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.     

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     

Midterm results of aortic diameter outcomes after thoracic stent-graft implantation for aortic dissection: a multicenter study.

PURPOSE: To evaluate aortic diameter outcomes after stent-graft implantation for aortic dissection in the descending thoracic aorta. METHODS: Fifty patients with type A dissection after ascending aortic surgery (n = 10), type B dissection (n = 34), or intramural hematoma (n = 6) underwent stent-graft repair in 3 centers. Thrombosis and aortic diameter were analyzed by computed tomographic angiography at different levels of the aorta before stent-graft implantation, at discharge, and at follow-up. Measurements were standardized. RESULTS: In all, 67 stent-grafts were implanted for acute (n = 18) and chronic (n = 32) dissection. Stent-graft placement was successfully performed with high technical success (100%) despite 4 major complications (iliac thrombosis in 2 cases, aortic rupture, and a type A dissection) in 3 (6%) patients. Complete thrombosis of the thoracic false lumen was observed in 42% and 63% of cases at discharge and at follow-up (mean 15 months), respectively. At follow-up, the diameters of the entire aorta (mean 5 mm, p < 0.05) and the false lumen (mean 11 mm, p < 0.0001) decreased. Diameters of the abdominal aorta remained stable in association with persistent false lumen perfusion at this level. Aortic diameter results were better in the subgroup of patients with intramural hematoma compared to patients with Marfan syndrome. Three early deaths unrelated to the stent-graft procedure occurred; 2 patients with partial thrombosis of the false lumen died in follow-up secondary to aortic diameter growth. CONCLUSION: Complete thrombosis of the false lumen by stent-graft coverage of the entry tear results in decreased diameter of the entire aorta. In patients with partial thrombosis of the false lumen, the aneurysm continues to enlarge.     

Value of echocardiography in patient follow-up after surgically corrected type A aortic dissection.

BACKGROUND: To identify patients (pts) at risk of late complications, follow-up after surgery for type A aortic dissection is essential. We assessed the value of echocardiography to monitor patients after surgery for type A aortic dissection. METHODS: 80 out of 108 pts operated between 1989 and 1999 for type A aortic dissection survived surgery. 62 pts with at least one TEE, CT or MRI examinations during follow-up were included in this study. All pts had transthoracic echocardiography (TTE), 53 transesophageal echocardiography (TEE), 51 had CT, and 39 had MRI. RESULTS: At the first follow-up, 12 of 48 pts with aortic valve sparing surgery presented with aortic insufficiency >I degrees detected using echocardiography. 16 pts evolved a distal aortic aneurysm of over 5 cm, all seen in TEE, CT and MRI. A distal intimal flap was present in 39 pts and could be seen in TEE, CT and MRI in all patients. A new proximal aortic root dissection took place in 5 pts. Progressive aortic pathology led to reoperation in 9 pts. TEE was especially useful in 2 pts to confirm redissection, in 1 pt to rule out redissection assumed by CT, and in 1 with paraprosthetic blood flow after ascending aortic replacement. MRI led to additional information in 1 patient with false aneurysm of the distal anastomosis and 1 with redissection not seen in TEE 6 month before. CT and MRI were superior to TEE in demonstrating aortic arch pathology, whereas TEE was more effective in showing the flow pattern and residual entry sites. CONCLUSIONS: Echocardiography is an effective and cost-saving diagnostic tool to monitor pts after surgery for type A aortic dissection, and should be the method of choice to ascertain aortic pathology initially after surgery. Follow-up intervals and need for additional CT or MRI should be determined afterwards according to specific pathologies.     

Transoesophageal echocardiographic follow-up of patients with surgically treated aortic aneurysms

In the present study, biplane transoesophageal echocardiography(TEE) was scheduled as part of an aneurysm surveillance programmeduring routine ambulatory follow-up of 37 patients followingaortic aneurysm surgery. Time from surgery ranged from 3–72months. Twenty-two patients had had aortic dissection and 15non-dissecting aneurysms. Nineteen patients received an interpositiongraft of the ascending aorta, 12 valved conduit and six an interpositiongraft of the descending thoracic aorta. TEE showed enlargementof the sinus of Valsalva >45 mm in seven patients. Dilatation>45 mm of one or more aortic segments was found in four patients.An intimal flap was present in all patients, with primary aorticdissection if the initial dissection extended beyond the replacedsegment. This was the case in 17 of 22 patients with aorticdissection. One to four intimal tears were identified in 15of these patients. In all patients with intimal tears, flowwas detected by colour flow Doppler in the false lumen. Thrombusformation was nil or minimal in the false lumen in 12 patients. TEE significantly influenced further management in 14 of 37patients (38%). More frequent follow-up was scheduled in eightpatients. Aortic surgery was performed electively for the secondor third time in six patients based on TEE findings. We conclude tliat after surgical repair of aortic aneurysm,the incidence of pathological findings by TEE is high. Thesemay have significant influence on further patient managementand emphasize the need for careful follow-up.     

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.     

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.     

Long-term predictors of descending aorta aneurysmal change in patients with aortic dissection.

OBJECTIVES: We sought to demonstrate the long-term natural course of descending aorta dilation after acute aortic dissection (AD) and identify early predictors for late aneurysmal change. BACKGROUND: Aneurysmal dilation of the aorta is a critical late complication in AD patients. METHODS: Contrast-enhanced computed tomography (CT) was performed during the acute phase in 100 AD patients, comprising 51 type 1 who underwent ascending aorta surgery and 49 type 3 AD patients. Clinical observation was conducted for 53 +/- 26 months, and CT was repeated for 31 +/- 27 months. RESULTS: Aneurysm (diameter > or =60 mm) occurred in 14.4%, 8.2%, 4.1%, and 3.1% of patients at the upper descending thoracic aorta (UT), mid descending thoracic aorta (MT), lower descending thoracic aorta (LT) and abdominal aorta (AA), respectively. Of 53 patients in whom CT was repeated for > or =2 years, the rates of aorta diameter enlargement at the UT, MT, LT, and AA levels were 3.43 +/- 3.66 mm/year, 3.21 +/- 2.70 mm/year, 2.62 +/- 2.19 mm/year, and 1.93 +/- 3.13 mm/year, respectively (p < 0.01), and aneurysm developed in 15 (28%). The initial false lumen diameter at the UT, the aorta diameter at the MT, and Marfan syndrome were independent predictors of late aneurysm. A > or =22-mm initial false lumen diameter at the UT predicted late aneurysm with a sensitivity of 100% and a specificity of 76%. The patients with initial UT false lumen diameter > or =22-mm (n = 42) showed higher event rate (aneurysm or death) than others (n = 58) (p < 0.001). CONCLUSIONS: The UT is the major site of late aneurysmal dilation. A large UT false lumen diameter on the initial CT portends late aneurysm and adverse outcome warranting early intervention.     

Transesophageal Doppler echocardiography in the diagnosis of dissecting aortic aneurysm

Transesophageal Doppler echocardiography (TEDE) was performed in three patients with proven or suspected DeBakey type I and type III aortic dissection. Case 1: A 66-year-old woman, with DeBakey type I aortic dissection. Clear images of a widened dissected aorta and an intimal flap were obtained in both the ascending and descending aorta, including the aortic arch. The site of an entry into the false lumen was identified by the defect of the intimal flap and the pulsatile entry flow through it. The reentry into the true lumen was also identified near the orifice of the celiac trunk. In this case, the observation was performed using this technique during the operation; i.e., replacement of the ascending aorta with an artificial graft. Case 2: A 77-year-old man, DeBakey type III aortic dissection. The study was performed after surgery which consisted of replacement of the descending aorta with an artificial graft. TEDE provided clear images of the artificial graft, the aorta, and their boundaries. The remaining intimal flap was clearly confirmed. Case 3: An 80-year-old man, DeBakey type III aortic dissection. In this case, though abdominal echography suggested aortic dissection, angiography and X-ray CT failed to facilitate the diagnosis. Only TEDE confirmed the diagnosis. The abnormal flow via the entry directing toward the false lumen was clearly demonstrated on the color Doppler images. We therefore conclude that TEDE is a useful and reliable means of diagnosing dissecting aortic aneurysm.     

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.     

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.     

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.     

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.     

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。     

Surgical therapy of thoracic aortic dissection]

Considerable surgical progress of treating aortic dissection has been achieved during the past decade. The emergency indication for acute dissection of the ascending aorta (type A according to the Stanford classification) is unquestioned while surgical treatment for acute dissection of the descending aorta (type B dissection) is mainly reserved for complicated cases. The major complication of acute operations--fatal hemorrhage from the suture line and secondary multi-organ failure--have been successfully reduced by a progress of cardiopulmonary bypass techniques, the introduction of cold cardioplegic myocardial protection, the development of modern suture materials and glues and last not least by a continuous intensive monitoring. Especially the introduction of the so-called french glue safely enabled both the closure of the false lumen as well as the strong reinforcement of the diseased aortic wall and seems to offer a reliable alternative to the application of multi-layered teflon strips. Since the principle of all reconstructive approaches in case of dissection consists of closure of dissected layers and the limited replacement of the segment that is susceptible to a rupture the exact readaptation and reinforcement of the diseased aortic wall represents a fundamental operative step. In type A operations the supracoronary aortic prosthetic replacement or the combined replacement of ascending aorta plus aortic valve followed by the reattachment of coronary arteries has become the standard operative technique. In fact, independently from the location of the primary intimal tear the operation has been traditionally limited to replace the ascending aorta in order to remove an aortic segment that is most likely to rupture. Yet an increasing number of follow-up investigations has demonstrated recurrence of dissection or an aneurysmatical dilatation of the false lumen in about 20% of patients treated with ascending aortic replacement. Consequently, repair of the aortic transverse arch and the radical elimination of the intimal entry is now favoured by an increasing number of surgeons. In addition to these various perioperative and intraoperative adjuncts the introduction of new imaging techniques, especially computerized tomography, magnetic resonance imaging and transesophageal echocardiography allowed to establish adequate therapeutical concepts on a more rational basis. Transesophageal echocardiography as a mobile diagnostic device enables investigators to perform a bed-side dynamic visualization of both the location and extent of a dissection, the evaluation of ventricular performance and aortic competence. Treatment of acute type B dissection is mainly conservative unless complications like intractable pain, aneurysmatic enlargement of the false lumen, ischemia of visceral organs or even rupture occur.(ABSTRACT TRUNCATED AT 400 WORDS)     

The complementary role of magnetic resonance imaging, Doppler echocardiography, and computed tomography in the diagnosis of dissecting thoracic aneurysms

Non-ECG gated MRI was compared with 2DE and/or CT scans in 10 patients with dissecting aneurysms proven by angiography and/or surgery. Patient ages ranged from 48 to 85 years (mean 69.6). Six had DeBakey type I dissections and four had DeBakey type III dissections. MRI was diagnostic for aortic dissection in nine cases and suggestive in the tenth. 2DE was diagnostic in six out of nine patients, suggestive in two patients, and nondiagnostic in one patient. CT was diagnostic in the three cases in which it was employed. MRI demonstrated a dilated ascending aorta with thickened walls in all type I dissections as well as an intimal flap and slow flow in the false channel in four patients. In the other two patients with type I dissection, MRI detected the intimal flap in the descending aorta but not in the ascending aorta, whereas 2DE revealed the ascending aortic intimal flap in both of these patients and CT showed it in one of them. In the type III dissections, MRI demonstrated a thickened wall and thrombus in the lumen in all four cases, and the intimal flap in three out of the four. 2DE excluded ascending aortic involvement in all three type III dissections. Six other patients with fusiform dilated ascending aortas had no evidence of dissection by MRI, 2DE, and aortography. Thus, non-ECG gated MRI alone or in combination with 2DE and/or CT is useful in the diagnosis of dissecting thoracic aneurysm and in assessing the extent of the dissection. In addition, the differentiation of dissecting aneurysms of the aorta from fusiform dilatation of the aorta is made possible by these noninvasive techniques.     

Endovascular stent-graft repair of aortic dissection

Between October 2000 and January 2002, 9 consecutive male patients with subacute or chronic aortic dissection underwent stent-graft placement. The indication for surgery was continuous pain or aneurysm development. One patient had a type A dissecting aortic aneurysm with a primary tear in the ascending thoracic aorta; the other 8 had type B dissection. Placement of an endovascular stent-graft was technically successful in 8 patients, and one underwent an open procedure for abdominal aortic fenestration. The entry site was sealed and the false lumen disappeared in 8 cases, and thrombosis of the false lumen was obtained. Rupture of an iliac artery dissecting aneurysm occurred in one patient 2 days after stent-graft placement; abdominal aortic fenestration with prosthetic replacement of the distal abdominal aorta was performed. One patient died of myocardial infarction 3 days after the stent-graft procedure. During a mean follow-up period of 7 months (1-16 months), one patient died of acute myocardial infarction at 11 months. It was concluded on the basis of these short-term results that endovascular repair of aortic dissection is a promising treatment, and abdominal aortic fenestration is a useful adjuvant procedure.     

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.     

Long-term follow-up after separate replacement of the aortic valve and ascending aorta.

Between May 1974 and November 1991, 28 patients underwent a separate replacement of the aortic valve and the ascending aorta (20 male, eight female; 32 to 71 years old, x = 52 years). 23 patients were operated for ascending aortic aneurysm, three for chronic and two for acute aortic dissection type A. 17/18 patients living at the beginning of this study were re-investigated after a mean follow-up interval of 8.5 years postoperatively with DSA, thoraco-abdominal CT and echocardiography. 1/8 biological aortic valves and 1/20 mechanical valves had to be replaced (four years and two months postoperatively) for valve degeneration and paravalvular leakage respectively. Three patients developed a sinus of Valsalva aneurysm and were reoperated five, 9.2 and 9.3 years after primary repair. In all three patients histological signs of idiopathic degenerative media disease of the aorta were found. Two other patients presented with a perfused perigraft channel and therefore had to be reoperated. Patients with chronic aortic dissection type A and/or ascending aortic aneurysms presenting clinical or intraoperative signs of degenerative media disease of the aorta should undergo composite graft replacement to preclude formation of sinus Valsalva aneurysms.     

Transition from classic aortic dissection to aortic intramural hemorrhage--a case report

A 64-year-old man was hospitalized with chief complaints of chest and back pain. A diagnosis of Stanford type A aortic dissection with a false lumen extending from the ascending to the descending aorta was made based on the results of computed tomography (CT). A CT obtained the following day showed resolution of the false lumen and increased brightness of the aortic wall, typical of aortic dissection with intramural hemorrhage. Although previous studies have described a gradual transition from aortic intramural hemorrhage to aortic dissection with a false lumen, there are no reports of the transition from an aortic dissection with a false lumen to the intramural hemorrhage type of aortic dissection. This patient is of interest when considering the pathogenesis of aortic dissection with intramural hemorrhage and the relationship between the intramural hemorrhage and false-lumen types of aortic dissection.