Prevalence of Aortic Intimal Defect in Surgically Treated Acute Type A Intramural Hematoma

Computed Tomography Angiography for Aortic Diseases

Aortic pathologies encompass a heterogeneous group of disorders, including acute aortic syndrome, traumatic aortic injury , aneurysm, aortitis, and atherosclerosis. The clinical manifestations of these disorders can be varied and non-specific, ranging from acute presentations in the emergency department to chronic incidental findings in an outpatient setting. Given the non-specific nature of their clinical presentations, the reliance on non-invasive imaging for screening, definitive diagnosis, therapeutic strategy planning, and post-intervention surveillance has become paramount. Commonly used imaging modalities include ultrasound, computed tomography (CT), and MR imaging. Among these modalities, computed tomography angiography (CTA) has emerged as a first-line imaging modality owing to its excellent anatomic detail, widespread availability, established imaging protocols, evidence-proven indications, and rapid acquisition time.

Tailored treatment modality in acute type A intramural hematoma

OBJECTIVES

Intramural hematoma may be generated by a minimal intimal tear. Most surgeries for acute type A intramural hematoma are performed on the proximal aorta alone regardless of the intimal tear site. Under the assumption that major adverse aortic events (MAAEs) would be related to the location of primary intimal tear, we reviewed preoperative computed tomography scan findings.

METHODS

Sixty patients with acute type A intramural hematoma who underwent surgery from January 2008 to December 2019 were retrospectively analyzed. The maximal diameter, maximal thickness of the intramural hematoma, and hematoma thickness ratio of the ascending and descending aortae were measured. MAAEs were defined as newly developed aortic dissection, rupture, newly developed penetrating aortic ulcer (PAU), enlargement of the PAU, and aortic death.

RESULTS

The number of patients with PAU in the descending aorta (dPAU) was significantly higher in the MAAE (+) group. The MAAE (+) group showed lower measurements of the ascending aorta and higher measurements of the descending aorta than the MAAE (-) group. In the univariate analysis, dPAU, hematoma thickness ratio of the ascending and descending aortae, and descending aorta hematoma thickness >8.58 mm were risk factors of MAAE. Intimal tear noted intraoperatively and ascending aorta hematoma thickness >10.25 mm were protective factors of MAAE.

CONCLUSIONS

Aortopathies (ie, PAU, ulcer-like projections, and the hematoma thickness ratio) are important clues to determine the location of intimal tear. Occurrence of MAAEs seems to be highly related to the pathology of the descending aorta. The modalities of treatment for stable acute type A intramural hematoma that do not meet the existing guidelines should be tailored to the location of the intimal tear.

Endovascular treatment of traumatic renal artery pseudoaneurysm with a Stanford type A intramural haematoma: A case report

BACKGROUND

Aortic intramural hematoma (IMH) associated with aortic branch tear and intramurally located pseudoaneurysm after blunt trauma has not been reported. Here, we report a case of progressive type A aortic IMH associated with a pseudoaneurysm arising from the injured proximal renal artery after blunt trauma.

CASE SUMMARY

During logging operations, a 66-year-old man experienced blunt force trauma after being injured by a fallen tree. He arrived at our trauma center with a left flank pain complaint. Computed tomography (CT) revealed a pseudoaneurysm arising from the proximal renal artery (localized within the aortic media) and Stanford type A IMH. A covered stent was deployed along the left main renal artery, bridging the pseudoaneurysm and covering the parent artery, successfully excluding the pseudoaneurysm as confirmed using aortography. However, although the degree of the pseudoaneurysm decreased, follow-up CT revealed remnant pseudoaneurysm, likely caused by an endoleak. Subsequently, a covered stent was additionally installed through the previously deployed covered stent. Successful exclusion of the pseudoaneurysm was confirmed using final aortography. In the 7-mo follow-up CT scan, the IMH and pseudoaneurysm completely disappeared with no evidence of stent-related complications.

CONCLUSION

Endovascular treatment such as stent-graft placement can be an effective and safe treatment for traumatic renal artery injury.

CT of the Difficult Acute Aortic Syndrome

Acute aortic syndrome (AAS) is classically attributed to three underlying pathologic conditions-aortic dissection (AD), intramural hematoma (IMH), and penetrating atherosclerotic ulcer (PAU). In the majority of cases, the basics of image interpretation are not difficult and have been extensively reviewed in the literature. In this article, the authors extend existing imaging overviews of AAS by highlighting additional factors related to the diagnosis, classification, and characterization of difficult AAS cases. It has been well documented that AAS is caused not only by an AD but by a spectrum of lesions that often have overlap in imaging features and are not clearly distinguishable. Specifically, phase of contrast enhancement, flow artifacts, and flapless AD equivalents can complicate diagnosis and are discussed. While the A/B dichotomy of the Stanford system is still used, the authors subsequently emphasize the Society for Vascular Surgery's new guidelines for the description of acute aortic pathologic conditions given the expanded use of endovascular techniques used in aortic repair. In the final section, atypical aortic rupture and pitfalls are described. As examples of pericardial and shared sheath rupture become more prevalent in the literature, it is important to recognize contrast material third-spacing and mediastinal blood as potential mimics. By understanding these factors related to difficult cases of AAS, the diagnostic radiologist will be able to accurately refine CT interpretation and thus provide information that is best suited to directing management. Online supplemental material is available for this article. ^©RSNA, 2021.

Acute Aortic Syndrome Revisited: JACC State-of-the-Art Review

The purpose of this paper is to describe all available evidence on the distinctive features of a group of 4 life-threatening acute aortic pathologies gathered under the name of acute aortic syndrome (AAS). The epidemiology, diagnostic strategy, and management of these patients has been updated. The authors propose a new and simple diagnostic algorithm to support clinical decision making in cases of suspected AAS, thereby minimizing diagnostic delays, misdiagnoses, and unnecessary advanced imaging. AAS-related entities are reviewed, and a guideline to avoid imaging misinterpretation is provided. Centralization of patients with AAS in high-volume centers with high-volume surgeons is key to improving clinical outcomes. Thus, the role of multidisciplinary teams, an "aorta code" (streamlined emergent care pathway), and aortic centers in the management of these patients is boosted. A tailored patient treatment approach for each of these acute aortic entities is needed, and as such has been summarized. Finally, a set of prevention measures against AAS is discussed.

Anatomy, Pathology, and Classification of Aortic Dissection

The incremental understanding of the anatomy and pathophysiology of aortic dissection over the past 250 years has predicated the modern endovascular treatments in use today. Since the early descriptions of aortic dissection, our knowledge of the predisposing factors and hemodynamic disturbances that lead to aortic dissection and overlapping syndromes, including intramural hematoma and penetrating atherosclerotic ulcer, has been fine-tuned, aided by more advanced ultrastructural histopathologic analysis and modern cross-sectional imaging techniques. However, several controversies and ambiguities of the pathophysiology and natural history of aortic dissection persist, leading to ongoing challenges in prevention, clinical diagnosis and treatment. In this review, we aim to describe the anatomy, pathology, and classification of aortic dissection and introduce the pathophysiologic basis for endovascular therapies.

Note the descending aorta: predictors of postoperative major adverse aortic event in pure acute type A intramural hematoma

Background

Intramural hematomas (IMHs) may originate from small intimal tears. Although most surgeries for acute type A IMH are conventionally performed solely at the proximal aorta, regardless of the primary intimal tear site, the remnant aortic remodeling stays important during the follow-up period after surgery.

Methods

Forty-seven patients with “pure” acute type A IMHs who underwent surgery from January 2008 to December 2019 were retrospectively analyzed. Acute type A IMH in the entire region without penetrating aortic ulcer (PAU) and aortic dissection (AD), which upon initial computed tomography (CT), can be considered as an intimal tear site, was defined as “pure” type. The maximal diameter of the aorta, maximal thickness of the IMH, and hematoma thickness ratio (HTR) of the ascending and descending aortae were measured from the preoperative computed tomographic scan. The hematoma thickness index was defined as the HTR of the descending aorta divided by that of the ascending aorta. Major adverse aortic events (MAAEs) were defined as AD, rupture, or newly developed PAU and aortic death. Predictors for postoperative MAAEs were analyzed using preoperative computed tomographic findings.

Results

The measurements of the descending aorta were larger and those of the ascending aorta were smaller in the MAAEs group, than in the corresponding other. The hematoma thickness index was significantly higher in the group with MAAEs, than in the group without; this variable was an independent predictor of MAAEs. During surgery, intimal tears were found in 16/47 (34%) patients. The hematoma thickness index was significantly smaller in the group with intimal tears than in the group without the tears. The aortic measurement appears to reflect the tear site.

Conclusions

Hematoma thickness index was an independent predictor of MAAE after acute type A IMH surgery. Long-term periodical follow-up with early reintervention may, therefore, be necessary to improve outcome in these patients. As the optimal treatment method is still controversial, inferring the location of the primary tear through the hematoma thickness index can be helpful in determining the treatment method.

Focal Intimal Disruption Size at Multidetector CT and Disease Progression in Type B Aortic Intramural Hematoma

Background Recent imaging techniques show that patients with aortic intramural hematoma (IMH) have various sizes of focal intimal disruptions (FIDs) that may affect clinical outcomes. Purpose To evaluate the relationship between size of FIDs detected at multidetector CT and disease progression in patients with type B IMH. Materials and Methods This retrospective study analyzed consecutive patients with type B IMH who underwent multidetector CT at admission within 24 hours after symptom onset from January 2011 to March 2017. FID was defined as a focal contrast material-filled pouch projecting outside of the aorta lumen with a communicating orifice greater than 3 mm. Large FID was defined as an FID of at least 10 mm in length and width and at least 5 mm in depth. Aorta-related events were defined as a composite of aortic rupture, surgical or endovascular aortic repair, progressive aortic enlargement, and development of aortic dissection. Results Seventy-six patients (mean age, 72 years ± 11 [standard deviation]; 54 men) were evaluated. Fifty patients (66%; 50 of 76) had 91 FIDs. Twenty-eight patients had large FIDs and 22 patients had small FIDs. Aorta-related events occurred in 15 of 28 patients with large FIDs, two of 22 patients with small FIDs, and four of 26 patients with no FID. Patients with large FIDs showed lower aorta-related event-free survival rates than did patients with small FIDs or no FID (small FIDS, 63% ± 10 vs 90% ± 7 at 3 years, respectively [P = .001]; and no FIDS, 63% ± 10 vs 84% ± 7 at 3 years, respectively [P = .005]). Multivariable analysis showed that a maximum aortic diameter of at least 40 mm (hazard ratio, 4.8; 95% CI: 1.8, 12.6; P = .001) and large FID (hazard ratio, 3.2; 95% CI: 1.1, 8.9; P = .03) were the independent predictors of aorta-related events. Conclusion A large portion of patients with B-intramural hematoma (IMH) had focal intimal disruption (FID) detected at CT at admission. Large FIDs were associated with disease progression of IMH. © RSNA, 2021 See also the editorial by Raptis and Braverman in this issue. Online supplemental material is available for this article.

Demystifying penetrating atherosclerotic ulcer of aorta: unrealised tyrant of senile aortic changes

This review article describes demographic features, comorbidities, clinical and imaging findings, prognosis, and treatment strategies in penetrating atherosclerotic ulcer (PAU) and closely related entities using google scholar web search. PAU is one of the manifestations of the acute aortic syndrome (AAS) spectrum. The underlying aorta invariably shows atherosclerotic changes or aneurysmal dilatation. Hypertension is the most common contributing factor, with chest or back pain being the usual manifestation. Intramural hematoma (IMH) is the second entity associated with both PAU and aortic dissection (AD), more so with the latter. Chest radiograph can show mediastinal widening, pleural, or pericardial fluid in rupture. Computed tomography angiography (CTA) is the imaging modality of choice to visualize PAU, with magnetic resonance imaging (MRI) and transoesophageal echocardiography (TEE) adding diagnostic value. Lesser-known entities of intramural blood pool (IBP), limited intimal tears (LITs), and focal intimal disruptions (FID) are also encountered. PAU can form fistulous communication with adjacent organs whereas IMH may propagate to dissection. CTA aids in defining the management, open or endovascular options in surgical candidates.

Aortic dissection extending from the brachiocephalic artery during transradial coronary catheterization: a case report

BACKGROUND

Iatrogenic acute aortic dissection (AD) is an extremely rare but devastating complication during cardiac catheterization. It can be treated conservatively if it develops in a retrograde form or manifests as an intramural hematoma (IMH) with a micro-intimal tear in the absence of instability. However, only a few reports exist on its natural course and long-term outcomes.

CASE PRESENTATION

A 78-year-old woman presented to the emergency department with acute chest discomfort. Elective cardiac catheterization was performed via the right radial artery. The patient's brachiocephalic artery was so tortuous that the hydrophilic soft guidewire had to be exchanged for a stiffer one. However, the stiff wire caused the dissection of a tortuous brachiocephalic artery that extended from the sinuses of Valsalva to the proximal descending aorta. Emergent computed tomography showed crescentic aortic wall thickening without a dissection flap. The patient had cardiac tamponade and a gradually thickening thrombosed false lumen. Although the patient was unstable during the first 2 weeks, she was stabilized during hospital stay with only conservative treatment. Consequently, she has been well for over 5 years.

CONCLUSIONS

Even though the patient showed ominous findings, a good prognosis was expected because the AD was mainly retrograde. Furthermore, the thrombosed false lumen mimicked an IMH on imaging. To the best of our knowledge, this is the first report of an extensive iatrogenic AD originating from the brachiocephalic artery during right transradial catheterization that was treated conservatively despite clinical instability.

Prediction of adverse events in patients with initially medically treated type A intramural hematoma

BACKGROUND

Prior studies provided limited data regarding natural history of initially medically treated type A intramural hematoma (IMH).

OBJECTIVES

To develop predictive models for adverse aorta-related events in patients with type A IMH.

METHODS

We performed a retrospective pooled analysis of individual patient data, including baseline clinical and CT characteristics. All patients enrolled were followed up for adverse aorta-related events, defined as a composite of aortic disease-related death and the presence of aortic complications that required aortic invasive treatment.

RESULTS

A total of 172 patients (52.9% men) were included, with a mean age of 61.1 ± 11.2 years. During a median follow-up time of 770.5 (45.3-1695.8) days, 60 patients (34.9%) experienced adverse aorta-related events. In Cox regression model for predicting adverse aorta-related events, hypertension (HR = 3.78, p = .067), MAD (HR = 1.05, p = .018), presence of ULP (HR = 2.43, p = .002) and pericardial effusion (HR = 1.65, p = .061) were independently associated with adverse aorta-related events. A majority of the adverse aorta-related events (n = 46, 76.7%) occurred within acute and subacute phase (90 days) of IMH. In predictive model for 90 days aortic events, MAD≥50.7 mm (OR = 2.79, p = .006) and presence of ULP (OR = 3.20, p = .002) were independent predictors. C statistic of the predictive model were 0.71 (p < .001).

CONCLUSIONS

Predictive models including baseline clinical and CT characteristics as predictors allow for accurate estimation of risk of adverse aorta-related events in patients with type A IMH. The proposed predictive models are helpful for risk estimates and decision making.

A Review on the Surgical Management of Intramural Haematoma of the Aorta

Intramural haematoma (IMH) of the aorta is one of the causes of acute aortic syndrome which often requires emergency or urgent life-saving surgery. In this review, we discuss the pathophysiology, epidemiology, clinical presentation, diagnostic imaging, surgery and clinical outcomes associated with IMH.

Acute type A aortic intramural hematoma and type A aortic dissection: correlation between the intimal tear features and pathogenesis

Background

To determine the prevalence, clinical and imaging features of intimal tear detected by ECG-gated multidetector computed tomography (MDCT) and confirmed by surgery in patients with acute type A intramural hematoma (ATAIMH) and acute type A aortic dissection (AAAD).

Methods

This retrospective study involved analysis of the intimal tear characteristics in 72 consecutive patients with ATAIMH and 209 with AAAD who were diagnosed by MDCT. The size and location of the intimal tear were measured and compared between these two groups of patients. The findings were also compared with those from 28 patients with ATAIMH who underwent surgical treatment to determine the intimal tear features as observed on CT angiography (CTA).

Results

Patients in the ATAIMH group were significantly older than those in the AAAD group (58.6±11.3 vs. 49.4±12.8 years, P<0.001), and females were predominant in the former category (ATAIMH vs. AAAD: 44.4% vs. 27.8%, P<0.01). Marfan syndrome and pregnancy were associated with most of the occurrences of AAAD. Sixty-four patients (88.9%) with ATAIMH were recognized as having intimal tear in the CTA images. The number of aortic segments in the ATAIMH patients was smaller than that in the AAAD patients (4.45±1.56 vs. 5.04±1.72 segments, P<0.01). The distribution of the intimal tear did not show any difference between the two groups. During the surgery, pericardial hemorrhage was observed in a higher proportion of patients in the ATAIMH than in the AAAD group (60.7% vs. 22.1%; P<0.01). In the former category, all of the intimal tears detected using CTA were confirmed during the operation, and the size was significantly larger than measured on the CTA images (6.95±5.12 vs. 19.59±6.51 mm, P<0.001). Six ATAIMH patients progressed to classical aortic dissection (AD) at surgery.

Conclusions

Patients with ATAIMH have a high prevalence of intimal tear, which is significantly smaller than that measured in patients with classic AAAD. Just like AD, ATAIMH may also be triggered by intimal tear. Hence, timely surgical repair is needed.

Diagnosing Aortic Intramural Hematoma: Current Perspectives

Aortic intramural hematoma (AIH) is an entity within the acute aortic syndrome. Combination of a priori probability, clinical history, laboratory blood test and imaging techniques are the basis for diagnosis of AIH. This review is focused on all aspects related to diagnosis of patients with AIH, from clinical to imaging and analytical.

Endovascular repair of type A aortic intramural hematoma accompanied by aberrant right subclavian artery and Kommerell's diverticulum: a case report

Background

The lesions of aberrant right subclavian artery, Kommerell’s diverticulum and type A aortic intramural hematoma are rare, and we usually treat them with open surgery. In some cases patients have increased risk to undergo surgery, the experiences of endovascular or medical treatment are limited.

Case presentation

Here we reported a case of a 53-year-old man with these three entities present with chest and back ache and attempted a novel approach, thoracic endovascular aortic repair, in the absence of surgical treatment. The patient lived over 5 years and this case provides initial experience and lesson about the endovascular and medical management of the uncommon and dangerous disease- type A aortic intramural hematoma with aortic congenital malformation.

Conclusion

Thoracic endovascular aortic repair with medical treatment may be a potential alternative approach for type A aortic intramural hematoma.

Surgery for type A intramural hematoma: a systematic review of clinical outcomes

Background

Management of type A intramural hematoma (IMH) remains controversial, with opinions divided as to whether patients should be treated with early aggressive surgery or a more conservative approach. The present systematic review aims to evaluate the mortality and morbidities following surgery for type A IMH.

Methods

Electronic searches were performed on five databases from dates of inception to December 2018. All studies with surgical outcomes for type A intramural hematoma were identified by two independent researchers and relevant data extracted. Random-effects meta-analysis of proportions or meta-analysis of means were performed to aggregate the data. Survival data were pooled using reconstructed individual patient data derived from Kaplan-Meier curves.

Results

Fifteen studies with 744 patients were identified. Ten studies were from Asian countries (73% of patients). Overall mortality was 8.2% [95% confidence interval (CI): 4.6-13.9%]. Mortality from Asian centers was 5.3% (95% CI: 3.6-7.7%) and 18.9% (95% CI: 7.0-40.4%) in Western centers. Postoperative complications were poorly reported and hence not analyzable. Overall pooled survival of 343 patients from four studies at 1-, 2-, 3-, 5-, and 10-year was 91.8%, 90.2%, 89.2%, 87.7%, and 71.1%, respectively.

Conclusions

There is an acceptable level of risk of death after surgery for type A IMH, though significant variations exist between results from Asian and Western centers. More detailed studies are required to clarify the controversies surrounding management of type A IMH.

Conservative Management of Uncomplicated Acute Type B Intramural Hematoma of the Aorta Not Always Is the Right Solution

The natural course of intramural hematoma (IMH) of the aorta remains unpredictable and despite an increasing amount of literature reports its treatment is still debatable. IMH typically is diagnosed by computed tomography that has permitted to identify specific images whose onset, in uncomplicated cases, appears to be associated to a dismal prognosis. We report on a case series of acute uncomplicated type B IMH in which early detection of such findings, given the expected poor prognosis associated to the aorta-related mortality, suggests the need to shift toward an aggressive endovascular aortic repair in this subset of patients.

Intramural hematoma and penetrating atherosclerotic ulcers of the aorta: uncertainties and controversies

The natural histories of intramural hematoma (IMH) and penetrating atherosclerotic ulcer (PAU) are highly variable as they may progress to aneurysm formation, rupture, or dissection, or even resolve, in the specific case of IMH. Imaging plays an increasingly important role in clinical and surgical management of IMH and PAU. In contrast to ulcer-like projections, images of intramural blood pools have not been widely reported in CT studies of patients with IMH. Understanding the imaging characteristics and the natural course of each of these entities would help clinicians and surgeons to identify patients at greatest risk for bad prognosis and may improve outcomes. This paper discusses the pathophysiology of these entities, the controversies regarding their natural history, and the prognostic factors that should be identified in CT scans.

Acute type B aortic intramural hematoma: the added prognostic value of a follow-up CT

OBJECTIVES

To investigate prognostic significance of follow-up CT findings for initially medically treated type B aortic intramural hematoma (IMH).

METHODS

We performed a retrospective pooled analysis of individual patient data, including baseline and follow-up CT characteristics. All enrolled patients were followed up for adverse aorta-related events, defined as a composite of aortic disease-related death and surgical or endovascular aortic repair.

RESULTS

A total of 238 patients (73.9% men) were included, with a mean age of 58.1 ± 9.8 years. During follow-up, 83 patients (34.9%) experienced adverse aorta-related events, most of the events (83.1%) occurred within 1 month after follow-up CT imaging (n = 69). In the Cox regression model for predicting adverse aorta-related events, baseline maximal aortic diameter (MAD) (HR = 1.05, p = 0.008), ulcer-like projection (ULP) (HR = 2.47, p < 0.001), changes of maximal hematoma thickness (MHT) (HR = 1.22, p < 0.001), newly developed ULP (HR = 4.44, p < 0.001), and newly developed pleural effusion (HR = 2.46, p = 0.002) were powerful independent predictors. In combined predictive model for 1-month aortic events, baseline MHT ≥ 11.8 mm (OR = 4.39, p = 0.001), ULP (OR = 3.98, p < 0.001), changes of MHT (OR = 1.46, p < 0.001), newly developed ULP (OR = 9.27, p = 0.002), and newly developed pleural effusion (OR = 3.45, p = 0.015) were independent predictors. Besides, in patients with pleural effusion at baseline, resorption of pleural effusion was associated with adverse aorta-related events (HR = 0.36, p = 0.027) and 1-month aortic events (OR = 0.23, p = 0.026).

CONCLUSIONS

Follow-up CT findings provide strong and incremental prognostic information for initially medically treated type B IMH, which are helpful for risk estimates and decisions-making.

KEY POINTS

• Follow-up CT provides strong and incremental prognostic information for initially medically treated type B aortic intramural hematoma. • Follow-up CT is highly recommended for type B intramural hematoma in patients who did not receive urgent invasive therapy. • Follow-up CT is helpful for risk estimates and decisions-making.

Evidence of intimal tear in type A intramural hematoma of the aorta: A case series

•

We report two cases of type A intramural hematoma of the aorta.

•

We found radiological and intraoperative evidence of an intimal tear.

•

This finding supports the hypotesis that IMH belong to “aortic dissection” disease.

Introduction

Aortic intramural hematoma (IMH) is described as “dissection without intimal tear” due to rupture of vasa vasorum, which results in bleeding within the tunica media in the absence of intimal disruption or blood flow communication. The aim of our study is to validate perioperative evidence of intimal entry tear in patients with IMH and to suggest that this entity may represent a part of a disease and not a separate disease.

Presentation of cases

We report two patients admitted to our institution with sudden onset thoracic pain. A CT scan showed an aneurysm of the ascending aorta complicated by type A IMH. The patients underwent open operation. Surgical set-up has included right axillary artery as arterial inflow, no cross-clamp before hypothermic circulatory arrest and Kazui protocol for selective antegrade cerebral perfusion. We found no evidence of intimal flap, but we identified an intimal tear in both patients. A hemiarch procedure associated with root replacement, using two-grafts techniques was performed in both cases. The postoperative course was uneventful and the patients were discharged home.

Discussion

Recent data are emerging from the radiologic literature about the evidence of intimal lesions in IMH, but surgical reports are scant. The evidence of intimal tears contributes to consider as questionable the etiological role of vasa vasorum and it may justify updates in the management.

Conclusion

We consider that IMH may represent a part of a disease (aortic dissection), depicted by radiological images in a specific single instant of its clinical evolution.

Precipitous Resolution of Type-A Intramural Hematoma with Medical Management in a Patient with Metastatic Stage 4 Renal Cell Carcinoma

Intramural hematoma (IMH) is a variant form of aortic dissection characterized by involvement of the aortic media without the presence of an overt intimal flap. Surgical extirpation is the standard of care for type-A IMH in the Western world. However, a conservative approach with anti-impulse therapy has been advocated especially in Japan as a viable alternative. Here, we report a case of an elderly male patient with a history of metastatic stage 4 renal cell carcinoma who was treated with anti-impulse therapy for an acute type-A IMH. Blood pressure stabilization and continuous monitoring resulted in complete resolution of the IMH within 6 days. This report illustrates how immediate medical management in patients with acute type-A IMH who are not surgical candidates can alleviate the progression or even lead to regression as early as 1 week after initiating anti-impulse therapy.

Aortic intramural hemorrhage: A distinct disease entity with mystery

Aortic intramural hemorrhage (IMH) is one of the disease processes that comprise the spectrum of acute aortic syndrome (AAS) with clinical manifestations and a mortality rate similar to those of classic aortic dissection (AD). However, IMH should be considered as a distinct disease entity rather than a precursor to classic dissection because of differences in their pathology, etiology, natural history, and imaging findings. Multidetector computed tomography (CT) is recommended as the first-line diagnostic imaging modality for IMH, but transesophageal echocardiography (TEE) and magnetic resonance imaging (MRI) are also helpful. There is still debate over the appropriate treatment of IMH. Medical treatment of type B IMH appears effective and safe, while surgical treatment is recommended for type A IMH. Thoracic endovascular aortic repair (TEVAR) is a promising treatment for selected patients, and more clinical evidence needs to be assembled.

Acute aortic syndrome

Acute aortic syndrome (AAS) is a term used to describe a constellation of life-threatening aortic diseases that have similar presentation, but appear to have distinct demographic, clinical, pathological and survival characteristics. Many believe that the three major entities that comprise AAS: aortic dissection (AD), intramural hematoma (IMH) and penetrating aortic ulcer (PAU), make up a spectrum of aortic disease in which one entity may evolve into or coexist with another. Much of the confusion in accurately classifying an AAS is that they present with similar symptoms: typically acute onset of severe chest or back pain, and may have similar radiographic features, since the disease entities all involve injury or disruption of the medial layer of the aortic wall. The accurate diagnosis of an AAS is often made at operation. This manuscript will attempt to clarify the similarities and differences between AD, IMH and PAU of the ascending aorta and describe the challenges in distinguishing them from one another.

Preoperative characteristics and surgical outcomes of acute intramural hematoma involving the ascending aorta: A propensity score-matched analysis

OBJECTIVE

We aimed to evaluate the preoperative characteristics and surgical outcomes of acute type A intramural hematoma.

METHODS

Between January 2000 and June 2011, 460 consecutive patients underwent emergency open surgery for type A acute aortic syndrome at Sakakibara Heart Institute. Among these patients, 121 had intramural hematoma and 339 had typical aortic dissection. We compared the clinical characteristics and surgical outcomes using propensity score matching.

RESULTS

In all patients, the intramural hematoma group had an older age (69.2 ± 10.4 years vs 63.4 ± 13.5 years; P < .001), included a higher ratio of female patients (56.2% vs 44.0%, P = .020), and more frequently had hypertension (94.2% vs 83.5%, P = .005), hyperlipidemia (25.6% vs 12.7%, P < .001), and cardiac tamponade (33.1% vs 18.3%, P < .001) than patients with aortic dissection. Cerebral malperfusion (0.8% vs 5.3%, P = .033), myocardial malperfusion (0.8% vs 8.2%, P = .002), lower limb malperfusion (1.7% vs 7.9%, P = .015), Marfan syndrome (0% vs 3.5%, P = .042), and aortic valve insufficiency (2.5% vs 15.0%, P < .001) were less frequently observed in the intramural hematoma group than in the aortic dissection group. After propensity score matching, 116 matched pairs were created. In the matched analysis, operative mortality was 0.9% in the intramural hematoma group (1/116) and 3.4% in the aortic dissection group (4/116, P = .179). The intramural hematoma group demonstrated higher actuarial 1- and 5-year survivals than the aortic dissection group (99.1 % vs 93.6% and 97.3% vs 85.9%, respectively, P = .006). In the multivariate analysis, intramural hematoma was shown to be associated with lower midterm mortality (hazard ratio, 0.316; 95% confidence interval, 0.102-0.974; P = .045).

CONCLUSIONS

Patients with intramural hematoma have different preoperative clinical characteristics compared with patients with aortic dissection. Emergency open surgery for type A intramural hematoma demonstrated low operative mortality and excellent 5-year survival.

MDCT distinguishing features of focal aortic projections (FAP) in acute clinical settings

Focal aortic projections (FAP) are protrusion images of the contrast medium (focal contour irregularity, breaks in the intimal contour, outward lumen bulging or localized blood-filled outpouching) projecting beyond the aortic lumen in the aortic wall and are commonly seen on multidetector computed tomography (MDCT) scans of the chest and abdomen. FAP include several common and uncommon etiologies, which can be demonstrated both in the native aorta, mainly in acute aortic syndromes, and in the post-surgical aorta or after endovascular therapy. They are also found in some types of post-traumatic injuries and in impending rupture of the aneurysms. The expanding, routine use of millimetric or submillimetric collimation of current state-of-the-art MDCT scanners (16 rows and higher) all the time allows the identification and characterization of these small ulcer-like lesions or irregularities in the entire aorta, as either an incidental or expected finding, and provides detailed three-dimensional pictures of these pathologic findings. In this pictorial review, we illustrate the possible significance of FAP and the discriminating MDCT features that help to distinguish among different types of aortic protrusions and their possible evolution. Awareness of some related and distinctive radiologic features in FAP may improve our understanding of aortic diseases, provide further insight into the pathophysiology and natural history, and guide the appropriate management of these lesions.

Current understandings and approach to the management of aortic intramural hematomas

Intramural hematoma is the most enigmatic of the 3 lethal entities comprising acute aortic syndrome. Despite being identified almost 100 years ago, there is considerable controversy surrounding the definition, etiology, management, and the very existence of intramural hematoma. The following review outlines these controversies and discusses their effect on management strategies.

Update in acute aortic syndrome: intramural hematoma and incomplete dissection as new disease entities

Acute aortic syndrome is a relatively recent clinical entity. Non-invasive imaging methods, such as computed tomography and transesophageal echocardiography, have contributed significantly to the diagnosis of variant forms of classic aortic dissection, which have become important disease entities in acute aortic syndrome. Imaging findings may result in risk stratification and application of different treatment options, providing a rational approach to achieve a better outcome of this syndrome. This review will focus on the imaging characteristics of two important variant forms of classic aortic dissection, intramural hematoma and incomplete dissection, and the role of imaging methods in the evaluation of differences in the hemodynamic status of false lumens that contributes to patient prognosis.

Prognostic factors in patients with uncomplicated acute type B aortic dissection

BACKGROUND

The benefit of thoracic endovascular aortic repair (TEVAR) for uncomplicated acute type B aortic dissection is unclear. Reliable prognostic factors are needed to identify candidates for prophylactic TEVAR. The aim of this study was to detect prognostic factors in patients with uncomplicated acute type B aortic dissection.

METHODS

From January 2003 to April 2012, a total of 228 patients with uncomplicated acute type B aortic dissection were admitted to our institute. Cox proportional hazards analysis was performed to identify risk factors for death, dissection-related death, and aortic events.

RESULTS

Independent predictors of mortality were age (hazard ratio [HR], 1.08; p < 0.001) and false lumen thickness (mm) (HR, 1.10; p = 0.013), and the risk factor for dissection-related death was false lumen thickness (mm) (HR, 1.14; p < 0.001). Independent risk factors for aortic events were diameter of the descending aorta (mm) (HR, 1.14; p < 0.001) and entry in a proximal site (HR, 2.90; p = 0.02). The actuarial freedom from aortic events in patients with a descending aortic diameter of less than 40 mm and no entry in a proximal site at 1, 3, and 5 years was 96.6%, 90.8%, and 82.5%, respectively, whereas in patients with 1 of these 2 factors, it was 80.1%, 66.8%, and 53.5%, respectively.

CONCLUSIONS

In uncomplicated acute type B aortic dissection, the diameter of the descending aorta and entry in a proximal site were independent prognostic factors for aortic events. Prophylactic TEVAR should be considered for patients with these risk factors.

Imaging modalities for the early diagnosis of acute aortic syndrome

The term acute aortic syndrome (AAS) incorporates aortic dissection, intramural haematoma, and penetrating atherosclerotic ulcer. The common feature of these entities is disruption of the medial layer of the aortic wall. Owing to the life-threatening nature of these conditions, prompt and accurate diagnosis is of paramount importance--misdiagnosis can be fatal. The noninvasive imaging techniques that have a fundamental role in the diagnosis and management of patients with AAS include CT, MRI, transoesophageal echocardiography (TEE), and transthoracic echocardiography (TTE). CT is the most-commonly used imaging modality owing to its wide availability, accuracy, and large field of view. CT plus TTE is the best combination for diagnosing AAS and its complications, and allows important morphological and dynamic aspects of AAS to be assessed and appropriately managed. Ideally, TEE should be performed immediately before surgery or endovascular treatment, in the operating theatre and under general anaesthesia. In stable patients with an uncertain diagnosis of intramural haematoma despite high clinical suspicion, MRI is the technique of choice to make a definitive diagnosis. Imaging techniques have an important role in the primary diagnosis, treatment strategy, and risk stratification of patients with AAS.

Acute aortic syndromes

Acute aortic syndrome is a term that describes one of a number of different pathologic entities. Each of these conditions requires urgent or emergent evaluation and may possibly require surgical intervention. However, both entities may be unfamiliar to the nonsurgical (and in some cases, surgical) practitioner and they may mimic more common diseases or be missed entirely. An understanding of the processes, nomenclature, and management options is critical in optimizing patient care.

Diagnostic errors in the evaluation of nontraumatic aortic emergencies

Nontraumatic aortic emergencies (NTAE) are a complex and dynamic group of serious, potentially fatal conditions affecting the aorta. These entities most often present in the emergency department setting, and include aortic dissection, intramural hematoma, penetrating atherosclerotic ulcer, as well as aortic rupture and impending rupture. The radiologist plays a critical role in prompt diagnosis and evaluation since presenting signs and symptoms are often nonspecific. This article focuses on the potential sources of error in the imaging evaluation of patients presenting with NTAE.

Aortic branch artery pseudoaneurysms associated with intramural hematoma: when and how to do endovascular embolization

PURPOSE

To describe when and how to perform endovascular embolization of aortic branch artery pseudoaneurysms associated with type A and type B intramural hematoma (IMH) involving the descending thoracic and abdominal aorta (DeBakey I and III) that increased significantly in size during follow-up.

MATERIALS AND METHODS

Sixty-one patients (39 men; mean ± standard deviation age 66.1 ± 11.2 years) with acute IMH undergoing at least two multidetector computed tomographic examinations during follow-up for 12 months or longer were enrolled. Overall, 48 patients (31 men, age 65.9 ± 11.5) had type A and type B IMH involving the descending thoracic and abdominal aorta (DeBakey I and III).

RESULTS

Among the 48 patients, 26 (54 %; 17 men, aged 64.3 ± 11.4 years) had 71 aortic branch artery pseudoaneurysms. Overall, during a mean follow-up of 22.1 ± 9.5 months (range 12-42 months), 31 (44 %) pseudoaneurysms disappeared; 22 (31 %) decreased in size; two (3 %) remained stable; and 16 (22 %) increased in size. Among the 16 pseudoaneurysms with increasing size, five of these (three intercostal arteries, one combined intercostobronchial/intercostal arteries, one renal artery), present in five symptomatic patients, had a significant increase in size (thickness >10 mm; width and length >20 mm). These five patients underwent endovascular embolization with coils and/or Amplatzer Vascular Plug. In all patients, complete thrombosis and exclusion of aortic pseudoaneurysm and relief of back pain were achieved.

CONCLUSION

Aortic branch artery pseudoaneurysms associated with type A and type B IMH involving the descending thoracic and abdominal aorta (DeBakey I and III) may be considered relatively benign lesions. However, a small number may grow in size or extend longitudinally with clinical symptoms during follow-up, and in these cases, endovascular embolization can be an effective and safe procedure.