation that often (but not always) follows the persistence of wall dissection. For its high reliability, easy feasibility and low cost TEE is a very useful method for following up patients operated on for AD and for detecting those who are at higher risk of aortic rupture because of lumen dilation.