Evolution of aortic dissection after surgical repair

Patients after aortic dissection repair still have long-term unfavorable prognosis and need careful monitoring. The purpose of this study was to analyze the evolution of aortic dissection after surgical repair in correlation to anatomic changes emerging from systematic magnetic resonance imaging (MRI) follow-up. Between January 1992 and June 1998, 70 patients underwent surgery for type A aortic dissection. Fifty-eight patients were discharged from the hospital (17% operative mortality) and were followed by serial MRI for 12 to 90 months after surgery. In all, 436 postoperative MRI examinations were analyzed. In 13 patients (22.5%) no residual intimal flap was identified, whereas 45 patients (77.5%) presented with distal dissection, with a partial thrombosis of the false lumen in 24. The yearly aortic growth rate was maximum in the descending aortic segment (0.37 +/- 0.43 cm) and was significantly higher in the absence of thrombus in the false lumen (0.56 +/- 0.57 cm) (p <0.05). There were 4 sudden deaths, with documented aortic rupture in 2. Sixteen patients underwent reoperation for expanding aortic diameter. In all but 1 patient, a residual dissection was present (in 13 without any thrombosis of the false lumen). Close MRI follow-up in patients after dissection surgical repair can identify the progression of aortic pathology, providing effective prevention of aortic rupture and timely reoperation. Thrombosis of the false lumen appears to be a protective factor against aortic dilation.     

Expanding false lumen in the abdominal aorta 5 years after endovascular repair of a type B aortic dissection: successful exclusion of 3 distal re-entry sites.

PURPOSE: To report endovascular treatment of an expanding aneurysmal false lumen several years after successful stent-graft deployment in the descending thoracic aorta for type B aortic dissection. CASE REPORT: A 54-year-old woman who had a stent-graft placed at the entry site of a type B aortic dissection 5 years prior presented with abdominal discomfort and palpable abdominal mass. Successful remodeling of the thoracic aorta was demonstrated by computed tomography; however, a false lumen aneurysm in the abdominal aorta had expanded from 4.8 to 6.5 cm and caused symptoms. She was successfully treated with 3 additional stent-grafts at 3 re-entry sites. Six months after the procedure, the false lumen aneurysm was completely excluded. CONCLUSIONS: Endovascular repair of the re-entry sites can prevent further expansion of false lumen aneurysm, which occurs in some patients with type B dissection treated with stent-grafts.     

Postoperative follow-up of type A aortic dissectionexperience with 67 patients]

BACKGROUND: The surgical treatment of type A aortic dissection is usually palliative and most surviving patients remain at considerable risk to develop late postoperative complications; consequently, there is the need for careful long-term follow-up. The present study reports on our experience in the postoperative follow-up of a consecutive series of patients with type A aortic dissection. METHODS: Between January 1986 and December 1996, 89 patients underwent emergency surgery for type A acute aortic dissection; the overall hospital mortality rate was 22% (20/89). This study includes the 69 hospital survivors (49 men and 20 women). Forty-six patients had ascending aortic graft replacement, 13 patients underwent replacement of aortic valve and ascending aorta by a composite graft. The surgical repair was extended to the aortic arch in 5 patients. All patients were serially evaluated by clinical examination and imaging techniques (transthoracic echocardiography in all patients, magnetic resonance imaging in 40, transesophageal echocardiography in 33 and computed tomography in 25). Follow-up was complete in 97% of patients (two patients were lost to follow-up and excluded from the study) and extended to a maximum of 152 months (mean 74 +/- 39 months). The postoperative quality of life was assessed by a questionnaire in 51 current survivors. Risk factors for cardiovascular death, reoperation and poor quality of life were investigated with univariate and multivariate analysis. RESULTS: During the follow-up period 15 patients (22%) died; in 13 cases death was due to cardiovascular causes and in 6 of them it was related to aortic disease. The Kaplan-Meier survival was 92 +/- 3%, 87 +/- 5%, 78 +/- 6% and 70 +/- 8% at 2, 4, 6 and 8 years, respectively. A persistent aortic dissection was demonstrated in 50 patients (75%) and 42 of them showed the presence of flow in the false lumen. A dilatation of one or more aortic segments was found in 59 patients (88%), with a diameter > or = 50 mm in 17 and > or = 60 mm in 8. In 30 patients who underwent transesophageal echocardiography the relation between aortic dimensions and flow pattern in the false lumen was examined; the presence of aneurysmal dilatation with a diameter > or = 50 mm was significantly correlated with a "high flow" pattern. Ten patients (15%) underwent reoperation from 13 to 83 months postoperatively. Reoperation was indicated for: sinus of Valsalva aneurysm and severe aortic regurgitation (2 patients), severe aortic regurgitation (2 patients), aneurysm of the arch (1 patient), thoracoabdominal aneurysm (1 patient), periprosthetic pseudoaneurysm (4 patients). The hospital mortality rate was 20% (2 patients). Sixty-two% of current survivors are asymptomatic; 30 patients returned to their predissection status. Quality of live is judged "good" by 23 patients, "fairly good" by 21 patients and "poor" by 7 patients. No significant independent risk factor for cardiovascular death, reoperation and poor quality of life was identified. CONCLUSIONS: The long-term prognosis after surgical treatment of type A aortic dissection is not satisfactory because of a significant risk of late complications. However, the results of our study can be judged fairly good, particularly if we consider the natural history of the disease.     

False lumen patency as a predictor of late outcome in aortic dissection

Aortic dissection (AD) is a disease with a high-risk of mortality. Late deaths are often related to complications in nonoperated aortic segments. Between 1984 and 1996, we retrospectively analyzed the data of 109 patients with acute AD (81 men and 28 women; average age 61 ± 14 years). All imaging examinations were reviewed, and a magnetic resonance imaging examination was performed at the time of the study. Aortic diameters were measured on each aortic segment. Predictive factors of mortality were determined by Cox’s proportional hazard model, in univariate and multivariate analyses, using BMDP statistical software. Follow-up was an average of 44 ± 46 months (range 24 to 164). Actuarial survival rates were 52%, 46%, and 37% at 1, 5, and 10 years, respectively, for type A AD versus 76%, 72%, and 46% for type B AD. Predictors of late mortality were age >70 years and postoperative false lumen patency of the thoracic descending aorta (RR 3.4, 95% confidence intervals 1.20 to 9.8). Descending aorta diameter was larger when false lumen was patent (31 vs 44 mm; P = 0.02) in type A AD. Furthermore, patency was less frequent in operated type A AD when surgery had been extended to the aortic arch. Thus, patency of descending aorta false lumen is responsible for progressive aortic dilation. In type A AD, open distal repair makes it possible to check the aortic arch and replace it when necessary, decreases the false lumen patency rate, and improves late survival.     

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.     

Provisional extension to induce complete attachment after stent-graft placement in type B aortic dissection: the PETTICOAT concept.

PURPOSE: To report the use of a technique (PETTICOAT: provisional extension to induce complete attachment) to obliterate sustained abdominal false lumen flow and pressurization despite successful stent-graft sealing of the thoracic entry tear in patients with complicated type B aortic dissection. METHODS: Of 100 initial patients subjected to stent-graft repair for complex type B aortic dissection with thoracoabdominal extension, 12 patients (10 men; mean age 58.7 years, range 44-76) demonstrated distal true lumen collapse and a perfused abdominal false lumen despite successful sealing of the proximal tears. As an adjunctive or staged procedure, a scaffolding stent was placed for distal extension of the previously implanted stent-graft. In each case, a Sinus aortic stent, Fortress stent, or a Z-stent system was customized with maximum 2-mm oversizing versus the original stent-graft diameter. Magnetic resonance or computed tomographic angiography was performed at discharge, at 3 months, and then annually to determine false channel thrombosis, true and false lumen dimensions, and re-entry flow. RESULTS: Delivery was successful in all cases (100%). The compressed distal true lumen (mean 4+/-3 mm) was reconstructed to a mean width of 21+/-3 mm, and malperfusion was abolished without any obstruction of the abdominal side branches. At up to 1-year follow-up, there were no signs of expansion or distal progression of the scaffolded dissected aorta. All patients with complete thoracic thrombosis showed evidence of improved aortic remodeling; 1 patient with no false lumen thrombosis died at 11 months from thoracoabdominal aortic rupture. CONCLUSION: The PETTICOAT technique may offer a safe and promising adjunctive endovascular maneuver for patients with distal malapposition of the dissecting membrane and false lumen flow. The technique can both abolish distal true lumen collapse and enhance the remodeling process of the entire dissected aorta.     

Risk factors for descending aortic aneurysm formation in medium-term follow-up of patients with type A aortic dissection

BACKGROUND: After surgery to repair a type A aortic dissection, most late complications and mortality result from descending aorta-related problems. This study was performed to determine the risk factors leading to descending aortic aneurysm formation and late mortality in patients undergoing the type A aortic dissection operation. METHODS: The medical records of patients who survived the operation for type A aortic dissection between 1984 and 1998 were reviewed. There were 144 patients (95 men and 49 women), ranging in age from 24 to 78 years (mean age, 52 years). Most patients were acutely ill, 15 patients were in shock, and 54 patients had cardiac tamponade at the time of the surgical procedure. One hundred thirty-seven patients had ascending aortic replacement only, and of the other 6 patients 2 had hemiarch and 4 had total arch replacement using the elephant trunk technique. The aortic valve was replaced in 23 patients, resuspended in 100, and untouched in 21. Twenty-four risk factors were evaluated in statistical analyses for the prediction of descending aortic aneurysm formation and 3-year mortality. Risk factors were investigated using univariate and multiple logistic regression and survival analyses. RESULTS: The 3-year, 5-year, and 8-year cumulative survival rates were 96.2%, 89.1%, and 80.0%, respectively. The 3-year, 5-year, and 8-year cumulative survival rates, free from descending aortic aneurysm formation or descending aorta operation, were 74.7%, 58.6%, and 43.0%, respectively. Multivariate analysis confirmed that patent false lumen and initial descending aortic diameter were statistically significant risk factors for descending aortic aneurysm formation. CONCLUSIONS: The medium-term survival rate of patients who received operations for type A aortic dissection was satisfactory, despite the high incidence of descending aortic aneurysm formation. The intimal entry site over the aortic arch that was resected during the first operation could decrease the patency rate of a false lumen over the descending aorta. In the absence of a patent false lumen over the descending aorta, the chance of descending aortic aneurysm formation or operation is lessened, and the late survival rate is increased.     

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.     

腔内隔绝术治疗112例Stanford B型主动脉夹层动脉瘤患者疗效观察

目的评价主动脉夹层腔内隔绝术治疗Stanford B型主动脉夹层动脉瘤的院内及长期临床疗效。方法选择行主动脉腔内隔绝术治疗Stanford B型主动脉夹层患者112例。经股动脉切开置入覆膜支架封堵胸主动脉破裂口,置入后冠状动脉造影检查证实疗效,术后随访平均(39±18)个月。分析其临床特点及疗效。结果手术成功112例,共置入覆膜支架119枚。左锁骨下动脉完全被封闭8例,合并严重狭窄病变的冠心病患者完成PCI 16例,主动脉腔内隔绝术后综合征19例,术后1个月内夹层破裂死亡3例。随访3个月,所有患者内膜破裂口封闭,胸降主动脉和腹主动脉真腔扩大,假腔内血栓形成,支架位置、形态正常。术后明显残余内漏10例,3个月自行封闭。术后6个月,再发升主动脉夹层3例,其中行升主动脉外科手术1例,截瘫1例,胃癌多器官转移死亡1例。术后1年迟发性内漏1例。结论腔内隔绝术治疗Stanford B型主动脉夹层动脉瘤的院内及长期疗效满意。     

Restoration of the thoracic aorta in Type A dissection with hybrid prosthesis

Following successful repair of Type A dissection, late morbidity and mortality depend on the progression of residual chronic Type B dissection. To avoid the development of late aneurysms of the descending thoracic aorta, a persistent aortic false lumen around the stent-graft can be prevented by remodeling the thoracic aorta. Ten consecutive patients (mean age: 56 years) with acute Type A dissection underwent a "frozen elephant trunk operation" with the E-vita hybrid prosthesis, under deep hypothermic circulatory arrest, between October 2009 and April 2010. The thoracic aorta was restored to its original size. Computed tomography was used to size the aortic diameter. All patients survived and were routinely discharged. Postoperative computed tomography showed no remaining false lumen and no distal organ ischemia in any patient. No new neurological complication was recorded. Two patients suffered postoperative pulmonary arterial embolism; one underwent embolectomy. Restoration of the thoracic aorta is a safe procedure to close the false lumen during the primary operation for acute Type A dissection. However, the diameter of the stent should reflect the overall aortic size, independent of the diameter of the true lumen.     

Medical vs surgical treatment of acute aortic dissection in an intensive care unit

To determine which therapeutic procedure is most appropriate for which type of aortic dissection, we investigated 146 cases of acute aortic dissection. In the group with dissection of the ascending aorta, 58.6% of patients given medical therapy and 48.8% of patients given surgical therapy died. In the group with dissection of the descending aorta, 14.0% given medical therapy and 50.0% given surgical therapy died. High mortality in the medical group with type A dissection was caused by delayed operation. Better survival was achieved in treated than surgically treated patients with acute distal dissection. In patients with cardiac tamponade, aortic regurgitation, hemothorax/hemo-mediastinum, visceral ischemia and peripheral ischemia, mortalities following medical treatment were fairly high. Surgical treatment brought on improvement in mortality in these groups. However, in the cases complicated by renal dysfunction, the mortality in the surgical group was higher than that in the medical group. 42 patients (28.8%) had no evidence of any complication and only 6 (14.3%) died. In 20 cases (47.6%) of uncomplicated dissection, no blood flow was observed in the false lumen. In cases with open false lumen, the following abnormal findings were more conspicuous: thrombocytopenia, decreased level of fibrinogen, increased fibrin degradation product and soluble fibrin monomer complex. However, these changes seem to be minimal in cases with thrombosed false lumen. The measurement of coagulation factors may be one useful method to determine which therapeutic procedure is most suitable.     

新型三分支主动脉弓覆膜支架在急性Stanford A型主动脉夹层中的应用

目的总结新型三分支主动脉弓覆膜支架治疗急性Stanford A型主动脉夹层的临床应用经验,并评价其安全性和疗效。方法选择2009年12月—2010年10月,在我科接受新型三分支主动脉弓覆膜支架手术治疗地6例急性Stanford A型主动脉夹层患者。结果 6例手术全部成功,无死亡。手术时间（252.4±50.3）min、体外循环时间（133.6±26.1）min、心肌血运阻断时间（82.8±10.9）min、深低温停循环选择性脑灌注时间（17.9±8.1）min。患者术后及时清醒、循环稳定、无严重并发症。6例患者随访3～14个月,主动脉血管成像（CTA）显示患者主动脉弓部及分支动脉内支架扩张贴壁满意、相应部位假腔消失、远端假腔内血栓填充、无与覆膜支架相关的并发症发生。结论采用新型三分支主动脉弓覆膜支架治疗急性Stanford A型主动脉夹层,可以简化主动脉弓部操作步骤、降低手术风险、提高手术成功率,值得临床推广应用。     

DeBakeyⅢ型主动脉夹层21例的临床诊治

目的 探讨主动脉腔内隔绝术（endovascular aortic repair,EVAR）治疗DeBakeyⅢ型主动脉夹层的技术方法及疗效.方法 对近3年江西省人民医收治的21例DeBakeyⅢ型主动脉夹层患者的临床资料进行回顾性分析.19例患者均行左锁骨下动脉穿刺,行升主动脉造影,了解主动脉真假腔、夹层裂口及其与重要血管分支的位置关系.切开右侧股动脉置入覆膜血管内支架,封堵原发破口,置入支架后重复造影检查以观察真假腔血流变化、主动脉分支供血的情况.结果 19例患者支架置入定位准确,术后即刻造影显示真腔血流恢复正常.手术成功率100％,无截瘫及瘤体破裂等严重并发症,无围术期死亡.所有患者术后3～6个月复查增强计算机断层扫描,假腔不再显影,支架通畅,无扭曲、移位.结论 EVAR治疗DeBakeyⅢ型主动脉夹层是安全有效的,但远期效果有待进一步观察.     

Surgical treatment of aortic dissection. Value of echocardiography and MRI for long-term follow-up

Twenty-five patients aged 31 to 74 years (average 50 years) operated for type A aortic dissection (type I: 19 cases, type II: 6 cases) were included in this study. Surgical repair only concerned lesions of the ascending aorta. The hospital mortality was 20 per cent (5 cases), and usually secondary to extension of the dissection. With the exception of 2 late deaths, all patients were followed up for an average of 3.5 years. A late assessment including nuclear magnetic resonance imaging of the thoracic aorta was obtained in 17 of the 18 survivors. These investigations confirmed the good result of repair of the ascending aorta, the uselessness of systematic aortic valve replacement and the palliative nature of repair of type I dissection as 80 per cent of patients had a persistent patent false lumen in the distal aorta.     

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.     

Surgery for three-channeled aortic dissection

Among aortic dissections, three-channeled aortic dissection, in which two parallel false lumens are present, is relatively rare. We surgically treated 26 patients with this type of dissection, they accounted for 7.4% of all 349 patients with aortic dissection surgically treated between 1978 and May 1997. Their ages ranged from 24 to 77 years (mean 45 years). The male/female ratio was 1:1. Marfan's syndrome was present in 15 patients and Bentall's-type operation had been performed in 12 patients. Pain at different times was observed in 19 patients. For preoperative diagnosis, computed tomography (CT) and magnetic resonance imaging (MRI) were useful. The morphology of the 1st and 2nd false lumens was Stanford type A + type B in 11 patients, type B + type B in 12, type A + type A in 2, and localized abdominal dissection in 1. Reentry of the second false lumen was observed in only 3 patients. Descending aortic replacement was performed in 13 patients, thoracoabdominal aortic replacement in 6, ascending aortic replacement in 3, and others in 4. Seven patients died in the hospital. There were 4 late deaths during follow-up for 10–158 months (mean, 58 months). When pain recurred in patients with aortic dissection, three-channeled dissection should be suspected. The incidence of this dissection is high in patients with Marfan's syndrome.Presented at The 39th Annual World Congress International, College of Angiology, Istanbul, Turkey, June 1997.     

分站式杂交手术治疗老年StanfordA型主动脉夹层

目的总结分站式一期杂交手术治疗老年StanfordA型急性主动脉夹层的临床经验及教训,探讨其可行性及适应证。方法2010年4月至2012年1月,广东省人民医院共8例老年（60岁以上）StanfordA型急性主动脉夹层患者接受分站式一期杂交手术治疗。8例患者均正中开胸,在中低温体外循环下以四分支人工血管行“升主动脉置换加主动脉弓去分支技术”。外科手术完成后送介入手术室逆行置入主动脉腔内覆膜支架。观察住院期间康复指标．定期复查全主动脉计算机断层扫描。观察人工血管通畅情况和夹层真假腔情况。结果本组患者无围术期死亡。体外循环时间（70．8_＋13．2）rain;主动脉阻断时间（37．8±6．5）min。患者术后呼吸机使用时间为2~16h,中位时间5h,住重症监护病房时间2—20d,中位时间2d。所有患者全部接受随访,随访时间3～27个月,中位时间13个月,所有患者均生存。术后3个月复查全主动脉增强计算机断层扫描,结果满意。结论分站式一期杂交手术处理老年StanfordA型急性主动脉夹层安全、有效,能明显缩短手术时间、术后呼吸机辅助时间和住院时间．减轻患者的创伤和痛苦,避免深低温停循环的风险,取得满意的近期效果。     

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.     

Prognosis of postoperative aortic dissection. Assessment with magnetic resonance]

OBJECTIVE: To evaluate operated type A aortic dissection by Magnetic Resonance Imaging (MRI), in order to detect long-term complications and identify prognostic indexes of evolution. DESIGN: Prospective study with a three-year period of follow-up. Prognosis evaluation. SETTINGS: Outpatient Clinic at Hospital de Santa Maria and Magnetic Resonance Imaging Center at Hospital da Cruz Vermelha. PATIENTS: A sample of 37 patients submitted to type A aortic dissection surgery, included sequentially, after exclusion of those with contraindication to MRI. METHODS: Initial evaluation (clinical and MRI study) at 3 to 4 months and at 1, 2 and 3 years after surgery. The mean follow-up time was 39.3 +/- 2.9 months. We evaluated the following complications over the aorta (aortic graft and five segments of residual aorta) and the aortic valve: aneurysm, pseudoaneurysm, rupture, re-dissection, progressive aortic valve regurgitation, reoperation and death. The prognostic indexes analysed were: presence of residual flap; false lumen patency; presence of re-entry points; false lumen to aorta dimension ratio; initial aortic dimension; increase of aortic dimension. RESULTS: All patients, with the exception of three that died, remained asymptomatic. COMPLICATIONS: Aneurysm was detected in 45.9% of patients, located in one or more segments; rupture occurred in three patients, preceded by aneurysm and pseudoaneurysm development; moderate or severe aortic regurgitation was detected in 47.8% of patients. Prognostic indexes: 1. Aneurysm development in each segment yeilded a significant association with: presence of residual flap in the same and other segments; higher initial dimension of the same and other segments, with the exception of the abdominal segment; higher increase in dimension of the same and other segments, with the exception of the abdominal segment; 2. Moderate or severe aortic regurgitation development showed a tendency to association with higher increase in dimension of proximal ascending aorta. 3. No association was found between aneurysm and aortic regurgitation development. CONCLUSIONS: Patients operated for type A aortic dissection had a high incidence of late complications which lead to reoperation and in some cases death. The presence of a residual flap, increased aortic dimensions and higher increase rate of aortic dimensions were associated with a complicated evolution. MRI was a very useful technique for long-term monitoring and to identify prognostic indexes of evolution.     

Evaluation of aortic coarctation after surgical repair: role of magnetic resonance imaging and Doppler ultrasound.

OBJECTIVE--To compare the usefulness of magnetic resonance imaging (MRI) and Doppler ultrasound with that of cross sectional echocardiography and oscillometric blood pressure measurement for the evaluation of aortic coarctation after surgical repair. DESIGN--Prospective study. Aortic diameters measured by cross sectional echocardiography, MRI, and angiography (selected cases) and functional data determined by physical examination, oscillometric blood pressure measurement, and continuous wave Doppler. SETTING--Tertiary referral centre. PATIENTS--40 patients aged 2-28 years (mean 10.6 years) who had had surgical correction of aortic coarctation (mean follow up 5.7 years). RESULTS--In all patients MRI gave diameter measurements of the aortic arch and the thoracic aorta whereas in half of them cross sectional echocardiographic measurement of the isthmic region failed. The correlation coefficient for aortic diameters measured by MRI and angiography was 0.97 and that between MRI and echocardiography was 0.89. Peak velocities in the descending aorta correlated better with residual narrowing of the aortic isthmus or distal aortic arch or both than systolic blood pressure gradients between the upper and lower limbs. A peak velocity of < 2 m/s in the descending aorta during systole excluded important restenosis. Prolongation of anterograde blood flow during diastole always indicated a morphological abnormality--either important restenosis or aneurysmal dilatation. CONCLUSIONS--MRI was better than cross sectional echocardiography for imaging the aortic arch after coarctation repair and measuring its diameter. Peak velocity in the descending aorta correlated better with residual stenosis than did the systolic blood pressure gradient between the upper and lower limbs and this index could be used to indicate a need for MRI.