The Heart in Inflammatory Myopathies

Howard Van Gelder, MDa and Christina Charles-Schoeman, MD, MSb∗CCharles@mednet.ucla.edu,     aDivision of Rheumatology, Department of Internal Medicine, Olive View-UCLA Medical Center, Los Angeles, CA, USA; bDivision of Rheumatology, Department of Medicine, University of California Los Angeles, 1000 Veteran Avenue, Room 32-59, Los Angeles, CA 90095, USA

∗Corresponding author.

Cardiac involvement in the idiopathic inflammatory myopathies (IIM) has been reported in 5% to 70% of cases. It is estimated that between 15% and 55% of deaths are related to heart disease in patients with dermatomyositis (DM) and polymyositis (PM). Increased atherosclerotic disease in IIM patients has also been reported and is associated with traditional risk factors such as hypertension and dyslipidemia. In the current article we review some of the more recent literature on clinical manifestations and outcomes of cardiovascular disease in IIM patients.

Keywords

Idiopathic inflammatory myopathies

Cardiovascular disease

Dermatomyositis

Polymyositis

Inclusion body myositis

Key points

• Systemic autoimmune diseases are becoming increasingly linked to accelerated risks of cardiovascular disease and events, and the idiopathic inflammatory myopathies (IIM) are not an exception to this growing pattern.

• Traditional risk factors for coronary artery disease, such as hypertension and hyperlipidemia, are associated with cardiovascular disease and events in patients with IIM.

• IIM patients with cardiac involvement are at increased risk for overall mortality when compared with IIM patients without cardiac involvement.

• The effects of immunosuppression on cardiac disease and cardiovascular events in IIM patients requires further investigation in carefully controlled studies.

• It is imperative that physicians treating IIM patients perform a routine cardiovascular risk assessment at the onset of diagnosis.

Introduction

Inflammatory muscle diseases are a diverse set of systemic autoimmune rheumatic disorders that are defined by chronic muscle weakness, muscle fatigue, and mononuclear cell infiltration into skeletal muscle. Idiopathic inflammatory myopathies (IIMs) primarily affect the trunk and proximal limb muscles with or without skin involvement.1 There are various subtypes, including polymyositis (PM), dermatomyositis (DM), juvenile myositis, amyopathic myositis, and inclusion body myositis (IBM). The Bohan and Peter criteria have been widely used in diagnosing PM/DM (Box 1), however updated classification criteria for these disorders which include IBM are currently in development.2 The reported overall incidence of IIMs is approximately 10 cases per million the United States. Diagnosis of IIMs is usually based on a combination of clinical signs and symptoms along with key laboratory and diagnostic testing. Among the important blood tests include measurements of enzyme levels expressed from damaged muscle and autoantibodies, including myositis-specific antibodies such as anti-synthetase antibodies (anti-Jo1 and others), anti-SRP, Anti-Mi2, anti-MDA5, anti-MJ, and anti-TIF1-gamma.3 Diagnostic studies include abnormal electromyographic measurements of affected muscle, magnetic resonance imaging suggesting muscle edema, and muscle biopsy showing the characteristic abnormalities. Medical treatments generally (excluding IBM) consist of immune suppression in the form of corticosteroids followed by a variety of disease-modifying antirheumatic drugs depending on the organ systems involved.4

Box 1   Modified Bohan and Peter criteria for the diagnosis of PM and DM

Individual criteria

1. Symmetric proximal muscle weakness

2. Muscle biopsy evidence of myositis

3. Increase in serum skeletal muscle enzymes

4. Characteristic electromyographic pattern

5. Typical rash of dermatomyositis

Diagnostic criteria

Polymyositis

Definite: all of 1–4, Probable: any 3 of 1–4, Possible: any 2 of 1–4

Dermatomyositis

Definite: 5 plus any 3 of 1–4, Probable: 5 plus any 2 of 1–4, Possible: 5 plus any of 1–4

Data from Oddis CV, Ascherman DP. Clinical features, classification, and epidemiology of inflammatory muscle disease. In: Hochberg M, Silman A, Smolen J, et al, editors. Rheumatology. 5th edition. New York: Elsevier; 2011.

The IIMs can be complicated by many disorders of the internal organs (Box 2). Arthritis, gastrointestinal tract (dysphagia), skin (primarily in DM), and lung (interstitial lung disease) are among the many well-known organ systems involved with IIM. Cardiovascular disease is a risk factor for death among patients with PM and DM even though clinically evident heart involvement is rarely reported. However, many subclinical manifestations of heart disease have been reported, suggesting that clinical disease may in fact be underreported.5 The literature evaluating the subject of cardiac involvement in IIM has not been extensive, although interest has recently increased in this area as better diagnostic tools become available and a focus on improving treatment outcomes continues. Herein, we present a brief review focused on the most recent developments in cardiovascular disease and IIM.

Box 2   Organ Involvement in IIM

Muscle

• Atrophy, weakness, dysfunction

Skeletal

• Joint contracture, osteoporosis with fracture, avascular necrosis, arthropathy

Cutaneous

• Calcinosis, alopecia, scarring, pokiloderma, lipodystrophy

Gastrointestinal

• Dysphagia, dysmotility, infarction

Pulmonary

• Dysphonia, impaired lung function, pulmonary fibrosis, hypertension

Cardiovascular

• Hypertension, ventricular dysfunction, angina, myocardial infarction

Peripheral vascular disease

• Tissue pulp loss, digit loss, thrombosis, claudication

Endocrine

• Growth failure, delay in secondary sexual characteristics, hirsutism, irregular menses, amenorrhea, diabetes, infertility, sexual dysfunction

Ocular severity

• Cataract, vision loss

Infection

• Chronic infection, multiple infections

Data from National Institute of Environmental Health Sciences. IMACS Myositis Damage Index 2001. Available at: http://www.niehs.nih.gov/research/resources/assets/docs/myositis_damage_index_pdf_format.pdf. Accessed September 30, 2013.

Methods

Articles were searched on pubmed.gov for the keywords of “Myositis” or “IIM” or “Myopathy” with the boolean operator AND followed by “Cardiovascular Disease” or “Cardiac” or “Cardiomyopathy” and appropriate articles were chosen. Only articles in English published after 2005 were chosen for inclusion if they were deemed to be appropriate for the current review as determined by the authors. In addition, Web searches for online textbooks in rheumatology and IIM were included besides the initial PubMed search and the same inclusion criterion was applied. Further articles were then located based on references found in the initial article or text review.

Results

Cardiomyopathies: Myocarditis

Cardiomyopathies can be defined as myocardial disorders in which the heart muscle is structurally and functionally abnormal in the absence of coronary artery disease (CAD), hypertension, valvular heart disease, and congenital heart disease.6 Cardiac magnetic resonance imaging (CMR) provides 3-dimensional data on cardiac anatomy, function, tissue characterization, coronary and microvascular perfusion, and valvular disease without ionizing radiation. Several case reports and case series have demonstrated a link between myocarditis identified by MRI and inflammatory...