Endomyocardial biopsies in the diagnosis of myocardial involvement in systemic lupus erythematosus.

BACKGROUND: Endomyocardial biopsy (EMB) is considered the gold standard for diagnosing myocardial involvement in most inflammatory conditions, including systemic lupus erythematosus (SLE). However, EMBs are rarely performed, and most of the myocardial histopathology reports in SLE consist of postmortem data. We therefore sought to describe the histopathologic findings of contemporary EMBs in SLE performed in clinical practice.

METHODS: A retrospective review of histopathology reports from SLE patients who underwent EMB from 1994 to 2017 was performed. A total of 41 SLE patients had cardiac pathology reports. Of these, 11 histopathology reports were EMBs, and the remaining were valvular specimens.

RESULTS: A total of 11 SLE EMBs were reviewed. It was found that 45% of the patients had hypertension, 27% had coronary artery disease, 9% had hyperlipidemia, and 36% had end-stage renal disease. None had diabetes or smoked. The mean left ventricular ejection fraction was 37%. On histopathology, 10 had mild interstitial fibrosis, 9 had myocyte hypertrophy, 3 had organized blood clots, and 3 had a mild infiltration of lymphocytes and macrophages without clear evidence of myocarditis. None had vasculitis, endocarditis, ischemia, amyloid deposition, or lamellar or curvilinear inclusions.

CONCLUSION: EMBs are rarely performed in SLE. In this case series, nonspecific interstitial fibrosis and myocyte hypertrophy were the most common findings, suggesting EMBs have limited value in the diagnosis of cardiac involvement in SLE and rather rule out competing conditions. These data support the need for diagnostic methods with high sensitivity and specificity for SLE heart disease.