Aortic intramural hematoma: aspects of pathogenesis 2011

Outcome Comparison Between Open and Endovascular Aortic Repair for Retrograde Type A Intramural Hematoma With Intimal Tear in the Descending Thoracic Aorta: A Retrospective Observational Study

Objective: The optimal treatment modality for retrograde type A intramural hematoma (IMH) remains debatable. This study evaluated and compared surgical outcomes and aortic remodeling after open aortic repair and thoracic endovascular aortic repair (TEVAR) in patients with retrograde type A IMH with a primary intimal tear or ulcer like projection in the descending aorta.

Methods: A single center, retrospective observational study was performed on patients with retrograde type A IMH undergoing either open aortic repair and TEVAR. From June 2009 and November 2019, 46 patients with retrograde type A IMH who received either open aortic repair or TEVAR at our institution were reviewed for clinical outcomes, including post-operative mortality/morbidity, re-intervention rate and aortic remodeling.

Results: 33 patients underwent open aortic repair and 13 underwent TEVAR. Median age was 68 years (interquartile range [IQR] 15.2 years) and 63 years (IQR 22.5 years) for the open repair group and TEVAR group, respectively. The median duration of follow-up for TEVAR patients was 37.6 months and 40.3 months for open aortic repair. No difference in the 5-year estimated freedom from all-cause mortality (82.1 vs. 87.8%, p = 0.34), re-intervention (82.5 vs. 93.8%, p = 0.08), and aortic-related mortality (88.9 vs. 90.9%, p = 0.88) were observed between the TEVAR and open repair group, respectively; however, the open repair group had a significantly higher 30-day composite morbidity (39.4 vs. 7.7%, p = 0.037). All patients from both treatment groups had complete resolution of the IMH in the ascending aorta. With regard to the descending thoracic aorta, TEVAR group had a significantly greater regression in the diameter of the false lumen or IMH thickness when compared to the open repair group [median 14mm (IQR 10.1) vs. 5mm (IQR 9.5), p < 0.001].

Conclusion: TEVAR and open aortic repair were both effective treatments for retrograde type A IMH, in which no residual ascending aortic IMH was observed during follow-up. TEVAR was also associated with lower post-operative composite morbidities and better descending aortic remodeling. In selected patients with retrograde type A IMH, TEVAR might be a safe, effective alternative treatment modality.

Outcomes of intramural hematoma involving the ascending aorta and extending into the descending thoracic aorta

OBJECTIVE

The optimal treatment of intramural hematoma (IMH) involving the ascending aorta remains controversial. This study aimed to analyze the results of the management of patients with acute IMH involving the ascending aorta and extending into the descending thoracic aorta, to compare outcomes of descending thoracic endovascular aortic repair (TEVAR) with that of medical therapy (MT), and to assess the risk factors associated with adverse aortic events.

METHODS

We retrospectively analyzed all patients diagnosed with acute IMH involving the ascending aorta and extending into the descending thoracic aorta from January 2012 to December 2019. The primary end points during follow-up were aortic disease-related death and adverse aorta-related events that required surgical or endovascular treatment, such as aortic rupture, the progression of aortic disease, or endoleak.

RESULTS

We identified a total of 135 patients with acute IMH involving the ascending aorta and extending into the descending thoracic aorta, of whom 104 underwent descending TEVAR (group 1) and 31 were managed with MT (group 2). Freedom from adverse aorta-related events at 1, 3, and 5 years was significantly higher for patients who underwent descending TEVAR compared with those managed with MT (89.2%, 88.2%, and 84.0% vs 74.2%, 74.2%, and 74.2%, respectively; P = .026). The 1-, 3-, and 5-year survival rates for patients in the descending TEVAR group was 100%, 100%, and 100%, respectively, which was significantly higher than the survival of the MT group: 93.5%, 93.5%, and 81.9%, respectively (P = .002). On a univariate analysis among patients receiving MT, those who suffered adverse aorta-related events showed a higher prevalence of renal insufficiency (55.6% vs 9.1%; P = .003). In MT patients, multivariate analysis showed that renal insufficiency was the only independent risk factor associated with adverse aorta-related events (hazard ratio, 8.691; 95% confidence interval, 2.056-36.737; P = .003).

CONCLUSIONS

Based on our study, compared with MT, descending TEVAR might be the more favorable treatment for patients with IMH involving the ascending aorta and extending into the descending thoracic aorta. Patients with renal insufficiency are more likely to experience adverse aorta-related events, which implies the need for subsequent intervention or an increased risk of mortality. The risk factor would be helpful for clinical decision-making.

Aortic Delamination-A Possible Precursor of Impending Catastrophe

Aortic diameter is a powerful predictor of adverse aortic events, such as aortic rupture or dissection, forming the basis of prophylactic surgical repair criteria. Limited evidence is available regarding the association of aortic wall thickness (AWT) with these adverse aortic events. We present the case and surgical video of a 73-year-old man with chest pain and an increased AWT, who underwent ascending aortic repair and deep hemiarch placement under deep hypothermic circulatory arrest. Surgical pathology demonstrated evidence of aortic delamination and medial separation, indicative of an impending dissection. The patient recovered uneventfully, and his chest pain ultimately resolved after open repair. In this patient, increased AWT was felt to be the precursor to a potential aortic catastrophe.

Virtual versus true non-contrast dual-energy CT imaging for the diagnosis of aortic intramural hematoma

PURPOSE

To assess whether virtual non-contrast (VNC) images derived from contrast dual-layer dual-energy computed tomography (DL-DECT) images could replace true non-contrast (TNC) images for aortic intramural hematoma (IMH) diagnosis in acute aortic syndrome (AAS) imaging protocols by performing quantitative as well as qualitative phantom and clinical studies.

MATERIALS AND METHODS

Patients with confirmed IMH were included retrospectively in two centers. For in vitro imaging, a custom-made phantom of IMH was placed in a semi-anthropomorphic thorax phantom (QRM GmbH) and imaged on a DL-DECT at 120 kVp under various conditions of patient size, radiation exposure, and reconstruction modes. For in vivo imaging, 21 patients (70 ± 13 years) who underwent AAS imaging protocols at 120 kVp were included. In both studies, contrast-to-noise ratio (CNR) between hematoma and lumen was compared using a paired t test. Diagnostic confidence (1 = non-diagnostic, 4 = exemplary) for VNC and TNC images was rated by two radiologists and compared. Effective radiation doses for each acquisition were calculated.

RESULTS

In both the phantom and clinical studies, we observed that the CNRs were similar between the VNC and TNC images. Moreover, both methods allowed differentiating the hyper-attenuation within the hematoma from the blood. Finally, we obtained equivalent high diagnostic confidence with both VNC and TNC images (VNC = 3.2 ± 0.7, TNC = 3.1 ± 0.7; p = 0.3). Finally, by suppressing TNC acquisition and using VNC, the mean effective dose reduction would be 40%.

CONCLUSION

DL-DECT offers similar performances with VNC and TNC images for IMH diagnosis without compromise in diagnostic image quality.

KEY POINTS

• Dual-layer dual-energy CT enables virtual non-contrast imaging from a contrast-enhanced acquisition. • Virtual non-contrast imaging with dual-layer dual-energy CT reduces the number of acquisitions and radiation exposure in acute aortic syndrome imaging protocol. • Dual-layer dual-energy CT has the potential to become a suitable imaging tool for acute aortic syndrome.

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.

Outcomes and management of type A intramural hematoma

BACKGROUND

Initial optimal management of acute type A aortic dissection (ATAAD) with intramural hematoma (ATAIMH) remains controversial, especially between centers in the Eastern vs. Western worlds. We examined the literature and our experience to report outcomes after repair of ATAIMH.

METHODS

We reviewed the hospital, follow-up clinic records and online mortality databases for all patients who presented to our center for open repair of ATAAD between 1999 and 2014. Preoperative characteristics, early and long-term outcomes were compared between classic ATAAD vs. ATAIMH. Survival was analyzed using Kaplan-Meier and log-rank statistics.

RESULTS

Of the 523 repaired ATAAD, 101 patients (19%) presented with IMH and 422 (81%) had classic dissection. ATAIMH were significantly older (64.8±12.9 vs. 56.8±14.6 years; P<0.001), more commonly females (39% vs. 26%; P=0.010), had poor baseline renal function (i.e., glomerular filtration rate) (P<0.017), more retrograde dissections (27% vs. 8.3%; P<0.001), and less distal malperfusion (5% vs. 15%; P<0.001). Age greater than 60 years, female sex, retrograde dissection, and Marfan syndrome were strongly correlated with ATAIMH. Time to repair for ATAIMH was longer (median, 55.3 vs. 9.8 hours; P<0.001) with one death in ATAIMH within three days of presentation (0.9% vs. 6%; P=0.040). In all, 30-day mortality in ATAIMH was not different from classic ATAAD (12% vs.16%; P=0.289). A significantly lower incidence of postoperative dialysis in ATAIMH was noted (10% vs. 19%; P=0.034). When adjusted for age and renal function, late survival was improved with IMH (P<0.039).

CONCLUSIONS

ATAIMH continues to be associated with significant morbidity and mortality, comparable to classic aortic dissection. A multidisciplinary management approach involving aggressive medical management and risk stratification for timely surgical intervention, along with genetic profiling, is recommended for optimal care. Long-term monitoring is mandatory to assess compliance to medical therapy and recognition of evolving complications.

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.

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.

Eleven years of experience with the neurologic complications in Korean patients with acute aortic dissection: a retrospective study

Background

This study attempts to explore the clinical features, possible mechanisms and prognosis of the neurologic complications in patients with acute aortic dissection (AD).

Methods

Medical records of 278 consecutive patients with AD (165 with type A and 113 with type B dissection) over 11.5 years were retrospectively analyzed for clinical history, CT findings, neurologic complications and outcome. Neurologic complications were classified into early-onset or delayed-onset complications. Independent t-test or Chi-square test (or Fisher exact test) was used for comparing the different groups. Multivariable logistic regression analysis was performed to determine the independent association between variables.

Results

The mean age of the included patients (145 male and 133 female) was 59.4 years (range 19–91 years). 41 patients (14.7%) had a neurologic complication, which included 21 with early-onset complication and 23 with delayed-onset complication, including 3 with both. Advanced age and classic type of dissection were independently associated with the neurologic complication in patients with type A dissection. The most frequent manifestation was ischemic stroke (26 patients, 9.4%), followed by hypoxic encephalopathy (9, 3.2%), ischemic neuropathy (5, 1.8%), spinal cord ischemia (5, 1.8%), seizure (2, 0.7%), hoarseness (1, 0.4%) and septic encephalopathy (1, 0.4%). Overall in-hospital mortality was 10.1%, whereas the complicated group had a mortality rate of 43.9%. Renal impairment, pulse deficit, neurologic complication and nonsurgical treatment were independent variables for determining in-hospital mortality in patients with type A dissection.

Conclusions

The dominance of neurologic symptom in the early stage of AD may make its early diagnosis difficult. Besides chest pain and widened mediastinum in chest x-ray, variable neurologic symptoms including left hemiparesis with asymmetric pulse and hypotension may suggest underlying AD.

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.

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 presenting with painless recurrent syncope

A patient presented with recurrent syncope due to transient severe hypotension. The patient's history, physical examination, and initial baseline investigation did not suggest a cardiovascular cause. After fluid resuscitation, a raised jugular venous pulse was noted. Bedside transthoracic echocardiogram showed a pericardial effusion and a proximally dilated aorta. Computed tomography of the thorax confirmed these findings and also demonstrated an intramural hematoma of the proximal aortic wall.The patient was transferred to a cardiothoracic center, where he was at first treated medically. He then developed sudden cardiogenic shock due to pericardial tamponade and was successfully operated on.It is important to recognize an acute intramural hematoma of the proximal aortic wall as a cardiothoracic emergency. This condition can present atypically, but nevertheless warrants urgent surgical intervention, equal to type A aortic dissection. Echocardiography can help in making the diagnosis.

Intramural collection caused by contrast extravasation into the ascending aortic wall

Cardiac catheterization is a procedure routinely performed worldwide, with an estimated amount of 61,000 coronary angioplasties performed in the UK annually. Associated mortality--in the region of 0.1-0.2%--is minimal and complication rate approximately 1.5%. The most serious complications described are embolic stroke, cardiac chamber perforation, aortic dissection, coronary occlusions or dissection, and major peripheral vascular complications, including retroperitoneal haematoma and life-threatening haemorrhage. We report the case of a 75-year old patient who had inadvertent contrast agent injection into the aortic wall, leading to a localized contrast collection within the tunica media. This complication has been described before but only in association with coronary artery dissection. It is important to diagnose and manage such a situation, as most iodinated intravascular contrast agents exert a high osmotic load and thereby lead to tissue oedema and necrosis on extravasation. We describe the management of the case and discuss relevant therapeutic strategies.

Recent advances in the diagnosis of acute aortic syndromes

INTRODUCTION

Acute aortic syndrome (AAS) is an acute lesion of the aortic wall involving the aortic media. In patients presenting with AAS, establishing a timely diagnosis is of paramount importance as mortality from AAS increases by 1 - 2% per hour. Acute aortic syndrome comprises a variety of pathologically distinct life-threatening conditions such as aortic dissection, intramural hematoma (IMH) of the aorta, penetrating aortic ulcer (PAU), traumatic transection and symptomatic aortic aneurysm.

AREAS COVERED

The aim of this article was to review recent progress in the diagnosis and therapeutic management of these syndromes. In the past few years, imaging techniques have increased our understanding of the natural history of these disease entities. Patients presenting with AAS require immediate diagnosis in order to rapidly initiate adequate therapeutic measures. Diagnostic imaging modalities that can be used for diagnosing this condition are transthoracic and transesophageal echocardiography (TTE and TEE, respectively), computed tomography angiography (CTA), magnetic resonance imaging and angiography in combination with intravascular ultrasound (IVUS).

EXPERT OPINION

Patients presenting with AAS require immediate diagnosis for rapid initiation of adequate therapeutic measures. The best method to correctly diagnose acute aortic dissection and its complications is complementary use of CTA, TEE and angiography in combination with IVUS to improve visualization of aortic syndromes and to guide aortic stent graft implantation.