IgG4 assozierte Arteriitis der Koronararterien

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IgG4-related coronary disease is a form of inflammatory arteritis and/or periarteritis of the coronary arteries and a form of IgG4-related disease.

Epidemiology

Similar to atherosclerotic coronary artery disease IgG4-related coronary disease affects older people above 60 years of age. There is a clear male predominance .

Associations

Clinical conditions associated with IgG4-related coronary disease include :

  • aortitis and periaortitis
  • arteritis and periarteritis of non-coronary arteries
  • inflammatory aneurysm
  • pericarditis
  • other forms of cardiac involvement: myocardium, cardiac valves
  • other organ involvement: pancreas, salivary glands, lymph nodes, etc.

Clinical presentation

Patient complaints and clinical presentation are nonspecific and can vary and in the case of coronary stenosis can mimic those of coronary artery disease .

Biochemically IgG4-related cardiovascular disease is characterized by an elevated serum IgG4 concentration ≥ 1.35 mg/L .

Complications

IgG4-related coronary disease can lead to the following conditions :

Pathology

IgG4-related cardiovascular disease is characterized by a lymphoblastic infiltration and fibrosclerotic inflammation of the adventitia whereas the media is less affected .

Macroscopic appearance

Macroscopically IgG4-related coronary disease is characterized by an irregular inflammatory adventitial thickening of reddish to brown color .

Microscopic appearance

The histological appearance of coronary involvement of IgG4-related disease includes the following :

  • lymphoplasmacytic infiltration 
  • storiform fibrosis - radially arranged collagen fibers weaving through tissue
  • infiltration of IgG4-positive plasma cells
  • obliterative phlebitis

Radiographic features

General radiographic features of IgG4-related disease includes the following :

  • inflammatory vasculitis
  • aneurysmal change
  • pseudotumor formation
Coronary angiography

Invasive coronary angiography (ICA) is the modality of choice in the setting of an acute coronary syndrome and the evaluation of coronary stenosis. It can also detect luminal coronary aneurysms. Its role in the detection of the typical IgG4-related adventitial changes is however limited and might require intravascular ultrasound (IVUS), which might show a thickened hypoechoic circumferential lesion .

CT

Cardiac CTA with multiplanar and curved reformations (including vessel short-axis) have been recommended for the evaluation of IgG4-related coronary disease .

Differentiation of fibrosclerotic inflammatory wall-thickening from coronary thrombus formation might benefit from a delayed contrast enhancement .

CT imaging features include :

  • diffuse or partial arterial mural thickening (> 2 mm)
  • homogenous wall enhancement especially in a late phase
  • coronary pseudotumor formation and encasement - “pigs-in-a-blanket sign”
  • absence of calcifications
  • associated luminal stenosis
  • partial aneurysmal dilatation
MRI

Cardiac MRI can depict pseudotumor formation and encasement of the coronary arteries even though the detection of significant stenosis is less good compared to cardiac CTA due to lesser spatial resolution. On the other hand, it can offer a comprehensive evaluation with respect to disease-related complications and valuable information regarding the differentiation versus other cardiac masses .

Signal characteristics
  • cine SSFP: hypointense
  • T2FS/STIR: hyperintense
  • IRGRE/PSIR (Gd): focal perivascular late enhancement 
Nuclear medicine
PET-CT

PET-CT shows abnormally increased FDG uptake in the vessel wall compared to vessel lumen and can provide important information in respect to disease activity .

Radiology report

The radiological report should include a description of the following features:

location and extent of the affected vessels

  • aneurysmal dilatations
  • thrombus formation
  • coronary stenosis
  • pseudotumor formation
  • pericardial disease (thickened pericardium, pericardial effusions)
  • aortic involvement

Treatment and prognosis

IgG4-related disease is known to respond to corticosteroid therapy. Rituximab is another agent which has been used in the treatment .

Complications

Corticosteroid therapy is thought to carry a risk of increased thrombogenicity or aneurysm rupture .

History and etymology

A general concept of IgG4-related autoimmune disease was first described in 2003 by Terumi Kamisawa and colleagues .

Differential diagnosis

The differential diagnosis of IgG4-related coronary disease include the following :

Practical points

  • strongly consider an additional delayed phase on coronary CTA
  • on cardiac MRI consider the following
    • coronary MR angiography with respiratory-gated 3D-imaging (e.g. native 3D-SSFP wholeheart and/or 3D-mDixon after gadolinium contrast)
    • include transaxial T2FS/STIR-black-blood of the whole thoracic aorta

See also

Siehe auch:
Assoziationen und Differentialdiagnosen zu IgG4 assozierte Arteriitis der Koronararterien:
Arteriitis
der Koronararterien
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