Acute dissecting aneurysms of the aorta: diagnosis and treatment--1979

Clinical Characteristics and Risk Factors of Noninfectious Fever after Thoracic Endovascular Aortic Repair of Acute Type B Aortic Dissection

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) is gradually becoming a first-line treatment of complicated acute type B aortic dissection (ATBAD). Interestingly, according to years of experience in the treatment of ATBAD, we found that patients with ATBAD often had unexplained noninfectious fever after TEVAR. This study aims to explore its clinical characteristics and independent risk factors.

METHODS

From January 2016 to September 2021, 211 consecutive patients treated electively by TEVAR for ATBAD were included. The entry tears in all patients originated in the distal to the left subclavian artery (LSA). All patients were diagnosed with ATBAD for the first time. The definition of fever in this study was that the body temperature of patients after TEVAR exceeds 38°C.

RESULTS

A total of 211 patients (53.62 ± 11.34 years, 81% men) were included in the analysis. To compare patients who did and did not have post-TEVAR fever, they were respectively classified as the fever group and the nonfever group. Fever was diagnosed in 115 (55%) patients. Preoperatively, statistical differences were recorded in age (P = 0.023) and red blood cell (P = 0.037). Age <60 years [odds ratio (OR) 2.194, 95% confidence interval (CI) 1.147-4.196, P = 0.018] and duration of the operation >3 hr (OR 3.586, 95% CI 1.133-11.350, P = 0.03) were positively associated with fever. In the comparison of preoperative and postoperative experimental data, the changes in white blood cell (P = 0.046) and platelet (P = 0.007) of the 2 groups were significantly different. Hospital stay (P = 0.009) and postoperative hospital stay (P < 0.001) in the fever group were significantly prolonged. There was no difference in survival in the mid- and long-term follow-up between the 2 groups.

CONCLUSIONS

Noninfectious fever occurs in more than half of the patients after TEVAR (115/211, 54.5%). Patients in the fever group are younger. Age <60 years and duration of the operation >3 hr are independent risk factors for noninfectious fever in patients with ATBAD after TEVAR fever. Noninfectious fever after TEVAR may lead to prolonged hospital stay. However, it did not affect mid- and long-term prognosis.

Acute aortic dissections with entry tear in the arch: A report from the International Registry of Acute Aortic Dissection

OBJECTIVE

To analyze presentation, management, and outcomes of acute aortic dissections with proximal entry tear in the arch.

METHODS

Patients enrolled in the International Registry of Acute Aortic Dissection and entry tear in the arch were classified into 2 groups: arch A (retrograde extension into the ascending aorta with or without antegrade extension) and arch B (only antegrade extension into the descending aorta or further distally). Presentation, management, and in-hospital outcomes of the 2 groups were compared.

RESULTS

The arch A (n = 228) and arch B (n = 140) groups were similar concerning the presence of any preoperative complication (68.4% vs 60.0%; P = .115), but the types of complication were different. Arch A presented more commonly with shock, neurologic complications, cardiac tamponade, and grade 3 or 4 aortic valve insufficiency and less frequently with refractory hypertension, visceral ischemia, extension of dissection, and aortic rupture. Management for both groups were open surgery (77.6% vs 18.6%; P < .001), endovascular treatment (3.5% vs 25.0%; P < .001), and medical management (16.2% vs 51.4%; P < .001). Overall in-hospital mortality was similar (16.7% vs 19.3%; P = .574), but mortality tended to be lower in the arch A group after open surgery (15.3% vs 30.8%; P = .090), and higher after endovascular (25.0% vs 14.3%; P = .597) or medical treatment (24.3% vs 13.9%; P = .191), although the differences were not significant.

CONCLUSIONS

Acute aortic dissection patients with primary entry tear in the arch are currently managed by a patient-specific approach. In choosing the management type of these patients, it may be advisable to stratify them based on retrograde or only antegrade extension of the dissection.

Spontaneous Resolution of a Descending Aortic Dissection

The natural history of an aortic dissection is either endothelialization of the false lumen forming a so-called double-barrelled aorta, or thrombosis of the sack leading to fibrosis and scarring. Complete healing of an aortic dissection is extremely rare, and has to our knowledge only been reported once in vivo. Here we report a second case of spontaneous resolution of an aortic dissection, disclosed by contrast medium enhanced computed tomography.

Natural history and outcome of patients with intramural hematomas and penetrating aortic ulcers

All pathologies of acute aortic syndromes should be precisely diagnosed for prompt therapy. Intramural hematomas, as well as penetrating ulcers can be encountered in these patients. Presentations, clinical scenarios, and proper management are outlined in this review, which sums up available current literature to provide the vascular specialist with an adequate understanding of these unique syndromes.

Use of a stent-graft and vascular occlude to treat primary and re-entry tears in a patient with a Stanford type B aortic dissection

Thoracic endovascular aortic repair for aortic dissections is recognized as an effective treatment. We herein report the case of a 72-year-old male with a Stanford type B aortic dissection. A stent-graft and double-disk vascular occluder was used to repair the primary and re-entry tears, respectively. At 3 month postoperatively, computed tomographic angiography revealed no endoleaks, the stent-graft and vascular occluder to be in optimal positions, the false lumen was almost completely thrombosed, and the visceral arteries were patent. This case illustrates that it is feasible to treat re-entry tears with a vascular occluder after primary proximal stent-graft repairs.

Preliminary report on a sonographic method to determine the location of the intimal breach in Stanford type B aortic dissection

Using a defined angle T, which can be measured noninvasively using Doppler ultrasound, we aim to determine the location of the intimal breach in Stanford type B aortic dissection (AD) and estimate the risk of AD using that measurement. Our subjects included 86 healthy volunteers, 60 hypertensive patients, and 42 patients with Stanford type B AD. We used dual functional color Doppler ultrasound to locate the central point of the high-speed flow zone within the descending aorta, and then calculated the angle T, using the law of cosines. In addition, we measured the degree of distortion within the descending aorta using Line BD, defined as the distance from the lateral edge of the left subclavian artery (LSA) to the center of the breach in the intima in AD. The value of T was approximately 24° ± 3° and was constant across all 3 groups. In addition, the increase in BD distance corresponded to increased distortion in the descending aorta between the LSA and the region of aortic artery ligament (RAALE). We found that when the preoperative BD was less than 2.6 cm, the aortic arch could be straightened, using a stent-graft, to approximate the normal aorta. When the preoperative BD is less than 2.6 cm, the aortic arch can be corrected using a stent. In addition, since the T angle is constant, we speculate that it can be used to predict the risk of intimal breach and estimate its location using digital subtraction angiography (DSA) to guide surgery.

Multidetector CT of Aortic Dissection: A Pictorial Review

Aortic dissection is the most common acute emergency condition of the aorta and often has a fatal outcome. Outcome is determined by the type and extent of dissection and the presence of associated complications (eg, cerebral sequelae, aortic branch involvement, pericardial involvement, and visceral involvement), with early diagnosis and treatment being essential for improved prognosis. Aortic dissections are classified on the basis of the site of the intimal tear according to the Stanford classification system. Type A aortic dissection involves the ascending thoracic aorta and may extend into the descending aorta, whereas in a type B dissection the intimal tear is located distal to the left subclavian artery. Type A dissection typically requires urgent surgical intervention, whereas type B dissection can often be treated medically. Modern multidetector computed tomography (CT) is a fast, widely available imaging modality with high sensitivity and specificity. Multidetector CT allows the early recognition and characterization of aortic dissection as well as determination of the presence of any associated complications, findings that are essential for optimizing treatment and improving clinical outcomes.

Diagnosis and management of acute aortic dissection, clinical and radiological follow-up

A clinical series of acute aortic dissections is presented. Twenty cases were of type A and 10 of type B. Acute severe chest pain was common, in type A also blood pressure difference between the arms and aortic regurgitation. The diagnosis was established by echocardiography, computerized tomography and/or aortography. Antihypertensive therapy was instituted immediately after diagnosis and was in type A cases followed by acute surgery unless definite contraindications existed. Of 14 surgically treated type A patients 13 survived the operation. On follow-up 1.5-3.5 years later, 12 patients were still alive and doing well, but the false channel remained open in all cases where it had not been resected totally. Only one of six conservatively treated type A patients survived. Type B dissections were operated on only if conservative therapy failed. Four of five conservatively and two of five surgically treated type B patients survived.

Pathophysiology, diagnosis, and management of aortic dissection

Aortic dissection is an uncommon but potentially fatal disease with catastrophic complications. A high level of suspicion is required for successful diagnosis as presenting symptoms are so variable that dissection may be overlooked in up to 39% of cases. It most commonly presents in the elderly population with a history of chronic hypertension. Rapid intervention is necessary as delay leads to higher mortality. Despite advances in diagnostic and therapeutic techniques, morbidity and mortality remains high. Advances in diagnostic imaging have raised the awareness of variants of aortic dissection, including intramural hemorrhage and penetrating aortic ulcer. This distinction is important as the clinical course of these variants differs from that of classical aortic dissection, and thus treatment may also differ. Understanding of these variants has also led to the recognition of markers that may help predict progression to classical aortic dissection and thus warrant closer vigilance in selected patient populations. The recognition that rapid diagnosis is required for management of aortic dissection has led to the investigation of serum tests as diagnostic aids. Serum smooth muscle myosin heavy chain, d-dimer, and serum soluble elastin fragments are promising tests that may help raise suspicion for the diagnosis of acute aortic dissection. The high mortality associated with surgical therapy has led to investigation of alternative approaches. Endovascular therapy has emerged as a viable option in patients with type B dissection who are too unstable for surgery. However, long-term follow up is required to validate this procedure.

Prognosis for Patients With Type B Acute Aortic Dissection Risk Analysis of Early Death and Requirement for Elective Surgery

BACKGROUND

The long-term outcome of medical treatment in patients with type B acute aortic dissection (BAD) was assessed and predictors of early in-hospital death were investigated, as well as the need for surgical intervention.

METHODS AND RESULTS

In the past 11 years, 180 patients were admitted to hospital and medically treated at the time of onset. If the maximum diameter of the dissected aorta exceeded 60 mm, or rapid enlargement or vital organ ischemia were identified, early or elective surgery was performed. Emergency operation was required in 7 patients. Elective surgery was required for 31 patients (19.1%). The operation-free rate was 76.0% at 10 years. Actuarial survival rate was 89.4% at 5 years and 71.8% at 10 years. Multivariate analysis indicated that refractory hypertension (odds ratio (OR), 4.08, 95% confidence interval (CI), 3.06-21.44, p=0.0434) and rupture (OR 5.87, 95% CI, 2.21-9.12, p=0.0154) were predictors of early hospital mortality. The only significant predictor for elective surgery was a maximum diameter exceeding 40 mm at the time of onset (OR 13.4, 95% CI, 1.93-6.89, p=0.0003).

CONCLUSIONS

Medical treatment for BAD produced good results. Strict control of blood pressure is important for patients with a dissected aortic diameter exceeding 40 mm at the time of onset.

[Long-term MRI follow-up of aortic dissection in 56 patients: therapeutic impact]

PURPOSE

To retrospectively assess the value of MRI in long-term follow-up of aortic dissection (AD) and its impact on therapy.

MATERIALS AND METHODS

Comparison of clinical progression and analysis of 215 MRI examinations performed on 56 patients in our center from 1991 to 2002.

RESULTS

Twenty-six patients (46%) had AD complications: 14 (54%) were asymptomatic and eight (31%) had subsequent surgical repair (native aorta upstream prosthesis disease in three patients and aneurismal dilatation of false lumen in five cases). Of the eight patients with secondary surgery, five (63%) were clinically asymptomatic. The delay between initial dissection and secondary surgery was less than 5 years in five patients and exceeded 10 years in three cases. The remaining 30 patients (54%) had unmodified radiological findings after a mean follow-up of 3.5 years (6 months to 9 years).

CONCLUSION

MRI depicted AD complications in long-term follow-up of sometimes asymptomatic patients, allowing for adaptation of surgical treatment in 26 cases (46%).

Role and results of surgery in acute type B aortic dissection: insights from the International Registry of Acute Aortic Dissection (IRAD)

BACKGROUND

The clinical profiles and outcomes of patients treated surgically for acute type B aortic dissection (ABAD) are often reported for those in small series or for those cared for at a single institution over a long time period, during which a continuous evolution in techniques has occurred. Accordingly, we sought to evaluate the clinical features and surgical results of patients enrolled in the International Registry of Acute Aortic Dissection by identifying primary factors that influenced surgical outcome and estimating average surgical mortality for ABAD in the current era.

METHODS AND RESULTS

A comprehensive analysis of 290 clinical variables and their relation to surgical outcomes for 82 patients who required surgery for ABAD (from a population of 1256 patients; mean+/-SD age, 60.6+/-15.0 years; 82.9% male) and who were enrolled in the International Registry of Acute Aortic Dissection was performed. The overall in-hospital mortality was 29.3%. Factors associated with increased surgical mortality based on univariate analysis were preoperative coma or altered consciousness, partial thrombosis of the false lumen, evidence of periaortic hematoma on diagnostic imaging, descending aortic diameter >6 cm, right ventricle dysfunction at surgery, and shorter time from the onset of symptoms to surgery. Factors associated with favorable outcomes included radiating pain, normotension at surgery (systolic blood pressure 100 to 149 mm Hg), and reduced hypothermic circulatory arrest time. The 2 independent predictors of surgical mortality were age >70 years (odds ratio, 4.32; 95% confidence interval, 1.30 to 14.34) and preoperative shock/hypotension (odds ratio, 6.05; 95% confidence interval, 1.12 to 32.49).

CONCLUSIONS

The present study provides insights into current-day clinical profiles and surgical outcomes of ABAD. Knowledge about different preoperative clinical conditions may help surgeons in making treatment decisions among these high-risk patients.

The effect of beta-blocker therapy on clinical outcome in patients with Marfan's syndrome: a meta-analysis

OBJECTIVE

To assess the effect of beta-blockade therapy on clinical outcome in patients with Marfan's syndrome.

BACKGROUND

Despite the lack of definitive evidence to support its efficacy, beta-blocker therapy is widely used prophylactically in patients with Marfan's syndrome.

METHODS

A meta-analysis was instituted, which included studies identified by a systematic review of MEDLINE of peer-reviewed publications and by abstracts from annual scientific meeting. Outcome measures of mortality and major morbidity were compared between patients treated and untreated with beta-blockade therapy. Data was combined according to both a fixed-effects and random-effects model. The endpoints included aortic dissection or rupture, cardiovascular surgery, or death.

RESULTS

Six studies were included, 5 were non-randomized follow-up studies and 1 was a prospective randomized trial (802 patients). Ninety-six of 433 patients treated with beta-blocker therapy and 74 of 369 untreated patients reached designated endpoints. Utilizing a fixed-effects model, patients treated with beta-blocker therapy were more likely to reach an endpoint (odds ratio=1.50 with 95% CI 1.05-2.16). However, by a random-effects model, the treatment effect failed to reach significance (1.54 with 95% CI 0.99-2.40).

CONCLUSIONS

On the basis of this meta-analysis, there is no evidence that beta-blockade therapy has clinical benefit in patients with Marfan's syndrome.

Clinical profiles and outcomes of acute type B aortic dissection in the current era: lessons from the International Registry of Aortic Dissection (IRAD)

BACKGROUND

Clinical profiles and outcomes of patients with acute type B aortic dissection have not been evaluated in the current era.

METHODS AND RESULTS

Accordingly, we analyzed 384 patients (65+/-13 years, males 71%) with acute type B aortic dissection enrolled in the International Registry of Acute Aortic Dissection (IRAD). A majority of patients had hypertension and presented with acute chest/back pain. Only one-half showed abnormal findings on chest radiograph, and almost all patients had computerized tomography (CT), transesophageal echocardiography, magnetic resonance imaging (MRI), and/or aortogram to confirm the diagnosis. In-hospital mortality was 13% with most deaths occurring within the first week. Factors associated with increased in-hospital mortality on univariate analysis were hypotension/shock, widened mediastinum, periaortic hematoma, excessively dilated aorta (>or=6 cm), in-hospital complications of coma/altered consciousness, mesenteric/limb ischemia, acute renal failure, and surgical management (all P<0.05). A risk prediction model with control for age and gender showed hypotension/shock (odds ratio [OR] 23.8, P<0.0001), absence of chest/back pain on presentation (OR 3.5, P=0.01), and branch vessel involvement (OR 2.9, P=0.02), collectively named 'the deadly triad' to be independent predictors of in-hospital death.

CONCLUSIONS

Our study provides insight into current-day profiles and outcomes of acute type B aortic dissection. Factors associated with increased in-hospital mortality ("the deadly triad") should be identified and taken into consideration for risk stratification and decision-making.

Optimal treatment of type B acute aortic dissection: long-term medical follow-up results

BACKGROUND

The aim of this study is to assess the long-term outcome of medical treatment and determine recent surgical indications for type B acute aortic dissection.

METHODS

In the last 8 years, 79 patients were admitted to our hospital with type B acute aortic dissection. We medically treated patients at the time of onset, regardless of the aortic diameter and blood patency status in the false lumen. If the maximum diameter of dissected aorta exceeded 60 mm in any stage, early or elective surgery was performed. The mean follow-up duration was 41.2 months. We evaluated operation free rate and actuarial survival rate.

RESULTS

Thirteen patients underwent early or elective operations of the descending aorta. At the time of onset, the maximum aortic diameter of these patients was significantly larger than that of medically managed patients (55.8 +/- 4.4 mm vs 44.6 +/- 8.2 mm; p = 0.0004). Two patients underwent emergency axillo-femoral bypass for leg ischemia. Of the other 64 patients, who were medically managed, 2 patients had type A dissection develop during follow-up, 3 died during the initial hospital stay (1 from rupture, 1 from bronchial asthma, and 1 from gut ischemia), and 1 died of pneumonia 6 months after onset. Operation free rate was 98.6% at 1 month, 90.0% at 1 year, 78.7% at 3 years, and 69.5% at 8 years. Actuarial survival rate of medically managed patients was 98.4% at 1 month and 93.5% at 8 years.

CONCLUSIONS

Medical treatment of type B acute aortic dissection produced good results. Surgical intervention for type B dissection should be done when the maximum aortic diameter exceeds 60 mm.

Acute atypical type-A thoracic aortic dissection with intramural hematoma: the importance of patient symptoms and the transthoracic echocardiographic examination

This report demonstrates how transthoracic echocardiography, in conjunction with the sonographer's attention to patient symptomatology, heightened the clinical suspicion of an atypical aortic dissection, leading to further investigation and confirmation. Although initially undiagnosed by computed tomography, a structure suggestive of aortic dissection was subsequently found by transthoracic echocardiography. Transesophageal echocardiography and a second computed tomography examination validated the transthoracic findings. An atypical type A aortic dissection with intramural hematoma was confirmed at operation.

Predictors of complications in acute type B aortic dissection

OBJECTIVES

Medical treatment is generally advocated for patients with acute type B aortic dissection without complications. The objective of this retrospective analysis was to determine whether there are any initial findings that can help predict the long-term course of the disease.

METHODS

Case records of the 130 patients treated for type B aortic dissection between 1988 and 1997 were reviewed; 41 (31%) were operated on in the acute phase (<14 days), 31 (24%) were operated on in the chronic phase and 58 (45%) were treated medically.

RESULTS

Overall acute mortality was 10.8%; 22% for patients operated on in the early phase and 5.6% for medically treated patients. Age (P=0.002), persistent pain (P=0.01) and malperfusion (P=0.001) were significant independent predictors of the need for surgery. Paraplegia/para paresis (P=0.0001), leg ischaemia (P=0.003), pleural effusion (P=0.003), rupture (P=0.0001), shock (P=0.0001), age (P=0.003), cardiac failure (P=0.002) and aortic diameter >4.5 cm (P=0.002) were significant predictors of poor survival. Age and shock also emerged as independent risk factors. Patients without malperfusion (P=0.0001), pleural effusion (P=0.003), rupture (P=0.0001) and shock (P=0.0001) had a significantly better event-free survival (freedom from repeat surgery and death). The actuarial survival rate for high-risk patients (malperfusion, rupture, shock) was 62% at 1 year and 40% at 5 years; the corresponding values for low-risk patients were 94 and 84%, respectively.

CONCLUSIONS

Rupture, shock and malperfusion are significant predictors of poor survival in patients with acute type B aortic dissection.

Localized aortic dissection: unusual features by transesophageal echocardiography

Transesophageal echocardiography relies on the presence of an undulating intimal flap for the diagnosis of aortic dissection. Furthermore, to distinguish true dissection from echo artifacts, the flap has to be identified in more than one view, and it must have a motion independent of the aortic wall. We describe the transesophageal echocardiography appearance of a localized aortic dissection with atypical features for an intimal flap. Awareness of this unusual echocardiographic appearance of an intimal flap will avoid misdiagnosis of the potentially serious acute aortic dissection.

Evaluation of flow volume and flow patterns in the patent false lumen of chronic aortic dissections using velocity-encoded cine magnetic resonance imaging

In 21 patients with chronic aortic dissections and proven patent false lumens, the flow volume and flow patterns in the patent false lumens was evaluated using velocity-encoded cine magnetic resonance imaging (VENC-MRI) and the relationship between the flow characteristics and aortic enlargement was retrospectively examined. Flow patterns in the false lumen were divided into 3 groups: pattern A with primarily antegrade flow (n=6), pattern R with primarily retrograde flow (n=3), and pattern B with bidirectional flow (n=12). In group A, the rate of flow volume in the false lumen compared to the total flow volume in true and false lumens (%TFV) and the average rate of enlargement of the maximum diameter of the dissected aorta per year (deltaD) were significantly greater than in groups R and B (%TFV: 74.1+/-0.07 vs 15.2+/-0.03 vs 11.8+/-0.04, p<0.01; deltaD: 3.62+/-0.82 vs 0 vs 0.58+/-0.15 mm/year, p<0.05, respectively). There was a significant correlation between %TFV and deltaD (r=0.79, p<0.0001). Evaluation of flow volume and flow patterns in the patent false lumen using VENC-MRI may be useful for predicting enlargement of the dissected aorta.

Delayed chronic type A dissection following CABG: implications for evolving techniques of revascularization

BACKGROUND

Postoperative dissection in some patients is related to manipulation of the aorta and accounts for 3% to 5% of deaths after cardiac surgery.

METHODS

Between 1987 and 1999, 109 patients with previous cardiac operations were treated for chronic type A dissection. In 31 of the patients, the etiology was related to aortic manipulation. Twenty-one patients (17 men, 4 women; 67+/-13 years of age) had isolated coronary artery bypass grafting (CABG) as their first operation and were reviewed. The interval between operations was 52.9+/-47.3 months.

RESULTS

Reoperation was elective in 11 patients, urgent in 10 patients. Median maximal aortic diameter was 6.8+/-2.1 cm; 9 patients had major aortic insufficiency. The intimal tear was at the partial occlusion clamp site in 12 patients (57.1%), at the cross-clamping site in 4 patients (19.1%), and at the proximal anastomosis in 1 patient (4.8%); 4 patients (19.1%) had multiple tears at several sites. Cystic media necrosis was present in 9.5% of the patients, severe atherosclerosis in 47.6% of the patients, and 42.9% of the patients had both. Nine patients (42.9%) underwent a modified Bentall procedure, 12 patients (57.1%) underwent a supracoronary anastomosis, and all had open distal anastomosis. There were two (9.5%) hospital deaths and three (14.3%) postoperative strokes. Freedom from cardiac or aorta-related mortality was 85.7% at a mean follow-up of 49.3 months.

CONCLUSIONS

In patients who develop type A dissection of the aorta after previous CABG, the intimal tear most often is at partial occlusion clamp site. This complication is associated with morbidity and mortality. It remains to be seen whether the use of partial occlusion clamps on the pulsating and often diseased aorta during off-pump coronary artery bypass (OPCAB) will increase the risk of delayed iatrogenic dissections.

Medical treatment of the aorta. I

Diseases of the thoracic aorta are serious conditions that require close observations. Impressive advances in imaging modalities such as magnetic resonance imaging, computed tomography sacs, and transesophageal echocardiography have aided diagnosis and provided insights into the pathogenesis and natural history of thoracic aortic aneurysms, dissection, and atherosclerosis. The current review highlights the etiology, epidemiology, and pathophysiology of these disorders and focuses on the diagnostic approach and suggested medical therapies in the current era.

Biochemical diagnosis of aortic dissection: from bench to bedside

Aortic dissection is an acute cardiovascular disease associated with high mortality and morbidity. Although uncommon, recent studies have shown that the incidence of this catastrophic disease is steadily increasing. Unfortunately, the disease is still not well recognized on clinical presentation due to lack of specific signs and symptoms. As early diagnosis and initial management are critical for survival, we focused on developing a biochemical diagnostic approach for this disease given its meritorious properties in use in the acute clinical situation and additional projected combined use with established imaging modalities. Studies using an assay developed against smooth muscle myosin heavy chain, a protein which is released from the aortic medial smooth muscle cells on insult to the aortic wall, showed promising results for use of this assay in the diagnosis of aortic dissection. The background of this pioneering assay in addition to its clinical use are discussed in this review.

Complications of transesophageal echocardiography in the ED

The complication rate of transesophageal echocardiography (TEE) performed in clinical settings outside the emergency department (ED) has been reported to be 1% to 3%. The rate of complications of performing TEE in the ED has not been established. The purpose of this study was to determine the rate of complications associated TEE with carried out on ED patients, and to investigate parameters that might predict complications. A retrospective chart review was carried out on consecutive ED patients undergoing TEE at a major referral center. Complications were abstracted. Parameters to predict complications were assessed, including age, gender, vital signs, pulse oximetry values, serum bicarbonate level, and hematocrit level. A total of 142 patients underwent TEE in the ED during the study period; 88 of these were trauma patients. There were 18 (12.6%) complications: death (1), respiratory insufficiency/failure (7), hypotension (3), emesis (4), agitation (2), and cardiac dysrhythmia (1). None of the tested variables predicted a complication. TEE carried out in the ED has a higher complication rate than has been reported in other clinical settings.

Occlusion of the abdominal aorta caused by enlargement of the false lumen after graft replacement for a DeBakey type IIIb dissecting aneurysm: report of a case

We report herein a case of abdominal aorta occlusion caused by enlargement of the false lumen after a graft replacement. The patient was a 70-year-old man who underwent a graft replacement of the descending thoracic aorta for a DeBakey type IIIb dissecting aneurysm. Digital subtraction angiography performed on postoperative day 18 revealed an abdominal aorta occlusion caused by enlargement of the false lumen. A new intimal defect was found in the aortic wall 2 cm distal to the suture line, the cause of which was suspected to be clamp injury during the initial operation. Graft replacement of the abdominal aorta was subsequently carried out. Postoperatively, he had no complications, and digital subtraction angiography showed excellent reconstruction of the abdominal aorta. The patient was discharged from hospital 1 month after his second operation.

Pitfalls in the echocardiographic diagnosis of aortic dissection

The authors studied 25 patients with transthoracic echocardiography (TTE) and/or transesophageal echocardiography (TEE) for suspected aortic dissection. Of these, aortic dissection was diagnosed correctly in 19 patients, but in 6 the echocardiographic findings for dissection were atypical or false-positive. In patient 1, the TEE revealed a dilatated proximal aortic root. TEE showed a possible flap but was nondiagnostic. The diagnosis was made by computed tomography (CT) and confirmed at surgery to be type 1 dissection. In patient 2, the TTE depicted flail aortic cusps, questionable vegetations, and dilatated aortic root. In patient 3, TTE demonstrated moderate pericardial effusion with hematoma but no dissection. Type 1 dissection was subsequently confirmed at autopsy in both. Patient 4 had TEE diagnosis of type 3 dissection. However, reevaluation of the study by a senior sonographer just prior to surgery led to the correct diagnosis of type 1 dissection. Patients 5 and 6 had dilatated ascending aortas with linear echoes within the lumen on TEE and were reported as having type 1 dissections. CT and/or angiography did not reveal dissection in either patient. In conclusion, TTE and TEE are vaulable tests in diagnosing aortic dissection. However, atypical features, misdiagnosis of the site of dissection, or false-positive studies can occur.

Acute thoracic aortic dissection: the basics

With an increasing incidence, aortic dissection is the most common acute illness of the aorta. In the setting of chronic hypertension, with or without other risk factors for aortic dissection, this diagnosis should be considered a diagnostic possibility in patients presenting to the emergency department with acute chest or back pain. Left untreated, about 75% of patients with dissections involving the ascending aorta die within 2 weeks of an acute episode. But with successful initial therapy, the 5-year survival rate increases to 75%. Hence, timely recognition of this disease entity coupled with urgent and appropriate management is the key to a successful outcome in a majority of the patients. This article reviews acute thoracic aortic dissection, including ED diagnosis and management.

Abdominal aortic tailoring for renal, visceral, and lower extremity malperfusion resulting from acute aortic dissection

PURPOSE

The treatment of ischemic complications that result from aortic dissection is a challenging and controversial problem. The purpose of this study was to evaluate aortic tailoring in the management of acute aortic dissection associated with visceral, renal, or lower extremity ischemia.

METHODS

We retrospectively reviewed the clinical courses of seven consecutive patients (five men, two women) with a median age of 68 years (range, 48 to 74 years) from January 1994 to January 1997. All patients underwent an abdominal aortic tailoring procedure for relief of ischemic complications associated with acute aortic dissection (type IIIB, n = 6; type I, n = 1) and a normal-sized aorta.

RESULTS

All seven patients survived and recovered full mesenteric, renal, and lower extremity function. Two patients required temporary hemodialysis in the immediate postoperative period. There has been no significant dilatation of the tailored aortic segments, with an average follow-up of 19 months (range, 1 to 30 months).

CONCLUSIONS

Abdominal aortic tailoring represents a safe and effective method for treating ischemic complications associated with acute aortic dissection and a normal aortic luminal diameter.

Twenty-year follow-up of acute type a dissection: the incidence and extent of distal aortic disease using magnetic resonance imaging

A persistent distal false lumen (PDFL) after surgical repair of type A aortic dissection is the most important factor in determining long-term survival. It has been suggested that changes in surgical technique reduce the incidence of distal false lumen. We report the findings of a 20-year follow-up (mean 5.2 years) on 87 patients who have undergone surgical repair of type A aortic dissection with all survivors undergoing magnetic resonance (MR) scanning of the entire aorta. Early mortality was 27.5%, and actuarial 5-, 10-, and 15-year survival was 65%, 28% and 20% respectively. Early mortality had decreased to 18% in the last 5 years. The most common cause of late death was related to distal aortic disease, accounting for 47% of all late deaths with a peak incidence at 7-10 years after surgery. The incidence of PDFL in survivors was 72%, despite the fact that 82% of all intimal tears were resected at time of operation. Incidence was not affected by extension of the repair into the aortic arch nor by the use of the open technique or Gelatin-Resorcine-Formal tissue glue. In patients with a distal false lumen 6% had reached a maximum aortic diameter of 6 cm in at least one plane on MR scanning and 25% had reached 5 cm. We conclude that if dissection has extended beyond the arch at time of presentation then the choice of surgical technique does not prevent the persistance of a distal false lumen. MR scanning gives ideal anatomical and functional assessment of distal aortic disease and provides the surgeon with all the necessary information to plan the timing and indications for further surgery.

Evaluation of chest pain in the emergency department

The evaluation of chest pain in the emergency setting should be systematic, risk based, and goal driven. An effective program must be able to evaluate all patients with equal thoroughness under the assumption that any patient with chest pain could potentially be having an MI. The initial evaluation is based on the history, a focused physical examination, and the ECG. This information is sufficient to categorize patients into groups at high, moderate, and low risk. Table 14 is a template for a comprehensive chest-pain evaluation program. Patients at high risk need rapid initiation of appropriate therapy: thrombolytics or primary angioplasty for the patients with MIs or aspirin/heparin for the patients with unstable angina. Patients at moderate risk need to have an acute coronary syndrome ruled in or out expediently and additional comorbidities addressed before discharge. Patients at low risk also need to be evaluated, and once the likelihood of an unstable acute coronary syndrome is eliminated, they can be discharged with further evaluation performed as outpatients. Subsequent evaluation should attempt to assign a definitive diagnosis while also addressing issues specific to risk reduction, such as cholesterol lowering and smoking cessation. It is well documented that 4% to 5% of patients with MIs are inadvertently missed during the initial evaluation. This number is surprisingly consistent among many studies using various protocols and suggests that an initial evaluation limited to the history, physical examination, and ECG will fail to identify the small number of these patients who otherwise appear at low risk. The solution is to improve the sensitivity of the evaluation process to identify these patients. It appears that more than simple observation is required, and at the present time, no simple laboratory test can meet this need. However, success has been reported with a number of strategies including emergency imaging with either radionuclides such as sestamibi or echocardiography. Early provocative testing, either stress or pharmaceutic, may also be effective. The added value of these tests is only in their use as part of a systematic protocol for the evaluation of all patients with acute chest pain. The initial evaluation of the patient with chest pain should always consider cardiac ischemia as the cause, even in those with more atypical symptoms in whom a cardiac origin is considered less likely. The explicit goals for the evaluation of acute chest pain should be to reduce the time to treat MIs and to reduce the inadvertent discharge of patients with occult acute coronary syndromes. All physicians should become familiar with appropriate risk stratification of patients with acute chest pain. Systematic strategies must be in place to assure rapid and consistent identification of all patients and the expedient initiation of treatment for those patients with acute coronary syndromes. These strategies should include additional methods of identifying acute coronary syndromes in patients initially appearing as at moderate or low risk to assure that no unstable patients are discharged. All patients should be followed up closely until the cardiovascular evaluation is completed and, when possible, a definitive diagnosis is determined. Finally, this must be done efficiently, cost-effectively, and in a manner that will result in an overall improvement in patient care.

Spectrum of acute dissection of the ascending aorta: a transesophageal echocardiographic study

Transesophageal echocardiography is an accurate tool for the immediate diagnosis of acute aortic dissection. In addition to establishing the diagnosis of dissection, transesophageal echocardiography provides determination of its extent and detection of complications. The purpose of this study was to delineate the full spectrum of abnormalities present in acute dissection of the ascending aorta as assessed by transesophageal echocardiography. Forty consecutive patients with acute ascending aortic dissection were evaluated. Specific attention was paid to complications of aortic valve insufficiency, pericardial effusion, and left ventricular wall motion abnormalities. The aortic arch and the descending aorta were also evaluated for involvement. Quantitative data included measurement of the aorta at the anulus, sinuses, and tubular portion, as well as the proximal and distal descending aortas. An intimal flap was identified in all patients. This was a simple linear tear in 22 patients (55%) and circumferential in eight (20%). A complex tear was noted in 10 patients (25%). The majority of patients (n = 30; 75%) had extension of the dissection into the descending thoracic aorta. At least one communication between the true and false lumens ("entrance point") was identified in 31 patients (78%). Pericardial effusions were noted in 19 patients (48%), only two of whom had a moderate-size effusion. Moderate or severe aortic insufficiency was seen in 18 patients (45%) and regional wall motion abnormalities in six patients. We conclude that acute dissection of the ascending aorta results in a complex or convoluted flap rather than a simple linear tear in many patients. The complication of clinically significant pericardial effusion was rare. Aortic insufficiency is common and can be attributed to multiple mechanisms.

Novel biochemical diagnostic method for aortic dissection. Results of a prospective study using an immunoassay of smooth muscle myosin heavy chain

BACKGROUND

Aortic dissection is one of the most common aortic catastrophes. Although newer diagnostic methods as exemplified by image diagnostic techniques have greatly improved the diagnosis of aortic dissection, the diagnosis is still frequently missed today because the signs and symptoms of the disease are at times obscure. A reliable biochemical diagnostic method for aortic dissection would be beneficial.

METHODS AND RESULTS

A novel biochemical diagnostic method for diagnosis of aortic dissection was developed that uses an immunoassay of monoclonal antibodies to smooth muscle myosin heavy chain. A prospective study was conducted to ascertain the usefulness of the method in the diagnosis of aortic dissection. Twenty-seven patients with aortic dissection admitted within the first 24 hours after onset were enrolled. Serial assay of serum smooth muscle myosin heavy chain showed significant elevations within the first 24 hours after onset of aortic dissection, with levels exceeding 10 ng/mL, with subsequent rapid reductions. The sensitivity of the assay within the first 12 hours was 90% with a specificity of 97%. Analysis of 65 patients with acute myocardial infarction showed that the method could accurately differentiate myocardial infarction from aortic dissection.

CONCLUSIONS

The immunoassay of serum smooth muscle myosin heavy chain is a rapid and reliable biochemical method in the diagnosis of aortic dissection. The potential use of the method in clinical medicine is promising.

Transcatheter Inoue endovascular graft for treatment of canine aortic dissection

We examined whether the Inoue endovascular graft could be used as a device for the treatment of aortic dissection. This graft consists of a cylinder made from a thin Dacron sheet suspended by several extra-flexible wire rings. Aortic dissections were experimentally created in 11 dogs. Using aortography and intravascular ultrasound imaging (IVUS), we selected the size of the graft diameter according to the diameter of the normal descending aorta (distal to aortic dissection) in 5 dogs (group I) and according to the diameter of the true lumen of the aorta within the aneurysm in 6 dogs (group II). The graft was deployed transfemorally through a 15-F long sheath into the aneurysm to close the entry site, immediately after creation of the aortic dissection. The entry was completely closed in all dogs after immediate implantation. All 5 dogs in group I died within 11 days (mean, 7 days) after graft deployment. However, all grafts in group II were tolerated very well and followed up for as long as 5 months. After the follow up, IVUS and aortography showed no rupture of the aortic aneurysmal wall and no migration, leakage, or damage to the graft in any of the 6 dogs. These 6 dogs were sacrificed and autopsy showed that the graft was covered by a thin, translucent, neointima, effectively recreating a new aortic lumen and completely closing the entry of the aneurysm. The Inoue endovascular graft proved to be effective in the long-term treatment of aortic dissection without surgery, when the size of the graft was selected according to the diameter of the true lumen of the aorta within the aneurysm.