Immunoglobulin G4–positive ascending thoracic aortitis may be prone to dissection

IgG4 related disease and aortitis: an up-to-date review

Aortic involvement in immunoglobulin G4-related disease (IgG4-RD) is extremely rare and is often overlooked during the aortitis work-up. IgG4-related aortitis differs from non-IgG4-related aortitis in its histopathological features, site of involvement, laboratory markers, and treatment options. The histopathological examination of the vessel walls characteristically reveals adventitial thickening with intimal sparing, typically affecting the infrarenal abdominal aorta. In addition, inadequate knowledge about the disease often leads to delayed or missed diagnosis and undermanagement of a potentially treatable condition. Hence, in this paper, we review the unique clinical manifestations, laboratory markers, diagnostic features, current treatment strategies, and novel experimental therapeutic options in the management of IgG4-related aortitis.

Multidisciplinary diagnosis and management of inflammatory aortic aneurysms

BACKGROUND

Inflammatory abdominal aortic aneurysms (IAAAs) are a variant involving a distinct immunoinflammatory process, with nearly one half believed to be associated with IgG4-related disease (IgG4-RD).

METHODS

MEDLINE and Google Scholar searches were conducted for English-language publications relevant to inflammatory aortic aneurysms from January 1970 onward. The search terms included inflammatory aortic aneurysms, aortitis, periaortitis, IgG4-related disease, and retroperitoneal fibrosis. Relevant studies were selected for review based on their relevance.

RESULTS

Morphologically, IAAAs are characterized by a thickened aneurysm wall often displaying contrast enhancement and elevated metabolic activity on fluorine-18 fluorodeoxyglucose-positron emission tomography imaging. A strong association exists with perianeurysmal and retroperitoneal fibrosis. Although the rupture risk appears lower with IAAAs than with noninflammatory abdominal aortic aneurysms (AAAs), the currently recommended diameter threshold for operative management is the same. Open repair has been associated with increased morbidity compared with noninflammatory AAAs, and a retroperitoneal approach or minimal dissection transperitoneal approach has been recommended to avoid duodenal and retroperitoneal structural injuries. Endovascular aneurysm repair has been increasingly used, especially for patients unfit for open surgery. It is important to exclude an infectious etiology before the initiation of immunosuppressive therapy or operative repair. Multimodality imaging follow-up is critical to monitor disease activity and secondary involvement of retroperitoneal structures by the associated fibrotic process. Maintenance of immunosuppressive therapy will be needed postoperatively for most patients with active systemic disease, especially those with IgG4-RD and those with persistent symptoms. Additional interventions aimed at ureteral decompression could also be required, and lifelong follow-up is mandatory.

CONCLUSIONS

Preoperative multimodality imaging is a diagnostic cornerstone for assessment of the disease extent and activity. IgG4-RD is an increasingly recognized category of IAAAs, with implications for tailoring adjunctive medical therapy. Open surgical repair remains the procedure of choice, although endovascular aneurysm repair is increasingly being offered. Maintenance immunosuppressive therapy can be offered according to the disease activity as assessed by follow-up imaging studies.

IgG4 aortitis of the ascending thoracic aorta: A case report and literature review

IgG4 aortitis is a recently recognized entity that can have clinical and imaging features that mimic acute aortic syndrome. Therefore, it is imperative for radiologists to be aware of how to potentially differentiate the two. Although this entity has been previously described via case reports and meta-analysis in the context of inflammatory abdominal aortic aneurysm, very few cases of ascending aortic involvement have been reported. In this case report, we present a case of a 60-year-old female transferred from another facility for an initial diagnosis of intramural hematoma of the ascending aorta and later found to have IgG4 aortitis post aortic root repair. This is a histologically confirmed case of multi-segmented IgG4 aortitis with rare involvement of both ascending and infra-renal aorta. We will briefly discuss the pathophysiology of IgG4 aortitis, along with review of literature.

Overview of IgG4-related aortitis and periaortitis. A decade since their first description

Aortic involvement is relatively common in the context of IgG4-related disease (IgG4-RD). It includes IgG4-aortitis, and IgG4-(chronic) periaortitis (IgG4-CP). The latter overlaps with IgG4-retroperitoneal fibrosis (IgG4-RPF). Aortic wall thickening which characterizes these entities along with the presence of periaortic tissue in IgG4-CP, are often accompanied by aortic aneurysms, which belong to the group of the so-called inflammatory aneurysms. Both the thoracic and abdominal aorta can be affected. Aortitis appears to involve more often the former, while the opposite is the case for IgG4-CP. There is a lack of definitions and different classification criteria have been used to describe these entities. This report provides an overview on the current evidence of aortic involvement in IgG4-RD. It discusses the clinical, epidemiologic, serologic and histopathologic characteristics, as well as the imaging techniques used for their diagnosis and the therapeutic options and treatment outcomes. The differential diagnosis and underlying pathogenetic mechanisms are also discussed.

Immunoglobulin G4-related thoracic aortitis

Patients with immunoglobulin G4-related thoracic aortitis often have nonspecific symptoms, but pain in the chest or back is common. The rate of misdiagnosis of immunoglobulin G4-related thoracic aortitis is high, which may lead to mistreatment in extreme cases. A correct diagnosis should be based on comprehensive medical imaging, pathology, and laboratory and immunohistochemical results. Most patients' condition can be significantly improved using conservative or surgical treatment.

Acute type A aortic dissection - a review

Acute type A aortic dissection (ATAAD) is still one of the most challenging diseases that cardiac surgeons encounter. This review is based on the current literature and includes the results from the Nordic Consortium for Acute Type-A Aortic Dissection (NORCAAD) database. It covers different aspects of ATAAD and concentrates on the outcome of surgical repair. The diagnosis is occasionally delayed, and ATAAD is usually lethal if prompt repair is not performed. The dynamic nature of the disease, the variation in presentation and clinical course, and the urgency of treatment require significant attentiveness. Many surgical techniques and perfusion strategies of varying complexity have been described, ranging from simple interposition graft to total arch replacement with frozen elephant trunk and valve-sparing root reconstruction. Although more complex techniques may provide long-term benefit in selected patients, they require significant surgical expertise and experience. Short-term survival is first priority so an expedited operation that fits in with the surgeon's level of expertise is in most cases appropriate.

Never forget the aorta: a case report of IgG4-related disease causing aortitis

Background

Chest pain is a common reason for admission to the Emergency Department and aortic disease is a relatively frequent cause amongst the total number of admissions due to chest pain. IgG4-related disease (IgG4-RD) is a multi-organ immune-mediated condition that mimics several malignant, infectious, and inflammatory disorders.

Case summary

We report a rare case of IgG4-related aortitis complicated with severe aortic regurgitation and multivessel coronary artery disease in a 64-year-old man with a history of atypical chest pain. The diagnosis was made performing transthoracic echocardiography, transoesophageal echocardiography, and left heart catheterization; the aortitis was an incidental finding discovered by computed tomography angiography. Unusually, the positron emission tomography-computed tomography (PET-CT) scans did not reveal metabolic activity in the aortic wall. This last finding prompted us to exclude more aggressives arteritis (such as Horton's disease or Takayasu arteritis); syphilis infection and other infective or autoimmune diseases were excluded with laboratory tests. The patient underwent cardiac surgery with replacement of both the aortic valve and the ascending aorta, also performing a coronary aortic bypass graft (CABG). Despite the PET-CT scans were negative in the aortic wall, the histological specimens showed diffuse lymphoid infiltration, fibro-atheromatosis lesions, and medium-interstitial hyperplasia compatible with aortic atherosclerosis and IgG4-RD. The post-surgery course was free of complications and the patient was discharged in good clinical condition. He was referred to the Rheumatologic Department and a corticosteroid therapy has been started.

Discussion

The growing recognition of IgG4-related systemic disease as a clinical entity underscores the importance of considering this diagnosis in patients with any type of idiopathic aortitis and aortic valve disease. Noteworthy, the PET-CT scans could be negative in this disease, so histological exams are mandatory to make the diagnosis; in our case an unusual post-surgery histopathological finding prompted us to diagnose a rare, unrecognized disease and allowed us to treat the patient properly.

Modulation of Immune-Inflammatory Responses in Abdominal Aortic Aneurysm: Emerging Molecular Targets

Abdominal aortic aneurysm (AAA), a deadly vascular disease in human, is a chronic degenerative process of the abdominal aorta. In this process, inflammatory responses and immune system work efficiently by inflammatory cell attraction, proinflammatory factor secretion and subsequently MMP upregulation. Previous studies have demonstrated various inflammatory cell types in AAA of human and animals. The majority of cells, such as macrophages, CD4+ T cells, and B cells, play an important role in the diseased aortic wall through phenotypic modulation. Furthermore, immunoglobulins also greatly affect the functions and differentiation of immune cells in AAA. Recent evidence suggests that innate immune system, especially Toll-like receptors, chemokine receptors, and complements are involved in the progression of AAAs. We discussed the innate immune system, inflammatory cells, immunoglobulins, immune-mediated mechanisms, and key cytokines in the pathogenesis of AAA and particularly emphasis on a further trend and application of these interventions. This current understanding may offer new insights into the role of inflammation and immune response in AAA.

IgG4-Aortopathy: An Underappreciated Cause of Non-Infectious Thoracic Aortitis

IgG4 related thoracic aortitis is a recent addition to the differential diagnosis for inflammatory aortic disease - a condition which is often underappreciated until complications arise such as aneurysmal formation or aortic dissection. Currently, IgG4 aortitis remains a post-surgical diagnosis reliant on positive immunohistochemistry findings. Management is guided by the extent of disease involvement, which can be gauged by serum IgG4 levels and radiological findings. Options include surgical resection, corticosteroid therapy and steroid-sparing agents to prevent relapses.

Immunology of IgG4-related disease

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition that derives its name from the characteristic finding of abundant IgG4(+) plasma cells in affected tissues, as well as the presence of elevated serum IgG4 concentrations in many patients. In contrast to fibrotic disorders, such as systemic sclerosis or idiopathic pulmonary fibrosis in which the tissues fibrosis has remained largely intractable to treatment, many IgG4-RD patients appear to have a condition in which the collagen deposition is reversible. The mechanisms underlying this peculiar feature remain unknown, but the remarkable efficacy of B cell depletion in these patients supports an important pathogenic role of B cell/T cell collaboration. In particular, aberrant T helper type 2 (Th2)/regulatory T cells sustained by putative autoreactive B cells have been proposed to drive collagen deposition through the production of profibrotic cytokines, but definitive demonstrations of this hypothesis are lacking. Indeed, a number of unsolved questions need to be addressed in order to fully understand the pathogenesis of IgG4-RD. These include the identification of an antigenic trigger(s), the implications (if any) of IgG4 antibodies for pathophysiology and the precise immunological mechanisms leading to fibrosis. Recent investigations have also raised the possibility that innate immunity might precede adaptive immunity, thus further complicating the pathological scenario. Here, we aim to review the most recent insights on the immunology of IgG4-RD, focusing on the relative contribution of innate and adaptive immune responses to the full pathological phenotype of this fibrotic condition. Clinical, histological and therapeutic features are also addressed.

Accentuating and Opposing Factors Leading to Development of Thoracic Aortic Aneurysms Not Due to Genetic or Inherited Conditions

Understanding and unraveling the pathophysiology of thoracic aortic aneurysm (TAA), a vascular disease with a potentially high-mortality rate, is one of the next frontiers in vascular biology. The processes leading to the formation of TAA, of unknown cause, so-called degenerative TAA, are complex. This review advances the concept of promoters and inhibitors of the development of degenerative TAA. Promoters of TAA development include age, blood pressure elevation, increased pulse pressure, neurohumeral factors increasing blood pressure, inflammation specifically IFN-γ, IL-1 β, IL-6, TNF-α, and S100 A12; the coagulation system specifically plasmin, platelets, and thrombin as well as matrix metalloproteinases (MMPs). SMAD-2 signaling and specific microRNAs modulate TAA development. The major inhibitors or factors opposing TAA development are the constituents of the aortic wall (elastic lamellae, collagen, fibulins, fibronectin, proteoglycans, and vascular smooth muscle cells), which maintain normal aortic dimensions in the face of aortic wall stress, specific tissue MMP inhibitors, plasminogen activator inhibitor-1, protease nexin-1, and Syndecans. Increases in promoters and reductions in inhibitors expand the thoracic aorta leading to TAA formation.

[IgG4-related disease treatment in 2014: Update and literature review]

IgG4-related disease is an inflammatory disorder characterized by a polyclonal lymphoplasmacytic tissue infiltrate, with numerous IgG4+ plasmocytes, evolving toward fibrosis. The disease is heterogeneous and affects several tissues and organs synchroneously or metachroneously. Both the fibrosis and the tumor forming characteristics of the disease can be responsible of irreversible tissue damage. For these reasons treatment is usually necessary. A dramatic response is usually observed with steroid treatment but relapses are frequent. Immunosuppressive agents and rituximab are used as second line treatments. We review here previous studies on treatment and suggest general recommendations for the treatment and follow up of patients with IgG4-related disease.

Ascending aortitis: a clinicopathological study of 21 cases in a series of 300 aortic repairs

There are few single-institution clinicopathological series of aortitis. In this study, all ascending aneurysms were prospectively evaluated pathologically with ≥6 aortic sections over a 6-year period.Of 300 ascending aortic resections, there were 21 cases of aortitis (7%), in 11 women and 10 men (mean 67, range 41-88 years). There were 19 patients with aneurysms, and two patients with sclerosing periaortitis, clinically suspected to have intramural haematoma. Of the 19 patients with aneurysms (11 women), two had prior temporal arteritis, one ankylosing spondylitis, one IgA nephropathy, one undifferentiated autoimmune disease, one Lyme disease, and one fibromyalgia. In only two patients was aortitis suspected before surgery as the cause of aneurysm. Four patients developed distal aortic aneurysm requiring repeat surgery. Valve replacement or repair was necessary in nine patients, and two patients died after surgery. There were no significant differences between patients with and without autoimmune disease. The histological features were necrotising aortitis in 18 of 19 patients with aneurysmal aortitis, and there was one case of non-necrotising aortitis. One valve showed autoimmune valvulitis, congenitally bicuspid associated with ankylosing spondylitis. Necrotising aortitis was classified as acute (n = 5), healing (n = 9), and healed (n = 4). Acute necrotising aortitis was associated with need for valve replacement (p = 0.01) and younger age (p = 0.01). The healed phase had subtle histological features, sparse medial inflammation, marked medial attenuation, and chronic adventitial inflammation. Two patients with periaortitis demonstrated marked fibroinflammatory thickening of the adventitia with histological features typical of IgG4-related disease; neither had systemic symptoms. Ascending aortitis is histologically diverse, most frequently of the medial necrotising type, and is usually not suspected pre-operatively. Awareness of the histological spectrum is necessary for pathological diagnosis.

Immunoglobulin G4-related aortitis mimicking an intramural hematoma

Immunoglobulin G4-related systemic disease is a rare entity with various presenting symptoms. We report the case of a 34-year-old Chinese male who presented with immunoglobulin G4-related aortitis and the unusual symptom of hoarseness of voice. He underwent distal ascending aorta and total aortic arch replacement.