Pathologic Characteristics and Surgical Indications of Superacute Type A Intramural Hematoma

Acute type a aortic intramural hematoma complicated with preoperative hemopericardium: early and late surgical outcome analyses

BACKGROUND

Acute type A aortic intramural hematoma (ATAIMH) is a variant of acute type A aortic dissection (ATAAD), exhibiting an increased risk of hemopericardium and cardiac tamponade. It can be life-threatening without emergency treatment. However, comprehensive studies of the clinical features and surgical outcomes of preoperative hemopericardium in patients with ATAIMH remain scarce. This retrospective study aims to investigate the clinical features and early and late outcomes of patients who underwent aortic repair surgery for ATAIMH complicated with preoperative hemopericardium.

METHODS

We investigated 132 consecutive patients who underwent emergency ATAIMH repair at this institution between February 2007 and August 2020. These patients were dichotomized into the hemopericardium (n = 58; 43.9%) and non-hemopericardium groups (n = 74; 56.1%). We compared the clinical demographics, surgical information, postoperative complications, 5-year cumulative survival rates, and freedom from reoperation rates. Furthermore, multivariable logistic regression analysis was utilized to identify independent risk factors for patients who underwent re-exploration for bleeding.

RESULTS

In the hemopericardium group, 36.2% of patients presented with cardiac tamponade before surgery. Moreover, the hemopericardium group showed higher rates of preoperative shock and endotracheal intubation and was associated with an elevated incidence of intractable perioperative bleeding, necessitating delayed sternal closure for hemostasis. The hemopericardium group exhibited higher blood transfusion volumes and rates of re-exploration for bleeding following surgery. However, the 5-year survival (59.5% vs. 75.0%; P = 0.077) and freedom from reoperation rates (93.3% vs. 85.5%; P = 0.416) were comparable between both groups. Multivariable analysis revealed that hemopericardium, cardiopulmonary bypass time, and delayed sternal closure were the risk factors for bleeding re-exploration.

CONCLUSIONS

The presence of hemopericardium in patients with ATAIMH is associated with an elevated incidence of cardiac tamponade and unstable preoperative hemodynamics, which could lead to perioperative bleeding tendencies and high complication rates. However, patients of ATAIMH complicated with hemopericardium undergoing aggressive surgical intervention exhibited long-term surgical outcomes comparable to those without hemopericardium.

Clinical characteristics and outcomes in patients with acute type A aortic intramural hematoma

BACKGROUND

Although type A acute aortic dissection (AAD) including classic double-channel aorta and intramural hematoma (IMH) is a life-threatening condition, the prognostic impact and predictors of IMH remain to be established. The present study evaluated the prevalence, baseline characteristics, and outcomes of IMH as compared with classic non-thrombosed type A AAD.

METHODS

This multicenter registry in Japan retrospectively included 703 patients with type A AAD. IMH was defined as a crescentic or circular area along the ascending aortic wall without contrast enhancement on computed tomography (CT). Non-thrombosed type A AAD was defined as the classic double-channel ascending aorta on contrast-enhanced CT. The primary endpoint was in-hospital mortality.

RESULTS

Of the 703 patients with type A AAD, 312 (44.3%) had IMH. Older age was an only baseline patient factor significantly associated with the presence of IMH in the multivariable analysis. The longitudinal extent of dissection was greater in patients with classic non-thrombosed AAD than those with IMH, resulting in an increased risk of end-organ malperfusion in the classic AAD group. During the hospitalization, 41 (13.1%) and 85 (21.7%) patients with and without IMH died (p < 0.001). IMH was associated with lower in-hospital mortality in a multivariable model, irrespective of age and the implementation of surgery.

CONCLUSIONS

The present study showed that IMH on CT was frequent among patients with type A AAD. Although IMH was more likely to be present in the elderly, its effect on the better survival was independent of age and surgical treatment.

Clinical and imaging differences between Stanford Type B intramural hematoma-like lesions and classic aortic dissection

BACKGROUND

Intramural hematoma (IMH) and Aortic dissection (AD) have overlapping features. The aim of this study was to explore the differences between them by comparing the clinical manifestations and imaging features of patients with acute Stanford type B IMH-like lesions and acute Stanford type B AD (ATBAD).

METHODS

This study retrospectively analysed the clinical and computed tomography angiography (CTA) imaging data of 42 IMH-like lesions patients with ulcer-like projection (ULP) and 38 ATBAD patients, and compared their clinical and imaging features.

RESULTS

(1) The IMH-like lesions patients were older than the ATBAD patients (64.2 ± 11.5 vs. 50.9 ± 12.2 years, P < 0.001). The D-dimer level in the IMH-like lesions group was significantly higher than that in the ATBAD group (11.2 ± 3.6 vs. 9.2 ± 4.5 mg/L, P < 0.05). The incidence rate of back pain was significantly higher in the ATBAD group than in the IMH-like lesions group (71.1% vs. 26.2%, P < 0.05). (2) The ULPs of IMH-like lesions and the intimal tears of ATBAD were concentrated in zone 4 of the descending thoracic aorta. The ULPs of IMH-like lesions and the intimal tears of ATBAD were mainly in the upper quadrant outside the lumen (64.3% vs. 65.8%, P > 0.05). (3) The maximum diameter of the ULPs in IMH-like lesions was smaller than that of the intimal tears in ATBAD (7.4 ± 3.4 vs. 10.8 ± 6.8 mm, P = 0.005). The lumen compression ratio in the ULPs plane and the maximum compression ratio of the aortic lumen in the IMH-like lesions group were smaller than that in the ADBAD group (P < 0.05). Fewer aortic segments were involved in IMH-like lesions patients than in ATBAD patients (5.6 ± 2.2 vs. 7.1 ± 1.9 segments, P < 0.005). The IMH-like lesions group had less branch involvement than that of the ATBAD group (P < 0.001).

CONCLUSION

The degree of intimal tears, lumen compression ratio, extent of lesion involvement, and impact on branch arteries in ATBAD are more severe than that of IMH-like lesions. But for the ULPs of IMH-like lesions and intimal tears of ATBAD, they have astonishing similarities in the location of the partition and the lumen quadrant, we have reason to believe that intimal tear is the initial factor in the pathogenesis of this kind of disease, and their clinical and imaging manifestations overlap, but the severity is different. Concerning similarities between these two conditions, these two may be a spectrum of one disease.

Comparison of population characteristics and clinical outcomes of patients with type B aortic dissection or aortic intramural hematoma underwent thoracic endovascular aortic repair: a propensity score-matched analysis

BACKGROUNDS

Survival and aortic-related adverse events after thoracic endovascular aortic repair (TEVAR) for aortic intramural hematoma (IMH) and aortic dissection (AD) are controversial. We aimed to assess the preoperative characteristics and to evaluate TEVAR outcomes of acute type B IMH and AD.

METHODS

Between June 2002 and May 2021, 83 patients with acute type B IMH and 755 patients with acute type B AD underwent TEVAR at the General Hospital of Northern Theater Command. We retrospectively analyzed data from these patients, including clinical characteristics and follow-up outcomes.

RESULTS

The patients with IMH were significantly older than the ones with AD (P < 0.001). Diabetes mellitus (P = 0.035) and ischemic cerebrovascular disease (P = 0.017) were more common in the IMH group than in the AD group. The results demonstrated a less long-term aortic-related death-free survival rate in the IMH group than the AD group for all the patients (P = 0.014) and the matched patients (P = 0.027). It also presents a lower long-term overall survival rate (P = 0.047) and aortic-related event-free rate (P = 0.048) in the IMH group than in the matched patients.

CONCLUSIONS

Compared with AD patients, patients with IMH who underwent TEVAR had a worse long-term outcome of aortic-related survival in all and matched patients.

Location of the False Lumen Within the Medial Layer in Acute Intramural Hematoma

BACKGROUND

We compared the location of the false lumen within the medial layer between acute intramural hematoma (AIH) and acute aortic dissection (AAD) using microscopic images of aortic specimens and examined the associations with patient characteristics, CT findings, and late outcomes.

METHODS AND RESULTS

Among 293 patients undergoing surgery for Stanford type A acute aortic syndrome between 2008 and 2018, 45 patients had neither an identifiable intimal tear, flow to the false lumen on preoperative CT or intimal tear by intraoperative observation (AIH group), and 98 patients with patent false lumen were enrolled (AAD group). The AIH group had a significantly thinner outer media thickness (OMT) than the AAD group. The AIH group showed more pericardial effusion, but distal progression of dissection and branch vessel involvement were limited. The change in aortic diameter after surgery was insignificant in the AIH group, whereas in the AAD group it continued to increase. Cumulative incidence of aortic adverse events was significantly higher among AAD patients, but no significant difference was observed in survival between groups.

CONCLUSIONS

The AIH group had a significantly thinner OMT than the AAD group, which was significantly associated with a large amount of pericardial effusion, greater false lumen diameter, and limited progression of aortic dissection.

Acute Cardiac Emergencies

Acute cardiac emergencies are life threatening. The initial responses to acute cardiac emergencies must be rapid, efficient, skillful, and well-planned. The goal of this article is to provide information that can be used to facilitate the prompt recognition and treatment of the most common acute cardiac emergencies.

Outer Media Thickness at False Lumen and Secondary Aortic Dilatation After Acute Aortic Dissection

BACKGROUND

This study measured the outer media thickness (OMT) at the false lumen by using microscopic images of specimens collected intraoperatively and assessed the impact of OMT on secondary dilatation of the downstream aorta.

METHODS

Of 238 patients undergoing surgical procedures for acute type A dissection between 2007 and 2016, 129 patients fulfilled the inclusion criteria for this study: DeBakey type I dissection with a patent false lumen, histopathologic examination of full-thickness aortic wall, and at least 1 follow-up computed tomographic scan at more than 3 months after surgical procedures. On average, 5.1 scans were obtained per patient, and median follow-up was 4.3 years.

RESULTS

Considerable variation was observed in OMT (median, 0.21 mm; range, 0.04-0.51 mm). The aortic diameter growth rate was inversely correlated with the OMT, and in the lowest tertile of OMT the aortic diameter dilated significantly faster in the first year than later and faster than in the other tertiles. Multivariable Fine-Gray analysis, with death as the competing risk, identified OMT as an independent variable for aortic-related events. Patients with OMT of 0.04 to 0.15 mm had a 3.54-fold higher risk of aortic-related events and those with 0.16 to 0.31 mm had a 1.56-fold higher risk of aortic-related events than did patients with OMT of 0.32 to 0.51 mm. Multivariable Cox regression analyses revealed OMT of 0.04 to 0.15 mm as an independent variable for all-cause mortality.

CONCLUSIONS

In patients with DeBakey type I aortic dissection with a patent false lumen, the growth rate of the distal residual dissecting aorta was inversely correlated with the OMT. The risk of aortic-related events was significantly higher in patients with OMT of 0.04 to 0.15 mm.

Aortic Dissection and Other Acute Aortic Syndromes: Diagnostic Imaging Findings from Acute to Chronic Longitudinal Progression

Acute aortic dissection is the prototype of acute aortic syndromes (AASs), which include intramural hematoma, limited intimal tear, penetrating atherosclerotic ulcer, traumatic or iatrogenic aortic dissection, and leaking or ruptured aortic aneurysm. The manifestation is usually sudden and catastrophic with acutely severe tearing chest or back pain. However, clinical symptoms do not allow distinction between AAS types and other acute pathologic conditions. Diagnostic imaging is essential to rapidly confirm and accurately diagnose the type, magnitude, and complications of AASs. CT fast acquisition of volumetric datasets has become instrumental in diagnosis, surveillance, and intervention planning. Most critical findings affecting initial intervention and prognosis are obtained at CT, including involvement of the ascending aorta, primary intimal tear location, rupture, malperfusion, size and patency of the false lumen, complexity and extent of the dissection, maximum caliber of the aorta, and progression or postintervention complications. Involvement of the ascending aorta-Stanford type A-has the most rapid lethal complications and requires surgical intervention to affect its morbidity and mortality. Lesions not involving the ascending aorta-Stanford type B-have a lesser rate of complications in the acute phase. During the acute to longitudinal progression, various specific and nonspecific imaging findings are encountered, including pleural and pericardial effusions, fluid collections, progression including aortic enlargement, and postoperative changes that can be discerned at CT. A systematic analysis algorithm is proposed for CT of the entire aorta throughout the continuum of AASs into the chronic and posttreated disease state, which synthesizes and communicates salient findings to all care providers. Online supplemental material is available for this article. ^©RSNA, 2021.

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.

Optimal timing of type A intramural hematoma repair

Acute type A aortic intramural hematomas (IMHs) are often included under the spectrum of acute aortic syndromes. The classical definition is the presence of hematoma in the media without identifiable intimal tear. Dissection occurring within two weeks of presentation is defined as acute. Acute type A IMH remains a subject of debate, especially regarding its definition and management. The classical theory of pathogenesis of IMHs is ruptured vasa vasorum in the aortic media. However, the majority of IMHs are now detected with an intimal defect using high-resolution computed tomography and intravascular ultrasound, which implies that IMHs may be a subset of aortic dissections (ADs), with very limited flow in the false lumen. Much controversy remains regarding IMH differences in presentation, diagnosis, and risk for progression. Geographic location and ethnicity, especially Asian vs. Western, possibly affect the natural history and outcomes of acute type A IMH. In this review, we describe the pathophysiology and management strategies for acute type A IMHs.

Management of retrograde type A IMH with acute arch tear/type B dissection

The incidence of intramural hematomas (IMH) in acute dissection (AD) patients varies between 6% and 30% in the literature, most frequently involving only the descending aorta (58%) than the arch or ascending aorta (42%). In this setting, IMH that initiate in the descending aorta, but extend into the arch or ascending aorta have been described, and referred to as a retrograde type A IMH. In these patients the risk of neurological or cardiac complications are high, and therefore an open surgical or hybrid approach has been proposed as the most appropriate. Nevertheless, the endovascular management of such lesions in surgically unfit patients for open surgery have been offered with acceptable outcomes, although the risk of landing in an unsuitable proximal landing zone is evident. In conclusion, retro-TAIMH is an acute aortic syndrome and should be managed as such. The recommended treatment strategy is open surgery for treating ascending or arch involvement, and TEVAR/medical, based on a complication-specific approach, for those with only descending localization. In those patients in whom retro-TAIMH is associated with an acute B dissection presenting with a proximal entry tear located into the descending aorta, a TEVAR represents an option treatment.

CT imaging of complications of aortic intramural hematoma: a pictorial essay

Aortic intramural hematoma (IMH) is a pathologic process with a clinical presentation identical to aortic dissection and associated with significant morbidity and mortality. Radiologists must be familiar with the imaging appearances of IMH as computed tomography (CT) plays a critical role in both diagnosis and patient management. The course of IMH is variable and the process may regress, remain stable, or progress in extent and therefore imaging findings associated with a negative prognosis must be recognized and included in the formal radiology report. Potentially life-threatening complications and findings associated with IMH include hemopericardium and cardiac tamponade, coexisting aortic dissection, ulcer-like projection, intramural blood pool, and extension of hematoma along the pulmonary or coronary arteries, which are identifiable with aortic protocol CT. The purpose of this pictorial review is to provide the reader with an image-based review of the diagnostic criteria, related complications, and associated critical prognostic features in patients presenting with aortic IMH.

[Type A intramural hematoma of aorta: An undervalued clinical entity]

Intramural hematoma of the ascending aorta occurs after rupture of the vasa vasorum. Previously considered as a first step of acute aortic dissection, it was later defined as a separate entity that may or may not lead to arterial dissection. The debate about the most appropriate treatment for a 69-year-old patient with intramural hematoma of the ascending aorta, led to this extensive review of the literature demonstrating that intramural hematoma type A is a life-threatening condition requiring urgent surgical support.

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.

Pathophysiology and Surgical Treatment of Type A Acute Aortic Dissection

Objectives: We report the pathophysiology and treatment results of type A acute aortic dissection from our 20-year experience.

METHODS

We studied 673 patients with type A acute aortic dissection who underwent initial treatment from 1994 through July 2014. We divided these patients into two groups. The former group comprised 448 patients from 1994 through 2008, and the latter group comprised 225 patients from 2009 onward, when the current strategy of initial treatment and surgical technique including the early organ reperfusion therapies were established. Results: Women were significantly often presented than men in patients over 60 years of age. Thrombosed-type dissection accounted for more than half in patients over 70 years, and significantly often complicated pericardial effusion and cardiac tamponade than patent type. Malperfusion occurred in 26% of patients. Central repair operations were performed in 579 patients. In-hospital mortality for all patients was 15%, and for the patients who underwent central repair operations was 10%. Former period of operation, malperfusion, and preoperative cardiopulmonary arrest were significant risk factor of in-hospital death. Preoperative left main trunk (LMT) stents were placed in eight patients and superior mesenteric artery (SMA) intervention was performed in five, they were effective to improve the outcome. From 2009 onward, in-hospital mortality was 5.0% and there was no significant risk factor. Conclusion: Surgical results of type A acute aortic dissection were dramatically improved in the past 20 years. Early reperfusion strategy for the patients with malperfusion improved the outcomes. (This article is a translation of Jpn J Vasc Surg 2015; 24: 127-134.).

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.

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.

Intramural haematoma should be referred to as thrombosed-type aortic dissection

OBJECTIVES

Intramural haematoma is defined pathologically as aortic dissection without an intimal tear. We therefore believe that this term is inappropriate as an acute clinical diagnosis, and instead, use the term 'thrombosed-type acute aortic dissection'. We compared the features of thrombosed-type acute aortic dissection with those of classic dissection.

METHODS

Thrombosed type was defined as aortic dissection without flow in the false lumen of the aorta on contrast-enhanced computed tomography. Surgery was indicated for all cases of type A acute aortic dissection, and central repair operations were performed in 509 patients. We retrospectively studied these patients' surgical records.

RESULTS

Three hundred and forty-four patients (68%) had classic dissection, and 165 (32%) had thrombosed type. Thrombosed type was associated with a significantly higher mean age (69 vs 60 years, P < 0.01), a higher incidence of cardiac tamponade (45 vs 28%, P < 0.01) and a lower incidence of malperfusion (6 vs 35%, P < 0.01) than classic dissection. Entry tears were located in the ascending aorta and the arch in 74 patients (45%) with thrombosed type. Since 2007, an intimal tear has been confirmed intraoperatively or on computed tomography in 39 (78%) of 50 patients with thrombosed-type aortic dissection. Mortality was significantly lower in patients with thrombosed-type dissection (6%) than in those with classic dissection (13%, P = 0.02).

CONCLUSIONS

Most cases of intramural haematoma are acute aortic dissections with an intimal tear without re-entry. Intramural haematoma should be referred to as thrombosed-type acute aortic dissection. Thrombosed type can be easily diagnosed on contrast-enhanced computed tomography and has features distinct from those of classic dissection. Our classification may be useful for the diagnosis of these types of aortic dissection.

Acute aortic intramural hematoma: an analysis from the International Registry of Acute Aortic Dissection

BACKGROUND

Acute aortic intramural hematoma (IMH) is an important subgroup of aortic dissection, and controversy surrounds appropriate management.

METHODS AND RESULTS

Patients with acute aortic syndromes in the International Registry of Acute Aortic Dissection (1996-2011) were evaluated to examine differences between patients (based on the initial imaging test) with IMH or classic dissection (AD). Of 2830 patients, 178 had IMH (64 type A [42%], 90 type B [58%], and 24 arch). Patients with IMH were older and presented with similar symptoms, such as severe pain. Patients with type A IMH were less likely to present with aortic regurgitation or pulse deficits and were more likely to have periaortic hematoma and pericardial effusion. Although type A IMH and AD were managed medically infrequently, type B IMH were more frequently treated medically. Overall in-hospital mortality was not statistically different for type A IMH compared to AD (26.6% versus 26.5%; P=0.998); type A IMH managed medically had significant mortality (40.0%), although less than classic AD (61.8%; P=0.195). Patients with type B IMH had a hospital mortality that was less but did not differ significantly (4.4% versus 11.1%; P=0.062) from classic AD. One-year mortality was not significantly different between AD and IMH.

CONCLUSIONS

Acute IMH has similar presentation to classic AD but is more frequently complicated with pericardial effusions and periaortic hematoma. Patients with IMH have a mortality that does not differ statistically from those with classic AD. A small subgroup of type A IMH patients are managed medically and have a significant in-hospital mortality.

[Intramural hematoma of the thoracic aorta: Medical treatment or surgery?]

Intramural hematoma (IMH) of the aorta is an uncommon entity. This disease shares many characteristics with acute aortic dissection. Treatment of IMH remains controversial. We report the case of a 58 years old man with hypertension disease who was admitted in emergency department with suspicion of acute aortic dissection. Transoesophageal echocardiography showed IMH involving the descending aorta which spread afterwards to the ascending aorta. Patient was treated medically and echocardiographic follow-up showed that aortic hematoma remains stable. Two years later, patient is alive and the last TEE reveals disappearance of hematoma in ascending aorta and decrease of it in descending aorta.

Clinical Outcomes of Medical Treatment of Acute Type A Intramural Hematoma

A retrospective study was performed in 30 patients who were treated for type A intramural hematoma from 1999 to 2008, of whom 24 were initially treated without surgical intervention. These 24 patients were followed up for 3.3 ± 3.5 years (range, 0 days to 10.0 years). Four hospital deaths occurred (hospital mortality, 16.7%), there were 2 late deaths, and 2 other patients needed an operation during the follow-up period. The event-free survival rate (freedom from death or surgery) at 5 years was significantly lower in patients with maximal aortic diameter ≤48 mm than in those with diameters <48 mm (28.6% ± 17.1% vs. 88.2% ± 7.8%). Maximal aortic diameter ≤48 mm and computed tomography findings of a small intimal defect were significant predictors of rupture or progression of ascending aortic dissection. The outcome of medical treatment for type A intramural hematoma was acceptable during both the early and late periods, but patients with a relatively large aortic diameter or an intimal defect in the ascending aorta have a high probability of adverse outcome, and must be considered for surgery.

Outcomes of patients with acute type a aortic intramural hematoma

BACKGROUND

The proper treatment option for patients with type A intramural hematoma (IMH), a variant form of classic aortic dissection (AD), remains controversial. We assessed the outcome of our institutional policy of urgent surgery for unstable patients and initial medical treatment for stable patients with surgery in cases with complications.

METHODS AND RESULTS

Among 357 consecutive patients with type A acute aortic syndrome, 101 (28.3%) had IMH and 256 had AD. Urgent operations were performed in 224 patients with AD (87.5%) and 16 with unstable IMH (15.8%; P<0.001). The remaining 85 stable IMH patients received initial medical treatment, and adverse clinical events developed in 31 patients (36.5%) within 6 months, which included development of AD (n=25), delayed surgery (n=25), or death (n=6). Initial aorta diameter and hematoma thickness were independent predictors for development of these events, and the best cutoff values were 55 and 16 mm, respectively. The overall hospital mortality was lower in IMH patients than in AD patients (7.9% [8/101] versus 17.2% [44/256]; P=0.0296) and was comparable to that of surgically treated AD patients (7.9% versus 10.7% [24/224]; P=0.56). The 1-, 2-, and 3-year survival rates of IMH patients were 87.6+/-3.6%, 84.9+/-3.7%, and 83.1+/-4.1%, respectively. There was no statistical difference of overall survival rates between patients with IMH and surgically treated AD patients (P=0.787).

CONCLUSIONS

The clinical outcome of IMH patients receiving treatment by our policy was comparable to that of surgically treated AD patients. However, adverse clinical events were not uncommon with medical treatment alone, and initial aorta diameter and hematoma thickness may identify patients who might benefit from urgent surgery.

Imaging features of intramural hematoma of the aorta

Intramural hematoma (IMH) is defined as localized hemorrhage within the aortic wall and is included in the acute aortic syndrome spectrum with aortic dissection and penetrating aortic ulcer. The mortality from IMH is similar to classic aortic dissection (21%). 16% of patients with IMH will evolve to classic aortic dissection over time. Despite this confusion exists regarding the precise definitions and radiologic features of IMH versus penetrating ulcers with mural thrombus and overt aortic dissection.

International Heterogeneity in Diagnostic Frequency and Clinical Outcomes of Ascending Aortic Intramural Hematoma

BACKGROUND

Differing diagnostic frequencies and management strategies for intramural hematoma (IMH) have been described in North American (NA)/European and Japanese/Korean studies.

METHODS

All publications including type-A aortic IMH were reviewed for details on patient demographics, treatment strategy, and clinical outcomes. Publications were stratified by the geographic region (NA/Europe or Japan/Korea).

RESULTS

IMH, as a percentage of aortic dissection, occurs more frequently in Japan/Korea versus NA/Europe (31.7% vs 10.9%, P < .0001). The proportion of patients treated with early medical therapy is greater in Japanese/Korean studies (77.9% vs 48.8% in NA/Europe, P < .0001). However, the overall mortality is significantly lower in Japan/Korea compared with NA/Europe (9.4% vs 20.6%, odds ratio = 2.80, P = .003) in part because of the lower mortality with early medical therapy (7.8% vs 33.3%, P < .0001).

CONCLUSION

There is significant international heterogeneity in the diagnosis and clinical outcomes of ascending IMH. IMH is diagnosed more frequently and has better overall outcomes in Japan/Korea.

Fluid-structure interaction within a layered aortic arch model

The response of wall stress to the elasticity of each layer in the aorta wall was investigated to understand the role of the different elastic properties of layers in the aortic dissection. The complex mechanical interaction between blood flow and wall dynamics in a three-dimensional arch model of an aorta was studied by means of computational coupled fluid-structure interaction analysis. The results show that stresses in the media layer are highest in three layers and that shear stress is concentrated in the media layer near to the adventitia layer. Hence, the difference in the elastic properties of the layers could be responsible for the pathological state in which a tear splits across the tunica media to near to the tunica adventitia and the dissection spreads along the laminar planes of the media layer where it is near the adventitia layer.